JPS6351185A - Optical recording method - Google Patents

Abstract

PURPOSE:To enable a high-speed recording with a small, light-weight, low-output semiconductor laser, by a method wherein a light is irradiated according to recording information to an optical recording medium provided with a recording layer containing a polydiacetylene derivative compound and a squarylium dye to form pits made of recessed portions on the recording layer. CONSTITUTION:A recording layer 2 containing a diacetylene derivative compound and a squarylium dye is formed on a substrate 1. An ultraviolet light is irradiated all over the recording layer, whereby the diacetylene derivative compound is polymerized and changed to a polydiacetylene derivative compound. On the other hand, recording information through a control circuit is converted to optical signals by a semiconductor laser to be imaged in position on the recording layer 2 of a disk-form optical recording medium synchronously rotating. Since the sqnarylium dye existing in imaging points 3 absorbs a laser beam 4 for heating, the recording layer 2 corresponding to the imaging points 3 is melted to have pits made of recessed 5. In this manner, a high-sensitivity parts and high-recording can be conducted.

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 high-density, high-sensitivity, high-speed bit 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 can record and store a large amount of documents, documents, etc. on a single disc, so they can be used to organize documents, etc. in the office.
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, 1-sized dots) 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. 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. In the case of pit recording, the output of the photodetector is reduced in areas where pits are not formed, whereas in areas where bits are formed, the laser beam is sufficiently reflected by the reflective surface of the underlying layer and the output of the photodetector is reduced. output becomes larger.

Conventionally, the recording layer of such optical disks has been made of various types, such as fully refractive thin films such as aluminum evaporated films, bismuth thin films, tellurium oxide thin films, and inorganic materials such as chalcogenide amorphous glasses11. Although various methods have been considered, products using organic materials are attracting attention due to their cost and ease of manufacture.

As organic materials used for optical recording media, Japanese Patent Application Laid-Open No. 58-1
8] No. 052 and Japanese Unexamined Patent Publication No. 59-60443 disclose square aryllium dyes, and since the organic film containing the stiff dye absorbs radiation in the semiconductor laser radiation wavelength region and generates heat, the laser energy is It is known that it is possible to perform so-called heat mode recording in which pits are formed.

[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 than a recording method that forms dots by discoloration, and the recording speed is 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 not to damage the surface of the recording medium even after recording. At the same time, it has been difficult to perform high-density, high-sensitivity recording.

For example, when forming the recording layer of an optical recording medium from the above-mentioned square lyllium dye, the square lyllium dye absorbs a semiconductor laser beam (infrared rays) and generates heat, and as a result of this heat generation, it self-melts, so this characteristic can be utilized. It is possible to form pits on an optical recording medium. However, it requires a large amount of energy to form pits, has low sensitivity, and requires a relatively long constant exposure (light irradiation) time. 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 an optical recording medium by forming a recording layer of an optical recording medium by combining a square aryllium dye and a diacetylene conductor compound. The present invention was completed by discovering that the pit formation rate under light irradiation is significantly accelerated even when a low-power semiconductor laser is used.

An object of the present invention is to provide an optical recording method that allows 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.

[Failure to solve the problem]

That is, in the optical recording method of the present invention, an optical recording medium having a recording layer containing a polydiacetylene derivative compound and a square aryllium dye is irradiated with light according to recorded information to form pits consisting of recesses in the recording layer. It is characterized by having a step of forming.

The diacetylene derivative compound (hereinafter abbreviated as D-formula compound) contained in the optical recording medium used in the method of the present invention has the following general formula R-CE C-CE (: -R' (in the formula, R and R' are a polar group: alkyl J, which may be substituted with a polar group, (a saturated aliphatic hydrogen group such as a cyclohexyl group: a vinyl group, which may be substituted with a polar group, ) or an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, or an alkylphenyl group, which may be substituted with a polar group; examples of the polar group here include a carboxyl group or Its metal or amine salt, sulfonic acid group or its metal or amine salt, sulfamide group, amide 2
Examples include H, amino group, imino group, hydroxy group, oxyamino group, diazonium group, guanidine group, hydrazine group, phosphoric acid group, silicate group, aluminic acid group, nitrile group, thioalcohol group, nitro group and halogen atom. It will be done. ) and their polymers.

Furthermore, as described later, the recording layer may be a monomolecular film or a monomolecular film.
When forming a JO+ or laminated film, the D^ compound is a compound capable of a 1°4-addition polymerization reaction between CEC-CEC-C functional groups in adjacent molecules, typically represented by the following general formula %. % In the formula, x includes a compound represented by the tree-philicity J, (where m and n represent integers) that form a hydrophilic site.

In this case, the wood-philicity j, l; It will be done. The alkyl group represented by 11 (C: 112) and - forming a hydrophobic site has 1 to 30 carbon atoms.
Long chain alkyl J, H is preferred. Further, n+m is preferably an integer of 1 to 30.

- On the other hand, the squarelylium dye used in the present invention is a compound (with an inner salt) having the following basic structure: (including 800)
It is a compound that has an absorption peak at ~900 nm and generates heat when exposed to infrared light at this wavelength. As the square aryllium dye, dyes represented by the following general formulas [I] to [IV] are typically exemplified.

n'bu [I] Hide-1 Suzuki [+1 Koshi 0θM (+) , methyl group, ethyl group, n-propyl (
, 1so-propyl group, n-butyl group, 5ec-butyl group, 1so-butyl group, shi-butyl group, n-amyl group,
t-amyl"1 (, rhohexyl group, n-octyl group,
octyl group, etc.), substituted alkyl groups (e.g. 2- and droxyethyl groups, 3-hydroxypropyl groups, 4-hydroxybutyl groups, 2-acetoxyethyl groups, carboxymethyl groups, 2-carboxyethyl groups, 3-carboxyethyl groups, Pheasant propyl group, 2-sulfoethyl group, 3-sulfopropyl group, 4-sulfobutyl group, 3-sulfatepropyl,
+, 1. ．． 4-sulfatebutyl group, N-(methylsulfonyl)-carbamylmethyl group, 3-(acetylsulfamyl)propyl group, 4-(acetylsulfamyl)butyl group, etc.), 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.), 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-Simethoxyhenzothiazole, 5.6-Sioxymethylenebenzothiazole, 5-Hydroxybenzothiazole, 6-Hydroxybenzothiazole, 4,5,6
．． 7-titrahydrobenzothiazole, etc.), naphthothiazole series nuclei (e.g. naphtho[2,1-d]deazole, naphtho[1,2-d]thiazole, 5-methoxynaphtho[1,2-d]thiazole, 5 -ethoxynaphtho[1,2-d]deazole, 8-methoxynaphtho[2
,1-d]thiazole, 7-methoxynaphtho[2,1-
d]thiazole, etc.), thionaphthene[7,6-d]thiazole series nuclei, (e.g. 7-Medquinthionaphthene[7,6-d]thiazole), oxazole series nuclei (
For example, 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-dimethylbenzoxazole, 5-methoxybenzoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole , 6-hydroxybenzoxazole, etc.), naphthoxazole 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.), naphthoselenazole series nuclei (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-human oxymethylthiazoline, 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), l-isoquinoline series nuclei (e.g. isoquinoline, 3,4-dihydroisoquinoline), 3-isoquinoline series nuclei (e.g. isoquinoline), 3,3-dialkylindolenine series nuclei ( For example, 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. l-ethyl-5,6-dichlorobenzimidazole,
1- and droxyethyl-5,6-dichlorobenzimidazole, l-ethyl-5-chlorobenzimidazole,
l-ethyl-5,6-dibromobenzimidazole, 1
-ethyl-5-phenylbenzimidazole, 1-ethyl-5-fluorobenzimidazole, 1-ethyl-5
-cyanobenzimidazole, 1-(β-acetoxyethyl)-5-cyanobenzimidazole, I-ethyl-
5-chloro-6-cyanobenzimidazole, l-ethyl-5-fluoro-6-cyanobenzimidazole, l
-ethyl-5-acetylbenzimidazole, 1-ethyl-5-carboxybenzimidazole, 1-ethyl-
5-Ethoxycarbonylbenzimidazole, l-ethyl-5-sulfamylbenzimidazole, 1-ethyl-5-N-ethylsulfamylbenzimidazole, 1
-ethyl-5,6-difluorobenzimidazole, l
-ethyl-5,6-dichlorobenzimidazole, 1-
Ethyl-5-ethylsulfonylbenzimidazole, 1
-ethyl-5-methylsulfonylbenzimidazole,
l-ethyl-5-trifluoromethylbenzimidazole, l-ethyl-5-trifluoromethylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylsulfinylbenzimidazole, etc.). represent X is a chloride ion,
Represents an anion such as bromide ion, iodide ion, perchlorate ion, benzenesulfonate ion, p-toluenesulfonate ion, methyl sulfate ion, ethyl sulfate ion, propyl sulfate ion, etc., and X is R1 and/or θ e or R2 itself is an anionic group, for example -503, -0SO
3.■ 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 the general formula (I[+) (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, R'' and R6
can be combined with R to form a benzene ring, and R
5 and R6 can be combined with R7 and R8 to form a benzene ring.

Next, typical examples of the square aryllium dye used in the present invention are listed below, but for convenience, general formula [I] or [I
II] in the form of a betaine structure. However, in the preparation of these dyes, mixtures of dyes in betaine or salt form are obtained and are therefore used as mixtures.

Representative example of general formula [11, [+11] (2).

Misfortune (3).

four (4).

(7).

(8).

鑵 (9).

(10).

II (II) O (+3) O (14)
.

(15)　　　　　　　　　.

Place (16)　　　　　　　　　.

Shit　　　　　　　　 (17)　　　　　　　　　　.

(18).

(19)　　　　　　　　　.

■ (20)　　　　　　　　　.

(21).

CHC)1 CH2CH2 CH3 CH, C・H5ro” C, H.

(2B) 0e General formula [m], '[Representative example of IVl The square lyllium dyes 4 of the above (1) to (42) are 1
A species or a combination of two or more species can be used.

A typical configuration of the optical recording medium used in the present invention is shown in FIG. In this example, a recording layer 2 containing the above-described compound and a square aryllium dye is provided on a substrate 1.

The recording layer 2 of the optical recording medium used in the present invention contains the foregoing compound and the square aryllium dye,
Typically, a coating solution is prepared by mixing a fine crystalline powder of an OA compound and a square aryllium dye in a suitable volatile solvent, and this coating solution is applied onto a substrate, or a DA compound and a square are coated on a substrate. It can be obtained by a method such as forming a mixed monomolecular film with a lyllium dye or a mixed monomolecular cumulative film.

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

When forming the recording layer 2 by coating the substrate 1 with a coating solution prepared by mixing a DA compound and a squarerium dye in a suitable volatile solvent, the coating solution includes the following:
In order to improve the tightness between the substrate 1 and the substrate 1, a binder made of natural or synthetic polymer may be added as appropriate. Furthermore, various additives may be added to improve the stability and quality of the recording layer 2.

The solvent used for coating is appropriately selected depending on the type of binder used and the type of DA compound and squarellium dye, but generally alcohols such as methanol, ethanol, isopropanol; acetone, methyl ethyl ketone, cyclohexanone, etc. ketones, I
Ketones such as 'r, N-dimethylformamide, If, N-dimethylacetamide; Sulfoxides such as dimethyl sulfoxide; Ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether;
Esters such as methyl acetate, ethyl acetate, butyl acetate;
Dichloromethane, chloroform, carbon tetrachloride, methylene chloride, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene,
Aliphatic halogenated hydrocarbons such as bromobenzene, 1,2-dichlorobenzene, dichloroethylene, carbon tetrachloride, and trichloroethylene; Aromatic hydrocarbons such as benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, etc. etc.

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 bead 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 thick, particularly preferably 1000 to 5000 thick. The blending ratio of the DA compound and the square aryllium dye in the recording layer 2 is preferably about 1/15 to 1071, and optimally 1710 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 above-mentioned compound 7 and square lylium dye 6 is formed on a substrate 1, and in FIG. 5, a cumulative monomolecular film of these mixtures is formed. It has been established.

In order to form the recording layer 2 made of such a monomolecular film or a monomolecular cumulative film on the substrate 1, for example, 1. Langm
The Langmuir-Prodgett method (hereinafter abbreviated as LB method) developed by Uir 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 two-dimensional ideal gas equation, nA=kT, holds between the surface per molecule JHIA and the surface pressure n, resulting in a "gas film." Here, k is Boltzmann's constant and T is absolute temperature. If A is made sufficiently small, the intermolecular interaction becomes strong, resulting in a two-dimensional solid "condensed film (or solid@)". 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 site. 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 film or a mixed monomolecular cumulative film of a DA compound and square lylium dye constituting the recording layer of the present invention is produced, for example, as follows. First, a DA compound and square lium dyed stone 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 into 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 monsters. Obtain a surface pressure n proportional to the state. By moving this partition plate, the developed area can be reduced to control the state of aggregation of the film material, and the surface pressure can be gradually increased to set the surface pressure (2) suitable for producing a cumulative film. By gently moving the clean substrate vertically up and down while maintaining this surface pressure, a mixed monomolecular film of the DA compound and the square aryllium dye is transferred onto the substrate. A mixed monomolecular layer film is produced in this manner, and a mixed monomolecular layer cumulative film having a desired degree of accumulation is formed by repeating the above-mentioned operations.

In addition to the above-mentioned vertical dipping method, methods such as a horizontal deposition method and a rotating cylinder method can be used to transfer the monomolecular film onto a substrate. The horizontal deposition method is a method in which the substrate is brought into horizontal contact with the water surface and transferred, and the rotating cylinder method is a method in which a cylindrical substrate is rotated on the water surface to transfer a 1-0 molecular 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 monomolecular layer with the hydrophilic groups of the DA compound facing the substrate is formed on the -th layer. . As the substrate is moved up and down, one layer of mixed monomolecular film is deposited with each step. Since the direction of the film-forming molecules is reversed between the pulling process and the dipping process, according to this method, a Y-shaped film is formed between each layer in which parent wood groups and parent wood groups, and hydrophobic groups face each other.

On the other hand, the horizontal deposition method is a method in which the substrate is brought into contact with the water surface horizontally and transferred, and a monomolecular layer of the D-type compound with the hydrophobic group facing the substrate is formed on the substrate. In this method, even when accumulated, the orientation of the molecules of the eye compound does not change, and an X-shaped 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 above-mentioned hydrophilic groups, hydrophobic groups, and () toward the substrate is in principle, 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 chirality, so variations in light absorption depending on location are extremely small. Therefore, by configuring the recording layer with such a film, a high-density, high-resolution recording medium capable of optical recording and thermal recording can be created, depending on the function obtained by the combination of the DA compound and the square aryllium dye. is obtained.

The film thickness of the recording layer in this case (cumulative number of monomolecular films) is 5
-400 is suitable, with a range of 20-170 being particularly preferred. The mixing ratio of the DA compound and the square aryllium 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, by applying light to the D-type compound (excluding the polymer), the absorption wavelength of the recording layer changes and the apparent color changes. That is, the D formula compound (excluding the polymer) is initially almost colorless and transparent, or upon irradiation with ultraviolet rays, it polymerizes and changes into a polydiacetylene derivative compound. This polymerization occurs only by irradiation with ultraviolet light and not by the application of other physical energy such as heat. As a result of this polymerization, it has a maximum absorption wavelength of 620 to 66 Dnm, and its color changes from blue to dark.

This change in hue due to polymerization is an irreversible change, and the recording layer that has changed from blue to dark does not return to a colorless transparent film.

Furthermore, when a semiconductor laser is irradiated onto the recording layer containing the polydiacetylene derivative compound and the square aryllium dye, which has changed to a blue or dark color, the square aryllium dye absorbs the light and generates heat, which causes the recording layer to be irradiated with the light. The part melts. The energy required for melting at this time is significantly smaller than when the recording layer is formed using square aryllium dye alone.

The optical recording method of the present invention performs recording by utilizing the characteristics obtained by the combination of such a round compound and square lylium 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 85 Qnm.

When carrying out the optical recording method of the present invention, when using an optical recording medium having an optical recording layer containing a DA compound (excluding a polymer) and a square aryllium dye, first, the recording layer is Irradiates the entire area with ultraviolet light. By irradiating this ultraviolet ray, the DA in the recording layer is
The compound (excluding the polymer) is polymerized and converted into a polydiacetylene derivative compound, and the recording layer changes color into a blue to dark-colored film. (Of course, this operation is not required for those that have a recording layer that uses a polydiacetylene derivative compound directly as a DA compound6) 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, is placed on, for example, an optical recording medium mounting means, and is imaged at a predetermined position on a synchronously rotating disc-shaped optical recording medium, as shown in FIG. The imaging position is the recording layer 2 of the optical recording medium.

The square lyllium dye present at the imaging point (site) 3 absorbs this laser beam 4 and generates heat.

The heat generated by the square aryllium dye melts the recording layer 2 at the imaging point 3, forming a bit consisting of a concave portion 5 as shown in FIG. In this case, since the recording layer 2 of the recording medium used in the present invention is composed of a combination of a squareylium dye and a polydiacetylene derivative compound as described above, in other words, the presence of a polydiacetylene derivative compound causes a squareylium The above-mentioned bit formation by the dye is greatly promoted. In other words, compared to pit formation in a recording layer composed of square aryllium dye alone, it is highly sensitive to semiconductor lasers, and when using a semiconductor laser with the same output, the exposure time with the laser beam is shorter. I'll try it.

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

In the above example, the optical recording medium is a disc-shaped disk (
Although an optical disc (optical disc) was used, of course optical tapes, optical carts, etc. can also be used depending on the type of substrate supporting the recording layer containing the DA compound and square lylium 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 squareylium dye and polydiacetylene derivative compound,
High-sensitivity, high-speed recording can be performed using a small and lightweight semiconductor laser.

(2) Since the recording layer is formed uniformly and with good surface properties, it is possible to perform optical recording with excellent stability and high quality. Furthermore, when the recording layer is formed of a mixed monomolecular film of a DA compound and a square aryllium dye or a cumulative film thereof, the recording layer has a higher density and a higher degree of order, and therefore has a higher It is possible to record with uniform density.

(3) Optical recording using an inexpensive recording medium with 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 c, 2H2, -c=c-c3C-C3H16Go
Diacetylene derivative compound crystal fine powder represented by leaves 1
Parts by weight and 15 parts by weight of the squareylium dye represented by Dye Makoto 37 in No. 11'1 were added to 2OTii parts of methicine chloride and thoroughly stirred to prepare a coating liquid.

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 coating liquid was dropped onto the center of the disc substrate, and then the spinner was applied at a predetermined rotation speed for a predetermined period of time. The thickness of the coating film after drying on the substrate is 500 mm and 1000 mm.
Optical recording media for 2000 people 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-colored recording layer was irradiated with a laser beam for 400 hours per pit.
Optical recording was performed under the following recording conditions, except for various changes between ns and 5 μs.

Semiconductor laser wavelength: 830 nm Laser beam diameter: IP Laser output 8 [OW] After completing recording under the above conditions, the recording results on each optical recording medium were observed using a microscope, and a clear depression was observed in the laser beam irradiation area. The laser beam irradiation time required to form a bit consisting of was investigated. The results are shown in Table 1.

Next, we comprehensively evaluated the resolution and the contrast ratio between bit and non-bit areas of the optical recording media recorded with an irradiation time of 1000 ns/1 bit, and evaluated the particularly good one as ◎, and the good one as O1 recording. Items that could not be completed 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 square lium dye was 10 parts by weight, and the amount of methylene chloride was 20 parts by weight.
Example 1 A mixed solution expressed as parts by weight was used as a coating liquid.
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 1 shows the evaluation of the recorded results.

Example 7ih Example 3 A mixed solution containing 1 part by weight of the diacetylene derivative compound, 5 parts by weight of the squareylium dye, and 12 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 given 25
After uniformly and sufficiently irradiating the recording layer with 4r++n 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.

Example 4 The same method as in Example 1 was carried out using a mixed solution containing 1 part by weight of the diacetylene derivative compound, 1 part by weight of the squareylium dye, and 4 parts by weight of methylene chloride as the coating liquid. An optical recording medium was created.

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.

Example 5 The same method as in Example 1 was carried out using a mixed solution containing 5 parts by weight of the diacetylene derivative compound, 1 part by weight of the squareylium dye, and 12 parts by weight of methylene chloride as the coating liquid. An optical recording medium was created.

Each of the optical recording media obtained in this way was first given 25
After uniformly and sufficiently irradiating the recording layer with 4++ m 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 6 The amount of diacetylene derivative compound was 10 parts by weight, the amount of squarelylium dye was 1 part by weight, and the amount of methylene chloride was 20 parts by weight.
Example 1 The mixed solution made into parts by weight was used as a coating solution.
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 1 shows the evaluation of the recorded results.

Example 7 The amount of diacetylene derivative compound was 15 parts by weight, the amount of square lium dye was 1 part by weight, and the amount of methylene chloride was 30 parts by weight.
Example 1 A mixed solution expressed as parts by weight was used as a coating liquid.
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 1 shows the evaluation of the recorded results.

Comparative Example 1 An optical recording medium was produced 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 squareylium 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 1 shows the evaluation of the recorded results.

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

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 mixed solution was prepared in which the amount of diacetylene derivative compound was 1 part by weight, the amount of square lium dye was 1 part by weight, the amount of methylene chloride was 4 parts by weight, and 2rfLm parts of nitrocellulose was added as a binder. Using this as a coating liquid, an optical recording medium with a recording layer thickness of 3000 mm was prepared in the same manner as in Example 1.

This optical recording medium was uniformly and sufficiently irradiated with 254 nm ultraviolet rays to make the recording layer a blue film, and then recording was performed under the following recording conditions according to manual information. Note that the laser beam irradiation time per bit is 400 ns to 5
Various changes were made between μS.

Semiconductor laser wavelength: 840 nm Laser beam diameter = 1 μs Laser output 8 mW Comparative Example 3 A solution in which 2 parts by weight of square aryllium dye and 2 parts by weight of nitrocellulose were dissolved in 4 parts by weight of methylene chloride without using a diacetylene derivative compound. was used as a coating liquid, and the thickness of the recording layer was 3000 mm by the same method as in Example 1.
Created a human optical recording medium.

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, good recording was possible when the irradiation time was 900 ns/1 bit or more, but for the optical recording medium of Comparative Example 3, +80 to clearly form two bits
An irradiation time of 0 ns/1 bit or more was required.

Example 9 General formula (:, 2H2, c= c-c= c-c8H, 6
Instead of the diacetylene derivative compound represented by -C00I+, general formula c8H, -c=c-c3C-C:2H4-
An optical recording medium was prepared in the same manner as in Example 3 except that the compound represented by 00014 was used.

The optical recording medium thus obtained was first uniformly and sufficiently irradiated with 254 nm ultraviolet rays to turn the recording layer into a blue film, and then recording was carried out under the same recording conditions as in Example 1, with clear bits. The light irradiation time and resolution required for formation and the contrast ratio between pits and non-pits were evaluated.

The results are shown in Table 2.

Examples 10 to 13 Example 9 except that the square aryllium dye represented by dye A/L37 was replaced with the square aryllium dye represented by the previously mentioned dye) JEL3.14.23.40, respectively. An optical recording medium was created using a similar 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. Table 2 shows the evaluation of the recorded results.

Table 2 Performance example 14 General formula C, 2H2,, -CmiC-CmiC-C3)(,6
-(: Diacetylene derivative compound 1 represented by 00H
A solution prepared by dissolving parts by weight of squareylium dye IIIffi represented by dye A2 in chloroform at a concentration of 3 x 10 = mol/l was prepared with a pH of 6.5 and a cadmium chloride concentration of 1 x 10-3 mol/1. was developed on the aqueous phase. After removing the solvent chloroform, the glass substrate whose surface had been thoroughly cleaned was moved at a vertical speed of 1.0 mm in a direction across the water surface while keeping the surface pressure constant. The mixed monomolecular film of the DA compound and square aryllium dye was transferred onto the substrate by gently moving up and down at Oc+n/min, and the mixed monomolecular film and the mixed monomolecular cumulative films accumulated in the 21st layer, 41st layer, and 81st layer were transferred to the substrate. An optical recording medium formed on a substrate was created.

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 An optical recording medium was prepared in the same manner as in Example 14, except that 1 part by weight of a diacetylene derivative compound was contained with respect to 10 parts by weight of square lium 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 16 Example 14 except that 1 part by weight of the diacetylene derivative compound was contained per 5 parts by weight of the squarelylium 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 17 An optical recording medium was prepared in the same manner as in Example 14, except that Lfffffi parts of a diacetylene derivative compound were contained per 1 part by weight of square aryllium 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 produced in the same manner as in Example 14, except that only a diacetylene derivative compound was used without using squareylium dye.

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 J recording was performed in the same manner as in Example 1.
This was evaluated. The evaluation of the recording results is shown in Table 3.

Table 3

[Brief explanation of the drawing]

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, FIG. 4 is a schematic cross-sectional view illustrating one embodiment of the structure of an optical recording medium used in the method of the present invention in which the recording layer is formed of a monomolecular film;
The figure is a schematic cross-sectional view illustrating one aspect of the structure of an optical recording medium in which a recording layer is formed of a monolayer cumulative film. 1: Substrate 2: Recording layer 3: Light irradiation (recording) region 4: Laser beam 5: Bit 6: Square lyllium 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 squarylium dye with light according to recorded information to form pits consisting of concave portions in the recording layer. Characteristic optical recording method.