JPH06101144B2 - Thin optical memory-method for manufacturing medium - Google Patents

Description

The present invention relates to a method for manufacturing an optical memory medium, and more particularly to a method for manufacturing a grooved optical memory medium such as a flexible optical disk.

[Conventional technology]

A conventional thin optical memory medium is manufactured by first molding a thermoplastic resin such as polymethyl methacrylate or polycarbonate as a substrate by injection molding or compression molding in a state where uneven guide grooves are provided on the surface, and then, This has been done by stacking an optical recording layer on a substrate.

With such a method, it is difficult to reduce the thickness and it is difficult to manufacture an optical memory medium having a thickness of 1.0 mm or less. As shown in FIG. 5, the substrate is an uneven guide groove portion.
In contrast to 51, the main reason is that unless the thickness of the base portion 52 therebelow is made considerably large, molding is difficult due to problems such as strength.

[Object of the Invention]

The present invention has been made in view of the above problems, and an object thereof is to provide a method by which a flexible optical disk or the like having a thickness of 1.0 mm or less can be manufactured more easily than before.

[Means for solving problems]

The above-mentioned object of the present invention is obtained by laminating a resin having a heat deformation temperature lower than that of the heat-resistant sheet (hereinafter, abbreviated as easily deformable resin) on one surface or both surfaces of the heat-resistant sheet, directly or through another layer. The laminated sheet is pressed with a metal mold having irregularities on the surface to transfer the irregular guide grooves to the surface of the resin layer, and then optical recording capable of recording with optical energy on the surface having the guide grooves. This is achieved by stacking layers.

Hereinafter, the present invention will be described in more detail. In one embodiment of the present invention, first, an easily deformable resin is laminated on one side or both sides of a heat resistant sheet to form a laminated sheet. As this laminating method, a method of dissolving an easily deformable resin in a solvent or the like and applying it to a heat resistant sheet by roll coating,
There is a method in which the easily deformable resin is formed into a film and laminated on a heat resistant sheet. Further, the easily deformable resin and the heat resistant sheet may be bonded together via an adhesive layer. With this method, a sufficiently large adhesive force is obtained, and the heat resistant sheet is protected by the adhesive layer.

Next, the laminated sheet is pressed while being heated, and an uneven guide groove is transferred to the surface of the easily deformable resin to obtain a substrate.
The sandwiching of the laminated sheet having the easily deformable resin on both surfaces may be performed using a pair of molds each having unevenness on the inner surface. The sandwiching of the laminated sheet having the easily deformable resin layer on only one surface may be performed using a pair of molds having unevenness on only one inner surface.

The means for heating during pinching may be installed in the mold itself,
It may be prepared separately from the mold.

Then, on the surface of the substrate on which the guide groove is transferred, that is, the surface of the easily deformable resin layer, an optical recording layer capable of recording with optical energy is laminated by various laminating methods such as vapor deposition, roll coating and dip coating. To do. Through the above steps, a thin optical memory medium can be manufactured.

An optical memory medium having optical recording layers on both sides has a large amount of information to be stored per sheet and is economical, and since it has a symmetrical shape on the front and back sides, it has the advantage that the deflection of the optical memory medium itself is reduced.

The heat-resistant sheet used in the present invention, that is, the base film, can withstand the temperature of the clothing-deformable resin in the plastic state when the uneven pattern is formed, and a thermosetting heat-resistant film is preferable. Typical examples of this thermosetting heat-resistant film, a polyimide film, a polyamide-imide film,
There are epoxy resin films, silicone resin films, polyester imide films, polyester films, and fluororesin films such as tetrafluoroethylene-hexafluoropropylene copolymer films and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer films.

The easily deformable resin used in the present invention is preferably a thermoplastic resin. Typical examples of the thermoplastic resin include polysulfone, polyolefin, polyolefin copolymers such as ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer and ethylene-propylene copolymer, polyolefin halides, vinyl acetate. -Vinyl chloride copolymers such as vinyl chloride copolymers and vinyl chloride-acrylonitrile copolymers, vinylidene chloride-vinyl chloride copolymers and vinylidene chloride copolymers such as vinylidene chloride-vinylidene chloride-vinyl chloride-acrylonitrile copolymers , Polystyrene, styrene-acrylonitrile copolymer (AS resin) and styrene-
Styrene copolymers such as acrylonitrile-butadiene copolymer (ABS resin), p-methylstyrene, 2,5-dichlorostyrene, vinylanthracene, etc., or their copolymers (styrene copolymers), coumarone and Indene or a copolymer of these with styrene,
Acetone acts on terpene resin or picolite, acrylic resin, polyacrylonitrile, acrylonitrile-vinyl acetate copolymer, acrylonitrile-vinyl pyridine copolymer, acrylonitrile-methyl methacrylate copolymer, polyacrylamide or acrylonitrile. Diacetone acrylamide polymer, polyvinyl acetate, acrylic acid ester, vinyl ester, vinyl ether, ethylene etc. and vinyl acetate copolymer, polyvinyl ether, polyamide, thermoplastic polyester,
Polyvinyl alcohol or polyvinyl acetal resin, polyurethane, nitrogen-containing vinyl polymer such as polyvinylcarbazole having a number average molecular weight of 6,000 or less or polyvinylcarbazole copolymer of vinylcarbazole and ethylene or styrene, polybutadiene or butadiene-styrene copolymer, Examples thereof include diene polymers such as isoprene-isobutylene copolymers, polyethers, polycarbonates, polyethyleneimines, cellulosic resins or blends of two or more kinds of the above resins, or blends with other thermoplastic resins.

The material of the optical recording layer used in the present invention may be of any type as long as it can form a thin film to be recorded by light, and examples thereof include metals such as aluminum, bismuth, inorganic materials such as tellurium oxide and chalcogenide compounds. Compounds. These materials are generally used as an optical recording layer by sputtering or vacuum evaporation. Further, as the other optical recording layer material, a material mainly containing a light absorbing dye can be mentioned. As the light absorbing dye, cyanine, merocyanine,
Including azo, stilbene, phthalocyanine direct dyes, azo, anthraquinone, triphenylmethane, xanthene, azine acid dyes, cyanine, azo, azine, triphenyl, including triphenylmethane, naphthoquinone, xanthene, squalium and azulene. Methane basic dye, azo, anthraquinone, xanthene, triphenylmethane mordant / acid mordant dye, anthraquinone, indigoid vat dye, azo, anthraquinone, phthalocyanine, triphenylmethane oil soluble dye, etc. can do. These are mainly used as the optical recording layer by the various coating methods described above.

[Action]

In the method of the present invention, the guide groove portion and the base portion below the guide groove portion are formed of different materials to form the substrate, and since a high-strength heat-resistant sheet preformed on the base portion is used, the base portion is formed. The substrate can be easily formed without making the thickness relatively thicker than the guide groove portion.

Further, unlike the injection molding, the present invention does not require a step of distributing the raw material resin in the mold, so that the restriction of the cavity width set by the mold is extremely small. Can be realized.

For the above reasons, according to this method, the optical memory medium as a whole can be made thinner.

〔Example〕

Specific examples of the present invention will be shown below with reference to FIGS. 1, 2, 3 and 4, and the present invention will be described in more detail.

Example 1 Polymethylmethacrylate (easily deformable resin) having a heat distortion temperature of 85 ° C. and a number average molecular weight of 80,000 was dissolved in toluene, and the solution was heated at a heat distortion temperature of 300 ° C. or higher in FIG. Of 50 μm polyimide film (heat resistant sheet) 1
(Kapton film manufactured by Toray Industries, Inc.) was applied by roll coating to a uniform thickness. When the polyimide film 8 coated with the solution was heated and dried at 100 ° C. for 1 hour, a 50 μm-thick polymethylmethacrylate layer 2 remained after the toluene was evaporated, and a laminated sheet 3 was obtained. In FIG. 2, a stamper 4 having an uneven surface, which is manufactured by electroforming from a master, is used as a pressing part in a mold 5.
Then, the cushion layer 7 was attached to the mold 6. The laminated sheet 3 was heated and pressed by the press section to transfer the uneven guide groove to the polymethylmethacrylate layer 2, and then cooled and solidified to obtain a substrate.

After that, the light absorption dye of the following structural formula 1% solution (solvent: diacetone alcohol: isopropyl alcohol = 2: 1 parts by weight) was applied onto the substrate by roll coating, and the solvent was evaporated to form an optical recording layer to obtain a thin optical memory medium. .

Example 2 Polymethylmethacrylate (easily deformable resin) having a heat distortion temperature of 85 ° C. and a number average molecular weight of 80,000 was dissolved in toluene, and the solution was heated at a heat distortion temperature of 300 ° C. or more in FIG. Polyimide film (heat resistant sheet) with a thickness of 50 μm 8
(Kapton film manufactured by Toray Industries, Inc.) was coated on both sides with a uniform thickness by roll coating. When the polyimide film 8 coated with the solution is heated and dried at 100 ° C. for 1 hour,
After the toluene is evaporated, a polymethylmethacrylate layer 9 having a thickness of 50 μm remains on both sides of the polyimide film 8,
A laminated sheet 10 was obtained. In FIG. 4, stampers 11 each having a concavo-convex surface, which were manufactured by electroforming from a master, were attached to molds 12 and 13 as press parts, respectively. The laminated sheet 10 was heated and pressed by the pressing section to transfer the uneven guide groove to the polymethylmethacrylate layer 9, and then cooled and solidified to obtain a substrate. Then, the same light-absorbing dye solution as in Example 1 was applied on both surfaces of the substrate by dipping coating, the solvent was evaporated to form an optical recording layer, and a thin optical memory medium was obtained. The thickness of the optical memory medium manufactured according to Examples 1 and 2 was as follows.

Thickness (mm) Example 1 0.10 Example 2 0.15 [Effect of the Invention] As described in detail above, the easily deformable resin is laminated on one surface or both surfaces of the heat resistant sheet directly or through another layer,
The resulting laminated sheet is heated and sandwiched by a mold having irregularities on the surface to transfer the irregular guide grooves to the surface of the resin layer, and then the surface having the guide grooves is recorded with light energy. 1.0m by stacking possible optical recording layers
A flexible optical disk or the like having a thickness of m or less can be easily manufactured.

[Brief description of drawings]

1 and 3 are cross-sectional views of a sheet in which polymethyl methacrylate is laminated on a polyimide film. Second
FIG. 4 and FIG. 4 are cross-sectional views showing a process of transferring unevenness signals to the laminated sheet. FIG. 5 is a sectional view of a substrate manufactured by the injection molding method. 3,10: Laminated sheet 5,6,12,13: Mold 4,11: Stamper 7: Cushion layer 2,9: Polymethylmethacrylate resin 1,8: Polyimide film 51: Guide groove part, 52: Base part

Claims (3)

[Claims] 1. A resin having a heat distortion temperature lower than that of the heat resistant sheet is laminated on one side or both sides of the heat resistant sheet directly or through another layer, and the obtained laminated sheet has unevenness on the surface under heating. A thin type characterized in that an uneven guide groove is transferred to the surface of the resin layer by pinching with a mold, and then an optical recording layer capable of recording with optical energy is laminated on the surface having the guide groove. Method of manufacturing optical memory medium. 2. The method for producing an optical memory medium according to claim 1, wherein the resin layer is made of a thermoplastic resin. 3. The method for manufacturing an optical memory medium according to claim 1, wherein the heat resistant sheet is made of a thermosetting resin.