JPS62174749A - Optical recording method - Google Patents

Abstract

PURPOSE:To permit optical writing by a small-sized and lightweight semiconductor laser by irradiating IR rays of a specific wavelength on an optical recording medium contg. a diacetylene drive. compd. film having hydrophilic and hydrophobic parts in combination and a chroconic methine dye. CONSTITUTION:The chroconic methine dye is the compd. expressed by the formula and has an absorption peak at 800-900nm. Said compd. generates heat when irradiated with the IR light of said wavelength. Recording information is imaged to the prescribed position of the optical recording medium through a control circuit, semiconductor laser and optical system. The compd. of the formula existing at the imaging point absorbs the light and generates heat. The crystal body of the diacetylene deriv. compd. contained in the part irradiated with the light is then melted and made amorphous to form the part which does not discolor in the development process to be executed afterward. A GaAs junction laser having 800-900nm wavelength is adequate as the semiconductor laser to be used. The development of the latent image is executed by uniformly irradiating UV rays on the optical recording medium.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an optical recording method on an optical recording medium containing a diacetylene derivative compound, and in particular to an optical recording method using an 800-900 nm infrared laser as an optical writing means. Regarding recording methods.

[Conventional technology]

Recently, optical discs have been attracting attention as a central player in office automation. Optical discs can store large amounts of documents, literature, etc. on a single disc, so
Organize and manage documents, etc. in the office efficiently. Various types of recording media have been considered for this optical disc, but those using organic materials are attracting attention because of their cost and ease of manufacture.

Diacetylene derivative compounds are known as organic materials for such recording media. Focusing on the thermochromic properties of these compounds, a recording technology for use as laser recording media was disclosed in Japanese Patent Application Laid-Open No. 147807/1983. There is. However, this specification does not mention what kind of laser was used or should be used, and merely states that recording was performed using a laser.

The present inventors investigated laser recording of this diacetylene derivative compound using various lasers, and found that although thermochromic recording is possible using a large, high-output laser such as an argon laser, a small and relatively It was confirmed that laser recording could not be performed when a low-power semiconductor laser (wavelength: 800 to 900 r+m) was used.

However, for practical recording media such as optical discs, it is required that optical writing be possible using a small, low-output semiconductor laser.

Furthermore, since the conventional recording layer made of a diacetylene derivative compound as described above is formed using microcrystalline powder of the diacetylene derivative compound, the distribution of diacetylene derivative compound molecules within the recording layer is It is random, and therefore has disadvantages such as the transmittance and reflectivity of light differing depending on the location, and the degree of chemical reaction differing, so it is not necessarily suitable for high-quality, high-density recording.

On the other hand, JP-A-58-181052 and JP-A-59-
No. 60443 discloses various croconic methine dyes, and organic coatings containing these dyes absorb radiation in the width wavelength range of semiconductor lasers and generate heat, so that a so-called heat mode in which pits are formed due to laser energy is generated. Discloses that recording can be performed. but,
When performing recording by forming physical pits on the surface of a recording medium, the initial surface of the recording medium must be sufficiently smooth and at the same time be sufficiently smooth to prevent scratches on the surface of the recording medium after recording. In addition to requiring special care, it was also relatively difficult to perform high-density, high-sensitivity, and high-speed recording.

[Problem that the invention seeks to solve]

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to enable optical writing using a small and lightweight semiconductor laser, and to first record recorded information on a recording medium as a latent image. The object of the present invention is to provide an optical recording method in which the recorded information can then be visualized and read as desired.

Another object of the present invention is to provide an optical recording method capable of high-density, high-sensitivity, and high-speed recording.

Still another object of the present invention is to provide an optical recording method that has excellent stability and can obtain high-quality optically recorded images.

[Means for solving problems]

That is, the optical recording method of the present invention has a recording layer containing a monomolecular film of a diacetylene derivative compound having at least a lignophilic site and a hydrophobic site or a cumulative film thereof, and a croconic methine dye. 8 on the optical recording medium
A step of irradiating infrared rays of 00 to 900 nm according to recorded information to form a latent image; and a step of irradiating an optical recording medium on which the latent image is formed with ultraviolet rays to make the latent image visible. It is characterized by having.

The diacetylene derivative compound (hereinafter abbreviated as OA compound) having both a lignophilic site and a hydrophobic site used in the present invention refers to .4-It is a compound capable of addition polymerization reaction, and is typically represented by the following general formula % formula % (wherein, X is a hydrophilic group forming a hydrophilic moiety,
(m and n represent integers) Examples include compounds represented by the following formula.

Examples of the hydrophilic group X in the OA compound include a carboxyl group, an amine group, a hydroxy group, a nitrile group,
Examples include a thioalcohol group, an imino group, a sulfonic acid group, a sulfinyl group, or a metal or amine salt thereof.

The furkyl group represented by H(GHz)r forming the hydrophobic site is preferably a long-chain alkyl group having 1 to 30 carbon atoms. Further, n+m is preferably an integer of 1 to 30.

On the other hand, the croconic methine dye used in the present invention is a compound (including inner salts) having the following basic structure; ), and (80
It is a compound that has an absorption peak in the range of 0 to 900 nm and generates heat when exposed to infrared light at this wavelength. The croconickmetine dyes are typically of the following general formulas [13 to [r
V] is exemplified.

General formula [N] General formula [H] General formula [111] General formula [IV] Mountain general formula CI) CII: In II, R1 and R2 are alkyl groups (e.g., methyl group, ethyl group, n-propyl group) group, 1so-propyl group, n-butyl group, 5ee-butyl group, 1so-butyl group, L-butyl group, n-7mil group,
t-7mil group, n-hexyl group, n-octyl group, t-
octyl group, etc.), substituted alkyl groups (e.g. 2-hydroxyethyl group, 3-hydroxypropyl group, 4-hydroxybutyl group, 2-7cetoxyethyl group, carboxymethyl group, 2-carboxyethyl group, 3-carboxypropyl group, 2-sulfoethyl group, 3-sulfopropyl group,
4-sulfobutyl group, 3-sulfatepropyl group, 4
-sulfate butyl group, N-(methylsulfonyl)
-car8ylmethyl group, 3-(acetylsulf7mil)propyl group, 4-(acetylsulfamyl)butyl group, etc.), cyclic alkyl group (e.g., cyclohexyl group, etc.), allyl group, aralkyl group (e.g., benzyl group, etc.) group, phenethyl group, α-naphthylmethyl group, β-naphthylmethyl group, etc.), substituted aralkyl group (e.g., carboxybenzyl group, sulfobenzyl group, hydroxyhensyl group, etc.), aryl group (e.g., phenyl group, etc.), or Substituted aryl groups (e.g. carboxyphenyl group,
In particular, in the present invention, among these organic residues,
Hydrophobic ones are preferred.

Substituted or unsubstituted heterocycle 1 For example, a thiazole series nucleus (e.g. thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4.5-dimethylthiazole, 4.5-
diphenylthiazole, 4-(2-chenyl)-thiazole, etc.), benzothiazole series nuclei (e.g. benzothiazole, 5-chlorobenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5
．． 6-dimethylbenzothiazole, 5-furomobenzothiazole, 5-phenylbenzothiazole, 5-methoxybenzothiazole, 6-medoxybenzothiazole,
5,6-Simethoxybenzothiazole, 5,6-Sioxymethylenebenzothiazole, 5-Hydroxybenzothiazole, 8-Hydroxybenzothiazole, 4,
5,8.7-tetrahydrobenzothiazole, etc.),
Nuclei of the naphthothiazole series (e.g. naphtho[2,1-d
l thiazole, nut [1,2-dl thiazole, 5
-methoxynaphtho[1,2-dl thiazole, 5-ethoxynaphtho[1,2-dl thiazole, 8-methoxynaph] (2,1-dl thiazole, 7-ethoxynaphtho[2,1-dl thiazole, etc.), thionaphthene [
7,8-d] thiazole series nuclei (e.g. ?-methoxythionaphthene [7,13-dlthiazole), oxazole series nuclei (e.g. 4-methyloxazole, 5-methyloxazole, 4-phenyloxazole, 4.5
-diphenyloxazole, 4-ethyloxazole,
4.5-dimethyloxazole, 5-phenyloxazole), benzoxazole series nuclei (e.g. benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, 6-methylbenzoxazole, 5.6 -Simethylbenzoxazole, 5-methylbenzoxazole,
6-medoxybenzoxazole, 5-hydroxybenzoxazole, 8-hydroxybenzoxazole, etc.), naphthoxazole series nuclei (e.g., nut [2
, 1-dl oxazole, naphtho[1,2-dl oxazole, etc.), selenazole series nuclei (e.g. 4-methylselenazole, 4-phenylselenazole, etc.),
Nuclei of the benzoselenazole series (e.g. benzoselenazole, 5-chlorobenzoselenazole, 5-methylbenzoselenazole, 5,6-dimethylbenzoselenazole,
5-methoxybenzoselenazole, 5-methyl-6-methoxybenzoselenazole, 5.6-cyoxymethylenebenzoselenazole, 5-hydroxybenzoselenazole, 4.5. B.? -tetrahydrobenzoselenazole, etc.), naphthoselenazole series nuclei (e.g. naphtho [
2,1-dl selenazole, naphtho[1,2-dJ
selenazole), thiazoline series nuclei (e.g. thiazoline, 4-methylthiazoline, 4-hydroxymethyl-4
-methylthiazoline, 4,4-bis-hydroxymethylthiazoline, etc.), oxazoline series nuclei (e.g. oxazoline), selenazoline series nuclei (e.g. selenazoline), 2-quinoline series nuclei (e.g. quinoline, 8-methylquinoline, 6 -Chloroquinoline, 6-ethoxyquinoline, 8-ethoxyquinoline.

8-hydroxyquinoline), 4-quinoline series nuclei (e.g. quinoline, 6-ethoxyquinoline, 7-methylquinoline, 8-methylquinoline), 1-inquinoline series nuclei (e.g. inquinoline, 3,4-dihydroisoquinoline) ), 3-inquinoline series nuclei (e.g. isoquinoline), 3.3-dialkylindolenine series nuclei (e.g. 3,3-dimethylindolenine, 3,3-dimethyl-5-chloroindolenine, 3,3. 5-)limethylindolenine, 3,3.7-)limethylindolenine)
, pyridine series nuclei (e.g. pyridine).

5-methylpyridine), benzimidazole series nuclei (
For example, l-ethyl-5,8-dichlorobenzimidazole, 1-hydroxyethyl-5,6-dichlorobenzimidazole, l-ethyl-5-glolobenzimidazole, 1-ethyl-5,6-dibromobenzimidazole, -ethyl-5-phenylbenzimidazole, l-
Ethyl-5-fluorobenzimidazole, 1-ethyl-5-cyanobenzimidazole.

1-(β-acetoxyethyl)-5-cyanobenzimidazole, 1-ethyl-5-chloro-6-cyanobenzimidazole, 1-ethyl-5-fluoro-6-cyanobenzimidazole, 1-ethyl-5-acetyl Benzimidazole, l-ethyl-5-carboxybenzimidazole, ■-ethyl-5-ethoxycarbonylbenzimidazole, 1-ethyl-5-sulfamylbenzimitazole, ■=ethyl-5-N-ethylsulfamylbenzimidazole, l-Ethyl-5,6-difluorobenzimidazole, l-ethyl-5,6-dichlorobenzimidazole, 1-ethyl-5-ethylsulfonylbenzimidazole, l-ethyl-5-methylsulfonylbenzimidazole, 1-ethyl- 5-trifluoromethylbenzimidazole, 1-ethyl-5-trifluoromethylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylsulfinylbenzimidazole, etc.). X is a chloride ion, bromide ion, iodide ion, perchlorate ion,
Benzene sulfonate ion, p-1 luene sulfonate ion, methyl sulfate ion, ethyl sulfate ion,
Represents an anion such as propyl sulfate ion, X
is R1 and/maee e e -COO1so2NH-, -SO□-N-Go-, -5
0M, which does not exist when containing i02-N-So□-2, represents a cation such as a hydrogen cation, a sodium cation, an ammonium cation, a potassium cation, a pyridium cation, etc. n and m are 0 Or l.

In the general formula ([) (17), R3 and R4 represent an alkyl group such as methyl, ethyl, propyl, butyl, etc. R3 and R4 may also form a ring such as morpholino, piperidinyl, or pyrrolidino together with the nitrogen atom. I can do it. R5, R6, R7 and R8 represent a hydrogen atom, an alkyl group (methyl, ethyl, propyl, butyl, etc.), an alkoxy group (methoxy, ethoxy, propoxy, butoxy, etc.), or a hydroxy group; R5 and R6 can be combined with R7 and R8 to form a benzene ring.

Next, representative examples of the croconic methine dye used in the present invention are listed below, but for convenience, general formula [I] or [
ml betaine structure; however, in the preparation of these dyes, mixtures of the dyes in betaine form and salt form are obtained and are therefore used as mixtures.

Representative example (13) of general formulas [1] and [II]. e(1B)
08ct
ct(21). eC
H2G)(2 (23).θ(24)
. e(2B)
0e(27) Oe'
Representative example of U general formula [ml [IV] (35) θ.

(36) θ.

(37)　　　　　　　C).

(38) e.

The croconic methine dyes (1) to (42) above are 1
It can be used in one species or in combination of two or more.

The optical recording medium used in the present invention comprises a monomolecular film or a monomolecular cumulative film of the DA compound and the croconic methine dye, and may have a single-layer mixed system, a two-layer separated system, or a multi-layer A-layer system. good.

Here, the one-layer mixed system refers to one consisting of a mixed layer of a DA compound and croconic methine dye, and the two-layer separated system refers to
A multi-layer laminated system is one in which a layer containing an OA compound and a layer containing a croconic methine dye are laminated with a molecule a layer, and one or more layers containing an OA compound and one layer containing a croconic methine dye. Each of the above refers to a structure that does not include the two-layer separation system laminated on a substrate in a predetermined number and order.

A typical configuration of an optical recording medium used in the present invention is shown in FIGS. 1 and 2.

In FIG. 1, a single-layer mixed recording layer 2 is provided on a substrate 1, and in FIG. 1(A), an OA
The structure in which a mixed monomolecular film of compound 8 and croconic methine dye 7 was formed, and FIG. The configuration is as follows.

On the other hand, in FIG. 2, a two-layer separation system recording layer 2 is provided on the substrate 1, and in FIG. OA compound 8
In Fig. 2(B), a layer 2a consisting of a monomolecular film of OA compound 8 was formed on a layer 2b containing a croconic methine dye. It is of composition.

The layer 2b containing the croconic methine dye may be formed as a monomolecular film or a cumulative film thereof by a method described later.

As the substrate l of the optical recording medium used in the present invention, glass,
Various supporting materials such as plastic plates such as acrylic resin, plastic films such as polyester, paper, and metal can be used, but when recording by irradiating radiation from the substrate side, recording radiation of a specific wavelength is used. Use something that allows the lines to pass through.

OA previously formed on the substrate 1 or on the substrate 1
To form a monomolecular film or a monomolecular cumulative film as described above on a layer containing a compound or croconic methine dye, for example, 1. The Langmuir-Blodgett method (hereinafter abbreviated as LB method) developed by Langmuir et al. is used. The LB method is a molecule with a structure that has a hydrophilic group and a hydrophobic group in one molecule, and when the balance between the two (balance of amphiphilicity) is maintained appropriately, this molecule has a parent wood group on the water surface. This is a method of creating a monomolecular film or an accumulated film of monomolecular layers by utilizing the fact that the monomolecular layer is directed downward. When the monomolecular layer on the water surface has the characteristics of a two-dimensional system and zero molecules are sparsely dispersed, the two-dimensional ideal gas equation, rIA=kT, is established between the area per molecule A and the surface pressure n. , and becomes a "gas film °". Here, is the Boltzmann constant and T is the absolute temperature. If A is made sufficiently small, the intermolecular interaction becomes strong, resulting in a "condensed film (or solid film)" of a two-dimensional solid. It becomes °. The condensed film can be transferred layer by layer to the surface of a substrate such as glass.

In addition, a so-called mixed monomolecular film or mixed monomolecular cumulative film composed of two or more compounds can also be obtained by the same method as described above. At this time, it is sufficient that at least one of the two or more compounds constituting the mixed monomolecular film or the mixed monomolecular cumulative film has both a lignophilic site and a hydrophobic site,
Not all compounds are required to have both a woody part and a hydrophobic part; in other words, if at least one compound maintains a balance of amphipathic properties, a single compound on the water surface is required. A molecular layer is formed, and other compounds are sandwiched between amphiphilic compounds, resulting in the formation of a monolayer with molecular order as a whole.

A typical method for forming the recording layer 2 will be described below.

The one-layer mixed recording layer 2 shown in FIG.
It can be obtained by forming a mixed monomolecular film of compound A and croconic methine dye or a cumulative film thereof.

That is, first, a DA compound and a croconic methine dye are dissolved in a solvent such as chloroform, and this is developed on an aqueous phase to form a developed layer in which these compounds are developed into a film. To prevent these compounds from freely diffusing and spreading over the aqueous phase, a partition plate (or float) is provided to limit the area of the developed layer and control the aggregation state of these compounds, and a surface pressure n proportional to the aggregation state is applied. get. By moving this partition plate, the developed area can be reduced to control the state of aggregation of the film material, and the surface pressure can be gradually increased to set the surface pressure (2) suitable for producing a cumulative film. By gently moving the clean substrate up and down vertically while maintaining this surface pressure, a mixed monomolecular film of the OA compound and the croconic methine dye is transferred onto the substrate. A mixed monomolecular layer film is produced in this manner, and a mixed monomolecular layer cumulative film having a desired degree of accumulation is formed by repeating the above-mentioned operations.

In addition to the above-mentioned vertical dipping method, methods such as a horizontal deposition method and a rotating cylinder method can be used to transfer the monomolecular film onto a substrate. The horizontal deposition method is a method in which the substrate is brought into horizontal contact with the water surface and transferred, and the rotating cylinder method is a method in which a cylindrical substrate is rotated on the water surface to transfer a monomolecular layer onto the surface of the substrate. In the vertical immersion method described above, when a substrate with a woody surface is lifted out of water in a direction transverse to the water surface, a monomolecular layer is formed on the substrate with the woody groups of the OA compound facing the substrate as the first layer. Ru.

As the substrate is moved up and down, one layer of mixed monomolecular film is deposited with each step. Since the direction of the film-forming molecules is reversed between the pulling process and the dipping process, according to this method, a Y-shaped film is formed between each layer in which parent wood groups and parent wood groups, and hydrophobic groups face each other.

On the other hand, the horizontal deposition method is a method in which the substrate is brought into contact with the water surface horizontally and transferred, and a monomolecular layer with the hydrophobic groups of the OA compound facing the substrate is formed on the substrate. in this way,
Even when accumulated, there is no change in the orientation of the molecules of the OA compound, and an X-type film is formed in all layers with the hydrophobic group facing the substrate. A oriented cumulative film is called a type 2 film.

The rotating cylinder method is a method in which a cylindrical substrate is rotated on the water surface to transfer a monomolecular layer onto the surface of the substrate.

The method of transferring the monomolecular layer onto the substrate is not limited to these methods, and when using a large-area substrate, a method of extruding the substrate from a substrate roll into an aqueous phase may also be used.

Furthermore, the orientation of the aforementioned parent wood group and hydrophobic group toward the substrate is a general rule, and can be changed by surface treatment of the substrate, etc.

Details of these monomolecular film transfer operations are already known and are described, for example, in "New Experimental Chemistry Course 18 Interfaces and Colloids", pages 498-507, published by Maruzen.

In this way, the mixed monomolecular film and its cumulative film formed on the substrate have a high density and a high degree of order, so that variations in light absorption depending on location are extremely small. Therefore, by configuring the recording layer with such a film, a recording medium having a high-density, high-resolution recording function capable of optical recording and thermal recording can be obtained depending on the functions of the OA compound and the croconic methine dye. is obtained.

In addition, when forming the recording layer 2 of a two-layer separation system or a multilayer stack system, one or more of the layers 2a consisting of a monomolecular film of a DA compound or a cumulative film thereof and one or more of the layers 2b containing a croconic methine dye. may be laminated on the substrate 1 in a predetermined number of layers and in a predetermined order.

Layer 2a consisting of a monomolecular film of an OA compound or a cumulative film thereof
Prepare a developing solution containing an OA compound (without croconic methine dye) and use the LB method described above.
It can be formed on the substrate 1 or on other layers already formed on the substrate l.

The layer 2b containing the croconic methine dye is formed by applying a coating solution prepared by dissolving or dispersing the croconic methine dye in a suitable volatile solution onto the substrate 1 or other layers already formed on the substrate 1. , can be formed by coating to obtain a predetermined dry film thickness and then drying this. Alternatively, the above-mentioned LB method can be used by using an organic polymer with an appropriately balanced amphipathic property, such as a polymeric fatty acid such as stearic acid or alaxic acid, as a carrier molecule in the croconic methine dye. It can also be formed as a monomolecular film or a cumulative film thereof. Furthermore, if a long-chain alkyl group or the like is introduced into the croconic methine dye, a monomolecular film or a monomolecular accumulation thereof can be formed with good film formability.

When the layer 2b containing the croconic methine dye is formed by a coating method, when the croconic methine dye is in an amorphous state, alcohols such as methanol, ethanol, and impropatul can be used as the solvent for forming the coating solution. Types: Ketones such as acetone, methyl ethyl ketone, cyclohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide; sulfoxides such as dinotyl sulfoxide; tetrahydrofuran, dioxane,
Ethers such as ethylene glycol monomethyl ether; esters such as methyl acetate and ethyl acetate; benzene;
Examples include aromatics such as toluene, xylene, and ligroin, and when croconic methine is in the form of particles, dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloromethane, 1°2-dichloromethane, 1,1. 2-
Examples include halogenated hydrocarbons such as 1-dichloromethane, chlorobenzene, zlomobenzene, and 1,2-dichlorobenzene.

In addition, in order to improve the adhesion with the substrate 1 or with other layers, a binder made of a natural or synthetic polymer may be appropriately added to the coating liquid.

Application of such a coating liquid to the substrate 1 can be performed by a spinner rotation coating method, a dip coating method, a spray coating method,
Peed coating method, wire bar coach ink method,
Techniques such as a blade coating method, a roller coating method, and a curtain coating method are used.

When the recording layer 2 is of a mixed layer type, the thickness of the layer is suitably about 200 to 2 μm, particularly preferably from 400 to 5000 μm, and in the case of a two layer separated type, the thickness of each layer is as follows:
Approximately 1008 to 1μ is suitable, especially 200 to 5
A range to 000 is preferred. Furthermore, in the case of a multilayer laminated system, it is suitable that both the total thickness of the layers containing the individual OA compounds and the total thickness of the layers containing the individual croconic methine dyes are about 100 to 1. , especially 200~
A range to 5000 is preferred.

The mixing ratio of the OA compound and the croconic methine dye in the recording layer 2 is preferably about 1/15 to 1571, and optimally 1/10 to 10/1.

It should be noted that various protective layers may be provided on the recording layer 2 configured as described above, if necessary, and the present invention is applicable regardless of the lamination order of each layer in the case of a two-layer separation system or a multilayer lamination system. The invention is workable.

Furthermore, when forming the recording layer 2, its stability,
Various additives may be added to this to improve quality.

The optical recording method of the present invention can be carried out using an optical recording medium configured in this manner.

In this optical recording medium, by adding ultraviolet rays to the DA compound, the absorption wavelength of the recording layer changes and the apparent color changes. That is, the OA compound is initially almost colorless and transparent, but upon irradiation with ultraviolet rays, it polymerizes and changes into a polydiacetylene derivative compound. This polymerization occurs only by irradiation with ultraviolet light and not by the application of other physical energy such as heat. As a result of this polymerization,
It has a maximum absorption wavelength between 620 and 660I,
Changes to blue or dark color. This change in hue due to polymerization is an irreversible change, and once the recording layer changes from blue to dark, it does not return to a colorless transparent film.

In addition, when this polydiacetylene derivative compound that has changed to blue or dark color is heated to about 50°C or higher, it becomes about 54°C.
It has a maximum absorption wavelength at 0 nm and changes to a red film. This change is also an irreversible change.

On the other hand, the inventors of the present invention have conducted various studies on the recording layer having the above-mentioned structure, and found that it is possible to heat the recording layer at an appropriate temperature that does not destroy it or change its shape, and then heat it to a molten state. It has been found that even if the recording layer is irradiated with ultraviolet rays as described above, the recording layer does not change in color from blue to dark.

In other words, this means that the change to a blue or dark film as a result of polymerization of OA compounds due to ultraviolet irradiation is mainly due to D.
This is obtained by the highly ordered molecular orientation of the A compound, and when the orientation order of the OA compound within the layer is disturbed by heating the recording layer to melt the layer containing the OA compound as described above. This is thought to be due to a significant decrease in the number of molecules of OA compounds in a reactive positional relationship at the molecular arrangement level.

The optical recording method of the present invention performs recording by utilizing the characteristics of such an OA compound and the function obtained by combining it with a croconic methine dye.

An example of this recording method will be described in detail below.

First, recorded information is converted into an optical signal by a semiconductor laser via a suitable control circuit. This optical signal passes through an optical system and is placed, for example, on an optical recording medium mounting means, and is placed at a predetermined position on a disc-shaped optical recording medium having a synchronously rotating single-layer mixed recording layer as shown in FIG. The image is formed as shown in A),
Optical writing of recording information is performed using a semiconductor laser.

The semiconductor laser used at this time has an output wavelength of 80
Particular preference is given to using a 0-950 nm GaAs bonding laser.

At this time, there is no apparent change such as discoloration at the imaging point (light irradiation area) 3, but the croconic methine dye #1 in this area absorbs the light and generates heat, and due to this heat generation, The recording layer in the light irradiated region 3 is melted, and the highly ordered orientation of the constituent molecules in this region is disturbed. As a result, the highly ordered orientation of the DA compound in the light irradiation site 3 is disturbed, and the light irradiation site 3 becomes a portion that does not change color in the later development process.

Note that the IW irradiation conditions of the laser beam 4 during this writing may be selected depending on the configuration of the optical recording medium used, but at least the temperature of the light irradiation area 3 is such that the recording layer is melted and the constituent molecules are It is necessary to maintain a temperature that is sufficient to disturb the orientation order and not destroy the recording layer or deform its shape.

In this way, the recording layer was formed in the portion 5b due to the difference in the molecular orientation level, that is, in the portion 5b where the highly ordered orientation of the OA compound that was not irradiated with light was maintained. Upon irradiation with light, a latent image consisting of a portion 5a in which the highly ordered orientation of the OA compound is disturbed is formed, and recording information is written.

Note that such optical writing was not possible with conventional optical recording media made only of OA compounds, in which the [lA compound is sensitive to the above-mentioned semiconductor laser.

Here, as described above, since no recorded information is recorded in the recording layer 2 as an optically detectable image, the written recorded information cannot be read at this stage.

Therefore, if it is desired to read recorded information, it is necessary to visualize the latent image formed on the recording layer 2.

This latent image is visualized by uniformly irradiating the optical recording medium with ultraviolet light.

This ultraviolet irradiation maintains highly ordered orientation in the recording layer. That is, the OA compound in the portion 5b that was not irradiated with light during the previous writing polymerizes and changes into a polydiacetylene derivative compound, and this portion of the recording layer has a maximum concentration of f120 to 680 nm as shown in FIG. 3(C). The color changes to a blue or dark-colored film 8b having an absorption wavelength. On the other hand, in the part 5a that was irradiated with infrared rays during the previous optical writing, the highly ordered orientation of the OA compound is disturbed, so the polymerization reaction of the OA compound is difficult to occur, and in this part, the non-irradiated The color change to a blue or dark film as in the area 5b does not occur. Therefore, the latent image area 5a formed during the previous writing remains the color of the original recording layer, which is almost colorless and transparent, and is changed to a blue or dark color by this ultraviolet irradiation treatment. It remains in the darkened film Bb and is visualized as a white part 6a that can be optically distinguished from the blue or dark-colored film 8b.

Note that if the recording layer 2 is heated to a temperature of about 50'C or above after this ultraviolet irradiation treatment is completed, the polydiacetylene derivative compound in the blue or dark film 6b becomes red as described above. Since the color changes to , the recorded information written in the recording layer 2 as a latent image can be visualized as a white part 6a in the red film.

For this heating treatment of the recording layer, a heating means such as a heater may be used, or radiation such as infrared rays may be applied to the recording layer since the recording layer contains a croconic methine dye that absorbs radiation and generates heat. This can be carried out by irradiation, etc.

The optical recording method of the present invention using an optical recording medium having an F mixed type recording layer has been described above. is used, the imaging point 3 of the laser beam is the fourth
As shown in Figure (A), the layer 2b contains a croconic methine dye.

When the laser beam 4 is irradiated in this way, the croconic methine dye contained in the layer 2b absorbs the laser beam 4 and generates heat, and this heat generation causes the f
fj2. The portion above the imaging point 3 is melted, and a latent image 5a is formed according to the process described above as shown in FIG. 4(B). This latent image is formed by the above-mentioned ultraviolet ray irradiation treatment and by further heat treatment as necessary, to form a white color that can be optically distinguished from the blue, dark-colored, or red film 8b as shown in FIG. 4(C). It can be visualized as a portion 6a.

Note that as the optical recording medium, a disk-shaped disk (optical disk) was used in the above example, but of course, depending on the type of substrate that supports the recording layer containing the OA compound and croconic methine dye, optical tape, optical tape, etc. Optical cards etc. can also be used.

〔Effect of the invention〕

The effects of the optical recording method of the present invention are listed below.

(1) Since a combination of a croconic methine dye and a diacetylene derivative compound is used in the recording layer, optical writing is possible using a small and lightweight semiconductor laser, and high-speed recording is possible. Moreover, the recorded information is recorded as a latent image on the recording medium, and then the recorded information can be visualized and read as desired.

(2) Since the recording layer is composed of at least a diacetylene derivative compound as a monomolecular film or a cumulative film thereof, the constituent components of the recording layer have a high density and a high degree of order, and the recording layer is homogeneous. It is also formed with good surface properties. the result,
High-quality optical recording with excellent stability at high density and high sensitivity can be performed.

(3) Optical recording using an inexpensive recording medium having a highly homogeneous, large-area recording layer becomes possible.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples.

Example 1 General formula Cl2H2S"'CmiC-Cmic-c8H16-
A solution prepared by dissolving 1 part by weight of a diacetylene derivative compound represented by C0OH and 15 parts by weight of the above dye, a croconic methine dye represented by /L8, in chloroform at a concentration of 3XIO-3 mol/l was prepared at a pH of 8. 5 and developed on an aqueous phase with a cadmium chloride concentration of txto-3 mol/l. After removing the solvent chloroform, the glass substrate whose surface had been thoroughly cleaned was moved at a vertical speed of 1.0 mm in a direction across the water surface while keeping the surface pressure constant. The mixed monomolecular film of OA compound and croconic methine dye was transferred onto the substrate by gently moving it up and down at ocnZ minutes, and the mixed monomolecular film and the 5th, 21st, 41st, 101st, and 201st layers were replanted. An optical recording medium was prepared by forming a mixed monomolecular cumulative film on a substrate.

Using the optical recording medium thus obtained, the optical recording method of the present invention was carried out as follows.

First, each of the above optical recording media is irradiated with a semiconductor laser (laser beam diameter: 1 scale, irradiation time: 200 ns/1 dot, output 3 mW) with a wavelength of 830 layers according to the recorded information to form a latent image. Formed. that time,
No apparent change was observed in the light irradiated area of each optical recording medium.

Next, after writing by this semiconductor laser was completed, each optical recording medium was uniformly and sufficiently irradiated with ultraviolet rays having a wavelength of 254 nm. Then, the area other than the area irradiated with the semiconductor laser during writing at the end of the recording layer of each optical recording medium changes color to blue, and the latent image formed earlier, that is, the negative where the area irradiated with the semiconductor laser is white, becomes blue. The image was made visible.

The evaluation of the recorded results is shown in Table 1A. The evaluation was based on a comprehensive evaluation of the sensitivity, image resolution, and contrast between the white part and the surrounding area, and a particularly good one was given O1, a good one was given a 0, and one that could not be recorded or was bad was given a ×.

Example 2 An optical recording medium was prepared in the same manner as in Example 1, except that the amount of the diacetylene derivative compound was 1 part by weight and the amount of the croconic methine dye was 10 parts by weight.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
The negative image was visualized by uniformly and sufficiently irradiating it with 54n+s ultraviolet rays, and this was evaluated. The results are shown in Table 1A.

Example 3 An optical recording medium was prepared in the same manner as in Example 1, except that the amount of diacetylene derivative compound was 1 part by weight and the amount of croconic methine dye was 5 parts by weight.

for each of the optical recording media thus obtained.

After performing optical recording in the same manner as in Example 1, each optical recording medium was uniformly and sufficiently irradiated with 254 layers of ultraviolet rays to visualize a negative image, and this was evaluated. The results are shown in Table 1A.

Example 4 The amount of diacetylene derivative compound was 1 part by weight, Crocony
An optical recording medium was prepared in the same manner as in Example 1, except that the total amount of cumetine dye was 1 part by weight.

for each of the optical recording media thus obtained.

After performing optical recording in the same manner as in Example 1, each optical recording medium was uniformly and sufficiently irradiated with 254 layers of ultraviolet rays to visualize a negative image, and this was evaluated. The results are shown in Table 1A.

Example 5 An optical recording medium was prepared in the same manner as in Example 1, except that the amount of the diacetylene derivative compound was 5 parts by weight, and the amount of the lyloconic methine dye was 1 part by weight.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
A negative image was visualized by uniformly and sufficiently irradiating it with 54 nm ultraviolet rays, and this was evaluated. The results are shown in Table 1B.

Example 6 An optical recording medium was prepared in the same manner as in Example 1, except that the amount of diacetylene derivative compound was 10 parts by weight and the amount of croconic methine dye was 1 part by weight.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
The negative image was visualized by uniformly and sufficiently irradiating it with 54 nm ultraviolet rays, and this was evaluated. The results are shown in Table 1B.

Example 7 An optical recording medium was produced in the same manner as in Example 1, except that the amount of diacetylene derivative compound was 15 parts by weight and the amount of croconic methine dye was 1 part by weight.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
The negative image was visualized by uniformly and sufficiently irradiating it with 54 nm ultraviolet rays, and this was evaluated. The results are shown in Table 1B.

Table 1B Examples 8 to 14 After optical recording and visualization of negative images were carried out in the same manner as in Examples 1 to 7, each optical recording medium was heated to about 80°C to remove the blue background. A negative image changed to red was obtained.

The results of evaluating this negative image using the same criteria as in Example 1 are shown in Tables 2A and 2B.

Table 2A Table 2B Example 15 General formula CI2 H2s-C= C-CmiC-Co Hl
The same method as in Example 4 was used except that a compound represented by the general formula Ca H+ 7-CiC-CEC-C2H4-C0OH was used instead of the diacetylene derivative compound represented by b-C0OH. An optical recording medium was created.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
The negative image was visualized by uniformly and sufficiently irradiating it with 54 nm ultraviolet rays, and this was evaluated. The results are shown in Table 3A.

Examples 16-19 Example 15 except that instead of the croconic methine dye represented by Dye-1A/L6, the croconic methine dye represented by Dye-14.24.35.39 was used individually. An optical recording medium was prepared in the same manner as described above.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, 2 discs are recorded on 6 optical recording media.
The negative image was visualized by uniformly and sufficiently irradiating it with 54 nm ultraviolet rays, and this was evaluated. The results are shown in Table 3A and 3.
It is shown in Table B.

Table 3A Table 3B Example 20 A coating solution was prepared by dissolving 10 parts by weight of a croconic methine dye represented by dye acid 6 in 20 parts by weight of methylene chloride.

Next, a glass disc substrate (thickness 1.5 mm, diameter 200 am) was mounted on a spinner coater, and a small amount of the above coating liquid was dropped onto the center of the disc substrate, and then the coating was applied at a predetermined rotation speed. It was applied by rotating a time spinner and dried at room temperature to form a layer containing the croconic methine dye on the substrate.

After forming a layer containing croconic methine dye in this way, C,2H25-C=C-C=C-C8H,6-
DA compound represented by C0OH was dissolved in chloroform 3X.
IO-3 mol/1. The pH of the solution is 6.
．． 5 and developed on an aqueous phase with a cadmium chloride concentration of lXl0-3 mol/l. After removing the solvent chloroform,
While keeping the surface pressure constant, the above-mentioned glass substrate, on which a layer containing a croconic methine dye is formed, whose surface has been sufficiently washed, is moved at a vertical speed of 1.
The monomolecular film of the OA compound was transferred to the surface of the layer containing the croconic methine dye by gently moving it up and down at a rate of 0 c/min.
An optical recording medium was prepared in which a monomolecular film of compound A or a predetermined cumulative number of monomolecular films of this monomolecular film was formed on a layer containing a croconic methine dye.

The thickness of the layer containing the croconic methine dye and the cumulative number of the above monolayers were varied as shown in Table 4A, and the samples were treated with 25 types of light from /L 20-1 to 20-25. Obtained a recording medium.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
The negative image was visualized by uniformly and sufficiently irradiating it with 54n11 ultraviolet rays, and this was evaluated. The results are shown in Table 4B.

Example 21 General formula CI2 H25-C: C-tj C-C,H,
Instead of the diacetylene derivative compound represented by 6-C:00H, a diacetylene derivative compound represented by the general formula CIl)II 7'-C3C-CmiC-C,H4-C:OOH was used. Samples 21-1 to 21-2 as shown in Table 5A were prepared in the same manner as in Example 20, except that
25 kinds of optical recording media of No. 5 were obtained.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
The negative image was visualized by uniformly and sufficiently irradiating it with 54 nm ultraviolet rays, and this was evaluated. The results are shown in Table 5B.

Example 22 Except that a croconic methine dye represented by Dye 酅2 was used instead of a croconic methine dye represented by 6G in the coating solution for forming a layer containing a croconic methine dye. Samples as shown in Table 6A, /122-1 to 22-25 were prepared in the same manner as in Example 21.
25 types of optical recording media were obtained.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
The negative image was visualized by uniformly and sufficiently irradiating it with 54 nm ultraviolet rays and evaluated.6 The results are shown in Table 6B.

Example 23 This was carried out except that a croconic methine dye represented by Dye 29 was used instead of a croconic methine dye represented by Dye 6 in the coating solution for forming a layer containing a croconic methine dye. By the same method as in Example 21, 25 types of optical recording media, Samples/i 23-1 to 23-25, as shown in Table 7A were obtained.

Example 1 was applied to each of the optical recording media thus obtained.
After performing optical recording in the same manner as above, two
The negative image was visualized by uniformly and sufficiently irradiating it with 54 nm ultraviolet rays, and this was evaluated. The results are shown in Table 7B.

[Brief explanation of drawings]

FIG. 1(A), FIG. 1(B), FIG. 2(A), and FIG. 2(B) are schematic cross-sectional views illustrating one aspect of the structure of an optical recording medium used in the method of the present invention, respectively; Figure 3 (A) - 3rd
FIG. 4(C) and FIGS. 4(A) to 4(C) are schematic cross-sectional views of an optical recording medium showing the optical recording process of the present invention. 12 substrates 2: Recording layer 2a: Layer 2b containing DA compound + Layer 3 containing croconicmethine dye: Light irradiation area 4: Laser beam 5a: Latent image 5b: Non-irradiation area 6a: White area 8b: Discoloration area 7 : Croconic methine dyes 8: DA compound

Claims (1)

[Scope of Claims] 1) An optical recording medium having a recording layer comprising a monomolecular film of a diacetylene derivative compound having at least a hydrophilic site and a hydrophobic site or a cumulative film thereof, and a croconic methine dye. a step of irradiating infrared rays of 800 to 900 nm according to the recorded information to form a latent image; and a step of irradiating the optical recording medium on which the latent image is formed with ultraviolet rays to make the latent image visible. An optical recording method comprising: 2) The optical recording method according to claim 1, further comprising a step of heating the optical recording medium after the step of irradiating the optical recording medium with ultraviolet rays.