JPS62174193A - Optical recording method - Google Patents

Abstract

PURPOSE:To enable not only optical writing but also high speed recording by small-sized light wt. low output semiconductor layer, by irradiating an optical recording medium having a specific recording layer with beam corresponding to recording information. CONSTITUTION:A beam is allowed to irradiate an optical recording medium having a recording layer containing a polydiacetylene derivative and a chroconic methine dye corresponding to recording information. The recording information is converted to an optical signal by semiconductive laser through a control circuit and said optical signal is formed into an image at the predetermined position of the optical recording medium through an optical system. The image forming position is present in the recording layer 2 of the optical recording medium. The chroconic methine dye present at the image forming point 3 absorbs laser beam 4 to generate heat and the recording layer 2 of the image forming pint 3 is melted to be formed into a pit comprising a recessed part 5. By the presence of the polydiacetylene derivative, the formation of the above- mentioned pit due to the chroconic methine dye is promoted to a large extent.

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 high-density, high-sensitivity, high-speed pit recording even when using a low-output semiconductor laser. The present invention relates to an optical recording method that is possible and 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 have the advantage of being able to record and store a large amount of documents, documents, etc. on a single disc, allowing for efficient organization and management of documents, etc. in an office.

The recording layer used in such optical disk technology can store high-density information by forming optically detectable small dots (for example, about 1 μl) 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 pits due to evaporation or melting at that location. Another heat mode recording method is to absorb the applied laser energy, thereby forming a dot with an optically detectable discolored area.

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 (in this case, 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 is The output of the detector 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, products using organic materials are attracting attention due to their cost and ease of manufacture.

As an organic material used for optical recording media, Japanese Patent Application Laid-Open No. 58-1
Croconic methine dyes are disclosed in No. 81052 and Japanese Patent Application Laid-Open No. 59-60443, and organic coatings containing these dyes absorb radiation in the semiconductor laser radiation wavelength region and generate heat, so pits can be formed using laser energy. It is known that it is possible to carry out so-called heat mode recording.

[Problem that the invention seeks to solve]

However, although the conventional pit recording method has the advantage of clear recording, that is, good contrast, it requires more energy for recording and has a lower recording speed than the recording method that forms dots through discoloration. The disadvantage was that it was slow. Furthermore, since physical pits are formed on the surface of the recording medium, it is necessary to ensure that the initial surface of the recording medium is sufficiently smooth and at the same time, sufficient care must be taken to avoid scratching the surface of the recording medium even after recording. At the same time, it was difficult to perform high-density, high-sensitivity recording.

For example, when the recording layer of an optical recording medium is formed from the above-mentioned croconic methine dye, the croconic methine dye absorbs a semiconductor laser beam (infrared rays) and generates heat, and as a result of the heat generation, it self-melts, so this characteristic is This can be used to form pits on optical recording media. However, it requires a large amount of energy to form pits, has low sensitivity, and requires a relatively long exposure (light irradiation) time - longer than a window. Therefore, it was not possible to shorten the exposure time and recording at higher speeds was not possible.

The present invention has been made to solve the problems of the prior art, and the present inventors have developed a method by forming a recording layer of an optical recording medium by combining a croconic methine dye and a diacetylene derivative compound. They have discovered that the pit formation rate under light irradiation is significantly accelerated even when a low-power semiconductor laser is used, and have completed the present invention.

An 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 capable of recording at high density and high 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.
There it is.

[Means for solving problems]

That is, the optical recording method of the present invention provides recording information on an optical recording medium having a recording layer containing a polydiacetylene derivative compound and a croconic methine dye. The method is characterized by comprising a step of forming a dot consisting of a recessed portion.

The method of the present invention (the diacetylene derivative compound (hereinafter abbreviated as OA compound) contained in the optical recording medium to be used) has the following general formula R-CE C-CE C-R' (wherein R and R ' is a polar group: an alkyl group, a saturated aliphatic hydrogen group such as a cyclohexyl group, which may be substituted with a polar group: a vinyl group, which may be substituted with a polar group,
A phenyl group, a naphthyl group, which may be substituted with an olefinic hydrocarbon group such as a propenyl group or a polar group,
An aromatic hydrocarbon group such as an alkylphenyl group,
Examples of the polar group here include a carboxyl group or a metal or amine salt thereof, a sulfonic acid group or a metal or amine salt thereof, a sulfamide group, an amide group, an amino group, an imino group, a hydroxy group, an oxyamino group, a diazonium group, Examples thereof include a guanidine group, a hydroxy group, a phosphoric acid group, a silicic acid group, an aluminate group, a nitrile group, a thioalcohol group, a nitro group, and a halogen atom. ) and their polymers.

Furthermore, as will be described later, in the case where the recording layer is formed from a monomolecular film or a monomolecular cumulative film, the OA compound has a 1°4-
A compound capable of addition polymerization reaction, typically the following general formula (%) (wherein, X is a hydrophilic group forming a hydrophilic site,
m and n represent integers. ) is included.

Examples of the hydrophilic group X in this case include a carboxyl group, an amino group, a hydroxy group, a nitrile group, a thioalcohol group, an imino group, a sulfonic acid group, a sulfinyl group, or a metal or amine salt thereof. H(CH2)I! forms a hydrophobic site! The alkyl group represented by 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 an inner salt) having the following basic structure: And (80
It is a compound that has absorption in the wavelength range of 0 to 900 nm and generates heat when exposed to infrared light of this wavelength. The croconic methine dyes typically have the following general formulas [I] to [I
V] is exemplified.

General formula [■ General formula [11] General formula [■ General formula [IV] O In general formulas (I) and (II), R1 and R2 are an alkyl group (for example, a methyl group, an ethyl group, a propyl group) , 1s
o-propyl group, Kanobutyl group, 5ec-butyl group, is
Butyl group (t-butyl group, n-amyl group, t-amyl group, n-hexyl group, n-octyl group, -octyl group), substituted alkyl group (e.g. 2-hydroxyethyl group, 3-hydroxy Propyl group, 4-hydroxybutyl group, 2-acetoxyethyl group, carboxymethyl 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 base,
4-(acetylsulfamyl)butyl group), cyclic alkyl group (e.g., cyclohexyl group, etc.), allyl group, aralkyl group (e.g., benzyl group, phenethyl group,
α-nanotylmethyl group, β-naphthylmethyl group, etc.),
Substituted aralkyl groups (e.g. carboxybenzyl group, sulfobenzyl group, hydroxybenzyl group), aryl groups (e.g. phenyl group) or substituted aryl groups (e.g. carboxyphenyl group, sulfophenyl group, etc.)
hydroxyphenyl group, etc.). In particular, in the present invention, among these organic residues, hydrophobic ones are preferred.

Substituted or unsubstituted heterocycles, for example nuclei of the thiazole series (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-methoxyhendithiazole, 6-methoxyhendithiazole, 5
, 6-dimethoxyhenzothiazole, 5.6-cyoxymethylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, 4.5,6
．． 7-titrahydrohenzothiazole, etc.), naphthothiazole series nuclei (e.g. naphtho[2,1-d]thiazole, naphtho[1,2-d]thiazole, 5-methoxynaphtho[L2-d]thiazole, 5-ethoxy Naft [
1,2-d]thiazole, 8-methoxynaphtho[2,1
-d]thiazole, 7-methoxynaphtho[2,1-dl
thiazole), thionaphthene[7,6-d]thiazole series nuclei (e.g. 7-medoxythionaphthene[7,6-d]
6-d]thiazole), 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-dimethyl] 2 benzoxazole, 5-methoxybenzoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphtho Nuclei of the oxazole series (e.g. naphtho [
2,1-d]oxazole, nand[1,2-d]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-methoxyhexoselenazole, 5.6-cyoxymethylenebenzoselenazole, 5-hydroxybenzoselenazole, 4.5,6.7-titrahydrohenzoselenazole, 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 nuclei (e.g. oxazoline), selenazoline series nuclei (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-isoquinoline series nuclei (e.g. isoquinoline, 3
．． 4-dihydroisoquinoline), 3-isoquinoline series nuclei (e.g. isoquinoline), 3.3-dialkylindolenine series nuclei (e.g. 3,3-dimethylindolenine, 3,3-dimethyl-5-chloroindolenine, 3
, 3,5-trimethylindolenine, 3,3,7-trimethylindolenine), pyridine series nuclei (e.g. pyridine, 5-methylpyridine), benzimidazole series nuclei (e.g. 1-ethyl-5,6-dichloro Benzimidazole, 1-hydroxyethyl-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, 1
-ethyl-5-chloro-6-cyanobenzimidazole, 1-ethyl-5-fluoro-6-cyanobenzimidazole, 1-ethyl-5-acetylbenzimidazole, 1-ethyl-5-carboxybenzimidazole, 1
-ethyl-5-ethoxycarbonylbenzimidazole, 1-ethyl-5-sulfamylbenzimidazole,
1-ethyl-3-N-ethylsulfamylbenzimidazole, 1-ethyl-5,6-difluorobenzimidazole, 1-ethyl-5,6-dichlorobenzimidazole, 1-ethyl-5-ethylsulfonylbenzimidazole, 1-ethyl-5-methylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylbenzimidazole, 1-ethyl-5-trifluoromethylsulfonylbecizimidazole, 1-ethyl-5-trifluoromethylsulfinylbenzimidazole, etc. ) represents the nonmetallic atomic group necessary to complete the process. X is chloride ion, bromide ion, iodide ion, perchlorate ion, benzenesulfonate ion, p-toluenesulfonate ion, methyl sulfate ion, ethyl sulfate ion, propyl sulfate ion θ ion represents an anion such as, X represents R1 and /mae
e θ θ -C00, SO2NH-, -5O2-N-CO-2-3
O2-N-3O2-, 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 O or 1.

In general formula (III) (rV), R3 and R4 are
Indicates an alkyl group such as methyl, 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 R8 are hydrogen atoms, alkyl groups (methyl, ethyl, propyl, butyl, etc.),
Indicates an alkoxy group (methoxy, ethoxy, propoxy, butoxy, etc.) or a hydroxy group. Also, R5 and R6
can be combined to form a benzene ring, and roughly R
5 and R6 can be combined with R7 and R8 to form a benzene ring.

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

Representative examples of general formula [I], [11] GIV, Lid (23). θ(24)
. e(25)
. e(27)oe Representative example (35)e of general formula [ml], [IV].

(36) θ.

(37) θ.

(39) C’.

(40) e0 The chronic methine dyes of (1) to (42) above are 1f
! Alternatively, two or more types can be used in combination.

A typical configuration of an optical recording medium used in the present invention is shown in FIG. 1. In this example, a recording layer 2 containing the OA compound and a croconic methine dye is provided on a substrate 1.

The recording layer 2 of the optical recording medium used in the present invention is the OA
A coating solution is prepared by mixing a fine crystalline powder of a DA compound and a croconic methine dye in a suitable volatile solvent. on the substrate, or
It can be obtained by a method such as forming a mixed monomolecular film or a mixed monomolecular cumulative film of an OA compound and croconic methine dye on a substrate.

As the substrate 1 of the optical recording medium used in the present invention, glass,
Various support materials such as plastic plates such as acrylic resin, plastic films such as polyester, paper, metal, etc. can be used, or if recording is performed by irradiating radiation from the substrate side, recording radiation of a specific wavelength can be used. Use something that allows the lines to pass through.

When forming the recording layer 2 by coating a coating solution prepared by mixing an OA compound and a croconic methine dye in a suitable volatile solvent on the substrate 1, the coating solution includes the substrate] and the coating solution. In order to improve the adhesion between the two, a binder made of natural or synthetic polymer may be added as appropriate. Furthermore, various additives may be added to improve the stability ratio and quality of the recording layer 2.

The solvent used for coating depends on the f of the binder used.
I, OA compounds and f of croconic methine dyes
! Generally, methanol,
Alcohols such as ethanol and isopropanol: Ketones such as acetone, methyl ethyl ketone, and cyclohexanone: Ketones such as N,N-dimethylformamide, N,N-dimethylacetamide Sulfoxides such as dimethyl sulfoxide: tetrahydrofuran, dioxane,
Ethers such as ethylene glycol monomethyl ether: Esters such as methyl acetate, ethyl acetate, butyl acetate: Aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichlorethylene: Hensen, toluene , xylene, monochlorobenzene, dichlorobenzene, and other aromatic hydrocarbons.

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, a beat coating method, a wire bar coating method, a blade coating method, a roller coating method,
A method such as a curtain coating method is used.

In this case, the thickness of the recording layer 2 is suitably about 500 to 2 microns, and particularly preferably from 1000 to 5000. The blending ratio of the OA compound and the croconic methine dye in the recording layer 2 is preferably about 1715 to 1071, and optimally about 171a to 5/1.

On the other hand, a typical structure of an optical recording medium used in the method of the present invention in which the recording layer 2 is formed from a monomolecular film or a monomolecular cumulative film is illustrated in FIGS. 4 and 5. In the example shown in FIG. 4, a recording layer 2 consisting of a mixed monomolecular film of the OA compound 7 and the croconic methine dye 6 is formed on a substrate 1, and in FIG. It was established.

A recording layer 2 made of such a monomolecular film or a monomolecular cumulative film is formed on the substrate 1 (for example, 1.Lar+
The Langmuir-Prodgett method (hereinafter abbreviated as LB method) developed by Gmuir et al. is used.

In the LB method, when a molecule with a structure that has a parent wood group and a hydrophobic group in the molecule maintains a suitable balance between the two (balance of amphiphilicity), this molecule will hold the 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 layering of monomolecular molecules facing downward. A monolayer on the water surface has the characteristics of a two-dimensional system. When the molecules are sparsely dispersed, the two-dimensional ideal gas equation, nA=kT, holds between the area A per molecule and the surface pressure hole, resulting in a "gas film". Here, k is Boltzmann's constant and k is the absolute temperature. If 8 is made small enough, the intermolecular interaction becomes strong and a two-dimensional solid "condensed film (or solid film)" is formed.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 both a hydrophilic site and a hydrophobic group in a hydrophobic portion. 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.

Using this method, a mixed monomolecular preshock or mixed monomolecular cumulative film of an OA compound and a croconic methine dye constituting the recording layer of the present invention is produced, for example, as follows.

First, an OA compound and a croconic methine dye are dissolved in a solvent such as chloroform, and this is developed in an aqueous phase to form a developed layer in which these compounds are developed into a film.Next, this developed layer is To prevent the compound from spreading freely on the phase and spreading too much, a partition plate (or float) is provided to limit the area of the developed layer, thereby controlling the state of aggregation of these compounds, and obtaining a surface pressure port proportional to the state of aggregation. By moving this partition plate, the developed area can be reduced to control the aggregation state of the film material, gradually increasing the surface pressure, and setting the surface pressure suitable for producing a cumulative film. A mixed monomolecular film of OA compound and croconic methine dye is transferred onto the substrate by gently lifting and lowering the clean substrate vertically while maintaining the temperature.The mixed monomolecular film is produced in this way. A mixed monomolecular layer cumulative film having a desired degree of accumulation is formed by repeating the above-mentioned operations.

In order to transfer the monomolecular film onto the substrate, in addition to the above-mentioned vertical dipping method, methods such as horizontal adhesion method and rotating cylinder method can be employed. 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 layer is formed on the substrate or a monomolecular layer with the parent group of the DA compound facing toward 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 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 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 OA 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 parent wood groups in all layers face the substrate side is called a type 7 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 one method, 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 1 Day Interface 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 OA compound and the croconic methine dye. A medium is obtained.

In this case, the film thickness of the recording layer (cumulative number of monomolecular films) is 5 to
400 is suitable, and a range of 20 to 170 is particularly preferred. The mixing ratio of the OA compound and the croconic methine dye in the recording layer is the same as in the case of the coating method described above.

Note that various protective layers may be provided on the recording layer configured in this way, if necessary.

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, DA compounds (excluding polymers) (by applying this light, the absorption wavelength of the recording layer changes and the apparent color changes. In other words, 〇 crystal compounds (excluding polymers) Initially, it is almost colorless and transparent, but upon irradiation with ultraviolet rays, it polymerizes and transforms into a polydiacetylene derivative compound.This polymerization occurs only by irradiation with ultraviolet rays, and cannot be performed without the application of other physical energy such as heat. As a result of this polymerization, it has a maximum absorption wavelength in the range of 620 to 660 nm, and the color changes from blue to dark.The change in hue due to this polymerization is an irreversible change,
Once the recording layer changes to blue or dark color, it does not return to a colorless transparent film.

Furthermore, when a semiconductor laser is irradiated onto the recording layer containing the blue or dark colored polydiacetylene derivative compound and croconic methine dye, the croconic methine dye absorbs the light and generates heat, which causes the recording layer to become heated. The area irradiated with light melts. The energy required for melting at this time is significantly smaller than when the recording layer is formed using croconic methine dye alone.

The optical recording method of the present invention performs recording by utilizing the characteristics obtained by the combination of such an OA compound and a 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, when using an optical recording medium having an optical recording layer that contains an OA compound (excluding polymers) and a chlorotic methine dye, first, The entire recording layer is irradiated with ultraviolet light.

By irradiating this ultraviolet ray, as mentioned above, the O in the recording layer is
Compound A (excluding the polymer) is polymerized and changed into a polydiacetylene derivative compound, and the recording layer changes color into a blue to dark film. (Of course, this operation is not required for those having a recording layer that uses a polydiacetylene derivative compound directly as an OA compound.) On the other hand, the recorded information is converted into an optical signal (converted by a semiconductor laser) via a control circuit. .This optical signal passes through an optical system,
For example, as shown in FIG. 2, an image is formed on a predetermined position of a disc-shaped optical recording medium placed on an optical recording medium snow mounting means and rotating synchronously. The imaged lightning is the recording layer 2 of the optical recording medium.

The croconic methidi dye present at the imaging point (site) 3 absorbs this laser beam 4 and generates heat. The heat generated by this croconic methine dye melts the recording layer 2 at the imaging point 3, forming pits with a 4° recess 5 as shown in FIG. As described above, the recording layer 2 of the medium is composed of a combination of a croconic methine dye and a polydiacetylene derivative compound, so the presence of the polydiacetylene derivative compound causes the above-mentioned effect on the croconic methine dye 1.・In other words, compared to pit formation in a recording layer composed of only croconic methidi dye, it is highly sensitive to semiconductor lasers, and it is possible to use semiconductor lasers with the same output. In this case, the exposure time using the laser beam can be reduced.

In this way, optical recording is performed by forming pits in the recording layer according to input information.

In the above example, the optical recording medium is a disc-shaped disk (
Although an optical disk (optical disk) was used, of course, optical tape, optical card, etc. can also be used depending on the type of substrate supporting the recording layer containing the OA compound and the croconic methine dye.

〔Effect of the invention〕

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

(1) Since the recording layer contains a combination of a croconic methine dye and a polydiacetylene derivative compound, high sensitivity and high speed recording can be performed even using a small and lightweight semiconductor laser.

(2) Since the recording layer is formed homogeneously and with good surface properties, it is possible to perform high-quality optical recording with excellent stability. Furthermore, when the recording layer is formed of a mixed monomolecular film of an OA compound and a croconic methine dye or a cumulative film thereof, the recording layer has a higher density and a higher degree of order, and therefore has a higher density. High-density and homogeneous recording is possible.

(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-C=C-CoH+6-
1 part by weight of fine crystalline powder of a diacetylene derivative compound represented by C0OH and 15 parts by weight of the croconic methine dye represented by dye A25 are added to 30 parts by weight of methylene chloride and thoroughly stirred to prepare a coating solution. did.

Next, a glass disk substrate (thickness 1.5 mm, diameter 2
00 mm) on a spinner coating machine, and apply a small amount of the coating liquid to the center of the disk substrate. 'After dropping, apply by rotating a spinner at a predetermined rotation speed for a predetermined time, dry at room temperature, and the thickness of the coating film after drying on the substrate is 500 and 100.
Optical recording media for 0 and 2000 people were created, respectively.

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

Next, each optical recording medium having this blue film recording layer was irradiated with a laser beam for 40 hours per bit.
Optical recording was performed under the following recording conditions, except for various changes between 0 ns and 5 us.

Semiconductor laser wavelength: 830 nm Laser beam diameter = 1 - Laser output 3 mW After completing the recording under conditions of 3 mW or more, observe the recording results on each optical recording medium (with a microscope), and We investigated the laser beam irradiation time required to form pits consisting of clear concave parts.
Shown in the table.

Next, the optical recording media recorded with an irradiation time of 900 ns/1 bit were comprehensively evaluated in terms of resolution and contrast ratio between pit and non-pit areas. Items that could not be recorded or were defective were marked as ×.The results are shown in Table 1.

Example 2 The amount of diacetylene derivative compound was 1 part by weight, the amount of croconic methine dye was 10 parts by weight, and the amount of methylene chloride was 2 parts by weight.
An optical recording medium was prepared in the same manner as in Example, using a mixed solution containing 0 parts by weight as a coating liquid.

In this way, first add two
After uniformly and sufficiently irradiating the recording layer with 54 nm ultraviolet rays to make the recording layer a blue film, optical recording was performed in the same manner as in Example],
This was evaluated. Table 1 shows the evaluation of the recorded results.

Example 3 The amount of diacetylene derivative compound was 1 part by weight, the amount of croconic methine dye was 5 parts by weight, and the amount of methylene chloride was 1 part by weight. An optical recording medium was prepared in the same manner as in Example 1 using a mixed solution containing 12 parts by weight of : as a coating liquid.

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 and coating the recording layer with a blue film, optical recording was performed in the same manner as in Example 1.
This was evaluated. Table 1 shows the evaluation of the recorded results.

Example 4 A mixed solution containing 1 part by weight of the diacetylene derivative compound, 1 part by weight of the croconic methine dye, and 4 parts by weight of methylene chloride was used as the coating liquid, and the same procedure as in Example 1 was carried out. An optical recording medium was prepared by the method.

Each of the optical recording media obtained in this way was first uniformly and sufficiently irradiated with 254 nm ultraviolet rays to make the recording layer a blue film, and then optical recording was performed in the same manner as in Example 1. The evaluation of the recorded results is shown in Table 1.

Example 5 A mixed solution containing 5 parts by weight of jl of a diacetylene derivative compound, 1i-i + parts by weight of croconic methine dye, and 12 parts by weight of methylene chloride was used as a coating liquid,
An optical recording medium was produced in the same manner as in Example 1.

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 evaluated. Table 1 shows the evaluation of the recording results. show.

Example 6 A mixed solution containing 10 parts by weight of the diacetylene derivative compound, 1+ parts by weight of the croconic methine dye, and 20 parts by weight of methylene chloride was used as the coating solution, and the same method as in Example 1 was carried out. An optical recording medium was created.

Each of the optical recording media obtained in this way (first, two
After uniformly and sufficiently irradiating with 54 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. Table 1 shows the evaluation of the recorded results.

Example 7 The amount of diacetylene derivative compound was 15 parts by weight, the amount of croconic methine dye was 1 part by weight, and the amount of methylene chloride was 3 parts by weight.
An optical recording medium was prepared in the same manner as in Example 1 using a mixed solution containing 0 parts by weight as a coating liquid.

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. Table 1 shows the evaluation of the recorded results.

Comparative Example 1 An optical recording medium was prepared in the same manner as in Example 1, using a solution of 1 part by weight of a diacetylene derivative compound added to 2 parts by weight of methylene chloride as a coating liquid, without using a croconic methine dye. did.

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 and coating the recording layer with a blue film, optical recording was performed in the same manner as in Example 1.
This was evaluated. Table 1 shows the evaluation of the recorded results.

Comparative Example 2 An optical recording medium was prepared in the same manner as in Example 1, using a solution of 1 part by weight of croconic methine dye dissolved in 2 parts by weight of methylene chloride as a coating liquid, without using a diacetylene derivative compound. did.

Each of the optical recording media thus obtained was directly irradiated with a semiconductor laser beam under the same conditions as in Example 1 according to the input information, without performing ultraviolet irradiation, to perform recording. Table 1 shows the evaluation of the recording results.

Table 1 Example 8 A mixture in which the amount of diacetylene derivative compound was 1 part by weight, the amount of croconic methine dye was 1 part by weight, the amount of methylene chloride was 4 parts by weight, and 2 parts by weight of nitrocellulose was added as a binder. Using the solution as a coating liquid, an optical recording medium with a recording layer thickness of 3000 was prepared in the same manner as in Example 1.

After this optical recording medium was uniformly and sufficiently irradiated with 254 nm ultraviolet rays to turn the recording layer into a blue film, recording of input information was performed under the following recording conditions.
Laser beam irradiation time per 1 bit is 400n
Various changes were made between s and 5 us.

Semiconductor laser wavelength: 840 nm Laser beam diameter: 1 μm Laser output power 3 mW Comparative Example 3 Without using a diacetylene derivative compound, 2 parts by weight of croconic methine dye and 2 parts by weight of nitrocellulose were dissolved in 4 parts by weight of methylene chloride. Solution 5] was used as a coating solution, and an optical recording medium with a recording layer thickness of 3000 was prepared in the same manner as in Example 1.

This optical recording medium was directly irradiated with a semiconductor laser beam according to the input information under the same conditions as in Example 8, without performing ultraviolet irradiation, to perform recording.

Regarding the optical recording medium of Example 8, as a result of microscopic observation, it was found that if the irradiation time was 1000 ns/1 bit or more (this indicates whether good recording could be performed), the optical recording medium of Comparative Example 3 was To clearly form two pits, 1
An irradiation time of 800 ns/1 bit or more was required.

Example 9 General formula Cl2H7-5C3C-C3C-C3HL6 G
Instead of the diacetylene derivative compound represented by OON,
General formula C8H17c=c-c=c-c? H4-coah
An optical recording medium was prepared in the same manner as in Example 3 except that the compound shown above was used.

The optical recording medium thus obtained was first uniformly and sufficiently irradiated with 254 nm ultraviolet rays to make the recording layer a blue film, and then recording was carried out under the same recording conditions as in Example 1, with no clear pits. The light irradiation time and resolution required for formation, and the cossilast ratio of pits and non-pits were evaluated. The results are shown in Table 2.

Examples 10 to 13 The croconic methine dye represented by Dye Description 25 (in place of the above-mentioned dye report, except that the croconic methine dye represented by 2.29.37.42 was used) Optical recording media were prepared in the same manner as in Example 9. Each of these optical recording media was first uniformly and sufficiently irradiated with 254 nm ultraviolet rays to turn the recording layer into a blue film, and then in the same manner as in Example]. Optical recording was performed and evaluated. Table 2 shows the evaluation of the recording results.

Table 2 Example 14 General formula CI2 H2s-C=C-C=C-CeH+b-
1 part by weight of the diacetylene derivative compound represented by Golo and 15 parts by weight of the croconic methine dye represented by dye 6 above were mixed in chloroform with 3XIO-3 mol/1.
The solution was developed on an aqueous phase having a pH of 6.5 and a cadmium chloride concentration of 1X10-3 mol/1.

After removing the solvent chloroform, while keeping the surface pressure constant, the glass substrate whose surface had been thoroughly cleaned was gently moved up and down in the direction across the water surface at a vertical speed of 1.0 cm for 7 minutes to remove the OA compound. A mixed monomolecular film with a croconic methine dye was transferred onto a substrate, and an optical recording medium was created in which a mixed monomolecular film and a mixed monomolecular cumulative film of 21 layers, 41 layers, and 81 layers were formed on the substrate. .

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. Table 3 shows the evaluation of the recorded results.

Example 15 Example 14 except that the diacetylene derivative compound was 1 part by weight per 10 parts by weight of the croconic methine dye.
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 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. Table 3 shows the evaluation of the recorded results.

Example 16 An optical recording medium was prepared in the same manner as in Example 14, except that 1 part by weight of the diacetylene derivative compound was used for 5 parts by weight of the croconic methine dye.

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. Table 3 shows the evaluation of the recorded results.

Example 17 An optical recording medium was prepared in the same manner as in Example 14, except that 1 part by weight of the diacetylene derivative compound was used for 1 part by weight of the croconic methine dye.

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. Table 3 shows the evaluation of the recorded results.

Comparative Example 4 An optical recording medium was prepared in the same manner as in Example 14, except that no croconic methine dye was used (only a diacetylene derivative compound was used).

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], and this was evaluated. The evaluation of the recording results is shown in Table 3.

Table 3 Example 18 General formula CI2 H2s-C=C-C:C-CBH+6-
Instead of the diacetylene derivative compound represented by GO Kano,
General formula CoH+7-C=c-C=C-C2Hn-COO
Example 16 except that the compound indicated by H 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 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], and this was evaluated. Table 4 shows the evaluation of the recorded results.

Examples 19 to 22 The same procedure as in Example 18 except that the croconic methine dye represented by dye description 14.24.35.39 was used instead of the croconic methine dye represented by /FL6. An optical recording medium was prepared by the method. Each of these optical recording media was first uniformly and sufficiently irradiated with 254 nm ultraviolet rays to form a blue film in the recording layer, and then optical recording was performed in the same manner as in Example 1 and evaluated. The evaluation of the recording results is shown in Table 4.

6゜ Table 4

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view illustrating one aspect of the structure of an optical recording medium used in the method of the present invention, FIGS. 2 and 3 are schematic cross-sectional views of the optical recording medium illustrating the optical recording process of the present invention, Figure 4 shows a method of the present invention in which the recording layer is formed of a monomolecular film (a schematic cross-sectional view illustrating one aspect of the structure of the optical recording medium to be used), and Figure 5 shows a method in which the recording layer is formed of a monomolecular film. 1 is a schematic cross-sectional view illustrating one aspect of the structure of the formed optical recording medium. 1: Substrate 2: Recording layer 3: Light irradiation (recording) region 4: Laser beam 5: Pit 6: Croconic methine dye 7: Diacetylene derivative compound

Claims (1)

[Claims] 1) A step of irradiating an optical recording medium having a recording layer containing a polydiacetylene derivative compound and a croconic methine dye with light according to recorded information to form pits consisting of concave portions in the recording layer. An optical recording method characterized by comprising: