JP6445919B2 - Optical disc and manufacturing method thereof - Google Patents

Description

  The present invention relates to an optical disc and a method for manufacturing the same.

  Optical discs in which information that can be read by light is recorded as pits, such as so-called CDs (Compact Discs) and CD-ROMs, are known. Such an optical disk is formed, for example, by forming the pits on a resin-made disk-shaped substrate that transmits light, and forming a reflective film that reflects the light on the pits. When manufacturing such an optical disc, for example, when a resin substrate is formed, a transfer material such as a stamper is pressed against a predetermined surface of the substrate to form pits on the predetermined surface of the substrate.

JP-A-57-169324

  However, in the conventional method of forming pits by, for example, pressing a transfer material such as a stamper against a predetermined surface of the substrate when forming the substrate, the pits are affected by the effects of thermal contraction when the substrate is cooled. In some cases, the position and shape of the slab may be deformed. This has had a problem that it has a subtle effect on the sound quality during optical disc playback.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical disc in which pits are accurately formed.

  An optical disc according to an embodiment of the present invention includes a resin disk-shaped substrate in which both surfaces of at least a portion corresponding to an information recording area are formed flat, and an intermediate layer laminated on the substrate and having pits. And a reflective film that is laminated on the intermediate layer and reflects light.

  In such an optical disc, since pits are not directly formed on the substrate, the pit positions and shapes are not changed by thermal contraction, and pits can be formed accurately.

  The intermediate layer may include a first intermediate layer stacked on the substrate and a second intermediate layer stacked on the first intermediate layer and having the pits.

  The reflective film may be formed from an alloy containing silver. Here, when silver is used as the reflection film, the reflectance of the light in the reflection film is improved. However, there are cases where it is desired to suppress the reflectivity when reproducing an optical disc. Here, when the reflective film is an alloy containing silver, the reflectivity is preferably adjusted by adjusting the content of other metals contained in the alloy or changing the thickness of the alloy. I can do it.

  In the method of manufacturing an optical disc according to one embodiment of the present invention, a disk-shaped substrate made of a resin whose flat surfaces are flat at least at a portion corresponding to the information recording area is formed, and an intermediate layer is formed on the substrate. A pit is formed in the intermediate layer, and a reflective film for reflecting light is formed on the intermediate layer.

  In this manufacturing method, a substrate having flat surfaces is formed, an intermediate layer is then formed, and pits are formed in the intermediate layer. That is, the substrate has already been formed at the time when the pits are formed in the intermediate layer. Therefore, even if the substrate is thermally contracted when the substrate is formed, the pits are not affected when the pits are formed, so that the pits can be formed accurately.

  Further, when forming pits in the intermediate layer, the intermediate layer may be cured in a state in which the transfer material on which the pits are formed is pressed against the intermediate layer. In this method, the intermediate layer is cured while the transfer material is pressed against the intermediate layer. Therefore, when the transfer material is pressed against the intermediate layer, the intermediate layer is accurately filled in the concave portion of the transfer material, and when the transfer material is peeled off, the intermediate layer is already cured. Accordingly, it is possible to suppress the deformation of the intermediate layer that may occur after the transfer material is peeled off, to form the pits well, and to manufacture an optical disc having a good S / N ratio.

  In the above method, the intermediate layer may include a first intermediate layer and a second intermediate layer. In the method, the first intermediate layer is formed on the substrate, the second intermediate layer is formed on the first intermediate layer, and the pits are formed on the second intermediate layer. May be. In this case, for example, when pits are formed in the second intermediate layer, the transfer material on which the pits are formed is pressed against the second intermediate layer, and the second intermediate layer is pressed in a state where the transfer material is pressed. It may be cured. Thereby, as described above, it is possible to manufacture an optical disc having a good S / N ratio by forming the pits in a good shape.

  According to the present invention, it is possible to provide an optical disc in which pits are accurately formed.

1 is a schematic perspective view showing an example of an optical disc 1 according to a first embodiment of the present invention. It is sectional drawing of the optical disk 1 in the AA 'cross section of FIG. FIG. 2 is a schematic perspective view of the optical disc 1 as viewed from the bottom surface direction of FIG. 1. 4 is a flowchart for explaining a method of manufacturing the optical disc 1. It is a schematic perspective view for demonstrating the manufacturing method. It is sectional drawing for demonstrating the manufacturing method. It is a schematic perspective view for demonstrating the manufacturing method. It is sectional drawing for demonstrating the manufacturing method. It is sectional drawing for demonstrating the manufacturing method. It is sectional drawing for demonstrating the manufacturing method. It is sectional drawing for demonstrating the manufacturing method. It is sectional drawing for demonstrating the manufacturing method. It is sectional drawing for demonstrating the manufacturing method. It is sectional drawing for demonstrating the manufacturing method.

[Configuration of Optical Disc 1 According to First Embodiment of the Present Invention]
First, the outline of the optical disc 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic perspective view showing an example of an optical disc 1 according to the first embodiment of the present invention. The optical disc 1 according to the present embodiment is an optical disc on which information readable by light is recorded as pits such as a so-called CD (Compact Disc).

  For example, information is recorded on the optical disc 1 according to the present embodiment from the inner circumference side to the outer circumference side. When reproducing the recorded information, for example, the irradiation light 3 is irradiated from the irradiation device 2, and the optical disk 1 is irradiated with the irradiation light 3 through the polarizing element 6 and the lens 7. The reflected light 4 reflected from the optical disk 1 is irradiated with the light receiving device 5 through the lens 7 and the polarizing element 6. The light receiving device 5 receives the reflected light 4, discriminates information recorded on the optical disc 1 according to the form of the reflected light 4, and reproduces this information.

  Next, the configuration of the optical disc 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view of the optical disc 1 taken along the line AA ′ of FIG. FIG. 3 is a schematic perspective view of the optical disc 1 as viewed from the lower surface direction of FIG. In FIG. 3, a part of the configuration of the optical disc 1 is omitted.

  The optical disc 1 includes a disk-shaped substrate 101, and a first first intermediate layer 102, a second intermediate layer 103, a reflective film 104, a protective layer 105, and a print layer 106, which are sequentially stacked on the substrate 101. Prepare. The irradiation light 3 described above passes through the substrate 101, the first intermediate layer 102, and the second intermediate layer 103 and is reflected by the reflection film 104.

  The substrate 101 is formed in a disk shape having an opening at the center. Further, as shown in FIG. 2, the substrate 101 according to the present embodiment is not formed with pits, and at least the upper and lower surfaces corresponding to the information recording area are formed flat. The substrate 101 is made of a resin material such as polycarbonate having a permeability of about 1.2 mm.

  As shown in FIG. 2, like the substrate 101, the first intermediate layer 102 is formed in a disk shape with an opening at the center. However, the thickness of the first intermediate layer 102 is smaller than that of the substrate 101 (for example, 2 μm to 50 μm). The first intermediate layer 102 has a flat upper surface and lower surface, as with the substrate 101. The first intermediate layer 102 is formed of, for example, an ultraviolet curable resin material such as a translucent acrylic radical polymerization adhesive.

  As shown in FIG. 2, like the substrate 101, the second intermediate layer 103 is formed in a disk shape having an opening at the center. The second intermediate layer 103 constitutes an “intermediate layer” together with the first intermediate layer 102. In the second intermediate layer 103, a recess for forming the pit P is formed. The second intermediate layer 103 is formed of, for example, an ultraviolet curable resin material such as a translucent acrylic radical polymerization adhesive. The thickness of the second intermediate layer 103 is, for example, 2 μm to 50 μm.

  As shown in FIGS. 2 and 3, a reflective film 104 is formed on the second intermediate layer 103 on which the pits P are formed. The pit P is a convex portion provided on the surface irradiated with the irradiation light 3. As shown in FIG. 3, each pit P has a length corresponding to the recorded information along the rotation direction of the optical disc 1. The reflective film 104 may be made of aluminum, but may be formed of a metal having a higher reflectance than aluminum, for example. For example, the reflective film 104 is formed from an alloy containing silver (Ag). Such an alloy may be, for example, an alloy formed by adding an additive capable of adjusting the reflectance to silver. In such a case, the silver ratio may be 99% or more, for example, and the additive ratio may be 1% or less, for example.

  As shown in FIG. 2, the protective layer 105 protects the reflective film 104 from oxidation. For example, the protective film 105 is formed of a resin material such as an acrylic radical polymerization adhesive that can prevent oxidation of the reflective film 104.

  As shown in FIG. 2, the print layer 106 is an ink layer that is visible from the upper surface of the optical disc 1 and displays visible characters, patterns, designs, and the like.

  Here, in the optical disc 1 according to the present embodiment, since the concave portion that directly forms the pit P is not formed on the substrate 101, the position and shape of the pit do not change due to thermal contraction, and the pit P is not formed. It is possible to form accurately.

  Further, in the optical disc 1 according to the present embodiment, the reflective film 104 is formed from an alloy containing silver. Here, when silver is used as the reflective film 104, the reflectance of light in the reflective film 104 becomes good. However, there is a case where it is desired to suppress the reflectance when reproducing the optical disc 1 or the like. Here, when the reflective film 104 is an alloy containing silver, the reflectance is suitably adjusted by adjusting the content of other metals contained in the alloy or changing the thickness of the alloy. I can do it.

[Method for Manufacturing Optical Disc 1 According to First Embodiment of the Present Invention]
Next, a manufacturing method of the optical disc 1 will be described with reference to FIGS. FIG. 4 is a flowchart for explaining the manufacturing method. 5 to 14 are diagrams for explaining the manufacturing method, in which FIGS. 5 and 7 are perspective views, and FIGS. 6 and 8 to 14 are cross-sectional views.

  As shown in FIG. 4, in the manufacturing method, the substrate 101 is formed in step S1, the first intermediate layer 102 is formed in step S2, the second intermediate layer 103 is formed in step S3, and in step S4. Pits are formed in the second intermediate layer 103, the reflective film 104 is formed in step S5, the protective film 105 is formed in step S6, and the printing layer 106 is formed in step S7.

  As shown in FIGS. 5 and 6, in step S <b> 1, at least a disk-shaped substrate 101 made of a resin having flat surfaces on both sides corresponding to the information recording area is formed. The substrate 101 can be formed by various methods, but may be formed by, for example, injection molding.

  As shown in FIGS. 7 to 9, in step S <b> 2, the first intermediate layer 102 is formed on the substrate 101. The first intermediate layer 102 can be formed by various methods. For example, the first intermediate layer 102 may be formed by a spin coating method as follows. That is, as shown in FIG. 7, the substrate 101 is rotated, and in this state, a liquid resin 102A that is cured by ultraviolet rays or the like is supplied from the nozzle 11. As a result, the resin 102A is applied onto the substrate 101 to become the resin 102B. Next, as shown in FIG. 8, the resin 102B is cured by ultraviolet UV. As a result, the first intermediate layer 102 is formed as shown in FIG. Further, in order to increase the affinity with the resin forming the second intermediate layer 103, the first intermediate layer 102 is completely cured on the first intermediate layer 102 (or the resin 102B) before being completely cured. It is also possible to form the second intermediate layer 103.

  As shown in FIG. 10, in step S <b> 3, the second intermediate layer 103 is formed on the first intermediate layer 102 formed on the substrate 101. The second intermediate layer 103 can be formed by various methods. For example, the second intermediate layer 103 may be formed by a spin coating method as follows. That is, for example, by a process similar to the process described with reference to FIG. 7, as shown in FIG. 10, a liquid resin curable by ultraviolet rays or the like is applied to the upper surface of the first intermediate layer 102, and this is applied to the second intermediate layer 102. Intermediate layer 103.

  As shown in FIGS. 11 to 13, in step S <b> 4, pits are formed in the second intermediate layer 103. The pits can be formed by various methods, but may be formed by the stamper 12 or the like as follows. That is, as shown in FIG. 11, the transfer material on which the pits P are formed, such as the stamper 12, is pressed against the second intermediate layer 103. Next, as shown in FIG. 12, the second intermediate layer 103 is cured in a state where the stamper 12 and the like are pressed. For example, as shown in FIG. 12, the second intermediate layer 103 is irradiated with ultraviolet rays UV from below through the substrate 101 and the first intermediate layer 102, thereby curing the second intermediate layer 103. Accordingly, a recess corresponding to the pit P is formed on the upper surface of the second intermediate layer 103. As shown in FIG. 13, the transfer material such as the stamper 12 is peeled off from the first intermediate layer 102 after the second intermediate layer 103 is cured.

  As shown in FIG. 14, in step S <b> 5, the reflective film 104 is formed on the second intermediate layer 103. The lower surface of the reflective film 104 is formed along the pits P formed on the second intermediate layer 103. The reflective film 104 can be formed by various methods. For example, a method such as sputtering may be employed.

  Thereafter, as shown in FIG. 2, the protective layer 105 is formed on the upper surface of the reflective film 104 in step S6, and the printing layer 106 is formed in step S7, whereby the optical disc 1 described with reference to FIGS. It is possible to manufacture.

  Here, in the optical disk manufacturing method according to the present embodiment, the substrate 101 having both flat surfaces is formed, and then the first intermediate layer 102 and the second intermediate layer 103 are formed, and the second intermediate layer is formed. A pit is formed at 103. That is, the substrate 101 has already been formed at the time when pits are formed in the second intermediate layer 103. Therefore, even if the substrate 101 is thermally contracted when the substrate 101 is formed, the influence is not exerted when the pits are accurately formed, so that the pits can be accurately formed. Note that the first intermediate layer 102 has a function as a buffer material between the substrate 101 and the second intermediate layer 103.

  Further, in the method of manufacturing the optical disc according to the present embodiment, the second intermediate layer 103 is cured in a state where the transfer material (stamper 12) is pressed against the second intermediate layer 103. Accordingly, when the transfer material is pressed against the second intermediate layer 103, the second intermediate layer 103 is accurately filled in the uneven portions of the transfer material, and when the transfer material is peeled off, the second intermediate layer is already present. 103 is cured. Accordingly, it is possible to suppress the deformation of the second intermediate layer 103 that may occur after the transfer material is peeled off, and to form the above-described irregularities in a favorable manner, thereby manufacturing an optical disc with a good S / N ratio.

[Optical Discs According to Other Embodiments of the Present Invention]
In the first embodiment, the first intermediate layer 102 and the second intermediate layer 103 are provided between the substrate 101 and the reflective film 104, and these are used as the intermediate layer. However, for example, the intermediate layer may be formed from one layer or may be a laminated structure of three or more layers. For example, when the intermediate layer is formed from one layer, when the pit is formed in the intermediate layer, the transfer material on which the pit is formed is pressed against the intermediate layer, and the transfer material is pressed. The intermediate layer may be cured.

  DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Irradiation device, 3 ... Irradiation light, 4 ... Reflected light, 5 ... Light receiving device, 11 ... Nozzle, 12 ... Stamper, 101 ... Substrate, 102 ... First intermediate layer, 103 ... Second intermediate Layer 104, reflective film 105, protective layer 106, printed layer.

Claims (5)

A disk-shaped substrate made of resin in which both surfaces of at least a portion corresponding to the information recording area are formed flat;
An intermediate layer laminated on the substrate and having pits;
A reflective film that is laminated on the intermediate layer and reflects light ;
The intermediate layer is
A first intermediate layer laminated on the substrate;
A second intermediate layer laminated on the first intermediate layer and having the pits;
Have
The optical disk according to claim 1, wherein the first and second intermediate layers are made of an acrylic radical polymerization adhesive . The optical disk according to claim 1, wherein the reflective film is made of an alloy containing silver. The first intermediate layer functions as a cushioning material between the substrate and the second intermediate layer.
The optical disk according to claim 1, wherein the optical disk is an optical disk. Form a disk-shaped substrate made of resin with flat surfaces at least corresponding to the information recording area,
A first intermediate layer made of an acrylic radical polymerization adhesive is formed on the substrate by a spin coating method ,
A second intermediate layer made of an acrylic radical polymerization adhesive is formed on the first intermediate layer by a spin coating method,
Forming pits on the second intermediate layer ;
A method of manufacturing an optical disc, comprising: forming a reflective film that reflects light on the second intermediate layer. When forming the pits in the second intermediate layer,
The transfer material on which the pits are formed is pressed against the second intermediate layer,
The method of manufacturing an optical disk according to claim 4 , wherein the second intermediate layer is cured in a state where the transfer material is pressed.

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