JPS6356495A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain an organic information recording medium having sufficient reflection characteristics, high sensitivity and favorable stability, by incorporating a specified thiapyrene derivative into an information recording layer. CONSTITUTION:A thiapyrene derivative of general formula (I) is incorporated in an information recording layer, in an optical information recording medium comprising the information recording layer on a base. In the formula, each of R1-R8, which may be the same or different, is hydrogen, a halogen or univalent organic residue, with the proviso that at least one of combinations of R1 and R2, R3 and R4, R5 and R6, and R7 and R8 may form a substd. or unsubstd. condensed ring. The base may be, for example, a glass, a vinyl chloride resin, an acrylic resin, an epoxy resin, a vinyl ester resin, a polycarbonate resin or a polyolefin resin. With the optical information recording medium, writing of information can by performed by using He-Ne laser, Ar laser, CO2 gas layer, He-Cd laser or the like, and reproduction of information can be performed by using a low-output He-Ne laser, a low-output Ar laser, a low-output CO2 gas laser, a low-output He-Cd laser, a semiconductor laser or the like.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information recording medium capable of recording and reproducing information using a laser beam, and more specifically, it relates to an optical information recording medium that can record and reproduce information using a laser beam. The present invention relates to an optical information recording medium having an information recording layer.

[Conventional technology and its problems]

Conventionally, the information recording layer of an optical information recording medium having a substrate, an information recording layer, a protective layer, etc., uses a layer containing, for example, an inorganic compound such as a Te alloy or Te oxide, or an organic dye. Among these, organic dyes are generally highly sensitive to lasers, are easy to dispose of, are less likely to cause pollution, and are inexpensive, so various compounds have been studied and attempts have been made to apply them to information recording layers. ing. For example, phthalocyanine dyes, cyanine dyes,
Attempts have been made to use merocyanine dyes, naphthoquinone dyes, etc. in the information recording layer.

However, optical information recording media using these organic dyes have a lower reflectance to reading laser light than those using inorganic compounds, and the ratio of reflectance before and after recording is also small, making it difficult to obtain good contrast. That is, it had the disadvantage that a sufficient C/N ratio could not be obtained during recording and reproduction.

In order to overcome these drawbacks, conventional methods have been adopted in which a reflective film such as a metal film is provided between the substrate and the information recording layer, and the laser beam is irradiated through the protective film provided on the outside of the information recording layer. I didn't get it. However, with these methods, the manufacturing process is very complicated, and recording and playback are performed through a protective layer that is difficult to obtain, and there is a problem that the stability of recording is impaired due to wear and scratches that occur during use. It was born.

For this reason, an organic information recording material with excellent reflective properties is desired, but an organic information recording medium with sufficient reflective properties, high sensitivity, and good stability has not yet been obtained. This is the current situation.

[Failure to solve the problem]

In order to solve the above problems, the present inventors have developed an optical information recording medium having an information recording layer containing a derivative, which responds to laser light with high sensitivity, has excellent stability, and has sufficient reflection for recording and reproduction. The inventors have discovered that the reflectance ratio and the reflectance ratio before and after recording are the same, and have arrived at the present invention.

That is, the present invention provides an optical information recording medium comprising an information recording layer provided on a substrate, in which the information recording layer has the following general formula (
The present invention provides an optical information recording medium containing the thiapyrene derivative represented by I).

R1 (in the formula, R, -R, are each a hydrogen atom, a halogen atom,
or represents a -valent organic residue, and R1 to R8 are the same! , ;
It may be a substituent or a different substituent (and further, at least one combination of R+ and R2, R3 and R4, R5 and R6, R7 and R8 to form a substituted or unsubstituted condensed ring) ) Specific examples of the thiapyrene derivative represented by the above general formula (1) are listed below, but the present invention is not limited thereto.

1,6-cythiapyrene, 3,8-diphenyl-1゜6-
Cythiapyrene, 3,8-dimethyl-1,6-cythiapyrene, (bis-1-ethanedithio)-1,6-cythiapyrene, 3.8-(bisthiophenyl)-16-cythiapyrene, 2.7-(bisthiophenyl) 'I-1,6-cythiapyrene, 2゜7-(bisthiomethyl) -R6-
Cythiapyrene, 2,7- (bis-2-thiofuran)
-1,6-Sithiabirene The above compound has high solubility in solvents and polymeric resin binders, can be easily formed into a coating film, and has the vapor pressure necessary for vacuum deposition, so it can be used by vacuum deposition, sputtering, etc. law,
The film can be formed on the substrate by a general thin film forming method such as a doctor blade method, a casting method, a spinner method, or a dipping method. Among these, the casting method is preferred from the viewpoint of ease of process, and the vacuum evaporation method is preferred when particularly excellent reflective properties are required. It goes without saying that even if the casting method is used, the coating film still has the reflective properties necessary for recording and reproduction.

Examples of the substrate used in the present invention include glass, vinyl chloride resin, acrylic resin, epoxy resin, vinyl ester resin, polycarbonate resin, and polyolefin resin.

In addition, examples of the polymer resin binder used when forming a film by the casting method include gelatin, cellulose derivatives, natural polymer compounds such as rosin, polyethylene, polypropylene, polystyrene, poly(meth)acrylate, polyester, and polyurethane. , thermoplastic resins such as vinyl chloride polymers.

In addition, the blending ratio of the thiapyrene derivative and the polymer resin binder in the information recording layer according to the present invention is 80% by weight.
The ratio is preferably 20:20 to 20:80, more preferably 70:30 to 30:70.

In addition, general-purpose solvents such as THF, methylene chloride, chloroform, carbon tetrachloride, benzene, and toluene can be used. Three media can be used.

The thickness of the information recording layer on the substrate is not particularly limited, but from the viewpoint of sensitivity to laser light, it is preferably 0.1 to 5 -, more preferably 0.5 to 2 / /I11. In addition, in the vacuum evaporation method, the thickness is preferably 0.01 to 0.5μ, more preferably 0.05 to 0.2μ.

Furthermore, a protective layer can be provided on the information recording layer. The protective layer is preferably made of a material that is transparent to laser light, has high mechanical strength, does not react with the recording layer, and has good film formability. For example, Al2O! .

5in2. MgO+ ZnO+ MgFz+ CuF
Inorganic compounds such as polystyrene, polyester, polycarbonate, polyxylene, polyvinyl chloride, polyacrylonitrile, polyacrylonitrile, poly(meth)acrylate, polyvinyl acetate, polyethylene, polypropylene, polyamide, etc. Can be mentioned.

The optical information recording medium thus obtained can be used for writing on I! e-Ne laser, meter laser, carbon dioxide laser, He-Cd laser, etc. can be used,
For reproduction, a low power He--Ne laser, a low-power Ar laser, a low-power carbon dioxide laser, a low-power He-Cd laser, a semiconductor laser, etc. can be used.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example I J, Hachim, Chen+, Soc, 108349
1.6- according to the method described in 0 (1986)
Cythiapyrene was synthesized.

The maximum absorption wavelength of the obtained product was 454 nm.

Polycarbonate was dissolved in a methylene chloride solution of this product to make a 50% solution, and this solution was coated on a glass substrate so that the solid content was Ig/cm'' to obtain an optical information recording medium.

The reflectance of the thin film surface of this information recording medium was 30%.

Furthermore, when a He-Cd laser (oscillation wavelength 442 nm) was irradiated with a beam diameter of 2.0 tin and the irradiation power on the irradiated surface was set to 101, the results were observed using an electron microscope.
Extremely clear grooves are formed, and the reflectance of the irradiated area is 1.
It had decreased to 0%.

Example 2 1,6-cythiapyrene obtained in Example 1 was vacuum deposited on a glass substrate to obtain an optical information recording medium.

The reflectance of the thin film surface of this information recording medium was 35%.

When the same evaluation as in Example 1 was performed, clear grooves were confirmed, and the reflectance of the irradiated area was reduced to 14%.

Example 3 In the method of Example 1, 3,8-diphenyl-1°6-cythiapyrene was synthesized using phenacyl bromide.

The maximum absorption wavelength of the obtained product was 456 nm. Polycarbonate in methylene chloride solution of this thing? 3 answers, 50%? This material was coated onto a glass substrate so that the solid content was Ig/cm" to obtain an optical information recording medium.

The reflectance of the thin film surface of this information recording medium was 30%.

Furthermore, using a He-Cd laser (oscillation wavelength 442 nm) with a beam diameter of 2.0-, the irradiation power at the irradiation surface was set to lQm.
When irradiated at H and observed with an electron microscope, extremely clear grooves were formed, and the reflectance of the irradiated area was 10%.
It had decreased to

Example 4 3,8-diphenyl-1,6-cythiabirene obtained in Example 3 was vacuum deposited on a glass substrate to obtain an optical information recording medium.

The reflectance of the thin film surface of this information recording medium was 35%.

When the same evaluation as in Example 3 was performed, clear grooves were confirmed, and the reflectance of the irradiated area was reduced to 13%.

Example 5 1,6-cythiapyrene obtained in Example 1 was reacted with n-butyllithium and further with diphenyl disulfide to give 2.7
-(Bisthiophenyl)-1,6-dithiapyrene was synthesized.

The maximum absorption wavelength of the obtained product was 477 nm. Polycarbonate was dissolved in this benzene solution to make a 50% solution, and this solution was coated on a glass substrate so that the solid content was Ig/cm'' to obtain an optical information recording medium.

The reflectance of the thin film surface of this information recording medium was 31%.

Furthermore, a 1le-Cd laser (oscillation wavelength 442 nm) was used with a beam diameter of 2.0p, and the irradiation power at the irradiation surface was 10m.
When irradiated with W and observed with an electron microscope, extremely clear grooves were formed, and the reflectance of the irradiated area was 10%.
It had decreased to

Example 6 2,7-(bisthiophenyl)-1, obtained in Example 5
6-dithiapyrene was vacuum deposited on a glass substrate to obtain an optical information recording medium.

The reflectance of the thin film surface of this information recording medium was 37%.

When the same evaluation as in Example 5 was performed, clear grooves were confirmed, and the reflectance of the irradiated area was reduced to 15%.

Example 7 1,6-dithiapyrene obtained in Example 1 was reacted with n-butyllithium and further with bis-2-thiofuranyl disulfide to obtain 2,7-(bis-2-thiofuran)-1,6-
Dithiapyrene was synthesized.

The maximum absorption wavelength of the obtained product was 478 nm. Polycarbonate was dissolved in this solution, and 50%
Make a solution and place this on a glass substrate with a solid content of Ig/c.
A'' was coated to obtain an optical information recording medium.

The reflectance of the thin film surface of this information recording medium was 30%.

Furthermore, )le -Cd laser (oscillation wavelength 442r+m
) was irradiated with a beam diameter of 2.0 tm and an irradiation power of 10 mW on the irradiated surface, and when observed with an electron microscope, extremely clear grooves were formed, and the reflectance of the irradiated area was 9%. It had decreased to

Example 8 2,7-(bis-2-thiofuran)- obtained in Example 7
1,6-dithiapyrene was vacuum deposited on a glass substrate to obtain an optical information recording medium.

The reflectance of the thin film surface of this information recording medium was 39%.

When the same evaluation as in Example 7 was performed, clear grooves were confirmed, and the reflectance of the irradiated area was reduced to 14%.

Claims (1)

[Scope of Claims] An optical information recording medium comprising an information recording layer provided on a substrate, characterized in that the information recording layer contains a thiapyrene derivative represented by the following general formula (I). optical information recording medium. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, R_1 to R_8 each represent a hydrogen atom, a halogen atom, or a monovalent organic residue, and R_1 to R_8 are each the same substituent. may be a different substituent,
Furthermore, R_1 and R_2, R_3 and R_4, R_5 and R_6
, R_7 and R_8 may form a substituted or unsubstituted fused ring. )