JPH11311937A - Device and method for recording/reproducing optical information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an optical system for multiple recording or reproducing of information using holography. SOLUTION: The pickup 11 of an optical information recording/reproducing device spatially modulates a laser beam emitted from a light source 25 according to recorded information by a space light modulator 18 to generate an information beam, and further, spatially modulates the phase of the laser beam from the light source 25 by a phase space light modulator 17 to generate a recording reference beam whose phase is spatially modulated. An optical information recording medium 1 is irradiated by the information beam and the recording reference beam so as to be converged on positions different from each other, and the information is recorded on a hologram layer 3 in an interference pattern due to interference between the information beam and the recording reference beam reflected by a reflection film 5. The information beam and the recording reference beam are positioned based on the information recorded in an address servo area 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording apparatus and method for recording information on an optical information recording medium using holography, and an optical information reproducing apparatus for reproducing information from an optical information recording medium using holography. Apparatus and method.

[0002]

2. Description of the Related Art In general, holographic recording in which information is recorded on a recording medium using holography is performed by superimposing light having image information and reference light inside a recording medium, and generating interference at that time. This is performed by writing stripes on a recording medium. When reproducing the recorded information, the recording medium is irradiated with reference light, whereby the image information is reproduced by diffraction due to interference fringes.

In recent years, volume holography, especially digital volume holography, has been developed in the practical range for ultra-high-density optical recording, and has attracted attention. Volume holography is a method in which interference fringes are written three-dimensionally by actively utilizing the thickness direction of the recording medium. There is a feature that can be achieved. And
Digital volume holography is a computer-oriented holographic recording method that uses the same recording medium and recording method as volume holography, but limits image information to be recorded to binary digital patterns. In this digital volume holography, for example, image information such as an analog picture is once digitized, developed into two-dimensional digital pattern information, and recorded as image information. At the time of reproduction, this digital pattern information is read out and decoded to return to the original image information for display. Thereby, even if the SN ratio (signal-to-noise ratio) is somewhat poor at the time of reproduction, the original information can be reproduced very faithfully by performing differential detection or encoding the binary data to correct errors. It becomes possible.

FIG. 75 is a perspective view showing a schematic configuration of a recording / reproducing system in conventional digital volume holography. This recording / reproducing system includes a spatial light modulator 10 for generating an information light 102 based on two-dimensional digital pattern information.
1, a lens 103 for condensing the information light 102 from the spatial light modulator 101 and irradiating the hologram recording medium 100 with the information light 102. Reference light irradiating means (not shown) for irradiating light 104, CCD (charge coupled device) array 107 for detecting reproduced two-dimensional digital pattern information, and reproduction light 105 emitted from hologram recording medium 100 And a lens 106 for condensing the light and irradiating the light onto the CCD array 107. For the hologram recording medium 100, a crystal such as LiNbO ₃ is used.

In the recording / reproducing system shown in FIG. 75, at the time of recording, information such as an original image to be recorded is digitized, and signals of 0 or 1 are further arranged two-dimensionally to generate two-dimensional digital pattern information. . One piece of two-dimensional digital pattern information is called page data. Here, it is assumed that page data # 1 to #n are multiplex-recorded on the same hologram recording medium 100. In this case, first, the spatial light modulator 101 selects transmission or light blocking for each pixel based on the page data # 1, whereby the spatially modulated information light 1 is selected.
02 is generated and irradiated on the hologram recording medium 100 via the lens 103. At the same time, the hologram recording medium 10
0, the reference light 1 from a direction θ1 substantially orthogonal to the information light 102.
04, and inside the hologram recording medium 100,
The interference fringes formed by the superposition of the information beam 102 and the reference beam 104 are recorded. In order to increase the diffraction efficiency, the reference light 104 is transformed into a flat beam by a cylindrical lens or the like, and the interference fringes are changed to the hologram recording medium 100.
To be recorded in the thickness direction. At the time of recording the next page data # 2, the reference light 104 is irradiated from the angle θ2 different from θ1, and the reference light 104 and the information light 1 are irradiated.
02 can be multiplex-recorded on the same hologram recording medium 100. Similarly, at the time of recording other page data # 3 to #n, information is multiplex-recorded by irradiating the reference beam 104 from different angles θ3 to θn. A hologram in which information is multiplex-recorded is called a stack. In the example shown in FIG. 75, the hologram recording medium 100 has a plurality of stacks (stack 1, stack 2,..., Stack m,...).

In order to reproduce any page data from the stack, the stack may be irradiated with the reference beam 104 having the same incident angle as when the page data was recorded. Then, the reference light 104 is selectively diffracted by an interference fringe corresponding to the page data, and a reproduction light 105 is generated. This reproduction light 105 is transmitted through a lens 106
, And the two-dimensional pattern of the reproduction light is detected by the CCD array 107. Then, the information such as the original image is reproduced by decoding the detected two-dimensional pattern of the reproduction light in a manner reverse to that at the time of recording.

[0007]

In the configuration shown in FIG. 75, information can be multiplex-recorded on the same hologram recording medium 100. However, in order to record information at an extremely high density, the hologram recording medium 100 must be The positioning of the information light 102 and the reference light 104 becomes important. However, in the configuration shown in FIG. 75, the hologram recording medium 10
Since there is no information for positioning in the hologram recording medium 100, the information beam 102 and the reference beam 10
The positioning of 4 can only be performed mechanically, and high-precision positioning is difficult. Therefore, the removability (easiness of transferring the hologram recording medium from one recording / reproducing apparatus to another recording / reproducing apparatus and performing the same recording / reproducing) is poor, and random access is difficult and high-density recording is difficult. There is a problem that is. Further, in the configuration shown in FIG. 75, the optical axes of the information light 102, the reference light 104, and the reproduction light 105 are spatially arranged at mutually different positions, so that the optical system for recording or reproduction becomes large. There is a problem that.

Meanwhile, in holographic recording, various multiplex recording methods have been conventionally proposed in order to increase the recording capacity by improving the recording density. One of them is angle multiplexing as shown in FIG. However, in this angle multiplexing, since it is necessary to change the angle of the reference light, there is a problem that an optical system for recording or reproduction becomes particularly large and complicated.

Conventionally, as a method of multiplex recording in holographic recording, besides the angle multiplexing described above, for example, a document "JF Heanue et al.," Recall of linear combinati "
onsof stored data pages based on phase-code multip
lexing in volume holography ”Optics Letters, Vol.1
9, No. 14, pages 1079 to 1081, 1994) and JF Heanue et al. “Encrypted holographic data storage based on orth.
ogonal-phase-code multiplexing "Applied Optics, Vo
l.34, No. 26, pp. 6012-6015, 1995 ”, for example, the phase encoding multiplexing (phase encoding) multiplexing described in the literature“ Eiji Yagyu et al., “Wavelength multiplexed hologram using PHB” Research on new real-time recording and reproduction "IEICE Technical Report, EDI93-87, HC93-54, 1-5 pages, 1993
And the like, hole-burning type wavelength division multiplexing and the like described in "Year".

However, in any of the multiplex recording methods, in the conventionally proposed optical system for recording or reproduction, the optical axes of the information light, the reference light and the reproduction light are spatially different from each other. The hologram recording medium has a problem that the optical system for recording or reproduction becomes large, and the hologram recording medium itself has no information for positioning. However, there is a problem in that it is difficult to accurately perform the positioning, and it is not possible to achieve a dramatic improvement in recording density.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide an optical information recording medium capable of multiplex-recording information on an optical information recording medium on which information is recorded using holography. Apparatus and method, and optical information reproducing apparatus and method for reproducing information from an optical information recording medium on which information is recorded in such a manner that an optical system for recording or reproducing can be configured to be small. An object of the present invention is to provide an optical information recording device and method and an optical information reproducing device and method.

A second object of the present invention is, in addition to the first object, an optical information recording apparatus and method capable of accurately positioning light for recording or reproduction on an optical information recording medium. And an optical information reproducing apparatus and method.

[0013]

According to a first aspect of the present invention, there is provided an optical information recording apparatus for recording information on an optical information recording medium having an information recording layer on which information is recorded using holography. An information recording apparatus, comprising: an information light generating means for generating information light carrying information; and a phase modulation means for spatially modulating the phase of light, wherein the phase is spatially modulated by the phase modulation means. Recording reference light generating means for generating a recording reference light; and information generated by the information light generating means such that information is recorded on the information recording layer by an interference pattern due to interference between the information light and the recording reference light. A recording optical system for irradiating the information recording layer with the light and the recording reference light generated by the recording reference light generating means from the same surface side.

According to a sixth aspect of the present invention, there is provided an optical information recording method for recording information on an optical information recording medium having an information recording layer on which information is recorded using holography. Generating an information beam carrying information, spatially modulating the phase of the light, generating a spatially modulated recording reference beam, and combining the information beam and the recording reference beam for information recording. The layer is irradiated from the same side, and information is recorded on the information recording layer by an interference pattern due to interference between the information light and the recording reference light.

In the optical information recording apparatus according to the first aspect or the optical information recording method according to the sixth aspect, the information light carrying information and the recording reference light whose phase is spatially modulated are formed on the information recording layer. Is irradiated from the same side, and information is recorded on the information recording layer by an interference pattern caused by interference between the information light and the recording reference light.

According to a seventh aspect of the present invention, in the optical information reproducing apparatus, information is recorded by using an interference pattern caused by interference between an information light carrying information and a recording reference light whose phase is spatially modulated by using holography. An optical information reproducing apparatus for reproducing information from an optical information recording medium provided with an information recording layer, comprising: a phase modulation means for spatially modulating the phase of light, wherein the phase is spatially modulated by the phase modulation means. A reproduction reference light generating means for generating a reproduction reference light modulated on the information recording layer, and irradiating the information recording layer with the reproduction reference light generated by the reproduction reference light generation means; A reproduction optical system that collects reproduction light generated from the information recording layer by irradiation from the same side as the side on which the information recording layer is irradiated with the reproduction reference light, and a reproduction optical system that collects the reproduction light from the information recording layer. It is obtained by a detecting means for detecting the raw light.

In the optical information reproducing method according to the eleventh aspect, information is recorded by an interference pattern due to interference between an information light carrying information and a recording reference light whose phase is spatially modulated by using holography. An optical information reproducing method for reproducing information from an optical information recording medium having an information recording layer, comprising: spatially modulating a phase of light to generate a reproduction reference light having a spatially modulated phase. Generate and irradiate the information recording layer with the reproduction reference light, the reproduction light generated from the information recording layer by irradiating the reproduction reference light,
The information recording layer is collected from the same side as the side on which the reproduction reference light is irradiated, and the collected reproduction light is detected.

According to the optical information reproducing apparatus of the present invention, the information recording layer is irradiated with a reproducing reference light whose phase is spatially modulated. Reproduction light generated from the information recording layer by irradiation with light is collected from the same surface side as the side on which the information recording layer is irradiated with the reproduction reference light, and the collected reproduction light is detected.

According to a twelfth aspect of the present invention, there is provided an optical information recording apparatus having an information recording layer on which information is recorded by utilizing holography while causing a change in light absorption at a wavelength position of incident light in a light absorption spectrum. An optical information recording apparatus for recording information on an information recording medium, comprising: a wavelength selecting means for selecting a wavelength of light applied to an information recording layer from a plurality of wavelengths; Information light generating means for generating an information light carrying information having a predetermined wavelength, a recording reference light generating means for generating a recording reference light having a wavelength selected by the wavelength selecting means, and an information recording layer The information light generated by the information light generating means and the recording light generated by the recording reference light generating means so that the information is recorded by an interference pattern due to the interference between the information light and the recording reference light. And use the reference beam, in which a recording optical system for irradiating from the same side with respect to the information recording layer.

According to a fifteenth aspect of the present invention, there is provided an optical information recording method in which a light absorption ratio is changed at a wavelength position of incident light in a light absorption spectrum, and an information recording layer on which information is recorded using holography is provided. An optical information recording method for recording information on an information recording medium, wherein a wavelength of light applied to the information recording layer is selected from a plurality of wavelengths, and the selected wavelength has the selected wavelength. Generates the carried information light,
Generating a recording reference light having a selected wavelength, irradiating the information light and the recording reference light with the information recording layer from the same surface side, and irradiating the information recording layer with the information light and the recording reference light. The information is recorded according to an interference pattern caused by the interference.

In the optical information recording apparatus according to the twelfth aspect or the optical information recording method according to the fifteenth aspect, an information light having a selected wavelength and carrying information, a recording reference light having a selected wavelength and Is irradiated onto the information recording layer from the same side, and information is recorded on the information recording layer by an interference pattern due to interference between the information light and the recording reference light.

According to a sixteenth aspect of the present invention, there is provided an optical information reproducing apparatus utilizing holography, having an information light having a wavelength selected from a plurality of wavelengths and carrying information, and a wavelength selected from a plurality of wavelengths. An optical information reproducing apparatus for reproducing information from an optical information recording medium having an information recording layer in which information is recorded by an interference pattern due to interference with a recording reference light, the light irradiating the information recording layer Wavelength selecting means for selecting a wavelength from among a plurality of wavelengths, a reproducing reference light generating means for generating a reproducing reference light having a wavelength selected by the wavelength selecting means, and a reproducing reference light generating means The information recording layer is irradiated with the reproduction reference light generated by the reproduction reference light, and the reproduction light generated from the information recording layer by irradiation with the reproduction reference light is referred to the information recording layer for reproduction. A reproducing optical system for collecting from the same side as the side to be irradiated with, in which a detecting means for detecting the reproduction light collected by the reproducing optical system.

According to a nineteenth aspect of the present invention, there is provided an optical information reproducing method using holography, an information beam having a wavelength selected from a plurality of wavelengths and carrying information, and a wavelength selected from a plurality of wavelengths. An optical information reproducing method for reproducing information from an optical information recording medium having an information recording layer in which information is recorded by an interference pattern due to interference with a recording reference light, comprising: Is selected from among a plurality of wavelengths, a reproducing reference light having the selected wavelength is generated, and the information recording layer is irradiated with the reproducing reference light, and the reproducing reference light is irradiated. Thus, the reproduction light generated from the information recording layer is collected from the same side as the side on which the information recording layer is irradiated with the reproduction reference light, and the collected reproduction light is detected.

According to the optical information reproducing apparatus of the present invention or the optical information reproducing method of the present invention, a reproducing reference light having a selected wavelength is applied to the information recording layer. Reproduction light generated from the information recording layer by the irradiation is collected from the same side as the side on which the information recording layer is irradiated with the reproduction reference light, and the collected reproduction light is detected.

According to a twentieth aspect of the present invention, there is provided an optical information recording apparatus having an information recording layer on which information is recorded by utilizing holography while causing a change in light absorption at a wavelength position of incident light in a light absorption spectrum. An optical information recording apparatus for recording information on an information recording medium, comprising: a wavelength selecting means for selecting a wavelength of light applied to an information recording layer from a plurality of wavelengths; Having a wavelength, information light generating means for generating information light carrying information, including a phase modulation means for spatially modulating the phase of the light, having a wavelength selected by the wavelength selection means, and Information is recorded on the information recording layer by an interference pattern due to interference between the information light and the recording reference light on the information recording layer, and a recording reference light generating means for generating a recording reference light whose phase is spatially modulated by the phase modulation means. A recording optical system for irradiating the information recording layer with the information light generated by the information light generating means and the recording reference light generated by the recording reference light generating means from the same surface side. It is something.

According to a twenty-third aspect of the present invention, there is provided an optical information recording method comprising the steps of causing a change in an optical absorptance at a wavelength position of incident light in an optical absorption spectrum and providing an information recording layer on which information is recorded by utilizing holography. An optical information recording method for recording information on an information recording medium, wherein a wavelength of light applied to the information recording layer is selected from a plurality of wavelengths, and the selected wavelength has the selected wavelength. Generates the carried information light,
Spatially modulating the phase of the light, having a selected wavelength,
And generating a recording reference beam whose phase is spatially modulated,
The information light and the recording reference light are irradiated to the information recording layer from the same side, and information is recorded on the information recording layer by an interference pattern caused by interference between the information light and the recording reference light.

[0027] In the optical information recording apparatus according to the twentieth aspect or the optical information recording method according to the twenty-third aspect, an information light having a selected wavelength and carrying information;
A recording reference light whose phase is spatially modulated is applied to the information recording layer from the same side, and information is recorded on the information recording layer by an interference pattern caused by interference between the information light and the recording reference light. Is done.

According to a twenty-fourth aspect of the present invention, there is provided an optical information reproducing apparatus which utilizes holography to select an information light having information having a wavelength selected from a plurality of wavelengths and an information light selected from a plurality of wavelengths. An optical information reproducing apparatus for reproducing information from an optical information recording medium having an information recording layer in which information is recorded by an interference pattern due to interference with a recording reference light having a wavelength and a phase spatially modulated. There is a wavelength selecting means for selecting a wavelength of light to be applied to the information recording layer from a plurality of wavelengths, and a phase modulating means for spatially modulating the phase of the light, the wavelength selected by the wavelength selecting means. And a reproducing reference light generating means for generating a reproducing reference light whose phase is spatially modulated by the phase modulating means, and information recording of the reproducing reference light generated by the reproducing reference light generating means. For layers And a reproducing optical system that collects reproducing light generated from the information recording layer by being irradiated with the reproducing reference light from the same surface side as the side on which the information recording layer is irradiated with the reproducing reference light. And detection means for detecting the reproduction light collected by the reproduction optical system.

An optical information reproducing method according to a twenty-seventh aspect uses holography to select information light having a wavelength selected from a plurality of wavelengths and carrying information, and a wavelength selected from a plurality of wavelengths. An optical information reproducing method for reproducing information from an optical information recording medium having an information recording layer in which information is recorded by an interference pattern due to interference with a recording reference light whose phase is spatially modulated. The wavelength of the light to be applied to the information recording layer is selected from a plurality of wavelengths, the phase of the light is spatially modulated, the light has the selected wavelength, and the phase is spatially modulated. A reproduction reference light is generated, and the information recording layer is irradiated with the reproduction reference light, and the reproduction light generated from the information recording layer by being irradiated with the reproduction reference light is emitted to the information recording layer. From the same side as the side that irradiates the reproduction reference beam Condensed, it is used to detect the collected reproduction light.

[0030] In the optical information reproducing apparatus described in claim 24 or the optical information reproducing method described in claim 27, the reproduction reference light having the selected wavelength and the phase is spatially modulated is recorded on the information recording layer. The reproduction light generated from the information recording layer by being irradiated with the reproduction reference light,
The information recording layer is collected from the same side as the side on which the reproduction reference light is irradiated, and the collected reproduction light is detected.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings. The first embodiment of the present invention is an example in which multiplex recording by phase encoding (phase encoding) multiplexing is enabled. FIG. 1 is an explanatory diagram showing a configuration of an optical information recording apparatus according to the present embodiment and a pickup in an optical information recording / reproducing apparatus as an optical information reproducing apparatus and an optical information recording medium according to the present embodiment. FIG. 1 is a block diagram illustrating an overall configuration of an optical information recording / reproducing device according to an embodiment.

First, the configuration of the optical information recording medium according to the present embodiment will be described with reference to FIG. The optical information recording medium 1 includes a hologram layer 3 as an information recording layer on which information is recorded using volume holography, a reflective film 5 and a disc-shaped transparent substrate 2 formed of polycarbonate or the like. , And the protective layer 4 are laminated in this order. On the boundary surface between the hologram layer 3 and the protective layer 4, a plurality of address servo areas 6 as linear positioning areas extending linearly in the radial direction are provided at predetermined angular intervals. The fan-shaped section is the data area 7. address·
In the servo area 6, information for performing focus servo and tracking servo by a sampled servo method and address information are recorded in advance by emboss pits or the like. Note that focus servo can be performed using the reflection surface of the reflection film 5. For example, wobble pits can be used as information for performing the tracking servo. The transparent substrate 2 is, for example, 0.6 mm
The following appropriate thickness and the hologram layer 3 have an appropriate thickness of 10 μm or more, for example. The hologram layer 3 is formed of a hologram material whose optical characteristics such as a refractive index, a dielectric constant, and a reflectance change when irradiated with light. Examples of the hologram material include a photopolymer (photopol) manufactured by Dupont.
ymers) HRF-600 (product name) or the like is used. The reflection film 5 is formed of, for example, aluminum.

Next, the configuration of the optical information recording / reproducing apparatus according to the present embodiment will be described with reference to FIG. The optical information recording / reproducing apparatus 10 includes a spindle 81 on which the optical information recording medium 1 is mounted, a spindle motor 82 for rotating the spindle 81, and a spindle motor 82 for maintaining the rotation speed of the optical information recording medium 1 at a predetermined value. And a spindle servo circuit 83 for controlling the motor 82. The optical information recording / reproducing apparatus 10 further irradiates the optical information recording medium 1 with information light and recording reference light to record information, and irradiates the optical information recording medium 1 with reproduction reference light. And
A pickup 11 for detecting reproduction light and reproducing information recorded on the optical information recording medium 1, and a driving device 84 for moving the pickup 11 in a radial direction of the optical information recording medium 1 are provided. ing.

The optical information recording / reproducing device 10 further outputs a focus error signal FE,
A detection circuit 85 for detecting the tracking error signal TE and the reproduction signal RF, and an actuator in the pickup 11 is driven based on the focus error signal FE detected by the detection circuit 85 to move the objective lens to the optical information recording medium. A focus servo circuit 86 for performing focus servo by moving the focus servo circuit in the thickness direction 1;
A tracking servo circuit 87 that drives an actuator in the pickup 11 based on the tracking error signal TE detected by the step 5 to move the objective lens in the radial direction of the optical information recording medium 1 to perform tracking servo.
And a slide servo circuit 88 that controls the drive device 84 based on the tracking error signal TE and a command from a controller to be described later to perform a slide servo for moving the pickup 11 in the radial direction of the optical information recording medium 1. .

The optical information recording / reproducing apparatus 10 further decodes output data of a later-described CCD array in the pickup 11 to reproduce data recorded in the data area 7 of the optical information recording medium 1 or to detect the data in the detection circuit. A signal processing circuit 89 for reproducing a basic clock or determining an address from a reproduction signal RF from the optical disc 85;
A controller 90 for controlling the whole of the controller 90, and an operation unit 91 for giving various instructions to the controller 90. The controller 90 receives the basic clock and address information output from the signal processing circuit 89 and controls the pickup 11, the spindle servo circuit 83, the slide servo circuit 88, and the like. The spindle servo circuit 83 receives the basic clock output from the signal processing circuit 89. The controller 90 includes a CPU (Central Processing Unit), R
It has an OM (read only memory) and a RAM (random access memory), and the CPU implements the function of the controller 90 by executing a program stored in the ROM using the RAM as a work area. It has become.

Detection circuit 85, focus servo circuit 8
6. The tracking servo circuit 87 and the slide servo circuit 88 correspond to the position control means in the present invention.

Next, the configuration of the pickup 11 according to the present embodiment will be described with reference to FIG. When the optical information recording medium 1 is fixed to the spindle 81, the pickup 11 includes an objective lens 12 facing the transparent substrate 2 side of the optical information recording medium 1, and the objective lens 12 is attached to the optical information recording medium 1 in the thickness direction. In addition, an actuator 13 movable in the radial direction, and a two-divided optical rotation plate 14 and a prism block 15 arranged in order from the objective lens 12 side are provided on the opposite side of the optical information recording medium 1 in the objective lens 12. The two-part optical rotation plate 14 includes an optical rotation plate 14L disposed on the left side of the optical axis in FIG. 1 and a light rotation plate 14R disposed on the right side of the optical axis in FIG. The optical rotation plate 14L rotates the polarization direction by + 45 °, and
R rotates the polarization direction by -45 degrees.
The prism block 15 has a semi-reflective surface 15a and a reflective surface 15b arranged in this order from the two-part optical rotation plate 14 side. Both the semi-reflective surface 15a and the reflective surface 15b are inclined at an angle of 45 ° with respect to the optical axis direction of the objective lens 12 and arranged in parallel with each other.

The pickup 11 further includes a prism block 19 disposed on the side of the prism block 15. The prism block 19 is disposed at a position corresponding to the semi-reflective surface 15a of the prism block 15, and has a reflective surface 19a parallel to the semi-reflective surface 15a and a reflective surface 15b.
And a semi-reflective surface 19b parallel to the reflective surface 15b.

The pickup 11 further includes, between the prism block 15 and the prism block 19, a convex lens 16 and a phase spatial light which are sequentially arranged from the prism block 15 at positions corresponding to the semi-reflective surface 15 a and the reflective surface 19 a. A modulator 17 and a spatial light modulator 18 disposed between the prism blocks 15 and 19 at positions corresponding to the reflection surface 15b and the semi-reflection surface 19b are provided.

The phase spatial light modulator 17 has a large number of pixels arranged in a lattice pattern, and can spatially modulate the phase of light by selecting the phase of emitted light for each pixel. It has become. As the phase spatial light modulator 17, a liquid crystal element can be used. The phase spatial light modulator 17 corresponds to the phase modulation means in the present invention.

The spatial light modulator 18 has a large number of pixels arranged in a lattice, and modulates light spatially according to light intensity by selecting a light transmitting state or a light blocking state for each pixel. Thus, an information light carrying information can be generated. As the spatial light modulator 18, a liquid crystal element can be used. Spatial light modulator 18
Constitutes the information light generating means in the present invention.

After the return light from the optical information recording medium 1 passes through the spatial light modulator 18, the pickup 11
A prism array 19 is provided with a CCD array 20 as a detection means arranged in a direction reflected by the semi-reflection surface 19 b of the prism block 19.

The pickup 11 further includes a beam splitter 23, a collimator lens 24, and a light source device 25 arranged in this order on the side of the prism block 19 opposite to the spatial light modulator 18 from the prism block 19 side. I have. The beam splitter 23 has a normal direction of 45 ° with respect to the optical axis direction of the collimator lens 24.
It has an inclined semi-reflective surface 23a. Light source device 25
Emits coherent linearly polarized light. For example, a semiconductor laser can be used.

The pickup 11 further includes a light source device 25
A photodetector 26 arranged in a direction in which light from the side is reflected by the semi-reflective surface 23a of the beam splitter 23,
On the opposite side of the beam splitter 23 from the photodetector 26, a convex lens 27, a cylindrical lens 28, and a four-segment photodetector 29 arranged in this order from the beam splitter 23 side are provided. The photodetector 26 receives light from the light source device 25, and its output is used to automatically adjust the output of the light source device 25. The quadrant photodetector 29 is shown in FIG.
As shown in the figure, the optical information recording medium 1 has four light receiving portions 29a to 29d divided by a dividing line 30a parallel to a direction corresponding to a track direction and a dividing line 30b in a direction orthogonal to the dividing line 30a. I have. The cylindrical lens 28 is arranged such that the central axis of the cylindrical surface makes an angle of 45 ° with the dividing lines 30a and 30b of the four-divided photodetector 29.

The phase spatial light modulator 17, the spatial light modulator 18, and the light source device 25 in the pickup 11 are controlled by the controller 90 in FIG. The controller 90 controls the phase spatial light modulator 1
7 holds information of a plurality of modulation patterns for spatially modulating the phase of light. The operation unit 91
Can select an arbitrary modulation pattern from a plurality of modulation patterns. Then, the controller 90 provides the phase spatial light modulator 17 with information on the modulation pattern selected by itself or the modulation pattern selected by the operation unit 91 in accordance with a predetermined condition. According to the information of the modulation pattern to be obtained, the phase of the light is spatially modulated by the corresponding modulation pattern.

Each semi-reflective surface 1 in the pickup 11
The reflectivities of 5a and 19b are appropriately set, for example, so that the intensity of the information light incident on the optical information recording medium 1 and the intensity of the recording reference light are equal.

FIG. 3 is a block diagram showing a configuration of a detection circuit 85 for detecting the focus error signal FE, the tracking error signal TE and the reproduction signal RF based on the output of the four-split photodetector 29. The detection circuit 85 includes an adder 31 that adds the outputs of the diagonal light receiving units 29a and 29d of the four-division photodetector 29,
Diagonal photodetectors 29b, 29 of split photodetector 29
an adder 32 that adds each output of c, a subtractor 33 that calculates a difference between an output of the adder 31 and an output of the adder 32, and generates a focus error signal FE by an astigmatism method,
The adder 34 adds the outputs of the light receiving units 29a and 29b adjacent to each other along the track direction of the four-segment photodetector 29, and adds the outputs of the light receiving units 29c and 29d adjacent to the four-segment photodetector 29 along the track direction. Adder 35, a subtractor 36 that calculates a difference between an output of the adder 34 and an output of the adder 35, and generates a tracking error signal TE by a push-pull method, and an output of the adder 34 and the adder 35. And an adder 37 for adding the output of the adder to generate a reproduction signal RF. In the present embodiment, the reproduction signal RF is a signal obtained by reproducing information recorded in the address servo area 6 on the optical information recording medium 1.

Next, the operation of the optical information recording / reproducing apparatus according to the present embodiment will be described in the order of servo, recording and reproduction. Note that the optical information recording medium 1 is controlled by the spindle motor 82 to be controlled so as to maintain a specified number of rotations in any of servo, recording, and reproduction.

First, the operation during servo will be described with reference to FIG. At the time of servo, all the pixels of the spatial light modulator 18 are set in a transmission state. The output of the light emitted from the light source device 25 is set to a low output for reproduction. The controller 90 predicts the timing at which the light emitted from the objective lens 12 passes through the address servo area 6 based on the basic clock reproduced from the reproduction signal RF.
The above setting is made while the outgoing light passes through the address servo area 6.

The light emitted from the light source device 25 is converted into a parallel light beam by the collimator lens 24, enters the beam splitter 23, and a part of the light amount is transmitted and partially reflected by the semi-reflective surface 23a. The light reflected by the semi-reflective surface 23a is received by the photo detector 26. The light transmitted through the semi-reflective surface 23a enters the prism block 19, and a part of the light amount passes through the semi-reflective surface 19b. The light transmitted through the semi-reflective surface 19b passes through the spatial light modulator 18, is reflected by the reflective surface 15b of the prism block 15, a part of the light amount is transmitted through the semi-reflective surface 15a, and
Passes through the objective lens 12 and is converged on the information recording medium 1 so as to converge on the boundary surface between the hologram layer 3 and the protective layer 4 in the optical information recording medium 1.
This light is reflected by the reflection film 5 of the optical information recording medium 1, and is modulated by emboss pits in the address servo area 6 and returns to the objective lens 12 side.

The return light from the optical information recording medium 1 is converted into a parallel light flux by the objective lens 12, passes through the split optical rotation plate 14 again, enters the prism block 15, and a part of the light quantity is partially reflected by the semi-reflective surface 15a. Through. The return light transmitted through the semi-reflective surface 15a is reflected by the reflective surface 15a, and
And a part of the light amount passes through the semi-reflective surface 19 b of the prism block 19. The return light transmitted through the semi-reflective surface 19b enters the beam splitter 23, a part of the light amount is reflected by the semi-reflective surface 23a, passes through the convex lens 27 and the cylindrical lens 28 in order, and is detected by the quadrant photodetector 29. You. Then, based on the output of the quadrant photodetector 29, the focus error signal FE, the tracking error signal TE, and the reproduction signal RF are generated by the detection circuit 85 shown in FIG.
Based on these signals, focus servo and tracking servo are performed, and the reproduction of the basic clock and the determination of the address are performed.

In the above setting at the time of servo,
The pickup 11 has a configuration of a pickup for recording and reproducing data on and from a normal optical disk such as a CD (compact disk), a DVD (digital video disk or digital versatile disk), and an HS (hyper storage disk). Is the same as Therefore, the optical information recording / reproducing device 10 according to the present embodiment can be configured to have compatibility with a normal optical disk device.

Here, A-polarized light and B-polarized light used in the following description are defined as follows. That is, as shown in FIG. 10, the A polarized light is a linear polarized light obtained by rotating the S polarized light at −45 ° or the P polarized light by + 45 °, and the B polarized light is the S polarized light at + 45 ° or the P polarized light at −45 °. It is assumed that the direction of polarization is linearly polarized light. The polarization directions of the A polarized light and the B polarized light are orthogonal to each other. Note that S-polarized light is linearly polarized light whose polarization direction is perpendicular to the incident surface (the paper surface in FIG. 1), and P-polarized light is linearly polarized light whose polarization direction is parallel to the incident surface.

Next, the operation at the time of recording will be described. FIG. 6 is an explanatory diagram showing the state of the pickup 11 during recording. At the time of recording, the spatial light modulator 18 selects a transmissive state (hereinafter, also referred to as ON) and a blocked state (hereinafter, also referred to as OFF) for each pixel according to information to be recorded, and transmits light passing therethrough. The information light is generated by spatial modulation. In the present embodiment, one pixel of information is represented by two pixels, and one of two pixels corresponding to one bit of information is always turned on and the other is turned off.

Further, the phase spatial light modulator 17 modulates the passing light for each pixel according to a predetermined modulation pattern.
A phase difference of 0 (rad) or π (ra
By selectively applying d), the phase of the light is spatially modulated to generate the recording reference light in which the phase of the light is spatially modulated. The controller 90 provides the phase spatial light modulator 17 with information on the modulation pattern selected by itself or the modulation pattern selected by the operation unit 91 in accordance with predetermined conditions, and the phase spatial light modulator 17
According to the information of the modulation pattern given from 0, the phase of the passing light is spatially modulated.

The output of the light emitted from the light source device 25 is pulsed to a high output for recording. The controller 90
Predicts the timing at which the output light of the objective lens 12 passes through the data area 7 based on the basic clock reproduced from the reproduction signal RF. Set. While the light emitted from the objective lens 12 passes through the data area 7, focus servo and tracking servo are not performed, and the objective lens 12 is fixed. In the following description, it is assumed that the light source device 25 emits P-polarized light.

As shown in FIG. 6, the P-polarized light emitted from the light source device 25 is converted into a parallel light beam by the collimator lens 24, enters the beam splitter 23, and a part of the light amount passes through the semi-reflective surface 23a. Transmit, prism block 1
9 is incident. The light incident on the prism block 19 is
Part of the light amount is transmitted through the semi-reflective surface 19b, and part of the light amount is reflected by the semi-reflective surface 19b. The light transmitted through the semi-reflective surface 19b passes through the spatial light modulator 18 and, at that time, is spatially modulated according to information to be recorded, and becomes information light. This information light is reflected by the reflection surface 15 b of the prism block 15, and a part of the light amount passes through the semi-reflection surface 15 a and passes through the two-rotation optical rotation plate 14. Here, the light that has passed through the optical rotation plate 14L of the two-part optical rotation plate 14 has its polarization direction rotated by + 45 ° to become A-polarized light, and the light that has passed through the optical rotation plate 14R has its polarization direction rotated by −45 °, It becomes B-polarized light. The information light that has passed through the two-part optical rotation plate 14 is condensed by the objective lens 12 and converges on the boundary surface between the hologram layer 3 and the protective layer 4 in the optical information recording medium 1, that is, on the reflective film 5. The optical information recording medium 1 is irradiated.

On the other hand, the semi-reflective surface 1 of the prism block 19
The light reflected by 9b is reflected by the reflection surface 19a, passes through the phase spatial light modulator 17, and at this time, the phase of the light is spatially modulated according to a predetermined modulation pattern, and the reference light for recording is used. Becomes This recording reference light is light that passes through the convex lens 16 and converges. A part of the recording reference light is reflected by the semi-reflection surface 15 a of the prism block 15 and passes through the two-rotation optical rotation plate 14. Where, here, 2
The light that has passed through the optical rotation plate 14L of the split optical rotation plate 14 has its polarization direction rotated by + 45 °, becomes A-polarized light, and
The light that has passed through R is rotated by -45 ° in the polarization direction and becomes B-polarized light. The reference light for recording that has passed through the two-segment optical rotation plate 14 is condensed by the objective lens 12 and irradiates the optical information recording medium 1, and once has the smallest diameter before the boundary surface between the hologram layer 3 and the protective layer 4. After convergence so that
The light passes through the hologram layer 3 while diverging.

FIGS. 7 and 8 are explanatory views showing the state of light during recording. In these figures, the symbol denoted by reference numeral 61 indicates P-polarized light, the symbol denoted by reference numeral 63 indicates A-polarized light, and the symbol denoted by reference numeral 64 indicates B-polarized light.

As shown in FIG. 7, the information light 51L passing through the optical rotation plate 14L of the two-part optical rotation plate 14 becomes A-polarized light, and is radiated to the optical information recording medium 1 via the objective lens 12, and The light passes through the layer 3, converges to have the smallest diameter on the reflection film 5, is reflected by the reflection film 5, and passes through the hologram 3 again. The recording reference light 52L that has passed through the optical rotation plate 14L of the two-segment optical rotation plate 14 becomes A-polarized light, is radiated to the information recording medium 1 via the objective lens 12, and forms a light beam between the hologram layer 3 and the protective layer 4. After converging so as to have the smallest diameter once before the boundary surface, the light passes through the hologram layer 3 while diverging. Then, in the hologram layer 3, the A-polarized information light 51L reflected by the reflection film 5 and the A-polarized recording reference light 52L traveling to the reflection film 5 side.
Interfere with each other to form an interference pattern, and when the output of the light emitted from the light source device 20 becomes high, the interference pattern is volumetrically recorded in the hologram layer 3.

As shown in FIG. 8, the information light 51R that has passed through the optical rotation plate 14R of the two-part optical rotation plate 14 becomes B-polarized light, and is applied to the information recording medium 1 via the objective lens 12, and The light passes through the hologram layer 3, converges on the reflection film 5 so as to have the smallest diameter, is reflected by the reflection film 5, and passes through the hologram 3 again. The recording reference light 52R that has passed through the optical rotation plate 14R of the two-part optical rotation plate 14 is
B-polarized light is emitted to the information recording medium 1 via the objective lens 12, and after being converged to have the smallest diameter once before the boundary surface between the hologram layer 3 and the protective layer 4,
The light passes through the hologram layer 3 while diverging. Then, in the hologram layer 3, the B-polarized information light 51 </ b> R reflected by the reflective film 5 and the B-polarized recording reference light 52 </ b> R traveling toward the reflective film 5 interfere with each other to form an interference pattern.
When the output of the output light of 0 becomes high, the interference pattern is volumetrically recorded in the hologram layer 3.

As shown in FIGS. 7 and 8, in the present embodiment, the information light and the recording reference light are arranged such that the optical axis of the information light and the optical axis of the recording reference light are arranged on the same line. Are applied to the hologram layer 3 from the same surface side.

In the present embodiment, by performing the recording operation a plurality of times at the same position of the hologram layer 3 while changing the modulation pattern of the recording reference light, phase encoding multiplexing is performed.
It is possible to multiplex-record information in the same place of the hologram layer 3.

Thus, in the present embodiment, a reflection type (Lipman type) hologram is formed in the hologram layer 3. The A-polarized information light 51L and the B-polarized recording reference light 52R do not interfere with each other because their polarization directions are orthogonal to each other. Similarly, the B-polarized information light 51R and the A-polarized recording reference light 52L are Since the polarization directions are orthogonal, there is no interference.
As described above, in the present embodiment, the occurrence of extra interference fringes can be prevented, and a decrease in the signal-to-noise (SN) ratio can be prevented.

In the present embodiment, as described above, the information light is irradiated so as to converge so as to have the smallest diameter on the boundary surface between the hologram layer 3 and the protective layer 4 in the optical information recording medium 1. Then, the light is reflected by the reflection film 5 of the information recording medium 1 and returns to the objective lens 12 side. This return light is incident on the four-divided photodetector 29 in the same manner as in the servo. Therefore, in the present embodiment, it is possible to perform focus servo at the time of recording by using the light incident on the four-divided photodetector 29. The reference light for recording converges so as to have the smallest diameter on the front side of the interface between the hologram layer 3 and the protective layer 4 in the optical information recording medium 1 and becomes divergent light. Even if the light is reflected by the film 5 and returns to the objective lens 12 side, no image is formed on the four-divided photodetector 29.

In the present embodiment, by moving the convex lens 16 back and forth or changing the magnification thereof, the hologram layer 3 is provided with an area where one interference pattern of information light and reference light is recorded volumetrically. The size of the hologram can be arbitrarily determined.

Next, the operation at the time of reproduction will be described with reference to FIG. At the time of reproduction, all the pixels of the spatial light modulator 18 are turned on. Further, the controller 90 supplies the information of the modulation pattern of the recording reference light at the time of recording the information to be reproduced to the phase spatial light modulator 17, and the phase spatial light modulator 17 According to the information, the phase of the passing light is spatially modulated to generate the reference light for reproduction in which the phase of the light is spatially modulated.

The output of the light emitted from the light source device 25 is set to a low output for reproduction. The controller 90 predicts the timing at which the output light of the objective lens 12 passes through the data area 7 based on the basic clock reproduced from the reproduction signal RF, and the output light of the objective lens 12 passes through the data area 7. During this time, the above settings are used. While the light emitted from the objective lens 12 passes through the data area 7, the focus servo and the tracking servo are not performed.
Is fixed.

As shown in FIG. 9, the P-polarized light emitted from the light source device 25 is converted into a parallel light beam by the collimator lens 24, enters the beam splitter 23, and a part of the light amount passes through the semi-reflective surface 23a. Transmit, prism block 1
9 is incident. The light incident on the prism block 19 is
A part of the light amount is reflected by the semi-reflective surface 19b, and the reflected light is reflected by the reflective surface 19a,
7 at that time, according to a predetermined modulation pattern,
The phase of the light is spatially modulated and becomes the reference light for reproduction.
This reproduction reference light becomes light that converges after passing through the convex lens 16. A part of the reproduction reference light is reflected by the semi-reflection surface 15 a of the prism block 15 and passes through the two-rotation optical rotation plate 14. Here, the two-part optical rotation plate 14
The light that has passed through the optical rotation plate 14L has its polarization direction rotated by + 45 ° to become A-polarized light, and the light that has passed through the optical rotation plate 14R has its polarization direction rotated by −45 ° to become B-polarized light.
The reference light for reproduction that has passed through the two-segment optical rotation plate 14 is condensed by the objective lens 12 and irradiates the optical information recording medium 1, and once has the smallest diameter before the boundary surface between the hologram layer 3 and the protective layer 4. After convergence so as to pass, the light passes through the hologram layer 3 while diverging.

FIGS. 10 and 11 are explanatory diagrams showing the state of light during reproduction. In these figures,
The symbol 61 indicates P-polarized light, the symbol 62 indicates S-polarized light, the symbol 63 indicates A-polarized light, and the symbol 64 indicates B-polarized light.

As shown in FIG. 10, the two-part optical rotation plate 14
The reference light 53L for reproduction that has passed through the optical rotation plate 14L becomes A-polarized light, is irradiated to the optical information recording medium 1 via the objective lens 12, and is located on the near side of the boundary surface between the hologram layer 3 and the protective layer 4. , Once converges to the smallest diameter, and then passes through the hologram layer 3 while diverging. As a result, a reproduction light 54L corresponding to the information light 51L during recording is generated from the hologram layer 3. The reproduced light 54L proceeds to the objective lens 12 side, is converted into a parallel light beam by the objective lens 12, passes through the split optical rotation plate 14 again, and becomes S-polarized light.

As shown in FIG. 11, the reproduction reference light 53R passing through the optical rotation plate 14R of the two-part optical rotation plate 14 is used.
Becomes B-polarized light, which is irradiated onto the optical information recording medium 1 via the objective lens 12 and once converges to have the smallest diameter before the boundary surface between the hologram layer 3 and the protective layer 4. The light passes through the hologram layer 3 while diverging. As a result, the information beam 51R at the time of recording is obtained from the hologram layer 3.
Is generated. This reproduction light 54R
Goes to the objective lens 12 side, is converted into a parallel light flux by the objective lens 12, passes through the two-rotation optical rotation plate 14 again, and becomes S-polarized light.

The reproduction light that has passed through the split optical rotation plate 14 enters the prism block 15, and a part of the light amount passes through the semi-reflective surface 15a. The reproduction light transmitted through the semi-reflective surface 15a is reflected by the reflective surface 15a, passes through the spatial light modulator 18, and a part of the light amount is partially reflected by the semi-reflective surface 19 of the prism block 19.
The light reflected by b is incident on the CCD array 20 and is detected by the CCD array 20. On and off patterns are formed on the CCD array 20 by the spatial light modulator 18 during recording, and information is reproduced by detecting these patterns.

When a plurality of information is multiplex-recorded on the hologram layer 3 by changing the modulation pattern of the recording reference light, the same modulation pattern as the modulation pattern of the reproduction reference light among the plurality of information is used. Only the information corresponding to the recording reference light is reproduced.

As shown in FIGS. 10 and 11, in the present embodiment, the irradiation of the reproduction reference light is performed such that the optical axis of the reproduction reference light and the optical axis of the reproduction light are arranged on the same line. Collection of the reproduction light is performed from the same surface side of the hologram layer 3.

In the present embodiment, a part of the reproduction light is incident on the four-divided photodetector 29 like the return light at the time of servo. Therefore, in the present embodiment,
Using the light incident on the four-segment photodetector 29, it is possible to perform focus servo even during reproduction. The reference light for reproduction converges so as to have the smallest diameter before the boundary surface between the hologram layer 3 and the protective layer 4 in the optical information recording medium 1 and becomes divergent light. Even if the light is reflected by the reflection film 5 and returns to the objective lens 12 side, no image is formed on the four-division photodetector 29.

When the two-dimensional pattern of the reproduction light is detected by the CCD array 20, the reproduction light and the CCD
Position the array 20 accurately or use the CCD array 2
It is necessary to recognize the reference position in the reproduction light pattern from the 0 detection data. In the present embodiment, the latter is adopted. Here, referring to FIG. 12 and FIG.
A method of recognizing the reference position in the pattern of the reproduction light from the detection data of the array 20 will be described. FIG.
As shown in (a), the aperture of the pickup 11 is divided by the two-part optical rotation plate 14 into two regions 71L and 71R symmetric about the optical axis. Further, as shown in FIG. 12B, the aperture is divided into a plurality of pixels 72 by the spatial light modulator 18.
The pixel 72 is the minimum unit of the two-dimensional pattern data. In this embodiment, one pixel of digital data “0” or “1” is represented by two pixels, and one of two pixels corresponding to one-bit information is turned on and the other is turned off. If both pixels are on or both off, error data is generated. Expressing 1-bit digital data with two pixels as described above has advantages such as an increase in data detection accuracy by differential detection. FIG.
(A) shows a set 73 of two pixels corresponding to 1-bit digital data. The area where the set 73 exists is hereinafter referred to as a data area. In the present embodiment, 2
Utilizing that error data is obtained when both pixels are on or both off, reference information indicating a reference position in the reproduction light pattern is included in the information light. That is, as shown in FIG. 13B, a cross-shaped area 74 composed of a part having a width of two pixels parallel to the dividing line of the two-part optical rotation plate 14 and a part having a width of two pixels perpendicular to the dividing line.
In addition, the error data is intentionally arranged in a predetermined pattern. This error data pattern is hereinafter referred to as a tracking pixel pattern. This tracking pixel pattern becomes reference position information. In FIG. 13B, reference numeral 75 denotes an ON pixel, and reference numeral 76 denotes an OFF pixel. In addition, the area 77 of four pixels at the center is always turned off.

FIG. 14 shows the tracking pixel pattern and the pattern corresponding to the data to be recorded.
A two-dimensional pattern as shown in FIG. In the present embodiment, among the regions other than the data region, the upper half in the figure is turned off and the lower half is turned on, and pixels in the data region that are in contact with the region other than the data region are other than the data region. It is turned on when the state opposite to the area, that is, the area other than the data area is off, and turned off when the area other than the data area is on. This allows
From the detection data of the CCD array 20, it is possible to more clearly detect the boundary of the data area.

At the time of recording, an interference pattern between the information light and the recording reference light spatially modulated according to the two-dimensional pattern as shown in FIG. The reproduction light pattern obtained during reproduction is shown in FIG.
As shown in (b), the contrast is lower and the SN ratio is lower than during recording. During playback, CC
The D array 20 detects a reproduction light pattern as shown in FIG. 14B and determines data. At this time, a tracking pixel pattern is recognized, and the data is determined using the position as a reference position. .

FIG. 15 (a) conceptually shows the contents of data determined from the reproduction light pattern. In the figure, areas denoted by reference numerals such as A-1-1 represent 1-bit data. In the present embodiment, the data area is
The four regions 78A and 78 are divided by dividing the region 74 of the cross into which the tracking pixel pattern is recorded.
B, 78C and 78D. And FIG.
As shown in (b), the diagonal areas 78A and 78C are combined to form a rectangular area, and similarly, the diagonal areas 78B and 78C are formed.
A rectangular area is formed by combining 78D, and an ECC table is formed by arranging two rectangular areas vertically. The ECC table is a data table formed by adding an error correction code (ECC) such as a CRC (cyclic redundancy check) code to data to be recorded. FIG. 15B shows an example of an ECC table with n rows and m columns, and other arrangements can be freely designed. The data array shown in FIG. 15A uses a part of the ECC table shown in FIG. 15B, and the data array shown in FIG.
Portions of the CC table that are not used in the data array shown in FIG. 15A have a constant value regardless of the data content. At the time of recording, E as shown in FIG.
The CC table is decomposed into four areas 78A, 78B, 78C and 78D as shown in FIG. 15A and recorded on the optical information recording medium 1, and at the time of reproduction, an array as shown in FIG. The data of FIG.
The ECC table as shown in FIG.
Data is reproduced by performing error correction based on the CC table.

The recognition of the reference position (tracking pixel pattern) in the reproduction light pattern as described above and the error correction are performed by the signal processing circuit 89 in FIG.

As described above, according to the optical information recording / reproducing apparatus 10 of the present embodiment, it is possible to multiplex-record information on the optical information recording medium 1 by phase encoding multiplexing, Irradiation of the recording reference light and the information light to the information recording medium 1 and irradiation of the recording reference light to the optical information recording medium 1 and collection of the reproduction light during reproduction are all performed on the same surface side of the optical information recording medium 1. Since it is performed on the same axis, the optical system for recording or reproduction can be made smaller than the conventional holographic recording system, and stray light as in the case of the conventional holographic recording system Problem does not occur. Further, according to the present embodiment, an optical system for recording and reproduction can be configured in the form of a pickup 11 similar to an ordinary optical disk device. Therefore, the optical information recording medium 1
Can be easily accessed at random.

According to the present embodiment, information for performing the focus servo and the tracking servo is recorded on the optical information recording medium 1 so that the focus servo and the tracking servo can be performed using the information. As a result, it is possible to accurately position light for recording or reproduction, and as a result, it is possible to improve the removability, facilitate random access, and increase the recording density, recording capacity, and transfer rate. . In particular, in the recording according to the present embodiment, it is possible to dramatically increase the recording density, the recording capacity, and the transfer rate, in addition to the fact that information can be multiplex-recorded by phase encoding multiplexing. For example, when a series of information is multiplex-recorded at the same position of the hologram layer 3 while changing the modulation pattern of the recording reference light, information can be recorded and reproduced at extremely high speed. .

According to the present embodiment, the information recorded on the optical information recording medium 1 must use the reproduction reference light having the same modulation pattern as that of the recording reference light at the time of recording the information. Can not be reproduced if
Copy protection and confidentiality can be easily realized. Also, according to the present embodiment, the optical information recording medium 1
The optical information recording medium 1 itself is provided at relatively low cost to the user, and various types of information (for example, various types of software) having different modulation patterns of the reference light are recorded therein. It is possible to realize a service in which information of the modulation pattern of the reference light that enables the reproduction of the type of information is individually provided as key information for a fee.

Further, according to the optical information recording / reproducing apparatus 10 according to the present embodiment, the reference position information indicating the reference position in the reproduction light pattern is included in the information light. Recognition becomes easy.

Further, according to the optical information recording / reproducing apparatus 10 according to the present embodiment, the information recorded by the embossed pits on the recording medium is recorded by setting the pickup 11 in the servo state shown in FIG. Since reproduction is possible, compatibility with a conventional optical disk device can be provided.

Further, according to the optical information recording / reproducing apparatus 10 according to the present embodiment, each of the information multiplex-recorded on the optical information recording medium 1 is made to correspond to a modulation pattern of a phase of a different reference light. Therefore, the optical information recording medium 1 on which information is recorded
Is extremely difficult to duplicate. Therefore, illegal duplication can be prevented.

In the optical information recording medium 1 according to the present embodiment, the hologram layer 3 on which information is recorded by using holography is separated from the layer on which information such as addresses is recorded by emboss pits. When the optical information recording medium 1 on which information is recorded is to be copied, these two layers must be made to correspond to each other. From this point, duplication is difficult, and illegal duplication can be prevented.

Next, an optical information recording / reproducing apparatus according to a second embodiment of the present invention will be described. In this embodiment,
This is an example in which multiplex recording can be performed by using both phase encoding multiplexing and hole burning type wavelength multiplexing. The overall configuration of the optical information recording / reproducing apparatus according to the present embodiment is shown in FIG.
Optical information recording and reproducing apparatus 1 according to the first embodiment shown in FIG.
0 is substantially the same as the configuration of FIG.

First, the hole burning type wavelength multiplexing will be briefly described. Hole burning refers to a phenomenon in which a light absorption rate changes at a wavelength position of incident light in a light absorption spectrum, and is also called photochemical hole burning. Hereinafter, a material that causes hole burning, that is, a material that causes a change in light absorption at a wavelength position of incident light in a light absorption spectrum is referred to as a hole burning material. Hole burning materials are generally, such as amorphous,
It is a material in which a light-absorbing center (called a guest) material such as a dye is dispersed in a medium (called a host) having an irregular structure. This hole burning material has a broad light absorption spectrum due to superposition of light absorption spectra of a large number of guests at an extremely low temperature. When such a hole-burning material is irradiated with light of a specific wavelength such as a laser beam (however, a wavelength within the light absorption band of the hole-burning material), only guests having a resonance spectrum corresponding to the wavelength are subjected to photochemical reaction. To a different energy level, a decrease in the light absorptivity occurs at the wavelength position of the irradiated light in the light absorption spectrum of the hole burning material.

FIG. 16 shows a state in which the light absorption spectrum of the hole-burning material has reduced the light absorptance at a plurality of wavelength positions by irradiation with light of a plurality of wavelengths. In the hole burning material, a portion where the light absorptance is reduced by light irradiation is called a hole. Since this hole is extremely small, it is possible to record multiple pieces of information on a hole burning material by changing the wavelength,
Such a multiplex recording method is called hole burning type wavelength multiplexing. Since the hole is about 10 ^-2 nm in size,
It is considered that a hole burning material can provide a multiplicity of about 10 ³ to 10 ⁴ . For a detailed description of hole burning, see, for example, "Basics of Optical Memory", published by Corona, pp. 104-133, 1990,
It is described in the above-mentioned document “Research on a new real-time recording / reproduction of a wavelength multiplexed hologram using PHB”.

In this embodiment, the above-described hole-burning type wavelength division multiplexing is used,
A plurality of holograms can be formed by changing the wavelength. Therefore, in the optical information recording medium 1 used in the optical information recording / reproducing apparatus according to the present embodiment, the hologram layer 3
Is formed of the above-described hole burning material.

In the present embodiment, the light source device 25 in the pickup 11 is assumed to be capable of selectively emitting coherent light of a plurality of wavelengths within the light absorption band of the hole burning material forming the hologram layer 3. I have. As such a light source device 25, a wavelength tunable laser device having a dye laser and a wavelength selection element (prism, diffraction grating, etc.) for selecting the wavelength of the light emitted from the dye laser, or a laser and a light emitted from the laser A wavelength tunable laser device having a wavelength conversion element using a nonlinear optical element for converting a wavelength can be used.

In the present embodiment, the operation section 91 can select the modulation pattern of the reference light from a plurality of modulation patterns, as in the first embodiment.
The wavelength of the light emitted from the light source device 25 can be selected from a plurality of selectable wavelengths. Then, the controller 90 provides the light source device 25 with information on the wavelength selected by itself or the wavelength selected by the operation unit 91 in accordance with a predetermined condition. The light of the wavelength is emitted. Note that the light source device 25 in the present embodiment corresponds to the wavelength selecting means in the present invention.

The other structure of the optical information recording / reproducing apparatus according to this embodiment is the same as that of the first embodiment.

In the optical information recording / reproducing apparatus according to this embodiment,
At the time of recording, the wavelength of the light emitted from the light source device 25 is selected from a plurality of selectable wavelengths. Thereby, the information light and the recording reference light of the selected wavelength are generated. In this embodiment, multiplex recording can be performed by hole burning type wavelength multiplexing by performing a plurality of recording operations at the same location of the hologram layer 3 while changing the wavelengths of the information light and the recording reference light.

In the optical information recording / reproducing apparatus according to the present embodiment, the recording operation is performed a plurality of times at the same position of the hologram layer 3 by changing the modulation pattern of the recording reference light at a certain wavelength. Similarly, by performing a plurality of recording operations by changing the modulation pattern of the recording reference light at the wavelength of, the multiplex recording can be performed using both the phase encoding multiplexing and the hole burning type wavelength multiplexing. In this case, if the degree of multiplexing by phase encoding multiplexing is N and the degree of multiplexing by hole-burning type wavelength multiplexing is M, an N × M degree of multiplexing is obtained. Therefore, according to the present embodiment, it is possible to further increase the recording density, the recording capacity, and the transfer rate as compared with the first embodiment.

According to the present embodiment, the information recorded on the optical information recording medium 1 must use the reproduction reference light having the same wavelength as the information light and the recording reference light at the time of recording the information. Since the data cannot be reproduced, the copy protection and confidentiality can be easily realized as in the first embodiment. Further, when multiplex recording is performed by using both phase encoding multiplexing and hole burning type wavelength multiplexing, the same wavelength as the information light and the recording reference light at the time of recording the information and the recording reference light are used. Since reproduction cannot be performed without using a reproduction reference light having the same modulation pattern as the light modulation pattern, copy protection and confidentiality can be more securely realized.

Further, according to the present embodiment, various types of information having different wavelengths of the information light and the recording reference light or different modulation patterns of the reference light are recorded on the optical information recording medium 1, and the optical information The recording medium 1 itself is provided to the user at a relatively low price, and information on the wavelength of the reference light and the modulation pattern that enables each type of information to be reproduced is individually provided as key information for a fee at the request of the user. Such services can be realized.

Other functions and effects of the present embodiment are the same as those of the first embodiment.

Next, an optical information recording / reproducing apparatus according to a third embodiment of the present invention will be described. The overall configuration of the optical information recording / reproducing apparatus according to the present embodiment is substantially the same as the configuration of the optical information recording / reproducing apparatus 10 according to the first embodiment shown in FIG. However, the configuration of the pickup is different from that of the first embodiment.

FIG. 17 is an explanatory view showing the structure of the pickup in the present embodiment, and FIG. 18 is a plan view showing the structure of an optical unit including each element constituting the pickup.

Pickup 111 in the present embodiment
Is a light source device 112 that emits coherent linearly polarized laser light, a collimator lens 113 arranged in order from the light source device 112 side in the traveling direction of the light emitted from the light source device 112, and an intermediate density filter (neutral density filter).
ity filter; hereinafter, referred to as an ND filter. ) 114, an optical rotation element 115, a polarization beam splitter 116, a phase spatial light modulator 117, a beam splitter 118, and a photodetector 119. Light source device 112
Is designed to emit S-polarized or P-polarized linearly polarized light. The collimator lens 113 is a light source device 1
Twelve outgoing light beams are emitted as parallel light beams. The ND filter 114 has characteristics such that the intensity distribution of the light emitted from the collimator lens 113 is made uniform. The optical element for optical rotation 115 rotates the light emitted from the ND filter 114 to emit light including an S-polarized component and a P-polarized component. As the optical element 115 for optical rotation, for example, a half-wave plate or an optical rotation plate is used. The polarization beam splitter 116 is used for the optical rotation optical element 1.
It has a polarizing beam splitter surface 116a that reflects the S-polarized light component and transmits the P-polarized light component among the fifteen outgoing lights. The phase spatial light modulator 117 is the same as the phase spatial light modulator 17 in the first embodiment. The beam splitter 118 has a beam splitter surface 118a. The beam splitter surface 118a transmits, for example, 20% of the P-polarized light component and reflects 80% of the P-polarized light component. The photodetector 119 monitors the amount of reference light and adjusts the amount of reference light automatically (auto power control).
troll; hereinafter, referred to as APC. ). In the photodetector 119, the light receiving unit may be divided into a plurality of regions so that the intensity distribution of the reference light can be adjusted.

The pickup 111 further includes the light source device 1
A polarization beam splitter 120, a two-part optical rotation plate 121, and a rising mirror 122 are sequentially arranged from the beam splitter 118 side in the direction in which the light from 12 is reflected by the beam splitter surface 118a of the beam splitter 118 and travels. . The polarizing beam splitter 120 includes:
It has a polarizing beam splitter surface 120a that reflects the S-polarized component of the incident light and transmits the P-polarized component.
The two-divided optical rotation plate 121 includes an optical rotation plate 121R disposed on the right side of the optical axis in FIG. 17 and a light rotation plate 121L disposed on the left side of the optical axis in FIG. Rotating plate 121
R and 121L are the same as the optical rotation plates 14R and 14L of the two-part optical rotation plate 14 in the first embodiment, and the optical rotation plate 121R rotates the polarization direction by -45 ° and the optical rotation plate 1R.
21L rotates the polarization direction by + 45 °. The rising mirror 122 is tilted at 45 ° with respect to the optical axis of the light from the split optical rotation plate 121, and reflects the light from the split optical rotation plate 121 in a direction orthogonal to the plane of FIG. It has a reflective surface.

The pickup 111 is further arranged in a direction in which the light from the two-part optical rotation plate 121 is reflected on the reflecting surface of the rising mirror 122 and travels, and the optical information recording medium 1 is fixed to the spindle 81. The optical information recording medium 1
1 and an actuator 124 (see FIG. 1) that can move the objective lens 123 in the thickness direction and the track direction of the optical information recording medium 1.
8).

The pickup 111 further includes the light source device 1
In the direction in which the light from 12 is reflected by the polarizing beam splitter surface 116a of the polarizing beam splitter 116 and travels,
The spatial light modulator 125, the convex lens 126, and the beam splitter 1 arranged in this order from the polarization beam splitter 116 side.
27 and a photodetector 128. The spatial light modulator 125 is similar to the spatial light modulator 18 in the first embodiment. The convex lens 126 has a function of converging the information light on the near side of the recording reference light in the optical information recording medium 1 to form an interference region between the recording reference light and the information light. Further, by adjusting the position of the convex lens 126, the size of the interference area between the recording reference light and the information light can be adjusted. The beam splitter 127 has a beam splitter surface 127a. This beam splitter surface 127a is, for example, S
20% of the polarized light component is transmitted and reflected by 80%. The photodetector 128 is used for monitoring the amount of information light and performing APC of the information light. In this photodetector 128, the light receiving section may be divided into a plurality of regions so that the intensity distribution of the information light can be adjusted. The light that enters the beam splitter 127 from the convex lens 126 side and is reflected by the beam splitter surface 127a enters the polarization beam splitter 120.

The pickup 111 further includes a convex lens 129, a cylindrical lens 130, and a four-segment photodetector 131 which are arranged in this order from the beam splitter 127 side on the opposite side of the beam splitter 127 from the polarization beam splitter 120. The four-segment photodetector 131 is the four-segment photodetector 131 according to the first embodiment.
It is similar to the split photodetector 29. The cylindrical lens 28 is arranged such that the central axis of the cylindrical surface forms an angle of 45 ° with the dividing line of the four-divided photodetector 131.

The pickup 111 further includes an imaging lens 132 and a CCD array 133 which are arranged on the beam splitter 118 on the side opposite to the polarization beam splitter 120 in order from the beam splitter 118 side.

The pickup 111 further includes a collimator lens 134 and a fixing light source device 135 arranged in that order from the polarization beam splitter 116 side on the opposite side of the polarization beam splitter 116 from the spatial light modulator 125.
It has. The fixing light source device 135 emits light for fixing information recorded on the hologram layer 3 of the optical information recording medium 1, for example, ultraviolet light having a wavelength of 266 nm. As such a fixing light source device 135, a laser light source, a light source device that converts the wavelength of light emitted from the laser light source through a nonlinear optical medium, and emits the converted light is used. The collimator lens 134 includes a fixing light source device 135.
Are made into parallel light beams. In this embodiment, the fixing light source device 135 emits S-polarized light.

As shown in FIG. 18, the optical unit 14
0 is provided with an optical unit main body 141. Note that FIG. 18 shows only the bottom surface portion of the optical unit main body 141. The optical unit body 141 includes the above-described collimator lens 113, ND filter 114, optical element for optical rotation 115, polarization beam splitter 116, phase spatial light modulator 117, beam splitter 118, polarization beam splitter 120, split optical rotation plate 121, Launch mirror 1
22, spatial light modulator 125, convex lens 126, beam splitter 127, convex lens 129, cylindrical lens 130, imaging lens 132, and collimator lens 1
34 are attached.

FIG. 18 shows the optical rotation optical element 115 as 1
An example using a / 2 wavelength plate is shown. In this example, the optical rotation optical element 1 is provided in the optical unit main body 141.
In order to adjust the ratio between the S-polarized light component and the P-polarized light component in the 15 outgoing light,
A gear 143 for transmitting the rotation of the output shaft to the optical element 115 for optical rotation is provided.

FIG. 19 shows an example of the optical element for optical rotation 115 using an optical rotation plate. The optical rotation optical element 115 in this example has two wedge-shaped optical rotation plates 115a and 115b facing each other. These optical rotation plates 11
At least one of 5a and 115b is displaced by a driving device (not shown) in the direction of the arrow in FIG.
As shown in (a) and (b), the optical rotation plates 115a, 115
The total thickness of the optical rotation plates 115a and 115b in the portion where 5b overlaps changes. This allows
The angle of rotation of the light passing through the optical rotation plates 115a and 115b changes, and as a result, the ratio of the S-polarized light component to the P-polarized light component in the light emitted from the optical rotation optical element 115 changes. In addition, as shown in FIG.
When the total thickness of the optical rotation plates 15a and 115b is large, the optical rotation angle becomes large, and as shown in FIG.
When the total thickness of 15a and 115b is small, the optical rotation angle becomes small.

The actuator 124 is attached to the upper surface of the optical unit main body 141. Light source device 112
Is integrated with a drive circuit 145 for driving the light source device 112, and together with the drive circuit 145, the unit body 14
It is attached to one side. Photo detector 11
9 is integrated with the APC circuit 146, and is attached to the side surface of the unit main body 141 together with the APC circuit 146. The APC circuit 146 includes the photodetector 11
9 is amplified to generate a signal APC _ref used for APC of the reference light. The photodetector 128 is integrated with the APC circuit 147, and is attached to the side surface of the unit main body 141 together with the APC circuit 147. APC circuit 147 is adapted to amplify the output of the photodetector 119, and generates a signal APC _obj used for APC information light. A signal AP from each of the APC circuits 146 and 147 is provided on a side surface of the unit body 141 near the motor 142.
By comparing C _ref and APC _obj , optical rotation optical element 115
A drive circuit 148 for driving the motor 142 is attached so that the ratio of the S-polarized light component to the P-polarized light component in the outgoing light is in an optimum state.

The four-split photodetector 131 is integrated with the detection circuit 85 (see FIG. 2), and is attached to the side surface of the unit body 141 together with the detection circuit 85. The CCD array 133 is integrated with a signal processing circuit 149 that drives the CCD array 133 and processes an output signal of the CCD array 133, and is mounted on a side surface of the unit body 141 together with the signal processing circuit 149. The fixing light source device 135 includes the fixing light source device 13.
5 is integrated with a drive circuit 150 that drives the drive unit 5, and is mounted on a side surface of the unit body 141 together with the drive circuit 150. An input / output port 151 for inputting / outputting various signals between a circuit in the optical unit 140 and the outside of the optical unit 140 is further attached to a side surface of the unit main body 141. The input / output port 151 is connected to an optical fiber flexible cable 152 including an optical fiber for transmitting a signal using light, for example.

Although not shown, the optical unit body 1
A drive circuit for driving the phase spatial light modulator 117 and a drive circuit for driving the spatial light modulator 125 are attached to the upper surface of 41.

FIG. 20 shows that the light source device 112 emits light in a plurality of wavelength ranges in red (hereinafter, referred to as R) and green (hereinafter, referred to as R).
Indicated as G. ) And blue (hereinafter, referred to as B) laser light of three colors can be emitted.
9 shows an example of the configuration of the pickup 111 in a case where light of three colors of R, G, and B can be detected.

The light source device 112 in the example shown in FIG.
Includes a color combining prism 161. The color combining prism 161 includes an R light incident portion 162R and a G light incident portion 16R.
A 2G / B light incident portion 162B is provided. Each incident part 16
The 2R, 162G, and 162B are provided with correction filters 163R, 163G, and 163B, respectively. The light source device 112 further outputs a semiconductor laser (hereinafter, referred to as an LD) 164R, 1 for emitting R light, G light, and B light, respectively.
64G, 164B and each LD 164R, 164G, 16
4B are converted into parallel luminous fluxes at the respective incident portions 162.
R, 162G, and 162B are provided with collimator lenses 165R, 165G, and 165B. Each LD
R light, G emitted from 164R, 164G, 164B
Light and B light are collimator lenses 165R, 165G, 1
65B, passes through the correction filters 163R, 163G, and 163B, enters the color combining prism 161, is combined by the color combining prism 161, and enters the ND filter 114. In the example shown in FIG. 20,
The collimator lens 113 in FIG. 17 is not provided.

The CCD array 1 in the example shown in FIG.
33 has a color separation prism 171. The color separation prism 171 includes an R light emitting unit 172R, a G light emitting unit 172G, and a B light emitting unit 172B. Correction filters 173R, 173G, 173B are provided in the respective emission units 172R, 172G, 172B.
The CCD array 133 further includes,
2R, 172G, and 172B.
CCD 174 for capturing an R light image, a G light image, and a B light image
R, 174G, and 174B. Imaging lens 1
The light from the 32 side is separated by the color separation prism 171 into R light.
Light, G light, and B light are decomposed into light, G light, and B light.
Correction filters 173R, 173G, 173B, respectively
After that, the light enters the CCDs 174R, 174G, and 174B.

Next, a slide feed mechanism of the optical unit 140 according to the present embodiment will be described with reference to FIGS. 21 is a plan view showing the slide feed mechanism, FIG. 22 is a partially cutaway side view showing the slide feed mechanism in a stationary state, and FIG. 23 is a view showing the slide feed mechanism when the optical unit is slightly displaced. It is a partial cutaway side view.

The slide feed mechanism includes an optical unit 140
Shafts 1 arranged in parallel along the moving direction of
81A, 181B and two for each shaft 181A, 181B.
Bearings 182 movable along the axis, a leaf spring 183 for elastically connecting each bearing 182 and the optical unit 140,
A linear motor 184 for moving the optical unit 140 along the shafts 181A and 181B is provided.

The linear motor 184 is connected to the optical unit 14
0, and two frame-shaped yokes 186A arranged along the moving direction of the optical unit 140 such that a part thereof passes through the coil 185.
186B and a magnet 187 fixed to the inner peripheral portions of the yokes 186A and 186B so as to face the coil 185.
A, 187B.

Here, the operation of the slide feed mechanism will be described. When the linear motor 184 is operated, the optical unit 140 is displaced. When this displacement is small,
As shown in FIG. 23, the leaf spring 183 between the bearing 182 and the optical unit 140 is deformed without displacing the bearing 182. When the displacement of the optical unit 140 exceeds a predetermined range, the bearing 182 is also displaced following the optical unit 140. According to such a slide feed mechanism, when the displacement of the optical unit 140 is small, the bearing 182 is not displaced, so that wear due to sliding of the bearing 182 can be prevented. As a result, it is possible to perform tracking servo by driving the optical unit 140 by the linear motor 184 while ensuring the durability and reliability of the slide feed mechanism. The seek is also performed by the slide feed mechanism.

The actuator 124 is connected to the objective lens 12
3 is provided with a cylindrical actuator main body 182 rotatable about a shaft 181. The actuator body 182 has two holes 1 parallel to the axis 181.
83 are formed. A focusing coil 184 is provided on an outer peripheral portion of the actuator main body 182. Further, a part of the outer periphery of the focusing coil 184 is provided with an in-view access coil (not shown). The actuator 124 further includes a magnet 185 inserted into each of the holes 183 and a magnet (not shown) arranged to face the in-view access coil. The objective lens 123 includes the actuator 12
4, the center of the objective lens 123 and the axis 1
81 are arranged so as to face the track direction.

Next, a method of positioning (servo) the reference light and the information light with respect to the data area of the optical information recording medium 1 according to the present embodiment will be described with reference to FIGS. The actuator 124 according to the present embodiment can move the objective lens 123 in the thickness direction and the track direction of the optical information recording medium 1.

FIGS. 24A to 24C show that the objective lens 123 is moved by the actuator 124 to the optical information recording medium 1.
In the track direction of FIG.
The actuator 124 is in a state shown in FIG. The actuator 124 energizes a not-shown field-of-view access coil, whereby (b)
The state shown is changed to the state shown in (a) or (c). Thus, the objective lens 123
In this embodiment, the operation of moving the image data in the track direction of the optical information recording medium 1 is referred to as in-view access.

FIG. 25 shows the moving direction of the objective lens 123 by seeking and the direction of access within the visual field. In FIG. 25, reference numeral 191 denotes the objective lens 123.
The reference numeral 192 denotes the moving direction of the objective lens 123 due to the access within the visual field. Reference numeral 193 denotes a locus of the center of the objective lens 123 when the movement by the seek and the access in the visual field are used together. In the access within the visual field, the center of the objective lens 123 can be moved by, for example, about 2 mm.

In the present embodiment, the reference light and the information light are positioned (servo) with respect to the data area of the optical information recording medium 1 using the in-field access. FIG.
It is an explanatory view for explaining this positioning. In the optical information recording medium 1 according to the present embodiment, as shown in FIG. 26A, a groove 201 is formed for each track in the address / servo area 6, but in the data area 7, The groove 201 is not formed. Also,
At the end of the address servo area 6, a pit row 202 used for clock reproduction and indicating which of the two ends of the data area 7 is adjacent (referred to as a polarity in the present embodiment). Are formed.

In FIG. 26B, reference numeral 203 denotes a locus of the center of the objective lens 123 during recording or reproduction. In the present embodiment, when information is multiplex-recorded in the data area 7 by phase encoding multiplexing or when information multiplex-recorded in the data area 7 is reproduced,
Without stopping the center of the objective lens 123 in the data area 7, as shown in FIG.
The center of the objective lens 123 is moved using the in-view access so as to reciprocate in a section including a part of the servo area 6. Then, the clock is reproduced using the pit row 202 and the polarity is determined, and in the section 204 in the address servo area 6, focus servo and tracking servo are performed using the groove 201.
Section 20 including data area 7 between sections 204 and 204
In 5, the tracking servo is not performed, and the state at the time of passing the section 204 is maintained. The turn-back position in the movement of the center of the objective lens 123 is determined based on the reproduced clock so as to be a fixed position. Also, the position where the information is multiplex-recorded in the data area 7 is determined based on the reproduced clock so as to be a fixed position. In FIG. 26B, reference numeral 206 represents a gate signal indicating recording or reproduction timing. In this gate signal, when it is at a high (H) level,
It indicates that it is recording or reproduction timing.
In order to multiplex-record information at a predetermined location in the data area 7, for example, the output of the light source device 112 may be selectively set to a high output for recording when the gate signal is at a high level. In order to reproduce the information multiplex-recorded at a predetermined position in the data area 7, for example, light can be selectively emitted from the light source device 112 when the gate signal is at a high level, or a CCD array can be used. When the electronic device 133 has an electronic shutter function, an image may be captured using the electronic shutter function when the gate signal is at a high level.

By performing the positioning of the reference light and the information light in the above-described manner, recording and reproduction can be performed at the same location of the optical information recording medium 1 even when recording and reproduction are performed for a relatively long time. The displacement can be prevented. Further, even when the optical information recording medium 1 is rotating, by performing access within the field of view so as to follow the rotation of the optical information recording medium 1, recording is performed in the same situation as when the optical information recording medium 1 is stationary. And reproduction can be performed, and recording and reproduction can be performed in the same place of the optical information recording medium 1 for a relatively long time. Further, if the technique of positioning the reference light and the information light using the in-field access as described above is used, the disc-shaped optical information recording medium 1 can be used.
The present invention is not limited to this, and it is possible to easily position the reference light and the information light even when using another form of optical information recording medium such as a card.

FIG. 27 shows an example of the locus of the center of the objective lens 123 when a plurality of locations on the optical information recording medium 1 are accessed by using both movement by seek and access within the visual field. In this figure, a vertical straight line represents a seek, a horizontal straight line represents a movement to another portion in a track direction, and a portion performing reciprocating motion within a short section performs recording or reproduction. Represents the part that is.

Next, an example of a cartridge for storing the optical information recording medium 1 will be described with reference to FIGS. FIG. 28 is a plan view of the cartridge, and FIG.
FIG. 4 is a plan view of the cartridge with a shutter opened. In the present embodiment, the cartridge 211 has a window 212 for exposing a part of the optical information recording medium 1 housed therein.
And a shutter 213 for opening and closing the window 212. The shutter 213 is urged in a direction to close the window 212, and normally closes the window 212 as shown in FIG. The optical information recording / reproducing apparatus is moved in a direction in which the window 212 is opened as shown in FIG.

Next, referring to FIGS. 30 to 34, 1
An example of the arrangement of the optical unit 140 when a plurality of pickups 111 are provided in one optical information recording / reproducing apparatus will be described.

FIG. 30 shows an example in which two optical units 140A and 140B are arranged so as to face one surface of the optical information recording medium 1. The optical unit 140A is similar to that of FIG.
1 (hereinafter, A).
Say type. )belongs to. On the other hand, the optical unit 1
40B is a plane-symmetric form (hereinafter, referred to as a B type) with respect to the optical unit 140 shown in FIG. 2
The two optical units 140A and 140B are arranged at positions facing the optical information recording medium 1 exposed through the window 212 of the cartridge 211. Also, each optical unit 140
The slide feed mechanisms A and 140B are arranged such that the center of the objective lens 123 of each of the optical units 140A and 140B moves along a line passing through the center of the optical information recording medium 1.

FIG. 31 shows an example in which two optical units are arranged so as to face each surface of the optical information recording medium 1 and a total of four optical units are provided. FIG.
Is a sectional view taken along line AA 'of FIG. 31, and FIG.
FIG. 4 is a sectional view taken along line -B ′. In this example, the optical information recording medium 1
So as to face one surface (the back surface in FIG. 31) of
The two optical units 140A and 140B are arranged, and the two optical units 140C and 140D are opposed to the other surface (the surface in FIG. 31) of the optical information recording medium 1.
Is arranged. The optical unit 140C is of the A type, and the optical unit 140D is of the B type.

The arrangement of the optical units 140A and 140B and their slide feed mechanisms, and the optical units 140C and 140B
FIG.
As described using 0. In order to effectively use the four optical units 140A, 140B, 140C and 140D, it is necessary to use an optical information recording medium 1 capable of recording and reproducing information from both sides.

FIG. 34 shows an example in which eight optical units are arranged so as to face each surface of the optical information recording medium 1 and a total of 16 optical units are provided. In this example, eight optical units 140 ₁ to 140 ₁ are arranged so as to face one surface (the surface in FIG. 34) of the optical information recording medium 1.
140 ₈ is disposed so as to face the other surface of the optical information recording medium 1 (the back surface in FIG. 34), it is arranged eight optical units 140 _{9-140 16.} The optical unit 140 _1, 140 _3, 140 _5, 140 _7, 14
0 ₁₀ , 140 ₁₂ , 140 ₁₄ , and 140 ₁₆ are of the A type. Optical units 140 ₂ , 140 ₄ , 14
0 _6, 140 _8, 140 _9, 140 _11, 140 _13, 14
0 ₁₅ is of the B type. The slide feed mechanism of each optical unit is arranged such that the center of the objective lens 123 of each optical unit moves along a line passing through the center of the optical information recording medium 1. In order to effectively use the 16 optical units, it is necessary to use an optical information recording medium 1 that is not housed in a cartridge and that can record and reproduce information from both sides.

By the way, in the system including the optical information recording / reproducing apparatus and the optical information recording medium 1 according to the present embodiment,
An extremely large amount of information can be recorded on the optical information recording medium 1 by orders of magnitude, and such a system is suitable for use in recording a huge amount of continuous information. However, in a system used for such a purpose, if information cannot be reproduced while a large amount of continuous information is recorded, the system becomes very difficult to use.

Therefore, as shown in, for example, FIGS. 30 to 34, by providing a plurality of pickups 111 in one optical information recording / reproducing apparatus, recording and reproducing information using one optical information recording medium 1 are performed. Or simultaneously perform recording and reproduction with a plurality of pickups 111, thereby improving the recording and reproduction performance. Can be configured. In addition, one optical information recording / reproducing apparatus has a plurality of pickups 1
Providing 11 makes it possible to greatly improve the performance when searching for desired information from a large amount of information, as compared with the case where only one pickup 111 is provided.

Next, an example of a specific structure of the optical information recording medium 1 according to the present embodiment will be described with reference to FIGS.

Optical information recording medium 1 in the present embodiment
Has a first information layer (hologram layer) on which information is recorded by holography, and a second information layer on which information for servo and address information are recorded by embossed pits or the like. Then, it is necessary to form the interference area between the recording reference light and the information light in the first information layer to a certain size while converging the reference light to have the smallest diameter in the second information layer. Therefore, in the present embodiment, a gap (gap) having a certain size is formed between the first information layer and the second information layer. Thereby, the reference light is converged so as to have the smallest diameter in the second information layer, and the information recorded in the second information layer can be reproduced, while the recording reference light and the information are recorded in the first information layer. The light interference region can be formed to a sufficient size.
The optical information recording medium 1 in the present embodiment can be classified into an air gap type and a transparent substrate gap type according to the method of forming the gap.

FIGS. 35 to 37 show the optical information recording medium 1 of the air gap type. FIG. 35 is a sectional view of a half of the optical information recording medium 1, and FIG. FIG. 37 is a perspective view of a half of the optical information recording medium 1. The optical information recording medium 1 includes a reflective substrate 221 having one surface serving as a reflective surface, a transparent substrate 222 disposed so as to face the reflective surface of the reflective substrate 221, a reflective substrate 221 and a transparent substrate 222. Outer spacer 223 and inner spacer 2 that separate the
24, and a hologram layer 225 bonded to the surface of the transparent substrate 222 on the side of the reflection substrate 221. Between the reflection surface of the reflection substrate 221 and the hologram layer 225,
An air gap having a predetermined thickness is formed. The hologram layer 225 becomes a first information layer. A pregroove is formed on the reflection surface of the reflection substrate 221, and this reflection surface serves as a second information layer.

FIGS. 38 to 40 show the optical information recording medium 1 of the transparent substrate gap type. FIG. 38 is a sectional view of a half of the optical information recording medium 1, and FIG. FIG. 40 is an exploded perspective view, and FIG. 40 is a perspective view of a half of the optical information recording medium 1. The optical information recording medium 1 includes a transparent substrate 231 and a hologram layer 23 serving as a first information layer.
2. The transparent substrate 233 is laminated in this order. On the surface of the transparent substrate 231 opposite to the hologram layer 232, a pre-groove is formed and a reflection film 234 is provided. This transparent substrate 23
1 is opposite to the hologram layer 232,
Information layer. The second information layer and the hologram layer 23
2, a gap having a predetermined thickness is formed by the transparent substrate 231. The transparent substrate 233 is a transparent substrate 2
It is thinner than 31.

Further, the optical information recording medium 1 in the present embodiment can be classified into a single-sided type and a double-sided type.

FIGS. 41 to 43 show a single-sided optical information recording medium 1, FIG. 41 is a cross-sectional view of a 1.2 mm-thick optical information recording medium 1, and FIG. FIG. 4 is a sectional view of an optical information recording medium 1 of 6 mm type,
FIG. 3 is an explanatory diagram showing how the single-sided optical information recording medium 1 is irradiated with the recording reference light and the information light. The optical information recording medium 1 shown in FIG. 41 and FIG.
It has the structure shown in FIG. However, the optical information recording medium 1 shown in FIG.
42 and the total thickness of the transparent substrate 233 are 1.2 mm. In the optical information recording medium 1 shown in FIG. 42, the total thickness of the transparent substrate 231, the hologram layer 232, and the transparent substrate 233 is 0.6 mm. Has become.

The recording reference light 241 emitted from the objective lens 123 to the optical information recording medium 1 converges so as to have the smallest diameter on the surface where the pregroove is formed. Information beam 24 irradiated to
2 converges to have the smallest diameter on the front side of the hologram layer 232. As a result, in the hologram layer 232, an interference area 243 due to the recording reference light 241 and the information light 242 is formed.

Although FIG. 41 and FIG. 42 show the single-sided optical information recording medium 1 of the transparent substrate gap type, the single-sided optical information recording medium 1 of the air gap type may be constituted. In this case, the transparent substrate 22
2. The total thickness of the hologram layer 225 and the air gap is set to 1.2 mm or 0.6 mm.

FIGS. 44 to 46 show a double-sided optical information recording medium 1, FIG. 44 is a sectional view of a transparent substrate gap type optical information recording medium 1, and FIG. 45 is an air gap type optical information recording medium. FIG. 46 is a sectional view of the medium 1, and FIG. 46 is an explanatory diagram showing how to irradiate the double-sided optical information recording medium 1 with the recording reference light and the information light. The optical information recording medium 1 shown in FIG. 44 is of the single-sided type 2 shown in FIG.
The optical information recording medium has a structure in which reflective films 234 are adhered to each other. The optical information recording medium 1 shown in FIG. 45 has a structure in which two single-sided optical information recording media shown in FIG. In the optical information recording medium 1 shown in FIG. 45, the total thickness of the transparent substrate 222 on one side, the hologram layer 225, and the air gap is 0.6 mm.

The recording reference light 241 emitted from the objective lens 123 to the optical information recording medium 1 converges so as to have the smallest diameter on the surface on which the pregroove is formed. Information beam 24 irradiated to
2 converges to have the smallest diameter on the front side of the hologram layers 232 and 225. As a result, the hologram layer 2
32, 225, the recording reference light 241 and the information light 2
Thus, an interference region 243 is formed.

By the way, the optical information recording / reproducing apparatus according to the present embodiment is also capable of recording and reproducing information using a conventional optical disk. For example, as shown in FIG. 47, when using a single-sided optical disk 251 in which a pregroove is formed on one surface of a transparent substrate 252 and a reflection film 253 is provided, as shown in FIG.
Light emitted from the objective lens 123 to the optical disk 251 is converged so that the optical disk 251 has the smallest diameter on the surface of the optical disk 251 where the pregroove is formed, that is, the information layer. In the optical disc 251 shown in FIG. 47, the thickness of the transparent substrate 252 is, for example, 1.2 mm. As an optical disk having a structure as shown in FIG.
CD, CD-ROM, CD-R (Write Once
Once) CDs and MDs (minidiscs).

Also, as shown in FIG. 49, a pre-groove is formed on one side and a reflection film 263 is provided.
When using a double-sided optical disk 261 having a structure in which a plurality of transparent substrates 262 are adhered to each other with a reflective film 263, as shown in FIG. Are converged so as to have the smallest diameter in the surface where the pregroove is formed, that is, in the information layer. In the optical disk 261 shown in FIG.
Is 0.6 mm, for example. As the optical disk having the structure as shown in FIG.
M, DVD-RAM, MO (magneto-optical) disk, and the like.

In the optical information recording medium 1 according to the present embodiment, the second information layer is the same as the information layer of a conventional optical disk as shown in FIGS. A similar form can be adopted. In this case, the information recorded on the second information layer can be reproduced by setting the pickup 111 to the state at the time of servo. Further, since information and address information for servo are also recorded in the information layer of the conventional optical disc, the second information layer is formed in the same form as the information layer of the conventional optical disc, thereby making it possible to use the conventional optical disc. Servo information and address information recorded in the information layer can be used as is for positioning the information light, recording reference light and reproduction reference light for recording and reproduction in the hologram layer. Becomes A second information layer (an information layer in a conventional optical disc);
In addition, the application range of the second information layer is wide such that high-speed search can be performed by recording directory information, directory management information, and the like of information recorded on the first information layer (hologram layer).

Next, before describing the operation of the optical information recording / reproducing apparatus according to the present embodiment, FIGS.
, The principle of phase encoding multiplexing will be described.
FIG. 51 is a perspective view showing a schematic configuration of a general recording / reproducing system that performs phase encoding multiplexing. This recording / reproducing system has two
Spatial light modulator 301 for generating information light 302 based on two-dimensional digital pattern information, and spatial light modulator 301
From the hologram recording medium 3
A reference light 305 having a phase spatially modulated and a lens 303 irradiating the reference light 305
A spatial light modulator 304 that irradiates the hologram recording medium 300 with light from a direction substantially orthogonal to the information light 302,
A CCD array 308 for detecting the reproduced two-dimensional digital pattern information, and a reproduction light 306 emitted from the hologram recording medium 300 are condensed to form a CCD array 30.
And a lens 307 for irradiating the light onto the light source 8.

In the recording / reproducing system shown in FIG. 51, at the time of recording, information such as an original image to be recorded is digitized, and a signal of 0 or 1 is further arranged two-dimensionally to obtain two-dimensional digital pattern information (hereinafter, referred to as "data"). Page data).
Here, it is assumed that page data # 1 to #n are multiplex-recorded on the same hologram recording medium 300. Also, two-dimensional digital pattern information for phase modulation (hereinafter, referred to as phase data) # which differs for each of the page data # 1 to #n.
1 to #n are generated. First, at the time of recording the page data # 1, the spatial light modulator 30 is recorded based on the page data # 1.
1 generates a spatially modulated information beam 302 and irradiates the hologram recording medium 300 via a lens 303. At the same time, the reference light 305 whose phase is spatially modulated is generated by the phase spatial light modulator 304 based on the phase data # 1, and is applied to the hologram recording medium 300. As a result, interference fringes formed by the superposition of the information beam 302 and the reference beam 305 are recorded on the hologram recording medium 300. Hereinafter, similarly, page data #
When recording data # 2 to #n, page data # 2 to #n respectively
Based on #n, information light 302 spatially modulated by spatial light modulator 301 is generated, and phase data # 2
Based on #n, the reference spatial light modulator 304 generates reference light 305 whose phase is spatially modulated, and irradiates the hologram recording medium 300 with these information light 302 and reference light 305. In this manner, a plurality of pieces of information are multiplex-recorded at the same location on the hologram recording medium 300. A hologram in which information is multiplex-recorded is called a stack. In the example shown in FIG. 51, the hologram recording medium 300 has a plurality of stacks (stack 1, stack 2,..., Stack m,...).

To reproduce any page data from the stack, the reference beam 305 whose phase is spatially modulated based on the same phase data as when the page data was recorded.
May be applied to the stack. Then,
The reference light 305 is selectively diffracted by interference fringes corresponding to the phase data and the page data, and a reproduction light 306 is generated. The reproduction light 306 is transmitted through a lens 307
Through the CCD array 308, and the two-dimensional pattern of the reproduction light is detected by the CCD array 308. Then, the information such as the original image is reproduced by decoding the detected two-dimensional pattern of the reproduction light in a manner reverse to that at the time of recording.

FIG. 52 shows how interference fringes are formed on the hologram recording medium 300 by interference between the information beam 302 and the reference beam 305. In FIG. 52,
(A) is an information beam 302 based on page data # 1.
₁ and, by interference of the reference light 305 ₁ based on the phase data # 1, shows how the interference fringes 309 ₁ is formed. Similarly, (b) shows an information beam 302 ₂ based on page data # 2 and a reference beam 305 ₂ based on phase data # 2.
Interference by, shows how the interference fringes 309 ₂ is formed of, (c), the information light 302 based on the page data # 3
_3, by the interference of the reference light 305 ₃ based on the phase data # 3, shows how the interference fringes 309 ₃ is formed.

Next, the operation of the optical information recording / reproducing apparatus according to the present embodiment will be described in the order of servo, recording and reproduction.

First, the operation at the time of servo will be described with reference to FIGS. 53 and 54. FIG. 53 is an explanatory diagram showing the state of the pickup 111 during servo. At the time of servo, all the pixels of the spatial light modulator 125 are cut off. The phase spatial light modulator 117 is set such that the light passing through each pixel has the same phase. The output of the light emitted from the light source device 112 is set to a low output for reproduction. The controller 90 predicts the timing at which the light emitted from the objective lens 123 passes through the address servo area 6 based on the basic clock reproduced from the reproduction signal RF, and outputs the light emitted from the objective lens 123 into the address servo area. During the passage through 6, the above settings are made.

The light emitted from the light source device 112 is converted into a parallel light beam by the collimator lens 113, passes through the ND filter 114 and the optical rotation element 115 in order, and is incident on the polarization beam splitter 116. The S-polarized light component of the light that has entered the polarization beam splitter 116 is reflected by the polarization beam splitter surface 116 a and cut off by the spatial light modulator 125. Polarization beam splitter 11
The P-polarized light component of the light incident on 6 passes through the polarization beam splitter surface 116a, passes through the phase spatial light modulator 117, and is incident on the beam splitter 118. Part of the light incident on the beam splitter 118 is reflected by the beam splitter surface 118a, and
After passing through 0, the light enters the two-part optical rotation plate 121. Here, light that has passed through the optical rotation plate 121R of the split optical rotation plate 121 becomes B-polarized light, and light that has passed through the optical rotation plate 121L becomes A-polarized light. The light that has passed through the two-part optical rotation plate 121 is reflected by the rising mirror 122, condensed by the objective lens 123, and converges on the pre-groove in the optical information recording medium 1, which is deeper than the hologram layer. Then, the information recording medium 1 is irradiated. This light is reflected on the pre-groove. At that time, the light is modulated by pits formed on the pre-groove and returns to the objective lens 123 side. In FIG. 53, the rising mirror 122 is omitted.

The return light from the information recording medium 1 is converted into a parallel light beam by the objective lens 123, passes through the split optical rotation plate 121, and becomes S-polarized light. This return light is reflected by the polarization beam splitter surface 120a of the polarization beam splitter 120, enters the beam splitter 127, partially transmits through the beam splitter surface 127a, and passes through the convex lens 129 and the cylindrical lens 130 in order. , Detected by the four-segment photodetector 131. And
Based on the output of the four-segment photodetector 131,
The detection circuit 85 generates a focus error signal FE, a tracking error signal TE, and a reproduction signal RF. Based on these signals, focus servo and tracking servo are performed, and reproduction of a basic clock and determination of an address are performed. .

A part of the light incident on the beam splitter 118 is incident on the photodetector 119, and a signal _APCref is generated by the APC circuit 146 based on the output signal of the photodetector 119. Then, based on the signal APC _ref , the optical information recording medium 1
APC is performed so that the amount of light applied to the light source becomes constant. More specifically, as the signal APC _ref equals a predetermined value, the drive circuit 148 drives the motor 142 to adjust the rotating optical element 115. Alternatively, at the time of servo, the optical rotation optical element 115 may be set so that the light passing through the optical rotation optical element 115 becomes only the P-polarized component, and the output of the light source device 112 may be adjusted to perform APC. . If the light receiving section of the photodetector 119 is divided into a plurality of regions, and the phase spatial light modulator 117 can also adjust the amount of transmitted light, the phase of the light is adjusted based on the output signal of each light receiving section of the photodetector 119. The amount of transmitted light for each pixel in the spatial light modulator 117 may be adjusted so that the intensity distribution of light applied to the optical information recording medium 1 is adjusted to be uniform.

In the above setting at the time of servo,
The configuration of the pickup 111 is the same as the configuration of a recording / reproducing pickup for an ordinary optical disk. Therefore, the optical information recording / reproducing apparatus in the present embodiment can perform recording and reproduction using a normal optical disk.

FIG. 54 is an explanatory diagram showing the state of light near the optical disk when recording and reproduction are performed using an ordinary optical disk by the optical information recording / reproducing apparatus according to the present embodiment. In this figure, a double-sided optical disk 261 is given as an example of a normal optical disk. In this optical disc 261, a pregroove 265 is formed on the surface of the transparent substrate 262 on the side of the reflective film 263, and light from the objective lens 123 is irradiated onto the optical disc 261 so as to converge on the pregroove 265. The light is modulated by the pits formed on the pre-groove 265 and returns to the objective lens 123 side.

Next, an operation at the time of recording will be described with reference to FIGS. FIG. 55 is an explanatory diagram showing the state of the pickup 111 during recording, and FIGS. 56 and 57 are explanatory diagrams respectively showing the state of light near the optical information recording medium 1 during recording. In the following,
As shown in FIG. 56, an example in which an air gap type optical information recording medium 1 is used will be described.

At the time of recording, the spatial light modulator 125 selects a transmissive state (hereinafter, also referred to as “on”) and a cut-off state (hereinafter, also referred to as “off”) for each pixel according to information to be recorded, and passes. The information light is spatially modulated to generate information light. The phase spatial light modulator 117 controls the passing light
The phase of light is spatially modulated by selectively giving a phase difference of 0 (rad) or π (rad) with respect to a predetermined phase for each pixel according to a predetermined modulation pattern. A recording reference beam whose phase is spatially modulated is generated.

In the present embodiment, as described above,
When information is multiplexed and recorded in the data area 7 by phase encoding multiplexing, the center of the objective lens 123 is positioned in the data area 7.
The center of the objective lens 123 is moved using the in-view access so as to reciprocate in a section including the part of the address servo area 6 on both sides thereof. Objective lens 12
When the center of 3 comes to a predetermined position in the data area 7, the output of the light source device 112 is selectively set to a high output for recording.

The light emitted from the light source device 112 is converted into a parallel light beam by the collimator lens 113, passes through the ND filter 114 and the optical rotation element 115 in order, and is incident on the polarization beam splitter 116. The P-polarized light component of the light incident on the polarizing beam splitter 116 passes through the polarizing beam splitter surface 116a and passes through the phase spatial light modulator 117. At that time, the phase of the light is spatially modulated, and the recording is performed. Reference light. This recording reference light is incident on the beam splitter 118. Beam splitter 11
A part of the recording reference light incident on 8 is reflected on the beam splitter surface 118a, passes through the polarization beam splitter 120, and is incident on the two-part optical rotation plate 121. Where 2
The recording reference light that has passed through the optical rotation plate 121R of the split optical rotation plate 121 becomes B-polarized light, and the recording reference light that has passed through the optical rotation plate 121L becomes A-polarized light. The recording reference light that has passed through the two-part optical rotation plate 121 is reflected by the rising mirror 122,
The light is condensed by the objective lens 123 and irradiates the optical information recording medium 1 so as to converge on the optical information recording medium 1 on the back side of the hologram layer 225. In FIG. 55, the rising mirror 122 is omitted.

On the other hand, the S-polarized light component of the light incident on the polarization beam splitter 116 is reflected by the polarization beam splitter surface 116a, passes through the spatial light modulator 125, and at that time, spatially changes according to the information to be recorded. Modulated to
It becomes information light. This information light is transmitted to the beam splitter 127.
Incident on. Part of the information light incident on the beam splitter 127 is reflected by the beam splitter surface 127a, and is reflected by the beam splitter surface 120 of the polarization beam splitter 120.
The light is reflected by a and enters the two-segment optical rotation plate 121. Here, the information light passing through the optical rotation plate 121R of the two-part optical rotation plate 121 becomes A-polarized light, and the information light passing through the optical rotation plate 121L becomes B-polarized light. The information light that has passed through the split optical rotation plate 121 is reflected by the rising mirror 122 and
The light is condensed by the optical information recording medium 23, and is irradiated onto the optical information recording medium 1 so as to pass through the hologram layer 225 while being converged and diffused on the near side of the hologram layer 225 in the optical information recording medium 1.

As a result, as shown in FIG. 56, in the hologram layer 225, the recording reference light 311 and the information light 3
12 form an interference region 313. The interference area 313 has a barrel shape. As shown in FIG. 55, by adjusting the position 310 of the convex lens 126, the convergence position of the information light can be adjusted.
13 can be adjusted.

As shown in FIG. 57, the hologram layer 22
5, the A-polarized recording reference light 311A that has passed through the optical rotation plate 121L of the two-part optical rotation plate 121 and the two-part optical rotation plate 1
A-polarized information light 312 that has passed through 21 optical rotation plates 121R
A interferes with A, and B-polarized recording reference light 311B that has passed through the optical rotation plate 121R of the 2-split optical rotation plate 121 and B-polarized information light 3 that has passed through the optical rotation plate 121L of the 2-split optical rotation plate 121.
12B, and these interference patterns are volumetrically recorded in the hologram layer 225.

Also, by changing the modulation pattern of the phase of the recording reference light for each piece of information to be recorded, a plurality of pieces of information can be multiplex-recorded at the same location on the hologram layer 225.

By the way, as shown in FIG. 55, a part of the recording reference light incident on the beam splitter 118 is incident on the photodetector 119, and based on the output signal of the photodetector 119, the APC circuit 146 outputs the signal APC. _ref is generated. A part of the information light incident on the beam splitter 127 is incident on the photodetector 128, and based on the output signal of the photodetector 128, the signal APC is output by the APC circuit 147.
_obj is generated. And these signals APC _ref ,
APC is performed based on the APC _{obj such} that the ratio of the intensity of the recording reference light and the intensity of the information light applied to the optical information recording medium 1 becomes an optimal value. Specifically, the driving circuit 148
The signals APC _ref and APC _obj are compared, and the optical rotation optical element 115 is adjusted by driving the motor 142 such that these signals have a desired ratio. If the light receiving section of the photodetector 119 is divided into a plurality of regions, and the phase spatial light modulator 117 can also adjust the amount of transmitted light, the phase of the light is adjusted based on the output signal of each light receiving section of the photodetector 119. The transmitted light amount for each pixel in the spatial light modulator 117 may be adjusted so that the intensity distribution of the recording reference light applied to the optical information recording medium 1 becomes uniform. Similarly, when the light receiving portion of the photodetector 128 is divided into a plurality of regions, and the spatial light modulator 125 can also adjust the amount of transmitted light, the light receiving portion of the photodetector 128 is controlled based on the output signal of each light receiving portion. Alternatively, the transmitted light amount of each pixel in the spatial light modulator 125 may be adjusted so that the intensity distribution of the information light applied to the optical information recording medium 1 is adjusted to be uniform.

In the present embodiment, the signal AP
APC is performed based on the sum of C _ref and APC _obj such that the total intensity of the recording reference light and the information light has an optimum value. As a method of controlling the total intensity of the recording reference light and the information light, control of the peak value of the output of the light source device 112,
There is control of an emission pulse width in the case of emitting light in a pulsed manner, a temporal profile of the intensity of the emitted light, and the like.

Next, an operation at the time of fixing will be described with reference to FIGS. FIG. 58 is an explanatory diagram showing the state of the pickup 111 during fixing, and FIG.
FIG. 3 is an explanatory diagram illustrating a state of light near an optical information recording medium 1 during fixing. At the time of fixing, the spatial light modulator 125
All pixels are turned off. Phase spatial light modulator 117
Is set so that all the lights passing through each pixel have the same phase. No light is emitted from the light source device 112, and S-polarized ultraviolet light for fixing is emitted from the fixing light source device 135.

The light emitted from the fixing light source device 135 is converted into a parallel light beam by the collimator lens 134.
The light enters the polarization beam splitter 116, is reflected by the polarization beam splitter surface 116a, and is reflected by the phase spatial light modulator 117.
And enters the beam splitter 118. Part of the light incident on the beam splitter 118 is reflected by the beam splitter surface 118a, and
After passing through 20, the light enters the two-part optical rotation plate 121. Here, light that has passed through the optical rotation plate 121R of the split optical rotation plate 121 becomes B-polarized light, and light that has passed through the optical rotation plate 121L becomes A-polarized light. The light that has passed through the two-part optical rotation plate 121 is reflected by the rising mirror 122, condensed by the objective lens 123, and condensed by the hologram layer 2 in the optical information recording medium 1.
The information recording medium 1 is irradiated so as to converge on a pre-groove located deeper than 25. The light fixes the interference pattern formed in the interference region 313 in the hologram layer 225. In FIG. 58, the rising mirror 122 is omitted.

The positioning (servo) of the fixing light with respect to the optical information recording medium 1 can be performed in the same manner as the positioning of the recording reference light and the information light during recording.

A part of the fixing light incident on the beam splitter 118 is incident on the photodetector 119, and a signal _APCref is generated by the APC circuit 146 based on the output signal of the photodetector 119. Then, based on the signal APC _ref , APC is performed so that the amount of fixing light applied to the optical information recording medium 1 becomes constant. Specifically, the signal APC _ref
Is fixed to be equal to a predetermined value.
Adjust the output of. The light receiving section of the photodetector 119 is divided into a plurality of regions, and the phase spatial light modulator 117
If the optical information recording medium 1 can also adjust the amount of transmitted light, the amount of transmitted light for each pixel in the phase spatial light modulator 117 is adjusted based on the output signal of each photodetector of the photodetector 119. May be adjusted so that the intensity distribution of the fixing light radiated to the surface becomes uniform.

Next, an operation at the time of reproduction will be described with reference to FIGS. FIG. 60 is an explanatory diagram showing the state of the pickup 111 during reproduction, and FIGS. 61 and 62 are explanatory diagrams showing the state of light near the optical information recording medium 1 during reproduction, respectively.

During reproduction, all the pixels of the spatial light modulator 125 are cut off. The phase spatial light modulator 117 applies a phase difference of 0 (rad) or π to the passing light based on a predetermined phase for each pixel according to a predetermined modulation pattern.
By selectively giving (rad), the phase of the light is spatially modulated to generate the reference light for reproduction in which the phase of the light is spatially modulated. Here, in the present embodiment, the phase modulation pattern of the reproduction reference light is the phase spatial light modulator 11.
7, the pattern is point-symmetric with respect to the modulation pattern of the phase of the recording reference light when information to be reproduced is recorded.

The light emitted from the light source device 112 is converted into a parallel light beam by the collimator lens 113, passes through the ND filter 114 and the optical rotation element 115 in order, and is incident on the polarization beam splitter 116. The S-polarized light component of the light that has entered the polarization beam splitter 116 is reflected by the polarization beam splitter surface 116 a and cut off by the spatial light modulator 125. Polarization beam splitter 11
The P-polarized light component of the light incident on the reference light 6 passes through the polarization beam splitter surface 116a and passes through the phase spatial light modulator 117. At this time, the phase of the light is spatially modulated, and the reproduction reference light is used. Becomes This reference light for reproduction is incident on the beam splitter 118. A part of the reference light for reproduction that has entered the beam splitter 118 is
Reflected by the polarizing beam splitter 120,
The light enters the two-part optical rotation plate 121. Here, the reproduction reference light that has passed through the optical rotation plate 121R of the two-piece optical rotation plate 121 is B-polarized light, and the reproduction reference light that has passed through the optical rotation plate 121L is A.
It becomes polarized light. The reference light for reproduction that has passed through the two-segment optical rotation plate 121 is reflected by the rising mirror 122, condensed by the objective lens 123, and converges on the optical information recording medium 1 behind the hologram layer 225. Irradiates the optical information recording medium 1. In FIG. 60, the rising mirror 122 is omitted.

The positioning (servo) of the reproduction reference beam with respect to the optical information recording medium 1 can be performed in the same manner as the positioning of the recording reference beam and the information beam during recording.

As shown in FIG. 62, the split optical rotation plate 12
B-polarized reproduction reference light 3 that has passed through the first optical rotation plate 121R
15B passes through the hologram layer 225, is reflected by the reflection surface at the convergence position on the back side of the hologram layer 225, and passes through the hologram layer 225 again. At this time, the reference light for reproduction 315B after being reflected by the reflection surface passes through the portion irradiated with the reference light for recording 311A at the time of recording in the interference area 313, and has the same modulation pattern as the reference light for recording 311A. It has become light. Therefore, the reference light for reproduction 31
Due to 5B, a reproduction light 316B corresponding to the information light 312A at the time of recording is generated from the interference area 313. The reproduction light 316B travels to the objective lens 123 side.

Similarly, the optical rotation plate 12 of the two-part optical rotation plate 121
The A-polarized reproduction reference light 315A that has passed through 1L passes through the hologram layer 225, is reflected by the reflection surface at the convergence position on the back side of the hologram layer 225, and passes through the hologram layer 225 again. At this time, the reproduction reference light 315A after being reflected by the reflection surface passes through the portion irradiated with the recording reference light 311B at the time of recording in the interference area 313, and has the same modulation pattern as the recording reference light 311B. It has become light. Therefore, by this reference beam for reproduction 315A,
From the interference area 313, a reproduction light 316A corresponding to the information light 312B at the time of recording is generated. This reproduction light 316
A advances to the objective lens 123 side.

The B-polarized reproduction light 316B is
23, the optical rotation plate 121 of the two-part optical rotation plate 121
After passing through R, the light becomes P-polarized light. A-polarized reproduction light 31
6A, after passing through the objective lens 123, passes through the optical rotation plate 121L of the two-segment optical rotation plate 121, and becomes P-polarized light. The reproduction light that has passed through the split optical rotation plate 121 enters the polarization beam splitter 120, passes through the polarization beam splitter surface 120 a, and enters the beam splitter 118. Part of the reproduction light that has entered the beam splitter 118 passes through the beam splitter surface 118a, passes through the imaging lens 132, and enters the CCD array 133. As shown in FIG. 60, by adjusting the position of the imaging lens 132, it is possible to adjust the imaging state of the reproduction light on the CCD array 133.

On and off patterns by the spatial light modulator 125 during recording are imaged on the CCD array 133, and information is reproduced by detecting these patterns. When a plurality of pieces of information are multiplex-recorded on the hologram layer 225 by changing the modulation pattern of the recording reference light, among the plurality of pieces of information, a modulation pattern that is point-symmetric to the modulation pattern of the reproduction reference light is used. Only the information corresponding to the recording reference light is reproduced.

A part of the reference light for reproduction that has entered the beam splitter 118 enters the photodetector 119, and a signal _APCref is generated by the APC circuit 146 based on the output signal of the photodetector 119. Then, based on the signal APC _ref , APC is performed so that the amount of the reference light for reproduction applied to the optical information recording medium 1 becomes constant. Specifically, the signal APC
_The drive circuit 148 drives the motor 142 to adjust the optical rotation element 115 so that _ref becomes equal to a predetermined value. Alternatively, at the time of reproduction, the optical rotation element 115 may be set so that the light passing through the optical rotation element 115 becomes only the P-polarized component, and the output of the light source device 112 may be adjusted to perform APC. . Photo detector 11
9 is divided into a plurality of regions, and if the phase spatial light modulator 117 is also capable of adjusting the amount of transmitted light, the phase spatial light modulator 117 outputs a phase spatial light based on the output signal of each light receiving unit of the photodetector 119. The amount of transmitted light for each pixel in the optical modulator 117 may be adjusted so that the intensity distribution of the reproduction reference light applied to the optical information recording medium 1 becomes uniform.

Further, in the present embodiment, the light source device 1
12 is a device capable of emitting laser beams of three colors of R, G, and B, and the CCD array 133 is a device capable of detecting light of three colors of R, G, and B. Medium 1
By using a hologram layer having three hologram layers whose optical characteristics change only by light of each color of R, G and B, the same modulation pattern of the reference light for recording is used and the same It is possible to record three types of information in a location, and it is possible to multiplex-record more information. As a recording medium having the three hologram layers as described above, for example, DuPont H
There is RF-700X059-20 (trade name).

As described above, when information is multiplex-recorded by light of three colors of R, G, and B, the same portion of the optical information recording medium 1 is provided for each of the R, G, and B colors. Information is recorded in a time-division manner. At this time, the modulation pattern of the information light is changed for each of R, G, and B colors, but the modulation pattern of the recording reference light is not changed. Here, each pixel of the information light for each color is 2
When value information is carried, that is, when each pixel is represented by light or dark, by performing multiplex recording of information by light of three colors of R, G, and B, for example, R is set to the MSB (most significant bit). Bit) and B as LSB (least significant bit), it is possible to record information of 8 (= 2 ³ ) values for each pixel. When the spatial light modulator 125 can adjust the amount of transmitted light to three or more levels and each pixel of the information light for each color carries n (n is an integer of 3 or more) gradation information, R, G, B By performing multiplexed recording of information using the three colors of light, it becomes possible to record n ³ value information for each pixel.

In the case where information is multiplex-recorded with light of three colors of R, G and B, the information can be reproduced in various ways as follows. That is, the reference light for reproduction is R,
If light of any one of G and B is used, only information recorded using light of the same color as the reference light for reproduction is reproduced. When the reproduction reference light is light of any two colors of R, G, and B, only two types of information recorded using the same two colors of light as the reproduction reference light are reproduced. . These two types of information are separated into information for each color in the CCD array 133. When the reference light for reproduction is light of three colors of R, G, and B, all three types of information recorded using the light of three colors are reproduced. The three types of information are separated into information for each color in the CCD array 133. In addition,
When the optical information recording medium 1 has layers for each color of R, G, and B, multiplex recording is performed on each layer for each color by phase encoding multiplexing. Thereby, there is an effect that a reproduced image of a pattern for each of R, G, and B colors can be obtained for each modulation pattern of the phase of the reference light.

Next, referring to FIGS. 63 and 64, the direct read-after-write (Direct Rrad After Write) of the optical information recording / reproducing apparatus according to the present embodiment will be described.
Hereinafter, referred to as DRAW. ) Function and write power control at the time of multiplex recording (Write Power Control;
Hereinafter, it is described as WPC. The function will be described.

First, the DRAW function will be described.
The DRAW function is a function for reproducing the recorded information immediately after recording the information. With this function, it is possible to verify the recorded information immediately after recording the information.

Referring to FIGS. 55 and 57, the principle of the DRAW function in the present embodiment will be described. First, in the present embodiment, when the DRAW function is used, the modulation pattern of the recording reference light is a point-symmetric pattern with respect to the center of the phase spatial light modulator 117. At the time of recording, in the hologram layer 225, the reference light 311A for recording A-polarized light that has passed through the optical rotation plate 121L of the two-part optical rotation plate 121, and the optical rotation plate 121R of the two-part optical rotation plate 121
And the reference light 311B for B-polarized light that has passed through the optical rotation plate 121R of the 2-split optical rotation plate 121 and the A-polarized information beam 312A that has passed through the optical rotation plate 121R of the 2-split optical rotation plate 121.
The information light 312B of B-polarized light that has passed through 1L interferes, and these interference patterns are volumetrically recorded in the hologram layer 225.

As described above, when the interference pattern starts to be recorded in the hologram layer 225, the A-polarized recording reference light 311A that has passed through the optical rotation plate 121L of the two-divided optical rotation plate 121.
Is reflected by the reflection surface located at the convergence position on the back side of the hologram layer 225, and A-polarized reproduction light is generated from the position where the interference pattern is recorded by the recording reference light 311B. This reproduction light travels to the objective lens 123 side,
After passing through the objective lens 123, the light passes through the optical rotation plate 121L of the two-divided optical rotation plate 121 and becomes P-polarized light. Similarly, B passing through the optical rotation plate 121R of the two-part optical rotation plate 121
The B-polarized reproduction light is generated from the position where the interference pattern is recorded by the recording reference light 311A due to the light reflected by the recording reference light 311B on the reflection surface at the convergence position on the back side of the hologram layer 225. . The reproduction light travels to the objective lens 123 side, passes through the objective lens 123, passes through the optical rotation plate 121R of the two-part optical rotation plate 121, and becomes P-polarized light. The reproduction light that has passed through the split optical rotation plate 121 enters the polarization beam splitter 120, passes through the polarization beam splitter surface 120 a, and enters the beam splitter 118. Part of the reproduction light that has entered the beam splitter 118 passes through the beam splitter surface 118a, passes through the imaging lens 132, and passes through the CCD array 13
3 and is detected. Thus, the recorded information can be reproduced immediately after the recording of the information.

In FIG. 63, reference numeral 321 indicates an example of the relationship between the elapsed time after the start of recording information at one location on the optical information recording medium 1 and the output level of the CCD array 133. As described above, the output level of the CCD array 133 gradually increases in accordance with the degree of recording of the interference pattern on the optical information recording medium 1 after the start of information recording, reaches a maximum value at a certain time, and thereafter,
It gets smaller gradually. It can be said that the higher the output level of the CCD array 133, the higher the diffraction efficiency due to the recorded interference pattern (hereinafter, referred to as a recording pattern). Therefore, by stopping recording when the output level of the CCD array 133 reaches an output level corresponding to a desired diffraction efficiency during recording, a recording pattern having a desired diffraction efficiency can be formed.

In the present embodiment, preferably, a test area is appropriately provided on the optical information recording medium 1 in order to form a recording pattern having a desired diffraction efficiency by using the DRAW function as described above. The test area is the data area 7
Similarly to the above, it is an area where information can be recorded by holography. Preferably, the controller 90 performs the following operation when recording information. That is, the controller 90 performs an operation of recording predetermined test data in the test area in advance, and detects a profile of the output level of the CCD array 133 as shown in FIG. At this time, it is preferable to change the output of the light source device 112 or the ratio of the amount of light between the recording reference light and the information light to record test data and adjust the output level of the CCD array 133 at a plurality of locations in the test area. A profile detection operation is performed. For example, in FIG.
As indicated by 323, a plurality of profiles are detected, an optimum profile is selected from the profiles, and an actual information recording operation is performed under conditions corresponding to the selected profile.

[0194] Further, the controller 90 sets the profile based on the detected profile or the selected profile.
An output level corresponding to a desired diffraction efficiency or a time from the start of recording at which the output level is obtained is obtained. The controller 90 monitors the output level of the CCD array 133 at the time of actual information recording, and stops recording when the output level reaches an output level corresponding to a desired diffraction efficiency obtained in advance. Alternatively, the controller 90
In actual recording of information, the recording is stopped when the elapsed time after the start of the recording reaches the time from the start of recording at which an output level corresponding to a desired diffraction efficiency obtained in advance is obtained. With such an operation, it is possible to form a recording pattern with a desired diffraction efficiency on the optical information recording medium 1.

As described above, in the present embodiment,
The recorded information can be collated using the DRAW function. FIG. 64 shows a circuit configuration necessary for performing this collation in the optical information recording / reproducing apparatus according to the present embodiment. As shown in this figure, the optical information recording / reproducing apparatus is provided with information to be recorded by the controller 90, and the information is transmitted to the spatial light modulator (S in FIG. 64).
LM. ) An encoder 331 that encodes the data into a modulation pattern of 125;
3 from the controller 90 to the encoder 3
A decoder 322 that decodes the data to be in the form given to the controller 31;
A comparison unit 333 that compares the data supplied to the decoder 31 with the data obtained by the decoder 322 and sends information of the comparison result to the controller 90. Comparison section 333
Sends, for example, information on the degree of coincidence of two pieces of data to be compared or information on an error rate (error rate) to the controller 90 as information on the comparison result. For example, when the information of the comparison result sent from the comparison unit 333 is within a range in which a data error can be repaired,
The recording operation is continued, and if the information of the comparison result is out of the range where the data error can be repaired, the recording operation is stopped.

As described above, since the optical information recording / reproducing apparatus according to the present embodiment has the DRAW function, the sensitivity unevenness of the optical information recording medium 1, the change in external environmental temperature, Even if there is disturbance such as fluctuation of the output of the light source device 112, the recording operation can be performed in an optimal recording state.

Further, according to the present embodiment, since the function of collating the recorded information with the recording of the information is provided, high-speed recording can be performed while maintaining high reliability. This function is particularly useful when recording information at a high transfer rate. Reproduction of information in a state where the information is not fixed has the same effect as performing overwriting, and deteriorates the quality of recorded information. In the verification function of the embodiment, since the confirmation of the recorded information is completed during the recording operation, no problem occurs.

Next, the WPC function at the time of multiplex recording will be described. When a plurality of pieces of information are multiplex-recorded on the same portion of the optical information recording medium 1 by changing the modulation pattern of the recording reference light, the diffraction efficiency of the previously recorded recording pattern gradually increases due to the subsequent recording. descend. The WPC function in the present embodiment is a function of controlling the recording reference light and the information light at the time of recording so that substantially the same diffraction efficiency is obtained for each recording pattern for each information to be multiplex-recorded at the time of multiplex recording. is there.

Here, the diffraction efficiency of the recording pattern includes the intensity of the recording reference light and the information light, the irradiation time of the recording reference light and the information light, the intensity ratio between the recording reference light and the information light, and the intensity of the recording reference light. It depends on parameters such as the modulation pattern and the number of times of recording in the same place of the optical information recording medium 1 and the number of times of recording. Therefore, in the WPC function, at least one of these parameters may be controlled. In order to easily perform the control, the intensity and the irradiation time of the recording reference light and the information light may be controlled. When controlling the intensity of the recording reference light and the information light, the intensity is reduced as the recording is performed later. When controlling the irradiation time of the recording reference light and the information light, the irradiation time is reduced as the recording is performed later.

In the WPC function according to the present embodiment, the CCD array 1 shown in FIG.
1 to m based on 33 output level profiles
(M is an integer of 2 or more) controls the recording reference light and the information light at the time of the third recording. FIG. 63 shows an example of the irradiation time when the irradiation time of the recording reference light and the information light is controlled. That is, in the example shown in FIG. 63, it is assumed that recording is performed five times in the same location of the optical information recording medium 1, and T ₁ , T ₂ , T ₃ , T ₄ , and T ₅ are respectively
At the time of the first recording, at the time of the second recording, at the time of the third recording,
At the time of the fifth recording, the irradiation time of the recording reference light and the information light at the time of the fifth recording is shown.

As described above, according to the present embodiment, it is possible to make the diffraction efficiencies of the recording patterns for each multiplex-recorded information substantially equal.

According to the optical information recording / reproducing apparatus according to the present embodiment, a large amount of information can be recorded on the optical information recording medium 1 at high density. This means that if a defect or the like occurs in the optical information recording medium 1 after the information is recorded and some of the information cannot be reproduced, the amount of information lost due to the defect increases. In the present embodiment, in order to prevent such information loss and improve reliability, as described below, a RAID (Redundant Arra
ys of Inexpensive Disks) technology can be used to record information.

The RAID technology is a technology for improving the reliability of recording by recording data with redundancy using a plurality of hard disk devices. RA
The IDs are classified into five from RAID-1 to RAID-5. In the following description, a typical R
A description will be given taking AID-1, RAID-3 and RAID-5 as examples. RAID-1 is a method of writing the same contents to two hard disk drives, and is also called mirroring. RAID-3 is a method in which input data is divided into a fixed length and recorded on a plurality of hard disk devices, and parity data is generated and written into another hard disk device. In RAID-5, a data division unit (block) is increased, one divided data is recorded as a data block in one hard disk drive, and parity data for a data block corresponding to each other in each hard disk drive is converted into a parity block. Is recorded in another hard disk drive, and the parity blocks are distributed to all hard disk drives.

Information recording method to which the RAID technology is applied in the present embodiment (hereinafter, referred to as distributed recording method).
Is for recording information by replacing the hard disk device in the above description of RAID with an interference area 313 in the optical information recording medium 1.

FIG. 65 is an explanatory diagram showing an example of the distributed recording method according to the present embodiment. In this example, information to be recorded on the optical information recording medium 1 is a series of data DATA.
, And the same data DATA1, DATA2, DATA3,... Are transmitted to the plurality of interference areas 313a to 313 in the optical information recording medium 1.
3e. In addition, each interference area 313a-31
In 3e, a plurality of data are multiplex-recorded by phase coding multiplexing. This recording method is RAID-1
It corresponds to. According to this recording method, even if data cannot be reproduced in any of the plurality of interference areas 313a to 313e, data can be reproduced from other interference areas.

FIG. 66 is an explanatory diagram showing another example of the distributed recording method according to the present embodiment. In this example, information to be recorded on the optical information recording medium 1 is a series of data DATA.
1, DATA2, DATA3,..., DATA12. This data is divided into a plurality of interference areas 31.
3a to 313d and a plurality of interference areas 31
3a to 313d, and generates parity data for the data to be recorded in the interference area 313e.
It is recorded in. More specifically, in this recording method, the data DATA1 to DATA4 are recorded in the interference areas 313a to 313d, respectively, and the data DATA1 to DATA4 are recorded.
Parity data PARITY for 1 to DATA4
(1-4) is recorded in the interference area 313e, and the data DA
TA5 to DATA8 are the interference areas 313a to 313, respectively.
13d, the parity data PARITY (5-8) for the data DATA5 to DATA8 is recorded in the interference area 313e, and the data DATA9 to DATA12 is recorded.
Are recorded in the interference areas 313a to 313d, respectively.
Parity data PARITY (9-12) for the data DATA9 to DATA12 is recorded in the interference area 313e. In each of the interference regions 313a to 313e, a plurality of data are multiplex-recorded by phase coding multiplexing. This recording method corresponds to RAID-3. According to this recording method, the plurality of interference areas 31
Even if data cannot be reproduced in any of 3a to 313d, the data can be restored using the parity data recorded in the interference area 313e.

FIG. 67 is an explanatory diagram showing still another example of the distributed recording method according to the present embodiment. In this example, information to be recorded on the optical information recording medium 1 is a series of data DA.
TA1, DATA2, DATA3,..., DATA12, this data is divided and recorded in four of the plurality of interference areas 313a to 313e, and parity data for the recorded data is generated. This parity data is transferred to a plurality of interference areas 313a.
313e in the remaining interference area. In this method, an interference area for recording parity data is sequentially changed. More specifically, in this recording method, the data DATA1 to DATA4 are recorded in the interference areas 313a to 313d, respectively, and the data D1 to DATA4 are recorded.
Parity data PARI for ATA1 to DATA4
TY (1-4) is recorded in the interference area 313e, and the data DATA5 to DATA8 are respectively stored in the interference area 313a.
313c and 313e, and the data DATA5
Parity data PARITY (5-
8) is recorded in the interference area 313d, and the data DATA9
To DATA12 are the interference regions 313a and 313, respectively.
b, 313d and 313e, and the data DATA9
~ PARITY DATA PARITY for DATA12
(9-12) is recorded in the interference area 313c. In addition,
In each of the interference regions 313a to 313e, a plurality of data are multiplex-recorded by phase encoding multiplexing. This recording method corresponds to RAID-5. According to this recording method, even if the data cannot be reproduced in any of the plurality of interference areas where the data is recorded, the data can be restored using the parity data.

For example, the distributed recording method as shown in FIGS. 65 to 67 is performed under the control of a controller 90 as control means.

FIG. 68 shows an example of the arrangement of a plurality of interference areas used in the above-described distributed recording method. In this example, the interference areas used in the distributed recording method are a plurality of adjacent interference areas 313 in one track. In this case, it is preferable that the plurality of interference areas 313 used in the distributed recording method be interference areas within an accessible range within the visual field. This is because each interference area 313 can be accessed at high speed.

FIG. 69 shows another example of the arrangement of a plurality of interference areas used in the above-described distributed recording method.
In this example, the plurality of interference regions used in the distributed recording method are divided into a plurality of interference regions 313 two-dimensionally adjacent in the radial direction 331 and the track direction 332 of the optical information recording medium 1.
And In this case, among the plurality of interference regions used in the distributed recording method, it is preferable that the plurality of interference regions 313 adjacent in the track direction 332 be within an accessible range within the visual field. It is track direction 3
This is because each interference area 313 adjacent to 32 can be accessed at high speed.

In the distributed recording method according to the present embodiment, a series of data is stored in a plurality of adjacent interference areas 313.
A plurality of interfering regions 31 that are not recorded in
3 may be recorded separately.

Up to this point, the distributed recording method in the case where a plurality of data are multiplex-recorded in one interference area 313 by phase encoding multiplexing has been described. Also, a distributed recording method can be realized. As an example,
Referring to FIG. 70, shift multiplexing (shift
A description will be given of a distributed recording method when a plurality of data are multiplex-recorded using a method called "multiplexing".
The shift multiplexing means that a plurality of interference areas 313 are provided on the optical information recording medium 1 as shown in FIG.
Are formed so that they are slightly shifted from each other in the horizontal direction and partly overlap each other, and a plurality of pieces of information are multiplex-recorded. Although FIG. 70 shows an example in which the plurality of interference regions 313 used in the distributed recording method are two-dimensionally arranged, the plurality of interference regions 313 used in the distributed recording method are shown.
May be arranged adjacent to each other in the same track.
In FIG. 70, the arrow indicated by reference numeral 334 indicates the order of recording. In the distributed recording method using multiplexing, data divided from a series of data and parity data are dispersedly recorded in a plurality of interference areas 313.

Further, even when a plurality of data are multiplex-recorded by using both phase encoding multiplexing and shift multiplexing, the distributed recording method can be realized. FIG. 71 shows that, in the track direction 332 of the information recording medium 1, interference areas 313 for multiplexing and recording information by phase encoding multiplexing are formed without overlapping each other, and in the radial direction 331 of the information recording medium 1, shift multiplication is performed. An example is shown in which adjacent interference regions 313 are formed so as to be slightly shifted from each other in the horizontal direction and partially overlap each other by using mixing. Each of the interference regions 313 in this example is the interference region 313a in FIG. 65 to FIG.
313e.

Next, referring to FIGS. 72 and 73, as an application example of the optical information recording / reproducing apparatus according to the present embodiment,
A juke apparatus using the optical information recording / reproducing apparatus according to the present embodiment will be described. In addition, the juke device is
This is a large-capacity information recording / reproducing apparatus having an autochanger mechanism for exchanging recording media.

FIG. 72 is a perspective view showing the appearance of the juke device, and FIG. 73 is a block diagram showing the circuit configuration of the juke device. This juke device has a front panel block 401 provided on the entire surface side of the juke device, and a robotics block 402 constituting the inside of the juke device.
A rear panel block 403 provided on the back side of the juke device; a first disk array 404 provided inside the juke device and connected to a plurality of optical information recording / reproducing devices; A second disk array 405 to which a playback device is connected, and a power supply block 40 for supplying predetermined power to each part of the juke device
6 is provided.

The front panel block 401 includes a front door 407 that is opened and closed when the disk arrays 404 and 405 are replaced, and a front panel 408.

A front panel 408 has a keypad 409 having various operation keys, a display 410 for displaying, for example, an operation mode and the like, and a front door 40.
Functional switch 4 for specifying opening and closing of 7
11, a mail slot 412 which is an insertion / ejection port for the optical information recording medium 1, and an optical information recording medium for transferring and ejecting the inserted optical information recording medium 1 to a mailbox (not shown) via the mail slot 412. There are provided a transfer motor 413 for transferring 1 from a mail box to a mail slot 412, and a full sensor 414 for detecting that the number of the optical information recording media 1 inserted in the juke apparatus has reached a specified number.

The front door 407 has a front door 4
07, a door sensor 415 for detecting the open / close state of the door, a door lock solenoid 416 for controlling the opening / closing of the front door 407, and an interlock switch 417 for controlling the opening / closing of the front door 407 in response to the operation of the functional switch 411. ing.

The robotics block 402 is provided in a lower magazine 421 in which, for example, ten optical information recording media 1 can be stored, and is provided so as to be laminated on the upper surface of the lower magazine 421. Has an upper magazine 422 capable of storing, for example, ten optical information recording media 1, and a controller block 423 for controlling the entire juke apparatus.

The robotics block 402 includes a gripping motor 424 for controlling a gripping operation of a manipulator (not shown) for moving the optical information recording medium 1 inserted in the juke device to a predetermined position, and a controller block 423. And the rotation number and rotation direction of the grip operation motor 424, which controls the rotation number and rotation direction of the grip operation motor 424, and the rotation number and rotation direction of the grip operation motor 424. And a gripping operation encoder 426 to be supplied. Further, the robotics block 402 includes a rotation operation motor 427 for controlling the rotation of the manipulator in a clockwise direction, a counterclockwise direction, or a left and right direction, and the rotation speed of the rotation operation motor 427 according to the control of the controller block 423. A rotation operation motor controller 428 that controls the rotation direction and a rotation operation encoder 429 that detects the number of rotations and the rotation direction of the rotation operation motor 427 and supplies the detection data to the controller block 423 are provided. Also, the robotics block 402
An up / down operation motor 430 for controlling movement of the manipulator in the up / down direction, and an up / down operation motor controller 431 for controlling the number of rotations and the rotation direction of the up / down operation motor 430 according to the control of the controller block 423.
And the number of rotations and the direction of rotation of the up / down operation motor 430,
And an up / down operation encoder 432 for supplying to the

Further, the robotics block 402 includes a transfer motor controller 433 for controlling the number of rotations and the direction of rotation of the transfer motor 413 for inserting and ejecting the optical information recording medium 1 through the mail slot 412.
And a clear path sensor 434 and a clear path emitter 420.

The rear panel block 403 is a connector terminal 4 for RS232C, which is an input / output terminal for serial transmission.
35, a UPS (Uninterruptible Power System) connector terminal 436, and a first SCSI (Small Computer System Interface) which is an input / output terminal for parallel transmission.
) Connector terminal 437 and a second SCSI connector terminal 438 which is also an input / output terminal for parallel transmission.
And an AC (AC) power supply connector terminal 439 connected to a commercial power supply.

[0224] The RS232C connector terminal 435 and the UPS connector terminal 436 are connected to the controller block 423, respectively. The controller block 423 converts serial data supplied via the RS232C connector terminal 435 into parallel data and supplies the parallel data to each of the disk arrays 404 and 405.
The parallel data from each of the disk arrays 404 and 405 is converted into serial data and supplied to the RS232C connector terminal 435.

Each SCSI connector terminal 437,
438 is connected to the controller block 423 and each of the disk arrays 404 and 405. Each of the disk arrays 404 and 405 has a SCSI connector terminal 4
37, 438, the controller block 423 sends the data directly to each disk array 404,
405 is converted into serial data and supplied to the RS232C connector terminal 435.

The AC power connector terminal 439 is connected to the power supply block 406. The power supply block 406 outputs +5 V, +12 V, and +5 V based on the commercial power supplied through the AC power connector terminal 439.
Each power of + 24V and -24V is formed and supplied to other blocks.

A manipulator (not shown) includes a carriage having grippers for performing operations such as picking up the optical information recording media 1 transferred to the mailbox via the mail slot 412 one by one, and a carriage holding unit for holding the carriage. And a drive unit for controlling the carriage up and down, left and right, front and back, and rotation. Inside the juke device, a substantially rectangular shape is formed on the bottom part,
From the four corners of the rectangular shape to the upper surface of the juke device, four columns are provided so as to be perpendicular to the bottom surface. The carriage holding portion holds the carriage in a lateral, front and rear, and rotatable manner, and has, at both ends thereof, a column holding portion for holding the column so that the carriage holding portion can move up and down along four columns. ing.

The carriage driving section generates a driving force for controlling the movement of such a manipulator up and down along the column, generates a driving force for controlling the carriage left and right, front and rear, and rotation, and uses a gripper. A driving force for grasping the optical information recording medium 1 is generated.

[0229] As shown in FIG.
7 is supported at one end by a hinge 450 so as to be openable and closable, and by opening and closing the front door 407, the lower magazine 421, the upper magazine 422, and the first and second disk arrays 404 and 405 are pulled out or respectively. It can be installed. Each magazine 421,
Reference numeral 422 denotes a box shape in which the ten optical information recording media 1 accommodated in the cartridges are accommodated in a form stacked in parallel with the bottom surface of the juke device. The magazines 421 and 422 are inserted from the rear side (the surface facing the front side where the front door 407 is provided when the magazines 421 and 422 are mounted on the juke apparatus).
The user mounts the optical information recording medium 1 on each magazine 4.
21 and 422 can be taken out and stored manually, and the magazines 421 and 422 storing the optical information recording medium 1 can be mounted at once by mounting the magazines 421 and 422 in a juke apparatus. Further, by inserting the optical information recording medium 1 through the mail slot 412, the inserted optical information recording medium 1 is transferred to a mailbox, and the optical information recording medium 1 transferred to the mailbox is used by the manipulator. The magazines 421 and 422 are mounted. Thus, the optical information recording medium 1 can be automatically mounted on each of the magazines 421 and 422.

The first and second disk arrays 404,
Reference numeral 405 includes a RAID controller and a drive array in which first to fifth optical information recording / reproducing devices are connected.

Each optical information recording / reproducing apparatus has a disk insertion / ejection port, and the optical information recording medium 1 is inserted into each optical information recording / reproduction apparatus or each optical information recording / reproduction via this disk insertion / ejection port. It is discharged from the device. The RAID controller is connected to the controller block 423. Under the control of the controller block 423, each optical information recording / reproducing apparatus is controlled in accordance with a RAID1, RAID3, or RAID5 recording method. In addition, RAID1,
Each of the recording methods RAID3 and RAID5 is selected by a key operation of a keypad 409 provided on the front panel 408.

In this juke apparatus, the disk array 4
Data recording is performed by using a RAID1, RAID3, or RAID5 recording method by using the recording methods 04, 405. In order to record data in this manner, it is necessary to mount the optical information recording medium 1 in the juke apparatus in advance. Optical information recording medium 1 for juke device
There are the following two mounting methods.

In the first mounting method, as shown in FIG. 72, the front door 407 is opened, the lower magazine 421 and the upper magazine 422 are taken out, and optical information recording is manually performed on these magazines 421 and 422. This is a method for mounting the medium 1.

The second mounting method is a method of mounting the optical information recording media 1 one by one via the mail slot 412 shown in FIG. When the optical information recording medium 1 is mounted in the mail slot 412, the controller block 423
Detects this, drives and controls the transfer motor 413,
The optical information recording medium 1 is transferred to a mailbox. When the optical information recording medium 1 is transferred to the mailbox, the controller block 423 controls the drive of the up / down operation motor 430 to control the movement of the manipulator in the direction in which the mailbox is provided, and the grip operation. The drive of the motor 424 is controlled to move the optical information recording medium 1 picked up by the gripper provided on the manipulator to the empty disk storage section of the magazines 421, 422. And the gripping motor 4
The drive of the optical information recording medium 1 is controlled to release the optical information recording medium 1 picked up by the gripper in the disk storage section. The controller block 423 controls each unit so as to repeat such a series of mounting operations every time the optical information recording medium 1 is inserted through the mail slot 412.

As described above, when the optical information recording medium 1 is mounted on each of the magazines 421 and 422 by the first mounting method or the second mounting method, the controller block 423 is set.
Controls the manipulator to transfer the optical information recording medium 1 stored in the lower magazine 421 or the upper magazine 422 to the first disk array 404 or the second disk array 405. Each disk array 404,
Each of the magazines 405 is capable of mounting five optical information recording media 1, and each of the magazines 42 is operated by a manipulator.
Out of the total of 20 optical information recording media 1 accommodated in 1,422, five are mounted on the first disk array 404, and the other five are mounted on the second disk array 405.

When recording the data, the user
By operating the keypad 409, RAID1,
A desired recording method is selected from the RAID3 or RAID5 recording methods, and the keypad 409 is operated to designate the start of data recording. Disk arrays 404, 40
5 has an RS232C connector terminal 435 or a
1. Data to be recorded is supplied via the second SCSI connector terminals 437 and 438. The controller block 423 operates via a RAID controller provided in each of the disk arrays 404 and 405 so that when data recording start is specified, data recording is performed in accordance with the selected recording method. The respective disk arrays 404 and 405 are controlled.

In this juke apparatus, the hard disk drive in RAID using the conventional hard disk drive is replaced with five optical information recording / reproducing devices provided in each of the disk arrays 404 and 405, and the RAID system uses RAID.
Data is recorded in accordance with a recording method selected from among 1, 3, and 5 recording methods. In this juke apparatus, the data interface is not limited to the interface described in the above description.

By the way, in the optical information recording / reproducing apparatus according to the present embodiment, copy protection and confidentiality can be easily realized as in the first embodiment. Further, an optical information recording medium 1 on which various types of information (for example, various kinds of software) having different reference light modulation patterns are recorded is provided to a user, and each type of information can be reproduced at the request of the user. It is possible to realize an information distribution service in which information of light modulation patterns is individually provided as key information for a fee.

Further, the modulation pattern of the phase of the reference light serving as key information for extracting predetermined information from the optical information recording medium 1 may be created based on information unique to an individual who is a user. Information unique to an individual includes a password, a fingerprint, a voiceprint, and an iris pattern.

FIG. 74 shows a main part of the optical information recording / reproducing apparatus according to the present embodiment in the case where the modulation pattern of the phase of the reference light is created based on the information unique to the individual as described above. There is an example of a configuration. In this example, the optical information recording / reproducing apparatus includes a personal information input unit 501 for inputting personal information such as a fingerprint and the like, and modulates the phase of the reference light based on the information input from the personal information input unit 501. When a pattern is created and information is recorded or reproduced, information on the created modulation pattern is given to the phase spatial
17, a phase modulation pattern encoder 502 that drives
A card 504 in which information of the modulation pattern created by the phase modulation pattern encoder 502 is recorded, and when the card 504 is mounted, the information of the modulation pattern recorded in the card 504 is converted to the phase modulation pattern. Issue card to send to encoder 502
An input unit 503 is provided.

In the example shown in FIG. 74, when the user records information on the optical information recording medium 1 using the optical information recording / reproducing apparatus according to the present embodiment, When the personal information such as a fingerprint or the like is input, the phase modulation pattern encoder 502 causes the personal information input unit 50 to input the information.
A modulation pattern of the phase of the reference light is created on the basis of the information input from
17 with the information of the created modulation pattern,
The phase spatial modulator 117 is driven. Thereby, the information is recorded on the optical information recording medium 1 in association with the modulation pattern of the phase of the reference light created based on the unique information of the individual who is the user. Also, the phase modulation pattern encoder 502 sends information of the created modulation pattern to the card issuing / inputting unit 503, and the card issuing / inputting unit 503.
Issues a card 504 in which information of the received modulation pattern is recorded.

In order for the user to reproduce the information recorded as described above from the optical information recording medium 1, as in the case of recording, it is necessary to input personal unique information to the personal information input section 501. , The card 504 to the card issuing / input unit 503
Attach to

When personal information specific to an individual is input to personal information input section 501, phase modulation pattern encoder 502 modulates the phase of the reference light based on the information input from personal information input section 501. When a pattern is created and information is reproduced, the information of the created modulation pattern is given to the phase spatial modulator 117, and the phase spatial modulator 117
Drive. At this time, if the modulation pattern of the phase of light at the time of recording matches the modulation pattern of the phase of the reference light at the time of reproduction, desired information is reproduced. Note that even if the same individual unique information is input to the personal information input unit 501, the phase modulation pattern encoder 502 prevents the creation of different modulation patterns at the time of recording and at the time of reproduction. Even if the information input from the information input unit 501 differs to some extent, the same modulation pattern may be created in the phase modulation pattern encoder 502.

On the other hand, when the card 504 is attached to the card issue / input section 503, the card issue / input section 503
Sends the information of the modulation pattern recorded on the card 504 to the phase modulation pattern encoder 502, and the phase modulation pattern encoder 502 gives the transmitted information of the modulation pattern to the phase spatial modulator 117, The modulator 117 is driven. Thereby, desired information is reproduced.

Other configurations, operations, and effects of the present embodiment are the same as those of the first embodiment.

The present invention is not limited to the above embodiments. For example, in the above embodiments, address information and the like are recorded in advance in the address servo area 6 of the optical information recording medium 1 by emboss pits. However, a portion of the hologram layer 3 close to the protective layer 4 is selectively irradiated with high-power laser light in the address servo area 6 without providing emboss pits in advance. Formatting may be performed by recording address information or the like by selectively changing the rate.

The element for detecting information recorded on the hologram layer 3 is not a CCD array but a MOS
Optical sensor in which a solid-state image sensor and a signal processing circuit are integrated on a single chip (for example, refer to the document “O plus
E, September 1996, No. 202, pages 93-99 ". ) May be used. Since this smart optical sensor has a high transfer rate and a high-speed calculation function, high-speed reproduction can be performed by using this smart optical sensor. For example, reproduction can be performed at a transfer rate on the order of G bits / sec. Becomes possible.

In particular, when a smart optical sensor is used as an element for detecting information recorded on the hologram layer 3, address information and the like are written in the address servo area 6 of the optical information recording medium 1 by emboss pits. Instead of recording, address information and the like of a predetermined pattern are recorded in advance in the same manner as the recording using holography in the data area 7, and the pickup is set to the same state as during reproduction during servo operation. You may make it detect address information etc. with a smart optical sensor. In this case, the basic clock and the address can be obtained directly from the detection data of the smart optical sensor. The tracking error signal can be obtained from information on the position of the reproduction pattern on the smart optical sensor. The focus servo can be performed by driving the objective lens 12 so that the contrast of the reproduction pattern on the smart optical sensor is maximized. Also, at the time of reproduction, it is possible to perform focus servo by driving the objective lens so that the contrast of the reproduction pattern on the smart optical sensor is maximized.

In each embodiment, the information on the modulation pattern and the wavelength of the reference light may be provided to the controller 90 from an external host device.

[0250]

As described above, according to the optical information recording apparatus according to any one of claims 1 to 5, or the optical information recording method according to claim 6, the information light carrying information and the phase are spatially different. The information recording layer is irradiated from the same side with the recording-referenced light that has been spatially modulated, so that information can be multiplex-recorded by phase encoding multiplexing, and the optical system for recording can be reduced. The effect that it can comprise is produced.

According to the optical information recording apparatus of the present invention, the positions of the information light and the recording reference light with respect to the optical information recording medium are controlled by using the information recorded in the positioning area of the optical information recording medium. Therefore, there is an effect that positioning of light for recording can be accurately performed.

Further, according to the optical information recording apparatus of the third aspect, the recording optical system is arranged so that the optical axis of the information light and the optical axis of the recording reference light are arranged on the same line. Since the illumination light is irradiated with the reference light, the optical system for recording can be further reduced in size.

According to the optical information recording apparatus of the fourth aspect, the information light generating means generates information light in a plurality of wavelength ranges, and the recording reference light generating means generates the information light in the same plurality of wavelengths as the information light. Since the recording reference light for the area is generated, an effect is obtained that more information can be multiplex-recorded.

According to the optical information recording apparatus of the present invention, the information light generating means and the recording reference light generating means are controlled to record information on the optical information recording medium so as to have redundancy. Since the control means is provided, there is an effect that the reliability can be further improved.

According to the optical information reproducing apparatus of the present invention or the optical information reproducing method of the present invention, the reproducing reference light whose phase is spatially modulated is transmitted to the information recording layer. The reproduction light generated from the information recording layer by being irradiated with the reproduction reference light is collected from the same side as the side on which the information recording layer is irradiated with the reproduction reference light. Since the collected reproduction light is detected, it is possible to reproduce the information multiplexed and recorded by the phase encoding multiplexing, and to make the optical system for reproduction small.

According to the optical information reproducing apparatus of the eighth aspect, the position of the reproduction reference light with respect to the optical information recording medium is controlled using the information recorded in the positioning area of the optical information recording medium. Therefore, there is an effect that positioning of light for reproduction can be performed with high accuracy.

Further, according to the optical information reproducing apparatus of the ninth aspect, the reproducing optical system is arranged such that the optical axis of the reproducing reference light and the optical axis of the reproducing light are arranged on the same line. Is performed and the reproduction light is collected, so that an effect that the optical system for reproduction can be further reduced can be obtained.

Further, according to the optical information reproducing apparatus of the tenth aspect, the reproducing reference light generating means generates the reproducing reference light in a plurality of wavelength ranges, and the detecting means generates the same plural reference light as the reproducing reference light. Is detected, the information recorded by the recording reference light and the information light in a plurality of wavelength ranges can be reproduced.

According to the optical information recording apparatus of the present invention or the optical information recording method of the present invention, an information beam having a selected wavelength and carrying information can be selected. A recording reference light having the wavelength
Since the information recording layer is irradiated from the same surface side, there is an effect that information can be multiplex-recorded by wavelength multiplexing and an optical system for recording can be made small.

According to the optical information recording device of the present invention, the positions of the information light and the recording reference light with respect to the optical information recording medium are controlled using the information recorded in the positioning area of the optical information recording medium. Therefore, there is an effect that positioning of light for recording can be accurately performed.

[0261] According to the optical information recording apparatus of the present invention, the recording optical system is arranged so that the optical axis of the information light and the optical axis of the recording reference light are arranged on the same line. Since the illumination light is irradiated with the reference light, the optical system for recording can be further reduced in size.

According to the optical information reproducing apparatus of the present invention or the optical information reproducing method of the present invention, the reproducing reference light having the selected wavelength is applied to the information recording layer. The reproduction light generated from the information recording layer by irradiating the reproduction reference light is collected from the same side as the side on which the information recording layer is irradiated with the reproduction reference light, and collected. Since the reproduced light is detected, the information multiplexed and recorded by wavelength multiplexing can be reproduced, and the optical system for reproduction can be made smaller.

According to the optical information reproducing apparatus of the present invention, the position of the reproduction reference light with respect to the optical information recording medium is controlled by using the information recorded in the positioning area of the optical information recording medium. Therefore, there is an effect that positioning of light for reproduction can be performed with high accuracy.

According to the optical information reproducing apparatus of the eighteenth aspect, the reproducing optical system is arranged such that the optical axis of the reproducing reference light and the optical axis of the reproducing light are arranged on the same line. Is performed and the reproduction light is collected, so that an effect that the optical system for reproduction can be further reduced can be obtained.

According to the optical information recording device of the present invention or the optical information recording method of the present invention, an information light having a selected wavelength and carrying information can be selected. The information recording layer is irradiated with the recording reference light having the wavelength that has been set and the phase is spatially modulated, from the same surface side. This has the effect of enabling multiplex recording and making the optical system for recording smaller.

According to the optical information recording apparatus of the present invention, the positions of the information light and the recording reference light with respect to the optical information recording medium are controlled using the information recorded in the positioning area of the optical information recording medium. Therefore, there is an effect that positioning of light for recording can be accurately performed.

Further, according to the optical information recording apparatus of the present invention, the recording optical system is arranged such that the optical axis of the information light and the optical axis of the reference light for recording are arranged on the same line. Since the illumination light is irradiated with the reference light, the optical system for recording can be further reduced in size.

According to the optical information reproducing apparatus or the optical information reproducing method according to any one of claims 24 to 26, the optical information reproducing apparatus has the selected wavelength and the phase is spatially modulated. The information recording layer is irradiated with the reproduced reference light, and the reproduction light generated from the information recording layer by irradiating the information reference layer is irradiated with the reproduction reference light. Collected from the same side as the side, and the collected reproduced light is detected, so that information multiplexed and recorded by wavelength multiplexing and phase encoding multiplexing can be reproduced, and the optical system for reproduction is reduced in size. The effect that it can comprise is produced.

According to the optical information reproducing apparatus of claim 25, the position of the reproducing reference light with respect to the optical information recording medium is controlled using the information recorded in the positioning area of the optical information recording medium. Therefore, there is an effect that positioning of light for reproduction can be performed with high accuracy.

[0270] According to the optical information reproducing apparatus of the twenty-sixth aspect, the reproducing optical system is configured such that the optical axis of the reproducing reference light and the optical axis of the reproducing light are arranged on the same line. Is performed and the reproduction light is collected, so that an effect that the optical system for reproduction can be further reduced can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a pickup and an optical information recording medium in an optical information recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an overall configuration of the optical information recording / reproducing apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a detection circuit in FIG. 2;

FIG. 4 is an explanatory diagram showing a state of the pickup shown in FIG. 1 during servo.

FIG. 5 is an explanatory diagram for explaining polarized light used in the first embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating a state of the pickup illustrated in FIG. 1 during recording.

FIG. 7 is an explanatory diagram showing a state of light in the pickup in the state shown in FIG. 6;

FIG. 8 is an explanatory diagram showing a state of light in the pickup in the state shown in FIG. 6;

FIG. 9 is an explanatory diagram showing a state of the pickup shown in FIG. 1 during reproduction.

FIG. 10 is an explanatory diagram showing a state of light in the pickup in the state shown in FIG. 9;

FIG. 11 is an explanatory diagram showing a state of light in the pickup in the state shown in FIG. 9;

FIG. 12 is an explanatory diagram for describing a method of recognizing a reference position in a reproduction light pattern from detection data of the CCD array in FIG. 1;

13 is an explanatory diagram for describing a method of recognizing a reference position in a reproduction light pattern from detection data of the CCD array in FIG. 1. FIG.

FIG. 14 is an explanatory diagram showing a pattern of information light and a pattern of reproduction light in the pickup shown in FIG. 1;

FIG. 15 is an explanatory diagram showing the contents of data determined from the pattern of the reproduction light detected by the pickup shown in FIG. 1 and an ECC table corresponding to the data.

FIG. 16 is a characteristic diagram showing a state in which light absorptivity decreases at a plurality of wavelength positions due to irradiation of light of a plurality of wavelengths in a light absorption spectrum of a hole burning material.

FIG. 17 is an explanatory diagram illustrating a configuration of a pickup according to a third embodiment of the present invention.

FIG. 18 is a plan view showing a configuration of an optical unit including each element constituting a pickup according to a third embodiment of the present invention.

19 is an explanatory diagram illustrating an example of the optical element for optical rotation in FIG. 17;

FIG. 20 is an explanatory diagram showing a configuration of a pickup capable of using laser beams of three colors in the third embodiment of the present invention.

FIG. 21 is a plan view showing a slide feed mechanism of the optical unit shown in FIG.

22 is a partially cutaway side view showing the slide feed mechanism shown in FIG. 21 in a stationary state.

FIG. 23 when the optical unit is slightly displaced;
5 is a partially cutaway side view showing the slide feed mechanism shown in FIG.

FIG. 24 is an explanatory diagram showing the operation of the actuator shown in FIG. 21.

FIG. 25 is an explanatory diagram showing a moving direction of the objective lens by seeking in the pickup shown in FIG. 17 and a direction of access in the visual field.

FIG. 26 is an explanatory diagram for describing positioning of reference light and information light according to the third embodiment of the present invention.

FIG. 27 is an explanatory diagram showing an example of a locus of the center of an objective lens when a plurality of locations on an optical information recording medium are accessed by using both movement by seek and access within a visual field in a third embodiment of the present invention. is there.

FIG. 28 is a plan view showing a cartridge for storing an optical information recording medium according to the third embodiment of the present invention.

FIG. 29 is a plan view of the cartridge shown in FIG. 28 with a shutter opened.

FIG. 30 is a plan view showing an example in which two optical units are arranged so as to face one surface of an optical information recording medium according to the third embodiment of the present invention.

FIG. 31 is a plan view showing an example in which four optical units are provided in the third embodiment of the present invention.

FIG. 32 is a sectional view taken along line AA ′ of FIG. 31.

FIG. 33 is a sectional view taken along line BB ′ of FIG. 31;

FIG. 34 is a plan view showing an example in which 16 optical units are provided in the third embodiment of the present invention.

FIG. 35 is a half sectional view of an air gap type optical information recording medium according to a third embodiment of the present invention.

FIG. 36 is an exploded perspective view of a half of an air gap type optical information recording medium according to a third embodiment of the present invention.

FIG. 37 is a half perspective view of an air gap type optical information recording medium according to a third embodiment of the present invention.

FIG. 38 is a half sectional view of a transparent substrate gap type optical information recording medium according to a third embodiment of the present invention.

FIG. 39 is an exploded perspective view of a half of an optical information recording medium of a transparent substrate gap type according to a third embodiment of the present invention.

FIG. 40 is a perspective view of a half of an optical information recording medium of a transparent substrate gap type according to a third embodiment of the present invention.

FIG. 41 is a sectional view of a single-sided optical information recording medium having a thickness of 1.2 mm according to a third embodiment of the present invention.

FIG. 42 is a sectional view of a single-sided optical information recording medium having a thickness of 0.6 mm according to the third embodiment of the present invention.

43 is an explanatory diagram showing how to irradiate the single-sided optical information recording medium shown in FIG. 41 or 42 with the recording reference light and the information light.

FIG. 44 is a cross-sectional view of a double-sided optical information recording medium of a transparent substrate gap type according to a third embodiment of the present invention.

FIG. 45 is a sectional view of a double-sided air gap type optical information recording medium according to a third embodiment of the present invention.

FIG. 46 is an explanatory diagram showing a method of irradiating the recording reference light and the information light to the double-sided optical information recording medium shown in FIG. 44 or FIG.

FIG. 47 is an explanatory diagram showing a single-sided optical disk.

48 is an explanatory diagram showing a case where the optical disc shown in FIG. 47 is used in the optical information recording / reproducing device according to the third embodiment of the present invention.

FIG. 49 is an explanatory diagram showing a double-sided optical disk.

FIG. 50 is an explanatory diagram showing a case where the optical information recording / reproducing apparatus according to the third embodiment of the present invention uses the optical disk shown in FIG. 49.

FIG. 51 is a perspective view showing a schematic configuration of a general recording / reproducing system which performs phase encoding multiplexing.

FIG. 52 is an explanatory diagram showing how interference fringes are formed on a hologram recording medium due to interference between information light and reference light.

FIG. 53 is an explanatory diagram showing a state of a pickup at the time of servo in the third embodiment of the present invention.

FIG. 54 is an explanatory diagram showing a state of light near an optical disc when recording and reproducing are performed using a normal optical disc by the optical information recording / reproducing apparatus according to the third embodiment of the present invention.

FIG. 55 is an explanatory diagram showing a state of a pickup at the time of recording according to a third embodiment of the present invention.

FIG. 56 is an explanatory diagram showing a state of light near an optical information recording medium during recording in a third embodiment of the present invention.

FIG. 57 is an explanatory diagram showing a state of light near an optical information recording medium during recording according to the third embodiment of the present invention.

FIG. 58 is an explanatory diagram showing a state of a pickup at the time of fixing according to a third embodiment of the present invention.

FIG. 59 is an explanatory diagram showing a state of light near an optical information recording medium at the time of fixing according to the third embodiment of the present invention.

FIG. 60 is an explanatory diagram showing a state of a pickup during reproduction according to the third embodiment of the present invention.

FIG. 61 is an explanatory diagram showing a state of light near an optical information recording medium during reproduction in a third embodiment of the present invention.

FIG. 62 is an explanatory diagram showing a state of light near an optical information recording medium during reproduction according to the third embodiment of the present invention.

FIG. 63 is an explanatory diagram for describing a direct read-after-write function and a write power control function at the time of multiplex recording of an optical information recording / reproducing apparatus according to a third embodiment of the present invention. .

FIG. 64 is a block diagram showing a circuit configuration necessary for performing collation in the optical information recording / reproducing apparatus according to the third embodiment of the present invention.

FIG. 65 is an explanatory diagram illustrating an example of a distributed recording method according to the third embodiment of the present invention.

FIG. 66 is an explanatory diagram showing another example of the distributed recording method according to the third embodiment of the present invention.

FIG. 67 is an explanatory diagram showing still another example of the distributed recording method according to the third embodiment of the present invention.

FIG. 68 is an explanatory diagram illustrating an example of an arrangement of a plurality of interference regions used in the distributed recording method according to the third embodiment of the present invention.

FIG. 69 is an explanatory diagram showing another example of the arrangement of a plurality of interference areas used in the distributed recording method according to the third embodiment of the present invention.

FIG. 70 is an explanatory diagram for describing a distributed recording method in a case where a plurality of data are multiplex-recorded using shift multiplexing in the third embodiment of the present invention.

FIG. 71 is an explanatory diagram for describing a distributed recording method in a case where a plurality of data are multiplex-recorded using both phase encoding multiplexing and shift multiplexing in the third embodiment of the present invention.

FIG. 72 is a perspective view showing an external appearance of a juke apparatus as an application example of the optical information recording / reproducing apparatus according to the third embodiment of the present invention.

73 is a block diagram showing a circuit configuration of the juke device shown in FIG. 72.

FIG. 74 is an example of a configuration of a main part in a case where a modulation pattern of a phase of a reference light is created based on information unique to an individual in the optical information recording / reproducing apparatus according to the third embodiment of the present invention. FIG.

FIG. 75 is a perspective view showing a schematic configuration of a recording / reproducing system in conventional digital volume holography.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical information recording medium, 2 ... Transparent substrate, 3 ... Hologram layer, 4 ... Protective layer, 5 ... Reflection film, 6 ... Address servo area, 7 ... Data area, 10 ... Optical information recording / reproducing apparatus,
11: Pickup, 12: Objective lens, 14: Two-part optical rotation plate, 17: Phase spatial light modulator, 18: Spatial light modulator, 20: CCD array, 25: Light source device.

Claims (27)

[Claims] 1. An optical information recording apparatus for recording information on an optical information recording medium having an information recording layer on which information is recorded by using holography, comprising: an information beam generating information beam; Information light generating means, and a phase modulating means for spatially modulating the phase of light, a recording reference light generating means for generating a recording reference light whose phase is spatially modulated by the phase modulating means, The information light generated by the information light generating means and the information light generated by the recording reference light generating means so that information is recorded on the information recording layer by an interference pattern due to interference between the information light and the recording reference light. An optical information recording device, comprising: a recording optical system for irradiating the information recording layer with the recording reference light from the same surface side. 2. An optical information recording medium having a positioning area in which information for positioning an information light and a recording reference light is recorded, and further using information recorded in the positioning area. 2. The optical information recording apparatus according to claim 1, further comprising: position control means for controlling the positions of the information light and the recording reference light with respect to the optical information recording medium. 3. The recording optical system irradiates the information light and the recording reference light such that the optical axis of the information light and the optical axis of the recording reference light are arranged on the same line. Claim 1
The optical information recording device according to the above. 4. The information light generating means generates information light in a plurality of wavelength ranges, and the recording reference light generating means generates the recording reference light in the same plurality of wavelength ranges as the information light. 2. The optical information recording apparatus according to claim 1, wherein: 5. A control means for controlling the information light generating means and the recording reference light generating means, and recording information on the optical information recording medium in a redundant manner. The optical information recording device according to claim 1. 6. An optical information recording method for recording information on an optical information recording medium having an information recording layer on which information is recorded by using holography, comprising: generating an information light carrying information; And spatially modulating the phase of light to generate a spatially modulated recording reference light, wherein the information light and the recording reference light are flush with the information recording layer. Irradiating from the side to record information on the information recording layer by an interference pattern due to interference between the information light and the recording reference light. 7. An optical information device having an information recording layer in which information is recorded by an interference pattern caused by interference between an information light carrying information and a recording reference light whose phase is spatially modulated using holography. An optical information reproducing apparatus for reproducing information from a recording medium, comprising: a phase modulating means for spatially modulating a phase of light; and a reproducing reference light having a phase spatially modulated by the phase modulating means. A reproducing reference light generating means for generating; and irradiating the information recording layer with the reproducing reference light generated by the reproducing reference light generating means, and irradiating the information recording layer with the reproducing reference light. A reproduction optical system for collecting reproduction light generated from the recording layer from the same side as the side on which the information recording layer is irradiated with the reproduction reference light; and detecting the reproduction light collected by the reproduction optical system. An optical information reproducing apparatus, comprising: 8. An optical information recording medium having a positioning area in which information for positioning a reference beam for reproduction is recorded, and further using the information recorded in the positioning area, 8. The optical information reproducing apparatus according to claim 7, further comprising a position control means for controlling a position of the reproduction reference light with respect to the optical information recording medium. 9. The reproduction optical system performs irradiation of the reproduction reference light and collection of the reproduction light such that the optical axis of the reproduction reference light and the optical axis of the reproduction light are arranged on the same line. 8. The optical information reproducing apparatus according to claim 7, wherein: 10. The reproduction reference light generating means generates reproduction reference light in a plurality of wavelength ranges, and the detecting means detects reproduction light in the same plurality of wavelength ranges as the reproduction reference light. 8. The optical information reproducing apparatus according to claim 7, wherein: 11. An optical information device having an information recording layer on which information is recorded by an interference pattern caused by interference between an information beam carrying information and a recording reference beam whose phase is spatially modulated using holography. An optical information reproducing method for reproducing information from a recording medium, comprising: spatially modulating a phase of light to generate a spatially modulated reproduction reference light; While irradiating the information recording layer, the reproduction light generated from the information recording layer by irradiating the reproduction reference light is irradiated with the reproduction reference light to the information recording layer. An optical information reproducing method characterized in that the optical information reproducing method collects from the same side as the above and detects the collected reproducing light. 12. An optical information recording medium having an information recording layer on which information is recorded by utilizing holography while causing a change in light absorption at a wavelength position of incident light in a light absorption spectrum. An optical information recording apparatus for performing, the wavelength of light to irradiate the information recording layer, a wavelength selecting means to select from a plurality of wavelengths, having a wavelength selected by the wavelength selecting means, An information light generating means for generating an information light carrying the same; a recording reference light generating means for generating a recording reference light having a wavelength selected by the wavelength selecting means; and an information light and a recording light on the information recording layer. The information light generated by the information light generating means and the recording reference light generated by the recording reference light generating means so that information is recorded by an interference pattern due to interference with the reference light. Steal, optical information recording apparatus characterized by comprising a recording optical system for irradiating from the same side with respect to the information recording layer. 13. An optical information recording medium having a positioning area in which information for positioning an information light and a recording reference light is recorded, and further using information recorded in the positioning area. 13. The optical information recording apparatus according to claim 12, further comprising position control means for controlling positions of the information light and the recording reference light with respect to the optical information recording medium. 14. The recording optical system irradiates the information light and the recording reference light such that the optical axis of the information light and the optical axis of the recording reference light are arranged on the same line. The optical information recording device according to claim 12. 15. A method for recording information on an optical information recording medium having an information recording layer on which information is recorded using holography while causing a change in light absorption at a wavelength position of incident light in a light absorption spectrum. An optical information recording method for performing, the wavelength of the light to irradiate the information recording layer is selected from a plurality of wavelengths, having a selected wavelength, to generate information light carrying information, Generating a recording reference light having a selected wavelength, irradiating the information light and the recording reference light from the same side with respect to the information recording layer, and recording the information light and the information light on the information recording layer. 1. An optical information recording method, wherein information is recorded by an interference pattern caused by interference with a reference light for use. 16. Interference between information light carrying information having a wavelength selected from a plurality of wavelengths and recording reference light having a wavelength selected from a plurality of wavelengths using holography. An optical information reproducing apparatus for reproducing information from an optical information recording medium having an information recording layer on which information is recorded by an interference pattern, wherein the wavelength of light applied to the information recording layer is a plurality of wavelengths. Wavelength selecting means for selecting from among the following; reproducing reference light generating means for generating a reproducing reference light having a wavelength selected by the wavelength selecting means; reproducing reference light generated by the reproducing reference light generating means And irradiating the information recording layer with the reproduction light generated from the information recording layer by irradiating the information recording layer with the reproduction reference light. An optical information reproducing apparatus, comprising: a reproducing optical system that collects light from the same side as a light emitting side; and a detection unit that detects reproduction light collected by the reproducing optical system. 17. The optical information recording medium having a positioning area in which information for positioning a reference beam for reproduction is recorded, and further using the information recorded in the positioning area, 17. The optical information reproducing apparatus according to claim 16, further comprising position control means for controlling the position of the reproduction reference light with respect to the optical information recording medium. 18. The reproducing optical system performs irradiation of the reproducing reference light and collection of the reproducing light such that the optical axis of the reproducing reference light and the optical axis of the reproducing light are arranged on the same line. 17. The optical information reproducing apparatus according to claim 16, wherein: 19. Interference between information light carrying information having a wavelength selected from a plurality of wavelengths and recording reference light having a wavelength selected from a plurality of wavelengths using holography. An optical information reproducing method for reproducing information from an optical information recording medium having an information recording layer in which information is recorded by an interference pattern, wherein a wavelength of light applied to the information recording layer is a plurality of wavelengths. Generating a reference light for reproduction having a selected wavelength, irradiating the information recording layer with the reference light for reproduction, and irradiating the reference light for reproduction with the information recording layer. An optical information reproducing method, comprising: collecting reproduction light generated from a layer from the same side as the side on which the information recording layer is irradiated with the reproduction reference light; and detecting the collected reproduction light. 20. A method for recording information on an optical information recording medium having an information recording layer on which information is recorded by utilizing holography while causing a change in light absorption at a wavelength position of incident light in a light absorption spectrum. An optical information recording apparatus for performing, the wavelength of light to irradiate the information recording layer, a wavelength selecting means to select from a plurality of wavelengths, having a wavelength selected by the wavelength selecting means, Information light generating means for generating information light carrying the light, and phase modulation means for spatially modulating the phase of light, having a wavelength selected by the wavelength selection means, and having a phase selected by the phase modulation means. Recording reference light generating means for generating a spatially modulated recording reference light; and so that information is recorded on the information recording layer by an interference pattern due to interference between the information light and the recording reference light. A recording optical system for irradiating the information recording layer with the information light generated by the information light generating means and the recording reference light generated by the recording reference light generating means from the same surface side. An optical information recording device characterized by the above-mentioned. 21. An optical information recording medium having a positioning area in which information for positioning an information light and a recording reference light is recorded, and further using information recorded in the positioning area. 21. The optical information recording apparatus according to claim 20, further comprising position control means for controlling positions of the information light and the recording reference light with respect to the optical information recording medium. 22. The recording optical system irradiates the information light and the recording reference light such that the optical axis of the information light and the optical axis of the recording reference light are arranged on the same line. The optical information recording device according to claim 20. 23. Recording of information on an optical information recording medium having an information recording layer on which information is recorded by utilizing holography while causing a change in light absorption at a wavelength position of incident light in a light absorption spectrum. An optical information recording method for performing, the wavelength of the light to irradiate the information recording layer is selected from a plurality of wavelengths, having a selected wavelength, to generate information light carrying information, Spatially modulating the phase of the light, having a selected wavelength,
And generating a recording reference light whose phase is spatially modulated, irradiating the information light and the recording reference light with respect to the information recording layer from the same surface side, and information is recorded on the information recording layer. An optical information recording method, wherein information is recorded by an interference pattern caused by interference between light and a recording reference light. 24. An information light carrying information having a wavelength selected from a plurality of wavelengths using holography, and a spatial light having a wavelength selected from a plurality of wavelengths and having a phase spatially. An optical information reproducing apparatus for reproducing information from an optical information recording medium including an information recording layer in which information is recorded by an interference pattern due to interference with a modulated recording reference beam, the information recording layer being irradiated with the information. Wavelength selecting means for selecting a wavelength of light to be selected from a plurality of wavelengths, and phase modulating means for spatially modulating the phase of the light, having a wavelength selected by the wavelength selecting means, and A reproducing reference light generating means for generating a reproducing reference light whose phase is spatially modulated by a modulating means; and irradiating the information recording layer with the reproducing reference light generated by the reproducing reference light generating means. Along with A reproduction optical system that collects reproduction light generated from the information recording layer by being irradiated with the reproduction reference light from the same surface side as the side on which the information recording layer is irradiated with the reproduction reference light. An optical information reproducing apparatus, comprising: a detecting unit configured to detect reproduction light collected by the reproduction optical system. 25. As the optical information recording medium, one having a positioning area in which information for positioning a reference beam for reproduction is recorded, and further using the information recorded in the positioning area, 25. The optical information reproducing apparatus according to claim 24, further comprising a position control means for controlling a position of the reproduction reference light with respect to the optical information recording medium. 26. The reproduction optical system according to claim 22, wherein the reproduction optical system irradiates the reproduction reference light and collects the reproduction light such that the optical axis of the reproduction reference light and the optical axis of the reproduction light are arranged on the same line. 25. The optical information reproducing apparatus according to claim 24, wherein: 27. An information beam having a wavelength selected from a plurality of wavelengths and carrying information by using holography;
Information is read from an optical information recording medium having an information recording layer in which information is recorded by an interference pattern due to interference with a recording reference light having a wavelength selected from a plurality of wavelengths and having a spatially modulated phase. An optical information reproducing method for reproducing, wherein a wavelength of light applied to the information recording layer is selected from a plurality of wavelengths, a phase of the light is spatially modulated, and the selected wavelength is used. And
And generating a reproduction reference beam whose phase is spatially modulated, irradiating the information recording layer with the reproduction reference beam, and irradiating the reproduction reference beam with the reproduction reference beam. An optical information reproducing method, comprising: collecting generated reproduction light from the same side as the side on which the information recording layer is irradiated with the reproduction reference light; and detecting the collected reproduction light.