JP2003173574A - Optical recording medium and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture an optical disk having a light transmitting layer 2 formed on a disk substrate 1 by laminating the disk substrate 1 and a sheet and which is hardly damaged in the light transmitting layer 2, sufficiently responding to a higher NA of an objective lens, capable of increasing the capacity while having high reliability. <P>SOLUTION: The light transmitting layer 2 comprises a light transmitting sheet 2a having 70 to 85 m thickness, a hard coat layer 2c made of a UV-curing resin having 0.5 to 5 μm formed on one face of the light transmitting sheet 2a, and a pressure sensitive adhesive layer 2b having 15 to 30 μm thickness formed on the other face of the sheet 2a. The medium is manufactured by laminating the light transmitting layer 2 and the disk substrate 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium and a method for manufacturing the same, and more particularly, to an optical system in which a light transmitting layer on a disk substrate is composed of a light transmitting sheet and a transparent adhesive layer. It is suitable for application to a recording medium.

[0002]

2. Description of the Related Art In recent years, in the field of information recording, various researches and developments regarding optical information recording systems have been promoted at various places. This optical information recording method has an advantage that recording and / or reproduction can be performed in a non-contact manner and a recording density higher than that of the magnetic recording method by one digit or more can be achieved.

Further, this optical information recording system has an additional advantage that it can correspond to respective memory types such as a read-only type, a write-once type and a rewritable type. Therefore, it is considered to be applied to a wide range of applications from industrial use to consumer use as a method that can realize an inexpensive large-capacity file.

Among these, in particular, a digital audio disk (DAD), an optical video disk, and the like, which are optical disks compatible with a read-only memory type, are now in widespread use.

An optical disk such as a digital audio disk has a light-transmissive disk substrate on which a concavo-convex pattern such as pits or grooves for indicating information signals is formed, and a reflective film made of a metal thin film such as an aluminum (Al) film. In addition, a protective film for protecting the reflective film from moisture (H ₂ O) and oxygen (O ₂ ) in the atmosphere is provided.

At the time of reproducing the information signal on the optical disk, reproducing light such as laser light is emitted from the disk substrate toward the concavo-convex pattern, and information is obtained by the difference in reflectance between the incident light and the returning light due to the reproducing light. Detect the signal.

When manufacturing such an optical disk, first, a disk substrate having an uneven pattern is formed by an injection molding method. Next, a reflective film made of a metal thin film is formed on the optical disk substrate by the vacuum evaporation method.
Next, an ultraviolet curable resin is applied to the upper layer of this reflective film to form a protective film.

In recent years, in such an optical information recording system, higher recording density is required. In order to meet the demand for higher recording density, a technique for reducing the spot diameter of the reproduction light by increasing the numerical aperture (NA) of the objective lens used when the reproduction light of the optical pickup is irradiated. Was proposed.

That is, for example, the NA of the objective lens used for reproducing the conventional DAD is 0.45, while the D having a recording capacity 6 to 8 times that of the conventional DAD is used.
VD (Digital Versatile Dis)
In the optical video disk such as c), the spot diameter can be reduced by setting the NA of the objective lens used during reproduction to about 0.60.

As the NA of such an objective lens is increased, in order to transmit the emitted reproduction light,
It is necessary to make the disc substrate of the optical disc thinner. This is because the allowable amount of the angle (tilt angle) deviated from the vertical direction of the disc surface with respect to the optical axis of the optical pickup becomes smaller, and further, this tilt angle is influenced by aberration and birefringence due to the thickness of the disc substrate. This is because they are easily affected.

Therefore, the tilt angle is made as small as possible by thinning the disk substrate.
For example, in the above-mentioned DAD, the thickness of the substrate is 1.
It is about 2 mm. On the other hand, DAD 6-8
In an optical video disc such as a DVD having a double recording capacity, the substrate has a thickness of about 0.6 mm.

In consideration of future demands for higher recording density, it is necessary to further reduce the thickness of the substrate.
Therefore, an unevenness is formed on one main surface of the substrate to form an information signal portion, and a reflective film and a light transmission layer made of a thin film capable of transmitting light are sequentially laminated on the information signal portion. There is proposed an optical disc configured to reproduce an information signal by irradiating reproduction light from the optical disc.

In such an optical disc which reproduces the information signal by irradiating the reproducing light from the light transmitting layer side, it is necessary to reduce the thickness of the light transmitting layer to cope with the high NA of the objective lens. You can

However, if the light transmitting layer is thinned, it becomes difficult to form the light transmitting layer by an injection molding method using a thermoplastic resin, which is generally used for manufacturing an optical disk. That is, it is very difficult to adopt a conventional technique to form a light-transmitting layer of about 0.1 mm that maintains good transparency while keeping the birefringence small.

Therefore, a method of forming the light transmitting layer with an ultraviolet curable resin has been proposed. However, when the light transmission layer is formed of an ultraviolet curable resin, it is very difficult to make the light transmission layer have a uniform film thickness on the substrate surface. Therefore, it becomes difficult to stably reproduce the information signal.

[0016]

Further, by using a laminating apparatus made of an elastic body and pressing a disk-shaped light-transmissive sheet having a pressure-sensitive adhesive formed on one main surface in advance and a substrate, A method of attaching the light transmitting layer has been proposed.

In this method, the disc-shaped sheet having the pressure-sensitive adhesive layer formed on the light-transmitting sheet is brought into contact with the information signal section on the substrate having the information signal section formed thereon. A light transmission layer is formed by laminating as described above.

However, this method has a problem that the light transmitting layer is damaged or soiled during the process of forming the light transmitting layer or when the user uses it.

Therefore, an object of the present invention is to prevent an optical disc having a light transmitting layer formed on the disc substrate by laminating a disc substrate and a sheet, and the light transmitting layer is not easily scratched, and the objective lens has a high NA. It is an object of the present invention to provide an optical recording medium and a method for manufacturing the same, capable of manufacturing an optical disc that can sufficiently cope with the demand for high-capacity and can increase the capacity while having high reliability.

[0020]

An optical recording medium according to the present invention for achieving the above object comprises an information signal section capable of recording and / or reproducing an information signal on a substrate.
In an optical recording medium including a light transmitting layer configured to be capable of transmitting a laser beam used for recording and / or reproducing the information signal, the light transmitting layer is a light transmitting sheet,
A hard coat layer made of an ultraviolet curable resin formed on one surface of the light transmissive sheet; and an adhesive layer formed on the other surface of the light transmissive sheet, wherein the light transmissive layer and the substrate It is characterized by being bonded together with.

The hard coat layer has a thickness of 0.5 to
It is characterized in that it is within the range of 5 μm.

The thickness of the light transmissive sheet is 70 to 8
It is characterized in that it is within the range of 5 μm.

The thickness of the pressure-sensitive adhesive layer is 15 to 30 μm.
It is characterized by being within the range of.

The method of manufacturing the optical recording medium of the present invention is
An information signal unit configured to record and / or reproduce an information signal and a light transmission layer configured to transmit a laser beam used for recording and / or reproduction of the information signal are provided on a substrate. In the method for producing an optical recording medium, a hard coat layer made of an ultraviolet curable resin is formed on one surface of a light transmitting sheet, and an adhesive layer is formed on the other surface of the light transmitting sheet to form a light transmitting layer. Is manufactured, and the light-transmitting layer and the substrate are bonded together to manufacture.

The hard coat layer and the pressure-sensitive adhesive layer are formed at the same time, or after forming the hard coat layer, the pressure-sensitive adhesive layer is formed, or after forming the pressure-sensitive adhesive layer, the hard layer is formed. Although a method of forming a coat layer is possible, preferably, after forming a hard coat layer made of an ultraviolet curable resin on one surface of the light transmissive sheet, an adhesive agent is formed on the other surface of the light transmissive sheet. By forming a layer to form a light-transmitting layer, and adhering the light-transmitting layer to the substrate, it is possible to suppress the occurrence of coating unevenness of the hard coat layer.

The hard coat layer is formed by uniformly applying an ultraviolet curable resin on the light transmissive sheet by a gravure coat method, and then irradiating and curing the ultraviolet curable resin.

In the present invention, in order to minimize warpage and distortion in the optical disc manufactured, it is preferable that
The light transmissive sheet is made of the same material as the material used for the substrate. Further, the thickness of the light transmissive sheet is typically configured to be smaller than the thickness of the substrate, and specifically, selected from 30 μm or more and 150 μm or less.

In the present invention, the disc substrate is specifically made of a resin having a low water absorption property such as polycarbonate (PC) or cycloolefin polymer, and the sheet is preferably the same as the disc substrate. Composed of materials.

The material used for the substrate is, for example, a substrate made of metal such as aluminum (Al),
Glass substrate, or polyolefin, polyimide,
It is also possible to use a substrate made of a resin such as polyamide, polyphenylene sulfide, or polyethylene terephthalate (PET).

The light transmissive sheet is typically made of polycarbonate resin, but it may be made of other resin materials.

In the present invention, in order to prevent the light-transmitting sheet from being scratched, a hard coat layer is provided on the surface of the light-transmitting sheet opposite to the side where the adhesive layer (adhesive layer) is provided. It is formed. The hard coat layer is made of an acrylic or methacrylic ultraviolet curable resin and is formed in advance on one surface of the light transmissive sheet by using a coating device such as a gravure coater.

In the present invention, typically, the light transmitting sheet is used for recording / reproducing at least an information signal. GaN semiconductor laser (emission wavelength 400 nm
Band, blue emission), ZnSe based semiconductor laser (emission wavelength 5
00 nm band, green), or an AlGaInP-based semiconductor laser (emission wavelength of 635 to 680 nm, red) or the like, made of a non-magnetic material capable of transmitting laser light. Specifically, it is light transmissive such as polycarbonate. Made of a thermoplastic resin.

The present invention is preferably DVR (Digi
tal Video Recording system
m) or the like, which is applicable to an optical disc having a thin light transmission layer, and is configured to record and reproduce an information signal by using a semiconductor laser having an emission wavelength of about 650 nm, a so-called DVRred, and an emission wavelength. Can be applied to an optical disc such as a so-called DVR blue which is configured to record and reproduce an information signal by using a semiconductor laser having a wavelength of about 400 nm.

This DVR is preferably constructed so that an information signal can be recorded by using an objective lens whose NA is increased to about 0.85 by combining two lenses in series. Has a storage capacity of about 22 GB on one side. Further, the optical disc to which the present invention is preferably applied, such as the DVR, is preferably contained in the cartridge, but the application of the present invention is not necessarily limited to the one contained in the cartridge.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In all the drawings of the following embodiments, the same or corresponding parts are designated by the same reference numerals. FIG. 1 shows a disk substrate on which the light transmitting layer of the present invention is formed.

First, as shown in FIG. 1, a disk substrate 1 on which a light transmitting layer is formed is prepared. This disk substrate 1 has a center hole 1b at the center of the replica substrate 1a.
Is formed, and the information signal portion 1c is provided on the one main surface on which the unevenness is formed.

The replica substrate 1a is made by an injection molding method using a predetermined stamper. The replica substrate 1a has a thickness of, for example, 0.6 to 1.2 mm. The material of the replica substrate 1a is, for example, polycarbonate or cycloolefin polymer (for example,
A low water-absorbing resin such as Zeonex (registered trademark) is used.

As the replica substrate 1a, for example, a substrate made of a metal such as aluminum (Al), a glass substrate, or a substrate made of a resin such as polyolefin, polyimide, polyamide, polyphenylene sulfide, or polyethylene terephthalate can be used. Is.

Further, a recording film, a reflective film, etc. are formed on the concave and convex portion formed on one main surface of the replica substrate 1a, whereby the information signal portion 1c is formed. The information signal section 1c is composed of a reflective film, a film made of a magneto-optical material, a film made of a phase change material, an organic dye film, or the like.
Among these, as the material of the reflective film, for example, Al is used.

Specifically, the optical disk as the final product is read-only (ROM (Read Only Memory).
In the case of the optical disk of y)), the information signal section lc is composed of a single layer film or a laminated film having at least a reflective layer made of Al or the like. On the other hand, when the optical disc as the final product is a rewritable optical disc, the information signal section 1c is composed of a single layer film or a laminated film having at least a film made of a magneto-optical material or a film made of a phase change material, In the case of the write-once optical disc, for example, it is composed of a single layer film or a laminated film having at least a film made of an organic dye material.

Here, the disk substrate 1 according to this embodiment is specifically, as the replica substrate 1a, for example, a disc-shaped polycarbonate (P) having a thickness of 1.1 mm.
C) A substrate is used, and the diameter (outer diameter) of this PC substrate is, for example, 120 mm, and the opening diameter (inner diameter) of the center hole 1b is, for example, 15 mm.

The thickness of the information signal portion 1c is 1
A film thickness of 18n is formed on the reflective layer made of Al alloy of 00nm.
m of a first dielectric layer made of a mixture of ZnS and SiO 2, a phase change recording layer made of a GeSbTe alloy layer having a thickness of 24 nm, zinc sulfide (ZnS) having a thickness of 140 nm, and silicon oxide (SiO 2) Mixture (ZnS / SiO
A laminated film in which the second dielectric layer composed of 2) is sequentially laminated is used.

FIG. 2 shows a light transmitting layer used for forming the light transmitting layer according to this embodiment. In FIG. 2, the light transmitting layer 2 includes a light transmitting sheet 2a and a transparent adhesive layer 2b.
The hard coat layer 2c and a hard coat layer 2c are preliminarily laminated sheets, and have a structure formed by punching into a plane annular shape like the disc substrate 1.

Here, as an example of the size of the sheet composed of the light transmissive sheet 2a and the pressure-sensitive adhesive layer 2b, the diameter (outer diameter) is 120 mm which is equal to the outer shape of the substrate. A 23 mm hole is formed in the center of this sheet.

The pressure-sensitive adhesive layer 2b is made of a pressure-sensitive adhesive which produces an adhesive force when pressure is applied.
It is possible to use an acrylic, rubber-based, urethane-based, or silicone-based pressure-sensitive adhesive, and an acrylic-based pressure-sensitive adhesive was used here.

A sheet-like sample having a pressure-sensitive adhesive formed in advance on a release film is laminated on the light-transmissive sheet 2a so that the pressure-sensitive adhesive (2b) side contacts the light-transmissive sheet 2a. Thickness is 15 μm to 30 μm
Is preferred. When the film thickness of the adhesive layer 2b is smaller than 15 μm, the thickness accuracy is deteriorated, the adhesive is squeezed out from the outer peripheral edge portion of the light transmission layer 2 in the completed optical disc, and the dust around it is easily absorbed. .

The light-transmissive sheet 2a is made of, for example, a light-transmissive thermoplastic resin satisfying at least optical characteristics capable of transmitting ultraviolet rays. This thermoplastic resin is specifically, for example, polycarbonate (PC),
Alternatively, it is a methacrylic resin such as polymethylmethacrylate (polymethylmethacrylate). Here, polycarbonate was used. The thickness of the light-transmitting sheet 2a is determined in consideration of the pressure-sensitive adhesive layer thickness, and the thickness of the light-transmitting layer in DVR is 100 μm.
It is preferably 5 μm.

In order to prevent the light transmitting sheet 2a from being scratched, the light transmitting sheet is provided on the surface of the light transmitting sheet 2a opposite to the side where the adhesive layer (adhesive layer) is provided. A hard coat layer 2c that protects 2a is provided.
The hard coat 2c is preferably formed by directly coating and curing an acrylic or methacrylic UV curable resin on the light transmissive sheet 2a with a gravure coater.

The thickness is preferably 0.5 μm to 5 μm. When the film thickness of the hard coat layer 2c is thinner than 0.5 μm, the accuracy of the coating thickness deteriorates and uneven coating occurs, which adversely affects the servo signal when reproducing the optical disc.
On the other hand, when the thickness of the hard coat 2c is thicker than 5 μm, the hard coat layer 2c is used when the optical disc is used for a long time.
The warp generated by the reaction of the uncured portion of the becomes large. Here, an organic solvent-containing acrylic ultraviolet curable resin is applied onto the light-transmissive sheet 2a using a gravure coater so that the thickness is 1 μm, and 500 mJ / c.
It was formed by curing by irradiating with ultraviolet rays of m ² .

Next, the disk substrate 1 and the above-mentioned sheet (light transmitting layer 2) are bonded together by the method shown in FIG. That is, the disc substrate 1 is fixed so that the information recording surface faces upward, the light transmitting layer 2 is arranged thereon so that the adhesive layer 2b faces the substrate side, and the light transmitting layer 2 is made of an elastic roller. Three
Then, roll it in the direction of the arrow in the figure and press it to bond it to the substrate.

As a result, as shown in FIG. 4, an optical disc in which the disc substrate 1 and the light-transmitting sheet 2a are bonded together and the light-transmitting layer 2 is provided on the recording surface (information signal portion 1c) of the disc substrate 1 is obtained. Manufactured.

This disk is used as an example of the embodiment.

On the other hand, a flat annular sheet having two layers, that is, the light-transmitting sheet 2a and the pressure-sensitive adhesive layer 2b, on which the hard coat layer 2c is not formed, is formed in the same manner as in the embodiment, and this is used as a comparative example. . Then, an ABS resin, which is a protective protector material for the pickup lens, was directly struck on the disks of the embodiment and the comparative example, and a collision test for observing the scratched condition was conducted.

That is, for a disk rotating at a linear velocity of 6.0 m / s, AB of 50 g at a velocity of 0.5 m / s.
The S resin was made to collide 1000 times, and the scratches generated in the light transmission layer were evaluated by measuring the reflectance. The area of the ABS resin that collides with the disk is 5 mm × 5 mm.

Table 1 shows the degree of deterioration of reflectance, which is the ratio of the reflectance of the disk before the collision test and the reflectance difference before and after the collision test.

[0056]

[Table 1]

From Table 1, in the disk of the comparative example in which the hard coat 2c was not formed, the reflectance deterioration degree was 0.34.
On the other hand, in the disk of the embodiment in which the hard coat 2c is formed, the reflectance deterioration degree was 0.08.

When the degree of deterioration of reflectance is 0.1 or more, recording and reproduction have a significant adverse effect. Therefore, in the disk of the embodiment in which the hard coat 2c is formed,
It was found that the degree of deterioration of reflectance was 0.08 and that it had sufficient scratch-prevention performance.

From the above results, in the disc according to the present embodiment, when the light transmission layer is formed on the one main surface of the disc substrate on which the information signal portion is provided, both main surfaces of the light transmission sheet are hard-coated in advance. Layer and a pressure-sensitive adhesive layer are laminated and integrated into a three-layer disc-shaped sheet, the thickness of the hard coat layer is in the range of 0.5 to 5 μm, and the thickness of the light-transmitting sheet is It is in the range of 70 to 85 μm, and the thickness of the pressure-sensitive adhesive layer is 15 to 30 μm.
Within the range, it is possible to obtain an optical disc having good recording and reproducing characteristics.

Although one embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described one embodiment, and various modifications based on the technical idea of the present invention are possible. It is possible.

For example, as the device for adhering the sheet to the substrate, the roller-shaped elastic body is used in this embodiment, but the same effect can be obtained by using the pad-shaped elastic body. For example, the numerical values, materials, and configurations of the optical discs mentioned in the above-mentioned embodiment are merely examples,
If necessary, different numerical values, materials, and optical disk configurations may be used.

Further, in the above-described one embodiment, the present invention is applied to the optical disk having the light transmitting layer, but is applied to the optical hard disk adopting the magneto-optical recording / reproducing and the removable optical hard disk. It is also possible.

Further, in the above-mentioned one embodiment, the present invention is applied to the phase change type optical disk in which the information signal is recorded by utilizing the phase change, but the technique of the present invention is used. The present invention can be applied to other rewritable optical disks, write-once optical disks, or read-only optical disks within the scope of the technical idea.

After manufacturing the optical disk according to the above-mentioned one embodiment, the other main surface of the disk substrate 1 may be provided, if necessary.
That is, the light-transmissive sheet 2a side is bonded to the other main surface of the replica substrate 1a on the side where the light-transmissive sheet 2a is not provided, in the same manner as described above, with an adhesive agent interposed therebetween. It is also possible to further form a light transmitting layer on the other main surface of the disc substrate 1 by bonding the two layers together.

[0065]

(1) As described above, according to the inventions of claims 1 to 4, since the light transmitting layer is not easily scratched or soiled, an optical recording medium having good recording and reproducing characteristics can be obtained. Therefore, ensuring high reliability even in long-term use,
It is possible to obtain an optical recording medium having a small birefringence, good transparency, and a light transmitting layer having a uniform film thickness, which can cope with a higher NA of an objective lens used at the time of recording and / or reproducing. (2) Further, according to the invention of claim 2, since the thickness of the hard coat layer is within the range of 0.5 to 5 μm, uneven coating of the hard coat layer does not occur, and the hard coat layer has a long-term use. The warp generated by the reaction of the uncured portion does not increase. (3) Further, according to the invention of claim 3, since the thickness of the light-transmitting sheet is within the range of 70 to 85 μm, the thickness of the light-transmitting layer is thin, for example, DVR (D
digital Video Recording sy
It is suitable for manufacturing a system). (4) According to the invention of claim 4, since the thickness of the pressure-sensitive adhesive layer is within the range of 15 to 30 μm, the thickness accuracy is improved and the film thickness of the entire light transmission layer is made uniform, and the light transmission is achieved. It is possible to prevent the adhesive from sticking out from the peripheral edge portion of the layer and adsorbing the surrounding dust. (5) According to the fifth and sixth aspects of the invention, since the light transmitting layer is not easily scratched or soiled, it is possible to manufacture an optical recording medium having excellent recording and reproducing characteristics. Therefore, high reliability is ensured even in long-term use, and it is possible to cope with the high NA of the objective lens used during recording and / or reproduction.
It is possible to produce an optical recording medium having a small birefringence, good transparency, and a light transmitting layer having a uniform film thickness.

[Brief description of drawings]

FIG. 1 is a sectional view showing a disk substrate according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an exemplary embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an example of a manufacturing method according to an embodiment of the present invention.

FIG. 4 is a sectional view showing a completed optical disc according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Disk substrate, 1a ... Replica substrate, 1b ... Center hole, 1c ... Information signal part, 2 ... Light transmitting layer, 2a ... Light transmitting sheet, 2b ... Adhesive layer, 2c ... Hard coat layer, 3 ... Roller.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI theme code (reference) G11B 7/26 531 G11B 7/26 531 (72) Inventor Mitsuhiro Abe 6-7 Kitashinagawa, Shinagawa-ku, Tokyo No. 35 Sony Corporation (72) Inventor Takeshi Yamazaki 6-7 35 Kita-Shinagawa, Shinagawa-ku, Tokyo No. 35 Sony Corporation (72) Inventor Tomomi Gyomoto 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo No. F-term in Sony Corporation (reference) 5D029 LA02 LB01 LB07 LB13 LB17 5D121 AA04 EE21 EE23 EE27 EE28 FF01 GG02

Claims (6)

[Claims] 1. An information signal can be recorded on a substrate and / or
Alternatively, in an optical recording medium including an information signal portion configured to be reproducible and a light transmission layer configured to transmit a laser beam used for recording and / or reproduction of the information signal, the light transmission layer is A light-transmitting sheet, a hard coat layer made of an ultraviolet curable resin formed on one surface of the light-transmitting sheet, and an adhesive layer formed on the other surface of the light-transmitting sheet, An optical recording medium comprising the light transmitting layer and the substrate bonded together. 2. The thickness of the hard coat layer is 0.5 to 5
The optical recording medium according to claim 1, wherein the optical recording medium is in the range of μm. 3. The thickness of the light transmissive sheet is 70 to 85.
The optical recording medium according to claim 1, wherein the optical recording medium is in the range of μm. 4. The optical recording medium according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness in the range of 15 to 30 μm. 5. An information signal can be recorded on the substrate and / or
Alternatively, a method of manufacturing an optical recording medium, comprising an information signal section configured to be reproducible and a light transmission layer configured to transmit a laser beam used for recording and / or reproduction of the information signal, A hard coat layer made of an ultraviolet curable resin on one surface of the light-transmitting sheet, and a pressure-sensitive adhesive layer on the other surface of the light-transmitting sheet to prepare a light-transmitting layer, and the light-transmitting layer and the substrate. A method for manufacturing an optical recording medium, which comprises manufacturing the optical recording medium by laminating. 6. The hard coat layer is formed by uniformly applying an ultraviolet curable resin on the light transmissive sheet by a gravure coating method, and then irradiating and curing the ultraviolet curable resin. 5. The method for manufacturing the optical recording medium according to 5.