JPH055676B2 - - 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] Heat mode recordable optical information recording media have been 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, 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 senior dye-based recording layer on a plastic substrate, the wavelength showing maximum reflectance and the wavelength showing 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 this property, 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 concerning optical information recording media having an optical recording layer using a recording laser light-absorbing substance in combination with a cyanine dye.
proposed in the specification. Since the wavelength of the recording laser light is 670 to 850 nm (semiconductor 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, and Y ₁ and Y ₂ are either S, O, or NH, and may be the same or different types, and C ₁ , C ₂ is one type of a substituted or unsubstituted benzene ring, an alkyl group, or a cyano group, and may be the same or different, and both are bonded via a cyclic hydrocarbon to form a benzene ring, a saturated 6-membered A ring, etc. may be formed, R ₁ ′ represents an alkyl group, and N(R ₁ ′) ₄ may be omitted when an anion is not formed by Y ₁ , Y ₂ , C ₁ , and C ₂ good.) (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 dyes and the above general formula [],
There are a limited number of combinations of these dyes and substances that can be mixed with the substances shown in [ ] and dissolved in a solvent to prepare a solution, which can be applied by spin coating to form a recording layer. Furthermore, in this system, a suitable combination of both the recording laser light absorption property and the reproduction laser light reflection property described above has not yet been 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 used to dissolve it together with the cyanine dye is commonly used ethanol, acetylacetone, or hydroxyl. acetone,
Methyl cellosolve, ethyl cellosolve, methanol, dichloroethane, methyl ethyl ketone, etc. have low solubility in these substances and are difficult to use.Also, when dissolving in a solvent with relatively good solubility such as dimethylformamide, it is difficult to use the optical recording layer. Since it is necessary not to melt the substrate when it is formed by coating on the substrate, there is a problem 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 maximum reflectance in this wavelength region. The present invention enables the formation of a recording layer by a spin coating method using the same, and provides an optical information recording medium that has a high reflectance for laser light in this wavelength range and has an absorbency suitable for low power lasers. There is a particular thing. [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 any group of H, OCH ₃ , OC ₂ H ₅ , or OC ₃ H ₇ except when all are H, and X ⁺ represents a quaternary ammonium cation. ) The organic dye is preferably a cyanine dye in which the methine chain is composed of pentamethine. Next, the present invention will be explained in detail. The compound of the above general formula [] used in the present invention preferably has good absorption in the wavelength range of 670 to 850 nm, particularly in the wavelength range longer than 700 nm, and is a quaternary ammonium salt. It can be made easily soluble in solvents such as the alcohols mentioned above that dissolve organic dyes. The quaternary ammonium salt of the general formula [] is given by Inorg.
Chem, 2, 6, 1227 (1963). Examples of the organic dye used in the present invention include compounds represented by the following general formula []. (However, l=2, and 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 atoms, alkoxy groups, hydroxy groups, carboxyl groups, allyl groups, alkylhydroxy groups,
Aralkyl group, alkenyl group, alkylcarboxyl group, alkylsulfonyl group, or an alkylcarboxyl group or alkylsulfonyl group bonded to an alkali metal or alkyl group, which may be the same or different, (R _i ) _n , (R′ _i ) _o is 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 (R _i ) _n , (R' _i ) _o
represents the same or different substituents arbitrarily selected from the above R _i and R' _i according to the numbers of m and n, respectively,
(R _i ) _n and (R' _i ) _o can be interchanged or the same, and X ^- ₂ is a halogen atom, perchloric acid, hydroborofluoric acid, benzenesulfonic acid, toluenesulfonic acid, alkylsulfone represents an anion such as acid, benzenecarboxylic acid, alkylcarboxylic acid or trifluoromethylcarboxylic acid,
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. 1983-11300,
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 , R ₁₃ ′, X ^- ₂ are the same as in the general formula [],
A consists of:

【formula】

【formula】

【formula】

【formula】

[Effect]

Since the compound of the above general formula [] was made into a quaternary ammonium salt, its solubility in solvents was improved.
When the solubility in solvents is improved in this way, 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, and an optical recording layer containing this compound can be coated uniformly on a resin substrate. It can provide recording laser light absorption and compensate for the lack of absorption of organic dyes. [Example] Next, the present invention will be explained in detail based on an example. Example 1 Ni-bis(4,4'dimethoxydithiobenzyl)
Tetrabutylammonium 1% by weight, 1,1'-diethyl 3,3,3',3'-
Tetramethyl 5,7,5',7'tetramethoxyindodicarbocyanine iodide A coating solution prepared by dissolving 4% by weight of each in 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, a wavelength of 780 nm is applied to the optical recording layer.
irradiate with a laser of 500KHz and a linear velocity of 1.2m/sec,
When recording, the optimal recording power was 3.3mW
It was hot. When this recorded signal was read by a laser with an output of 0.3 mW, the C/N was 52 dB. Example 2 Ni-bis(3,3',4,4',5,5'hexamethoxydithiobenzyl)tetrabutylammonium 0.5% by weight, 1,1'-dibutyl 3,3,3',3'-
Tetramethyl 4,5,4',5' dibenzoindodicarbocyanine perchlorate (product number NK3219 manufactured by Japan Photosensitive Color Research Institute) A coating liquid was prepared by dissolving 4% by weight of each in 1,2-1 dichloroethane, and this was applied using a spinner to an epoxy substrate on which a pre-blue was formed to form an optical recording layer of 650 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 hot. Comparative Example An optical recording layer was formed on an acrylic substrate in the same manner as in Example 1 except that Ni-bis(4,4'-dimethoxydithiobenzyl)tetrabutylammonium was not used. In this completed state, recording was performed on the optical recording layer in the same manner as in Example 1, and when it was reproduced, the optimum recording power was 4.4 mW and the C/N was 47 dB. [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, this general formula [] can be used in a solvent that dissolves the organic dye. A coating liquid can be prepared by dissolving the compound represented by the formula, and when this is used to form a coating layer on a commonly used substrate by spin coating, organic dyes and the above general formula [] are combined. An optical recording layer in which the compounds are uniformly mixed 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 compound of the general formula [], it is possible to provide an optical information recording medium with excellent recording characteristics and reproduction characteristics.

Claims (1)

[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 any group of H, OCH ₃ , OC ₂ H ₅ , or OC ₃ H ₇ except when all are H, and X ⁺ represents a quaternary ammonium cation. 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.