JPH0478471B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an optical information recording medium, and particularly to a write-once optical information recording medium using a heat mode. [Prior Art] A heat mode write-once optical recording medium is used as a means for recording and reproducing data such as images such as characters and figures or audio. This heat mode write-once optical recording medium is
For example, it is created by vacuum-depositing a low-melting point metal such as tellurium on an insulating substrate, and when recording on this material, the signal of the image taken with a camera is transferred to, for example, a semiconductor laser or a helium or neon laser. etc., and irradiates the vacuum-deposited tellurium film to change the reflectance of the film to form a pattern of differences in reflectance corresponding to the image signal. On the other hand, when reading out the data, the difference in reflectance is detected by scanning with a weak laser beam, and this signal is converted into an image signal to display an image. Incidentally, recently, instead of using the vapor-deposited film of tellurium as described above, organic dyes such as vanadyl phthalocyanine and cyanine dyes, which have lower reflectance than metals but relatively high reflectance among organic dye materials, have been used in the recording layer. Optical information recording media, which used to be popular in the past, are now attracting attention. The reason for this is that the recording layer can be formed using a coating method called spin coating, which uses the centrifugal force of rotation to spread the paint dripped onto the substrate over the surrounding area.This makes it easy to manufacture without using a vacuum system. It has excellent properties such as being able to increase productivity, being resistant to oxidation and not corroding, and being able to heat locally without affecting the surrounding areas due to its low thermal conductivity, making it suitable for high-density recording. It depends. In particular, cyanine dyes have attracted attention because they exhibit high absorption and reflection in the wavelength range of 700 to 900 nm of semiconductor laser light. [Problems to be Solved by the Invention] However, in an optical information recording medium having a conventional cyanine dye-based recording layer on a plastic substrate, the wavelength showing the maximum reflectance and the wavelength showing the maximum absorption do not match. If the wavelength exhibiting the maximum reflectance is made to match the recording laser wavelength, absorption will decrease, making it difficult to perform stable recording with a low-power laser. Therefore, a recording layer that can match the wavelength of maximum absorption to the recording laser wavelength has been used. The cyanine dye-based recording layer exhibits high reflectance, and as a result, a large reproduction output can be obtained, which greatly reduces the burden on the reproduction system, and also has the advantage of being compatible with conventional reproduction-only optical discs. Therefore, in order to take advantage of these properties, it is desirable to use an appropriate light-absorbing substance in combination. From this point of view, Japanese Patent Application Nos. 62-197153 and 197154 disclose an optical information recording medium having an optical recording layer using a recording laser light-absorbing substance in combination with a cyanine dye.
It was proposed in the specification of the issue. Since the wavelength of the recording laser light is 670 to 850 nm (radius laser), the recording laser light-absorbing materials shown in these specifications have the following general formula [ ] The substances shown in [ ] are listed. (However, M represents Ni, Cu, Co, Pd or Pt,
Y ₁ and Y ₂ are either S, O, or NH, and may be the same or different, and C ₁ and C ₂ are substituted or unsubstituted benzene rings, alkyl groups, and cyano groups. They may be the same or different, and both may be bonded via a cyclic hydrocarbon to form a benzene ring, a saturated 6-membered ring, etc., and R ₁ ' represents an alkyl group. , N(R ₁ ') ₄ may be omitted when an anion is not formed by Y ₁ , Y ₂ , C ₁ and C ₂ . ) (However, n is a value of 1, 2, 3, or 4, R ₂ ' is a hydrogen atom or an alkyl group, and X ₁ ^- is a halogen atom, perchloric acid, hydroborofluoric acid, hexafluoro Acetic acid, antimony fluoride,
Represents an anion such as arsenic fluoride. ) On the other hand, dyes used in combination with these substances include cyanine dyes whose methine chain is pentamethine, AlCl phthalocyanine and its substituted products, quinocyanine dyes whose methine chain is pentamethine, squarylium dyes, There are many types of pigments, such as croconic metine pigments, pyrylium pigments, azulenium pigments, and tetradehydrocholine pigments. However, these cyanine dyes and the substance represented by the above general formula [] [] can be mixed and dissolved in a solvent to prepare a solution, which can be applied by spin coating to form a recording layer. The combinations of these dyes and substances are limited, and the appropriate combination of this system that has both the above-mentioned absorption of the recording laser beam and reflection of the reproduction laser beam is not yet known. . For example, a compound represented by the following general formula [] that belongs to the above general formula [] [R ₃ ' is H or a dialkylamino group] When preparing a coating solution to be applied by spin coating, the solvent that is dissolved together with the cyanine dye is usually used, such as ethanol, acetylacetone, hydroxyacetone,
Methyl cellosolve, ethyl cellosolve, methanol, dichloroethane, methyl ethyl ketone, etc. have low solubility in these and are difficult to use.Also, when dissolving in a solvent with relatively good solubility such as dimethylformamide, the coating solution Since it is necessary not to melt the substrate when it is applied to the substrate, there is a problem in that it can only be used for substrates made of limited materials such as glass. The purpose of the present invention is to improve the solubility of a compound of the general formula [] that has absorption in the wavelength region of 670 to 850 nm, and to prepare a coating liquid using it in combination with an organic dye having a maximum reflectance in this wavelength region. To provide an optical recording medium that enables the formation of a recording layer by a spin coating method using the same, has a high reflectance for laser light in this wavelength range, and has an absorbency suitable for a low power laser. It is in. [Means for Solving the Problems] In order to achieve the above object, the method for producing an optical information recording medium of the present invention includes adding a compound represented by the following general formula [] together with the organic dye to a solvent that dissolves the organic dye. The present invention is characterized by the steps of producing a coating liquid containing a dissolved compound, and applying the coating liquid onto a substrate. [However, R ₁ to R ₁₂ are H, OCH ₃ , OC _o H _2o+1 (n
= 2, 3..., 8), and
Contains at least two OC _o H _2o+1 (n=2, 3..., 8). ] Furthermore, as the organic dye, it is preferable to use a cyanine dye whose methine chain is composed of pentamethine. Next, the present invention will be explained in detail. The metal complex of the compound of the above general formula [] used in the present invention preferably has good absorbency in the wavelength range of 670 nm to 850 nm, particularly in the wavelength range longer than 700 nm, and among the substituents R ₁ to R ₁₂ contains at least two OC _o H _2o+1 (n=2, 3..., 8), so it can be easily dissolved in a solvent such as the alcohol that dissolves the organic dye. Furthermore, examples of the organic dye used in the present invention include compounds represented by the following general formula []. (However, l=2, or methine chain (-(CH=
The hydrogen atom of CH) _l -CH=) may be substituted with a halogen atom, an alkyl group, an alkoxy group, a diphenylamino group, etc., and may have a substituted or unsubstituted cyclic side chain spanning multiple carbon atoms. Also good,
Z and Z' are atomic groups forming a benzene ring or naphthalene ring, and may be the same or different,
R ₁₃ and R ₁₃ ′ are substituted or unsubstituted alkyl groups such as halogen, alkoxy groups, hydroxy groups, carboxyl groups, allyl groups, alkylhydroxy groups, aralkyl groups, alkenyl groups, alkylcarboxyl groups, alkylsulfonyl groups, or alkali An alkylcarboxyl group or an alkylsulfonyl group bonded to a metal or an alkyl group, which may be the same or different, and (Ri)m and (R'i)n are m, respectively.
n indicates the number of substituents, m and n are integers of 1 to 4, and Ri and R'i are general formulas each indicating a different substituent in which i can take from 2 to 5; an alkyl group, an alkoxy group, halogen atom, hydrogen atom, sulfonamino group, sulfonealkylamino group, nitro group, amino group,
n represents the same or different substituent arbitrarily selected from the above Ri and R′i according to the number of m and n, respectively, and (Ri)m(R′i)n may be interchanged. can also be used, X ₂ ^- is a halogen atom,
perchloric acid, hydroborofluoric acid, benzenesulfonic acid, toluenesulfonic acid, alkylsulfonic acid,
It represents an anion such as benzenecarboxylic acid, alkylcarboxylic acid or trifluoromethylcarboxylic acid, and when R ₁₃ and R ₁₃ ' have a group bonded to an alkali metal, X ^- ₂ may not be present. ) Specifically, the specification of Japanese Patent Application No. 62-11300,
Specifications No. 62-195793 to 195799, patent application No. 62-197153
-197154 can be mentioned. Further, compounds represented by the following general formula [] can also be used, but the invention is not limited thereto. In the formula, R ₁₃ and R ₁₃ ′X ^- ₂ are the same as in the general formula [], and A
consists of the following:

【formula】

【formula】

【formula】

【formula】 [Effect]

OC _o as a substituent of the compound of the above general formula []
Since two or more H _2o+1 (n=2, 3..., 8) are introduced, the solubility in organic solvents is improved.
With such good solubility in solvents, it is possible to prepare a coating liquid in which organic dyes are dissolved in a solvent, and this coating liquid can be used to uniformly coat a resin substrate, allowing recording on an optical recording layer containing this compound. By imparting laser light absorption properties, it is possible to compensate for the lack of absorption properties of organic dyes. [Example] Next, the present invention will be explained in detail based on an example. Example 1 Ni-bis(3,3',5,5'tetramethoxy4,
4'diethoxydithiobenzyl) 1% by weight, 1,1'-diethyl 3,3,3',3'-
Tetramethyl 5,6,5',6'tetramethoxyindodicarbocyanine perchlorate A coating solution prepared by dissolving 4% by weight of methanol was applied to an injection-molded acrylic substrate with pregrooves using a spinner to form an optical recording layer of 700 Å. In this completed state, the optical recording layer is coated with a wavelength of 780n.
When recording was performed using a laser beam of 500 KHz and a linear velocity of 1.2 m/s, the optimum recording power was 3.2 m.
It was mW. Output this recorded signal 0.3m
When I read it with the W laser, the C/N was
It was 53dB. Example 2 Ni-bis(3,3',5,5'tetramethoxy4,
4′dipropoxydithiobenzyl) 0.5% by weight, 1,1'-dibutyl 3,3,3',3'-
Tetramethyl 10-chloro-9,11-ethylene 4,
5,4′,5′dibenzoindodicarbocyanine perchlorate was dissolved in 4% by weight hydroxyacetone and applied using a spinner to an acrylic substrate with pregroups injection molded in the same manner as in Example 1 to form an optical recording layer of 670 Å. When recording and reproduction were performed on the optical recording layer in the same manner as in Example 1 in this completed state, the optimum recording power was 3.4 mW, and the C/N during reproduction was
It was 50dB. Example 3 Ni-bis(3,3',5,5'tetramethoxy4,
4'dioctoxydithiobenzyl) 0.8% by weight, Example 1: 3.5% by weight of 3,3'-diethyl 9,11-neopentylene dicarbocyanine iodide (product number NK1836, manufactured by Nippon Kanko Shiki Kenkyusho) was dissolved in benzyl alcohol and prepared using a spinner.
It was applied to a pregrooved acrylic substrate that had been injection molded in the same manner as above to form an optical recording layer of 750 Å. When recording and reproduction were performed on the optical recording layer in the same manner as in Example 1 in this completed state, the optimum recording power was 2.8 mW, and the C/N during reproduction was
It was 50dB. Comparative Example 1 In Example 1, Ni-bis(3,3',5,
An optical recording layer was formed on an acrylic substrate in the same manner except that 5'tetramethoxy4,4'diethoxydithiobenzyl) was not used. When recording and reproducing were performed on the optical recording layer in the same manner as in Example 1 in this completed state, the optimum recording power was 4.4 mW, and the C/N during reproduction was 47 dB.
It was hot. Comparative Example 2 In Example 1, Ni-bis(3,3',5,
In the above general formula [], instead of 5'tetramethoxy4,4'diethoxydithiobenzyl),
An optical recording layer was formed on an acrylic substrate in the same manner except that a Ni compound in which R ₁ to _{R 12} were H was used. In this finished optical recording layer, insoluble matter of the Ni compound was observed, and the coating layer was non-uniform. When this optical recording layer was recorded with a laser and reproduced in the same manner as in Example 1, it was not possible to perform recording and reproduction that could be used for practical purposes. Comparative Example 3 In Example 1, Ni-bis(3,3′,5,
In the above general formula [], instead of 5'tetramethoxy4,4'diethoxydithiobenzyl),
An optical recording layer was formed on an acrylic substrate in the same manner except that a Ni compound in which R ₁ to R ₁₂ were CH ₃ was used. In this finished optical recording layer, insoluble matter of the Ni compound was observed, and the coating layer was non-uniform. When this optical recording layer was recorded with a laser and reproduced in the same manner as in Example 1, it was not possible to perform recording and reproduction that could be used for practical purposes. [Effects of the Invention] According to the present invention, since the compound represented by the above general formula [] with improved solubility in a solvent is used in combination with an organic dye, the above general formula [] is added to a solvent that dissolves the organic dye. A coating liquid can be prepared by dissolving the compound represented by the formula, and when a coating layer is formed on a conventionally commonly used substrate by, for example, spin coating, the organic dye and the compound of the general formula [] are mixed together. A uniformly mixed optical recording layer is obtained. This allows the optical recording layer to e.g.
By combining the good reflectivity of the cyanine dye with respect to 780 nm laser light and the good absorbency of the metal complex of the general formula [], it is possible to provide an optical information recording medium with excellent recording characteristics and reproduction characteristics.

Claims (1)

[Scope of Claims] 1. A coating solution is prepared by dissolving and containing a compound represented by the following general formula [] together with the organic dye in a solvent that dissolves the organic dye, and the coating solution is applied onto a substrate. A method for manufacturing an optical information recording medium, comprising a step of coating. [However, R ₁ to R ₁₂ are H, OCH ₃ , OC _o H _2o+1 (n
= 2, 3..., 8), and
Contains at least two OC _o H _2o+1 (n=2, 3..., 8). 2. The method for producing an optical information recording medium according to claim 1, wherein the organic dye is a cyanine dye whose methine chain is composed of pentamethine.