JP2003242694A - Method for manufacturing optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical recording medium for suppressing thickness nonuniformity in the case of spin-coating of resin materials that form an intermediate layer, etc., and suppressing thickness nonuniformity in particular even when sputter flakes exist. <P>SOLUTION: A first substrate which is of an almost disk shape with a center hole at the center and has a recessed and projecting shape on one face is formed. A first optical recording layer is formed on the surface of the first substrate which has the recessed and projecting shape. Resin 21a to form an intermediate layer is supplied to the center part of an almost circular sheet- shaped second substrate 20 with no center hole at the center. Spin-coating is performed, the stamper 22 is pasted together to cure the resin, and the stamper 22 is peeled off to transfer a recessed and projecting shape. A second optical recording layer is formed on the obtained recessed and projecting shape formation surface, and a center hole is opened at the center of the second substrate. The first optical recording layer side of the first substrate and the second optical recording layer side of the second substrate are pasted together with a pasting layer. <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 a method for manufacturing an optical recording medium (hereinafter also referred to as an optical disk), and more particularly to a method for manufacturing an optical recording medium having a plurality of optical recording layers.

[0002]

2. Description of the Related Art In recent years, in the field of information recording, researches on optical information recording methods have been advanced in various places. This optical information recording system has a number of advantages such as non-contact recording / reproducing, read-only type, write-once type, and rewritable type memory formats. A wide range of applications from industrial to consumer use are considered as possible methods.

Increasing the capacity of the above-mentioned optical recording medium for various optical information recording systems (hereinafter, also referred to as an optical disk) is mainly due to the shortening of the wavelength of the laser light used as the light source used for the optical information recording system and the high aperture. This has been achieved by reducing the spot size on the focal plane by adopting the lens.

For example, in a CD (Compact Disc), the laser light wavelength is 780 nm and the lens aperture ratio (N
A) was 0.45 and had a capacity of 650 MB,
In DVD-ROM (digital versatile disk-playback-only memory), the laser light wavelength is 650 nm and the NA is 0.6.
And the capacity is 4.7 GB. Further, in the next-generation optical disc system, an optical disc in which a thin light-transmitting protective film (cover layer) of, for example, about 100 μm is formed on the optical recording layer is used, and the laser light wavelength is 450 nm or less and the NA is 0. 2 by setting it to 78 or more
A large capacity of 2 GB or more is possible.

By the way, in recent years, there has been an increasing demand for a large storage capacity of such an optical disc, and in order to meet this demand, for example, Japanese Patent Laid-Open No. 11-136432 discloses an optical system having two or more layers. An optical disk provided with a recording layer has been proposed. FIG. 26A is a schematic perspective view showing how light is emitted from an optical disc provided with the above-mentioned two optical recording layers. The optical disc DC has a substantially disc shape with a center hole CH opened in the center, and is rotationally driven in the drive direction DR. When recording or reproducing information, the objective lens OL having a numerical aperture of 0.8 or more is recorded on the optical recording layer in the optical disc DC.
Thus, light LT such as laser light in a blue to blue-violet region is emitted.

FIG. 26 (b) is a schematic sectional view of the above optical disk. An uneven shape 100 ′ is provided on one surface of a disk substrate 100 made of polycarbonate or the like having a thickness of about 1.1 mm. The first optical recording layer 101 is formed along the uneven shape 100 ′. The first optical recording layer 101 has a structure in which a recording film such as a dielectric film and a phase change film, a dielectric film, and a reflective film are laminated in this order from the upper layer side. Depends on material type and design. An intermediate layer 102 is formed on the first optical recording layer 101, and a second optical recording layer 103 is formed on the intermediate layer 102. Second optical recording layer 10
3 has a structure in which a recording film such as a dielectric film and a phase change film, a dielectric film, and a semi-transmissive reflective film are laminated in this order from the upper layer side. The layer structure and the number of layers are different from those of the recording material. It depends on the type and design. A light-transmitting protective sheet 105 is attached to the upper layer of the second optical recording layer 103 by an intermediate layer 104 made of an ultraviolet curable resin. The total thickness of the intermediate layer 104 and the protective sheet 105 is, for example, 0.1 mm.
The protective layer 106 having a film thickness of For example, the intermediate layer 10
2 has an uneven shape 102 ′ provided on the surface thereof, or has an uneven surface 104 ′ provided on the surface of the intermediate layer 104, and the second optical recording layer 103 has an uneven shape formed along the uneven shape. There is.

When recording or reproducing the above-mentioned optical disc, a light L such as a laser beam is passed through the objective lens OL.
T from the side of the light-transmitting protective layer 106 to the first optical recording layer 10
Irradiation is focused on the first or second optical recording layer 103. By adjusting the distance of the objective lens OL from the optical disc to focus on either the first optical recording layer 101 or the second optical recording layer 103, the first optical recording layer 101
And the second optical recording layer 103 is selectively recorded or reproduced. With the above configuration, the second optical recording layer 103 is semi-transmissive, and when the light LT is applied to the first optical recording layer 101, it is transmitted through the second optical recording layer 103. During reproduction of the optical disc, the return light reflected by either the first or second optical recording layer (101, 103) is received by the light receiving element, and the signal processing circuit generates a predetermined signal to reproduce the reproduction signal. Is taken out.

In the optical disc as described above, the first optical recording layer 101 and the second optical recording layer 103 each have an uneven shape 1 formed on the surface of the disc substrate 100.
00 'or the uneven shape 1 formed on the surface of the intermediate layer 102
02 'and the like have an uneven shape. For example,
The track region is divided by the uneven shape including the recess. The track areas divided by the above-mentioned recesses are called lands and grooves, and the capacity can be increased by applying a land / groove recording system for recording information on both lands and grooves. It is also possible to use only one of the land and the groove as the recording area.

Further, the optical recording film is formed by reflecting the optical recording film such as an aluminum film by using the uneven shape resulting from the uneven shape of the disk substrate 100 or the intermediate layer 104 or the intermediate layer 102 as a pit having a length corresponding to the recording data. By using a film, a read-only (ROM) type optical disk can be obtained.

As a method of manufacturing an optical disc having the above-mentioned two optical recording layers, for example, a disc substrate 100 having a concavo-convex shape (or pit pattern) formed on one side by injection molding is prepared, and a first optical layer is formed thereon. Recording layer 10
27, and then, as shown in FIG. 27, a resin 102a to be an intermediate layer is supplied by spin coating or the like, and is cured by pressing a metal stamper such as nickel having an uneven shape against the intermediate layer. The concavo-convex shape (or pit pattern) is transferred to the surface, the second optical recording layer is formed on the concavo-convex forming surface, and the protective layer is formed thereon.

[0011]

However, in the step of supplying the resin 102a to be the intermediate layer by spin coating or the like, there is a problem that the resin thickness becomes thicker on the outer peripheral portion of the disk due to the centrifugal force during spinning. It was This is because an optical disk generally has a center hole at the center, and the center hole is used for handling during disk manufacturing and mounting on the disk reproducing device. This is because the ultraviolet curable resin has to be applied to a place deviated from the position, which causes the resin thickness to increase at the outer peripheral portion of the disk.

In a high-density multi-layer optical disc, in order to read the disc information with high accuracy by a laser pickup, the thickness of the protective layer of the optical recording layer and the thickness of the intermediate layer between the optical recording layers are made uniform within the disc surface. Is required to do.

In particular, the problem that sputtered flakes generated when a reflective film as an optical recording layer is sputtered remains on the reflective film is an unavoidable problem when sputtering is performed with good productivity in a short time. There is. Since the spatter flakes adhere so strongly that they cannot be removed even by air blow, in order to prevent the uneven thickness from being affected by the spatter flakes by embedding the spatter flakes of about 10 μm in the UV curable resin layer. Although it is desirable that the thickness is 15 μm or more, on the other hand, when the sheet-shaped substrate is bonded to the disc substrate via the UV-curable resin, for example, the thickness of the UV-curable resin is uneven in the region of the optical disc having a diameter of 12 cm. ± 2 μm
If it is attempted to suppress it, the average value of the thickness of the ultraviolet curable resin must be suppressed to 10 μm or less. Even under such a situation, it becomes difficult to suppress the unevenness of the ultraviolet curable resin film thickness within ± 2 μm. Was there.

On the other hand, for example, Japanese Patent Laid-Open No. 10-289489 discloses that when a viscous liquid is applied to the center of a disk substrate having no center hole and spin-coated, the film thickness becomes uniform over the entire area of the circular base material. However, it takes time and effort to close the center holes at the center of the disks one by one to make them flat.

The present invention has been made in view of the above situation. Therefore, the object of the present invention is to suppress uneven thickness when spin coating a resin material constituting an intermediate layer,
In particular, it is an object of the present invention to provide a method for manufacturing an optical recording medium capable of suppressing unevenness in thickness even if sputter flakes are present.

[0016]

In order to achieve the above object, the method for producing an optical recording medium of the present invention is a substantially disc shape having a center hole in the center and has at least two optical recording layers. A method of manufacturing an optical recording medium, comprising:
A step of forming a first substrate having a substantially disc shape having a center hole in the center and having an uneven shape on one surface, and a step of forming a first optical recording layer on the uneven surface of the medium substrate, The concavo-convex shape is transferred onto one surface of the second substrate, which is a substantially circular sheet having no center hole at the center, and
A step of forming a second optical recording layer on the surface of the substrate on which the concavo-convex shape is formed; a step of opening a center hole at the center of the second substrate;
Bonding the substrate to the second optical recording layer side with a bonding layer.

In the above-mentioned method for producing an optical recording medium of the present invention, preferably, the uneven shape is transferred onto one surface of the second substrate having a substantially circular sheet shape having no center hole at the center,
In the step of forming the second optical recording layer on the uneven surface on which the second substrate is formed, the intermediate layer material is supplied onto one surface of the second substrate, and spin coating is performed to have the uneven shape. A step of adhering to the stamper on which the second optical recording layer is formed on the surface on which the uneven shape is formed and solidifying the intermediate layer material to form an intermediate layer; and peeling at the interface between the second optical recording layer and the stamper. And transferring the concavo-convex shape to the intermediate layer and transferring the second optical recording layer onto the intermediate layer. More preferably, the stamper is a resin stamper.

In the above-described method for producing an optical recording medium of the present invention, preferably, the uneven shape is transferred onto one surface of the second substrate having a substantially circular sheet shape having no center hole at the center,
In the step of forming the second optical recording layer on the concave-convex shape forming surface of the second substrate, the intermediate layer material is supplied onto one surface of the second substrate and spin coating is performed to form the concave-convex shape. A step of adhering to the stamper and solidifying the intermediate layer material to form an intermediate layer; a step of peeling at the interface between the intermediate layer and the stamper to transfer the uneven shape to the intermediate layer; and an unevenness of the intermediate layer Forming a second optical recording layer on the shape forming surface. More preferably, the stamper is a glass stamper.

In the above-described method for producing an optical recording medium of the present invention, preferably, the uneven shape is transferred onto one surface of the second substrate having a substantially circular sheet shape having no center hole at the center,
In the step of forming the second optical recording layer on the uneven surface on which the second substrate is formed, the intermediate layer material is supplied onto a stamper having no center hole in the center and having an uneven surface to spin the film. A step of applying the same to one surface of the second substrate by coating and solidifying the intermediate layer material to form an intermediate layer; a step of peeling at the interface between the intermediate layer and the stamper; and an uneven shape of the intermediate layer. Forming a second optical recording layer on the formation surface. More preferably, the stamper is a metal stamper.

In the above-described method for producing an optical recording medium of the present invention, preferably, the uneven shape is transferred onto one surface of the second substrate having a substantially circular sheet shape having no center hole at the center,
After the step of forming the second optical recording layer on the concave-convex shape forming surface of the second substrate, an intermediate layer is formed on the upper layer of the second optical recording layer to transfer the concave-convex shape, and then the concave-convex shape forming surface is formed. The step of forming the optical recording layer is repeated at least once.

In the above-described method for manufacturing an optical recording medium of the present invention, since the uneven shape is transferred to one surface of the second substrate which is a substantially circular sheet having no center hole in the center, one surface of the second substrate is not transferred. When a resin material to be an intermediate layer is spin-coated in order to transfer the uneven shape to the surface, the resin can be supplied to the central portion of the substantially circular sheet-shaped second substrate. Alternatively,
When a resin material to be an intermediate layer is spin-coated on a stamper having no center hole in the center and an uneven surface, the resin can be supplied to the center of the stamper. Therefore, the resin material serving as the intermediate layer can be applied while suppressing unevenness in thickness, and even when the resin layer serving as the intermediate layer is formed thick so as to bury sputter flakes, unevenness in thickness can be suppressed.

In order to achieve the above object, the method for producing an optical recording medium of the present invention is an optical recording medium having a substantially disk shape having a center hole in the center and having at least one optical recording layer. A manufacturing method, which does not have a center hole in the center, and supplies an intermediate layer material on a stamper having an uneven surface, and by spin coating, is attached to one surface of a substantially disk-shaped medium substrate, Solidifying the intermediate layer material to form an intermediate layer, transferring the uneven shape to one surface of the medium substrate, and forming an optical recording layer on the uneven surface of the medium substrate, The method includes at least a step of opening a center hole in the center of the optical recording layer, and a step of forming a protective layer on the optical recording layer.

In the above-described method for producing an optical recording medium of the present invention, preferably, the intermediate layer material is supplied onto a stamper having no center hole in the center and having an uneven shape on the surface,
In the step of bonding by spin coating to one surface of the substantially disk-shaped medium substrate, solidifying the intermediate layer material to form an intermediate layer, and transferring the uneven shape to the one surface of the medium substrate, In the step of adhering a medium substrate having no center hole in the center with the intermediate layer material spin-coated on the stamper and opening the center hole at least in the center of the optical recording layer, the medium substrate, the intermediate A center hole is opened in the center of the layer and the optical recording layer. Further, preferably, the stamper is a metal stamper.

In the above-mentioned method for producing an optical recording medium of the present invention, preferably, after the step of forming the optical recording layer on the uneven surface of the medium substrate, an intermediate layer is formed on the optical recording layer. The step of forming and transferring the uneven shape and forming the optical recording layer on the uneven surface is repeated at least once.

In the above-described method for producing an optical recording medium of the present invention, when a resin material to be an intermediate layer is spin-coated on a stamper having no center hole in the center and an uneven surface, Resin can be supplied to the central portion. Therefore, the resin material serving as the intermediate layer can be applied while suppressing unevenness in thickness, and even when the resin layer serving as the intermediate layer is formed thick so as to bury sputter flakes, unevenness in thickness can be suppressed.

In order to achieve the above object, the method for producing an optical recording medium of the present invention is an optical recording medium having a substantially disc shape having a center hole in the center and having at least one optical recording layer. A manufacturing method, which is a step of forming a first substrate having a substantially disk shape having a center hole in the center and having an uneven shape on one surface, and an optical recording layer on the uneven surface on which the first substrate is formed. A step of forming a second circular plate-shaped second substrate having no center hole at the center on the optical recording layer side of the first substrate by a bonding layer; and a step of bonding the second substrate to the center of the second substrate. And a step of opening the center hole.

In the above-described method for producing an optical recording medium of the present invention, preferably, a second substrate having a substantially circular sheet shape having no center hole in the center is attached to the optical recording layer side of the first substrate. In the matching step, the bonding layer material is supplied onto one surface of the second substrate and spin coating is performed to form the first layer.
Bonding the substrate to the optical recording layer side and solidifying the bonding layer material to form a bonding layer.

In the above-mentioned method for producing an optical recording medium of the present invention, it is preferable that a substantially circular sheet-shaped second substrate having no center hole at the center is attached to the optical recording layer side of the first substrate. Prior to the step of laminating with the bonding layer, the step of forming an intermediate layer on one surface of the second substrate to transfer the uneven shape and forming the optical recording layer on the uneven surface is performed at least once. In the step of attaching a substantially circular sheet-shaped second substrate having no center hole at the center to the optical recording layer side of the first substrate by an attachment layer, the optical recording layer side of the first substrate is included. And the optical recording layer side of the second substrate are bonded together.

In the above-described method for manufacturing an optical recording medium of the present invention, since the second substrate in the shape of a substantially circular sheet having no center hole in the center is bonded by the bonding layer, the bonding for bonding the second substrate is performed. In the case of spin-coating the resin material to be the alignment layer, the resin can be supplied to the central portion of the substantially circular sheet-shaped second substrate. Therefore, it is possible to apply the resin material serving as the bonding layer while suppressing the thickness unevenness. Particularly, even when the resin layer serving as the bonding layer is formed thick so as to fill the sputter flakes, the thickness unevenness can be suppressed and formed. it can.

In order to achieve the above-mentioned object, the method for producing an optical recording medium of the present invention is an optical recording medium having a substantially disc shape having a center hole in the center and having at least one optical recording layer. In the manufacturing method, one surface has a concavo-convex shape, a portion serving as a center center hole is thinner than other portions, and the thinned portion on the concavo-convex shape forming surface side Forming a substantially disk-shaped medium substrate having a flat surface; forming an optical recording layer on the uneven surface of the medium substrate; and forming a protective layer on the optical recording layer. And a step of forming a center hole by opening a thinned portion in the center of the medium substrate.

In the above-mentioned method for producing an optical recording medium of the present invention, preferably, the step of forming the protective layer comprises a step of supplying a protective layer material onto the optical recording layer of the medium substrate by spin coating. Solidifying the protective layer material to form a protective layer.

In the above-mentioned method for producing an optical recording medium of the present invention, preferably, in the step of forming the protective layer, a bonding layer material constituting the protective layer is supplied on the optical recording layer of the medium substrate. , A step of bonding by spin coating to a substantially circular sheet substrate having no center hole in the center, and a step of solidifying the bonding layer material to form a protective layer.

In the above-described method for producing an optical recording medium of the present invention, one surface has a concavo-convex shape, the center center hole is thinner than the other part, and the concavo-convex shape is formed. When a disk-shaped medium substrate having a flat surface on the surface side of the thinned portion is used, and when a resin material to be a protective layer is spin-coated, the resin is supplied to the central portion of the medium substrate. be able to. Therefore, the resin material serving as the protective layer can be applied while suppressing the thickness unevenness, and the thickness unevenness can be suppressed even when the resin layer serving as the protective layer is formed thick so as to fill the sputter flakes.

In order to achieve the above object, the method for producing an optical recording medium according to the present invention is an optical recording medium having a substantially disc shape having a center hole in the center and having at least two optical recording layers. In the manufacturing method, one surface has a concavo-convex shape, a portion serving as a center center hole is thinner than other portions, and the thinned portion on the concavo-convex shape forming surface side A step of forming a substantially disk-shaped first substrate having a flat surface, and a step of forming a first optical recording layer on the uneven surface on which the first substrate is formed,
Transferring a concavo-convex shape to one surface of a substantially circular sheet-like second substrate having no center hole in the center, and forming a second optical recording layer on the concavo-convex shape forming surface of the second substrate; A step of bonding the first optical recording layer side of the first substrate and the second optical recording layer side of the second substrate with a bonding layer; and opening a thinned portion at the center of the first substrate. And forming a center hole.

In the above-mentioned method for producing an optical recording medium of the present invention, preferably, the first optical recording layer side of the first substrate and the second optical recording layer side of the second substrate are laminated together. The step of bonding by means of supplying a bonding layer material on the first optical recording layer of the first substrate and bonding the same with the second optical recording layer side of the second substrate by spin coating; Solidifying the mating layer material.

In the method for producing an optical recording medium according to the present invention, one surface has an uneven shape, the central center hole is thinner than the other area, and the uneven shape is formed. A substantially disk-shaped first substrate in which the surface of the thinned portion on the surface side is flat is used.
In the case of spin-coating a resin material to be a bonding layer for bonding with the substrate, the resin can be supplied to the central portion of the first substrate. Therefore, it is possible to apply the resin material serving as the bonding layer while suppressing the thickness unevenness. Particularly, even when the resin layer serving as the bonding layer is formed thick so as to fill the sputter flakes, the thickness unevenness can be suppressed and formed. it can.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. The present embodiment relates to a method for manufacturing an optical recording medium (optical disc).

First Embodiment FIG. 1A is a schematic perspective view showing a state of light irradiation of an optical disk having two optical recording layers according to this embodiment. The optical disc DC has a substantially disc shape with a center hole CH opened in the center, and is rotationally driven in the drive direction DR. When recording or reproducing information, the optical recording layer in the optical disc DC is irradiated with light LT such as laser light in a blue to blue-violet region by an objective lens OL having a numerical aperture of 0.8 or more, for example. .

FIG. 1 (b) is a schematic sectional view taken along the line AA 'in FIG. 1 (a). For example, the thickness is 1.1 mm, the outer diameter is 120 mm, and the inner diameter of the center hole CH is 15 m.
A first optical recording layer 16 is formed on one surface of a disc substrate (first substrate) 15 made of polycarbonate or the like, which is m. The first optical recording layer 16 has a structure in which a recording film such as a dielectric film and a phase change film, a dielectric film and a reflective film are laminated in this order from the upper layer side. Depends on material type and design. First
An intermediate layer 17 having a film thickness of, for example, about 20 μm is formed on the optical recording layer 16 and a second optical recording layer 12 is formed on the intermediate layer 17. The second optical recording layer 12 has a structure in which a recording film such as a dielectric film and a phase change film, a dielectric film and a semi-transmissive reflective film are laminated in this order from the upper layer side. Depends on the type and design of the recording material. A light-transmissive sheet-like substrate (second substrate) 13 is attached to the upper layer of the second optical recording layer 12 by an intermediate layer 14 made of an ultraviolet curable resin. The intermediate layer 14 and the sheet-shaped substrate 13 are combined to form a protective layer 18 having a film thickness of 0.1 mm, for example.

The disc substrate (first substrate) 15 is provided with an uneven shape 15 ′ on one surface thereof, and the first optical recording layer 16 is formed along the uneven shape. In addition, the surface of the intermediate layer 14 is also provided with an uneven shape 14 ',
The second optical recording layer 12 is formed along this uneven shape.

When recording or reproducing the above-mentioned optical disc, as shown in FIG. 1B, the light LT such as a laser beam is transmitted from the side of the protective layer 18 which is transparent to the first optical recording layer by the objective lens OL. 16 or the second optical recording layer 12 is irradiated so as to be focused. Which of the first optical recording layer 16 and the second optical recording layer 12 is selected depending on which of the first optical recording layer 16 and the second optical recording layer 12 is focused by adjusting the distance of the objective lens OL from the optical disc. Selectively record or play. With the above configuration, the second optical recording layer 1
2 is semi-transmissive, and when the light LT is applied to the first optical recording layer 16, the light is transmitted through the second optical recording layer 12.
During reproduction of the optical disc, the return light reflected by either the first or second optical recording layer (16, 12) is received by the light receiving element, and a predetermined signal is generated by the signal processing circuit to generate a reproduction signal. Is taken out.

In the optical disc as described above, the first optical recording layer 16 and the second optical recording layer 12 have an uneven shape 15 'formed on the surface of the disk substrate 15 or an uneven shape formed on the surface of the intermediate layer 14. It has an uneven shape due to 14 '. For example, the track region is divided by this uneven shape. The track area divided by the above-mentioned uneven shape is called a land and a groove,
The capacity can be increased by applying the land / groove recording method for recording information on both the land and the groove.
It is also possible to use only one of the land and the groove as the recording area.

Further, the uneven shape resulting from the uneven shapes (15 ', 14') of the disk substrate 15 and the intermediate layer 14 is defined as a pit having a length corresponding to the recording data.
By forming the optical recording film with a reflective film such as an aluminum film, a read-only (ROM) type optical disk can be obtained.

Next, a method of manufacturing an optical disc having the above-mentioned two optical recording layers will be described. In particular, the concavo-convex shape (15 ′, 1 of the disk substrate 15 and the intermediate layer 14
4 ') is a pit pattern, and the first and second optical recording films are respectively made of aluminum film for reproduction only (RO
It will be described as an M) type optical disc.

First, a disk second optical recording layer stamper 10 having an uneven shape 10 'which is a pit pattern for the second optical recording layer on the surface thereof is prepared by a conventionally known method. Next, the second optical recording layer stamper 10 is installed so as to face the inside of the cavity of the mold, and as shown in FIG. 2 (a), for example, by injection molding in which a molten acrylic resin is injected. A resin stamper 11 for the second optical recording layer made of an acrylic resin is prepared. On the surface of the resin stamper 11 for the second optical recording layer, the uneven shape 1 of the stamper 10 for the second optical recording layer is formed.
An uneven shape 11 ′ is formed corresponding to 0 ′.

By releasing from the stamper 10 for the second optical recording layer, the resin for the second optical recording layer having the unevenness 11 'which becomes a pit pattern is formed on the surface as shown in FIG. 2 (b). The stamper 11 made can be obtained.

Next, as shown in FIG. 2C, air or a gas such as nitrogen gas is blown onto the surface of the resin stamper 11 for the second optical recording layer to remove dust, and then, for example, by a sputtering method or the like. Then, aluminum is deposited to form the second optical recording layer 12 which is a semi-transmissive reflective film.

Next, as shown in FIG. 3A, a substantially circular sheet-like substrate (second substrate) having no center hole at the center, preferably having a thickness of 100 μm or less, for example 80 μm.
13 is brought into close contact with a rotary table RT which has a flat surface and can be driven to rotate. The method of adhesion may be, for example, vacuum suction, sticking to the stage via a slightly adhesive sheet, or applying static electricity to the stage. Next, an appropriate amount of ultraviolet curable resin 14a, which serves as an intermediate layer, is supplied to the central portion of the sheet-like substrate 13 and spin coated.

Next, as shown in FIG. 3B, the resin stamper 11 for the second optical recording layer, in which the second optical recording layer 12 is formed on the ultraviolet curable resin 14a, is attached to the second optical recording layer. The layers are bonded from the 12 side, and a sufficient amount of ultraviolet rays are irradiated to solidify the ultraviolet curable resin 14a to form the intermediate layer 14.
Here, a concavo-convex shape 14 'is formed on the surface of the intermediate layer 14, corresponding to the concavo-convex shape 11' of the resin stamper 11 for the second optical recording layer.

In the above spin coating and laminating steps, the ultraviolet curable resin 14a is supplied to the central portion of the sheet-like substrate 13 and the second optical recording layer 12 side is made the lower surface above the second optical recording layer 12a. The resin stamper 11 for use is arranged and spun to spread the ultraviolet curable resin 14a in the gap between the sheet-shaped substrate 13 and the second optical recording layer 12,
It is also possible to irradiate a sufficient amount of ultraviolet rays to solidify the ultraviolet curable resin 14a to form the intermediate layer 14.

Next, as shown in FIG. 3C, by peeling at the interface between the resin stamper 11 for the second optical recording layer and the second optical recording layer 12, the uneven shape 1 is formed on the surface of the intermediate layer 14.
4 ′ is transferred and the second optical recording layer 12 is transferred onto the intermediate layer 14. The adhesive force between the resin stamper 11 for the second optical recording layer made of an acrylic resin and the second optical recording layer 12 made of the aluminum reflective film is the same as the second optical recording layer 1
Since the adhesive strength between the second optical recording layer 12 and the intermediate layer 14 which is a cured ultraviolet curable resin is weaker, the second optical recording layer 12 itself is transferred together with the transfer of the uneven shape as described above.

Next, a center hole CH is formed in the sheet-like base material 13 on which the second optical recording layer 12 is formed,
If necessary, trim the outer circumference to an appropriate size. On the other hand, in a separate process, the stamper for the first optical recording layer is installed so as to face the inside of the cavity of the mold, and for example, injection molding is performed by injecting a polycarbonate in a molten state to obtain a substantially disc shape having a center hole CH in the center. Forming a disk substrate (first substrate) 15 on the surface of which unevenness 15 'for the first optical recording layer is formed, and depositing aluminum by, for example, a sputtering method,
The first optical recording layer 16 which is a total reflection film is formed, and the pressure-sensitive adhesive sheet 17a is arranged on the first optical recording layer 16. Next, FIG.
As shown in (a), the first optical recording layer 16 side of the disc substrate 15 and the second optical recording layer 12 of the sheet substrate 13 are used as the intermediate layer 17 for bonding the pressure-sensitive adhesive sheet 17a.
Face each other, align the cores, and bond them together.
The configuration shown in (b) is adopted. As described above, the optical disc having the configuration shown in FIG. 1 can be manufactured.

According to the method of manufacturing an optical disk in the present embodiment, the intermediate layer 14 is formed on one surface of the substantially circular sheet-like substrate (second substrate) 13 having no center hole in the center.
Is formed and the uneven shape 14 'is transferred to the surface,
The intermediate layer 14 is provided on one surface of the sheet-like substrate (second substrate) 13.
The resin can be supplied to the central portion of the substantially circular sheet-shaped substrate 13 when spin-coating the resin material that becomes
Therefore, the resin material for the intermediate layer 14 can be applied while suppressing unevenness in thickness, and in particular, even if the resin layer serving as an intermediate layer is formed thick so as to embed sputter flakes, unevenness in thickness can be suppressed and formed. .

In this embodiment, the sheet-shaped substrate 13
As the resin stamper 11 for the second optical recording layer for transferring the uneven shape to the ultraviolet curable resin 14a applied thereon, both of them can be used with or without a center hole in the center.

Second Embodiment The optical disc according to the present embodiment has substantially the same configuration as the optical disc according to the first embodiment, but has an optical recording layer of three layers. The method for manufacturing the optical disc according to the present embodiment will be described below.

First, as shown in FIG. 5A, a substantially circular sheet-like substrate (second substrate) having no center hole at the center, preferably having a thickness of 100 μm or less, for example, 80 μm.
20 is brought into close contact with a rotary table RT which has a flat surface and can be driven to rotate. The method of adhesion may be, for example, vacuum suction, sticking to the stage via a slightly adhesive sheet, or applying static electricity to the stage. Next, an appropriate amount of ultraviolet curable resin 21a, which serves as an intermediate layer, is supplied to the central portion of the sheet-shaped substrate 20 for spin coating.

In a separate step, the glass stamper 22 for the third optical recording layer, on which the concave-convex shape 22 'for the third optical recording layer is formed, is formed, and as shown in FIG. The resin 21a is adhered to the glass stamper 22 for the third optical recording layer from the concave / convex shape 22 'side and irradiated with a sufficient amount of ultraviolet rays to solidify the ultraviolet curable resin 21a,
The intermediate layer 21 is used. Here, on the surface of the intermediate layer 21, the uneven shape 22 'of the glass stamper 22 for the third optical recording layer is formed.
Correspondingly, the uneven shape 21 'is formed.

In the steps of spin coating and bonding, the ultraviolet curable resin 21a is supplied to the central portion of the sheet-like substrate 20 and the concave and convex shape 22 'is formed on the upper surface of the ultraviolet curable resin 21a to make the lower surface of the glass substrate for the third optical recording layer. Place the stamper 22,
The UV curable resin 21a is formed in the gap between the sheet-shaped substrate 20 and the glass stamper 22 for the third optical recording layer by spinning.
Alternatively, the ultraviolet curable resin 21a may be solidified by irradiating a sufficient amount of ultraviolet light to form the intermediate layer 21.

Next, as shown in FIG. 5C, by peeling at the interface between the glass stamper 22 for the third optical recording layer and the intermediate layer 21, an uneven shape 21 ′ is transferred to the surface of the intermediate layer 21. To do.

Next, as shown in FIG. 6A, the intermediate layer 2
After air and a gas such as nitrogen gas are blown to the surface on which the concave-convex shape 21 'of 1 is formed to remove dust, a recording film such as a dielectric film or a phase change film, a dielectric film and a semitransparent film are formed by, for example, a sputtering method. The third optical recording layer 23 is formed by laminating the reflective films of the above in this order. The layer structure and the number of layers differ depending on the type and design of the recording material. In the case of a read-only (ROM) type optical disc, aluminum is deposited to form a semi-transparent third optical recording layer.

Next, as shown in FIG. 6B, the sheet-shaped substrate 20 on which the third optical recording layer 23 is formed is placed on the rotary table RT, and the central portion on the third optical recording layer 23 is placed. Then, an appropriate amount of ultraviolet curable resin 24a to be an intermediate layer is supplied to the substrate and spin coating is performed.

In a separate step, the glass stamper 25 for the second optical recording layer, on which the concave-convex shape 25 'for the second optical recording layer is formed, is formed, and as shown in FIG. The resin 24a is adhered to the second optical recording layer glass stamper 25 from the uneven shape 25 'side and irradiated with a sufficient amount of ultraviolet rays to solidify the ultraviolet curable resin 24a,
The intermediate layer 24 is used. Here, on the surface of the intermediate layer 24, the concavo-convex shape 25 ′ of the glass stamper 25 for the second optical recording layer is provided.
Correspondingly, the uneven shape 24 'is formed.

In the above spin coating and laminating steps, the ultraviolet curable resin 24a is supplied to the central portion of the third optical recording layer 23, and the uneven shape 25 'is formed on the upper surface of the second optical recording layer 23 as the lower surface. The glass stamper 25 for glass is placed and spun to spread the ultraviolet curable resin 24a in the gap between the third optical recording layer 23 and the glass stamper 25 for the second optical recording layer, and irradiate a sufficient amount of ultraviolet rays. Alternatively, the ultraviolet curable resin 24a may be solidified to form the intermediate layer 24.

Next, as shown in FIG. 7A, by peeling at the interface between the glass stamper 25 for the second optical recording layer and the intermediate layer 24, the uneven shape 24 'is transferred to the surface of the intermediate layer 24. To do.

Next, as shown in FIG. 7B, the intermediate layer 2
After air and a gas such as nitrogen gas are blown to the surface of the concave-convex shape 24 ′ of 4 to remove dust, the recording film, the dielectric film and the semi-transparent film, such as a dielectric film or a phase change film, is formed by, for example, a sputtering method. The reflective film and the like are laminated in this order to form the second optical recording layer 26. The layer structure and the number of layers differ depending on the type and design of the recording material. In the case of a read-only (ROM) type optical disc, aluminum is deposited to form a semi-transparent second optical recording layer.

Next, a center hole CH is formed in the sheet-like base material 20 on which the second optical recording layer 26 and the third optical recording layer 23 are formed, and if necessary, the outer peripheral portion is appropriately sized. Trim to. On the other hand, in a separate process, the stamper for the first optical recording layer is installed so as to face the inside of the cavity of the mold, and the center hole CH is formed in the center by injection molding in which molten polycarbonate is injected.
Disk substrate (first substrate) having a substantially disc shape having a concave and convex shape 27 'for the first optical recording layer formed on the surface thereof
27 is formed, and a dielectric film, a recording film such as a phase change film, a dielectric film, a total reflection film, and the like are laminated in this order by, for example, a sputtering method, to form a first optical recording layer 28. The layer structure and the number of layers differ depending on the type and design of the recording material. In the case of a read-only (ROM) type optical disc, aluminum is deposited to form the first optical recording layer having total reflection.

Next, a pressure-sensitive adhesive sheet 29a is placed on the upper layer of the first optical recording layer 28, and the pressure-sensitive adhesive sheet 29a is used as an intermediate layer 29 for laminating the disc substrate 27 on the side of the first optical recording layer 28. Then, the sheet-shaped substrate 20 and the second optical recording layer 26 side are opposed to each other, the cores are aligned, and the sheets are bonded together. Thus, the optical disc having the configuration shown in FIG. 8B can be manufactured.

According to the optical disc manufacturing method of the present embodiment, the intermediate layer 21 is formed on one surface of the substantially circular sheet-like substrate (second substrate) 20 having no center hole in the center.
Is formed and the uneven shape 21 'is transferred to the surface,
The intermediate layer 21 is provided on one surface of the sheet-like substrate (second substrate) 20.
The resin can be supplied to the central portion of the substantially circular sheet-shaped substrate 20 when spin-coating a resin material that becomes
Further, when a resin material for the intermediate layer 24 is spin-coated on the upper layer, the resin can be supplied to the central portion on the third optical recording layer 23. Therefore, the intermediate layer (2
1, 24) can be applied while suppressing unevenness in thickness, and even if the resin layer serving as an intermediate layer is thickly formed so as to embed sputter flakes, uneven thickness can be suppressed and formed.

In this embodiment, the sheet substrate 20 is used.
As the glass stamper 22 for the third optical recording layer for transferring the uneven shape to the ultraviolet curable resin 21a applied on the both, it is possible to use either with or without a center hole in the center.

Third Embodiment The optical disc according to the present embodiment has a three-layer optical recording layer, like the optical disc according to the second embodiment. The method for manufacturing the optical disc according to the present embodiment will be described below.

First, as shown in FIG. 9 (a), a rotary table which is made of nickel or the like and has a substantially circular third optical recording layer stamper 30 having no center hole in the center thereof and having a flat surface can be rotationally driven. Stick to RT. The contact method is
Vacuum suction or magnet suction may be used. Next, an appropriate amount of ultraviolet curable resin 31a to be an intermediate layer is supplied to the central portion of the third optical recording layer stamper 30 for spin coating.

Next, as shown in FIG. 9B, a substantially circular sheet-like substrate (second substrate) 32 having no center hole in the center is attached to the ultraviolet curable resin 31a, and a sufficient amount of the substrate 32 is attached. The intermediate layer 31 is formed by irradiating ultraviolet rays to solidify the ultraviolet curable resin 31a. Here, an uneven shape 31 ′ is formed on the surface of the intermediate layer 31, corresponding to the uneven shape 30 ′ of the stamper 30 for the third optical recording layer.

In the spin coating and laminating steps described above, the ultraviolet curable resin 31a is supplied to the central portion of the stamper 30 for the third optical recording layer, and the sheet-like substrate 32 is placed on top of it and spun. Sheet substrate 32
Alternatively, the intermediate layer 31 may be formed by spreading the ultraviolet curable resin 31a in the gap between the third optical recording layer stamper 30 and irradiating a sufficient amount of ultraviolet rays to solidify the ultraviolet curable resin 31a.

Next, as shown in FIG. 10A, by peeling at the interface between the third optical recording layer stamper 30 and the intermediate layer 31, an uneven shape 31 ′ is transferred to the surface of the intermediate layer 31.

Next, as shown in FIG. 10 (b), a gas such as air or nitrogen gas is blown on the surface of the intermediate layer 31 on which the concave-convex shape 31 'is formed to remove dust, and then, for example, by a sputtering method or the like. A third optical recording layer 33 is formed by laminating a recording film such as a dielectric film and a phase change film, a dielectric film and a semi-transmissive reflective film in this order. The layer structure and the number of layers differ depending on the type and design of the recording material. In the case of a read-only (ROM) type optical disc, aluminum is deposited to form a semi-transparent third optical recording layer.

Next, as shown in FIG. 11A, a substantially circular second optical recording layer stamper 34 made of nickel or the like and having no center hole at the center has a flat surface and can be rotationally driven. Stick it to the table RT. The method of adhesion may be vacuum attraction, magnet attraction or the like. Next, an appropriate amount of ultraviolet curable resin 35a, which serves as an intermediate layer, is supplied to the central portion of the second optical recording layer stamper 34, and spin coating is performed.

Next, as shown in FIG. 11B, the sheet substrate 32 is attached to the ultraviolet curable resin 35a from the side of the third optical recording layer 33, and a sufficient amount of ultraviolet rays is irradiated to the ultraviolet curable resin 35a. 35a is solidified to form the intermediate layer 35. Here, an uneven shape 35 ′ is formed on the surface of the intermediate layer 35 so as to correspond to the uneven shape 34 ′ of the second optical recording layer stamper 34.

In the steps of spin coating and bonding, the ultraviolet curable resin 35a is supplied to the central portion of the stamper 34 for the second optical recording layer, and the third optical recording layer 33 is placed on the upper portion of the ultraviolet curable resin 35a to form a sheet shape. The ultraviolet curable resin 35a is spread over the gap between the third optical recording layer 33 and the stamper 34 for the second optical recording layer by disposing the substrate 32 and spinning it, and the ultraviolet curable resin 35a is irradiated with a sufficient amount of ultraviolet rays.
May be solidified to form the intermediate layer 35.

Next, as shown in FIG. 12A, by peeling at the interface between the second optical recording layer stamper 34 and the intermediate layer 35, the uneven shape 35 ′ is transferred to the surface of the intermediate layer 35.

Next, as shown in FIG. 12 (b), a gas such as air or nitrogen gas is blown onto the surface of the intermediate layer 35 on which the concavo-convex shape 35 'is formed to remove dust, and then, for example, by a sputtering method or the like. A second optical recording layer 36 is formed by laminating a recording film such as a dielectric film and a phase change film, a dielectric film and a semi-transmissive reflective film in this order. The layer structure and the number of layers differ depending on the type and design of the recording material. In the case of a read-only (ROM) type optical disc, aluminum is deposited to form a semi-transparent second optical recording layer.

Next, a center hole CH is formed in the sheet-like base material 32 on which the second optical recording layer 36 and the third optical recording layer 33 are formed, and if necessary, the outer peripheral portion is appropriately sized. Trim to. On the other hand, in a separate process, the stamper for the first optical recording layer is installed so as to face the inside of the cavity of the mold, and the center hole CH is formed in the center by injection molding in which molten polycarbonate is injected.
A disk substrate (first substrate) having a substantially disc shape having a concave and convex shape 37 'for the first optical recording layer formed on the surface thereof.
37 is formed and, for example, a dielectric film, a recording film such as a phase change film, a dielectric film and a total reflection film are laminated in this order by, for example, a sputtering method or the like to form a first optical recording layer 38. The layer structure and the number of layers differ depending on the type and design of the recording material. In the case of a read-only (ROM) type optical disc, aluminum is deposited to form the first optical recording layer having total reflection.

Next, a pressure-sensitive adhesive sheet 39a is placed on the upper layer of the first optical recording layer 38, and the pressure-sensitive adhesive sheet 39a is used as an intermediate layer 39 for laminating the disc substrate 37 on the side of the first optical recording layer 38. The optical disc having the structure shown in FIG. 13B can be manufactured by facing the sheet-shaped substrate 32 to the side of the second optical recording layer 36, aligning the cores, and adhering.

According to the optical disc manufacturing method of the present embodiment, the uneven shape is transferred onto one surface of the substantially circular sheet-like substrate (second substrate) 32 having no center hole in the center. A stamper (30, 34 ') having no center hole in the center and having an uneven shape (30'34') on the surface
34) on which a resin material (31
a, 35a) is spin coated, the stamper (3
The resin can be supplied to the central portion of (0, 34). Therefore, the resin material to be the intermediate layers (31, 35) can be applied while suppressing the thickness unevenness, and in particular, even if the resin layer serving as the intermediate layer is formed thick so as to fill the sputter flakes, the thickness unevenness is suppressed. can do.

Fourth Embodiment The optical disc according to the present embodiment has substantially the same configuration as the optical disc according to the first embodiment. The method for manufacturing the optical disc according to the present embodiment will be described below.

First, as shown in FIG. 14A, a rotary table made of nickel or the like and having a substantially circular first optical recording layer stamper 40 having no center hole at the center and having a flat surface and capable of being rotationally driven. Stick to RT. The method of adhesion may be vacuum attraction, magnet attraction or the like. Next, an appropriate amount of ultraviolet curable resin 41a, which serves as an intermediate layer, is supplied to the central portion of the stamper 40 for the first optical recording layer, and spin coating is performed.

Next, as shown in FIG. 14B, a disc substrate (first substrate) 42 having a substantially disk shape with no center hole in the center is attached to the ultraviolet curable resin 41a, and a sufficient amount is applied. UV curable resin 41a
Is solidified to form the intermediate layer 41. Here, the uneven shape 4 of the stamper 40 for the first optical recording layer is formed on the surface of the intermediate layer 41.
An uneven shape 41 'is formed corresponding to 0'.

In the above spin coating and laminating steps, the ultraviolet curable resin 41a is supplied to the central portion of the stamper 40 for the first optical recording layer, the disc substrate 42 is placed on top of it, and the disc is spun. Board 42
Alternatively, the ultraviolet curable resin 41a may be spread over the gap between the first optical recording layer stamper 40 and the ultraviolet curable resin 41a is solidified by irradiating a sufficient amount of ultraviolet rays to form the intermediate layer 41.

Next, as shown in FIG. 15A, by peeling at the interface between the first optical recording layer stamper 40 and the intermediate layer 41, the concave-convex shape 41 ′ is transferred to the surface of the intermediate layer 41.

Next, as shown in FIG. 15 (b), a gas such as air or nitrogen gas is blown onto the surface of the intermediate layer 41 on which the irregular shapes 41 'are formed to remove dust, and then, for example, by a sputtering method or the like. A recording film such as a total reflection film, a dielectric film, a phase change film, and a dielectric film are laminated in this order,
The first optical recording layer 43 is formed. The layer structure and the number of layers differ depending on the type and design of the recording material. Playback only (ROM)
In the case of a type optical disc, aluminum is deposited to form the first optical recording layer having total reflection.

Next, an appropriate amount of ultraviolet curable resin to be an intermediate layer is supplied to the central portion of the stamper for the second optical recording layer, spin coating is performed, and the disk substrate 42 is bonded from the first optical recording layer 43 side, Irradiating a sufficient amount of ultraviolet rays to solidify the ultraviolet curable resin to form the intermediate layer 44, and transfer the uneven shape 44 ′ to the surface of the intermediate layer 44 to obtain the uneven shape 44 ′ of the intermediate layer 44.
The semi-transparent second optical recording layer 45 is formed on the formation surface. Next, the center hole CH is formed, and if necessary, the outer peripheral portion is trimmed to have an appropriate size to obtain the configuration shown in FIG.

Next, the pressure-sensitive adhesive sheet is attached to the bonding layer 4
As shown in FIG. 6, a substantially circular sheet-shaped substrate (second substrate) 47 having a center hole in the sheet center is attached to the second optical recording layer 45, and the optical disc having the configuration shown in FIG. You can

According to the above-described optical disc manufacturing method of the present embodiment, when the resin material to be the intermediate layer 41 is spin-coated on the stamper 40 which does not have a center hole in the center and has an uneven surface. Further, the resin can be supplied to the central portion of the stamper 40. Therefore, the intermediate layer 4
The resin material serving as No. 1 can be applied while suppressing unevenness in thickness, and in particular, even when the resin layer serving as an intermediate layer is formed thick so as to fill sputter flakes, unevenness in thickness can be suppressed.

Fifth Embodiment The optical disk according to the present embodiment has substantially the same structure as the optical disk according to the first embodiment, but has a single optical recording layer. The method for manufacturing the optical disc according to the present embodiment will be described below.

First, as shown in FIG. 17A, the stamper for the optical recording layer is installed so as to face the inside of the cavity of the mold, and the center hole CH is formed at the center by injection molding, for example, injecting molten polycarbonate. A disk substrate (first substrate) 50 having a substantially disk shape having a concave and convex shape 50 ′ for an optical recording layer is formed on the surface.

Next, as shown in FIG. 17B, a gas such as air or nitrogen gas is blown onto the surface of the disk substrate 50 on which the concavo-convex shape 50 'is formed to remove dust, and then, for example, by a sputtering method or the like. Total reflection film, dielectric film,
A recording film such as a phase change film and a dielectric film are laminated in this order to form the optical recording layer 51. The layer structure and the number of layers differ depending on the type and design of the recording material. Playback only (RO
In the case of the M) type optical disc, aluminum is deposited to form a total reflection type optical recording layer.

Next, as shown in FIG. 18A, a substantially circular sheet-like substrate (second substrate) 52 having a center hole with a thickness of preferably 100 μm or less, for example 80 μm, has a flat surface. Rotary table R that can be driven to rotate by
Stick it to T. The method of adhesion may be, for example, vacuum suction, sticking to the stage via a slightly adhesive sheet, or applying static electricity to the stage. Next, an appropriate amount of ultraviolet curable resin 53a, which serves as an intermediate layer, is supplied to the central portion of the sheet-like substrate 52 and spin coated.

Next, as shown in FIG. 18B, the disk substrate 50 is attached to the ultraviolet curable resin 53a from the side of the optical recording layer 51, and a sufficient amount of ultraviolet rays is irradiated to the ultraviolet curable resin 53a. Is solidified to form the intermediate layer 53.

In the above spin coating and laminating steps, the ultraviolet curable resin 53a is supplied to the central portion of the sheet-like substrate 52, and the disc substrate 50 is arranged above the optical recording layer 51 side as the lower surface. The UV curable resin 53a may be spread in the gap between the sheet-like substrate 52 and the optical recording layer 51 by spinning, and the UV curable resin 53a may be solidified by irradiating a sufficient amount of UV rays to form the intermediate layer 53. .

Next, the sheet substrate 52 and the intermediate layer 53.
By forming the center hole CH in the optical disc, the optical disc having the structure shown in FIG. 19 can be manufactured.

According to the method of manufacturing an optical disk in the present embodiment, when a resin material to be the intermediate layer 53 is spin-coated on one surface of the sheet-shaped substrate (second substrate) 52, a substantially circular sheet is formed. The resin can be supplied to the central portion of the substrate 52. Therefore, it is possible to apply the resin material serving as the intermediate layer 53 while suppressing unevenness in thickness, and in particular, even if the resin layer serving as the intermediate layer is formed thick so as to fill the sputter flakes, unevenness in thickness can be suppressed. .

In this embodiment, the optical recording layer 51 is used.
Instead of sticking the sheet-like substrate 52 to the sheet-like substrate, a sheet-like substrate on which one or more optical recording layers are previously formed can be stuck together, and a multilayer optical disc can be easily manufactured by this method. The sheet-shaped substrate on which one or more optical recording layers are formed in advance can be formed in the same manner as in the first or second embodiment.

Sixth Embodiment The optical disc according to the present embodiment has substantially the same structure as the optical disc according to the first embodiment, but has a single optical recording layer.

FIG. 20A is a schematic configuration diagram of an injection molding apparatus used for injection molding the disc substrate of the optical disc according to the present embodiment, and FIGS. 20B and 20C.
6A and 6B are enlarged views of the cavity C portion, showing a process of opening the core M3 and a process of closing the core M3, respectively. The mold of the injection molding device has a first mold M1 and a second mold M2, and is provided with a communicating space which is a sprue S, a runner R, and a cavity C. Although not shown, 1
Alternatively, one sprue may be connected to a plurality of cavities. Furthermore, the core M3 is placed at the position that will be the center hole.
Are arranged to control the shape of the center hole portion of the cavity C. As shown in FIG. 20 (b), resin is injected into the cavity with the core M3 open, and thereafter, as shown in FIG. 20 (c), the core M3
By closing, the center hole portion A of the cavity C can be thinned. A stamper having an uneven shape is installed on the side surface of the cavity C, and the surface of the thinned portion on the uneven surface forming surface is made flat.

The method of manufacturing the optical disc according to this embodiment will be described below. First, using the injection molding apparatus described above, a disk substrate 60 having a substantially disc shape and having an uneven shape 60 'for an optical recording layer formed on the surface is formed.
As shown in FIG. 21A, the obtained disk substrate 60 is thinned at the position A which becomes the center hole CH, and the center hole can be easily punched. Further, the surface of the thinned portion on the side where the uneven shape 60 'is formed is flat.

Next, as shown in FIG. 21 (b), a gas such as air or nitrogen gas is blown onto the surface of the disk substrate 60 on which the concavo-convex shape 60 'is formed to remove dust, and then, for example, by a sputtering method or the like. Total reflection film, dielectric film,
A recording film such as a phase change film and a dielectric film are laminated in this order to form an optical recording layer 61. The layer structure and the number of layers differ depending on the type and design of the recording material. Playback only (RO
In the case of the M) type optical disc, aluminum is deposited to form a total reflection type optical recording layer.

Next, as shown in FIG. 22 (a), the disk substrate 60 is placed on a rotary table RT which can be driven to rotate, and an appropriate amount of ultraviolet rays to be a protective layer in the central portion of the disk substrate 60 is cured. The resin 62a is supplied and spin coating is performed.

Next, as shown in FIG. 22B, the flattened ultraviolet curable resin 62a is irradiated with a sufficient amount of ultraviolet rays to be solidified to form a protective layer 62.

Next, the thinned portion (position A) of the disk substrate 60 which becomes the center hole CH is punched to form the center hole CH, and the optical disk having the structure shown in FIG. 23 can be manufactured.

According to the optical disc manufacturing method of the present embodiment, the protective layer 6 is formed on one surface of the disc substrate 60.
When the resin material to be 2 is spin-coated, the portion of the disk substrate 60 that becomes the center hole CH is thinned,
Since it is flattened, the resin can be supplied to the central portion of the disk substrate 60. Therefore, the resin material that becomes the protective layer 62 can be applied while suppressing unevenness in thickness, and even if the resin layer that becomes an intermediate layer is formed thick so as to bury sputter flakes, uneven thickness can be suppressed and formed. .

Seventh Embodiment The optical disk according to the present embodiment has substantially the same structure as the optical disk according to the fifth embodiment, but has an optical recording layer having a two-layer structure. The method for manufacturing the optical disc according to the present embodiment will be described below.

First, similarly to the sixth embodiment, the disk substrate 70 having a thin surface and a flat surface is formed at the position A which becomes the center hole CH, and the surface on which the concave-convex shape 70 ′ of the disk substrate 70 is formed. Then, the first optical recording layer 71 is formed. Next, an appropriate amount of ultraviolet curable resin to be an intermediate layer is supplied to the central portion of the disc substrate 70, and spin coating is performed. On the other hand, the uneven shape 7 is formed on the surface of the intermediate layer of the protective layer 74 including the sheet-shaped substrate and the intermediate layer on the ultraviolet curable resin.
4'is transferred, and a second optical recording layer 73 is formed on top of it, and the second optical recording layer 73 is attached to the UV-curable resin spin-coated as described above and irradiated with a sufficient amount of ultraviolet rays. The intermediate layer 72 is solidified to have the structure shown in FIG. Here, the step of transferring the concave-convex shape 74 ′ to the surface of the intermediate layer of the protective layer 74 including the sheet-shaped substrate and the intermediate layer and forming the second optical recording layer 73 on the upper layer is the same as in the first embodiment or the second embodiment. It can be performed by the method described in the embodiment.

Next, the thinned portion (position A) of the disk substrate 70 to be the center hole CH is punched to form the center hole CH, and the optical disk having the structure shown in FIG. 25 can be manufactured.

According to the method of manufacturing an optical disk in the present embodiment, the intermediate layer 7 is formed on one surface of the disk substrate 70.
When the resin material to be 2 is spin-coated, the portion of the disk substrate 70 that will be the center hole CH is thinned,
Since it is flattened, the resin can be supplied to the central portion of the disk substrate 70. Therefore, the resin material for the intermediate layer 72 can be applied while suppressing the thickness unevenness, and the thickness unevenness can be suppressed even when the resin layer serving as the intermediate layer is formed thick so as to fill the sputter flakes. .

The present invention is not limited to the above embodiment. For example, in each embodiment, by repeating the process of forming an intermediate layer on the upper layer of the optical recording layer, transferring the uneven shape, and forming the optical recording layer on the obtained uneven shape forming surface, It is possible to manufacture an optical disc having an optical recording layer of the number of layers. Further, the layer structure of the optical recording film is not limited to the structure described in the embodiment, but may be various structures according to the material of the recording film and the like. The optical recording film may have three or more layers. Further, in addition to the phase change type optical recording medium, it is also applicable to a magneto-optical recording medium and an optical disc medium using an organic dye material. It is also possible to use a spin coating method. Further, the present invention can be applied to a ROM type optical disc in which a reflection film such as aluminum is provided on the uneven shape which becomes the information pit. In addition, various modifications can be made without changing the gist of the present invention.

[0115]

According to the method for producing an optical recording medium of the present invention, it is possible to suppress unevenness in thickness when spin coating a resin material constituting an intermediate layer or the like, and in particular, even if sputter flakes are present, uneven thickness can be suppressed. Can be suppressed.

[Brief description of drawings]

FIG. 1A is a schematic perspective view showing a state of light irradiation of an optical disc according to a first embodiment of the present invention.
(B) is a schematic cross section.

FIGS. 2A to 2C are cross-sectional views showing a manufacturing process of an optical disk manufacturing method according to the first embodiment.

3 (a) to 3 (c) are cross-sectional views showing a step that follows FIG.

4A and 4B are cross-sectional views showing a step that follows the step of FIG.

5A to 5C are cross-sectional views showing a manufacturing process of an optical disk manufacturing method according to a second embodiment.

6A to 6C are cross-sectional views showing a step that follows the step of FIG.

FIGS. 7A and 7B are cross-sectional views showing a step that follows FIG.

8A and 8B are cross-sectional views showing a step that follows FIG. 7.

9A and 9B are cross-sectional views showing the manufacturing process of the optical disc manufacturing method according to the third embodiment.

10A and 10B are cross-sectional views showing a step that follows FIG.

11A and 11B are cross-sectional views showing a step that follows FIG. 10.

12A and 12B are cross-sectional views showing a step that follows FIG. 11.

13A and 13B are cross-sectional views showing a step that follows FIG. 12.

FIGS. 14A and 14B are cross-sectional views showing the manufacturing steps of the optical disk manufacturing method according to the fourth embodiment.

15 (a) and 15 (b) are cross-sectional views showing a step that follows FIG.

16A and 16B are cross-sectional views showing a step that follows the step of FIG.

17 (a) and 17 (b) are cross-sectional views showing a manufacturing process of an optical disk manufacturing method according to a fifth embodiment.

FIG. 18A and FIG. 18B are cross-sectional views showing a step that follows FIG.

FIG. 19 is a cross-sectional view showing a step that follows FIG. 18.

FIG. 20 is a schematic diagram showing a configuration of an injection molding device according to a sixth embodiment.

21A and 21B are cross-sectional views showing the manufacturing process of the optical disc manufacturing method according to the sixth embodiment.

22A and 22B are cross-sectional views showing a step that follows FIG. 21.

23 is a cross-sectional view showing a step that follows FIG. 22. FIG.

FIG. 24 is a cross-sectional view showing the manufacturing process of the optical disc manufacturing method according to the seventh embodiment.

25 is a cross-sectional view showing a step that follows FIG. 24. FIG.

FIG. 26 (a) is a schematic perspective view showing how a conventional optical disc is irradiated with light, and FIG. 26 (b) is a schematic sectional view.

FIG. 27 is a schematic view showing a problem of the method for manufacturing the optical disc according to the conventional example.

[Explanation of symbols]

Reference numeral 10 ... Second optical recording layer stamper, 11 ... Second optical recording layer resin stamper, 12 ... Second optical recording layer, 13 ... Sheet substrate, 14 ... Intermediate layer, 14a ... UV curable resin,
15 ... Disk substrate, 16 ... First optical recording layer, 17 ... Intermediate layer, 17a ... Pressure sensitive adhesive sheet, 18 ... Protective layer, 20
... Sheet-shaped substrate (second substrate), 21 ... Intermediate layer, 21a ...
UV curing resin, 22 ... Glass stamper for third optical recording layer, 23 ... Third optical recording layer, 24 ... Intermediate layer, 24a ...
UV curable resin, 25 ... Glass stamper for second optical recording layer, 26 ... Second optical recording layer, 27 ... Disk substrate, 2
8 ... First optical recording layer, 29 ... Intermediate layer, 29a ... Pressure-sensitive adhesive sheet, 30 ... Stamper for third optical recording layer, 31 ... Intermediate layer, 31a ... UV curable resin, 32 ... Sheet substrate,
33 ... Third optical recording layer, 34 ... Stamper for second optical recording layer, 35 ... Intermediate layer, 35a ... UV curable resin, 36 ... Second optical recording layer, 37 ... Disk substrate, 38 ... First optical recording layer, 39 ... Intermediate layer, 39a ... Pressure-sensitive adhesive sheet, 40
... stamper for first optical recording layer 41, intermediate layer 41a ...
UV curing resin, 42 ... Disk substrate, 43 ... First optical recording layer, 44 ... Intermediate layer, 45 ... Second optical recording layer, 46 ...
Lamination layer, 47 ... Sheet substrate, 50 ... Disc substrate, 51 ... Optical recording layer, 52 ... Sheet substrate, 53 ... Intermediate layer, 53a ... UV curable resin, 60 ... Disc substrate,
61 ... Optical recording layer, 62 ... Protective layer, 62a ... UV curable resin, 70 ... Disk substrate, 71 ... First optical recording layer, 7
2 ... Intermediate layer, 73 ... Second optical recording layer, 74 ... Protective layer, 1
00 ... Disk substrate, 101 ... First optical recording layer, 102
... intermediate layer, 102a ... UV curable resin, 103 ... second optical recording layer, 104 ... intermediate layer, 105 ... protective sheet, 10
6 ... Protective layer, 10 ', 11', 14 ', 15', 2
1 ', 22', 24 ', 25', 27 ', 30', 3
1 ', 34', 35 ', 37', 40 ', 41', 4
4 ', 50', 60 ', 70', 72 ', 74', 10
0 ', 103', 104 '... Rough shape, C ... Cavity, CH ... Center hole, DC ... Optical disk, DR ... Drive direction, LT ... Optical, M1 ... First mold, M2 ... Second mold, M3 ... Core, OL ... Objective lens, R ... Runner, R
T ... rotary table, S ... sprue.

Continued front page    (72) Inventor Shinsuke Kishi             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Jun Nakano             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation F-term (reference) 5D121 AA01 AA04 AA07 CA06 CA07                       EE22 EE23 EE26 EE27 EE28                       FF01 FF13 GG02 GG24

Claims (20)

[Claims] 1. A method of manufacturing an optical recording medium having a center hole in the center and having at least two optical recording layers, the method having a substantially disk shape having a center hole in the center. A step of forming a first substrate having a concavo-convex shape on its surface, a step of forming a first optical recording layer on the concavo-convex shape forming surface of the medium substrate, and a substantially circular sheet-like first step having no center hole in the center. 2 a step of transferring the concavo-convex shape to one surface of the second substrate to form a second optical recording layer on the concavo-convex shape forming surface of the second substrate, and a step of opening a center hole in the center of the second substrate, A method of manufacturing an optical recording medium, comprising a step of bonding the first optical recording layer side of the first substrate and the second optical recording layer side of the second substrate with a bonding layer. 2. A concavo-convex shape is transferred onto one surface of a substantially circular sheet-shaped second substrate having no center hole at the center thereof, and a second optical recording layer is formed on the concavo-convex shape forming surface of the second substrate. The step of forming is a stamper in which an intermediate layer material is supplied onto one surface of the second substrate and spin coated to have an uneven shape, and the second optical recording layer is formed on the uneven surface. And a step of solidifying the intermediate layer material to form an intermediate layer, and peeling at the interface between the second optical recording layer and the stamper,
The method for producing an optical recording medium according to claim 1, further comprising the step of transferring the uneven shape to the intermediate layer and transferring the second optical recording layer onto the intermediate layer. 3. The method for manufacturing an optical recording medium according to claim 2, wherein the stamper is a resin stamper. 4. A concavo-convex shape is transferred onto one surface of a substantially circular sheet-shaped second substrate having no center hole in the center, and a second optical recording layer is formed on the concavo-convex shape forming surface of the second substrate. In the forming step, an intermediate layer material is supplied onto one surface of the second substrate, spin coating is performed, the material is bonded to a stamper having an uneven shape, and the intermediate layer material is solidified to form an intermediate layer. A step of peeling at the interface between the intermediate layer and the stamper to transfer the uneven shape to the intermediate layer, and a step of forming a second optical recording layer on the uneven surface of the intermediate layer. The method for manufacturing the optical recording medium according to claim 1. 5. The method for manufacturing an optical recording medium according to claim 4, wherein the stamper is a glass stamper. 6. A concavo-convex shape is transferred onto one surface of a substantially circular sheet-shaped second substrate having no center hole in the center, and a second optical recording layer is formed on the concavo-convex shape forming surface of the second substrate. The forming step is performed by supplying the intermediate layer material onto a stamper having no center hole in the center and having an uneven shape on the surface, and by spin-coating, bonding the intermediate layer material to one surface of the second substrate, A step of solidifying a layer material to form an intermediate layer, a step of peeling the layer material at an interface between the intermediate layer and the stamper, and a step of forming a second optical recording layer on the uneven surface of the intermediate layer. Item 2. A method for manufacturing an optical recording medium according to item 1. 7. The method for manufacturing an optical recording medium according to claim 6, wherein the stamper is a metal stamper. 8. An uneven shape is transferred to one surface of a substantially circular sheet-shaped second substrate having no center hole in the center, and a second optical recording layer is formed on the uneven surface of the second substrate. The step of forming an intermediate layer on the upper layer of the second optical recording layer to transfer the uneven shape after the forming step and forming the optical recording layer on the uneven shape forming surface is repeated at least once.
A method for manufacturing the optical recording medium according to. 9. A method for producing an optical recording medium having a substantially disc shape having a center hole in the center and having at least one optical recording layer, the method having no center hole in the center and an uneven surface. The intermediate layer material is supplied onto the stamper having the above, and is bonded to one surface of the substantially disk-shaped medium substrate by spin coating, and the intermediate layer material is solidified to form the intermediate layer. The step of transferring the uneven shape to the surface of the medium substrate, the step of forming an optical recording layer on the uneven surface of the medium substrate, the step of opening a center hole at least in the center of the optical recording layer, the optical recording layer And a step of forming a protective layer thereon. 10. An intermediate layer material is supplied onto a stamper having no center hole in the center and having an uneven shape on the surface,
In the step of bonding by spin coating to one surface of the substantially disk-shaped medium substrate, solidifying the intermediate layer material to form an intermediate layer, and transferring the uneven shape to the one surface of the medium substrate, In the step of adhering a medium substrate having no center hole in the center with the intermediate layer material spin-coated on the stamper and opening the center hole at least in the center of the optical recording layer, the medium substrate, the intermediate The method of manufacturing an optical recording medium according to claim 9, wherein a center hole is opened in the center of the layer and the optical recording layer. 11. The method of manufacturing an optical recording medium according to claim 9, wherein the stamper is a metal stamper. 12. After the step of forming an optical recording layer on the uneven surface of the medium substrate, an intermediate layer is formed on the optical recording layer to transfer the uneven shape, and the uneven surface is formed. The method for producing an optical recording medium according to claim 9, wherein the step of forming the optical recording layer on the substrate is repeated at least once. 13. A method of manufacturing an optical recording medium having a center hole in the center and having at least one optical recording layer, the method having a substantially disk shape having a center hole in the center. A step of forming a first substrate having an uneven surface on the surface, a step of forming an optical recording layer on the uneven surface of the first substrate, and a center centered on the optical recording layer side of the first substrate. A method for manufacturing an optical recording medium, which comprises a step of attaching a substantially circular sheet-shaped second substrate having no holes with an attachment layer, and a step of opening a center hole in the center of the second substrate. 14. The step of bonding a substantially circular sheet-shaped second substrate having no center hole at the center thereof to the optical recording layer side of the first substrate is carried out on one surface of the second substrate. 14. The optical according to claim 13, further comprising the steps of supplying a bonding layer material, bonding the bonding layer material to the optical recording layer side of the first substrate by spin coating, and solidifying the bonding layer material to form a bonding layer. Recording medium manufacturing method. 15. The step of bonding the second substrate to the optical recording layer side of the first substrate before bonding the substantially circular sheet-shaped second substrate having no center hole in the center with a bonding layer. A step of forming an intermediate layer on one surface to transfer the uneven shape and forming an optical recording layer on the uneven surface is performed at least once, and the optical recording layer side of the first substrate is centered. In the step of bonding the substantially circular sheet-shaped second substrate having no center hole with the bonding layer, the optical recording layer side of the first substrate and the optical recording layer side of the second substrate are bonded together. The method for manufacturing the optical recording medium according to claim 13. 16. A method of manufacturing an optical recording medium having a substantially disc shape having a center hole in the center and having at least one optical recording layer, wherein one surface has a concavo-convex shape, and the center hole has a center. A step of forming a substantially disc-shaped medium substrate in which the portion to be thinned is thinner than other portions, and the surface of the thinned portion on the side of the uneven shape forming surface is flat; A step of forming an optical recording layer on the surface of the medium substrate on which irregularities are formed, a step of forming a protective layer on the optical recording layer, and a center hole is formed by opening a thinned portion in the center of the medium substrate. A method of manufacturing an optical recording medium, which comprises a step of forming. 17. The step of forming the protective layer comprises the steps of supplying a protective layer material onto the optical recording layer of the medium substrate by spin coating and solidifying the protective layer material to form a protective layer. The method of manufacturing an optical recording medium according to claim 16, which comprises. 18. The step of forming the protective layer comprises supplying a bonding layer material constituting the protective layer on the optical recording layer of the medium substrate, and spin coating to form a substantially circular shape having no center hole in the center. The method of manufacturing an optical recording medium according to claim 16, comprising a step of bonding the sheet substrate and the step of solidifying the bonding layer material to form a protective layer. 19. A method of manufacturing an optical recording medium having a substantially disc shape having a center hole in the center and having at least two optical recording layers, wherein one surface has a concavo-convex shape, and the center hole has a center. Forming a substantially disk-shaped first substrate in which the portion to be formed is thinner than other portions, and the surface of the thinned portion on the side of the uneven shape forming surface is flat; A step of forming a first optical recording layer on the uneven surface of the first substrate, and transferring the uneven shape to one surface of a substantially circular sheet-like second substrate having no center hole in the center, A step of forming a second optical recording layer on the surface of the second substrate on which irregularities are formed, and bonding the first optical recording layer side of the first substrate and the second optical recording layer side of the second substrate to each other. The step of laminating with the layers and the center of the first substrate Method of producing an optical recording medium and a step of forming a Nikuka portion with open center hole. 20. The step of bonding the first optical recording layer side of the first substrate and the second optical recording layer side of the second substrate with a bonding layer comprises the first optical recording of the first substrate. 20. A step of supplying a bonding layer material onto a layer and bonding the same to the second optical recording layer side of the second substrate by spin coating, and a step of solidifying the bonding layer material. Manufacturing method of optical recording medium.