JPS5836489A - Optical information recording material - Google Patents

Abstract

PURPOSE:To obtain a reflection type recording material facilitating a focus- servo or the like employing an inexpensive coating treatment by forming a silver mirror on the surface of a recording layer made of a resin containing a heat reducing agent in addition to a silver salt by a heat treatment. CONSTITUTION:A recording layer made of a resin C (preferably, water soluble resin such as polyvinyl alcohol) containing a silver salt A (e.g. silver nitrate) and a heat reducing agent B (e.g. 2-methyl-2-carboxyamide thiazolysine) is formed on a substrate (e.g. glass substrate) and then, heat treated to form a silver mirror on the surface thereof. Thus, an intended recording material is obtained. If necessary, besides above-mentioned components, a pigment or the like can be added to its as coloring component. The formation of the recording layer on the substrate can be done by applying and drying a solution of the components A, B, C mixed and dissolved in a solvent for the component C on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver mirror reaction type optical information recording member.

Conventionally, many types of information recording members for laser writing have been developed. Typical examples of these include the mori metal thin film type (tellurium, bismuth type), the dye thin film type, and the salt type. In other words, the metal thin film system consists of a thin film obtained by vapor-depositing a To-based or Bl'-based metal with a low melting point on a substrate, and has high sensitivity. Batch processing such as sputtering is required, which increases production costs, and there are also problems in terms of toxicity. Furthermore, an undercoat layer or the like is required to reduce thermal contact with the substrate. Dye thin film systems generally have high sensitivity and can be manufactured using relatively inexpensive manufacturing methods such as coating, but since they do not reflect and are inconvenient for focus servo or tracking servo, it is necessary to provide a reflective layer in addition to the negative layer. becomes necessary. Silver salt systems have silver particles distributed in gelatin, which has some disadvantages such as poor reflective properties and can be manufactured using a coating process, but silver particles are distributed in gelatin. This requires a complicated manufacturing process of preparing a silver salt emulsion, coating it on a substrate, irradiating it with light, developing it, and heating it, which is time-consuming and causes an increase in cost.

As a result of various attempts to address the above-mentioned problems, the present inventors succeeded in overcoming the conventional drawbacks by using a thermal reducing agent that exhibits reducibility with heat, and completed the present invention.

An object of the present invention is to provide a reflective type optical information recording member that facilitates focus servo and tracking servo. Another object of the present invention is to provide an optical information recording member that can be easily manufactured by an inexpensive coating process.

According to the present invention, there is provided an optical information member in which a recording layer made of a resin containing a silver salt supported on a substrate and a thermal reducing agent exhibiting heat-reducing properties is heat-treated to form a silver mirror on the surface thereof. provided. In general, the recording layer in the information recording member of the present invention is formed by applying a solution prepared by dissolving a silver salt and a thermal reducing agent in a resin solvent onto a suitable substrate and drying it, and then metal chains are precipitated on the surface and the recording layer has a specular gloss. It is formed by heat treatment until it appears.

In this way, according to the present invention, a single-layer recording member can be produced only by coating and heat treatment.

The silver salt used in the present invention may be any compound that is soluble in a solvent such as water, alcohol, or methyl cellosolve and can be decomposed by heat to precipitate metallic silver, such as silver nitrate, silver ammine complex, Examples include perchlorate steel. The resin used in the present invention is preferably a water-soluble resin, such as polyvinyl alcohol, polyvinylpyrrolidone, starch, gelatin, etc.
Other resins soluble in organic solvents, particularly resins soluble in polar solvents, such as polyvinyl butyral and cellulose acetate, can also be used.

The thermal reducing agent used in the present invention has the general formula (wherein R1 is a lower alkyl group having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, etc., and R2 is about 6 to 8 carbon atoms).
unsubstituted hetero fR or aromatic ring or substituted aromatic ring containing about 4 to about 9 nonmetallic atoms, such as jc-2-pyridyl, phenyl, 4-nitrophenyl, etc. Thiolate precursors having a substituent group consisting of atoms (the nine substituted atoms are the nonmetallic atoms required to complete the unsubstituted heterocycle) are useful, a specific example of which is 2-methyl-2-carboxyamidothiazolidine. ° Thiazolidine, 2-methyl-2-(2-pyridyl)-benzothiazoline and 2-methyl-2-(4
Mention may be made of substituted benzothiazolines such as -nitrophenyl)benzothiazoline. .

The basic components used to produce the information recording member of the present invention are as described above, but in addition, dyes and pigments may be dissolved or dispersed in the resin as coloring components. As the substrate, glass, plastic, etc. can be used.

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.

Example polyvinyl butyral (Toyobo Nisrex BM-5)
A solution is prepared by dissolving 800 g of silver nitrate, 3t12-methyl-(2-pyridyl)5-chlorobenzothiazoline and 90 g of ethanol in a mixed source. This solution is coated on a glass substrate to a thickness of about 2 μm using a spin coating method.

Next, when this is placed on a hot plate and heated to about 200° C., the surface of the film changes from yellow to brown to black with metallic luster in a few minutes. The reflectance of the recording member prepared in this way was 50%, and the light transmittance was 90 in the visible and near infrared (700-800) range. )(aNe
It was possible to write in 1μsec by concentrating 8mW onto 2.5μ with a laser (writing energy 8X10J/
dOt).

Claims (1)

[Claims] Optical information characterized by forming a silver mirror on the surface of a recording layer made of a resin containing a silver salt and a thermally reducible thermal reducing agent supported on a substrate by heat treatment. Recording parts.