JPH06101143B2 - 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.

[Prior Art] Conventional thin optical memory media are manufactured by forming a substrate with a thermoplastic resin such as polymethylmethacrylate or polycarbonate by injection molding or compression molding, and then providing a concave-convex guide groove on the surface. It was carried out by molding and then laminating an optical recording layer on this 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. 3, the substrate is an uneven guide groove portion.
In contrast to 31, the main reason is that unless the thickness of the base portion 32 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 present invention that can achieve the above object, on one surface of the heat-resistant sheet,
A resin having a heat deformation temperature lower than that of the heat-resistant sheet (hereinafter, abbreviated as easily deformable resin) is laminated directly or through another layer, and the obtained laminated sheet is sandwiched with a mold having unevenness on the surface under heating. By pressing, two laminated sheets formed by transferring uneven guide grooves to the surface of the resin layer are overlapped so that the heat-resistant sheet surfaces come into contact, and both surfaces having the guide grooves can be recorded with optical energy. A method for manufacturing a thin optical memory medium, which comprises the step of laminating various optical recording 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 surface of a heat resistant sheet to form a laminated sheet. Examples of the lamination method include a method of dissolving an easily deformable resin in a solvent and applying it to a heat resistant sheet by roll coating, a method of forming the easily deformable resin into a film and laminating it on the 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.

The above method is carried out again to form two laminated sheets. As another method of forming two laminated sheets, a method of stacking two heat resistant sheets and performing dipping coating on both surfaces thereof can also be adopted. This method is 2 at a time
It is preferable in that a single laminated sheet can be obtained.

Next, uneven guide grooves are transferred to the easily deformable resin surfaces of the two laminated sheets to form two substrates.
As this transfer method, only one inner surface was made uneven,
A method of pressing the laminated sheets one by one with a pair of molds,
Alternatively, it is possible to adopt a method in which two laminated sheets are superposed so that the respective heat-resistant sheets come into contact with each other, and then the two are laminated with a pair of molds each having unevenness on the inner surface under heating. The latter method has an advantage that the deflection of the substrate can be reduced because the pressing can be performed in a symmetrical state of the front and back.

Next, the two substrates are superposed so that their heat-resistant sheet surfaces come into contact with each other, and an optical recording layer capable of recording with light energy is laminated on both surfaces thereof, that is, the easily deformable resin layer surface provided with the guide groove. Thus, two optical memory media are simultaneously formed. The optical recording layer is laminated by various coating methods such as a vapor deposition method of a material described below, a dip coating method and a roll coating method.

The heat-resistant sheet used in the present invention, that is, the base film is a material that can withstand the temperature of the resin in the plastic state when the uneven pattern is formed, and a thermosetting heat-resistant film is preferable.
Typical examples of the thermosetting heat-resistant film include polyimide film, polyamideimide film, epoxy resin film, silicone resin film, polyesterimide film, polyester film, and tetrafluoroethylene-hexafluoropropylene copolymer film, tetra film. Examples thereof include fluororesin films such as fluoroethylene-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,
Terpene resin or picolite, acrylic resin, polyacrylonitrile, acrylonitrile-vinyl acetate copolymer, acrylonitrile-vinyl pyridine copolymer, acrylonitrile-methyl methacrylate copolymer and other acrylonitrile copolymers, polyacrylamide or , Diacetone acrylamide polymer obtained by acting acetone on acrylonitrile, polyvinyl acetate, acrylic acid ester or vinyl ester, vinyl ether or copolymer of ethylene with vinyl acetate, polyvinyl ether, polyamide, thermoplastic polyester, polyvinyl alcohol or Polyvinyl acetal resin, polyurethane, polyvinylcarbazole having a number average molecular weight of 6,000 or less, or polyvinylcarbazol of vinylcarbazole and ethylene or styrene. Nitrogen-containing vinyl polymers such as copolymers, dibutadiene polymers such as polybutadiene or butadiene-styrene copolymers and isoprene-isobutylene copolymers, polyethers, polycarbonates, polyethyleneimines, cellulosic resins or two of the above resins. There are blends of more than one kind 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.

In addition, the present invention does not require a step of distributing the raw material resin in the mold unlike the injection molding, so that the restriction of the cavity width set by the mold is extremely small, and from this point also, the substrate can be made thin. Can be achieved. For the above reasons, according to this method, the optical memory medium as a whole can be made thinner.

Further, since the optical recording layers are formed simultaneously on the two sheets, the productivity is improved.

Furthermore, in this method, since the back surfaces of the two substrates are not exposed when the optical recording layers are stacked, it is necessary to cover the back surfaces of the substrates even when using dipping coating for the stacking method. Since there is no problem, the dipping coating can be carried out very easily.

〔Example〕

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

Example 1 As shown in FIG. 1, the heat distortion temperature is 300 ° C. and the thickness is 50 μm.
2 pieces of the polyimide film of m (Kapton film of Toray Industries, Inc.) are brought into contact with each other with the pressure roll 2, and the heat distortion temperature is
After passing polymethylmethacrylate having a number average molecular weight of 80,000 at 85 ° C in a solution 3 in toluene, apply polymethylmethacrylate to both surfaces (one side of each of the two polyimide films) and then heat. Toluene was evaporated in the furnace 4 and 50 μm thick polymethylmethacrylate layers were laminated to form two laminated sheets (first
Figure). After that, as shown in FIG. 2, a stamper 12 having an uneven surface produced by electroforming from a master,
13 was heated and pressed by the press parts attached to the molds 10 and 11, respectively, to transfer the guide structure to the polymethylmethacrylate layer, and then cooled and solidified until the solution 3 was reached.

Then, the following light absorbing dye 1% solution 6 (solvent: diacetone alcohol: isopropyl alcohol = 2: 1 parts by weight), the light absorbing dye is applied on the guide groove, and the solvent is evaporated to form an optical recording layer. Two thin optical memory media were obtained by separating with a separating roll 15. The thickness of each medium was 0.1 mm.

〔The invention's effect〕

As described above in detail, on one surface of the heat resistant sheet,
Laminate an easily deformable resin directly or via another layer, and press the resulting laminated sheet with a mold having irregularities on the surface to transfer an irregular guide groove to the surface of the resin layer. The two heat-resistant sheets are laminated so that the surfaces of the heat-resistant sheets are in contact with each other, and an optical recording layer capable of recording with optical energy is laminated on both surfaces having the guide groove to obtain a thickness of 1.0 mm or less. It has become possible to manufacture such flexible optical discs with high productivity and more easily than ever before.

[Brief description of drawings]

Fig. 1 is a process drawing of applying polymethylmethacrylate to a polyimide film, Fig. 2 is an affirmative view of transferring guide grooves and applying light absorbing dye, and Fig. 3 is a cross section of a substrate manufactured by an injection molding method. It is a figure. 1: Polyimide film, 2: Pressure roll 3: Polymethylmethacrylate solution 4: Pressure furnace 10, 11: Mold 12, 13: Stamper, 14: Light absorbing dye solution 15: Separation roll 31: Guide groove part, 32: Base

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Claims (5)

[Claims] 1. A mold having a heat-resistant sheet, on one side of which a resin having a heat distortion temperature lower than that of the heat-resistant sheet is laminated directly or via another layer, and the resulting laminated sheet is heated to have irregularities on the surface. Two laminated sheets formed by transferring uneven guide grooves to the surface of the resin layer by sandwiching them are stacked so that the heat-resistant sheet surfaces are in contact with each other, and light energy is applied to both surfaces having the guide grooves. A method for manufacturing a thin optical memory medium, comprising a step of laminating an optical recording layer capable of recording with a recording medium. 2. The method for producing a thin optical memory medium according to claim 1, wherein an optical recording layer capable of recording with light energy is laminated by dipping coating. 3. The two laminated sheets are formed simultaneously by laminating a resin layer by dipping coating on both surfaces of two heat-resistant sheets that are in contact with each other. Alternatively, the method for manufacturing the thin optical memory medium according to the second aspect. 4. The method of manufacturing an optical memory medium according to claim 1, 2, or 3, wherein the resin layer is made of a thermoplastic resin. 5. The method for manufacturing an optical memory medium according to claim 1, wherein the heat resistant sheet is made of a thermosetting resin.