JPS60259498A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To provide the functions of recording and regeneration for a recording medium as well as raise the recording sensitivity and S/N ratio of the medium by forming a thin film layer containing a specific triarylaluminium salt on a base plate. CONSTITUTION:A base plate has a thin film layer containing a triarylaluminium salt of the formula (1) (where R1, R2, R3, R4, R5, and R6 are each coincidently or differently H, an alkyl, aralkyl, phenyl, or substituted phenyl group and L is an anion). The triarylaluminium salt is easily soluble in various kinds of solvents and capable of easily forming thin films.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information recording medium for recording and reproducing information by causing a state change using a high density energy beam such as a laser beam.

Inorganic compounds such as bismuth, tellurium, and low tellurium oxides are well known as materials for optical information recording media.

Although these have high recording sensitivity and high contrast, they have high melting points and thermal conductivities, low specific heat, and are subject to significant deterioration due to air oxidation in the atmosphere. In addition, many of these materials have a surface reflectance of 50% or more, and the energy of the laser beam cannot be used effectively, so the optical energy required for recording is large, and therefore it is difficult to record with high-speed scanning. This method requires an output laser beam, which has the disadvantage that the recording device becomes large and expensive.

On the other hand, organic dye compounds have low thermal conductivity, and therefore can effectively utilize the energy of laser light, and have the property that their absorption rate is maximum at a specific wavelength. It has the advantage of allowing a wide selection of recording media. Therefore, attempts have been made to overcome the drawbacks of inorganic compounds by using organic dye compounds as materials for optical information recording media, and various recording media have been proposed so far.

In particular, many organic compounds have been studied because they have the advantage of being easily mass-produced because they can be dissolved in a solvent and made into thin films by coating methods such as spin cording and dipping.

For example, cyanine dye (Japanese Patent Application Laid-Open No. 58-114989), Sudan Black B (Japanese Patent Application Laid-Open No. 54-87789)
Rhodamine 6G (Japanese Unexamined Patent Publication No. 56-16948), Phthalocyanine (Unexamined Japanese Patent Publication No. 55-97088), Naphtoki, non-based pigment (Unexamined Japanese Patent Application No. 58-112)
No. 798), etc. have been proposed.

These organic dyes can form thin films from solution1.
Generally, they have low solubility and have the disadvantage that it is difficult to obtain a highly concentrated bath solution. Therefore, the film thickness can only be thin, and the film thickness cannot be freely selected.

Moreover, since the solvents that can be dissolved are also limited, there are restrictions on the substrate materials that can be applied. That is, it is generally used as a substrate material (
Many pigment materials are only soluble in solvents that attack the methacrylic resin plates used.

In view of the above-mentioned drawbacks of organic dyes, the inventors of the present invention made extensive studies and found an organic dye material that has excellent solubility and is easy to form a thin film.

An object of the present invention is to provide an optical information recording medium having recording and reproducing functions, higher recording sensitivity, and higher S/N ratio.

That is, the present invention provides a substrate with the general formula (1) (wherein, Rr, Rg, Rs, R4, R6, R
6 is the same or 1\ is different hydrogen, alkyl group, aralkyl group, phenyl group,
In the substituted phenyl group, L represents an anion. ) This is an optical information recording medium characterized by having a thin axillary layer containing a triarylaminium layer represented by:

The substrate materials used in the present invention are those well known to those skilled in the art and are transparent to the laser beam used. Examples include glass, quartz, and plastics, with plastics being particularly preferred in terms of safety, light weight, and improved recording sensitivity. Typical plastics include polyvinyl chloride, polyvinyl acetate, polyacrylate, polymethacrylate, polyester,
Examples include nitrocellulose, polyethylene, polypropylene, polyamide, polystyrene, polycarbonate, polysulfone and epoxy resin. These include common homopolymers and copolymers.

Furthermore, when writing and reading are performed from the coating side, metal such as an aluminum plate can be used as the substrate material.

The triarylamine field used in the present invention has the general formula (1
) (In the formula, R1, R2, R1, R4, R5, R6 are the same or different hydrogen, alkyl group, aralkyl group, phenyl group, substituted phenyl group, and L represents an anion.) It is a compound that has excellent solubility in solvents and can easily form a thin film.

Specific examples of R1-R6 include the following.

Hydrogen, alkyl groups include methyl, ethyl, propyl,
isopropyl, n-butyl, jso-butyl, tert
-1 carbon number such as butyl, hexyl, octyl, lauryl, etc.
A straight-chain or branched hydrocarbon residue having ~20 hydrocarbon residues, and a haloalkyl group in which part or all of the hydrogens of the hydrocarbon residue are substituted with halogens such as chlorine, fluorine, and bromine;
Aralkyl groups and [7 are benozyl, P-methylbenzyl, phenethyl, etc.; phenyl groups and substituted phenyl groups include phenyl groups, P-methylbenzyl, phenethyl, etc. , phenyl, p-
Examples include methylphenyl, p-chlorophenyl, 2,4-dimethylphenyl, p-dimethylaminophenyl, and the like.

Examples of the anion of L include perchlorate ion (Cz04
), fluoroborate ion (BF4) trifluoroacetate ion (CFaCOO-), ) dichloroacetate ion (CC45COO), picrate ion ((No2)
gcsHgcOO), hexafluoroarsenate ion (Ag
F2 ), hexachloroantimonate ion (5bCz
s ), hexafluoroantimonate ion (SbFa
-), benzenesulfosic acid ion (C@Hs 5Os-
), alkyl sulfonate ion (R50a), phosphate ion (P04'), sulfate ion (SO4), chloride ion <ct, ), bromide ion (Br), iodine ion (
I-) etc.

Among them, CtO<-1SbFa-1ASF6-1BF4-
is preferable because it provides excellent solubility of the salt produced.

Tris(4-dimethylaminophenyl) as A side
Aminium iodide, tris(4-dimethylaminophenyl) aminium hexafluoroantimonate,
Tris (4-diethylaminophenyl) aminium hexafluoroantimonate, tris (4-dibutylaminophenyl) aminium verchlorate, tris (4-
dibenzylaminophenyl) aminium verchlorate, tris(4-benzylaminophenyl) aminium hexafluoroarsenate, tris(4-dioctylaminophenyl) aminium hexafluoroantimonate, tris(4-dilaurylaminophenyl) aminium Examples include nium barchlorate. These aminium salts have excellent solubility and have the advantage of being easy to form into thin films depending on the coating method.

For example, alcohol-based threads such as ethanol, methanol, and isopropyl alcohol, ketone threads such as acetone and methyl-ethyl ketone, ether-based threads such as tetrahydrofuran and dioxane, cellosolve threads such as ethyl cellosolve and methyl cellosolve, and chlorinated carbonized threads such as chloroform dichloromethane. Soluble in hydrogen-based solvents, dimethylformamide, dimethylsulfoxide, etc.

The above triarylaminium salt is, for example, 0°Neunh
oeffer, et, al, ; Chemis
che Berichte vol. 92, p. 245 (1959
It can be easily obtained by oxidizing the corresponding triarylamine with iodine, silver berchlorate, silver hexafluoroantimonate, silver tetrafluoroborate, etc., as described in 2010).

A thin film of a triarylaminium salt can be easily obtained by dissolving the triarylaminium salt in the above solvent, coating it on a substrate, and drying it.1 In particular, a triarylaminium salt alone cannot be formed into a homogeneous thin film. Unlike conventional dyes, it does not require the addition of a binder such as nitrocellulose.

The thickness of the triarylaminium salt thin film layer used in the optical information recording medium of the present invention is 100A to 1 μm. If the film thickness is less than 100 A, the reflectance is insufficient and it is difficult to read the recorded information. If the film thickness is greater than 1,000 l It,m, the reflectance will be high, but the optical energy required to record information will be large. The film thickness that can achieve particularly high sensitivity as a recording medium is 400. Polymethyl acrylate or polymethyl methacrylate may be used as appropriate to improve the adhesion between the formed coating film and the substrate, the stability of the coating film, and economic efficiency. Organic polymer compounds such as acrylic resins such as acrylic resins such as nitrocellulose, cellulose derivatives such as acetylcellulose, vinyl resins such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymers may be added.

The amount of these organic polymer compounds added is from 0 to 50% by weight based on the triarylamine lamb salt, and usually from 0 to 50% by weight.
30% by weight is preferred. If the addition ratio is large, the reflectance of the coating film will be low, making it difficult to obtain a sufficient optical density difference.

Any known coating method may be used, such as a spin code method, a dipping method, a bar coater method, a roll coater method, and the like. The spin cord method is preferable for disc-shaped substrates.

The laser beam applied to the optical information recording medium of the present invention must be selected depending on the absorption wavelength of the dye. However, the compound of the present invention has a large molar absorption coefficient, and the wavelength of laser light that is slightly deviated from the maximum absorption wavelength ranges from 700 nm to 90 nm.
0 nm, and the optical information recording medium of the present invention is suitable for a semiconductor laser.

Irradiating the optical information recording medium of the present invention with a laser beam;
In order to perform laser recording, use a laser beam with a wavelength in the absorption wavelength range of the doria (lylaminium salt) selected from various semiconductor lasers, \lium neon lasers, etc. The beam is focused into a spot beam of usually 2 μm or less and irradiated onto the recording medium.

The optical information recording medium of the present invention is capable of obtaining an extremely high density and optically high density difference using a low-output laser beam, and that the laser beam used for recording can be directly reduced in output and used as a reading light. It has the advantages of being a real-time recording that does not require post-processing such as developing and fixing, and that there is no need for darkroom operations because it is not exposed to room light. It can be widely applied to original plates for phototypesetting, optical video discs, optical audio discs, etc.

Examples will be given below to explain the present invention more specifically, but the present invention is not limited thereto.

To measure the film thickness below 1000 yen, we used a TalysSep manufactured by Taylor-Hobsoh, and to measure the spectral value, we used a spectrophotometer UV-865 manufactured by Takafusa Seisakusho.
1.

Example 1 0.5 part of tris(4-diethylaminophenyl)aminium fluoroantimonate was dissolved in 100 parts of tetrahydrofuran, filtered through a 0.2 μm membrane filter, and then mixed with a 50 wet Ω glass using a spinner. It was applied onto a plate and dried under predetermined conditions to form a thin film of about 50 OA. The visible and near-infrared transmission spectrum and reflection spectrum of this thin film were measured, and λmax, 880
The optical density (0, D, ) and reaction rate at part m were calculated.

Next, the glass plate was rotated at a constant speed of 1200 rpm using the apparatus shown in FIG.
Writing was performed at KHz and the recording sensitivity was measured.

These results are shown in Table 1.

Examples 2 to 4, Example 1 The same triarylaminium salt used in Example 1 and various binders were mixed in various proportions and spin-coded onto a glass plate to form a thin film.

As in Example 1, λmax, optical density (U, D,), reflectance, and recording sensitivity were measured. The results are shown in Table 1.

The binder, nitrocellulose, contains a lot of nitrocellulose. D.
decreases, and the recording sensitivity also deteriorates.

Examples 5 to 11 Recording bodies similar to those in Example 1 were formed by changing the type of triaryl aluminum salt, and the evaluation results are shown in Table 2.

\ \

[Brief explanation of drawings]

FIG. 1 shows a recording/reproducing apparatus used to implement the present invention. 1.・・・Half-body laser 2...Beam splitter 8・・・・・・λ/4 plate 4...Condensing lens 5...Photodiode 6...Recording layer 7... Board 8...Motor Figure 1

Claims (1)

[Scope of Claims] General formula (1) (where R1, R2, Re, R4, R5 and R6 are the same or different hydrogens, an alkyl group, an aralkyl group, a phenyl group, a substituted phenyl group, L An optical information recording medium characterized by having a thin film layer containing a triarylaminium salt represented by the following formula.