JPS62207685A - Optical information-recoding medium - Google Patents

Abstract

PURPOSE:To obtain an optical information-recording medium having high reflectance and recording sensitivity, ensuring stable writing and reproduction of optical signals, having high stability and free of environmental pollution problems, by providing a recording layer comprising a specified organic coloring matter. CONSTITUTION:A recording layer comprising a coloring matter of formula I can be obtained by dissolving the coloring matter in a solvent such as ethyl acetate, toluene and an alcohol, and applying the resultant solution to a base by a spring method, a dipping method or the like to provide a thin film of the base. In formula I, R1 is a 1-6C alkyl, aralkyl or phenyl, R2 is 1-8C alkyl, aralkyl, allyl or phenyl, A is formula II, formula III (wherein R3 is hydrogen or a 1-6C alkyl) or the like, X is an anion selected from perchlorate ion, fluoroborate ion and the like, Y is a 1-18C alkyl, -R4OH or -R4COOH, and m is an integer of 1 or 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical memory medium on which writing, reproduction and recording are performed using a radar, particularly a semiconductor radar.

[Prior art and problems]

In general, optical disks can store high-density information using optically detectable small (for example, about 1 μm) pits formed in a thin film recording layer provided on a substrate in the form of spiral or circular tracks. In order to write information on such a disk, a laser beam focused on the surface of the radar sensitive layer is scanned, pits are formed only on the surface irradiated with the radar beam, and the pits are formed into a spiral or circular track. This sensitive layer absorbs Rade energy and can form optically detectable pits.For example, in the heat mode recording method, the recording layer absorbs Rade energy and the irradiated area is localized. It is detected by heating and causing physical changes such as melting, evaporation, or aggregation, and creating an optical difference (for example, reflectance, absorption rate, etc.) between it and the non-irradiated area, and then reading the difference.

As such optical recording media, inorganic materials such as metal thin films 4 such as aluminum vapor-deposited films, bismuth thin films, tellurium-based thin films, and chalcoglide-based amorphous glass films have been proposed.

These have the advantage that thin films can be obtained by vapor deposition, sputtering, and lithography methods, and semiconductor radars can be used because they absorb light even in the near-infrared region, but on the other hand, they have high reflectance. It has drawbacks such as high thermal conductivity and high specific heat. In particular, if the reflectance is high, the energy of the Raded light cannot be used effectively, so the optical energy required for recording increases, and a high-output Raded light source is required.

As a result, the disadvantage is that the recording apparatus becomes large and expensive. Furthermore, thin films of tellurium, bismuth, selenium, etc. have the disadvantage of being toxic.

For this reason, in recent years, research has been carried out on optical memory media using dye thin films as recording layers because of the ability to select absorption properties, high absorption rates, low thermal conductivity, good productivity, and low toxicity. Suggestions are being made. Typical dyes include cyanine dyes (Japanese Patent Application Laid-Open No. 11279/1983)
0), anthraquinone dye (JP-A-58-22444
8), naphthoquinone dyes (JP-A-58-22479)
3) and 7 talocyanine pigments (JP-A-6O-4839
6), etc., and compounds consisting of these alone or in combination with self-oxidizing resin can be applied using a spinner, dipping method,
This is an optical recording medium formed on a substrate by a plasma method, a vacuum evaporation method, or the like. This dye thin film system has the above advantages,
In particular, cyanine dyes have been studied extensively because they are structurally capable of having an absorption wavelength in the near infrared region and have advantages such as solubility in solvents and low melting points. On the other hand, it has been said that there are problems with long-term storage, playback stability (stability against readout light), etc. due to photodeterioration, instability with heat, and humidity deterioration. Improvement proposals have been proposed. Specifically, a protective film is provided on the recording layer (Japanese Patent Laid-Open No. 55-2
2961.57-66541).

Mixing a substance that prevents fading due to oxygen (% 1986-
55795) and the addition of a metal complex having light absorption in a long wavelength region (Japanese Patent Laid-Open No. 59-215892). However, these proposals do not sufficiently solve the problem, and furthermore, problems arise in that the additives cause a decrease in film formability, reflectance, and absorbance.

For these reasons, a coating type recording medium using a cyanine dye represented by the following general formula is attracting attention from the viewpoint of recording density and reflectivity.

[However, in formula 1, A is O, S, Ss, C, It has an essential problem of lacking film properties and thermal and light stability. Regarding film formability, the number of methine chains (,)
It is known that the solubility in solvents decreases as the number increases, and that the solubility changes depending on the type of double-stranded ring at both ends and the type of substituent. Regarding thermophotostability, it is known that as the number of methine chains increases, it becomes more unstable to heat and light, and oxidative degradation is more likely to occur, and that the stability to heat and light differs depending on the type of heterocycle. It is being

The present invention was developed in view of the above circumstances, and has high reflectance and high recording sensitivity, enables stable writing and reproduction of optical signals, and is capable of handling light and sunlight during reproduction.
The present invention aims to provide a pollution-free optical information recording medium that is highly stable against humidity.

[Means and effects for solving the problems] The present invention is an optical information recording medium characterized by having a recording layer containing an organic dye represented by the following general formula.

However, R1 in the formula is an alkyl group having 1 to 6 carbon atoms, an aralkyl group, or phenyl, and R2 is an alkyl group having 1 to 18 carbon atoms, an aralkyl group,
Allyl group or phenyl group (R5; hydrogen atom or alkyl group having 1 to 6 carbon atoms).

X is an anion selected from nono-chlorate, 7/I/ologolate, iodide, chloride, bromide, p-toluenesulfonate, and Y is an anion having 1 to 1 carbon atoms.
8 alkyl group, -Ft4ot(-R4COR5(,
-R40R5, -R4COR5, -R4COOR5, (
R4; Alkyl group having 1 to 20 carbon atoms, R5; C1 to 20
18 alkyl group, phenyl group), m represents an integer of 1 or 2.

The organic dye used in the present invention can be produced by introducing a cyclo ring represented by into the methine chain.
Compared to organic dyes composed only of methine chains such as those disclosed in No. 791, it has superior durability and light resistance, and environmental resistance.
A recording layer with high reproduction deterioration characteristics can be formed. R3 in the cyclo ring and the like is as described above, but chlorine, bromine, or an alkyl group having 1 to 3 carbon atoms is particularly preferable.

However, by introducing a cyclo ring or the like into the methine chain, the solubility of the dye in the solvent is slightly lowered, so the solvent is limited and it becomes difficult to form a uniform film.

Therefore, in the organic dye of the present invention, the light resistance, chemical stability, and maximum absorption wavelength of the dye can be controlled by introducing one or two -COOR2 substituents into the benzene ring constituting the indole as described above. In addition, solvent solubility and film formability can be significantly improved. In addition, the ester group
The preferred position for substitution on the Zene ring is the 5th position as it is easiest to substitute, but both the 4th and 6th positions are also possible. However, it is desirable to introduce a field that improves the thermal stability and chemical stability, and when considering film formability and solvent solubility, -R4COOf(
.

-R40R5, -R4COR5, -R4COR5 are desirable.

As mentioned above, the organic dyes having the structure in which the above-mentioned substituents are introduced are disclosed in Japanese Patent Application Laid-open Nos. 59-150795 and 58-194595.
light and chemical stability, solvent solubility, and
The optical information recording medium has excellent film formation properties, and as a result, by forming a recording layer containing this dye, the noise component of the reproduced signal waveform due to poor film formation is reduced, and the environmental resistance and reproduction deterioration characteristics are improved. Obtainable.

Specific examples of the dye represented by the above general formula include:
Examples include those shown in Structural Formulas (1) to α1 below.

-〇
cry
lotto
ω[F]
A recording layer containing a dye represented by the above general formula is:

The dye is dissolved in a solvent such as ethyl acetate, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methylene chloride, chloroform, dichloroethane, tetrahydrofuran, alcohol, etc., and then applied using a spinner method, a 7-inch method, a ping method, a doctor blade method, or a roll coater method. It can be obtained by forming a thin film on a substrate, etc. The thinner the recording layer is, the higher the recording sensitivity becomes. , preferably in the range of 30 nm to 500 nm.As the substrate, polyester, acrylic resin, polycarbonate resin, polyolefin resin,
Glass plates and films made of phenolic resin, epoxy resin, tetraamide resin, polyimide resin, etc.

Alternatively, glass, metals, etc. can be used.

The recording layer is formed by the method described above. Furthermore, binder resin is added to the dye by 1 to 40 times + [f'16, preferably 3 to 40 times]
By adding 20% by weight, it is possible to form a film, and film formability, heat resistance, and moisture resistance can be improved.

Examples of the binder resin used here include resins such as acrylic, ester, nitrocellulose, ethylene, propylene, carzenate, ethylene terephthalate, urethane, polyethylene, butyral, vinyl chloride, vinyl acetate, and styrene. , and can also be composited by copolymers of these.

In addition, by mixing other dyes in place of the binder resin or creating a multilayer structure in which dye layers are stacked, film formability, heat resistance, moisture resistance, and light resistance can be improved, resulting in higher density. Therefore, it is possible to obtain an optical information recording medium with high sensitivity and excellent durability without reproduction deterioration. In this case, it is also possible to add other dyes to improve heat resistance, moisture resistance, and light resistance. Examples of the dyes used here include cyanine dyes, merocyanine dyes, anthraquinone color X, iJ phenylmethane dyes, xanthine dyes, and phthalocyanine dyes.

Furthermore, for example, an amine compound represented by the following general formula (A) p (B) or a notothiolate metal complex represented by the following general formula C) is added to prevent deterioration of the optical properties of the recording layer due to light, oxygen, and moisture. It is also possible to prevent this.

-6 alkyl group, R5 is -0-C-R, -0-R.

Here, R represents an alkyl group having 1 to 6 carbon atoms.

However, in the formula, R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X is an anion such as perchlorate ion, fluoroborate ion, hexafluoroate ion, etc., and m is O or an integer of 1.2. , A is the above m=0.1, for example, commercially available I
Examples include RQ-002 and IRQ-003 (both product names developed by Nippon Kayaku Co., Ltd.).

However, R1-R4 in the formula is an alkyl group or a phenyl group,
X, Y are hydrogen, alkyl group, heron group, M is Nl,
This indicates metals such as Co, Fe, and Cr. Examples of such metal complexes include PA 1001-1
006 (All product names developed by Mitsui Toatsu Fine Co., Ltd.)
, N1-bis(0-xylene-4,5diol)tetra(t-butyl)ammonium salt, etc.

In addition to the recording layer containing the dye of the above general formula, an intermediate layer and a protective layer may be provided as necessary. The intermediate layer is provided for the purpose of improving adhesion and protecting from oxygen and moisture, and is mainly formed from a resin or an inorganic compound. Examples of the resin include tif vinyl bivinylate, acrylic, ester, nitrocellulose, carbonate, epoxy,
Single or copolymers of ethylene, propylene, butyral, etc. can be used, and if necessary, antioxidants, ultraviolet light absorbers, leveling agents, water repellents, etc. can be included. These are formed by a spinner method, a dipping method, or a doctor blade method. Examples of inorganic compounds include 8102. SiO, At203
゜SnO□, MgF2, etc. are used, and ion beam,
A thin film is formed using an electron beam and a four-step method.

The protective layer also has the same structure as the intermediate layer, and is used to protect the recording layer from light, oxygen, and moisture, and from scratches, dust, and the like.

Next, a configuration example of the optical information recording medium of the present invention will be described with reference to the drawings.

FIG. 1 shows the basic structure of an optical information recording medium, in which a recording layer 2 containing a general formula dye is provided on a substrate l. Recording and reproduction are performed by condensing the radar beam 3 onto the recording layer 2 by a condensing lens onto a strip having a size of 8 to 1.5 .mu.m.

The radar light 3 for recording and reproduction may be irradiated from the recording layer 2, but when the substrate 1 is made of a transparent material, it is generally better to irradiate from the substrate 1 side to reduce the influence of dirt and dust.

FIG. 2 shows a structure in which an intermediate layer 4 is provided between the substrate 1 and the recording layer 2, and a protective layer 5 is provided on the recording layer 2.

In FIG. 3, two media having the same configuration are arranged with a spacer 6 in between so that the recording layers 2 face each other.

In addition, 7 in FIG. 3 is an air gap f, and 8 is a spindle hole. According to such a configuration, 1% of people are sexually good;
Furthermore, it has the advantage that the influence of dirt and dust on the recording layer 2 can be suppressed.

Furthermore, in the configurations of FIGS. 1 to 3 described above, A/,
, Ag, or other reflective films may be provided between the substrate and the recording layer.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail.

Example 1 The above-mentioned dye of structural formula (1) was dissolved in methyl ethyl ketone to form a 2% solution, which was applied onto a 1.2 g thick glass substrate using a spinner coater and dried to a thickness of 75 mm.
A recording medium was manufactured by forming a recording layer with a thickness of 100 nm.

Example 2 The dye of structural formula (2) described above was dissolved in methylene chloride,
After making a 2% solution, it was coated with a spinner coater to a thickness of 1.
Coated on a 2 m glass substrate and dried to a thickness of 70 nm.
A recording medium was manufactured by forming a recording layer.

Example 3 The above-mentioned dye of structural formula (4) was dissolved in methylene chloride to form a 2-layer solution, which was then coated with a spinner coater to a thickness of 1.5 mm.
A recording medium was manufactured by coating and drying on a glass substrate No. 2-2 to form a recording layer having a thickness of 70 nm.

Example 4 The dye of structural formula (9) described above was dissolved in methylene chloride,
After making a 2-inch solution, it was coated with a spinner coater to a thickness of L2.
A recording layer with a thickness of 75 nm was formed by coating and drying on a glass substrate of 75 nm to produce a recording medium.

Example 5 An acrylic resin (manufactured by Mitsubishi Rayon Co., Ltd.: Dianal BR-
60) was added in an amount of 10% by weight, and this was dissolved in methyl ethyl ketone to make a 3-chi solution. This solution was coated on a glass substrate with a thickness of 1.2 using a spinner coater, and dried to form a record with a thickness of 80 nm. A recording medium was manufactured by forming layers.

Example 6 The dye of structural formula (5) described above and an infrared absorber (trade name: IRG-003, manufactured by Nippon Kayaku Co., Ltd.) were mixed at a weight ratio of 3=1, and this was dissolved in methyl ethyl ketone. This solution was coated on a glass substrate with a thickness of 1.2 nm using a spinner coater, and dried to a thickness of 70 nm.
A recording medium was manufactured by forming an RO recording layer.

Example 7 The dye of the above structural formula (8) and the dye of the following structural formula Dry thickness 70 nrn
A recording layer was formed to produce a recording medium.

Example 8 Structural formula (6
) After forming a recording layer with a thickness of 60 nm consisting of a dye of
A reflective protective layer with a thickness of 30 mm was formed by vacuum heating evaporation under the following conditions to produce a recording medium.

Comparative Example 1 A dye having the following structural formula (1) was dissolved in methylene chloride to form a 2-layer solution, and this solution was coated with a spinner coater to a thickness of 1.5 mm.
2. Coated on a glass substrate and dried to a thickness of 80 nm.
A recording layer was formed to produce a recording medium.

Comparative Example 2 A recording medium was manufactured by dissolving a dye having the following structural formula in the same manner as in Comparative Example 1, coating it on a glass substrate, and drying it to form a recording layer with a thickness of 70 nm.

CH2QC2H5C■20C2H3 Comparative Example 3 A dye having the following structural formula (to) was dissolved in the same manner as in Comparative Example 1, coated on a glass substrate, dried to form a recording layer with a thickness of 70 nn%, and a recording medium Manufactured.

Comparative Example 4 A dye having the following structural formula was dissolved in the same manner as in Comparative Example 1,
A recording layer with a thickness of 70 nm was formed by coating and drying on a glass substrate to produce a recording medium.

For the recording layers of the recording media of Examples 1 to 8 and Comparative Examples 1 to 4, a diameter of 1.21 km was measured so that semiconductor radar light with a wavelength of 830 nm would be emitted from the surface of the medium at mW. , and reproduced the focused radar light from the substrate side of each recording medium at a main output of 0.4 mW to determine the recording sensitivity (recording energy threshold) and the C/N value of the reproduced signal. It was measured. In addition, the recording media of Examples 1 to 8 and Comparative Examples 1 to 4 were heated at 50° C. and 95° C. for 150° C.
A heat and humidity resistance test was conducted in which the sample was allowed to stand for a period of time and the rate of decrease in absorbance and rate of decrease in reflectance were measured before and after being left. Furthermore, 500W tungsten light was applied to each recording medium at 25°C in a 60% atmosphere.
A light emission test was conducted in which the tungsten light was irradiated for 100 hours and the absorbance reduction rate and reflectance reduction rate were measured before and after irradiation with tungsten light. These results are shown in the table below.

〔Effect of the invention〕

As detailed above, the present invention has high reflectance and high recording sensitivity, enables stable writing and reproduction of optical signals, and has low stability against reproduction light, sunlight, and humidity. A highly pollution-free optical information recording medium can be provided.

[Brief explanation of drawings]

1 to 3 are schematic diagrams showing optical information recording media of the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Recording layer, 3... Laser light, 4
... Intermediate layer, 5... Protective layer, 6... Spacer. Applicant's representative Patent attorney Atsushi Tsuboi? l'm2
Figure 3

Claims (1)

[Scope of Claims] An optical information recording medium characterized by having a recording layer containing an organic dye represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, R_1 in the formula is an alkyl group having 1 to 6 carbon atoms, an aralkyl group, or a phenyl group, and R_2 is an alkyl group having 1 to 18 carbon atoms, an aralkyl group, an allyl group, or Phenyl group, A, has ▲ mathematical formulas, chemical formulas, tables, etc.▼, ▲ has mathematical formulas, chemical formulas, tables, etc.▼, ▲ has mathematical formulas, chemical formulas, tables, etc.▼, ▲ has mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_3; hydrogen atom or alkyl group with 1 to 6 carbon atoms), X is perchlorate, fluoroborate, iodide, chloride , bromide, p-toluenesulfonate, Y is an alkyl group having 1 to 18 carbon atoms, -R_4OH, -R_4COOH, -R_4
OR_5, -R_4COR_5, -R_4COOR_5
, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_4: Alkyl group with 1 to 20 carbon atoms, R_5: 1 carbon number ~18 alkyl group, phenyl group), m is 1 or 2
An integer of , denotes.