JPS5836490A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To easily obtain a recording medium for recording and reproduction using a laser beam having a high reliability, free from deterioration in the quality and enabling high-sensitivity recording, by placing a monolayer information recording layer comprising a bronze-lustered organic pigment on a substrate. CONSTITUTION:A monolayer information recording layer 2 comprising a bronze- lustered organic pigment (e.g., copper phthalocyanine) is formed on a substrate 1 (pref. a plastic one made of an acrylic resin or the like) and preferably, a protective layer 3 (pref. a 0.5-2mum thin film made of polystyrene) is formed on said recording layer 2. To impart a bronze luster on the organic pigment layer, a thin film is formed on a heated substrate 1 by deposition such as vacuum vapor deposition of the organic pigment or other appropriate methods can be used. EFFECT:Improved contrast between the recorded part and the unrecorded part. Reproduction is possible both by reflection and transmission systems.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information recording medium having an improved dye layer as an information recording layer.

Conventionally, as this type of optical information recording medium, 4 types of various configurations are known.
Publication No. 3 discloses a structure in which a single layer of a 7-talocyanine compound is provided on a substrate.

However, since the reflectance on the surface of the organic pigment film is generally low, the contrast related to the reflectance between the areas inscribed by the laser beam and the unrecorded areas is low, making it difficult to reproduce the recorded information. be. In order to overcome this drawback, a two-layer structure has been proposed. That is, materials with high reflectivity such as AI, Mu91, Pt
, Ou.

The contrast is improved by providing a metal thin film of N1 or Or between the recording layer and the substrate or on the recording layer. However, even if the contrast is improved by such a method, it has the disadvantage that a high reflectance layer is required and the number of manufacturing steps is increased compared to the case where only the recording layer is used. This method has the disadvantage that the yield rate in the production of reeds is reduced due to the contamination of foreign matter such as dust at the boundary surface of the reeds. 1 more
There is a drawback that reliability deteriorates rapidly due to deterioration of optical characteristics due to oxidation of the high reflectance layer in the air. Furthermore, those in which the recording layer is sandwiched between the substrate and the high reflectance layer have the disadvantage that the recording sensitivity is reduced because the recording layer is not sufficiently recorded due to scattering of the recording layer by the laser beam. .

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of the prior art and to provide an optical information recording medium having a single layer structure of a dye layer by using an organic dye having a bronze luster.

That is, according to the present invention, there is provided an optical information recording medium having a single layer structure in which an information recording layer of an organic dye having bronze luster is supported on a substrate. The cross-sectional views are shown in the accompanying drawings. FIG. 1 shows a case consisting of only a substrate 1 and an information recording layer 2 without a protective layer, and FIG. 2 shows a case with a protective layer 3. The presence of a protective layer is not essential but desirable.

The substrate material used in the present invention is known to those skilled in the art and may be either transparent or opaque to the laser beam used. Must be transparent to laser light. On the other hand, when writing and recording is performed from the side opposite to the substrate, that is, from the surface of the recording layer, it is not necessary to be transparent to the writing laser beam.

However, when read and reproduced by transmitted light, it must be transparent to the read laser beam, and when read and reproduced by reflected light, it may be either transparent or opaque to the read laser beam. The substrate material may be a commonly used recording material support such as glass, quartz, ceramic, plastics, paper, plate-shaped or foil-shaped metal.

Plastics are preferred from the viewpoints of safety, improved recording sensitivity, flatness, light weight, workability, etc. Typical ``lastics'' include vinyl chloride resin, vinyl acetate resin, acrylic resin, methacrylic resin, polyester resin, nitrocellulose, polyethylene resin, polypropylene resin, polyamide resin, polystyrene resin, polycarbonate resin, and epoxy resin.

Examples of organic dyes constituting the information recording silver layer in the present invention include 7-thalocyanine derivatives such as copper phthalocyanine, lead 7-thalocyanine, and polychlorosteel phthalocyanine;
．． M'-dimethyl-substituted barylene pigments, N,M'-dianisole-substituted broken V-type pigments, etc., R-lylene/*Nll conductors, methylene blue, new methylene blue, and other phenothiazine dyes, halogen-substituted thioindigo, methyl, and halogen-substituted Indigo dyes and pigments such as Thio, Indigo Mado, Halinone dyes and pigments such as Indanthrene/Brilliant Orange, Indanthrene colors 1%
Anthraquinone dyes such as O, Co., Sorbet/Blue 12, Triphenylmethane dyes such as Nose 2, Mazienta, H-S, C1 Co. 1 Mordant Black 1 t.
or 11, cyanine dyes such as 1,5-bis-(dimethylamino)intermethinium verchlorate, and oframin. Such organic dyes are 1001~5㎯, preferably 1oooX~
A film thickness of 3 μm is applied onto the substrate. Applicable methods include thin film forming methods such as vacuum evaporation, sputtering, ion plate, vapor phase growth, epitaxial growth, doctor blade, cast, spinner, and immersion methods. In particular, vacuum evaporation methods such as resistance heating and electron beam heating are preferred from the viewpoints of ease of film formation, large degree of freedom in material selection, uniformity and smoothness of the thin film, simplicity of the film formation process, and large area. It is. Further, if necessary, it can be mixed with a binder to form a film.

The information recording layer in the present invention is prepared by forming a bronze luster on the organic dye layer formed on the substrate as described above. The organic dye bronze may be formed on both sides of the interface between the information recording layer and the substrate, the surface of the information recording layer, the interface between the information recording layer and the substrate, and the surface of the information recording layer. However, when the film thickness is thin, the entire recording layer exhibits bronze luster. Regardless of which surface has bronze luster, when optically recording and reproducing information, it is efficient to irradiate laser light from the surface with bronze luster.

Regardless of the present invention, the specular reflectance of bronze luster is generally expressed by the following equation in the case of vertically incident light.

(n-i) 2 for 2+ (n+1) 2 for 2+ In the above formula, r is the specular reflectance, n is the additive part of the refractive index λ of the absorbing medium, and k is the number of a expropriations, nk=-j-α( 2=wavelength of incident light, α=absorption coefficient of medium).

Strong reflections such as those from metals are usually called metallic reflections or metallic luster, and k is k.

Compounds also exhibit metallic reflection if k is large.

In this case, selective reflection is significant, meaning that much of the light near the absorption band is reflected, and the reflected light often has an additional color to the transmitted light.In pigment-related circles, this is called bronze luster. .

The formation of a bronze luster is achieved by crystallization, which increases the refractive index and absorption index, which previously increases the reflectance. Moreover, even if crystallization is not performed, the regular reflectance is increased by orienting the molecules and making the direction of the reflected light constant. Furthermore, it is known that even without crystallization or orientation, if a metal surface is polished to form an optically smooth surface, the reflectance increases. By these means, the reflectance can be increased.

Examples of the bronze gloss forming method in the present invention include the following methods based on bronze gloss and bronze gloss forming factors. When the thin film is annealed at a temperature and atmosphere suitable for the material, K-yellow crystallization occurs.
Molecule orientation and smooth surfaces are formed by pressurizing powder and the like. A thin film is formed on a crystalline substrate with aligned crystal planes. The substrate is heated and a thin film is formed on the substrate. In the case of a solution, a so-called casting method is suitable, in which slow cooling is performed after melting, and in the case of a solution, the melting solvent is gradually evaporated. The film is formed by orienting the dye in the presence of an electric or magnetic field.

The dye' is aligned and oriented using a liquid crystal, etc. Rub the surface of the sample to make it smooth. These methods and suitable combinations of these methods form a bronze luster.

In the optical information recording medium of the present invention, a protective layer may be provided as necessary. Safe! The I layer is transparent to the laser beam used, has high mechanical strength, and does not react with the recording layer.
<, Any material may be used as long as it has good film properties. Such a protective layer is Aj205.5102, SiQ, M
Inorganic materials such as gO, ZnQ, MgF2.0u-F2 are coated with a film thickness of 50 to 5oooX, preferably 100 to 2ooo
In A, a thin film was formed by a commonly used operation such as a vacuum evaporation method, a sputtering method, an ion plate method, or an ion cluster method. Particularly preferred organic materials are organic polymer compounds from the viewpoint of film formability and processability. For example, polystyrene, polyester, polycarbonate, polyxylene, polyvinyl chloride, polyacrylonitrile, polymethacrylonitrile, polyacrylic ester, polymethacrylate, polyvinyl acetate, polyethylene, polypropylene, polyepoxy, polyamide, polyurea, Examples include homopolymers and copolymers such as phenolic resins.
A thin film having a thickness of 01 to 5 μm, preferably 115 to 2 μm is formed by a commonly used thin film forming method such as a solvent coating method.

The laser beam applied to the optical information recording medium of the present invention must be selected depending on the absorption wavelength of the organic dye, since organic dyes generally have high wavelength selectivity. Therefore, depending on each organic dye, N2, He-0% Ar, He-N
Herby, dyes, semiconductor lasers, etc. are selected.

Next, in order to explain the present invention in more detail, examples will be given along with comparative examples, but the present invention is not limited thereto.

Comparative Example 1 Copper phthalocyanine was deposited on a glass plate with a thickness of 1 m using a vacuum evaporation method under the condition of a vacuum degree of 10-'Torr and the substrate temperature at room temperature to form a thin film of 3000 ml. When this sample was observed through the window of the evaporator, a reddish-purple bronze luster was observed.

Example 1 Copper phthalocyanine was deposited on a glass plate with a thickness of 1 m using a vacuum evaporation method at a vacuum level of 10-' Torr and a substrate temperature of 150° C. to form a thin film of 3000 μm. When this sample was observed under the same conditions as Comparative Example 1, reddish-purple bronze gloss was observed, and it was found that the bronze gloss in this example was superior to that in Comparative Example 1.

Comparative Example 2 Vapor deposition was performed under the same conditions as in Comparative Example 1, except that a 2-inch thick stainless steel plate was used as the substrate, and bronze luster was observed.

Example 2 Vacuum level 10 Torr on two thick stainless steel plates
Under the conditions of □, the substrate temperature was set to 1 and 150° C., and copper 7-talocyanine was deposited by vacuum evaporation to form a thin film of xooof. When this sample was observed under the same conditions as Comparative Example 1, reddish-purple bronze gloss was observed, and it was found that the bronze gloss of this example was superior to that of Comparative Example 2.

Comparative Example 6 A thin tube of 2900 λ was formed by depositing lead-7 talocyanine on a glass plate with a thickness of 1 by vacuum evaporation at a vacuum level of 10-'Torr and the substrate temperature at room temperature.

This thin film is 6330X with an angle of incidence of 15° on the thin film surface.
When the specular reflectance was measured by irradiating it with monochromatic light, it was 5.5-
Furthermore, when recording and playback was performed using an Rθ-No laser (6330), the contrast was 0 = A, where the reflectance of the recorded area and the unrecorded area were defined as M and B, respectively.
B/(A+B) was α27.

Example 6 A thin film was formed under the same conditions as in Comparative Example 5 except that the deposition was performed at a vacuum level of 10-'Torr, and the contrast C was measured to be 131.

The optical information recording medium according to the present invention manufactured as described above has various effects as described below. That is, since there is generally no metal layer with high thermal conductivity, the thermal energy of the laser light absorbed by the dye is effectively used to eliminate the dye, resulting in high-sensitivity recording. Also.

In the method for manufacturing an optical information recording medium of the present invention, the step of forming a reflective layer metal can be omitted, which simplifies the process by at least one step. Therefore, the reliability of the recording medium is improved because it is easy to prevent foreign matter such as dust from entering the recording medium. Furthermore, since there is no reflective layer metal, there is no risk of quality deterioration due to oxidation of the metal in the air. Further, if the bronze gloss is large, the contrast between the recorded area and the unrecorded area is improved.

Furthermore, reproduction can be performed using both reflective and transmissive methods.

[Brief explanation of the drawing]

In the accompanying drawings, FIG. 1 is a sectional view showing the basic structure of the optical information recording medium of the present invention, and FIG. 2 is a cross-sectional view showing the optical information recording medium of the present invention with a protective layer. 1... Substrate, 2... Information storage layer, 3... Protective layer. Figure 1 Figure 2

Claims (1)

[Claims] 1. An optical information recording medium for recording and reproducing data by causing a state change with a laser beam, characterized in that a substrate carries a single-layer information storage layer of an organic dye having a bronze luster.