JPH02252147A - Back material for optical disk - Google Patents

Abstract

PURPOSE:To facilitate formation by forming the part of the back material corresponding to a recording part to a projecting shape. CONSTITUTION:The part of the back material 3 corresponding to the recording layer 2 provided in guide grooves 4 of a substrate 1 is formed to the projecting shape. The need for a spacer is eliminated if the back material 3 having high strength with this shape is used. The optical disk having a hollow structure is thus easily formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a backing material used for an optical disc on which information is recorded, reproduced, erased, etc. using laser light or the like.

[Prior Art] Optical recording media such as optical disks have excellent features such as high recording density, large capacity, low cost, and high access and transfer speeds. It is attracting attention as a recording medium that can replace discs.

Conventionally, optical disks have a hollow structure from the viewpoint of recording sensitivity and the like. The structure of a typical optical disc is shown in FIG. In FIG. 3, 1 is a substrate, 2 is a recording layer, and 6 is a spacer 3.
The backing material is 1 board and 6 spacer, and 3 backing material and 6
The spacer is bonded with an adhesive such as an ultraviolet curing agent. The spacers for the inner diameter part and the outer diameter part are aligned independently.

[Problems to be Solved by the Invention] However, in the conventional example described above, a spacer is required to obtain a hollow structure, and the process for positioning the spacer, bonding, etc. becomes complicated.

The present invention has been made in view of the above-mentioned problems, and provides a backing material having a novel structure in order to solve the drawbacks caused by the use of spacers.

[Means for Solving the Problems] According to the present invention, in a backing material forming a hollow structure of an optical disk having an optical recording layer on a substrate and having a hollow structure for recording and reproducing information using light, the backing material By warping the portion of the optical recording layer corresponding to the recording part in a convex shape in the direction opposite to the recording part, a hollow structure can be obtained without using a spacer, so that it is possible to form a hollow structure without using a spacer, so that it is possible to form a hollow structure without using a spacer. The process can be eliminated and simplified.

Furthermore, by making the convex shape arch-like, the strength against external forces can be increased compared to when a flat backing material of the same thickness is used.

Furthermore, by providing a fitting part on the backing material that can be fitted into the outer peripheral edge of the board, it is possible to simplify the manufacturing process such as omitting the bonding process and reduce costs. etc. can also be prevented.

In the present invention, the part of the backing material corresponding to the recording part of the optical recording layer formed on the substrate corresponds to the recording part in a hollow structure conventionally formed of a substrate, a spacer, and a backing material. This part corresponds to the spacer and backing material, and since the backing material itself in this part is curved in a convex shape in the opposite direction to the substrate, it is possible to form a hollow structure with the backing material and the substrate. That is, the inner and outer peripheral portions of the substrate other than the recording portion are in contact with the backing material, and convex portions of the backing material are formed concentrically along the recording portion.

The shape of the convex part may be any shape as long as it can form a hollow structure and be fixed to the substrate, and the cross section of the hollow structure formed along the concentric recording part As for the shape, the convex part can be formed by rectangle, triangle, trapezoid, arch shape, semicircle, etc.
An arch-shaped convex portion is preferred. Due to the arch shape, if an external force is applied to the manufactured optical disc, the force is dispersed, and the backing material is less likely to come into contact with the recording layer than when using a flat plate made of PC (polycarbonate) or the like of the same thickness. There will be less chance of getting hurt. That is, since the strength against external forces is increased, the material, thickness, etc. of the backing material can be set relatively freely. As long as the arch shape has a convex curved structure in the direction opposite to the substrate, the curvature etc. may be set appropriately. Normally, for a disk with a diameter of about 86 mm, the maximum gap between hollow structures is 0.1 to 0.5 m.
About m is sufficient.

Further, in the present invention, a fitting portion may be provided on the backing material and may be fitted to the outer peripheral edge of the substrate. The most basic shape of the fitting part is to cover the outer circumferential edge of the backing material or the outer circumferential edge surface of the substrate, and fix the substrate with an L-shaped pawl provided at the outer circumferential edge of the backing material. In this way, as long as it fits with the outer peripheral edge of the board and has a shape that allows the board to be fixed, it is not limited to the above-mentioned cursive claw. It may also be provided on the outer periphery. When fixing by fitting, the substrate and the backing material are not joined by adhesive, so it is difficult to apply force due to the difference in shrinkage rate between the substrate and the backing material, and deformation such as warping or twisting of the substrate is less likely to occur. Further, in the case of fixing by fitting as described above, the substrate can be easily fitted if the backing material is flexible to some extent.

The backing material may be transparent or opaque to the light irradiated during recording, playback, etc., and may be made of polycarbonate, ABS, etc.
Any material such as plastic such as resin, metal, synthetic paper, or paper may be used. Also, the thickness of the backing material is 0.1 to 1. It may be approximately 0 mm, but it should be set appropriately depending on the material used. In the case of an arch-shaped convex part, when the same material as the conventional flat backing material is used, the thickness may be about 25 to 75% of that of the conventional one.

The backing material can be manufactured by conventional methods such as embossing, injection molding, vacuum forming, etc. when using Plus Deck, and rolling, etc. when using other materials.

Next, configurations according to the present invention other than those described above will be explained. The substrate for the disk may be any material as long as it is transparent to the light irradiated during recording, reproduction, etc., and for example, plastics such as polycarbonate (PC) and polymethyl methacrylic (PMMA), glass, etc. can be used. .

Further, as the recording layer formed on the substrate, organic materials such as cyanine, naphthoquinone, and polymethine, and inorganic materials such as Te, In, Se, and Te alloys may be used. When bonding the backing material and the substrate using an adhesive, commonly used adhesives such as hot melt adhesives, UV curing adhesives, thermosetting adhesives, etc. may be used, and known adhesives such as ultrasonic fusion may be used. It can also be done by means of

[Example] Next, the present invention will be further explained by examples.

Example 1 FIG. 1 is a schematic cross-sectional view of an optical disc obtained in this example, and is a drawing that best represents the features of the present invention. 1 is a disk substrate, 2 is a recording layer, and 3 is a backing material 4, which is a groove transferred to the substrate.

In the optical disk shown in Fig. 1, the substrate 1 has a thickness of 1.2 mm.
This recording layer is made of a polymethine dye, and the backing material of No. 3 is made of PC having a thickness of 0.3 mm formed by embossing and adhered using a hot melt adhesive to form a hollow structure. The maximum distance between the recording layer and the backing material was 0.3 mm.

In addition, since a spacer was not necessary for positioning the backing material and the front material (substrate), it was sufficient to align the hollow holes.

Embodiment 2 FIG. 2 shows a second embodiment of the present invention, in which 1 is a substrate, 4 is a groove, 2 is a recording layer, 3 is a backing material, and has a fitting part 3'. ing. PC board (t=1.2mm
), and the same polymethine dye as in Example 1 was used in the recording layer. For the backing material in No. 3, injection molded vinyl chloride (thickness: 0.3 mm) was used.

This backing material 3 has a fitting part 3 (hook) on its outer periphery, so it can be easily removed from the board without using adhesive, and the process of aligning and gluing the spacer and backing material is greatly reduced. was able to be reduced to

A comparison was made between the case where the backing material of an ABS (thickness: 0.3 mm) molded product was actually adhered to the PC board with UV curable adhesive, and the case where it was attached using the snap-in method of this example. While the bonded substrate warped by about 0.5 mm after being left in an atmosphere of 90% humidity for 100 hours, in the case of the fitted type, the warp was less than 0.05 mm.

In addition, when using a snap-in type backing material as in this example,
Since the recording layer is exposed to almost the same environment as when exposed to the outside air, a protective film may be formed on the recording layer especially when the recording layer is easily exposed to moisture or the like.

[Effects of the Invention] As explained above, by making the part of the backing material of the optical disc corresponding to the recording part a convex part, it is possible to manufacture a hollow optical disc without a spacer through a simple process, and furthermore, the cost can be reduced. I can do it.

Furthermore, by forming the convex portion into an arch shape, the strength of the hollow structure can be increased.

In addition, by providing a fitting part such as a hook on the outer periphery of this backing material and attaching it by fitting it into the board, it is possible to further simplify the manufacturing process. Deformations such as warping and twisting can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of the optical disc shown in Example 1;
FIG. 2 is a schematic cross-sectional view of the optical disc shown in Example 2,
FIG. 3 is a schematic cross-sectional view of a conventional optical disc.

Claims (1)

[Scope of Claims] 1. In a backing material forming the hollow structure of an optical disc having an optical recording layer on a substrate and having a hollow structure in which information is recorded and reproduced by light, recording of the optical recording layer of the backing material is provided. A backing material for an optical disc, characterized in that a portion corresponding to the recording portion is curved in a convex manner in a direction opposite to the recording portion. 2. The backing material for an optical disc according to claim 1, wherein the convex portion has an arch shape. 3. The backing material for an optical disc according to claim 1, wherein the backing material has a fitting portion that can be attached to the substrate by fitting with the outer peripheral edge of the substrate.