JPS62193885A - Optical information-recording medium - Google Patents

Abstract

PURPOSE:To contrive higher sensitivity and stability of an optical information- recording medium used for writing and reproducing information by laser light, by providing a recording layer comprising a specified organic coloring matter. CONSTITUTION:A recording layer is provided which comprises an organic coloring matter of formula I, wherein R1 is a 1-6C alkyl, aralkyl or phenyl, A is formula II or the like, X is an anion such as a perchlorate ion and a fluoroborate ion, Y is a 1-18C alkyl, phenyl, -R4OR5 or the like, Z is a benzene ring added to the benzene ring constituting indole. Since the coloring matter has an alicyclic ring of formula II or the like introduced into a methine chain, it has excellent preservation stability and characteristics of deterioration on reproduction. In addition, the coloring matter has excellent moisture resistance, since the benzene ring as Z is added to the benzene ring constituting indole. Further, the coloring matter has the substituent group Y introduced into indole, and when an alkyl, aralkyl or the like is introduced as Y, moisture resistance and heat resistance are relatively enhanced.

Description

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

[Prior art and problems]

In general, optical disks can store high-density information by forming optically detectable small (for example, about 1 μm) pits in a spiral or circular track shape formed in a thin film recording layer provided on a substrate. To write information on such a disk, a focused laser is scanned over the surface of the laser-sensitive layer, and a focus is formed only on the surface irradiated with the laser beam, and the pits are formed into a spiral or circular track. Formed in the form of. This sensitive layer can absorb laser energy to form optically detectable pits. For example, in the heat mode recording method, the recording layer absorbs laser energy and the irradiated area is locally heated, causing physical changes such as melting, evaporation, or aggregation, resulting in optical differences (e.g. reflectance, etc.) between the recording layer and the non-irradiated area. absorption chambers, etc.) and read them.

As such optical recording media, inorganic materials such as metal thin films 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 methods, suction methods, etc., 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 and high thermal conductivity. It has drawbacks such as high specific heat. In particular, if the reflectance is high, the energy of the laser beam cannot be used effectively, so the optical energy required for recording increases, and a high-output laser 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 it has become possible to select absorbency, with high absorption rate and low heat conduction.
In addition, research proposals have been made on optical memory media using dye thin films as recording layers because of their high productivity and low toxicity. Typical pigments include cyanine pigments (
JP-A-58-112790), anthraquinone pigments (
JP-A-58-224448), naphthoquinone dyes (JP-A-58-224793), and phthalocyanine dyes (JP-A-6O-48396), which can be used alone or in combination with self-oxidizing resins. This is an optical recording medium in which a compound is formed on a substrate by spinner coating, dipping, plasma, vacuum evaporation, or the like. This dye thin film system has the above-mentioned advantages, and in particular, cyanine dyes are structurally capable of having an absorption wavelength in the near infrared region, and also have advantages such as low solubility in solvents and low melting point, so they are often used. It is being considered. On the other hand, it has been said that there are problems with long-term storage and playback stability (stability against readout light), etc. due to light deterioration, instability against heat, and humidity deterioration. Various improvements have been made to address these problems. A proposal has been proposed. Specifically, a protective film is provided on the recording layer (Japanese Patent Application Laid-Open No. 55-22961.57-66541).
), mixing an anti-fading substance based on phosphorus (Japanese Patent Laid-Open No. 59-55795), and adding a metal complex having light absorption in a long wavelength region (Japanese Patent Laid-Open No. 59-215892) have been proposed. However, even these proposals have not sufficiently solved the problem, and problems have arisen in which additives cause a decrease in film formability, reflectance, and absorption.

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, C in the formula is O, S s So e C, X is /
"10rn anion, BF4-, C4O4"", R
(indicates alkyl) However, the cyanine dye represented by the above general formula also has an inherent drawback of lacking film-forming properties and heat-light stability. Regarding film formability, the number of methine chains (n)
It is known that the solubility in bath agents decreases due to an increase in the number of compounds, and that the solubility changes depending on the types of heterocycles at both ends and the types of substituents. 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 provides an optical information recording medium z''hs characterized by having a recording R 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 a phenyl group, (R2; a water film atom or an alkyl group having 1 to 6 carbon atoms), and X is /1,000-chlorate, fluoro? Anion selected from ester, iodide, chloride, bromide, p-toluenesulfonate, Y is an alkyl group having 1 to 18 carbon atoms, phenyl group, -R40R,5, -R4CO
R5, -R4COOR5, group, R5; alkyl group having 1 to 18 carbon atoms or phenyl group), 2 represents a benzene ring added to the benzene ring constituting indole.

By introducing a tetracycle or the like into the methine chain, the organic dye used in the present invention has higher heat resistance and better heat resistance than the cyanine dye composed only of methine chains as disclosed in JP-A-59-85791. It is possible to form a recording layer with improved light resistance and better storage resistance and playback deterioration characteristics. R2 introduced into the cyclo ring and the like is as described above, but particularly when a halogen atom, CL, Br, or an alkyl group is used, R2 preferably has 1 to 3 carbon atoms.

Furthermore, the organic dye used in the present invention can be prepared by adding a benzene ring as 2 to the benzene ring constituting the indole.
94595, in which the benzene ring constituting the indole is unsubstituted or substituted with an alkyl group, has improved hydrophobicity and moisture resistance, which is one of the elements of environmental resistance. Furthermore, since the light fading resistance is improved, reproduction deterioration, which is one of the characteristics of the medium, is improved.

Furthermore, the organic dye used in the present invention has a structure in which the above-mentioned substituent Y is introduced into indole, but if an alkyl group, aralkyl group, etc. are introduced as Y, the moisture resistance and heat resistance are relatively improved; as -R4COR5, -R40R
When a 5,-R4COOR5 group or the like is introduced, solvent solubility and film forming properties are improved.

For this reason, the substituent Y may be appropriately selected depending on the configuration and purpose of the recording medium.

Specific examples of the dye represented by the above general formula include:
Examples include those shown in the following structural formulas (1) to αυ.

A recording layer containing a dye represented by the above general formula can be prepared by dissolving the dye in a solvent such as ethyl acetate, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methylene chloride, alcohol, etc., using a spinner method, dipping method, doctor blade method, etc. It is obtained by forming a thin film on a substrate using a roll coater method or the like. The thinner the recording layer is, the higher the recording sensitivity becomes. However, since the reflectance depends on the film thickness, the thickness is 10 nm to 1000 nm, preferably 30 nm to 1000 nm.
A range of 0 nm to 500 nm is appropriate. In addition, commonly used substrates such as glass, plastic, and metal can be used, but acrylic resin, polycarbonate, polyolefin, polyester, etc. It may also be a liimide film or molded plate.

The recording layer is formed by the method described above. Furthermore, a binder resin is added to the dye at a rate of 1 to 40 times, preferably 3 to 201 times.
By adding i, 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 homopolymers of acrylic, ester, nitrocellulose, ethylene, fluoropylene, carbonate, ethylene terephthalate, epoxy, butyral, vinyl chloride, vinyl acetate, styrene, and copolymers thereof. be able to.

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 layer other dyes to improve heat resistance, moisture resistance, and light resistance. Examples of the dyes used here include cyanine dyes, merocyanine dyes, anthraquinone dyes, triphenylmethane dyes, xanthine dyes, and phthalocyanine dyes.

For example, amine compounds represented by the following general formulas (A) and (B) or dithiolate metal complexes represented by the following general formula (C) are added to prevent deterioration of the optical properties of the recording layer due to light, oxygen, and moisture. It is also possible to do so.

R, however, R,, R2, R4, R5 in formula 1 have 1 or more carbon atoms,
R represents an alkyl group having 1 to 6 carbon atoms.

...... CB) However, R in the formula is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X is an anion such as a perchlorate ion, a fluoroborate ion, a hexafluoroate ion, m is O or an integer of 1 or 2, A is m=o, and 1 is, for example, commercially available IRQ-002゜IRQ-003 (both Nippon Kayaku (Nippon Kayaku)
Co., Ltd.) and others.

...... (C) However, R1-R4 in the formula are an alkyl group or a phenyl group,
X, Y are hydrogen, alkyl group, halogen group, M is Nl e
It shows metals such as Co y Fe HCr.

Such metal complexes include 1, for example PA1001-100.
6 (Both are Mitsui Toatsu Fine Exhibition product names), Nl-
Bis(0-xylene/-4,5-diol)tetra(t-
(dityl) ammonium salts, 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. As the resin, for example, single or copolymers of t[jJ], vinyl acetate, acrylic, ester, nitrocellulose, carcanate, ethylene, glopyrene, butyral, etc. can be used, and if necessary, Depending on the situation, it is possible to contain antioxidants, ultraviolet light absorbers, leveling agents, water repellents, etc. These are formed by a spinner method, a dipping method, or a doctor blade method. Examples of inorganic compounds include sio e sio e
ht2o,.

5n02t MgF2 etc. are used, and the ion beam,
A thin film is formed using an electron beam and the S9 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.

Figure @1 shows the basic structure of an optical information recording medium, with a dye of the general formula on a substrate 1! This is a structure in which a recording layer 2 including a recording layer 2 is provided. Recording and reproduction are performed by condensing Radhe beams into a square having a size of 0.8 to 1.5 μm on the recording layer 2 using three condenser lenses.

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 Figure 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, and 8 is a spindle hole. According to this configuration, the characteristics are 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]

Examples of the present invention will be described in detail below.

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

Example 2 The dye of structural formula (6) described above was dissolved in methylene chloride at a solubility value of 1.
0 et 'JN Confucianism 4a, lyM b
-2u-/-)--It was coated on a glass substrate with a thickness of 1.2 m using a coater and dried to form a recording layer with a thickness of 70 nm to produce a recording medium.

Example 3 The above-mentioned dye of structural formula (8) was dissolved in methyl ethyl ketone to obtain a 21 g solution, which was then applied onto a glass substrate with a thickness of 1.21 mm 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 4 The dye of structural formula (2) described above was dissolved in methylene chloride,
After making a 2-inch solution, this was coated with a spinner coater to a thickness of 1.
A recording layer was formed with a thickness of 80 nm by coating and drying on the glass substrate of 2-, and a recording medium was manufactured. Manufactured by Mitsubishi Rayon Co., Ltd.: Dianal BR-
60) was added at 10% by weight and dissolved in methyl ethyl ketone to obtain a 3-width solution. This solution was applied onto a 1.2-thick glass substrate using a spinner coater and dried to a thickness of 90 nm. (9) manufacturing a recording medium by forming a recording layer;

Example 6 The dye having the structural formula αQ described above and the infrared absorber (trade name: IRG-oo:3, manufactured by Nippon Kayaku Co., Ltd.) were mixed in a weight ratio of 3:1.
This was mixed with methylene chloride to make a 2-inch volume solution, and this solution was coated with a spinner coater to a thickness of 1.
Coated on a 2W glass substrate and dried to a thickness of 70 nm.
A recording medium was manufactured by forming a recording layer.

Example 7 The dye having the structural formula (1) described above and the dye having the following structural formula αQ were mixed at a weight ratio of 2:1, dissolved in the same manner as in Example 1, coated on a substrate, and dried. A recording layer with a thickness of 70 nm was formed in this manner, and a recording medium was manufactured.

Example 8 Structural formula (8
) After forming a recording layer with a thickness of 60 nm consisting of a dye of
A recording medium was produced by forming a reflective protective layer with a thickness of 30 nm by vacuum heating vapor deposition under the conditions of After dissolving to make a two-width solution, this solution was coated with a spinner coater to a thickness of 1.
21 on a glass substrate and dried to a thickness of 70 nm.
A recording layer was formed to produce a recording medium.

Comparative Example 2 A dye having the following structural formula (n) was dissolved in the same manner as in Comparative Example 1, coated on a glass substrate, and dried to form a recording layer with a thickness of 70 nm to produce a recording medium.

Comparative Example 3 A liquid having the following structural formula (III) was dissolved in the same manner as in Comparative Example 1, applied onto a glass substrate, and dried to a thickness of 70 nm.
A recording layer was formed to produce a recording medium.

Comparative Example 4 A dye having the following structural formula (IV) was dissolved in the same manner as in Comparative Example 1, spread on a glass substrate, and dried to form a recording layer with a thickness of 70 nm to produce a recording medium.

For the recording layers of the recording media of Examples 1 to 8 and Comparative Examples 1 to 4, semiconductor laser light with a wavelength of 830 nm was focused onto a spot with a diameter of 1.2 μm so that the medium surface output was mW. , this focused laser beam was moved from the substrate side of each recording medium at a moving speed of 9 g/aec under the condition of I MH
Write z signal and reproduce output 0.4mW with the same radar light
The recording sensitivity (recording energy threshold) and the C2 side of the reproduced signal were measured. One more example 1-8
The recording media of Comparative Examples 1 to 4 were left for 150 hours at 50 DEG C. in a 95% atmosphere, and a heat-humidity test was conducted to measure the absorbance decrease rate and reflectance decrease rate before and after the exposure. A light emission test was conducted in which each recording medium was irradiated with 501 M soow tungsten light in an atmosphere of 604°C at 25° C. for 100 hours, and the absorbance reduction rate and reflectance reduction rate before and after irradiation with the tungsten light were measured. These results are shown 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... Rade light, 4
... Intermediate layer, 5... Protective layer, 6... Spacer. Applicant's representative Patent attorney Atsushi Tsuboi Figure 2 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 with 1 to 6 carbon atoms, an aralkyl group, or a phenyl group, and A is ▲ There are ▲ mathematical formulas, chemical formulas, tables, etc. , tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are 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.▼,▲Mathematical formulas, chemical formulas,
There are tables etc. ▼ (R_2; hydrogen atom or alkyl group having 1 to 6 carbon atoms), X is an anion selected from perchlorate, fluoroborate, iodide, chloride, bromide, p-toluenesulfonate, Y is , C1-C18 alkyl group, phenyl group, -R_4OR_5, -R_4C
OR_5, -R_4COOR_5, ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (R_4: alkyl group with 1 to 20 carbon atoms, R_5: alkyl group with 1 to 18 carbon atoms or phenyl group), Z is benzene constituting indole A benzene ring added to the ring is shown.