JP2003006919A - Optical recording medium and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lowering of the read accuracy of a reproduction-only region even in an optical recording medium having a plurality of information recording layers. SOLUTION: The read accuracy of a reproduction-only region 107 is enhanced by forming no thin film on an information recording layer which overlaps the region 107 or by making the phase state of a phase change recording film in an information recording layer which overlaps the reproduction-only region such a state that the transmittance of recording and reproducing light is highest in the case of a rewritable optical recording medium using a phase change recording film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layered optical recording medium having a region in which information about the medium is recorded and having a plurality of information recording layers, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the expansion of the amount of information required by information equipment and audiovisual equipment, ease of data access,
A disc-shaped optical recording medium, so-called an optical disc, which is excellent in accumulating large-capacity data and miniaturization of equipment, has been receiving attention. As optical disks, there are reproduction-only optical disks, write-once optical disks, phase-change optical disks as recording / reproducing optical disks, magneto-optical disks, and the like.
It is called D, MO, etc. and has been put to practical use for various purposes.

In general, these optical discs are provided with a lead-in area in the inner peripheral portion, a lead-out area in the outer peripheral portion, and a data area therebetween, and if the lead-in area is, for example, a DVD, a DVD standard type ( DVD-
ROM / DVD-RAM / DVD-R, etc.), disk size, disk structure (one or two layers), area code, burst cutting area descriptor, linear velocity condition for specifying exposure amount during recording, read power , Information about the medium such as peak power and bias power, and information indicating the end of the data area in the lead-out area are recorded. In the data area, contents such as video and music are recorded in the read-only medium, and user data is recorded in the rewritable medium. Normally, at the time of reproduction, first, information about the medium in the lead-in area is read out, and then information in the data area is read out.

Due to market demand, optical discs are required to have a large capacity, and an optical disc having a plurality of information recording layers has been devised. Also, in consideration of the troublesomeness at the time of reproduction, an optical disc for reproducing a plurality of layers from one side has been developed and put into practical use. A single-sided dual-layer DVD-ROM corresponds to this. A rewritable optical disc has also been devised.
A rewritable optical disc is manufactured by using a phase change recording film. The phase change recording film is a substance whose refractive index with respect to recording / reproducing light changes depending on its phase state. The phase state is changed by changing the cooling rate of the recording film depending on the irradiation time and intensity of the recording / reproducing light irradiation. In a rewritable optical disc using a phase change recording film, a phase change recording film is formed on a concave and convex guide groove, and marks of different phases are formed on the phase change recording film for recording and reproduction.

[0005]

However, when there are a plurality of information recording layers, interlayer interference occurs. Also, the amount of reflected light per layer is very small, which is one-hundredth of the number of layers. Further, in the case of a rewritable optical disc, the signal amplitude in the data area is larger when the depth of the concavo-convex pattern is shallower. Therefore, in general, the depth of the concavo-convex pattern is made shallow in order to secure the signal quality in the data area. . Therefore, the signal amplitude when reproducing the reproduction-only information of the unevenness formed in advance in the lead-in area becomes extremely small.

Therefore, in the case of an optical disc having a plurality of information recording layers, the reproduction signal quality and reading accuracy of the information in the read-only area formed in the lead-in area are extremely reduced, and the worst necessary information can be read. Disappear. Even in the case of an optical disc having a plurality of information recording layers, it is an object of the present invention to provide an optical recording medium in which the reading accuracy of information in a read-only area is improved, and to provide a manufacturing method for manufacturing the optical recording medium. Is the purpose.

[0007]

In order to achieve the above object, in the optical recording medium according to the present invention, a thin film is formed in the area of the other information recording layer which overlaps the read-only area in which information about the medium is recorded. The phase state of the non-existing or phase-change recording film in the thin film is characterized in that the transmittance of the recording / reproducing light is the highest.

Further, in the optical recording medium manufacturing method according to the present invention, a substrate having a concavo-convex pattern in which information about the medium is recorded and a plurality of substrates having a desired concavo-convex pattern are prepared, and a thin film is formed on each concavo-convex pattern. In the method of manufacturing an optical recording medium in which a film is formed and the substrates are bonded together, a thin film is not formed in a region of another information recording layer that overlaps information about the medium when bonded together, or the thin film is a phase change recording film. In the case where the phase change recording film is configured to include, the phase state of the phase change recording film is set to the phase state in which the transmittance of the recording / reproducing light is the highest.

Further, in the optical recording medium manufacturing method according to the present invention, a substrate having a concavo-convex pattern on which information about the medium is recorded is produced, a thin film is formed on the concavo-convex pattern of the substrate, and the desired thin film is formed on the thin film. In the method for manufacturing an optical recording medium in which at least one information recording layer including a concavo-convex pattern and a thin film is formed, no film is formed in a region of a plurality of information recording layers overlapping information on the medium, or the thin film is a phase change recording film. It is characterized in that the phase state of the phase change recording film is set to the phase state in which the transmittance of the recording / reproducing light is the highest.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a diagram showing a cross section of an optical recording medium according to a first embodiment of the present invention, and FIG. 2 is a diagram showing a substrate 101 in FIG. In particular, FIG. 1 shows a rewritable optical disc having two information recording layers.

The optical disc shown in FIG. 1 has a first substrate 101 having a concavo-convex pattern formed thereon, a first information recording layer 102 and a second information recording layer 10 formed of a phase change recording film on the first substrate.
3, a transparent layer 1 which is intermediate between the first information recording layer 102 and the second information recording layer 103 and is substantially transparent to the recording / reproducing light 106.
04 and a protective layer 105 on the second information recording layer.

The thickness of the protective layer 105 is such that when a reproducing head having a recording capacity of 20 GB or more and an NA of 0.8 or more is used, the aberration of the condensed recording / reproducing light is reduced and the tolerance to the tilt of the disc surface is increased. Therefore, the total thickness of the optical disc is about 0.1 mm.
Considering compatibility with D and DVD, it is set to about 1.2 mm. Therefore, the substrate thickness of the first substrate 101 is about 1.1 mm. The transparent layer 104 is the first information recording layer 1 at the time of recording / reproducing.
02 and the aberration of the recording / reproducing light in the second information recording layer 103 were set to about 30 μm.

The depth of the concavo-convex pattern in the first information recording layer 102 and the second information recording layer 103 is the wavelength of the recording / reproducing light 106 in consideration of the signal quality at the time of recording / reproducing in the recording / reproducing area and the amplitude of the tracking error signal. Is about λ and the refractive index of the substance through which the recording / reproducing light 106 propagates is n, then about λ /
12n.

The first information recording layer 102 is a reproduction-only area 10
7 and a recording / reproducing area 108, and the second information recording layer 103 is composed only of a recording / reproducing area 109. In the reproduction-only area 107, information about the medium, for example, information about recording / reproducing / erasing characteristics, information for decoding data, etc. is recorded, and is used at the time of recording or reproducing.

Recording is performed by recording / reproducing light 10 from the protective layer 105 side.
6 incident on the recording / reproducing area 10 of the first information recording layer 102.
8 or the recording / reproducing area 10 of the second information recording layer 103
The recording / reproducing light 106 is focused on 9 and a mark is formed by changing the phase state of the phase change recording film forming the information recording layer. Playback is performed in the recording / playback areas 108 and 109.
In Fig. 1, the intensity change of the recording / reproducing light 106 caused by the mark on the phase change recording film and in the read-only area 107 due to the uneven pattern recorded in advance is observed.

In the optical recording medium according to the present invention, the area of the second information recording layer 103 which overlaps the read-only area 107 of the first information recording layer 102 is free of a thin film composed of a phase change recording film or a reflective film, or Although there is a thin film such as a phase change recording film, the phase state of the phase change recording film is the phase state with the highest transmittance. That is, the structure is such that the recording / reproducing light 106 is not reflected by the second information recording layer 103. Therefore, there is no interlayer interference, and it becomes possible to read the information in the reproduction-only area 107 with high accuracy. In the case of the information recording layer formed of the phase change recording film, the reflectance of the read-only area 107 is in a phase state where the reflectance is high.

FIG. 2 is a view of the substrate 201 viewed from the incident direction of the recording / reproducing light 106. The reproduction-only area 202 has pits formed in a radius of 22.6 mm to 23 mm, the pit length is 0.36 μm, and the track pitch is 0.4 μm. In the recording / reproducing area 203, a guide groove is formed with a radius of 23 mm to 58 mm, and the track pitch is 0.32 u.
m. The holding hole 204 has a diameter of about 15 mm in consideration of compatibility with CDs and DVDs.

The evaluation system in the present invention is a reproducing head NA.
The pits in the reproduction-only area were reproduced at a laser power of 0.4 mW with a wavelength of the recording / reproducing light of λ405 nm. If the second information recording layer does not have a thin film, it can be reproduced with a value of 8.0% in the jitter value representing the quality of the signal by the degree of temporal fluctuation of the signal, and the information recording layer is composed of a phase change recording film, When the transmittance of the second information recording layer was the highest, the jitter value was 8.5%. Incidentally, the first information recording layer, the second information recording layer, which is a conventional configuration,
When both information recording layers had thin films, the jitter value was 13% and the signal quality was degraded.

The present invention can be practiced even with a card type optical recording medium or an optical recording medium having three or more information recording layers. Even if both the first information recording layer 102 and the second information recording layer 103 have the read-only areas on both the inner circumference and the outer circumference, this does not impair the essence of the present invention.

(Embodiment 2) FIG. 5 is a diagram showing a manufacturing process of an optical disk according to Embodiment 2 of the present invention.
First, a method for manufacturing the first substrate 301 and the second substrate 401 will be described.

FIG. 3 is a diagram showing a method of manufacturing the first substrate 301. A photoresist 303 is applied to the glass plate 302 (step (3a)), and the photoresist 303 on the glass plate 302 is exposed to light or the like (step (3b)).
Photoresist 303 made soluble in alkali by exposure
Is removed by melting with an alkaline solution to obtain a desired uneven pattern (step (3c)). After the developing step, Ni or the like is sputtered for a plating electrode and plating is performed to form a metal plate 304 (step (3d)). The metal plate 304 is peeled from the glass plate 302 (step (3e)), and the photoresist 303 attached to the peeled metal plate 304 is removed.
A stamper 305 serving as a mold for the first substrate 301 is obtained. The shape of the stamper 305 is transferred to a synthetic resin such as polycarbonate by a method such as injection molding using the manufactured stamper 305 (step (3f)) to obtain the first substrate 301. Since the first substrate 301 does not need to transmit recording / reproducing light, a base material made of a material such as glass or metal is used as the base material.
You may produce by P method etc.

Next, FIG. 4 shows a method of manufacturing the second substrate 401. As the stamper, a stamper manufactured by the same method as the method shown in the first substrate manufacturing step is used. Stamper 40
2 is coated with UV curable resin 403 (step (4a)),
Then, a thin film sheet 404 having a thickness of about 0.1 mm made of synthetic resin such as polycarbonate is attached (step (4b)). In order to make the ultraviolet curable resin 403 have a desired film thickness, the stamper 402 and the thin film sheet 404 are rotated to remove excess ultraviolet curable resin (step (4c)),
Ultraviolet rays 405 are irradiated to cure the ultraviolet curable resin 403 (step (4d)). The interface between the stamper 402 and the ultraviolet curable resin 403 is peeled off to obtain the second substrate 401 (step (4e)).

The first substrate 501 and the second substrate 50 produced
2 has a pattern in which unevenness is inverted for each stamper. The concavo-convex pattern is composed of spiral pits or grooves and is formed in a range of an inner peripheral diameter of about 22 mm to an outer peripheral diameter of about 59 mm (step (5a), step (5b)). A reproduction-only area in which information about the medium is recorded is formed on the first substrate 501.

Next, in the case of a rewritable optical disc, the first information recording layer 503 and the second information recording layer 504 are formed on the concavo-convex pattern formed on the first substrate 501 and the second substrate 502, respectively ( Step (5c), Step (5
d)). The information recording layer is composed of a rewritable phase change recording film sandwiched between dielectric films and a reflective film made of a metal thin film such as aluminum or a silver alloy. These dielectric film, phase change recording film, and reflective film are formed by the sputtering method. In the case of a read-only optical disc, only the reflective film is formed.

Here, the formation of the reflection film, the phase change recording film, and the dielectric film on the second information recording layer 504 on the second substrate 502 is a reproduction showing information about the medium recorded on the first information recording layer 503. It is performed except the area overlapping the dedicated area. That is, the overlapping region is masked and sputtering is performed so that the films do not adhere. Alternatively, in the case of a rewritable type optical disc using a phase change recording film, the phase state of the phase change recording film in the area overlapping the read-only area indicating information about the medium is the phase state having the highest transmittance (step (5
e), step (5f)). Initial crystallization is performed at this time.
The initial crystallization is generally an operation in which an amorphous state immediately after forming a phase change recording film is changed to a crystalline state so that the phase change recording film can be rewritten.

No thin film is formed in the area of the information recording layer that overlaps with the read-only area that indicates information about the medium, or a thin film including a phase change recording film is formed and the phase state of the phase change recording film is changed to recording / reproducing light. On the other hand, by making the transmittance the highest, there is no or less inter-layer interference received from other layers when reproducing information about the medium, and there is no or less attenuation of the light amount to the information about the medium, improving reading accuracy. To do.

Next, the first substrate 501 and the second substrate 502 are attached (step (5g)). An ultraviolet curable resin 507 is applied on the first information recording layer 503, and the second substrate 502 is laminated so that the second information recording layer 504 faces the first information recording layer 503. Excess UV curable resin 507 is removed, and the substrate is rotated to obtain a desired film thickness. The thickness is set in consideration of the influence between the information recording layers and the aberration of the recording / reproducing light. Finally, ultraviolet rays 508 are irradiated to cure the ultraviolet curable resin 507 (step (5h)) to obtain a completed disc.

When manufacturing an optical disc having three or more information recording layers, the n-th substrate and the n-th information recording layer are manufactured by the same method as that for manufacturing the second information recording layer 504. It is carried out by laminating on one information recording layer by a method similar to the step (5e).

Further, in the case of a rewritable type optical disk using a phase change recording film, even if the phase state of the phase change recording film of the portion which overlaps the read-only area after bonding is set to have the highest transmittance for the recording / reproducing light. Good. In this case, the initial crystallization of the phase change recording film of each information recording layer is similarly performed after bonding.

(Third Embodiment) FIG. 6 is a diagram showing an optical disk manufacturing process in a third embodiment of the present invention. The first substrate 601 is made of synthetic resin such as polycarbonate, glass, or metal, and is manufactured by injection molding, 2P method, or the like using a stamper manufactured by the same method as in Embodiment 2 (step (6a)). . First information recording layer 602
Is composed of a rewritable phase change recording film sandwiched between a reflective film made of a metal thin film such as aluminum and a dielectric film, and is formed by a sputtering method or the like (step (6
b)).

Next, a YAG laser 603 is focused on the first information recording layer 602 by a condenser lens 604 to perform initial crystallization of the phase change recording film of the first information recording layer 602 (step (6
c)).

Next, an ultraviolet curable resin 606 is applied on the first information recording layer 602, a stamper 605 is placed thereon (step (6d)), and the excessive ultraviolet curable resin 606 is removed to obtain a desired film thickness. The substrate 601 and the stamper 605 which are superposed in this manner are rotated. The ultraviolet curable resin 606 is irradiated with ultraviolet rays 607 to be cured (step (6e)), and the stamper 605 is separated from the ultraviolet curable resin 606 (step (6f)). The UV curable resin 606 has a stamper 605.
The uneven pattern on the top is transferred.

Next, a second information recording layer 608 is formed on the ultraviolet curable resin 606 (step (6g)). Like the first information recording layer 602, the second information recording layer 608 is composed of a rewritable phase change recording film sandwiched between dielectric films and a reflective film made of a metal thin film such as a silver alloy, and is formed by a sputtering method. To do. According to the present invention, the first information recording layer 602
The area of the second information recording layer which overlaps the area in which the information on the medium is recorded is sputtered so that any of the phase change recording film, the dielectric film and the reflective film is not attached. For example, a mask is attached so that sputtering is not performed only in a desired region. Or phase change recording film, dielectric film,
After attaching the reflective film, the phase state of the phase change recording film is set to the state having the highest transmittance (step (6h)). At this time, the initial crystallization of the second information recording layer 608 is also performed. Finally, a protective layer 609 is formed on the second information recording layer 608 to obtain a completed disc (step (6h)).

When manufacturing an optical disc having three or more information recording layers, the process is repeated by repeating the steps (6d) to (6h) a necessary number of times. At this time, as with the formation of the second information recording layer 608, the formation of the information recording layer is such that the region of the first information recording layer 602 which overlaps the read-only region in which the medium information is recorded is not covered with a film. Alternatively, a phase-change recording film may be formed, and the phase state of the area of the phase-change recording film that overlaps with the read-only area in which the medium information is recorded may have the highest transmittance for the recording / reproducing light.

Further, in the case of a rewritable type optical disc using a phase change recording film, even if the phase state of the phase change recording film in the portion which overlaps with the read-only area after bonding is made to have the highest transmittance for the recording / reproducing light. Good. In this case, the initial crystallization of the phase change recording film of each information recording layer is similarly performed after bonding.

[0036]

As is apparent from the above description, according to the optical recording medium and the optical recording medium manufacturing method of the present invention,
In an optical recording medium having a plurality of information recording layers, recording / reproducing light is incident from one side to record or reproduce on the plurality of information recording layers, and at least one information recording layer has information about the medium. In the information recording layer from the recording / reproducing light incident surface to the area where the information about the medium is recorded, there should be no thin film such as a reflection film, a phase change recording film, or a dielectric film in the area overlapping the information about the medium. This makes it possible to eliminate interlayer interference and improve the accuracy of reading information in the reproduction-only area.

Further, in the present invention, a phase change recording film is used for the information recording layer, and in the information recording layer from the recording / reproducing light incident surface to the region where information about the medium is recorded, an area overlapping the information about the medium. By setting the phase change recording film of (1) to have the highest transmittance, it is possible to reduce interlayer interference and improve the accuracy of reading information in the read-only area.

[Brief description of drawings]

FIG. 1 is a sectional view showing an optical recording medium according to a first embodiment.

FIG. 2 is a diagram showing a first substrate according to the first embodiment.

FIG. 3 is a diagram showing a first substrate manufacturing method according to the second embodiment.

FIG. 4 is a diagram showing a second substrate manufacturing method according to the second embodiment.

FIG. 5 is a diagram showing a method for laminating optical disks according to the second embodiment.

FIG. 6 is a diagram showing a method of stacking optical discs according to the third embodiment.

[Explanation of symbols]

101,201,301,501,601 First substrate 102, 503, 602 First information recording layer 103, 504, 608 Second information recording layer 104 Middle class 105,609 Protective layer 106 recording / reproducing light 107,202 Play-only area 108, 109, 203 recording / reproducing area 204 holding hole 302 glass board 303 photoresist 304 metal plate 305,402,605 stamper 401,502 Second substrate 403, 507, 606 UV curable resin 404 Thin film sheet 405, 508, 607 UV rays 505,603 YAG laser 506, 604 Condensing lens

Claims (13)

[Claims] 1. A light having a plurality of information recording layers composed of a desired concavo-convex pattern and a thin film on the concavo-convex pattern, and having a read-only area in which information about a medium is recorded in at least one information recording layer. An optical recording medium, wherein the thin film is absent in at least an area of the information recording layer on the recording / reproducing light incident surface side that overlaps with the reproduction-only area. 2. A plurality of information recording layers each composed of a desired concavo-convex pattern and a thin film including a phase change recording film on the concavo-convex pattern, and information on a medium is recorded in at least one information recording layer. In the optical recording medium having a read-only area, the phase change recording film in at least the area of the information recording layer on the side of the recording / playback light incident surface overlapping the read-only area has a phase with the highest transmittance of the read / write light. An optical recording medium characterized by being in a state. 3. The optical recording medium according to claim 2, wherein the phase change recording film in the reproduction-only area is in a phase state in which the reflectance of the recording / reproducing light is the highest. 4. A step of producing a main substrate having a concavo-convex pattern including a reproduction-only area in which information about a medium is recorded, and medium information management information recording for forming a thin film on the concavo-convex pattern of the main substrate. A layer forming step, a step of producing at least one substrate on which a desired concavo-convex pattern is formed, and the concavo-convex pattern of each substrate so that a thin film is not formed in a region of each substrate overlapping the reproduction-only region. Forming a thin film on the pattern to form an information recording layer; and recording the substrate having the information recording layer formed on the recording / reproducing light incident surface side of the main substrate having the medium information management information recording layer formed thereon. A method of manufacturing an optical recording medium, comprising a bonding step of bonding transparent layers that are substantially transparent to reproduction light. 5. A step of producing a main substrate on which a concavo-convex pattern including a read-only area in which information about a medium is recorded is formed, and a thin film including a phase change recording film is formed on the concavo-convex pattern of the main substrate. Medium information management information recording layer forming step, a step of producing at least one substrate on which a desired uneven pattern is formed, and information for forming a thin film including a phase change recording film on the uneven pattern of the substrate A recording layer forming step, a step of setting a phase state of the phase change recording film in an area of the information recording layer overlapping the read-only area to a phase state having the highest transmittance of recording / reproducing light, and the medium information management information recording A bonding step of bonding the substrate having the information recording layer formed on the recording / reproducing light incident surface side of the main substrate having the layer formed thereon with a transparent layer that is substantially transparent to the recording / reproducing light. And a method for manufacturing an optical recording medium. 6. The phase state of the phase change recording film in the read-only area after the medium information management information recording layer forming step and before the laminating step is set to a phase state having the highest reflectance of the recording / reproducing light. 6. The method according to claim 5, further comprising steps.
A method for manufacturing an optical recording medium as described above. 7. A step of producing a main substrate on which a concavo-convex pattern including a read-only area in which information about a medium is recorded is formed, and a thin film including a phase change recording film is formed on the concavo-convex pattern of the main substrate. Medium information management information recording layer forming step, a step of producing at least one substrate on which a desired uneven pattern is formed, and information for forming a thin film including a phase change recording film on the uneven pattern of the substrate Recording layer forming step, and the substrate having the information recording layer formed on at least the recording / reproducing light incident surface side of the main substrate having the medium information management information recording layer formed thereon is a transparent layer substantially transparent to the recording / reproducing light. And the phase state of the phase change recording film in at least the area of the information recording layer on the side of the recording / reproducing light incident surface that overlaps the reproduction-only area. And a step of bringing into a phase state having the highest transmittance. 8. A step of setting the phase state of the phase change recording film of the medium information management information recording layer in the read-only area to a phase state in which the reflectance of the recording / reproducing light is highest after the bonding step. The optical recording medium manufacturing method according to claim 7, wherein 9. A step of producing a main substrate on which a concavo-convex pattern including a reproduction-only area in which information about a medium is recorded is formed, and medium information management information recording for forming a thin film on the concavo-convex pattern of the main substrate. A layer forming step, and forming a concavo-convex pattern on the medium information management information recording layer with a transparent layer that is substantially transparent to recording / reproducing light, and not forming a thin film in a region overlapping with the reproduction-only region. The information recording layer forming step of forming a thin film on the concavo-convex pattern formed in 1. is performed at least once, and a protective layer forming step of forming a protective layer substantially transparent to the recording / reproducing light on the information recording layer. An optical recording medium manufacturing method, comprising: 10. A step of producing a main substrate on which a concavo-convex pattern including a reproduction-only area in which information about a medium is recorded is formed, and medium information management information recording for forming a thin film on the concavo-convex pattern of the main substrate. A layer forming step, forming a concavo-convex pattern on the medium information management information recording layer with a transparent layer substantially transparent to recording / reproducing light, and including a phase change recording film on the concavo-convex pattern formed by the transparent layer. Deposit a thin film,
On the information recording layer, an information recording layer forming phase optimization step is performed at least once so that the phase state of the phase change recording film in the area overlapping with the read-only area is the phase state having the highest transmittance of the recording / reproducing light. And a protective layer forming step of forming a protective layer substantially transparent to the recording / reproducing light. 11. A step of setting a phase state of the phase change recording film in the read-only area to a phase state having a highest reflectance of the recording / reproducing light after the medium information management information recording layer forming step. The optical recording medium manufacturing method according to claim 10. 12. A step of producing a main substrate having a concavo-convex pattern including a reproduction-only area in which information about a medium is recorded, and a medium information management information recording for forming a thin film on the concavo-convex pattern of the main substrate. A layer forming step, forming a concavo-convex pattern on the medium information management information recording layer with a transparent layer substantially transparent to recording / reproducing light, and including a phase change recording film on the concavo-convex pattern formed by the transparent layer. An information recording layer forming step of forming a thin film to form an information recording layer is performed at least once, and a protective layer forming step of forming a protective layer substantially transparent to the recording / reproducing light on the information recording layer, And a step of setting a phase state of the phase change recording film in an area overlapping with the read-only area to a phase state in which the transmittance of the recording / reproducing light is the highest. 13. The method according to claim 12, further comprising a step of changing a phase state of the phase change recording film in the read-only area to a phase state having a highest reflectance of the recording / reproducing light after the protective layer forming step. A method for manufacturing an optical recording medium as described above.