JPS62174192A - Optical recording method - Google Patents

Abstract

PURPOSE:To enable three-value recording, to provide high density and high orderliness to the constitutional part of a recording layer and to form a recording layer so as to have good homogeneity and a good surface property, by irradiating an optical recording medium having a specific recording layer with ultraviolet rays and subsequently irradiating the same with beam of which the light exposure is controlled corresponding to recording information and discoloring an exposed part with light exposure Q1 and forming a pit comprising a recessed part to an exposed part with light exposure Q2. CONSTITUTION:Ultraviolet rays are allowed to irradiate an optical recording medium having a monomolecular film of a diacetylene derivative having both of hydrophilic and hydrophobic areas or a built-up film thereof and a recording layer containing a chroconic methine dye and, subsequently, beam of which the light exposure is controlled corresponding to recording information is allowed to irradiate said recording medium not only to discolor an exposed part with light exposure Q1 but also to form a pit comprising a recessed part to an exposed part with light exposure Q2. The diacetylene derivative DA is a compound wherein 1, 4-addi tion polymerization reaction can be performed between CidenticalC-CidenticalC-C functional groups of adjacent molecules and a compound represented by general formula I (wherein X is a hydrophilic group forming a hydrophilic area and m and n are an integer) is designated as a representative one. The chroconic methine dye used in this invention is a compound having a structural formula II (wherein M<+> is a group referred to hereinbelow and A<1> and A<2> are a substituent containing an aromatic ring and/or a heterocyclic ring) (also containing an intramolecular salt).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical recording method using an optical recording medium, and in particular to a method that enables a combination of color change recording and pit recording, that is, ternary recording, on one optical disc. The present invention relates to an optical recording method that enables high-density, high-sensitivity optical recording even when using a low-output semiconductor laser, and is advantageous in terms of energy saving.

[Conventional technology]

Recently, optical recording media such as optical disks, optical tapes, and optical cards (hereinafter collectively referred to as optical disks) have been attracting attention as central players in office automation. For example, optical discs can store a large amount of documents and literature on a single disc, so they can be used to organize documents in offices, etc.
It has the advantage that management can be carried out efficiently.

The recording layer used in such optical disc technology can store high density information using optically detectable small dots (eg, one scale) in the form of spiral or circular tracks.

A typical disk used in this optical disk technology is one in which a recording layer made of a material sensitive to laser is provided on a substrate. To write information on this disc, a laser beam focused on the laser sensitive layer (recording layer) is scanned, dots are formed only on the surface irradiated with the laser beam, and the dots are shaped into a spiral or circular shape depending on the recorded information. Form in the form of a track. That is, the laser sensitive layer is capable of absorbing laser energy to form optically detectable dots. For example, in the heat mode recording method, the laser-sensitive layer absorbs thermal energy and can form dots consisting of small recesses (pits) at that location by evaporation or melting. In another heat mode recording method, the absorption of irradiated laser energy can form a dot of optically detectable discoloration at that location.

Information recorded on this optical disk is detected by scanning a laser along a track and reading optical changes in areas where dots are formed and areas where dots are not formed. For example, when using a disk with a recording layer provided on the reflective surface of a substrate, a laser is scanned along a track and the energy reflected by the disk is monitored by a photodetector. At this time, in the case of pit recording, the output of the photodetector decreases in areas where pits are not formed, while in areas where pits are formed, the laser beam is sufficiently reflected by the underlying reflective surface and the photodetector output is reduced. output becomes larger.

Various types of recording layers for such optical discs have been studied, including those mainly using inorganic materials such as metal thin films such as aluminum evaporated films, bismuth thin films, tellurium oxide thin films, and chalcogenide amorphous glass films. However, recently, organic materials have been attracting attention due to their cost and ease of manufacture.

On the other hand, since the conventional heat mode method performs binary recording of whether dots are formed or not, there is a limit to the ability to perform higher density recording.

[Problem that the invention seeks to solve]

The present invention has been made to solve the problems of the prior art, and by forming the recording layer of an optical recording medium by combining a croconic methine dye and a diacetylene derivative compound, it is possible to form a single optical disc. Color change recording and pit recording are possible, that is, 3 types of dots with 2 types are possible.
It was developed based on the discovery that it is possible to record values, and even when using a low-output semiconductor laser, color change recording and pit recording can be performed at comparable high speeds.

An object of the present invention is to provide an optical recording method that enables three-value recording using two types of dots on one disc.

Another object of the present invention is to provide an optical recording method that enables optical writing using a small, lightweight, and low-output semiconductor laser and also enables high-speed recording.

Another object of the present invention is to provide an optical recording method that allows recording with higher density and higher sensitivity.

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 is an optical recording method having a recording layer containing 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. The recording medium is irradiated with ultraviolet rays, and then irradiated with light whose exposure amount is controlled according to the recorded information, discoloring the exposed area of the exposure amount Q,
The exposed portion of No. 2 is characterized by having a step of forming a pit consisting of a concave portion (however, Q+ < Q2).

The diacetylene derivative compound having both a hydrophilic site and a hydrophobic site (hereinafter abbreviated as DA compound) used in the present invention means that the C:C-CEC-G functional groups in adjacent molecules have a 1.4- It is a compound capable of addition polymerization reaction, and typically has the following general formula (%) (wherein, X is a hydrophilic group forming a hydrophilic site,
m and n represent integers. ) Compounds represented by:

Examples of the hydrophilic group X in the above DA compound include a carboxyl group, an amine group, a hydroxy group, a nitrile group,
Examples thereof include a thioalcohol group, an imino group, a sulfonic acid group, a sulfinyl group, or a metal or amine salt thereof. The alkyl group represented by H(CH2)11 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 structural formula: (M: described below, A1, A2: substituent containing aromatic ring and/or heterocycle) 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 croconic methine dyes typically have the following general formulas [I] to [r
V] is exemplified.

General formula [II] General formula [II] General formula [I11] General formula [IV] -propyl group, 1
so-propyl group, n-butyl group, 5ec-butyl group,
1so-butyl group, t-butyl group, n-amyl group, -
amyl 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-acetoxyethyl group, carboxy Methyl group, 2-carboxyethyl group, 3-carboxypropyl group, 2-sulfoethyl group, 3-sulfopropyl group, 4-
Sulfobutyl group, 3-sulfatepropyl group, 4-sulfatebutyl group, N-(methylsulfonyl)-carbamylmethyl group, 3-(acetylsulfamyl)propyl group, 4-(acetylsulfamyl)butyl group Such)
, a cyclic alkyl group (e.g., cyclohexyl group, etc.),
Allyl group, aralkyl group (e.g., benzyl group, phenethyl group, α-naphthylmethyl group, β-naphthylmethyl group, etc.), substituted aralkyl group (e.g., carboxybenzyl group, sulfobenzyl group, hydroxybenzyl group, etc.)
, represents an aryl group (eg, phenyl group, etc.) or a substituted aryl group (eg, carboxyphenyl group, sulfophenyl group, hydroxyphenyl group, etc.). In particular, in the present invention, among these organic residues, hydrophobic ones are preferred.

Substituted or unsubstituted heterocycles, e.g. thiazole series nuclei (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-bromobenzothiazole, 5-phenylbenzothiazole, 5-methoxybenzothiazole, 6-methoxybenzothiazole, 5
．． 6-dimethoxydibenzothiazole, 5,6-cyoxymethylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, 4,5,6
．． 7-titrahydropenzothiazole, etc.), naphthothiazo-1-1 series, roasted 1-bit powder;・[2,1-d
J thiazole, naphtho[1,2-d]thiazole, 5-
Methoxynaphtho[1,2-d]thiazole, 5-ethoxynaphtho[1,2-d]thiazole, 8-methoxynaphtho[2,1-d]thiazole, 7-methoxynaphtho[2
, 1-d]thiazole, etc.), thionaphthene[7,6-
d] Thiazole series nuclei (e.g. 7-medoxythionaphthene[7,6-d]thiazole), oxazole series nuclei (e.g. 4-methyloxazole, 5-methyloxazole, 4-phenyloxazole, 4,5-diphenyl) oxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole), benzoxazole series nuclei (e.g. benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, 6- methylbenzoxazole, 5,6-dimethylbenzoxazole, 5-methoxybenzoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphtho-oxazole series nuclei (e.g. naphtho[2, 1-
d]oxazole, naphtho[1,2-d]oxazole, etc.), selenazole series nuclei (e.g. 4-methylselenazole, 4-phenylselenazole, etc.), benzoselenazole series nuclei (e.g. benzoselenazole, 5-
Chlorobenzoselenazole, 5-methylbenzoselenazole, 5.6-dimethylbenzoselenazole, 5-methoxybenzoselenazole, 5-methyl-6-methoxybenzoselenazole, 5.6-cyoxymethylenebenzoselenazole , 5-hydroxybenzoselenazole, 4.
5,6,7-titrahydropenzoselenazole, etc.),
Nuclei of the naphthoselenazole series (e.g. naphtho[2,1-
d] selenazole, naphtho[1,2-d]selenazole), thiazoline series nuclei (e.g. thiazoline, 4-methylthiazoline, 4-hydroxymethyl-4-methylthiazoline, 4,4-bis-hydroxymethylthiazoline, etc.), oxazoline series core (e.g. oxazoline)
, a nucleus of the selenazoline series (e.g. selenazoline), 2-
Quinoline series nuclei (e.g. quinoline, 6-methylquinoline, 6-chloroquinoline, 6-medoxyquinoline, 6-
nitoxyquinoline, 6-hydroxyquinoline), 4-quinoline series nuclei (e.g. quinoline, 6-medoxyquinoline, 7-methylquinoline, 8-methylquinoline), 1-
Nuclei of the isoquinoline series (e.g. isoquinoline, 3.4-
dihydroisoquinoline), 3-isoquinoline series nuclei (
(e.g. inquinoline), 3,3-dialkylindolenine series nuclei (e.g. 3,3-dimethylindolenine,
3.3-dimethyl-5-chloroindolenine, 3,3.
5-trimethylindolenine, 3,3,7-4lymethylindolenine), pyridine series nuclei (e.g. pyridine,
5-methylpyridine), benzimidazole series nuclei (
For example, 1-ethyl-5,6-dichlorobenzimidazole, ■-bitroxyethyl-5,6-dichlorobenzimidazole, 1-ethyl-5-chlorobenzimidazole, 1-ethyl-5,6-dibromobenzimidazole, 1 -ethyl-5-phenylbenzimidazole, 1-
Ethyl-5-fluorobenzimidazole, 1-ethyl-5-cyanobenzimidazole, 1-(β-acetoxyethyl)-5-cyanobenzimidazole, toethyl-5-chloro-6-diatubenzimidazole, 1-ethyl-5 -fluoro-6-cyanobenzimidazole,
1-Ethyl-5-acetylbenzimidazole, 1-ethyl-5-carboxybenzimidazole, ]-ethyl-5-ethoxycarbonylbenzimidazole, ■-ethyl-5-sulfamylbenzimidazole, 1-ethyl-3-N- ethylsulfamylbenzimidazole,
1-ethyl-5,6-difluorobenzimidazole,
]-Ethyl-5,6-dichlorobenzimidazole, 1
-ethyl-5-ethylsulfonylbenzimidazole,
1-ethyl-5-methylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylbenzimidazole, ■-ethyl-5-trifluoromethylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylsulfinylbenzimidazole, etc.) Represents a group of nonmetallic atoms necessary for completion. X is a chloride ion, bromide ion, iodide ion, perchlorate ion,
Benzene sulfonate ion, p-toluene sulfonate ion, methyl sulfate ion, ethyl sulfate ion,
represents an anion such as propyl sulfate ion θ ion, and X represents R1 and/or θ
θ ee -C00,5o2NH-, -302-N-(:0-1-
502-N-802-, does not exist when it is included. M represents a cation such as a hydrogen cation, a sodium cation, an ammonium cation, a potassium cation, or a pyridium cation. n and m are 0 or 1.

In general formula (m) (TV), R3 and R4 are methyl,
Indicates an alkyl group such as ethyl, propyl, butyl. Further, R3 and R4 can also form a ring such as morpholino, piperidinyl, or pyrrolidino together with the nitrogen atom. R5, R6, R7 and RO represent a hydrogen atom, an alkyl group (methyl, ethyl, propyl, butyl, etc.), an alkoxy group (methoxy, ethoxy, propoxy, butoxy, etc.), or a bitroxy group. Further, R5 and R6 can be combined to form a benzene ring, and R5 and R6 can be combined with R7 and 8 to form a benzene ring, respectively.

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

Representative examples of general formula II], [II] Oe・ (8) o0(23)
. e(24)
. e(25). e(2
B). θ general formula [ml, [
IV] Representative example (35) eO (as) e.

(39) C).

(a o ) O0” double layer (1) ~
The croconic methine dyes (42) can be used alone or in combination of two or more.

The optical recording medium used in the wood invention comprises a monomolecular film or a monomolecular cumulative film of the crystalline compound and the croconic methine dye, and may have a one-layer mixed system, a two-layer separated system, or a multilayer laminated system. .

Here, the one-layer mixed system refers to one consisting of a mixed layer of D crystal compound and croconic methine dye, and the two-layer separated system refers to
A system in which a layer containing a D crystal compound and a layer containing a croconic methine dye are separately laminated is further referred to as a multilayer laminated system.
It refers to a structure that does not include the two-layer separation system, in which one or more layers containing a DA crystal compound and one or more layers containing a croconic methine dye are 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.
The configuration in which a mixed monomolecular film of crystalline compound 7 and croconic methine dye 6 is formed is shown in 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. A structure in which DA crystal compound 7 monomolecular films 2a are laminated, Fig. 2 (B)
This is a structure in which a monomolecular cumulative film 2a of DA crystal compound 7 is formed on a layer 2b containing a croconic methine dye.

Note that 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 1 of the optical recording medium used in the wood 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.

DA 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-Prodgett method (hereinafter abbreviated as LB method) developed by Langmuir et al. is used. In the LB method, when a molecule has a parent wood group and a hydrophobic group in its molecule, and the balance between the two (amphipathic balance) is maintained appropriately, this molecule lowers the parent wood group on the water surface. This is a method of creating a monomolecular film or a film made up of monomolecular layers by taking advantage of the fact that the monomolecular layer becomes a layer directed toward the molecule.

A monolayer on the water surface has the characteristics of a two-dimensional system. When the molecules are sparsely dispersed, the area per molecule A and the surface pressure n
The two-dimensional ideal gas equation, nA=kT, holds true, resulting in a "gas film".Here, k is Boltzmann's constant and T is the absolute temperature.If A is made small enough, the intermolecular interaction becomes stronger and becomes a two-dimensional solid °° condensed film (or solid film). 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 hydrophilic site and a hydrophobic site,
Not all compounds are necessarily required to have a hydrophilic moiety and a hydrophobic moiety coexist. In other words, if the amphipathic balance of at least one compound is maintained, a monomolecular layer will be formed on the water surface, and the other compounds will be sandwiched between the amphipathic compounds, resulting in a well-ordered molecular layer as a whole. A monolayer is formed.

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 spread on an aqueous phase to form a spread layer in which these compounds are spread in the form of a film. Next, to prevent this spread layer from spreading freely on the water phase and spreading too much, a partition plate (or float) is provided to limit the area of the spread layer and control the aggregation state of these compounds. J711. Obtain the surface pressure (■) as shown in the example. By moving this partition plate, the developed area can be reduced to control the aggregation state of the film material, and the surface pressure can be gradually increased to set a surface pressure n suitable for producing a cumulative film. By gently raising and lowering a clean substrate vertically while maintaining this surface pressure,
A mixed monolayer of DA compound and croconic methine dye is transferred onto a substrate. A mixed monomolecular layer film is produced in this way, and by repeating the above-mentioned operations, a mixed monomolecular layer film with a desired degree of accumulation of 32° is formed.

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 hydrophilic surface is lifted out of water in a direction transverse to the water surface, a first monomolecular layer is formed on the substrate with the parent group of the DA compound facing the substrate. .

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 in which the parent wood group and the hydrophilic group, and the hydrophobic group and the hydrophobic group face each other between each layer.

On the other hand, the horizontal deposition method is a method in which the substrate is brought into horizontal contact with the water surface and transferred, and a monomolecular layer with the hydrophobic group of the OA compound facing the substrate is formed on the substrate. In this method, there is no change in the orientation of the DA compound molecules even if they are accumulated, and an X-type film is formed in which the hydrophobic groups face the substrate in all layers. On the other hand, a cumulative film in which all the layers have parent groups facing the substrate is called a Z-type 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 variations in light absorption depending on location are extremely small. Therefore, by configuring the recording layer with such a film, recording having high-density and high-resolution recording functions capable of optical recording and thermal recording can be achieved depending on the functions of the D^ compound and the croconic methine dye. A medium 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.

In this case, the layer 2a consisting of a monomolecular film of the formula D compound or a cumulative film thereof is prepared by preparing a developing solution containing the formula D compound (not containing the croconic methine dye) and depositing it on the substrate by the above-mentioned LB method. 1 or on other layers already formed on the substrate 1.

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 onto another layer already formed on the substrate 1. It can be formed by coating to obtain a predetermined dry film thickness and then drying this. or,
By the above-mentioned LB method, using a croconic methine dye and 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 an arbitrary ratio. If it is introduced into a monomolecular film, a monomolecular film or a monomolecular cumulative film 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 isopropanol can be used as the solvent for forming the coating solution. Ketones such as acetone, methyl ethyl ketone, and cyclohexanone: Amides such as N,N-dimethylformamide, ff, and N-dimethylacetamide Sulfoxides such as dimethyl sulfoxide: Ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether;
Examples include esters such as methyl acetate and ethyl acetate, aromatics such as benzene, 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-trichloromethane, chlorobenzene, bromobenzene, 1
, 2-dichlorobenzene and other halogenated hydrocarbons.

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,
Bead coating method, wire bar coating 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 a single-layer mixed type, the film thickness is suitably about 200 to 2u1, and particularly preferably from 400 to 5000. In addition, in the case of a two-layer separation system, the film thickness of each layer is suitable to be about 100 to 1 scale, especially 200 to 5.
A range of 000 people is preferred. Furthermore, in the case of a multilayer laminated system, both the sum of the film thicknesses of the layers containing individual crystal compounds and the sum of the film thicknesses of the layers containing individual croconic methine dyes are:
Approximately 100 to 1 μm is suitable, especially 200 to 5
A range of 000 people is preferred.

The blending ratio of the DA compound and the croconic methine dye in the recording layer 2 is preferably about 1715 to 1571, and optimally about 1/1O to 10/1.

Note that various protective layers may be provided on the recording layer 2 configured as described above, if necessary. Further, the method of the present invention can be carried out regardless of the order in which the layers are laminated in the case of a two-layer separation system or a multilayer laminate system.

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 applying light to the compound of formula D, 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, 620-6
It has a maximum absorption wavelength of 60 nm and changes from blue to 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.

Further, the recording layer containing the polydiacetylene derivative compound and the croconic methine dye, which has changed its color from blue to dark, generates heat at a temperature corresponding to the exposure amount of the irradiated light. At that time, if the recording layer 2 is not melted and the polydiacetylene derivative compound is heated to about 50°C or higher,
The exposed portion of the recording layer has a maximum absorption wavelength of about 540 nm and turns into a red film. Note that this change to a red film is also an irreversible change.

Further, when the exposure amount is increased and the exposure amount exceeds a certain limit, the exposed portion of the recording layer melts.

The optical recording method of the present invention performs recording by utilizing the characteristics obtained by the combination of compound A and croconic methine dye.

This recording method will be explained in detail below.

As the semiconductor laser used in the method of the present invention, it is particularly suitable to use a GaAs junction laser with an output wavelength of 800 to 850 nm.

When carrying out the optical recording method of the present invention, first, the entire recording layer is irradiated with ultraviolet rays. By irradiating this ultraviolet light,
The DA compound in the recording layer is polymerized and changed into a poly- or diacetylene derivative compound, and the recording layer changes color into a blue to dark-colored film.

On the other hand, the recorded information is converted into an optical signal by a semiconductor laser via a 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 ^). The imaging position is the recording layer 2 of the optical recording medium.

The exposure amount at the imaging points (sites) 3a and 3b is sufficient to heat the polydiacetylene derivative compound to about 50° C. or higher for color change recording, and at a temperature that does not melt the recording layer 2 (Qt ) and an amount (Q2 ) sufficient to melt the recording layer 2 for pit recording (
However, Qt < Q2).

In order to change the exposure amount at the imaging point in this way, a method may be used such as changing the intensity of the semiconductor laser, changing the laser irradiation time, or using these in combination. Note that when performing irradiation with two types of exposure doses, the above control may be performed using one semiconductor laser, or multiple semiconductor lasers that can obtain different exposure doses may be used. .

The croconic methine dye present at the imaging points (sites) 3a and 3b absorbs this laser beam 4 and generates heat.

Here, the image forming point 3a that received the exposure amount of Qt mentioned above is
As the polydiacetylene derivative compound is heated by the heat generated by the croconic methine dye, it changes to red color, and as shown in FIG. Become. In addition, in an optical recording medium having a recording layer consisting only of a DA compound, the polydiacetylene derivative compound does not have sensitivity to a laser with a wavelength of 800 to 850 nm, so when a semiconductor laser with this wavelength is used, , optical recording was impossible due to discoloration.

On the other hand, the image forming point 3b that received the above-mentioned exposure amount of Q2 melts due to the heat generated by the croconic methine dye.
As shown in FIG. 3(B), a pit consisting of a recess 5b is formed.

In this case, since the recording layer 2 of the optical recording medium used in the present invention is constituted by a combination of a croconic methine dye and a polydiacetylene derivative compound as described above, that is, due to the presence of a polydiacetylene derivative compound, The energy required for melting the recording layer can be significantly reduced, and pit formation by the croconic methine dye is greatly promoted.

In this way, the discolored portion 5a is formed on the recording layer 2 according to the manual information.
Optical recording using two different types of dots, ie, ternary recording, is carried out using dots having two different shapes, ie, the pits 5b and 5b. Moreover, since the optical recording medium used in the present invention has high sensitivity to both color change recording and pit recording, such ternary recording can be performed at high speed.

The case where an optical recording medium having a single mixed recording layer is used has been described above, and FIGS. 2(8) and 2(B)
When using a two-layer separation system as shown in
A and 3b are layers 2b containing croconic methine dye, as shown in FIG. 4(A).

When the laser 4 is irradiated in this way, the exposure amount Q1. The croconic methine dye generates heat in response to Q2, and as shown in FIG. 4(B), dots 5a consisting of discolored areas or pits 5 consisting of concave areas
b is formed.

The two types of dots recorded in the above manner can be read both at once or only one of them, as desired.

In the above example, a disk-shaped disk (optical disk) was used as the optical recording medium, but of course, depending on the type of substrate that supports the recording layer containing the DA 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 croconic methine dye and diacetylene derivative compound is used in the recording layer, desired discoloration recording and pit recording can be performed on one recording medium using a small and lightweight semiconductor laser. You can do it accordingly. That is, high-density recording by ternary recording is possible with one recording medium. Moreover, the recording layer has high sensitivity in both color change recording and pit recording, and high-speed recording is possible.

(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,
Excellent stability and high quality optical recording 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 CI2 H2S-C” C-Cmi c-c8H,6
A solution prepared by dissolving 1 part by weight of a diacetylene derivative compound represented by ``-co'' and 15 parts by weight of a croconic methine dye represented by dye MFL6 in chloroform at a concentration of 3 x 10-3 mol/1 was prepared at a pH of 6. 5, the cadmium chloride concentration is lX1O-3 mol/! was developed on the aqueous phase. After removing the solvent chloroform, while keeping the surface pressure constant, the glass substrate whose surface had been thoroughly cleaned was gently lowered across the water surface at a vertical speed of 1.0 cm for 7 minutes to remove the DA compound. A mixed monomolecular film of and croconic methine dye is transferred onto a substrate to create an optical recording medium in which a mixed monomolecular film and a mixed monomolecular cumulative film of 21, 41, or 81 layers are formed on the substrate. did.

Each of the optical recording media obtained in this way was first given 25
The recording layer was uniformly and sufficiently irradiated with ultraviolet rays having a wavelength of 4 nm to turn the recording layer into a blue film.

Next, a semiconductor laser with a wavelength of 830 nm whose laser output can be varied (maximum ratio 10 m1, laser beam diameter: 1 door, irradiation time: 200 ns) is applied to each optical recording medium having this blue film recording layer. / 1 dot)
was irradiated according to the recorded information to carry out the optical recording of the present invention. In addition, when pit recording command is issued, the laser output is set to 8.
mW, and when the color change recording command is issued, the laser output is 4 mW.
It was set as W.

Table 1 shows the evaluation of the recording results. The evaluation is based on a comprehensive evaluation of sensitivity, resolution, and contrast ratio between recorded and non-recorded areas for recording both pits and discoloration. Particularly good is ◎, good is ○, and recording is not possible or not possible. Bad items were marked as ×.

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.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 1.

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.

Each of the optical layer i media thus obtained was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 1.

Example 4 An optical recording medium was produced 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 1 part by weight.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 1.

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

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating the recording layer with 4 nm ultraviolet rays to turn the recording layer into a blue film, optical recording was carried out in the same manner as in Example 1, and this was evaluated. The results are shown in Table 1.

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.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 1.

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.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 1.

bu Example 8 General formula C,,H25-C::C-CmiGC:8H16
In place of the diacetylene derivative compound represented by -Go, general formula 〇8H,, -C3C-C3C-C,H4-Go
Example 4 except that a compound represented by a leaf was used.
An optical recording medium was prepared in the same manner as described above.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 2.

Examples 9 to 12 In place of the croconic methine dye represented by dye description 6,
Optical recording media were prepared in the same manner as in Example 8, except that dyes A and croconic methine dyes represented by I4.24.35.39 were used individually.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 2.

Example 13 Dye Croconic methine dye 1 represented by IFL6
A coating solution was prepared by dissolving 0 parts by weight in 20 parts by weight of methylene chloride.

Next, a glass disc substrate (thickness: 1.5 mm, diameter: 200 mm) was mounted on a spinner coating machine, 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 number of rotations. 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 the layer containing the croconic methine dye in this way, C,2H25-C:(nee[1:miC-C3
A solution of a DA compound represented by H16-COOH dissolved in chloroform at a concentration of 3 x 10-3 mol/1 was
It was developed on an aqueous phase with a H of 6.5 and a cadmium chloride concentration of 1×10 −3 mol/1. After removing the solvent chloroform, while keeping the surface pressure constant, the glass substrate on which the layer containing the croconic methine dye, whose surface had been thoroughly cleaned, was formed was moved in a vertical direction transverse to the water surface at a speed of 1.
．． The monomolecular film of the DA compound was transferred to the surface of the layer containing Crofnick methine dye by gently moving it up and down for 0 cm for 7 minutes.
An optical recording medium was prepared in which a monomolecular film of a DA compound or a monomolecular cumulative film obtained by accumulating a predetermined number of such monomolecular films 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 monolayers were varied as shown in Table 3, and 25 types of optical recording media of samples AIIL13-i to 13-25 were used. Obtained.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 4.

4th Example 14 General formula C,,H25-C:C-C-CBH,6-C0
Instead of the diacetylene derivative compound represented by OH,
Sample A as shown in Table 5 was prepared in the same manner as in Example 13, except that a diacetylene derivative compound represented by the general formula c8H17-c=c-c=c-c2H4-co was used. 25 types of optical recording media named 4-1 to 14-25 were obtained.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating the recording layer with 4 nI[l of ultraviolet light to turn the recording layer into a blue film, optical recording was carried out in the same manner as in Example 1, and this was evaluated. The results are shown in Table 6.

Example 15 Except that a croconic methine dye represented by Dye Sei 2 was used instead of a croconic methine dye represented by Dye Sei 6 in the coating solution for forming a layer containing croconic methine dyes. Samples A11L15-1 to 15-25 as shown in Table 7 were prepared in the same manner as in Example 14.
25 types of optical recording media were obtained.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating with 4 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 8.

Example 16 Except that a croconic methine dye represented by Dye J/IL29 was used instead of a croconic methine dye represented by Dye Sei 6 in the coating solution for forming a layer containing croconic methine dyes. Samples/a 1 B -1 to 1 as shown in Table 9 were prepared in the same manner as in Example 14.
6-25, 25 types of optical recording media were obtained.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating the recording layer with 4nI11 ultraviolet rays to turn the recording layer into a blue film, optical recording was carried out in the same manner as in Example 1, and this was evaluated. The results are shown in Table 10.

Table 10

[Brief explanation of drawings]

FIG. 1(^), 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. FIGS. 3(8) and 3(B) and FIGS. 4(A) and 4(B) are schematic cross-sectional views of an optical recording medium showing the optical recording process of the present invention, respectively. 1: Substrate 2: Recording layer 2a: Layer containing DA compound 2b = Layer containing croconic methine dye 3a, 3b = Exposure section 4: Laser beam 5a: Discoloration section 5b - Pit 6: Croconic methine dye 7: Diacetylene derivative compound

Claims (1)

[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 is irradiated with ultraviolet rays. Next, a step of irradiating light with the exposure amount controlled according to the recorded information, discoloring the exposed area with the exposure amount Q_1, and forming a pit consisting of a concave part in the exposed area with the exposure amount Q_2 (however, Q_1<Q_2) An optical recording method characterized by having the following.