JP2008176902A - Optical information recording medium - Google Patents

Abstract

To stably record or reproduce information with a simple configuration.
In an optical information recording medium 120, a recording light beam L22c is condensed at a target position by an optical information recording / reproducing apparatus 20 and heated to a recording layer 121 in which an organometallic compound is mixed and photocured in advance. Thus, a cavity is formed in the vicinity of the target position to form a recording mark RM having a high reflectance due to a difference in refractive index, and a return light beam L23 having a sufficient amount of light reflected by the recording mark RM is detected. By doing so, the information represented by the presence or absence of the recording mark RM can be read stably.
[Selection] Figure 12

Description

  The present invention relates to an optical information recording medium, and is suitable for application to an optical information recording medium in which information is recorded using, for example, a light beam and the information is reproduced using the light beam.

  Conventionally, disk-shaped optical disks have been widely used as optical information recording media, and generally used are CD (Compact Disc), DVD (Digital Versatile Disc), Blu-ray Disc (registered trademark, hereinafter referred to as BD), and the like. It has been.

  On the other hand, in an optical disc apparatus corresponding to such an optical disc, various kinds of information such as various contents such as music contents and video contents or various data for computers are recorded on the optical disc. In particular, in recent years, the amount of information has increased due to higher definition of video and higher sound quality of music, and an increase in the number of contents to be recorded on one optical disc has been demanded. It has been demanded.

Therefore, as one of the techniques for increasing the capacity of an optical disk, there has been proposed one in which information is recorded by forming a minute hologram in a recording medium by interfering with two light beams. (For example, refer to Patent Document 1).
JP 2006-78834 A (FIG. 1)

  However, an optical disc apparatus using such an optical disc requires sophisticated control such as simultaneously adjusting the focal positions of two types of light beams at a location where information on the rotating and oscillating optical disc is to be recorded, which complicates the configuration. There is a problem that it is difficult to record or reproduce stable information.

  The present invention has been made in view of the above points, and intends to propose an optical information recording medium capable of stably recording or reproducing information with a simple configuration.

  In order to solve such a problem, the optical information recording medium of the present invention is made of a resin having photopolymerizability, photocrosslinkability or both, and after the resin is cured by irradiation with predetermined initialization light, During recording of information, a predetermined recording light is collected and the temperature in the vicinity of the focal point of the recording light rises to form a cavity as a recording mark, and return light corresponding to irradiation of the predetermined reading light during information reproduction Based on this, a recording layer for reproducing the information is provided.

  The optical information recording medium forms a recording mark by a cavity when the recording light is collected, and the reading light is caused by a difference in refractive index between the resin and the cavity when the recording mark is irradiated with the reading light. And a high-quality reproduction signal can be obtained based on whether or not the readout light is reflected.

  According to the present invention, the recording mark is formed by the cavity when the recording light is condensed, and the reading light is caused by the difference in refractive index between the resin and the cavity when the recording light is irradiated with the reading light. An optical information recording medium capable of obtaining a high-quality reproduction signal based on whether or not the readout light is reflected and thus capable of stably recording or reproducing information with a simple configuration can be realized. .

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) First Embodiment (1-1) Configuration of Optical Information Recording / Reproducing Device In FIG. 1, the optical information recording / reproducing device 1 according to the first embodiment as a whole applies light to the optical information recording medium 100. Is recorded, and the information is reproduced.

  The optical information recording / reproducing apparatus 1 is configured to perform overall control by a control unit 2 having a CPU (Central Processing Unit) configuration, and a basic program, an information recording program, and information reproduction from a ROM (Read Only Memory) (not shown). By reading various programs such as programs and developing them in a RAM (Random Access Memory) (not shown), various processes such as an information recording process and an information reproducing process are executed.

  The control unit 2 controls the initialization light source 3 to emit the initialization light L1 having a wavelength of, for example, 532 [nm] from the initialization light source 3, and the initialization light L1 is fixed on the table 4 The optical information recording medium 100 is irradiated with light.

  Incidentally, as the initialization light source 3, a light source capable of irradiating a high optical power such as a solid-state laser or a semiconductor laser is used.

  The initialization light source 3 has a drive unit (not shown), and can move freely in the x direction (right direction in the figure) and the y direction (front direction in the figure) under the control of the control unit 2, thereby providing optical information. The initialization light L1 can be uniformly applied to the recording medium 100 from an appropriate position.

  On the other hand, the control unit 2 controls the optical pickup 5 so that the optical information recording medium 100 is irradiated with light from the optical pickup 5 and the light returned from the optical information recording medium 100 is received. Has been made.

  The optical pickup 5 emits, for example, a light beam L2 having a wavelength of 532 [nm] from the recording / reproducing light source 10 formed of a laser diode based on the control of the control unit 2, and the collimator lens 11 converts the light beam L2 from divergent light into parallel light. After being converted to, the beam is made incident on the beam splitter 12.

  Incidentally, the recording / reproducing light source 10 can adjust the light amount of the light beam L2 in accordance with the control of the control unit 2.

  The beam splitter 12 transmits part of the light beam L2 through the reflection / transmission surface 12S and makes it incident on the objective lens 13. The objective lens 13 focuses the light beam L2 in the optical information recording medium 100 by condensing the light beam L2.

  Further, when the return light beam L3 returns from the optical information recording medium 100, the objective lens 13 converts the return light beam L3 into parallel light and makes it incident on the beam splitter 12. At this time, the beam splitter 12 reflects a part of the return light beam L3 by the reflection / transmission surface 12S and makes it incident on the condenser lens.

  The condensing lens 14 condenses the return light beam L3 and focuses it on the light receiving surface of the light receiving element 15. In response to this, the light receiving element 15 detects the light amount of the return light beam L3, generates a detection signal corresponding to the light amount, and sends it to the control unit 2. Thereby, the control part 2 can recognize the detection state of the return light beam L3 based on the detection signal.

  By the way, the optical pickup 5 is provided with a drive unit (not shown), and can be freely moved in the three axial directions of the x direction, the y direction, and the z direction under the control of the control unit 2. In practice, the control unit 2 can adjust the focal position of the light beam L2 to a desired position by controlling the position of the optical pickup 5.

  As described above, the optical information recording / reproducing apparatus 1 can irradiate the optical information recording medium 100 with the initialization light L1, condenses the light beam L2 on an arbitrary position in the optical information recording medium 100, and Further, the returning light beam L3 returning from the optical information recording medium 100 can be detected.

(1-2) Configuration of Optical Information Recording Medium As shown in FIGS. 2A and 2B, the optical information recording medium 100 has a flat recording layer 101 for recording information. The substrate 102 and 103 are sandwiched from both sides.

  The recording layer 101 is made of a photopolymerization type photopolymer, and monomers and oligomers are uniformly dispersed therein. When the recording layer 101 is irradiated with light, the monomer and the oligomer are polymerized (that is, photopolymerized) at the irradiated portion, so that the recording layer 101 becomes a polymer, and the refractive index changes accordingly. In addition, the refractive index of the recording layer 101 may further change due to so-called photocrosslinking that causes “crosslinking” between polymers by light irradiation to increase the molecular weight.

  Incidentally, the photopolymerization type photopolymer constituting the recording layer 101 may be used as a so-called hologram medium in which interference fringes generated when two types of light are caused to interfere with each other are recorded as a hologram. In this case, the interference fringes can be recorded as information on the photopolymerization type photopolymer by changing the refractive index and the reflectance at the portion of the interference fringes where the light intensity is high.

  In practice, a resin having the properties of a photopolymerization type and / or a photocrosslinking type constituting both or a part of the recording layer 101 (hereinafter referred to as a photoreactive resin) is, for example, a radical polymerization compound and a photopolymerization resin. It is comprised from the polymerization initiator, or is comprised from the cation polymerization compound and the cation generation type photoinitiator. In addition, the photoreactive resin and the photopolymerization initiator, of which the photopolymerization initiator, in particular, can be adjusted to a desired wavelength at which the photopolymerization easily occurs by appropriately selecting the material. .

  The substrates 102 and 103 are both glass plates, and are configured to sufficiently transmit the light beam L2 and the return light beam L3 described above. Incidentally, the substrates 102 and 103 have a square or rectangular shape with a length dx in the x direction and a length dy in the y direction of about 30 to 80 [mm], respectively, and thicknesses t2 and t3 in the z direction are about 1 [mm].

  The recording layer 101 is relatively soft due to the nature of the material, and when sandwiched between the substrates 102 and 103, the length dx in the x direction and the length dy in the y direction are about 30 to 30 respectively. It is formed in a thin square plate shape or rectangular plate shape having a thickness t1 in the z direction of about 0.3 to 1.0 [mm] of about 80 [mm].

  As described above, the optical information recording medium 100 is configured to have a thin plate shape as a whole, with the recording layer 101 made of a photopolymerization type photopolymer sandwiched between the transparent substrates 102 and 103.

(1-3) Information Recording and Reproduction Next, information recording on the optical information recording medium 100 by the optical information recording / reproducing apparatus 1 and information reproduction from the optical information recording medium 100 will be described.

  In practice, the optical information recording / reproducing apparatus 1 is roughly divided into the initialization of the optical information recording medium 100 (FIG. 3A), the recording of information on the optical information recording medium 100 (FIG. 3B), and Three-stage processing such as reproduction of information from the optical information recording medium 100 (FIG. 3C) can be performed.

(1-3-1) Initialization of Optical Information Recording Medium The optical information recording / reproducing apparatus 1 initializes the entire optical information recording medium 100 or a part thereof as preparation for recording information on the optical information recording medium 100. It is made to do. In this case, the optical information recording / reproducing apparatus 1 emits the initialization light L1 from the initialization light source 3 from one side of the optical information recording medium 100 as shown in FIG. Perform initialization (precure).

  At this time, in the recording layer 101, a photopolymerization reaction or a photocrosslinking reaction or both reactions (hereinafter collectively referred to as a photoreaction) occur in a portion irradiated with the initialization light L <b> 1. Since it is polymerized and polymerized, the refractive index changes as compared with that before irradiation of the initialization light.

  Incidentally, the recording layer 101 has a uniform refractive index because the photoreaction occurs almost uniformly in the portion irradiated with the initialization light L1. That is, in the optical information recording medium 100, for example, when the light quantity of the return light when irradiated with light and the code “0” or “1” are associated with each other, the optical information recording medium 100 is uniform in any part of the optical information recording medium 100 at this stage. Since the code is “0” (or “1”), no information is recorded. Therefore, the optical information recording / reproducing apparatus 1 also preformats the optical information recording medium 100.

  The initialization light source 3 is not limited to irradiating the initialization light L1 simultaneously over an area equivalent to that of the optical information recording medium 100. For example, the initialization light source 3 is a small initialization that emits the initialization light L1 over a relatively small area. Initializing only a part of the optical information recording medium 100 using a light source, or initializing the entire recording layer 101 by appropriately moving the small initialization light source with respect to the optical information recording medium 100, etc. You may do it.

  Incidentally, in the optical information recording / reproducing apparatus 1, it is conceivable to collect the initialization light L1 with a lens or the like and irradiate the recording layer 101. However, in order to achieve uniform initialization, the initialization light L1 is converted into parallel light. It is desirable to irradiate the recording layer 101 as it is. Further, as the initialization light source 3, it is possible to use a light source capable of irradiating high light power such as a high-pressure mercury lamp (for example, a main wavelength component 365 [nm]), a high-pressure meta-harara lamp, a solid-state laser, or a semiconductor laser.

(1-3-2) Information Recording When the optical information recording / reproducing apparatus 1 records information on the optical information recording medium 100, as shown in FIG. 3B, the recording light beam L2 ( Hereinafter, this is referred to as a recording light beam L2c) and condensed in the recording layer 101. In this case, the optical information recording / reproducing apparatus 1 controls the positions of the optical pickup 5 (FIG. 1) in the x direction, the y direction, and the z direction, thereby causing the recording light beam L2c (FIG. 3B) to be recorded on the recording layer 101. Is focused on a target position (hereinafter referred to as a target position).

  At this time, at the target position in the recording layer 101, the recording light beam L2c is condensed, whereby the temperature locally rises and the photopolymer is altered.

  Here, when a simulation of a temperature change in the optical information recording medium 100 in which photopolymerization was completed by initialization was performed, temperature distribution characteristics as shown in FIG. 4 were obtained.

In this simulation, the thermal conductivity of the photopolymer is 0.20 [W / mK], the temperature diffusivity is 7.4 × 10 ⁻⁸ [m ² / sec], and the absorption coefficient at a wavelength of 532 [nm] is 2 × 10 ⁻⁴ . Further, the NA (Numerical Aperture) of the objective lens 13 is 0.5, the wavelength of the recording light beam L2c is 532 [nm], the optical power is 500 [mW], and the recording is performed at a room temperature of 25 [° C.]. The temperature distribution in the z direction centered on the target position when the light beam L2c was irradiated for 1 [μsec] was calculated.

  From FIG. 4, in the optical information recording medium 100, the recording light beam L2c is irradiated, so that the temperature is about 180 [° C.] in a local range of about 4 [μm] centered on the target position. It can be seen that the high temperature is exceeded. Since the photopolymer constituting the recording layer 101 is assumed to have a glass transition point in the vicinity of about 100 [° C.] to 120 [° C.], the temperature in the vicinity of the target position surely exceeds the glass transition point. It is considered that some state change has occurred. In this case, in addition to the increase in temperature, there is a possibility that the recording light beam L2c is emitted as light.

  Further, when the recording layer 101 contains an organic metal compound or an inorganic metal compound, in the optical information recording medium 100, the temperature in the vicinity of the focal point is efficiently raised by the organic metal compound or the inorganic metal compound due to heat during light collection. It is also assumed. Alternatively, it is assumed that in the recording layer 101, the organometallic compound or the inorganic metal compound is altered to produce a metal compound, and the metal compound efficiently raises the temperature in the vicinity of the focal point.

  Further, in the optical information recording medium 100, it is considered that the material constituting the recording layer 101 has been altered by the photochemical reaction by the recording light beam L2c, or by both the photochemical reaction and the thermochemical reaction, thereby creating a cavity. At this time, in the optical information recording medium 100, it is assumed that the photochemical reaction or thermochemical reaction is promoted by the organometallic compound, the inorganic metal compound, or the generated metal compound.

  In any case, the cavity formed in the vicinity of the target position in the optical information recording medium 100 has a refractive index different from that of the surrounding material (that is, the material constituting the recording layer 101). The rate will be increased.

  As a result, as shown in FIG. 3B, a recording mark RM formed by altering the photopolymer is formed near the target position. Incidentally, it was difficult to visually confirm the recording mark RM.

  Actually, the optical information recording / reproducing apparatus 1 records the recording mark RM, for example, when the binarized information has the value “1”, and does not record the recording mark RM when the information has the value “0”. By associating, information can be recorded on the optical information recording medium 100.

(1-3-3) Information Reproduction When the optical information recording / reproducing apparatus 1 reads information from the optical information recording medium 100, as shown in FIG. Is referred to as a read light beam L2d) in the recording layer 101. In this case, the optical information recording / reproducing apparatus 1 controls the positions of the optical pickup 5 (FIG. 1) in the x direction, the y direction, and the z direction as in the case of recording information, thereby reading the read light beam L2d (FIG. 3). (B)) is focused on the target position in the recording layer 101.

  When a return light beam L3 (hereinafter also referred to as reproduction light) returns from the optical information recording medium 100, the optical information recording / reproducing apparatus 1 returns the return light beam L3 via the objective lens 13, the beam splitter 12, and the like. Is detected by the light receiving element 15.

  Here, when the recording mark RM is not recorded at the target position of the optical information recording medium 100, that is, when the target position remains in the initialized state, the light receiving element 15 is shown in FIG. As described above, a very weak return light beam L3 was detected. Incidentally, in FIGS. 5A to 5C, the portion where the return light beam L3 is strong is shown in white, and the weak portion is shown in black.

  On the other hand, when the recording mark RM is recorded at the target position of the optical information recording medium 100, the light receiving element 15 detects the return light beam L3 having a very strong luminance as shown in FIG. I was able to.

In FIG. 5B, when initializing the optical information recording medium 100, the wavelength of the initialization light L1 is 532 [nm], the optical power density is 2 [mW / cm ² ], and the initialization time is 30 [min. ], The wavelength of the light beam L2 used for recording and reproducing information is similarly 532 [nm], the NA of the objective lens 13 is 0.5, and the optical power of the recording light beam L2c is 450 [mW]. The light reception result when the recording time is 1 [sec] and the optical power of the reading light beam L2d is 50 [μW] is shown.

  Incidentally, the return light beam L3 from the recording mark RM detected by the light receiving element 15 is compared with reproduction light that can be detected when a general μ (micro) hologram is formed on the optical information recording medium 100, It has a strong brightness.

  As described above, the optical information recording / reproducing apparatus 1 initializes the optical information recording medium 100 and performs an information recording operation on the target position, thereby recording information in the form of improving the reflectance at the target position. Further, it was confirmed that the recorded information can be reproduced by performing the information reproduction operation on the target position.

  In this case, in the optical information recording medium 100, the portion of the photopolymer constituting the recording layer 101 where the recording light beam L2c is condensed and the temperature is locally increased (that is, near the target position) is altered, and the refractive index is changed. As a result of the change, it is considered that the reflectance is improved (that is, the recording mark RM is formed).

  Here, when the distribution of the light intensity of the return light beam L3 formed by reflecting the reading light beam L2d by the recording mark RM is measured in the x direction, the y direction, and the z direction, respectively, FIGS. 6A and 6B show. The results shown were obtained. Here, the characteristic curves Sx, Sy, and Sz indicate signal intensities obtained by the light receiving element 15 when the focus of the reading light beam L2d is displaced with respect to the x direction, the y direction, and the z direction, respectively, around the target position (that is, (Light intensity) distribution.

  In this case, the optical information recording / reproducing apparatus 1 initializes the optical information recording medium 100 in which the thickness t1 of the recording layer 101 is 0.3 [mm] with the laser light in the case of FIG. Thereafter, the position of 0.1 [mm] in the z direction from the boundary surface between the recording layer 101 and the substrate 102 is set as a target position, the NA of the objective lens 13 is set to 0.4, and the wavelength of the recording light beam L2c is set to 532. The recording mark RM was recorded with [nm], optical power 90 [mW], and recording time 3 [sec]. In the optical information recording / reproducing apparatus 1, the wavelength of the reading light beam L2d is 532 [nm] and the optical power is 7 [μW].

  From the distribution characteristics shown in FIGS. 6A and 6B, the recording mark RM is formed in a shape that approximates an ellipsoid as a whole, the diameter in the xy plane is about 1 [μm], and the height in the z direction. Is about 10 [μm].

  Actually, the optical information recording / reproducing apparatus 1 records at the target position when it detects that the signal intensity is high and the recording mark RM is recorded at the target position based on the signal intensity of the return light beam L3. When the detected information is recognized as the value “1” and it is detected that the signal strength is low and the recording mark RM is not recorded at the target position, the information recorded at the target position is the value “0”. ", The information recorded on the optical information recording medium 100 can be read out.

  Incidentally, the portion of the recording layer 101 where the photopolymerization type photopolymer is altered to change the reflectance, that is, the portion where the recording mark RM is formed is localized near the focal point of the recording light beam L2c. Accordingly, the optical information recording / reproducing apparatus 1 can form the recording mark RM smaller as the numerical aperture (NA) of the objective lens 13 is increased when the performance of the diffraction limit by the objective lens 13 is obtained. The recording density in the layer 101 can be improved.

On the other hand, experimentally, when an LED (Light Emitting Diode) was used as the initialization light source 3 instead of the laser, a relatively weak return light beam L3 could be detected as shown in FIG. 5C. . In FIG. 5C, when the optical information recording medium 100 is initialized, a green LED is used as the initialization light source 3, the optical power density is 2 [mW / cm ² ], and the initialization time is 60 [min. ], And the light reception result when the recording light beam L2c and the reading light beam L2d are the same as in the case of FIG. 5B is shown.

  In this case, as is apparent from FIG. 5C, the result is that the intensity of the return light beam L3 is weak and the SNR (Signal to Noise Ratio) is deteriorated.

  Also, in the optical information recording / reproducing apparatus 1, the optical information recording medium 100 is not initialized, and when recording information, the recording light beam L2c is condensed at the target position and irradiated to photopolymerize the monomer. Although a method of forming a recording mark RM by polymerizing and further changing the temperature by the recording light beam L2c to form a recording mark RM is conceivable, it is difficult to record stable information because the recording conditions change temporally and spatially. It is expected to be.

  As described above, in the optical information recording medium 100 according to the first embodiment, when the initialization process is performed using the laser light, the change in reflectance at the portion where the recording light beam L2c is focused is most remarkable. It was confirmed to appear in

(1-3-4) Reproduction of Multi-layer Recording Next, the target position in the z direction is stepped with respect to the optical information recording medium 100 that has been subjected to the initialization process similar to that shown in FIG. The recording marks RM are arranged in a three-dimensional direction to perform multi-layer recording (so-called volume type recording), and the return light beam L3 (that is, reproduction light) from each recording mark RM at this time is measured.

  Specifically, first, the optical information recording / reproducing apparatus 1 changes the target position in the recording layer 101 in the three-dimensional direction by changing the position of the optical pickup 5 in the x direction, the y direction, and the z direction. The recording mark RM was recorded in layers over the layers. In this case, the interval between the recording marks RM on the xy plane in each layer (hereinafter referred to as a mark recording layer) was 5 [μm], and the interval between the mark recording layers was 30 [μm].

  Next, the optical information recording / reproducing apparatus 1 irradiates each mark recording layer of the optical information recording medium 100 so as to focus the reading light beam L2d, and detects the return light beam L3. The detection results of the return light beam L3 in the first layer (side closest to the substrate 102), the third layer, the fifth layer, the seventh layer, and the ninth layer at this time are shown in FIGS. (C) and FIG. 8 (A) and FIG. 8 (B), respectively.

  Incidentally, in FIGS. 7A to 7C and FIGS. 8A and 8B, the signal intensity is shown in the vertical axis direction and the position in the x direction is shown in the horizontal axis direction, and reading is performed in each mark recording layer. The measurement results of the signal intensity when the focal position of the light beam L2d is moved in the x direction are shown.

  As is clear from FIGS. 7A to 7C and FIGS. 8A and 8B, for any mark recording layer from the first layer to the tenth layer in the optical information recording medium 100, The difference in signal intensity between the portion where the recording mark RM is formed and the portion where the signal mark RM is not formed (a portion where only the initialization is performed) appears remarkably.

  That is, the optical information recording / reproducing apparatus 1 detects a recording mark RM recorded in each layer as a return light beam L3 having a necessary and sufficient signal intensity when a mark recording layer is formed by at least 10 layers by multilayer recording. Thus, it is possible to obtain a good reproduction signal and to read out the presence or absence of each recording mark RM, that is, whether the value “0” or the value “1” is recorded as information with high accuracy.

(1-4) Operation and Effect In the above configuration, the optical information recording / reproducing apparatus 1 according to the first embodiment first applies to the optical information recording medium 100 having the recording layer 101 made of a photopolymerization type photopolymer. Initialization processing is performed in advance by irradiating the initialization light L1 entirely or partially from the initialization light source 3.

  Next, the optical information recording / reproducing apparatus 1 records the recording mark RM by condensing the recording light beam L2c having a relatively strong light intensity with respect to the target position in the recording layer 101 in the optical information recording medium 100, Thereafter, the reading light beam L2d having a relatively weak light intensity with respect to the target position is condensed, and the return light beam L3 having a sufficient amount of light reflected by the recording mark RM is received.

  Therefore, the optical information recording / reproducing apparatus 1 can reliably record the recording mark RM by irradiating the initialization light L1 and initializing the recording layer 101 of the optical information recording medium 100 in advance. It can be read correctly.

  In this case, the optical information recording / reproducing apparatus 1 causes the recording mark 101 by performing a photoreaction, that is, a photopolymerization reaction, a photocrosslinking reaction, or both, in the recording layer 101 made of a photopolymerization type photopolymer as an initialization process. It is possible to achieve a state suitable for RM formation, that is, it is possible to “create a base for information recording”.

  Further, the optical information recording / reproducing apparatus 1 condenses the recording light beam L2c with respect to the target position of the recording layer 101, and irradiates light by raising the vicinity of the target position to a very high temperature or in addition to the high temperature. As a result, the photopolymerizable photopolymer can be altered (FIG. 4), and as a result, a recording mark RM with a high light reflectance can be formed and recorded as information.

  For this reason, when the optical information recording / reproducing apparatus 1 irradiates the optical information recording medium 100 with the reading light beam L2d, the optical information recording / reproducing apparatus 1 starts from the recording mark RM at a portion where the recording mark RM is not formed, that is, initialized. Compared with the point, the extremely strong return light beam L3 can be detected. In other words, the optical information recording / reproducing apparatus 1 can obtain a reproduction signal having an extremely high SNR from the optical information recording medium 100, and can reproduce information with high accuracy and stability.

  Furthermore, the optical information recording / reproducing apparatus 1 has a sufficient SNR so that the presence / absence of the recording mark RM can be clearly recognized from each layer even when the mark recording layer is formed in multiple layers with respect to the optical information recording medium 100. A reproduction signal can be obtained (FIGS. 7 and 8).

  In this case, the optical information recording / reproducing apparatus 1 forms a plurality of mark recording layers in the recording layer 101 by displacing the focal position of the recording light beam L2c stepwise in the z direction (FIG. 1). Mold recording can be performed. Therefore, the recording layer 101 of the optical information recording medium 100 does not need to be previously formed with a physical layer for mark recording, and a photopolymerizable photopolymer exists uniformly in the z direction (FIG. 2). Therefore, it can be easily manufactured as compared with a case where a recording layer composed of a resin and a reflection film, to which a signal is transferred from a metal stamper, is physically laminated.

  By the way, in general, an optical information recording / reproducing apparatus for forming a hologram in a photopolymerization type photopolymer does not perform a process such as initialization in particular when recording a so-called positive μ hologram, ie, a location for recording information (ie, target By forming a light interference fringe locally with respect to the position), a light reaction is caused only in a portion having a high light intensity in the interference fringe, and the interference fringe is recorded as a hologram.

  In the case of this positive μ hologram, the optical information recording / reproducing apparatus is based on the fact that when reproducing information, the reproducing light returns from the hologram when irradiated with reading light, and no reproducing light is generated from any other part. Whether the value “0” or the value “1” is recorded as information can be recognized.

  In the case of a so-called negative type μ hologram, the optical information recording / reproducing apparatus forms an interference fringe of light over the entire information recording area in the photopolymerization type photopolymer, and performs initialization by recording the interference fringe. Then, the light is locally focused on the location where information is recorded (that is, the target position), thereby raising the temperature of the photopolymerization type photopolymer at the target position and changing the information locally. This will destroy the hologram.

  In the case of this negative μ hologram, when reproducing information, the optical information recording / reproducing apparatus returns that the reproducing light returns from the hologram when the reading light is irradiated, and the reproducing light hardly returns from the location where the hologram is destroyed. Based on this, it is possible to recognize whether the value “0” or the value “1” is recorded as information.

  On the other hand, the optical information recording / reproducing apparatus 1 does not require extremely high-precision servo control for accurately generating light interference fringes as compared with the case of using a hologram, and can simplify the configuration. . In the case of using a hologram, in order to correctly determine the information value “0” or “1”, it is necessary to adjust the sensitivity to light in the optical information recording medium with high accuracy. Such adjustment is unnecessary, and the optical information recording medium 100 can be manufactured relatively easily.

  In addition, the recording and reproduction of information according to the present invention is clearly different from a positive μ hologram in that initialization processing is performed on an optical information recording medium, and the positive recording can be simplified because high-precision servo control is not required. It is more advantageous than a type μ hologram.

  Furthermore, when compared with negative μ holograms, the so-called pre-cure, which causes a uniform photoreaction, and the strong reproduction light returns from the point where the information is recorded by irradiating the recording light. It is not necessary to form a hologram that requires a high degree of control especially during the initialization process, and light of a different wavelength is used for the initialization and for recording or reproduction. It is advantageous over the negative μ hologram in that it can be used.

  For example, when a green laser or a blue laser that emits laser light having the same wavelength as the recording light beam L2c and the reading light beam L2d is used as the initialization light source 3, it is generally difficult to increase the output power. It is highly likely that it takes a long time to initialize. In contrast, in the optical information recording / reproducing apparatus 1 of the present invention, a laser capable of high output can be used as the initialization light source 3 in the wavelength range in which the recording layer 101 reacts. It can be completed in a relatively short time.

  By the way, although a method for performing volume recording using two-photon absorption has been proposed, a recording medium capable of performing stable recording is still under development, and a single pulse high power laser such as a femtosecond laser is required. Therefore, there is a problem that the configuration of the optical information recording / reproducing apparatus is complicated.

  On the other hand, the optical information recording / reproducing apparatus 1 of the present invention can be configured to be similar to a general optical disc apparatus without using a semiconductor laser or the like, and the optical information recording medium 100 is used. Thus, it was possible to actually confirm the recording and reproduction of the recording mark RM.

  In addition, information recording by so-called volume holograms has a problem that it is difficult to suppress the generation of media noise when multiple recording advances, and it is difficult to handle photopolymer media (recording media) that are mainly used, Furthermore, there is a problem that the configuration of the optical information recording / reproducing apparatus becomes complicated because it is necessary to use a spatial modulator or an image sensor composed of multiple pixels. However, in the optical information recording / reproducing apparatus 1 according to the present invention, in principle. These problems do not occur.

  According to the above configuration, the optical information recording / reproducing apparatus 1 according to the first embodiment performs the initialization process on the optical information recording medium 100 having the recording layer 101 made of a photopolymerizable photopolymer in advance, The recording mark RM is recorded by condensing the recording light beam L2c having a relatively strong light intensity with respect to the target position in the recording layer 101 and raising the temperature, and then with a relatively weak light intensity with respect to the target position. The reading light beam L2d is condensed and the return light beam L3 having a sufficient amount of light reflected by the recording mark RM is received, whereby the recording mark RM can be recorded reliably and the recording mark RM can be stabilized. Can be read out automatically.

(2) Second Embodiment (2-1) Configuration of Optical Information Recording / Reproducing Device In FIG. 9 where the same reference numerals are given to the parts corresponding to those in FIG. 1, the optical information recording / reproducing device 20 according to the second embodiment is provided. Are controlled by the control unit 21 corresponding to the control unit 2 (FIG. 1).

  The optical information recording / reproducing apparatus 20 is provided with an optical pickup 25 having a recording / reproducing light source 22 and an objective lens 23 instead of the optical pickup 5 having the recording / reproducing light source 10 and the objective lens 13, and an initialization light source. Although the point 3 is omitted, the rest is configured similarly to the optical information recording / reproducing apparatus 1 (FIG. 1).

(2-2) Configuration of Optical Information Recording Medium On the other hand, in the second embodiment, the optical information recording medium 120 is used instead of the optical information recording medium 100. In this optical information recording medium 120, as shown in FIGS. 10A to 10C, a spacer 124 is sandwiched between substrates 122 and 123, and a recording layer 121 is placed in an internal space 124A provided in the spacer 124. By forming it, it functions as a photopolymer medium as a whole.

  The substrates 122 and 123 are glass substrates like the substrates 102 and 103 in the first embodiment, and transmit light at a high rate. The substrates 122 and 123 have a square plate shape in which the length dx in the x direction and the length dy in the y direction are about 30 to 80 [mm], and the thickness t22 and t23 are about 1.1 [mm], respectively. It is configured as a rectangular plate.

  The spacer 124 has a length dx in the x direction and a length dy in the y direction of about 30 to 80 [mm], respectively, and a thickness t21 of about 0.5 [mm] in accordance with the substrates 122 and 123. It consists of PET (Polyethylene Terephthalate) resin. Further, as shown in FIG. 10A, the spacer 124 has an internal space 124A in which a rectangular cross section penetrates in the z direction, that is, is hollowed in a rectangular parallelepiped shape.

  In the recording layer 121, a liquid material M1 described later is developed in the internal space 124A in a state where the spacer 124 is sandwiched between the substrates 122 and 123, and is irradiated from the initialization light source 81 in the initialization apparatus 80 shown in FIG. The initialization light L21 is initialized. Incidentally, as the initialization light source 81, a light source capable of irradiating high light power such as a high pressure mercury lamp, a high pressure meta-hara lamp, a solid-state laser, or a semiconductor laser can be used as in the initialization light source 3.

  In the recording layer 121, an organic or inorganic metal compound-containing photoreactive resin is uniformly dispersed. When the recording layer 121 is irradiated with light in the stage before initialization, the photoreactive resin polymerizes or crosslinks at the irradiated portion, or both reactions proceed (that is, photoreacts), thereby increasing the molecular weight. Moreover, it has the property (it calls this photoreactivity below) that it hardens | cures and a refractive index changes with this.

Specifically, the recording layer 121 is composed of 40:60 (weight ratio) of acrylic acid ester monomer (p-cumylphenol ethylene oxide-added acrylic acid ester) and urethane bifunctional acrylate oligomer, and a weight ratio of 2% with respect to the monomer and the oligomer. Organometallic compound and photopolymerization initiator (bis (η-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) Titanium (Ciba Specialty Chemicals IRGACURE (registered trademark) -784, hereinafter referred to as Irg-784) is mixed and degassed in the dark room (hereinafter referred to as the liquid material M1), and the internal space 124A of the spacer 124 is obtained. And an initialization light source composed of a high-pressure mercury lamp after being sandwiched between the substrates 122 and 123. Initializing light L21 (power density 30 mW / cm ² at a wavelength of 365 [nm]) is photocured by being 60 [min] illuminated by 1.

  In this initialization process, the recording layer 121 undergoes a photoreaction as a whole, and as in the initialization (precure) process in the first embodiment, the resin photoreacts inside, and the shape of the internal space 124A. Is formed into a thin square plate shape or a rectangular plate shape.

  As a result, the refractive index of the recording layer 121 changes as a whole as compared with that before irradiation of the initialization light. Incidentally, the recording layer 121 is substantially transparent in the photocured state, and transmits the irradiated light at a high rate.

  As described above, the optical information recording medium 120 is configured in a thin plate shape as a whole and substantially transmits light, and the resin in the recording layer 121 is polymerized and / or crosslinked by the initialization process. A small amount of an organometallic compound is included in the recording layer 121.

(2-3) Information Recording and Reproduction Next, information recording on the optical information recording medium 120 and information reproduction from the optical information recording medium 120 in the second embodiment will be described.

  When the optical information recording / reproducing apparatus 20 records information on the optical information recording medium 120, the recording light beam L22c from the recording / reproducing light source 22 (FIG. 9) is applied to the recording layer 121 as shown in FIG. Condenses inside. In this case, the optical information recording / reproducing device 20 controls the positions of the optical pickup 25 (FIG. 9) in the x direction, the y direction, and the z direction, thereby causing the recording light beam L22c (FIG. 12A) to be recorded on the recording layer 121. The target position (namely, the target position) is focused.

  Specifically, the optical information recording / reproducing apparatus 20 uses a position having a depth of 100 [μm] from the surface of the recording layer 121 as a target position, and a laser having a wavelength of 402 [nm] and an optical power of 20 [mW] from the recording / reproducing light source 22. A recording light beam L22c made of light was emitted, condensed by an objective lens 23 with NA (Numerical Aperture) = 0.35, and irradiated to a target position with an irradiation time of 1 [sec].

  When reproducing the information, the optical information recording / reproducing apparatus 20 reads out the light having the same wavelength as the recording light beam L22c from the recording / reproducing light source 22 and the optical power of 200 [μW] as shown in FIG. The beam L22d is emitted and condensed on the recording mark RM in the recording layer 121 by the objective lens.

  At this time, the read light beam L22d is reflected by the recording mark RM to become a return light beam L23. The optical information recording / reproducing apparatus 20 detects the return light beam L23 by a light receiving element 15 formed of a CCD (Charge Coupled Device) through the objective lens 23, the beam splitter 12, and the like.

  As shown in FIG. 13A, the light receiving element 15 was able to detect the return light beam L23 having a high luminance as in the first embodiment (FIG. 5A).

  This is because, in the vicinity of the target position in the recording layer 121, the temperature has locally increased due to the concentration of the recording light beam L22c, so that the organometallic compound is hollow due to thermal reaction or both thermal reaction and photoreaction. Is considered to have occurred.

  That is, in the recording layer 121, a cavity is formed in a portion of the resin containing the organometallic compound where the recording light beam L22c is condensed and locally heated, and the refractive index of the material of the recording layer 121 and the refractive index in the cavity is increased. It is inferred that the reflectivity is improved due to the difference.

  Here, FIG. 14 shows an SEM (Scanning Electron Microscope) image in which a plurality of recording marks RM are formed on the recording layer 121 and the cross section is photographed by a scanning microscope. From FIG. 14, it can be seen that the recording mark RM is a cavity having a shape close to a sphere or spheroid.

  Further, since the interface of each recording mark RM is smooth without any significant unevenness, it is expected that the refractive index will change abruptly, and accordingly, it is also expected to have a very high reflectance.

  Thus, in the vicinity of the target position in the recording layer 121, a hollow recording mark RM is formed, and information is recorded. Incidentally, it was difficult to visually confirm the recording mark RM.

  On the other hand, a very weak return light beam L23 was detected from a portion where the recording mark RM was not recorded (that is, an unrecorded portion) as shown in FIG. That is, as in the first embodiment, when the optical information recording / reproducing apparatus 20 reproduces information from the optical information recording medium 120, the detection intensity of the return light beam L23 varies greatly depending on the presence or absence of the recording mark RM. I understand.

  This is because, for example, the optical information recording / reproducing apparatus 20 can record information on the optical information recording medium 120 by associating the code “0” or “1” with the presence / absence of the recording mark RM and reproduces the information. This indicates that whether or not the recording mark RM is recorded at the target position at that time, that is, whether the code “0” or “1” is recorded as information can be determined with high accuracy.

  As described above, the optical information recording medium 120 is obtained by condensing the recording light beam L22c by the optical information recording / reproducing apparatus 20 and increasing the temperature thereof on the recording layer 121 that is mixed with the organometallic compound and is previously photocured. Information recording for forming a recording mark RM formed of a cavity can be performed. Further, the optical information recording medium 120 can perform information reproduction for detecting the return light beam L23 having high luminance by irradiating the recording mark RM with the reading light beam L22d by the optical information recording / reproducing apparatus 20. .

(2-4) Reproduction of multi-layer recording Next, as with the first embodiment, the optical information recording medium 120 becomes a cavity by changing the position of the target position in the z direction stepwise. Multi-layer recording (that is, volume recording) in which the recording marks RM are arranged in a three-dimensional direction was performed, and the return light beam L3 (that is, reproduction light) from each recording mark RM at this time was measured.

  Specifically, first, the optical information recording / reproducing apparatus 20 changes the target position in the recording layer 121 in the three-dimensional direction by changing the position of the optical pickup 25 in the x direction, the y direction, and the z direction. The recording mark RM was recorded in layers over the layers. In this case, the interval between the recording marks RM on the xy plane in each mark recording layer was 3 [μm], and the interval between the mark recording layers was 22.5 [μm].

  Next, the read information light beam L22d was applied to each mark recording layer of the optical information recording medium 120 by the optical information recording / reproducing apparatus 20 so as to be focused, and the return light beam L23 was detected. Specifically, the wavelength of the recording light beam L22c and the reading light beam L22d used for recording and reproducing information on the optical information recording medium 120 is 405 [nm], and the optical power of the recording light beam L22c is 10 [mW]. The recording time was 2 to 5 [sec], the optical power of the reading light beam L22d was 1 [mW], and the NA of the objective lens 23 was 0.35.

  The detection results of the return light beam L23 in the second layer (side closer to the substrate 102), the fifth layer, the eighth layer, and the eleventh layer at this time are shown in FIGS. 15A and 15B and FIG. And (B) respectively.

  15A and 15B and FIGS. 16A and 16B show the signal intensity in the vertical axis direction and the position in the x direction in the horizontal axis direction, as in FIGS. The measurement results of the signal intensity when the focus position of the reading light beam L22d is moved in the x direction in each mark recording layer are shown.

  As is clear from FIGS. 15A and 15B and FIGS. 16A and 16B, any mark recording layer from the first layer to the twelfth layer in the optical information recording medium 120 is used. The difference in signal intensity between the portion where the recording mark RM is formed and the portion where the signal mark RM is not formed (a portion where only the initialization is performed) appears remarkably.

  That is, in the case where the optical information recording / reproducing apparatus 20 performs multi-layer recording of the mark recording layer over at least 12 layers, the optical information recording medium 120 uses the return light beam having a necessary and sufficient signal intensity as the recording mark RM recorded in each layer. By detecting as L23, a good reproduction signal can be generated, and the presence or absence of each recording mark RM, that is, whether the value “0” or the value “1” is recorded as information is read with high accuracy. be able to.

(2-5) Operation and Effect In the above configuration, the optical information recording / reproducing apparatus 20 according to the second embodiment applies to the recording layer 121 in which the organometallic compound in the optical information recording medium 120 is blended and photocured in advance. Thus, by condensing the recording light beam L22c emitted from the recording / reproducing light source 22 at the target position and increasing the temperature, a cavity is formed in the vicinity of the target position, the reflectance is increased, and the recording mark RM is formed.

  Further, the optical information recording / reproducing apparatus 20 condenses the reading light beam L22d having a relatively weak light intensity with respect to the recording mark RM in the recording layer 121, and a returning light beam having a high luminance reflected by the recording mark RM. L23 is received.

  Therefore, the optical information recording medium 120 can form the recording mark RM in a state where the photoreaction has been completed in advance because the recording layer 121 has been photocured in advance.

  Further, the optical information recording medium 120 contains an organometallic compound in the resin constituting the recording layer 121, so that the reflectance of light is kept low in the portion where it is initialized and the recording light beam L22c is collected. The recording mark RM with high reflectivity can be formed by forming a cavity by being irradiated with light and locally changing in temperature and denatured.

  At this time, since the optical reaction in the recording layer 121 is completed in the optical information recording medium 120, there is no change in the thermal conductivity caused by the change in the ratio of the photoreaction or the occurrence of the photon mode. The temperature in the vicinity of the position can be reliably increased.

  As a result, the optical information recording medium 120 can set the temperature in the vicinity of the target position of the recording layer 121 to be equal to or higher than the boiling point of the resin constituting the recording layer 121, so that the recording mark RM can be reliably formed by generating a cavity. it can.

  Therefore, when the optical information recording medium 120 is irradiated with the reading light beam L22d from the optical information recording / reproducing apparatus 20 at the time of information reproduction, the optical information recording medium 120 is compared with the portion where the recording mark RM is not formed from the portion where the recording mark RM is formed. And an extremely strong return light beam L23 can be detected. In other words, the optical information recording medium 120 can generate a reproduction signal having an extremely high SNR by the optical information recording / reproducing apparatus 20 as in the optical information recording medium 100 in the first embodiment. It can be played back accurately and stably.

  Further, the optical information recording medium 120 is shown in FIGS. 15A and 15B and FIGS. 16A and 16B even when the mark recording layer is recorded in multiple layers over at least 12 layers. As described above, the presence or absence of the recording mark RM recorded in each layer can be read by the optical information recording / reproducing apparatus 20 with high accuracy.

  In addition, the so-called positive μ hologram recording / reproducing apparatus that forms a minute hologram in the recording medium by interfering with the two light beams is greatly limited in temperature and humidity environment especially during recording / reproducing due to the complexity of the configuration. Therefore, there is a restriction that it cannot be handled in the same way as CD media, DVD media, BD media, and the like that are already widely used. On the other hand, in the optical information recording medium 120 according to the present invention, the configuration of the optical information recording / reproducing apparatus 20 can be greatly simplified as compared with the optical disk apparatus, so that the restrictions at the time of recording / reproducing can be greatly reduced. Information can be recorded or reproduced stably.

  According to the above configuration, in the optical information recording medium 120 according to the second embodiment, the recording light beam L22c is recorded by the optical information recording / reproducing apparatus 20 on the recording layer 121 in which the organometallic compound is blended and previously photocured. Is condensed at the target position and heated to form a recording mark RM having a high reflectance by forming a cavity in the vicinity of the target position, and with a sufficient amount of light reflected by the recording mark RM. By detecting the return light beam L23, information represented by the presence or absence of the recording mark RM can be read stably.

(3) Third Embodiment (3-1) Configuration of Optical Information Recording / Reproducing Device In FIG. 17 in which the same reference numerals are assigned to the parts corresponding to those in FIG. 1, the optical information recording / reproducing device 30 according to the third embodiment. Is controlled in a centralized manner by a control unit 31 corresponding to the control unit 2 (FIG. 1).

  The optical information recording / reproducing apparatus 30 is provided with an optical pickup 35 having a recording / reproducing light source 32 and an objective lens 33 in place of the optical pickup 5 having the recording / reproducing light source 10 and the objective lens 13, and an initialization light source. Although the point 3 is omitted, the rest is configured similarly to the optical information recording / reproducing apparatus 1 (FIG. 1).

(3-2) Configuration of Optical Information Recording Medium On the other hand, in the third embodiment, an optical information recording medium 130 is used instead of the optical information recording medium 100. As shown in FIGS. 18A and 18B, this optical information recording medium 130 is provided with a recording layer 131 on a substrate 132 and functions as a photopolymer medium as a whole.

  The substrate 132 is a glass substrate like the substrates 102 and 103 in the first embodiment, and transmits light at a high rate. The substrate 132 has a square plate shape or a rectangular plate shape having a length dx in the x direction and a length dy in the y direction of about 30 to 80 [mm], and a thickness t32 of about 0.6 [mm]. It is configured.

  In the manufacturing stage of the recording layer 131, a liquid material M2 described later is developed on the substrate 132, and is irradiated from the initialization light source 81 by the initialization device 80 (FIG. 11) similar to that of the second embodiment. It is initialized by the initialization light L31.

Specifically, in the recording layer 131, Irg-784, which is an organometallic compound having a weight ratio of 1% as an organometallic compound, is mixed and defoamed in a dark room (hereinafter referred to as this). Is further developed on the substrate 132 so that the thickness t31 is about 500 [μm], and then the initialization light L31 (wavelength 365 [nm]) is generated by the initialization light source 81 formed of a high-pressure mercury lamp. It is photocured by being irradiated with a power density of 300 [mW / cm ² ]) for 20 [sec].

  In this initialization process, the recording layer 131 undergoes a photoreaction as a whole, so that the resin is polymerized and / or crosslinked inside as in the initialization (pre-cure) process in the first embodiment. As a result, the refractive index of the recording layer 131 changes as a whole as compared with that before irradiation of the initialization light. Incidentally, the recording layer 131 is almost transparent in the photocured state, and transmits the irradiated light at a high rate.

  Thus, like the optical information recording medium 120 in the second embodiment, the optical information recording medium 130 is configured as a thin plate as a whole and substantially transmits light, and the recording layer is subjected to initialization processing. The resin inside 131 reacts with light, and a small amount of organometallic compound is contained in the recording layer 131.

(3-3) Recording and Reproduction of Information Next, recording of information on the optical information recording medium 130 and reproduction of information from the optical information recording medium 130 in the third embodiment will be described.

  When recording information on the optical information recording medium 130, the optical information recording / reproducing apparatus 30 collects the recording light beam L32c from the recording / reproducing light source 32 (FIG. 17) in the recording layer 131 as shown in FIG. 19A. Shine. In this case, the optical information recording / reproducing apparatus 1 controls the positions of the optical pickup 35 (FIG. 17) in the x direction, the y direction, and the z direction, thereby causing the recording light beam L32c (FIG. 19A) to be recorded on the recording layer 131. The target position (namely, the target position) is focused.

  Specifically, the optical information recording / reproducing apparatus 30 uses a position having a depth of 100 [μm] from the surface of the recording layer 131 as a target position, a laser having a wavelength of 402 [nm] and an optical power of 20 [mW] from the recording / reproducing light source 32. A recording light beam L32c made of light was emitted, condensed by an objective lens 33 with NA = 0.35, and irradiated to a target position with an irradiation time of 1 [sec].

  The optical information recording / reproducing apparatus 30 emits a reading light beam L32d having the same wavelength as the recording light beam L32c and an optical power of 3 [mW] from the recording / reproducing light source 32 when reproducing information. The light is condensed on the recording mark RM in the recording layer 131.

  At this time, the read light beam L32d is reflected by the recording mark RM to become a return light beam L33. The optical information recording / reproducing apparatus 30 detects the return light beam L33 by the light receiving element 15 through the objective lens 33, the beam splitter 12, and the like.

  As shown in FIG. 20 (A), the light receiving element 15 has a high luminance as in the first embodiment (FIG. 5 (A)) and the second embodiment (FIG. 13 (A)). The return light beam L33 could be detected.

  This is because, in the vicinity of the target position in the recording layer 131, as in the recording layer 121, a cavity is formed in a portion where the temperature is locally increased by condensing the recording light beam L 32 c, and the material of the recording layer 131 and this It is presumed that the reflectance is improved due to the difference in refractive index between the cavity and the cavity.

  Thus, in the vicinity of the target position in the recording layer 131, as in the second embodiment, a recording mark RM that is a cavity and has a locally higher reflectance than the surrounding area is formed, and information is recorded. Become. Incidentally, it was difficult to visually confirm the recording mark RM.

  On the other hand, a return light beam L33 having a very low luminance was detected from a portion where the recording mark RM was not recorded (that is, an unrecorded portion) as shown in FIG. That is, when the optical information recording / reproducing apparatus 30 reproduces information from the optical information recording medium 130 as in the first and second embodiments, the detection intensity of the return light beam L33 depends on the presence / absence of the recording mark RM. It turns out that it is very different.

  As described above, the optical information recording / reproducing apparatus 30 uses the optical information recording medium 130 to concentrate the recording light beam L32c on the recording layer 131 containing the organometallic compound and precured in advance to increase the temperature. Thus, information recording can be performed in which a recording mark RM is formed by forming a cavity in the vicinity of the target position. Further, the optical information recording / reproducing apparatus 30 can perform information reproduction by detecting the return light beam L33 having a high luminance by irradiating the recording mark RM with the reading light beam L32d.

(3-4) Comparison with Other Optical Information Recording Medium Next, for comparison with the optical information recording medium 130, the optical information recording / reproducing apparatus 30 records and reproduces information using the optical information recording medium 140. went. The optical information recording medium 140 is provided with a recording layer 141 on a substrate 132, and functions as a photopolymer as a whole.

The recording layer 141 is obtained by mixing and defoaming an ultraviolet curable resin (Sony Chemical 06A32X-5) in a dark room (hereinafter referred to as a liquid material M3), and a thickness t31 of about 500 [μm] on the substrate 132. Then, the light is cured by being irradiated with initialization light L31 (power density 300 [mW / cm ² ] at a wavelength of 365 [nm]) for 20 [sec] by an initialization light source 81 composed of a high-pressure mercury lamp. ing.

  This recording layer 141 contains a photopolymerization initiator that senses the wavelength of ultraviolet rays in an ultraviolet curable resin, and was quickly photocured under the above conditions. Note that the photopolymerization initiator contained in the recording layer 141 does not contain an organic metal compound or an inorganic metal compound.

  Next, the optical information recording / reproducing apparatus 30 used the optical information recording medium 140 to record and reproduce information similar to the case of the optical information recording medium 130 described above.

  That is, the optical information recording / reproducing apparatus 30 uses a laser beam having a wavelength of 402 [nm] and an optical power of 20 [mW] from the recording / reproducing light source 32 as a target position at a depth of 100 [μm] from the surface of the recording layer 141. The recording light beam L32c was emitted and condensed by the objective lens 33 with NA = 0.35, and the target position was irradiated with an irradiation time of 1 [sec].

  The optical information recording / reproducing apparatus 30 emits a reading light beam L32d having the same wavelength as the recording light beam L32c and an optical power of 3 [mW] from the recording / reproducing light source 32 when reproducing information. The light was condensed at a target position in the recording layer 141.

  However, in this case, as shown in FIG. 21A, the result of light reception by the light receiving element 15 is that a weak return light beam L33 is obtained from the target position. Further, as shown in FIG. 21B, a weak return light beam L33 is obtained from a location other than the target position, that is, a location other than the location where the recording light beam L32c is condensed.

  From this light reception result, it was found that an effective recording mark RM was not formed on the optical information recording medium 140.

  That is, when the optical information recording media 130 and 140 are compared, the formation of the recording mark RM is considered to be caused by the alteration of the resin containing the organic metal compound or the inorganic metal compound due to the heat of the recording light beam L32c. .

  Therefore, it can be said that the optical information recording medium 140 in which the recording layer 141 does not contain an organometallic compound or an inorganic metal compound cannot function effectively as an information recording medium for the optical information recording / reproducing apparatus 30.

(3-5) Operation and Effect In the above configuration, the optical information recording / reproducing apparatus 30 according to the third embodiment is applied to the recording layer 131 in which the organometallic compound in the optical information recording medium 130 is blended and photocured in advance. Thus, by condensing the recording light beam L32c emitted from the recording / reproducing light source 32 at the target position and increasing the temperature, a cavity is formed in the vicinity of the target position, the reflectance is increased, and the recording mark RM is formed.

  Further, the optical information recording / reproducing apparatus 30 condenses the reading light beam L32d having a relatively weak light intensity with respect to the target position in the recording layer 131 of the optical information recording medium 130, and the strong luminance reflected by the recording mark RM. The return light beam L33 is received.

  Accordingly, in the optical information recording medium 130, as in the optical information recording medium 120 in the second embodiment, the recording layer RM is formed in a state where the photoreaction has been completed in advance by the photo-curing of the recording layer 131. It can be performed.

  Further, like the optical information recording medium 120, the optical information recording medium 130 contains an organometallic compound in the resin constituting the recording layer 131, so that the reflectance of light is kept low in the part that has been initialized. At the same time, the recording light beam L32c is condensed and the temperature locally rises and changes in quality, and a recording mark RM having a high reflectance can be formed by forming a cavity.

  At this time, since the optical reaction in the recording layer 121 is completed in the optical information recording medium 120, there is no change in the thermal conductivity caused by the change in the ratio of the photoreaction or the occurrence of the photon mode. The temperature in the vicinity of the position can be reliably increased.

  As a result, the optical information recording medium 130 can set the temperature in the vicinity of the target position of the recording layer 131 to be equal to or higher than the boiling point of the resin constituting the recording layer 121, so that the recording mark RM can be reliably formed by generating a cavity. it can.

  Therefore, when the optical information recording medium 120 is irradiated with the reading light beam L22d from the optical information recording / reproducing apparatus 20 at the time of information reproduction, the optical information recording medium 120 is compared with the portion where the recording mark RM is not formed from the portion where the recording mark RM is formed. And an extremely strong return light beam L23 can be detected. In other words, the optical information recording medium 120 can generate a reproduction signal having an extremely high SNR by the optical information recording / reproducing apparatus 20 as in the optical information recording medium 100 in the first embodiment. It can be played back accurately and stably.

  In addition, when the comparative optical information recording medium 140 was used, an effective recording mark RM was not formed on the recording layer 141 containing no organic metal compound or inorganic metal compound. On the other hand, it has also been found that the temperature rise or thermal destruction caused by condensing the recording light beam L32c is definitely caused by the formation of the recording mark RM.

  According to the above configuration, the optical information recording medium 130 according to the third embodiment is configured to record the recording light beam L32c by the optical information recording / reproducing apparatus 30 on the recording layer 131 in which the organometallic compound is mixed and photocured in advance. Is condensed at the target position and heated to form a recording mark RM having a high reflectance by forming a cavity in the vicinity of the target position, and with a sufficient amount of light reflected by the recording mark RM. By detecting the return light beam L33, information represented by the presence or absence of the recording mark RM can be read stably.

(4) Fourth Embodiment (4-1) Configuration of Optical Information Recording / Reproducing Device In the fourth embodiment, the optical information recording / reproducing device 20 is used as in the second embodiment. Is omitted.

(4-2) Configuration of Optical Information Recording Medium On the other hand, in the fourth embodiment, an optical information recording medium 150 is used instead of the optical information recording medium 120. The optical information recording medium 150 functions as a photopolymer medium as a whole by sandwiching a spacer 124 between substrates 122 and 123 and forming a recording layer 151 in an internal space 124A provided in the spacer 124. Has been made.

  In the recording layer 151, the liquid material M4 described later is developed in the internal space 124A in a state where the spacer 124 is sandwiched between the substrates 122 and 123 in the manufacturing stage, and the initializing device 80 shown in FIG. It is initialized by the initialization light L51 emitted from the activating light source 81.

  In the recording layer 151, like the recording layer 121 in the second embodiment, a photoreactive resin containing an organic or inorganic metal compound is uniformly dispersed. When the recording layer 151 is irradiated with light in the stage before initialization, the photoreactive resin undergoes a photoreaction at the irradiated portion, resulting in an increase in molecular weight and hardening, and the refractive index changes accordingly. It has properties.

Specifically, the recording layer 151 includes 40:60 (weight ratio) of acrylic acid ester monomer (p-cumylphenol ethylene oxide-added acrylic acid ester) and urethane bifunctional acrylate oligomer as an inorganic metal compound, and a weight ratio of 1 to the monomer and oligomer. TiO ₂ / H ₂ PtCl ₆ (molar ratio 10: 1) having a particle size of 20 [nm] or less in the same weight ratio 1 [%] as [%] 1-hydroxy-1-cyclohexyl phenyl ketone (Irg-184). An initialization light source 81 composed of a high-pressure mercury lamp is mixed and degassed in the dark room (hereinafter referred to as the liquid material M4), developed in the internal space 124A of the spacer 124 and sandwiched between the substrates 122 and 123. initializing light L51 (power density 300 mW / cm ² at a wavelength of 365 [nm]) is 20 [sec] illuminated by It is photocured by.

  In this initialization process, the recording layer 151 undergoes a photoreaction as a whole, so that the resin is polymerized and / or crosslinked inside as in the initialization (pre-cure) process in the first embodiment. As a result, the refractive index of the recording layer 151 changes as a whole as compared with that before the irradiation of the initialization light. Incidentally, the recording layer 151 is almost transparent in the photocured state, and transmits the irradiated light at a high rate.

  As described above, the optical information recording medium 150 has a configuration that is partially similar to the optical information recording medium 120 in the second embodiment, and is configured as a thin plate as a whole and substantially transmits light. The resin in the recording layer 151 is photoreacted by the initialization process, and a small amount of inorganic metal compound is contained in the recording layer 151.

(4-3) Information Recording and Reproduction Next, information recording on the optical information recording medium 150 and information reproduction from the optical information recording medium 150 in the fourth embodiment will be described.

  Incidentally, the optical information recording medium 150, like the optical information recording medium 120 in the second embodiment, has already been subjected to the initialization process in the first embodiment by being photocured at the time of manufacture. Therefore, the initialization process does not need to be performed again.

  When the optical information recording / reproducing apparatus 20 records information on the optical information recording medium 150, as shown in FIG. 12A, the recording light beam L52c from the recording / reproducing light source 22 (FIG. 9) is recorded on the recording layer. 151 is condensed. In this case, the optical information recording / reproducing apparatus 1 controls the positions of the optical pickup 25 (FIG. 9) in the x direction, the y direction, and the z direction to thereby transmit the recording light beam L52c (FIG. 12A) to the recording layer 151. The target position (namely, the target position) is focused.

  Specifically, the optical information recording / reproducing apparatus 20 uses a position having a depth of 100 [μm] from the surface of the recording layer 151 as a target position, and a laser having a wavelength of 402 [nm] and an optical power of 20 [mW] from the recording / reproducing light source 22. A recording light beam L52c made of light was emitted, condensed by the objective lens 23 with NA = 0.35, and irradiated onto the target position with an irradiation time of 2 [sec].

  The optical information recording / reproducing apparatus 20 emits a reading light beam L52d having the same wavelength as the recording light beam L52c and an optical power of 600 [μW] from the recording / reproducing light source 22 when reproducing information. The light is condensed on the recording mark RM in the recording layer 151.

  At this time, the read light beam L52d is reflected by the recording mark RM to become a return light beam L53. The optical information recording / reproducing apparatus 20 detects the return light beam L53 by the light receiving element 15 through the objective lens 23, the beam splitter 12, and the like.

  As shown in FIG. 22 (A), the light receiving element 15 has a high luminance as in the first embodiment (FIG. 5 (A)) and the second embodiment (FIG. 13 (A)). The return light beam L53 could be detected.

  On the other hand, a return light beam L33 having a very low luminance was detected from a portion where the recording mark RM was not recorded (that is, an unrecorded portion) as shown in FIG. That is, when the optical information recording / reproducing apparatus 20 reproduces information from the optical information recording medium 150 as in the first to third embodiments, the detection intensity of the return light beam L53 depends on the presence or absence of the recording mark RM. It turns out that it is very different.

  As described above, the optical information recording / reproducing apparatus 20 uses the optical information recording medium 150 to concentrate the recording light beam L32c on the recording layer 151 in which the inorganic metal compound is blended and is photocured in advance to increase the temperature. Thus, as in the first to third embodiments, it is possible to perform information recording in which a recording mark RM is formed by forming a cavity in the vicinity of the target position. Further, the optical information recording / reproducing apparatus 20 can perform information reproduction by detecting the return light beam L53 having a strong luminance by irradiating the read light beam L52d to the recording mark RM of the optical information recording medium 150.

(4-4) Operation and Effect In the above configuration, the optical information recording / reproducing apparatus 20 according to the fourth embodiment is applied to the recording layer 151 in which the inorganic metal compound in the optical information recording medium 150 is blended and photocured in advance. Thus, the recording light beam L52c emitted from the recording / reproducing light source 22 is condensed at the target position and heated to form a cavity near the target position to increase the reflectance and form the recording mark RM.

  Further, the optical information recording / reproducing apparatus 20 condenses the reading light beam L52d having a relatively weak light intensity with respect to the recording mark RM in the recording layer 151, and returning the light beam having a high luminance reflected by the recording mark RM. L53 is received.

  Therefore, in the same manner as the optical information recording medium 120, the optical information recording medium 150 can form the recording mark RM in a state where the photoreaction has been completed in advance because the recording layer 151 is photocured in advance. When the recording light beam L52c is condensed at the target position of the recording layer 151, the inorganic metal compound is surely thermally destroyed, so that a cavity is formed to locally increase the light reflectance, that is, the recording mark An RM can be formed.

  For this reason, when the optical information recording / reproducing apparatus 20 irradiates the reading light beam L22d, the optical information recording medium 150 is extremely strong from the position where the recording mark RM is formed to the position where the recording mark RM is not formed. The return light beam L53 can be detected. In other words, in the optical information recording medium 150, as in the first to third embodiments, the optical information recording / reproducing apparatus 20 can generate a reproduction signal having an extremely high SNR, and the information can be stably stabilized. Can be reproduced automatically.

  According to the above configuration, the optical information recording medium 150 according to the fourth embodiment is similar to the second and third embodiments with respect to the recording layer 151 in which the inorganic metal compound is blended and previously photocured. The optical information recording / reproducing apparatus 20 collects the recording light beam L52c at the target position and raises the temperature, thereby forming a recording mark RM having a high reflectance by forming a cavity in the vicinity of the target position. By detecting the return light beam L53 having a sufficient amount of light reflected at the recording mark RM, information represented by the presence or absence of the recording mark RM can be read stably.

(5) Other Embodiments In the above-described embodiments, the recording layers 121, 131, and 151 of the optical information recording media 120, 130, and 150 are made of a radical polymerization compound containing organic metal, inorganic metal, or both, and light. Although the case where the photopolymerizable resin containing the polymerization initiator is used has been described, the present invention is not limited to this, and the recording layers 121, 131, and 151 may be made of other compounds.

  Incidentally, as a constituent material of the photopolymerization type resin constituting the recording layers 121, 131 and 151, a photopolymerizable compound is generally considered, but in addition to this, a binder polymer, an oligomer, and photopolymerization are performed. In addition, a sensitizing dye may be added if necessary.

  Examples of the photopolymerizable compound include monomers mainly used for radical polymerization reactions such as acrylic acid, acrylic acid ester, acrylic amide derivatives, styrene and vinyl naphthalene derivatives. Moreover, it can apply also to the compound which has an acrylic monomer in a urethane structure.

  Further, as the above-described monomer, a derivative in which a halogen atom is substituted for a hydrogen atom may be used.

  On the other hand, as a binder component added as necessary, ethylene glycol, glycerin and derivatives thereof and polyhydric alcohols, phthalate esters and derivatives thereof, naphthalene dicarboxylic acid esters and derivatives thereof, phosphate esters and derivatives thereof, Examples thereof include compounds that can be used as plasticizers, such as fatty acid diesters and derivatives thereof.

  In addition, as the photopolymerization initiator in the initiator system, (bis (η-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H) shown in the above-described embodiment is used. In addition to -pyrrol-1-yl) -phenyl) titanium (Ciba Specialty Chemicals Irg-784), 2,2-dimethoxy-1,2-diphenylethane-1-one and 2-benzyl-2-dimethylamino- Examples thereof include organic compounds used for radical polymerization such as 1- (4-morpholinophenyl) -butanone-1,1-hydroxycyclohexyl phenyl ketone, etc. The photopolymerization initiator used at this time is, for example, after recording information. A compound that is suitably decomposed by post-treatment is desirable.

  Furthermore, examples of the sensitizing dye include cyanine-based, coumarin-based, and quinoline-based dyes.

  Further, in the first embodiment described above, the case where the optical information recording medium 100 is irradiated with the initialization light L1 formed of parallel light in the initialization process (FIG. 3A) has been described. The invention is not limited to this. For example, the optical information recording medium 100 may be irradiated with the initialization light L1 made of diffused light or convergent light. The same applies to the initialization light source 81 in the second to fourth embodiments.

  Further, in the first embodiment described above, the initialization light L1 for performing the initialization process of the optical information recording medium 100, the recording light beam L2c for recording information on the optical information recording medium 100, and the Although the case where the readout light beam L2d for reproducing information from the optical information recording medium 100 is unified to have a wavelength of 532 [nm] has been described, the present invention is not limited to this, and for example, the recording light beam L2c and While the wavelength of the read light beam L2d may be unified, the wavelength of the initialization light L1 may be different from both, or the wavelengths of the initialization light L1, the recording light beam L2c, and the read light beam L2d may be different from each other.

  In this case, the initialization light L1 has a wavelength suitable for the sensitivity of the photochemical reaction in the photopolymerized photopolymer constituting the recording layer 101, and the recording light beam L2c has a temperature that increases due to thermal conduction of the substance. It is desirable that the reading light beam L2d has a wavelength or a wavelength that can be easily absorbed. At this time, the NA and the like of the objective lens 13 (FIG. 1) may be appropriately adjusted according to the wavelengths of the recording light beam L2c and the reading light beam L2d, and further, the recording light beam is used during information recording and reproduction. Two objective lenses optimized for L2c and readout light beam L2d may be switched and used.

  In addition, with respect to the photopolymerized photopolymer constituting the recording layer 101, its components and the like are set so that the best characteristics can be obtained in combination with the wavelengths of the initialization light L1, the recording light beam L2c, and the reading light beam L2d. What is necessary is just to adjust suitably.

  Furthermore, in the second to fourth embodiments, the wavelengths of the recording light beams L22c, L32c and L52c emitted from the recording / reproducing light sources 22 and 32 and the reading light beams L22d, L32d and L52d are set to 402 [nm]. In addition, other wavelengths may be used. In short, it is only necessary that the cavity can be appropriately formed by efficiently increasing the temperature in the vicinity of the target position in the recording layers 121, 131, and 151.

  Further, in the first embodiment described above, the case where the initialization light L1, the recording light beam L2c, and the reading light beam L2d are respectively irradiated from the surface on the substrate 102 side of the optical information recording medium 100 has been described. The present invention is not limited to this, and each light or light beam may be irradiated from either surface, for example, the initialization light L1 may be irradiated from the surface on the substrate 103 side. The same applies to the second to fourth embodiments.

  Further, in the above-described first embodiment, when the thickness t1 (FIG. 2) of the recording layer 101 is about 0.3 [mm], the interval between the recording marks RM in the mark recording layer is 3 [ [mu] m] and the interval between the mark recording layers is about 15 [[mu] m] and 17 layers are stacked. However, the present invention is not limited to this, and for example, the thickness t1 of the recording layer 101 is about 1.0. [Mm], the interval between the recording marks RM in the mark recording layer is set to 5 [μm], and the interval between the mark recording layers is set to about 20 [μm]. Each value may be appropriately adjusted according to the size of the recording mark RM formed in the recording layer 101, various optical characteristics of the photopolymerization type photopolymer, or the optical characteristics of the objective lens 13.

  Further, in the second to fourth embodiments described above, the case where one recording mark RM is formed in the recording layers 121, 131, and 151 has been described. However, the present invention is not limited to this, As in the first embodiment, by appropriately changing the target position in the xy plane, a mark recording layer in which the recording marks RM are arranged in a plane is formed, and the position of the target position in the z direction (that is, from the surface) The recording marks RM may be formed in multiple layers by changing the depth) in stages. In this case, the thicknesses t21 and t31 of the recording layers 121, 131, and 151 may be appropriately adjusted according to the number of layers to be formed.

  Furthermore, in the first embodiment described above, the optical information recording medium 100 is fixed to the table 4, and the optical pickup 5 is displaced in the x direction, the y direction, and the z direction, so that an arbitrary position in the recording layer 101 is obtained. However, the present invention is not limited to this. For example, the optical information recording medium 100 may be a CD (Compact Disc), a DVD (Digital Versatile Disc), or the like. The optical disc may be configured to be rotated and the optical pickup 5 may be displaced in the x and z directions to record and reproduce information. In this case, for example, tracking control or focus control may be performed by forming a groove or pit track on the boundary surface between the substrate 102 and the recording layer 101. The same applies to the second to fourth embodiments.

  Further, in the above-described embodiment, the recording layer 101 of the optical information recording medium 100 is a square plate or a rectangular plate having a side of about 30 to 80 [mm] and a thickness t1 of about 0.3 to 1.0 [mm]. Although the present invention is not limited to this, the present invention is not limited to this, and may have other arbitrary dimensions, or may have various shapes such as a rectangular parallelepiped shape and a disk shape having various dimensions. . In this case, the thickness t1 in the z direction is preferably determined in consideration of the transmittance of the recording light beam L2c and the reading light beam L2d. The same applies to the second to fourth embodiments.

  Accordingly, the shapes of the substrates 102 and 103 are not limited to a square plate shape or a rectangular plate shape, and may be various shapes according to the recording layer 101. The material of the substrates 102 and 103 is not limited to glass but may be polycarbonate, for example. In short, the initialization light L1, the recording light beam L2c, the read light beam L2d, and the return light beam L3 are transmitted with high transmittance. Just do it. Furthermore, the substrates 102 and 103 may be omitted from the optical information recording medium 100 when a desired strength can be obtained with the recording layer 101 alone. The same applies to the second to fourth embodiments.

  Further, in the above-described embodiment, the case where the optical information recording medium 120, 130, or 150 as the optical information recording medium is configured by the recording layer 121, 131, or 151 as the recording layer has been described. However, the optical information recording medium may be configured by a recording layer having other various configurations.

  The present invention can also be used in an optical disc apparatus that records or reproduces a large amount of information such as video content or audio content on a recording medium such as an optical disc.

It is a basic diagram which shows the structure of the optical information recording / reproducing apparatus by 1st Embodiment. It is a basic diagram which shows the structure of the optical information recording medium by 1st Embodiment. 1 is a schematic diagram for explaining initialization of an optical information recording medium, information recording, and reproduction according to a first embodiment. FIG. It is a basic diagram which shows the temperature distribution in the optical information recording medium at the time of condensing recording light. It is a basic diagram which shows the mode of reception of the return light by 1st Embodiment. It is an approximate line figure showing signal intensity distribution of return light. It is an approximate line figure showing signal intensity distribution (1) of return light in each layer. It is a basic diagram which shows signal intensity distribution (2) of the return light in each layer. It is a basic diagram which shows the structure of the optical information recording / reproducing apparatus by 2nd Embodiment. It is a basic diagram which shows the structure of the optical information recording medium by 2nd Embodiment. It is a basic diagram which shows the structure of an initialization apparatus. It is a basic diagram with which it uses for description of the recording and reproduction | regeneration of the information by 2nd Embodiment. It is a basic diagram which shows the mode of reception of the return light by 2nd Embodiment. It is a photograph which shows the cross-sectional SEM image of a recording mark. It is an approximate line figure showing signal intensity distribution (1) of return light in each layer by a 2nd embodiment. It is an approximate line figure showing signal intensity distribution (2) of return light in each layer by a 2nd embodiment. It is a basic diagram which shows the structure of the optical information recording / reproducing apparatus by 3rd Embodiment. It is a basic diagram which shows the structure of the optical information recording medium by 3rd Embodiment. It is a basic diagram with which it uses for description of the recording and reproduction | regeneration of the information by 3rd Embodiment. It is a basic diagram which shows the mode of reception of the return light by 3rd Embodiment. It is a basic diagram which shows the mode of reception of the return light from the optical information recording medium for a comparison. It is a basic diagram which shows the mode of reception of the return light by 4th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 20, 30 ... Optical information recording / reproducing apparatus, 2, 21, 31 ... Control part, 3, 81 ... Initialization light source, 5 ... Optical pick-up, 10, 22, 32 ... Recording / reproducing light source, 13 , 23, 33 ... objective lens, 15 ... light receiving element, 100, 120, 130, 140, 150 ... optical information recording medium, 101, 121, 131, 141, 151 ... recording layer, 102, 103, 122 , 123, 132... Substrate, 124... Spacer, L1, L21, L31, L51... Initializing light, L2c, L22c, L32c, L52c... Beam, L3, L23, L33, L53 ... Return light beam, RM ... Recording mark.

Claims (5)

It is made of a resin having photopolymerizability, photocrosslinkability, or both, and after the resin is cured by irradiation with a predetermined initialization light, the predetermined recording light is condensed during recording of information. A recording layer that forms a cavity as a recording mark by increasing the temperature in the vicinity of the focal point of the recording medium and reproduces the information based on the return light according to the irradiation of the predetermined reading light when reproducing the information. An optical information recording medium. The recording layer is
The optical information recording medium according to claim 1, wherein the resin contains an organic metal compound, an inorganic metal compound, or both. The recording layer is
When the recording light is collected at the time of recording the information, the cavity is formed by causing a photochemical reaction or both a photochemical reaction and a thermochemical reaction through the organometallic compound, the inorganic metal compound, or both. The optical information recording medium according to claim 2. The recording layer is
When the initialization light is used, the organometallic compound, the inorganic metal compound, or both are altered to produce a metal compound, and when the recording light is collected during recording of the information, a photochemical reaction is performed via the metal compound. The optical information recording medium according to claim 2, wherein the cavity is formed by causing both a photochemical reaction and a thermochemical reaction. The recording layer is
2. The optical information according to claim 1, wherein the condensing position of the recording light is changed in a three-dimensional direction and the information is recorded, so that the plurality of cavities are arranged in a three-dimensional direction. recoding media.