JP2009020975A - Multilayer optical recording medium and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a resin remains on a transparent stamper, when the transparent stamper is to be peeled from the resin. <P>SOLUTION: The present invention relates to the manufacturing method of a multilayer optical recording medium, in which an information pattern is transferred to the transparent resin film by pressing the transparent stamper having a center hole, wherein a film thickness of an outer edge part of a substrate of the transparent resin film is thicker than the film thickness in the vicinity of the center hole of the substrate, and the transparent stamper presses the outer edge part of the substrate of the transparent resin film; and the energy for curing the transparent resin film is supplied, in a state of not pressing the transparent resin film in the vicinity of the center hole of the substrate, then the transparent stamper is pressed to the transparent resin, while the energy is supplied, to cure the transparent resin film, and the stamper is peeled from an end part side of the center hole of the transparent substrate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical recording medium and a manufacturing method thereof, and more particularly to a multilayer optical recording medium having a plurality of information recording layers and a manufacturing method thereof.

  In recent years, optical recording media are being applied as recording media for recording various types of information in fields such as computers and audio visuals. Furthermore, with the spread of mobile computers and the diversification of information, small and large capacity optical recording media are required.

  As a method of increasing the capacity, there are a method of miniaturizing an information pattern to be recorded and a method of multilayering a recording layer. In optical recording media, the information pattern is usually miniaturized, and then the capacity is increased by multilayering the recording layer.

  This is called a photopolymerization method (hereinafter referred to as 2P method) in which an intermediate resin layer is provided on a substrate on which a recording layer is formed and a transparent stamper is pressed on the intermediate resin layer to form an information pattern. There is a manufacturing method.

  When the 2P method is used, there is a problem in peelability between a polycarbonate transparent stamper (hereinafter abbreviated as a PC stamper) and an ultraviolet curable resin called a 2P resin (Photo Polymer) used as an intermediate resin layer.

As a solution to this problem, Patent Document 1 discloses an example in which a film for improving the peelability to 2P resin is provided on a PC stamper, and a material such as polyolefin having good peelability to 2P resin is used as a transparent stamper. Is disclosed.
JP 2005-166241 A

  However, when the intermediate layer is formed on a resin-made transparent stamper that is made disposable, an extra step is required for manufacturing the transparent stamper. In addition, if a material such as polyolefin is used, extra management costs are incurred because the substrate and transparent stamper materials are different, and the cost increases because the disposable transparent stamper material is more expensive than the substrate material. Problems occur.

An optical recording medium manufacturing method for solving the above problems includes a step of forming a transparent resin film on a first substrate having a center hole, and pressing the second substrate having a center hole against the transparent resin film. A multi-layer light including a step, a step of supplying energy for curing the transparent resin film to the transparent resin film, and a step of curing the transparent resin film; and a step of peeling the second substrate from the transparent resin film. A method of manufacturing a recording medium,
The film thickness of the outer edge of the first substrate of the transparent resin film is thicker than the film thickness in the vicinity of the center hole of the first substrate, and the inner peripheral edge of the transparent resin film is the radius of the inner peripheral edge of the transparent resin. When the position is a on the first substrate side and b on the second substrate side, pressing is performed in a state where a <b, and then energy for curing the transparent resin film is supplied, and the first substrate is supplied. A method for producing a multilayer optical recording medium, comprising peeling off the second substrate from the end side of the central hole.

  Furthermore, in the multilayer optical recording medium of the present invention, the information pattern of the transparent resin film is formed on the inner peripheral end of the transparent resin film formed on the substrate having the center hole and transferred with the information pattern. The multilayer optical recording medium is characterized in that the radius position b of the end portion on the side and the radius position a on the side opposite to the side where the information pattern is formed satisfy a <b.

  By employing the multilayer optical recording medium manufacturing method of the present invention, an inexpensive PC stamper can be peeled off, and an optical recording medium having a plurality of recording layers can be supplied with a high yield.

  The inventor uses the 2P method to solve the problem when peeling the transparent stamper after transferring the signal pattern in the method of manufacturing a multilayer optical recording medium in which the signal pattern formed on the transparent stamper is transferred to the 2P resin. We studied how to do it.

The inventor has confirmed that the transparent resin (2P resin) film formed on the first substrate is thicker at the outer edge of the first substrate than at the center hole of the first substrate. I found it. If you have such a film thickness distribution,
When the inner peripheral edge of the transparent resin film is a <b, where the radial position of the inner peripheral edge of the transparent resin is a on the first substrate side and b on the second substrate side, the pressing is performed. And
After that, supplying energy to cure the transparent resin, after curing the transparent resin,
It has been found that the releasability between the second substrate and the transparent resin film can be improved by peeling the second substrate from the end of the center hole of the first substrate.

  In other words, the present invention maintains the state in which the shape of the transparent resin opening side end is maintained in the state where the transparent resin film is formed after the pressing is completed, and then supplies energy for curing the transparent resin. To do.

  In this case, when the contact angle with respect to the surface on the first substrate side is c and the contact angle with respect to the second substrate is d, c <d.

  It has been found that the peelability between the second substrate and the transparent resin film can be improved when the shape of the end of the transparent resin on the opening side at the time of peeling is the above-mentioned shape.

  That is, the transparent resin film for curing the transparent resin has a <b when the radial position of the inner peripheral side end portion of the transparent resin is a on the first substrate side and b on the second substrate side. . Further, when the contact angle with respect to the surface on the first substrate side is c and the contact angle with respect to the second substrate is d at the inner peripheral end of the transparent resin, c <d. Even after curing, the above shape is maintained.

  The first substrate may be a resin transparent substrate and the second substrate may be a transparent stamper, or the first substrate may be a resin transparent substrate and the second substrate may be a glass substrate.

  Further, when the second substrate is a transparent stamper, the above-described pressing corresponds to pressing and transferring a signal pattern provided on the transparent stamper.

  The curing of the transparent resin is performed by applying energy for curing the transparent resin. Heat is applied (irradiated) when the transparent resin is a thermosetting resin, and ultraviolet light is applied when the transparent resin is an ultraviolet curable resin.

  In addition, the transparent resin film formed on the substrate having the center hole and transferred with the information pattern has a radial position b at the inner peripheral end of the transparent resin film and the end of the transparent resin film on which the information pattern is formed. The multilayer optical recording medium is characterized in that the radius position a on the side facing the information pattern is a <b.

  The present invention will be described in detail below with reference to the drawings.

  FIG. 13 is a process sectional view showing the manufacturing process of the present invention.

  A transparent resin film 03 made of an ultraviolet curable resin serving as an intermediate layer is formed on a substrate 02 having a central hole on which a recording layer is formed by using a spin coating method. The transparent resin film 03 drops the transparent resin outside the center hole of the substrate and outside the region where the recording layer is formed, and then rotates the substrate to form the transparent resin film 03 (see FIG. 13A). ).

  Alternatively, the transparent resin may be dropped at a low rotation speed of about 100 rotations, and then the transparent resin film 03 may be formed using a high speed rotation speed of about 1000 to 5000 rotations.

  When the doughnut-shaped transparent resin film 03 is formed on the substrate by using the spin coating method, the transparent resin film 03 is thicker on the outer peripheral side of the substrate than the uniform film thickness in the central portion. It is known that the film thickness on the center hole side is reduced.

  At this time, as shown in the enlarged view of FIG. 13 (5), the shape of the end portion on the center hole side of the transparent resin film 03 is the inner portion due to the wettability between the substrate 02 and the transparent resin at the place where it contacts the substrate 02. A wall is formed toward the outer peripheral side and toward the outer peripheral side. The film thickness at the top of the wall is thinner than the average film thickness at the center of the substrate 02 and thicker toward the center.

  In this state, when the transparent stamper 01 is pressed against the transparent resin film 03, first, it comes into contact with the thick part around the outside of the substrate (see FIG. 13 (2)). In this state, when the transparent stamper 01 is further pressed, the transparent resin on the outer peripheral side of the substrate moves toward the inner peripheral side of the substrate and presses the region having a uniform film thickness.

  Conventionally, the transparent stamper 01 is further pressed. Since the total volume of the transparent resin does not change, the inner peripheral wall of the transparent resin has a shape swelled toward the inner periphery. In the present invention, the transparent stamper 01 is pressed against the inner peripheral side of the transparent resin film. The end ends in a state where the shape at the time of application is maintained (see FIG. 13 (3)).

  Thereafter, the transparent resin film 03 is cured by irradiating with ultraviolet rays (see FIG. 13 (3)).

  FIG. 2 shows an enlarged view of the transparent resin film 03 in a state where the contact between the transparent stamper 01 and the transparent resin film 03 is completed. As shown in FIG. 2, the transparent stamper 01 is pressed against the transparent resin film 03 formed on the substrate 02 (recording layer is not shown), and an information pattern (not shown) formed on the transparent stamper 01 is formed. Transferred to the transparent resin film 03. The wavy line at the left end in FIG. 2 indicates the center line of the substrate 02 and the stamper 01.

In the present invention, the shape of the end portion on the inner peripheral side of the substrate 02 of the transparent resin film 03 is
1. The position a of the end of the transparent resin film 03 in contact with the substrate 02 from the center of the substrate (hereinafter referred to as the substrate side inner peripheral edge radius position a) and the side of the transparent resin film 03 in contact with the transparent stamper 01 The position b of the end from the center of the substrate (hereinafter referred to as stamper side inner peripheral edge radius position b) is a <b,
2. As shown in FIG. 3, a contact angle c between the transparent resin 03 and the substrate 02 (referred to as a substrate side contact angle c) and a contact angle d between the transparent resin 03 and the transparent stamper 01 (hereinafter referred to as a stamper side contact angle d) C <d,
In this state, the pressing of the stamper is finished.

  Next, a process of peeling the transparent stamper 01 from the transparent resin film 03 after the transparent resin film is cured will be described with reference to FIG. A transparent stamper 01 is placed on the stage 07. The substrate 02 has a transparent resin film 03 formed on one surface, and is disposed so that the transparent resin film and the transparent stamper 01 face each other. The wavy line in the figure is the center line of the substrate 02, the stage 07 and the transparent stamper 01, and the substrate 02, the stage 07 and the transparent stamper 01 are aligned so that their centers coincide (FIG. 4A). reference).

  After the information pattern provided on the transparent stamper 01 is transferred to the transparent resin film 03 and the transparent resin film 03 is cured by the manufacturing method described above, the substrate 02 is used from the inner peripheral side end side of the substrate 02 using the center member 06. A pressure is applied to the transparent stamper 01 to peel off the transparent resin film 03 (see FIG. 4B).

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

Example 1
A first embodiment of the method for producing a two-layer optical recording medium according to the present invention will be described with reference to FIGS. FIG. 1 shows one half of a rotationally symmetric disk-shaped cross-sectional view having a center hole, and the center holes of the substrate and stamper are omitted. The broken lines in FIGS. 4 and 5 indicate the center line of the disk-shaped cross-sectional view. This is one example, and the present invention can be applied to an optical recording medium having two or more layers. The present invention is not limited to this configuration.

  As shown in FIG. 1 (1), a polycarbonate resin is first injection-molded (not shown) as a substrate to form a pit row corresponding to the first reflecting surface 11 on one side. A substrate 02 having a thickness of 15 mm and a thickness of 1.1 mm was obtained. Here, pit rows having a track pitch of 0.32 μm are formed on the first reflecting surface 11.

  Next, as shown in FIG. 1 (2), Al was deposited on the substrate 02 as the first reflective film 12. The film thickness was 50 nm.

  In this embodiment, a read-only (ROM) disk is assumed. However, a write-once type or a rewritable type may be used, and the concavo-convex pattern may be a land / groove, and is not limited to a bit string.

  As shown in FIG. 1 (3), a transparent resin was applied onto the substrate 02 by spin coating to form a transparent resin film 03. The rotation speed was 3000 rpm, and UV curable KDL117 manufactured by Nippon Kayaku Co., Ltd. was used as the transparent resin, so that the average film thickness was 25 μm. In this state, the outermost peripheral film thickness was 45 μm. Here, the average film thickness means the film thickness of a region having a constant film thickness at the center of the film.

  In the following description, when expressed as a uniform thickness (first constant thickness), the average film thickness means the film thickness of a region having a constant film thickness at the center of the film. This means that the outermost film thickness is thicker than the average film thickness.

  As a material of the transparent resin film 03, it is only necessary to transmit a laser when reading and writing as an optical disk. In addition to the ultraviolet curable resin described above, any curable resin such as a radiation curable resin or a thermosetting resin is used. be able to.

  Furthermore, as the transparent resin film 03, as shown in FIG. 5, the transparent resin may be applied and cured in a plurality of times. By doing so, it is possible to control TILT reduction due to curing shrinkage of the ultraviolet curable resin and peelability from the stamper.

  A transparent resin film 03 applied in two steps is shown in FIG. In the case of performing application in two steps, the transparent resin 03 was cured after completing the first application, and then the second application was performed. The process after application is the same as in the case of one application.

  In the case of applying twice, TILT due to curing shrinkage of the ultraviolet curable resin can be reduced as compared with the case of applying once. Furthermore, by performing the first application with a transparent resin having a good adhesion to the substrate and the first application with a transparent resin having a good releasability from the stamper, the releasability from the stamper can be controlled.

  As shown in FIG. 1 (4), the substrate 02 and the stamper 01 were bonded together in a vacuum chamber (not shown) while maintaining the shape at the time of application.

As a result,
1. As shown in FIG. 2, when the substrate side inner peripheral edge radius position 21 and the stamper side inner peripheral edge radius position 22 of the transparent resin 03 are a and b, respectively, a <b.
2. Further, as shown in FIG. 3, the contact angle c between the substrate 02 and the transparent resin 03 and the contact angle d between the stamper and the transparent resin were c <d.

  Thereafter, using a mercury lamp, ultraviolet rays of 800 mJ (integrated value) were irradiated to cure the ultraviolet curable resin.

  Next, as shown in FIG. 1 (5), the bonded substrate 02 and stamper 01 were peeled off. At that time, as shown in FIGS. 4A and 4B, the stamper 01 is fixed to the stage 07, and peeling is performed by abutting the central member 06 against the substrate 02 from the inside of the central hole of the stamper 01. It was.

  In this embodiment, the diameter of the central hole between the substrate and the stamper is set to substrate <stamper, but the present invention is not limited to this.

  As the substrate 02 and the stamper 01 base material, in addition to inexpensive PC materials, various durable resin materials, quartz glass, silicon wafers, and the like can be used, and stable stamper peeling can be performed. . In this example, a polycarbonate substrate having a thickness of 1.1 mm and an outer diameter of 120 mm, similar to the substrate, was used as the stamper.

  Next, as shown in FIG. 1 (6), a pit row corresponding to the second reflecting surface 13 corresponding to the stamper 01 is formed on the substrate 02 from which the stamper 01 has been peeled off. An Ag alloy was formed as the reflective film 14. The film thickness was 15 nm.

  Finally, the substrate 02 having the two recording surfaces is rotated at 90 rpm, an ultraviolet curable resin to be the cover layer 05 is dropped on the second reflective film 14, and spread by rotating at 500 rpm, It was cured by irradiation with ultraviolet rays (not shown). Further, a hard coat layer (not shown) was applied to obtain a two-layer optical recording medium.

  As a cover layer, after apply | coating curable resin, you may harden | cure, a sheet-like thing may be bonded together, and it is not limited to this.

  In the peeling of the stamper 01, the OK / NG ratio of the peeling was 98/100.

(Comparative example)
In the comparative example, similarly to Example 1, a disk was prepared through the steps of FIGS. The difference in the manufacturing method between the comparative example and Example 1 is the difference in timing for completing the bonding. In Example 1, the shape of the end portion on the inner peripheral side of the transparent resin film was completed while maintaining the shape at the time of application, and the film was cured by irradiation with ultraviolet rays.

  On the other hand, the comparative example is a pasting process in which a sufficient pressure is applied and pressed so that the transparent stamper 01 is in close contact with the transparent resin film, and the wall surface of the resin layer expands toward the inner peripheral side. After pasting together under the conditions, ultraviolet rays for curing the transparent resin film were irradiated from the transparent stamper side.

  The reason why the wall surface of the resin layer swells to the inner peripheral side is that a sufficient pressure is applied and the film thickness becomes slightly thinner than the film thickness in the state where the application has been completed, so that the excess resin is at the end on the inner peripheral side. It seems to be formed by concentrating on the wall and inflating the wall at the end.

  In the comparative example, as shown in FIG. 6, the inner peripheral edge radius position a on the transparent resin substrate 02 and the inner peripheral edge radius position b on the transparent stamper 01 are a = b, and the contact angle between the substrate and the transparent resin. The contact angle d between c and the stamper and the transparent resin was c = d.

  4 and 6 indicate the center line of the disk cross-sectional view.

  In the stamper peeling, the OK / NG ratio of peeling was 67/100.

(Example 2)
Example 2 of the method for producing a four-layer optical recording medium in the present invention will be described. This is one example, and the present invention can be applied to an optical recording medium having four or more layers. The present invention is not limited to this configuration.

Similarly to Example 1, after forming the second recording layer (see FIG. 1 (6)), the steps of FIGS. 1 (3) to (5) were repeated twice to obtain a four-layer optical recording medium. The thicknesses of the transparent resin film 03 were 17, 15, and 13 μm in this order, and the cover layer was 60 μm. A diagram of the resulting four-layer optical recording medium is shown in FIG. A TiO ₂ film was formed on the third reflecting surface 15 as a third reflecting film (not shown) and a fourth reflecting film 16 (not shown) on the fourth reflecting surface 16, and the thicknesses were 19 nm and 14 nm, respectively. It was.

  In peeling off the transparent stamper 01, the OK / NG rate of peeling was 98/100.

In the peeling of the stamper for producing the third reflecting surface, the OK / NG rate of peeling was 99/100.
In the peeling of the stamper for producing the fourth reflecting surface, the peeling OK / NG ratio was 98/100.

(Example 3)
Embodiment 3 of the method for manufacturing a four-layer optical recording medium in the present invention will be described. This is one example, and the present invention can be applied to an optical recording medium having four or more layers. The present invention is not limited to this configuration.

  An optical recording medium was obtained using the manufacturing method shown in FIG.

  In the present embodiment, similarly to the first embodiment, the transparent resin film comes into contact with the stamper from the outer peripheral side according to the film thickness distribution (thickness on the outer peripheral side) generated by spin coating, and the contact area with the stamper is When it spreads toward the center, the transparent resin film was cured by irradiating with ultraviolet rays 04.

  In FIG. 8A, a cover sheet 2p resin (photoreactive curable resin) for constituting a cover sheet (resin protective layer) provided on the L3 layer recording film on a glass substrate (transparent support substrate) 101. 102 is similarly applied. Typically, the glass substrate 101 has a thickness of 1 mm, a diameter of 120 mm, and a center hole diameter of 15 mm. The cover sheet 2p resin 102 is dropped in an annular shape on the inner peripheral side of the glass substrate 101 having a center hole (not shown), and the glass substrate is rotated and shaken to obtain a uniform thickness (first constant thickness). did. The average film thickness of the resin was 60 μm, and the film thickness at the outermost periphery was 90 μm.

  In FIG. 8B, a metal stamper A (first stamper) 103 in which an information pattern (first pattern) of the L3 layer is formed in advance on the cover sheet 2p resin 102 is a center hole (not shown). And the glass substrate 101 are aligned and overlapped. Thereafter, ultraviolet light is irradiated from the UV light source 105 through the glass substrate 101, and the cover sheet 2p resin 102 is cured. The cover sheet 2p resin 102 may be overlaid on the glass substrate 101 after being applied to the stamper A103. For simplicity, the cover sheet 2p resin 102 is a single layer, but in order to satisfy transferability, peelability, and thickness accuracy, a plurality of resins may be used in combination.

  In FIG. 8 (3), after the cover sheet 2p resin 102 is cured, the stamper A 103 is peeled off, and an information pattern 104 (pits and guide grooves) of the L3 layer is formed on the glass substrate. The peeled metal stamper A does not deteriorate even when irradiated with a UV light beam, and can be used repeatedly.

  In FIG. 8 (4), the L3 layer recording film 106 is formed on the information pattern 104 of the L3 layer. The L3 layer recording film 106 is a translucent film.

  In FIG. 8 (5), the 2p resin 107 for the intermediate layer 1 for forming an intermediate layer between the L3 layer and the L2 layer provided below the L3 layer is applied on the L3 layer recording film 106. The 2p resin 107 for the intermediate layer 1 is dropped in an annular shape on the inner peripheral side of the glass substrate 101 having a center hole (not shown), and the glass substrate is rotated and shaken to obtain a uniform thickness (second constant thickness). It was. The average film thickness of the resin was 10 μm, and the film thickness at the outermost periphery was 20 μm.

  In FIG. 8 (6), a metal stamper B (second stamper) 108 in which an information pattern (second pattern) of the L2 layer is formed in advance on the 2p resin 107 for the intermediate layer 1 has a central hole (see FIG. 8). (Not shown) is aligned with the glass substrate 101 and overlapped. Thereafter, ultraviolet light is irradiated from the UV light source 105 through the glass substrate 101, and the 2p resin 107 for the intermediate layer 1 is cured. The 2p resin 107 for the intermediate layer 1 may be superimposed on the glass substrate 101 after being applied to the stamper B108. For simplicity, the 2p resin 107 for the intermediate layer 1 is a single layer. However, in order to satisfy transferability, peelability, and thickness accuracy, a plurality of resins may be used in combination.

  In FIG. 9 (7), after the 2p resin 107 for the intermediate layer 1 is cured, the stamper B 108 is peeled off, and the information pattern 109 (pits and guide grooves) of the L2 layer is formed on the L3 layer recording film 106. The peeled metal stamper B does not deteriorate even when irradiated with a UV light beam, and can be used repeatedly.

  In FIG. 9 (8), the L2 layer recording film 110 is formed on the information pattern 109 of the L2 layer. The L2 layer recording film 110 is composed of a translucent film.

  In FIG. 9 (9), the 2p resin 111 for the intermediate layer 2 is applied on the L2 layer recording film 110 to form an intermediate layer between the L1 layer and the L1 layer provided below the L2 layer. The 2p resin 111 for the intermediate layer 2 was dropped in an annular shape on the inner peripheral side of the glass substrate 101 having the center hole, and the glass substrate was rotated and shaken to obtain a uniform thickness (third constant thickness). The average film thickness of the resin was 15 μm, and the film thickness at the outermost periphery was 30 μm.

  9 (10), a metal stamper C (third stamper) 112 in which an information pattern (third pattern) of the L1 layer is formed in advance on the 2p resin 111 for the intermediate layer 2 uses a central hole. And aligned with the glass substrate 101. Thereafter, UV light is irradiated from the UV light source 105 through the glass substrate 101, and the 2p resin 111 for the intermediate layer 2 is cured. The 2p resin 111 for the intermediate layer 2 may be superimposed on the glass substrate 101 after being applied to the stamper C112. For simplicity, the 2p resin 111 for the intermediate layer 2 is a single layer. However, in order to satisfy transferability, peelability, and thickness accuracy, a plurality of resins may be used in combination.

  In FIG. 9 (11), after the 2p resin 111 for the intermediate layer 2 is cured, the stamper C 112 is peeled off, and an information pattern 113 (pits and guide grooves) of the L1 layer is formed on the L2 layer recording film 110. The peeled metal stamper C does not deteriorate even when irradiated with a UV light beam, and can be used repeatedly.

  In FIG. 10 (12), the L1 layer recording film 114 is formed on the information pattern 113 of the L1 layer. The L1 layer recording film 114 is composed of a translucent film.

  In FIG. 10 (13), the 2p resin 118 for the intermediate layer 3 for forming an intermediate layer between the L1 layer and the L0 layer provided below the L1 layer is applied on the L1 layer recording film 114. The 2p resin 118 for the intermediate layer 3 was dropped in an annular shape on the inner peripheral side of the glass substrate 101 having the center hole, and the glass substrate was rotated and shaken to obtain a uniform thickness (fourth constant thickness). The average film thickness of the resin was 20 μm, and the film thickness at the outermost periphery was 37 μm.

  In FIG. 10 (14), the metal stamper D (fourth stamper) 121 in which the information pattern (fourth pattern) of the L0 layer is formed in advance on the 2p resin 118 for the intermediate layer 3 uses the center hole. And aligned with the glass substrate 101. Thereafter, UV light is irradiated from the UV light source 105 through the glass substrate 1, and the 2p resin 118 for the intermediate layer 3 is cured. At this time, the L3 to L1 layer recording films 106, 110, and 114 need to be translucent at the wavelength of the UV light flux, and desirably the integrated transmittance is 20% or more. Further, when a visible light source is used instead of a UV light source and a resin that cures at the wavelength of the visible light beam is selected so that the integrated transmittance of the L3-L1 layer recording films 106, 110, 114 is 50% or more. The curing time can be shortened. The 2p resin 118 for the intermediate layer 3 may be overlaid on the glass substrate 101 after being applied to the stamper D121. For simplicity, the 2p resin 118 for the intermediate layer 3 is a single layer, but a plurality of resins may be used in combination in order to satisfy transferability, peelability, and thickness accuracy.

  In FIG. 10 (15), after the 2p resin 118 for the intermediate layer 3 is cured, the stamper D121 is peeled off, and the information pattern 116 (pits and guide grooves) of the L0 layer is formed on the L1 layer recording film 114. Similarly, the peeled metal stamper D does not deteriorate even when irradiated with a UV light beam, and can be used repeatedly.

  In FIG. 11 (16), the L0 layer recording film 117 is formed on the information pattern 116 of the L0 layer. The L0 layer recording film 117 typically includes a reflective film that does not transmit light.

  In FIG. 11 (17), a PC substrate (substrate) 115 is an injection-molded polycarbonate (PC) substrate, and no information pattern (pits or guide grooves) is formed on the substrate. Typically, the PC board 115 has a thickness of 1.1 mm, a diameter of 120 mm, and a center hole diameter of 15 mm. An adhesive layer 2p resin 120 between the L0 layer and the PC substrate 115 is applied. The adhesive layer 2p resin 120 is dropped in an annular shape on the inner peripheral side of the PC board 115 having a center hole (not shown), and the PC board is rotated and shaken to obtain a uniform thickness (fifth constant thickness). did. The average film thickness of the resin was 10 μm, and the film thickness at the outermost periphery was 20 μm. For simplicity, the PC board bonding 2p resin 120 is a single layer. However, in order to satisfy transferability, peelability, and thickness accuracy, a plurality of resins may be used in combination.

  In FIG. 11 (18), the glass substrate 101 after the process of FIG. 11 (16) is aligned and overlapped on the PC substrate bonding 2p resin 120 using a center hole (not shown). Thereafter, UV light is irradiated from the UV light source 105 through the PC board 115, and the PC board bonding 2p resin 120 is cured. The PC board bonding 2p resin 120 may be applied to the L0 layer recording film 117 and then overlapped with the PC board 115.

  In FIG. 11 (19), after the 2p resin 120 for PC substrate bonding is cured, the glass substrate 101 is peeled off, and the four-layer optical recording medium in the present invention is completed. If necessary, the film thickness may be adjusted by applying the cover sheet 2P resin in layers. Furthermore, you may form a cover-coat layer etc. as needed.

  FIG. 11 (19) is also a sectional view of the completed four-layer optical recording medium of the present invention. On the PC substrate 115, four recording layers L0 (117), L1 (114), L2 (110), and L3 (106) from the PC substrate side are an adhesive layer (120), an intermediate layer 3 (118), and an intermediate layer, respectively. It is arranged through the layer 2 (111) and the intermediate layer 1 (107), and the cover layer 102 covers the L3 layer. A light beam for recording / reproduction enters the medium from the direction of the cover layer 102.

  As described in FIGS. 8 (4), 9 (8), 10 (12), and 11 (16), the L3-L0 layer recording films 106, 110, 114 and 117 are formed by the following procedure. First, a dielectric layer is formed on the information patterns 104, 109, 113, and 116 of the L3 to L0 layers on which guide grooves and pits are formed, and an interface layer, a recording layer, and an interface as necessary. A layer, a reflective layer, and, if necessary, a high refractive index layer are sequentially formed. That is, a film is formed on the information pattern in the order of dielectric layer-recording layer-reflection layer. If necessary, a dielectric layer may be provided between the recording film and the reflective layer.

  The recording films 117, 114, 110, and 106 in the L0 to L3 layers may be a read-only type, a write-once type, a rewritable type, or a combination thereof.

  FIG. 12 is also a cross-sectional view of the completed four-layer optical recording medium of the present invention. Each intermediate layer is arranged on the PC board 115 from the PC board side, and the cover layer 102 covers it. A light beam for recording / reproduction enters the medium from the direction of the cover layer 102.

  In the present embodiment, it is transferred to a PC substrate after being stacked on a glass substrate, but may be stacked on a PC substrate as shown in Example 2, or a combination of the stacked layers may be combined. However, the present invention is not limited to this.

  In the peeling of the stamper for producing the first reflecting surface, the OK / NG rate of peeling was 99/100.

  In the peeling of the stamper for producing the second reflecting surface, the OK / NG ratio of the peeling was 97/100.

  In the peeling of the stamper for producing the third reflecting surface, the OK / NG rate of peeling was 99/100.

  In the peeling of the stamper for producing the fourth reflecting surface, the peeling OK / NG ratio was 98/100.

  By adopting the method for producing an optical recording medium of the present invention, it has become possible to supply an inexpensive optical recording medium having a four-layer structure with a stable peeling process, good yield.

The figure for demonstrating the 1st Example of the manufacturing method of the double layer recording medium of this invention. The figure for demonstrating the 1st Example of the manufacturing method of the double layer recording medium of this invention. The figure for demonstrating the 1st Example of the manufacturing method of the double layer recording medium of this invention. The figure for demonstrating the 1st Example of the manufacturing method of the double layer recording medium of this invention. The figure for demonstrating the 1st Example of the manufacturing method of the double layer recording medium of this invention. The figure for demonstrating the comparative example of the conventional manufacturing method. The figure for demonstrating the 2nd Example of the manufacturing method of the four-layer recording medium of this invention. The figure for demonstrating the 3rd Example of the manufacturing method of the four-layer recording medium of this invention. The figure for demonstrating the 3rd Example of the manufacturing method of the four-layer recording medium of this invention. The figure for demonstrating the 3rd Example of the manufacturing method of the four-layer recording medium of this invention. The figure for demonstrating the 3rd Example of the manufacturing method of the four-layer recording medium of this invention. The figure for demonstrating the 3rd Example of the manufacturing method of the four-layer recording medium of this invention. The figure for demonstrating the bonding process of this invention.

Explanation of symbols

01 transparent stamper 02 substrate 03 transparent resin film 04 ultraviolet ray 05 cover layer 06 central member 07 stage 11 first reflecting surface 12 first reflecting film 13 second reflecting surface 14 second reflecting film 15 third reflecting surface 16 Fourth reflective surface 21 Substrate side inner peripheral edge radius position a
22 Stamper side inner edge radius position b
23 Board side contact angle c
24 Stamper side contact angle d
101 glass substrate 102 2p resin for cover sheet 103 stamper A
104 L3 layer pattern 105 UV light source 106 L3 layer recording film 107 2p resin for intermediate layer 108 Stamper B
109 L2 layer pattern 110 L2 layer recording film 111 2p resin for intermediate layer 2 112 Stamper C
113 L1 layer pattern 114 L1 layer recording film 115 PC substrate 116 L0 layer pattern 117 L0 layer recording film 118 2p resin for intermediate layer 3 119 Transparent stamper 120 2p resin for adhesive layer 121 Stamper D

Claims (6)

Forming a transparent resin film on a first substrate having a central hole; pressing a second substrate having a central hole against the transparent resin film; and thereafter, applying the transparent resin to the transparent resin film. A method for producing a multilayer optical recording medium, comprising: supplying energy for curing the film; curing the transparent resin film; and then peeling the second substrate from the transparent resin film,
The film thickness of the outer edge of the first substrate of the transparent resin film is thicker than the film thickness in the vicinity of the center hole of the first substrate,
When the inner peripheral edge of the transparent resin film has a radial position of the inner peripheral edge of the transparent resin, where a is the first substrate side and b is the second substrate side, a <b. In the state, press
Then, supply energy to cure the transparent resin film,
A method for producing a multilayer optical recording medium, comprising: peeling off the second substrate from an end side of the central hole of the first substrate.   2. The multilayer optical recording according to claim 1, wherein c <d, where c is a contact angle with respect to the first substrate side surface of the transparent resin and d is a contact angle with respect to the second substrate. A method for manufacturing a medium.   3. The multilayer optical recording medium according to claim 1, wherein the first substrate is a resin transparent substrate, and the second substrate is a transparent stamper.   The multilayer optical recording medium according to claim 1 or 2, wherein the first substrate is a transparent substrate made of resin, and the second substrate is a glass substrate.   Radial position b of the transparent resin film formed on the substrate having the central hole and having the information pattern transferred to the inner peripheral end of the transparent resin film on the side where the information pattern is formed; The multilayer optical recording medium, wherein a <b> is a radial position a opposite to the side on which the information pattern is formed.   The transparent resin film is formed at an end on the inner peripheral side, an angle d formed with the surface on which the information pattern of the transparent resin film is formed, and a surface facing the side on which the information pattern is formed. 6. The multilayer optical recording medium according to claim 5, wherein the angle c is c <d.

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