JP2001052374A - Optical recording medium, recording / reproducing apparatus for recording / reproducing information on / from optical recording medium, and recording / reproducing method - Google Patents

Abstract

(57) Abstract: A technique for stably recording and reproducing information on a plurality of recording surfaces that can be formed in one recording layer of an optical recording medium is provided. A disk has a base layer and a recording layer laminated thereon. The base layer 2 has a guide surface 5 and three reference surfaces 7a, 7b, 7c. The guide surface 5 has a track 6 having a high reflectance. The three reference surfaces 7a, 7b, and 7c are located on the inner peripheral side of the disk 1, and are respectively d, 2d, and 3 from the guide surface 5.
d. In the recording layer 3, for example,
Three recording surfaces 4a, 4b, 4c are formed. Recording surface 4
a, 4b, and 4c respectively correspond to the reference values obtained by disposing the recording / reproducing spot P1 on the guide surface 5 and the reference surfaces 7a, 7b, and 7c while maintaining the guide spot P2 on the guide surface 5. It is formed at the same height as the reference surfaces 7a, 7b, 7c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to recording and reproducing information on and from an optical recording medium, and more particularly to recording and reproducing information on an optical recording medium having a plurality of recording surfaces and guide portions.

[0002]

2. Description of the Related Art Magneto-optical disk drives, write-once disk drives, phase change disk drives, CD-ROs
2. Description of the Related Art In recording and reproducing information on optical recording media such as M, DVD, and optical cards, it has been conventionally proposed to form a plurality of recording surfaces in one recording layer and record and reproduce information on each of the recording surfaces. I have. As used herein, the term "recording / reproducing" means recording and / or reproducing information. That is, it means that either recording or reproduction of information is performed at a time.

Japanese Patent Application Laid-Open No. 4-301226 discloses an optical recording medium on which a plurality of recording surfaces can be formed, and a recording / reproducing apparatus for recording / reproducing information on / from such an optical recording medium.

The optical recording medium has a guide surface on which tracks are formed and a single recording layer having a thickness capable of forming a plurality of recording surfaces. Further, the recording / reproducing apparatus includes a recording / reproducing optical system for forming a recording / reproducing spot for recording / reproducing information on the recording surface, and a guiding optical system for forming a guide spot for following a track on the guide surface. Have.

The position of the recording / reproducing spot with respect to the guide spot in the thickness direction of the recording layer is controlled by an adjusting member that outputs a plurality of discrete signals corresponding to the position of the recording surface in the optical axis direction. Determined by the transformer.

[0006]

In such a recording / reproducing apparatus, since the recording surface itself does not have a reflective surface or a track serving as a guide in the optical axis direction or the tracking direction, the position of the recording / reproducing spot is determined by the position of the guide surface. It must be controlled relatively accurately with respect to the guide spots located on the track.

As described above, the position of the recording / reproducing spot in the thickness direction of the recording layer is determined by the optical axis direction translator controlled by the adjusting member that outputs a plurality of discrete signals. For this reason, due to temperature changes, changes over time, etc.
Multiple discrete signals output from the adjusting member fluctuate, the output sensitivity of the optical axis direction shifter changes, and the optical path length of the recording / reproducing optical system and the guide optical system relatively changes. In this case, the position of the recording / reproducing spot with respect to the guide spot in the optical axis direction deviates from a certain value.

For this reason, for example, if the above-described displacement of the recording / reproducing spot in the optical axis direction occurs during recording, the recording state changes, and a recording surface partially shifted in the optical axis direction is formed. When reproducing such a recording surface, even if focus control is performed at the focal point of the recording surface, a focus error or a tracking error becomes large in a displaced portion, and the reproduction cannot be performed correctly.

The present invention has been made to solve such a problem, and an object of the present invention is to stabilize a plurality of recording surfaces which can be formed in one recording layer of an optical recording medium. An object of the present invention is to provide a technique for recording and reproducing information. More specifically, an object of the present invention is to provide an optical recording medium, a recording / reproducing apparatus, and a recording / reproducing method for enabling such stable information recording / reproducing.

[0010]

SUMMARY OF THE INVENTION The present invention, on one side, is an optical recording medium on which a plurality of recording surfaces can be formed, comprising a base layer and a recording layer provided thereon.
The recording layer may have a plurality of recording surfaces formed therein, and the base layer may have a guide surface on which tracks are formed and a recording surface formed in the recording layer formed at a different height from the guide surface. At least one reference plane for providing a reference value of the interval.

According to another aspect of the present invention, there is provided a recording / reproducing apparatus for recording / reproducing information on / from the above-mentioned optical recording medium, comprising: a first optical system for forming a guide spot;
A second optical system for forming a recording / reproducing spot, means for holding the guide spot on the guide surface, means for changing the height of the recording / reproducing spot with respect to the guide spot, and positioning on the guide surface Means for obtaining the height of the reference surface with respect to the guide surface from the difference in height between the recording / reproducing spot and the recording / reproducing spot located on the reference surface, and obtaining a reference value for the distance between the recording surfaces based on this. Based on the obtained reference value, the recording / reproducing spot is arranged at a desired height that is an integral multiple of the reference value with respect to the guide spot, and the recording / reproducing is performed while the guide spot is held on the guide surface. Recording / reproduction is performed by using the spot.

According to still another aspect of the present invention, there is provided a method for recording / reproducing information on / from the above-mentioned optical recording medium, comprising: arranging a guide spot and a recording / reproducing spot on a guide surface; Arranging the reference surface with respect to the guide surface based on the change in the height of the recording / reproducing spot on the reference surface, and obtaining a reference value of the interval between the recording surfaces based on the obtained value. Placing the recording / reproducing spot at a desired height of an integral multiple of the reference value from the guide surface based on the reference value, and performing recording / reproducing with the recording / reproducing spot while holding the guide spot on the guide surface. Performing the steps.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] As shown in FIG.
Light emitted from the recording / reproduction LD 11 is collimated by the collimating lens 12 with linearly polarized light perpendicular to the paper surface. The collimating lens 12 is appropriately moved along the optical axis by the support driving means 13, and the position in the optical axis direction is detected by the sensor 14. The support driving means 13 includes:
For example, it is composed of two parallel springs that support the collimating lens 12 so as to be movable in the optical axis direction, and a driving device that includes a coil and a magnet.

The light collimated by the collimator lens 12 is incident on a beam splitter (half mirror) 15, a part of which is transmitted therethrough, and the rest is reflected thereby. The light transmitted through the beam splitter 15 is condensed by the condenser lens 16 and enters the monitor PD 17. This monitor PD17 is used for measuring the amount of light emitted from the LD11.

The light reflected by the beam splitter 15 is reflected by the PBS 18 and travels to the mirror 19. Subsequently, as shown in FIG. 2, the light is reflected by the mirror 19, condensed by the objective lens 20, and
Is formed in the recording layer 3.

The reflected light from the spot P1 travels backward in the optical path at the time of incidence and reaches the beam splitter 15, and as shown in FIG. 1, the light transmitted therethrough is changed by a toric lens (convex lens + cylindrical lens) 21. The light is changed to convergent light having astigmatism and is incident on the PD 22. PD
Reference numeral 22 has a four-divided light receiving surface and is used for detecting a focus error signal and a recording / reproducing signal for the recording / reproducing spot P1 based on the astigmatism method.

On the other hand, as shown in FIG. 2, light emitted from the guide LD 30 is linearly polarized light parallel to the paper surface, passes through the hologram 31, is collimated by the collimating lens 32, and passes through the PBS 18. The light is reflected by the reflection mirror 19 and condensed by the objective lens 20 to form a spot P2 on the guide surface 5 of the disk 1.

The optical axis 33 of the guide optical system has an inclination θ with respect to the optical axis 34 of the recording / reproducing optical system.
Therefore, the guide spot P2 is formed at a position apart from the recording / reproducing spot P1 by a predetermined distance a in the tracking direction (perpendicular to the recording track). As the distance a, a value of 5 μm to 100 μm is selected.

The reflected light from the spot P2 is diffracted by the hologram 31 while traveling backward in the optical path at the time of incidence as shown in FIG. The ± first-order lights are respectively incident on PDs 35a and 35b having light receiving surfaces divided into six. ±
The primary lights are both convergent lights, and one focus is located in front of the PD 35a and the other focus is located in the back of the PD 35b. The PDs 35a and 35b are used for detecting a focus error signal by a so-called beam size method and detecting a tracking error signal and a reproduction signal (track number) by a push-pull method for the guide focus P2.

As shown in FIG. 2, the recording / reproducing apparatus has a supporting and driving means 40 for moving the objective lens 20, and the objective lens 20 is moved by the supporting and driving means 40 in the focusing direction and the tracking direction. It is appropriately moved in two directions.

As can be understood from the above description, the light from the recording / reproducing LD 11 and the light from the guiding LD 30 are orthogonal to each other in polarization direction and are synthesized and separated by the PBS 18, so that they enter the PD 22. The light from the LD 30 and the light from the LD 11 incident on the PDs 35a and 35b are both very small.

Since the optical axis 33 of the guide optical system is inclined with respect to the optical axis 34 of the recording / reproducing optical system, L
The light from D11 and the light from LD 30 are separated in the direction perpendicular to the plane of the paper of FIG. 1, and the light from LD 11 is divided into PDs 35a and 35a.
The light from the LD 30 does not enter the light receiving surface of the PD 22. As a result, a good signal with less crosstalk between PDs and noise is obtained.

As shown in FIG. 3, the disc 1 has a base layer 2 and a recording layer 3 laminated thereon. The base layer 2 has a guide surface 5 and three reference surfaces 7a,
7b and 7c. The guide surface 5 has a track 6 having a high reflectance.

The three reference surfaces 7a, 7b, 7c are located on the inner peripheral side of the disk 1 and each have a distance d from the guide surface 5.
It is located at. That is, the reference surfaces 7a, 7b, 7c are located at the heights d, 2d, 3d from the guide surface 5, respectively. The interval d is preferably 2 to 50 μm, and more preferably 5 to 15 μm.

At least one recording surface is formed in the recording layer 3 at a distance from the guide surface 5. For example, three recording surfaces 4a, 4b, 4c are formed at the same height as the reference surfaces 7a, 7b, 7c, respectively.

Hereinafter, the recording / reproducing operation for the recording surface 4a will be described. First, according to the focus error signal obtained based on the PDs 35a and 35b, the support driving means 4
The objective lens 20 is moved by 0, and the spot P2 is arranged on the track 6 on the guide surface 5. Subsequently, the collimating lens 12 is moved by the support driving means 13 according to the focus error signal obtained based on the PD 22, and the spot P 1 is arranged on the guide surface 5.

Next, the track number of the track 6 where the spot P2 is located is read based on the outputs of the PDs 35a and 35b, and the objective lens 20 is moved inward according to the read track number. The optical axis of the optical system for recording and reproduction is
a, and at a position where the spot P2 of the guide optical system captures the track 6.

Subsequently, the collimating lens 12 is moved so that the focus error signal obtained based on the PD 22 becomes 0, and the recording / reproducing spot P1 is moved to the reference surface 7a.
To place. Thereafter, the collimating lens 1 is driven by the support driving means 13 so that the output of the sensor 14 is kept constant.
2 is controlled. With this control, the position of the spot P2 in the focus direction with respect to the spot P1 is kept constant.

The position of the collimating lens 12 may be controlled so that the driving current flowing through the coil of the support driving means 13 is kept constant. However, such control is more difficult than the control based on the sensor 14. It is easily affected by vibration and the like, and the position accuracy of the spot P2 in the focus direction with respect to the spot P1 is low.

Thereafter, the objective lens 20 is moved in the tracking direction, and the spot P2 is arranged on a desired track 6. In this manner, by controlling the position of the guide optical system spot P2 in the tracking direction with reference to the track 6 of the guide surface 5, the position of the recording / reproducing optical system spot P1 is indirectly controlled in the tracking direction. Is done.

The position of the objective lens 20 is controlled in the focus direction in accordance with a focus error signal obtained based on the PDs 35a and 35b, whereby the focus of the spot P2 on the track 6 of the guide surface 5 is maintained. In other words, the guide spot P2 is always maintained on the guide surface 5.

As described above, since the position of the collimating lens 12 is controlled so as to keep the output of the sensor 14 constant, the position of the spot P2 in the focus direction with respect to the spot P1 is kept constant, that is, the interval d. Therefore,
The spot P2 is always located on a plane separated from the guide surface 5 by a fixed distance d.

This means that at the time of recording, the recording surface 4a is formed exactly at the distance d from the guide surface 5, and at the time of reproduction, the spot P1 always has the correct recording surface 4a.
Means located above. Therefore, stable recording and reproduction can be performed.

Recording and reproduction on the recording surface 4b can be performed in the same manner. That is, first, the optical axis 34 of the recording / reproducing optical system is used.
Crosses the reference surface 7b, and at a position where the spot P2 of the optical system for guiding captures the track 6 on the guide surface 5,
The objective lens 20 is arranged. Subsequently, after adjusting the spot P1 to the reference surface 7b, the position of the spot P1 in the focus direction with respect to the spot P2 is held by keeping the output of the sensor 14 constant. After that, the guide surface 5
The spot P2 is controlled in the focus direction for the track 6 of FIG. As a result, the spot P1 is maintained on the recording surface 4b separated from the guide surface 5 by a certain distance d. The same applies to recording and reproduction on the recording surface 4c.

As can be seen from the above description, LD1
Conventionally, various factors that cause the relative position of the spot P1 and the spot P2 in the focus direction to shift, such as a change in the wavelength of the LD 1 and the LD 30, a change in the drive current sensitivity of the support driving unit 13, and an offset of the sensor 14, are known. Also, the relative position between the spot P1 and the spot P2 can be accurately and stably held.

In the present embodiment, the number of recording surfaces is set to three, but any number of one or more may be used. Further, the method of error detection may be another method.

[Modification] A modification of the disk 1 will be described below. In the following description and the drawings related thereto, members equivalent to those described above are denoted by the same reference numerals,
Detailed description is omitted.

The disk 1 according to the first modification shown in FIG. 4A has only one reference surface 7. The height of the reference surface 7 with respect to the guide surface 5 is the recording surface 4a, 4b, 4c.
Is equal to the distance d.

First, both the spot P1 and the spot P2 are arranged on the guide surface 5. Subsequently, the spot P2 is arranged on the guide surface 5, and the spot P1 is arranged on the reference surface 7.
The output difference of the sensor 14 when the spot P1 is located on the guide surface 5 and when it is located on the reference surface 7 is stored.

For recording and reproduction on the recording surface 4a, the target value of the sensor 14 for controlling the collimating lens 12 is set to a value equal to the output of the sensor 14 when the spot P1 is located on the reference surface 7.

In recording and reproduction on the recording surface 4b, the target value of the sensor 14 for controlling the collimating lens 12 is set to a value obtained by adding the above-mentioned output difference to the target value in recording and reproduction on the recording surface 4a.

In recording and reproduction on the recording surface 4c, the target value of the sensor 14 for controlling the collimating lens 12 is set to a value obtained by adding twice the output difference to the target value in recording and reproduction on the recording surface 4a.

In this modification, since there is only one reference plane,
Since the maximum step between the guide surface 5 and the reference surface is small, the formation of the reference surface is easy.

The disk 1 according to the second modification shown in FIG. 4B has only one reference surface 7. The height of the reference surface 7 with respect to the guide surface 5 is the recording surface 4a, 4b, 4c.
Is equal to half of the interval d, that is, d / 2.

First, both the spot P1 and the spot P2 are arranged on the guide surface 5. Subsequently, the spot P2 is arranged on the guide surface 5, and the spot P1 is arranged on the reference surface 7.
The output difference of the sensor 14 when the spot P1 is located on the guide surface 5 and when it is located on the reference surface 7 is stored.

For recording / reproducing on the recording surface 4a, the target value of the sensor 14 for controlling the collimating lens 12 is set to twice the output difference.

In recording and reproduction on the recording surface 4b, the target value of the sensor 14 for controlling the collimating lens 12 is set to a value obtained by adding twice the output difference to the target value in recording and reproduction on the recording surface 4a.

In recording and reproduction on the recording surface 4c, the target value of the sensor 14 for controlling the collimating lens 12 is set to a value obtained by adding four times the output difference to the target value in recording and reproduction on the recording surface 4a.

In this modification, there is only one reference plane,
Since the maximum step between the guide surface 5 and the reference surface is smaller than in the first modification, the formation of the reference surface is easier.

The disk 1 according to the third modification shown in FIG. 4C has only one reference surface 7. The height of the reference surface 7 with respect to the guide surface 5 is the recording surface 4a, 4b, 4c.
Is equal to three times the distance d, ie, 3d.

First, both the spot P1 and the spot P2 are arranged on the guide surface 5. Subsequently, the spot P2 is arranged on the guide surface 5, and the spot P1 is arranged on the reference surface 7.
The output difference of the sensor 14 when the spot P1 is located on the guide surface 5 and when it is located on the reference surface 7 is stored.

For recording and reproduction on the recording surface 4a, the target value of the sensor 14 for controlling the collimating lens 12 is set to one third of the output difference.

In recording and reproduction on the recording surface 4b, the target value of the sensor 14 for controlling the collimating lens 12 is set to two thirds of the output difference.

In recording and reproduction on the recording surface 4c, the target value of the sensor 14 for controlling the collimating lens 12 is set to a value equal to the output difference.

The disk 1 according to the fourth modification shown in FIG. 4D has two reference surfaces 7a and 7b. The height of the reference surface 7a with respect to the guide surface 5 is d0, and the height of the reference surface 7b with respect to the reference surface 7a is the recording surfaces 4a, 4
It is twice the interval d between b and 4c, that is, equal to 2d. d0> d, for example, d0 = 50 μm and d = 10 μm.

First, both the spot P1 and the spot P2 are arranged on the guide surface 5. Subsequently, the spot P2 is arranged on the guide surface 5, and the spot P1 is arranged on the reference surface 7a.

In recording / reproducing on the recording surface 4a, the target value of the sensor 14 for controlling the collimating lens 12 is set to the value of the sensor 14 when the spot P1 is located on the reference surface 7a.
Set to a value equal to the output of.

In recording / reproducing the recording surfaces 4b and 4c, the spot P1 is further arranged on the reference surface 7b, and the output difference of the sensor 14 when the spot P1 is located on the reference surface 7a and when the spot P1 is located on the reference surface 7b. Is stored.

In recording and reproduction on the recording surface 4b, the target value of the sensor 14 for controlling the collimating lens 12 is set to a value obtained by adding half of the output difference to the target value in recording and reproduction on the recording surface 4a.

In recording and reproduction on the recording surface 4c, the target value of the sensor 14 for controlling the collimating lens 12 is set to a value obtained by adding the output difference to the target value in recording and reproduction on the recording surface 4a.

The disk 1 according to the fifth modification shown in FIG. 5A has a reference surface 7a located on the inner peripheral side and a reference surface 7b located on the outer peripheral side. The heights of the reference surface 7a and the reference surface 7b with respect to the guide surface 5 are both the recording surfaces 4a and 4b.
b, 4c equal to the distance d.

Recording and reproduction on the disk 1 are performed in exactly the same manner as in the first modification.

In the present modified example, since the reference surface is provided at two places on the inner peripheral side and the outer peripheral side of the disk 1, it is possible to access the reference plane in a short time.

The disk 1 according to the sixth modification shown in FIGS. 5B and 5C has three reference surfaces 7a, 7b, 7c arranged along the track direction on the inner peripheral side. Have.
The height of the reference surfaces 7a, 7b, 7c with respect to the guide surface 5 is d, respectively, where d is the distance between the recording surfaces 4a, 4b, 4c.
2d and 3d.

Recording and reproduction on the recording surfaces 4a, 4b and 4c are performed in the same manner as in the above-described embodiment.

A more preferable disk has a similar reference surface 7.
a, 7b, 7c are also provided on the outer peripheral side of the disk 1. This enables quick access, as described above.

In this modification, three reference surfaces 7a, 7b, 7
c, but since they do not occupy a large area in the tracking direction, a wide recording track can be formed. In addition, the distance between the spot P1 and the spot P2 can be reduced.

[Second Embodiment] Hereinafter, a recording and reproducing apparatus according to a second embodiment will be described. The configuration of the recording / reproducing apparatus of the present embodiment is almost the same as that of the first embodiment, and the functions of some optical elements are only slightly different.

Specifically, in this embodiment, in FIG. 1, the support driving means 13 can move the collimating lens 12 not only in the direction of the optical axis but also in the direction orthogonal thereto.
In response, the sensor 14 can detect the position of the collimating lens 12 in the optical axis direction and the direction orthogonal thereto.

A hologram is used instead of the toric lens 21 to detect a focus error by a beam size method and a tracking error by a push-pull method.

As described above, the present embodiment differs from the first embodiment only in the function of the supporting / driving means for the collimating lens and the sensor. Therefore, the configuration of the recording / reproducing apparatus of the present embodiment is different. Are not shown.

As shown in FIG. 6, the disc 1 has a base layer 2 and a recording layer 3, and the recording layer 3 has seven recording surfaces 4a to 4g spaced at a constant and equal interval d. Can be formed. The base layer 2 includes a guide surface 5, a reference surface 7, and a surface 8.
have. The guide surface 5 has two tracks 6a and 6b arranged at a predetermined interval e. The reference surface 7 has a height of 3d with respect to the guide surface 5.

The surface 8 is located in a region where the recording surfaces 4a to 4g are formed, and has a high reflectance like the guide surface 5. The recording surface 4g is formed at the same height as the reference surface 7, and the recording surface 4a is formed at a position relatively distant from the surface 8 so that the light reflected from the surface 8 becomes sufficiently small.

First, both the recording / reproducing spot P1 and the guide spot P2 are fixed to one track 6a of the guide surface 5, and the output of the sensor 14 in the focus direction and the track direction is reset.

Next, the collimator lens 12 is moved in the track direction, and only the spot P1 is positioned on the track 6b (denoted by P1 '). Based on the output of the sensor 14 at this position, the spot P1 and the spot P2
Is obtained in the tracking direction, that is, the track interval e.

Subsequently, while the spot P2 is fixed to the track 6a on the guide surface 5, the collimating lens 12 is moved in the track direction and the optical axis direction to position the spot P1 on the reference surface 7 (indicated by P1 ''). ). Based on the output of the sensor 14 at this position, a reference value d in the focus direction of the spot P1 and the spot P2 is obtained.

In the present embodiment, the recording / reproducing spot P1 is kept at a predetermined distance from the spot P2 in two directions of the focus direction and the tracking direction while the guide spot P2 is held on the track 6a of the guide surface 5. It is performed by moving each time.

Specifically, the spot P1 is moved forward or backward from the guide surface 5 by a desired integral multiple of the reference value d in the focus direction, and is shifted outward from the track 6a by the reference value e in the track direction. Is moved by a desired integer multiple of the position of the spot P2. Recording and reproduction are performed while maintaining the relative position to the spot P2.

Although several embodiments have been described in detail with reference to the drawings, the present invention is not limited to the above-described embodiments, but may be performed within the scope of the invention. Including all implementations.

This specification includes the inventions listed below.

1. An optical recording apparatus for optically recording and / or reproducing information on an optical recording medium having at least one recording section and a guide section, and irradiating the recording section with light to record and reproduce information. And / or a first light for reproducing and a second light for irradiating the guide portion with light.
A recording device that irradiates a light on a guide portion and controls a relative position of the first light with respect to the second light to position the first light on the recording portion; Has a first interval in a first direction with respect to the guide portion, the optical recording medium has a reference portion having a second interval, and irradiates the first portion with the first light, A recording and / or reproducing method for an optical recording / reproducing apparatus, wherein a reference signal at a first interval is obtained.

2. In the first mode, the first direction is a focus direction.

3. In Item 1, the reference portion is disposed on an inner peripheral side of the recording medium.

4. In the first mode, the reference portion is arranged on an outer peripheral side of the recording medium.

5. In the first mode, the first interval is:
The same as the second interval.

6. In item 1, there are at least two recording units.

7. In the sixth mode, the interval between two adjacent recording portions is the same as the second interval.

8. In the first item, there are a plurality of the reference portions.

9. In the first item, there are a plurality of the second intervals.

10. In the first mode, when the recording section is irradiated with the spot of the first light, the deviation of the spot of the first light from the recording section in the first direction is detected. Not performed by the first light.

11. In the first aspect, the reference units are provided in the same number as the number of the recording units.

12. In the first mode, the number of the reference portions is equal to the number of the recording portions.

13. In the sixth mode, the second interval has an interval between the recording section furthest from the guide section and the guide section.

14. An optical recording apparatus for optically recording and / or reproducing information on an optical recording medium having at least one recording section and a guide section, and irradiating the recording section with light to record and reproduce information. And / or a first light to regenerate,
A second light for irradiating the guide portion with light, irradiating the guide portion with the second light, and controlling a relative position of the first light with respect to the second light, thereby forming the second light. An optical recording and reproducing apparatus according to claim 1, wherein the recording medium includes a reference portion having a predetermined interval with respect to the relative position.

15. In the paragraph 14, a means for irradiating the reference portion with light is provided.

16. In an optical recording medium having at least one recording portion and a guide portion, the recording portion and the guide portion are separated from each other by a first distance in a first direction, and a second distance from the first direction. An optical recording medium, comprising:

[0098]

According to the present invention, the recording / reproducing spot is stably arranged at a constant height from the guide surface in accordance with the reference value obtained based on the reference surface, so that stable information recording / reproduction can be performed. Become so.

[Brief description of the drawings]

FIG. 1 shows an optical system of a recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 shows the optical system of the recording / reproducing apparatus of FIG. 1 viewed from another angle, in which the inclination of the optical axis of the guide optical system is exaggerated.

FIG. 3 is an enlarged view of a cross section of the optical disc shown in FIG. 2 and an objective lens.

4A is a first modified example of the optical disk, FIG. 4B is a second modified example of the optical disk, FIG. 4C is a third modified example of the optical disk,
(d) shows a fourth modification of the optical disk.

FIG. 5A shows a fifth modified example of the optical disk, and FIGS. 5B and 5C show a sixth modified example of the optical disk.

FIG. 6 shows a cross section of an optical disc in a second embodiment of the present invention.

[Explanation of symbols]

 1 Disc 2 Base layer 3 Recording layer 4a, 4b, 4c Recording surface 5 Guide surface 6 Track 7a, 7b, 7c Reference surface

Claims (3)

[Claims] An optical recording medium on which a plurality of recording surfaces can be formed, comprising a base layer and a recording layer provided thereon, wherein the recording layer has a plurality of recording surfaces. The base layer may include a guide surface on which tracks are formed, and at least one reference surface formed at a different height from the guide surface and providing a reference value for a distance between recording surfaces formed in the recording layer. An optical recording medium comprising: 2. A recording / reproducing apparatus for recording / reproducing information on / from the optical recording medium according to claim 1, wherein the first optical system forms a guide spot and the second optical system forms a recording / reproducing spot. Second optical system, means for holding the guide spot on the guide surface, means for changing the height of the recording / reproducing spot with respect to the guide spot, Means for obtaining the height of the reference surface with respect to the guide surface from the difference in the height of the positioned recording / reproducing spot, and obtaining a reference value of the interval between the recording surfaces based on the height. The recording / reproducing spot is arranged at a desired height which is an integral multiple of the reference value with respect to the guide spot based on the value, and the recording / reproducing is performed by the recording / reproducing spot while holding the guide spot on the guide surface. Record Recording and playback device. 3. A method for recording / reproducing information on / from an optical recording medium according to claim 1, wherein a step of arranging a guide spot and a recording / reproducing spot on a guide surface, and arranging the recording / reproducing spot on a reference surface. A step of obtaining the height of the reference surface with respect to the guide surface based on the change in the height of the recording / reproducing spot, and obtaining a reference value of the interval between the recording surfaces based on the obtained value. A step of arranging the recording / reproducing spot at a desired height that is an integral multiple of the reference value from the guide surface, and a step of performing recording / reproducing with the recording / reproducing spot while holding the guide spot on the guide surface. You have a recording and playback method.