JPH02128338A - Production of optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain stable preformat signals by subjecting the surface of a high-polymer substrate to a selective UV treatment, then forming an org. dye recording layer thereon and generating a difference in reflectivity in the org. dye recording layer itself to form preformat patterns. CONSTITUTION:A UV transmission plate 2 formed with patterns consisting of a gap parts 21 and patterned parts 22 is brought into contact with the surface of the high-polymer substrate 1 forming the preformats and is irradiated with UV rays 3 from the front surface side of the UV transmission plate 2. UV treated parts 4 and UV non-treated parts are formed on the high-polymer substrate 1 when the UV transmission plate 2 is removed after the irradiation of the UV rays. A solvent soln. of a dye as an org. dye is then applied on the surface of such high-polymer substrate 1 and the solvent is evaporated to provide the org. dye recording layer 5. The reflectivity of the org. dye recording layer formed in the UV treated parts 4 decreases to 80 to 10% of the reflectivity of the org. dye recording layer in the UV non-treated parts, by which low reflectivity parts 6 are formed and the preformat patterns are formed. The stable preformat signals are obtd. in this way.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for manufacturing an optical information recording medium (hereinafter referred to as an optical recording medium), and in particular, to a method for manufacturing an optical information recording medium (hereinafter referred to as an optical recording medium), in particular, an organic dye recording layer is formed by ultraviolet treatment on the surface of a polymer substrate. The present invention relates to a method of manufacturing an optical information recording medium in which a preformat pattern is formed on the optical information recording medium.

[Prior Art] Conventionally, an optical recording medium substrate has irregularities such as guide grooves and information bits formed on its information recording surface. As a method for forming irregularities on such a substrate, if the substrate is made of thermoplastic resin, there is a method of transferring the guide grooves of the master by injection method or heat press method, or if the substrate is made of thermosetting resin or thermoplastic resin. After applying a photocurable resin composition onto a transparent resin plate, a master is placed in close contact with the resin composition and the resin composition is cured by irradiating the resin composition with radiation (ultraviolet rays, X-rays, etc.) from the transparent resin plate side. A so-called 22 method is known in which a pattern of a master mold is transferred to a transparent resin plate.

However, thermoplastic resin substrates obtained by injection method or heat press method are susceptible to optical anisotropy and warping of the substrate after molding due to residual stress and molecular orientation due to thermal history during molding. There are problems as a substrate for recording media.

Further, in the substrate obtained by the No. 22 method, unreacted polymerization initiators and monomers tend to remain in the resin after photocuring, and these often have an adverse effect on the optical recording layer of the recording medium.

Cast molding is known as a method for manufacturing substrates for optical recording media that does not cause these problems. The conventional manufacturing method for optical recording media substrates using cast molding involves forming a preformat pattern of predetermined guide grooves and bits in an uneven shape on a substrate such as a glass plate or metal plate. A device for cast molding is created by positioning smooth glass plates as a mold and using a spacer as a mirror mold to face each other. A resin or a prepolymer containing a solvent is poured into this device and cured to obtain a substrate for an optical recording medium. Substrates for optical recording media obtained in this way can be produced using the injection method or heat press method.

Compared to the 22 method, almost no pressure is applied during molding, so optical anisotropy and warpage do not occur, and unlike the 2P material, it does not have an adverse effect on the recording layer.

[Problems to be Solved by the Invention] On the other hand, since an optical recording medium has a structure in which an optical recording layer is formed on a transparent resin substrate having an uneven shape, first, the above-mentioned injection method and heat treatment are performed on the transparent resin substrate. Press method, 2
The uneven shape must be formed by the P method or cast molding method, etc. In that case, the transfer yield of the stubber mold, transfer time, durability of the stubber mold, cost, etc. will affect the mass productivity and price of the optical recording medium. The problem is that it depends on the

In addition, since the recording sensitivity of the optical recording layer depends on the film thickness, uniform film formation is required, but since the optical recording layer is formed on an uneven surface, it is difficult to obtain uniformity of film thickness. Have difficulty.

Furthermore, since the optical recording layer is formed with an uneven shape, there are problems such as difficulty in reproducing the shape.

The present invention has been made in order to solve the problems of the prior art described above, and by forming a preformat pattern on the optical recording layer itself without forming an uneven shape on the substrate surface, the film of the optical recording layer can be improved. It is an object of the present invention to provide a method for manufacturing an optical recording medium that can easily control the thickness and obtain a stable preformat signal in a short manufacturing time and at a low cost.

[Means for Solving the Problems] and [Operation] That is, the present invention provides the organic dye recording layer by selectively treating the surface of a polymer substrate with ultraviolet light and then forming an organic dye recording layer thereon. This method of manufacturing an optical recording medium is characterized in that a preformat pattern is formed by creating a reflectance difference in the layers themselves.

The present invention will be explained in detail below.

Conventionally, it has been known that when the surface of a polymer film is treated with ultraviolet light, molecules are cut and polar groups are generated on the surface of the polymer film, thereby improving printability and adhesion. (“
Polymer J 26 (11) 763 pages, 1977, and "Basics and Applications of Polymer Surfaces (Part 2)" ■ Kagaku Dojin Publishing, 1986).

The present inventor has proposed that when a polymer substrate is subjected to ultraviolet treatment as described above and an organic dye recording layer is formed on the polymer substrate by a solution coating method, the portion of the organic dye recording layer that has been subjected to ultraviolet treatment The reflectance of the area is 20% or more compared to the non-UV treated area.
It was found that the reduction was 80%. Such a decrease in the reflectance of the organic dye recording layer is caused by a chemical reaction between the organic dye recording layer and the polar groups or low-molecular reactive substances on the surface of the polymer substrate generated by ultraviolet treatment of the polymer substrate during the coating process of a solvent solution. This is thought to be caused by the Therefore, after selectively treating the surface of a polymer substrate with ultraviolet rays, an organic dye recording layer is formed on the surface of the polymer substrate by a coating process, thereby forming organic dye recording layers in the ultraviolet-treated areas and non-treated areas. Selective reflectance differences occur in the layers. By utilizing such a difference in reflectance between the organic dye recording layers, it becomes possible to form a preformat pattern of an optical Q medium. Therefore, the method for forming a preformat pattern in the method of manufacturing an optical recording medium of the present invention is completely different from the conventionally known method of forming a preformat by providing an uneven shape on a substrate. A preformat is formed by a chemical reaction between a polar group or a low molecular weight reactive substance generated on the substrate surface and an organic dye recording layer.

FIGS. 1(a) to 1(C) are process diagrams showing an example of the method for manufacturing the optical recording medium of the present invention. In the same figure.

In the present invention, first, an ultraviolet transmitting plate 2 on which a preformat pattern consisting of voids 21 and patterning portions 22 is formed by microfabrication is brought into close contact with a polymer substrate l forming a preformat. 3 is irradiated from the upper surface side of the ultraviolet transmitting plate 2 (the side opposite to the polymer substrate 1). (See FIG. 1(a)) After irradiation with ultraviolet rays, the ultraviolet transmitting plate 2 is removed, and an ultraviolet treated part 4 and a non-ultraviolet treated part are formed on the polymer substrate l. (See FIG. 1(b)) Next, using a dye as an organic pigment, a solvent solution with a dye concentration of 1 to 10 wt% is applied to the surface of the polymer substrate l on which the ultraviolet ray treated area 4 and the non-ultraviolet ray treated area are formed. The organic dye recording layer 5 is provided on the polymer substrate by coating and evaporating the solvent. The reflectance of the organic dye recording layer formed in the UV-treated area 4 is reduced to 80% to 10% (0.8 to 0.1 times) of the reflectance of the organic dye recording layer in the non-UV-treated area. A lowered portion 6 is formed. As a result, a preformat pattern is formed on the surface of the polymer substrate 1 by the difference in reflectance of the organic dye recording layer without any uneven shape. (See Figure s1 (c)) The ultraviolet transmitting plate 2 used in the present invention is not particularly limited, but quartz glass is usually used. The preformat pattern formed on the ultraviolet transmitting plate 2 is usually formed by vapor-depositing chromium metal on quartz glass, coating it with photoresist, and then developing the preformat pattern on the photoresist by photolithography. It is obtained by etching and removing the chromium metal in the removed portions, and then removing the photoresist in the non-etched portions.

The photolithography technique described above can be performed using already known techniques.

In addition, optically transparent polymer materials are used as substrate materials for polymer substrates, such as polycarbonate, polyvinyl chloride, polymethyl methacrylate, polymethyl pentene, polysulfone, polystyrene, allyl diglycol carbonate ( A polymer compound such as RAV-7 (trade name, manufactured by Mitsui Petrochemicals) can be used. Particularly effective is polymethyl methacrylate, which easily generates decomposition products when resistant to ultraviolet light.

In the present invention, the organic dye used to form the organic dye recording layer is a cationic dye, in particular, a basic dye, which easily reacts with the ultraviolet-treated area of the polymer substrate. Preferred basic dyes include triphenylmethane,
Cyanine type.

xanthine series, azine series, thiazine series, acridine series,
Oxazine series, polymethine series, azo series, azomethine series,
Examples include anthraquinone dyes.

Further, as a solvent for dissolving the organic dye, diacetone alcohol, dichloroethane, a mixed solution of the two, etc. can be used.

A method of applying a solution in which at least one of the above organic dyes is dissolved is, for example, a spin code method.

It is possible to use conventionally known coating methods such as roll coating, gravure coating, spray coating, and curtain coating. The thickness of the organic dye recording layer is usually 4
00 to 1,600 people, preferably 700 to 1,100 people.

Furthermore, an optical recording medium can be obtained by laminating a protective substrate 8 on top of the organic dye recording layer via an adhesive layer 7, as shown in FIG.

For the adhesive layer 7 and the protective substrate 8, commonly used adhesives and protective materials can be used.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 On the surface of quartz glass with a thickness of 21-
Lm, the evaporated surface of the ultraviolet transmitting plate with a stripe-like preformat pattern of 7ILs and pitch IO pot formed on the Cr etched portion was closely attached to a polymethyl methacrylate substrate with a thickness of 0.4 mm. Next, ultraviolet rays were irradiated from the top of the quartz glass plate.The irradiation conditions were as follows.
Lamp power 160W/cm, tube/sample distance 1
The exposure time was 2 cm and the irradiation time was 30 seconds. After UV irradiation,
A polymethine organic dye (manufactured by Nippon Kayaku Co., Ltd., IR-820) represented by the following structural formula (I) is applied to the surface of a polymethyl methacrylate substrate that has been subjected to ultraviolet treatment (C2H5)2N? + '(C2)15)2
CI! 04゜(I) Dissolved in diacetone alcohol solvent to a concentration of 3.0% by weight and coated with a gravure coater to a thickness of 10 fl.
0 organic dye recording layers were formed. Next, apply a 5-layer thick ethylene-vinegar vinyl hot-melt adhesive (
PMMA (polymethyl methacrylate) with a thickness of 0.3 cm through 0 matai made, Elfan 0H-501)
A protective substrate was provided on top of the organic dye recording layer to produce a card-shaped optical recording medium as shown in FIG.

The reflectance of the organic dye recording layer of the In-made optical recording medium is:
It was 3% in the ultraviolet-treated area and 15% in the non-treated area. Using this difference in reflectance, a preformat pattern could be formed on the substrate surface.

Example 2 A card-shaped optical recording medium was manufactured by the same method as in Example 1, except that the organic dye in Example 1 was replaced with cyanine dye NK1414 (Nippon Kanko Dyes). The adhesive used was Elfan 011-506 manufactured by Nippon Matai.

The reflectance of the organic dye recording layer of the produced T recording medium was 51% in the ultraviolet-treated area and 20% in the non-treated area. It was possible to form a preformat pattern by utilizing the difference in reflectance between the organic dye recording layer in the ultraviolet-treated area and the non-treated area.

[Effects of the Invention] As explained above, according to the method for manufacturing an optical recording medium of the present invention, the following effects can be obtained.

■Compared to the conventional case of applying an organic dye to the surface of a substrate with an uneven shape, in the present invention, the organic dye is applied to the surface of a smooth polymer substrate, and a difference in reflectance is caused in the organic dye recording layer itself. To form a preformat pattern,
The thickness of the organic dye recording layer within the plane of the recording medium can be easily controlled, and an optical recording medium from which stable preformat signals can be obtained can be provided.

(2) The preformat forming method according to the present invention takes a shorter preformat forming time (manufacturing takt) than the conventional method of forming an uneven preformat.

■Compared to conventional stanbar molds, the present invention uses an ultraviolet transmitting plate with a Cr vapor-deposited preformat pattern formed on the surface of quartz glass. It has excellent durability because no pressure is applied. Therefore, it is possible to reduce costs.

[Brief explanation of the drawing]

FIGS. 1(a) to (C) are process diagrams showing an example of the method for manufacturing an optical recording medium of the present invention, and FIG. 2 is a diagram showing an example of a cart-shaped optical recording medium manufactured using the manufacturing method of the present invention. FIG.

Claims (1)

[Claims] After the surface of the polymer substrate is selectively treated with ultraviolet rays, an organic dye recording layer is formed thereon, thereby creating a reflectance difference in the organic dye recording layer itself and forming a preformat pattern. A method for manufacturing an optical information recording medium.