JPS62193888A - 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 semiconductor laser, 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, Y is a 1-18C alkyl, phenyl, -R4OR5, -R4-COR5, -R4 COOR5 or the like, and Z is 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 or aralkyl 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 laser, 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. To write information on such a disk, a focused laser beam is scanned over the surface of the laser-sensitive layer, pits are formed only on the surface irradiated with the laser beam, and the pits are shaped like a spiral or circular track. form in form. This sensitive layer can absorb Rede energy to form optically detectable pits. For example, in the heat mode recording method, the recording layer absorbs Radhe energy, and the irradiated area is locally heated, causing physical changes such as melting, evaporation, or aggregation, resulting in optical differences (e.g., reflectance) between the recording layer and the non-irradiated area. , absorption rate, 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 chalcogenide-based amorphous glass films have been proposed.゛These have the advantage that thin films can be obtained using vapor deposition or sputtering 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, high thermal conductivity, and low specific heat It also has disadvantages such as being large. In particular, if the reflectance is high, the energy of the Raded light cannot be used effectively, so the optical energy required for recording is large, and a high-output Raded light source is required. the result,
The drawback is that the recording device is large and expensive. Furthermore, thin films of tellurium, bismuth, selenium, etc. have the disadvantage of being toxic. For these reasons, in recent years, research has begun on optical memory media that use dye thin films as recording layers because they allow selection of absorption properties, high absorption rates, low thermal conductivity, good productivity, and low toxicity. Suggestions are being made. Typical dyes include cyanine dyes (JP-A-58-112790), anthraquinone-based dyes (JP-A-58-224448), and naphthoquinone-based dyes (/?i).
[58-224793) and phthalocyanine dyes (JP-A-60-48396), etc., and compounds consisting of these alone or in combination with self-oxidizing resin can be applied by spinner coating, dipping, plasma, vacuum deposition, etc. In other words, it is an optical recording medium formed on a substrate. This dye thin film system has the above-mentioned advantages; in particular, the cyanine dye can structurally have an absorption wavelength in the near-infrared region, and also has advantages such as bath solubility in solvents and a low melting point. For this reason, many studies have been conducted. On the other hand, it has been said that there are problems with light deterioration, instability with heat, humidity deterioration, etc., long-term storage stability, playback stability (stability against readout light), etc., and there are various problems regarding these problems. Improvement plans have been proposed. Specifically, a protective film is provided on the recording layer (JP-A-55-22961.57-66541).
, mixing a substance that prevents discoloration due to oxygen (Japanese Patent Application Laid-open No. 1983
-55795), adding a metal complex having light absorption in a long wavelength region (Japanese Patent Laid-Open No. 59-215892), etc. have been proposed. 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, coating type recording media using cyanine dyes represented by the following general formula are attracting attention in terms of recording density and reflectivity.

RR [However, Ait, o, S, Sa, C,
X represents a halogen anion, BF-1C1O4-, and R represents an alkyl.] However, the cyanine dye represented by the above general formula also has the essential problem of lacking film-forming properties and heat-light stability. Regarding film formability, the number of methine chains (n)
It is known that solvent solubility decreases due to an increase in , and that solubility changes depending on the type of heterocycle at both ends and the type of substituent. Regarding heat and light stability, as the number of methine chains increases, it becomes more unstable to heat and light, and oxidative deterioration is more likely to occur, and the stability to heat and light differs depending on the type of heterocycle. It has been known.

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 vb 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 a phenyl group, a halodane atom, an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.
6 alkyl group)], Xid, an anion selected from verchlorate, fluoroborate, iodide, chloride, bromide, p-toluenesulfonate, Y is an alkyl group having 1 to 18 carbon atoms, phenyl group, -ROR -RCOR, -R
4COOR5, group, R5; alkyl group having 1 to 18 carbon atoms or phenyl group), 2 represents a benzene ring added to the benzene ring constituting the indole.

The organic dye used in the present invention has a methine chain, and therefore has higher heat resistance and light resistance than a cyanine dye composed only of a methine chain, such as the one disclosed in JP-A-59-85791. It is possible to form a recording layer with improved storage resistance and playback deterioration characteristics. The R2 introduced into the cyclonef etc. is as described above, but when a helogne atom is used for bamboo, when C1, Br or an alkyl group is used, one with 1 to 3 carbon atoms is introduced. preferable.

Further, the organic dye used in the present invention can be prepared by adding a benzene ring as benzene ff1KZ constituting indole, and the method disclosed in JP-A-59-150795 and JP-A-58
-194595, in which the benzene ring constituting the indole is unsubstituted or substituted with an alkyl group, has increased hydrophobicity and moisture resistance, which is one of the elements of environmental resistance. You can improve your sexuality. Furthermore, since the color 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 when an alkyl group or an aralkyl group is introduced as Y, moisture resistance and heat resistance are relatively improved. Chi R4C0R5, -R40R5
, -R, COOR5 improves solvent solubility and film formability. 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 structural formulas (1) to o4 below.

^
−＼−ω
! dumb
Q
■♂
0da Hayabusa 6 Dan: 4! 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 isobutyl ketone, methylene chloride, or alcohol, and applying the spinner method, dipping method, or doctor method. blade method,
It can be obtained by forming a thin film on a substrate using a roll coater method or the like. The thinner the thickness of this recording layer, the higher the recording sensitivity, but since the reflectance depends on the film thickness,
nm ~ 1000 nm, preferably 3゜nm ~ 50 nm
A range of 0 nm is appropriate.

In addition, commonly used substrates such as glass, plastic, and metal can be used, but acrylic resin, polycarbonate, polyolefin, polyester,
? It may also be a liimide film or molded plate.

The recording layer is formed by the method described above. Furthermore, by adding 1 to 40% by weight, preferably 3 to 20% by weight, of a binder resin to the dye, it is possible to form a film, and the film formability, heat resistance, and moisture resistance can be improved. Examples of the binder resin used here include acrylic, ester, nitrocellulose, ethylene, fluoropylene, and carbon
Examples thereof include homopolymers such as l-t, ethylene terephthalate, epoxy, butyral, vinyl chloride, vinyl acetate, and styrene, and copolymers thereof.

In addition, by mixing other dyes in place of the binder resin or creating a multilayer structure in which dye layers are stacked, it is possible to improve film formability, heat resistance, moisture resistance, and light resistance. It is possible to obtain an optical information recording medium with excellent density, 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 dyes used here include cyanine dyes, merocyanine dyes, anthraquinone dyes, triphenylmethane dyes, xanthine dyes, 7
Examples include talocyanine pigments.

For example, amine compounds represented by the following general formulas (4) 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.

However, R1, R2, R4, and R5 in the formula have 1 or more carbon atoms,
R represents an alkyl group having 1 to 6 carbon atoms.

...(B) 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 persalt acid ion, a fluoroborate ion, a hexafluoroate ion, etc., and m is an O or an integer of 1 or 2, A is the above-mentioned m=O+ 1. Examples of the examples include commercially available IRQ-002 and IRQ-003 (both split product names manufactured 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, 710 Dan group, M is N1
+ Co I Fe + Cr and other metals. Examples of such metal complexes include PA100I-1
006 (both Mitsui Toatsu Fine Co., Ltd. dehiscence product names),
Ni-bis(0-xylene-4,5-nol)tetra(
1-butyl) 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. Examples of the resin include vinyl chloride, vinyl acetate, acrylic, ester, nitrocellulose, carbonate, xyfoxy,
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 8102.810, At20
3°SnO□, MgF2, etc. are used, and a thin film is formed by an ion beam, an electron beam, or a sputtering 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 1. Recording and reproduction are performed by condensing the Radhe beam 3 onto the recording layer 2 using a condensing lens into a spot having a size of 0.8 to 1.5 tails.

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 plate 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 gear, and f and 8 are spindle holes. According to such a configuration, the characteristics are good;
Furthermore, it has the advantage of suppressing the influence of stains and dirt on the recording layer 2.

Furthermore, in the configurations of FIGS. 1 to 3 described above:
, 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 (2) was dissolved in methyl ethyl ketone to form a two-layer solution, which was coated on a glass substrate with a thickness of 1.2 mm using a spinner coater and dried to a thickness of 70 mm.
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,
After making a 2% solution, it was coated with a spinner coater to a thickness of 1.
A recording medium was manufactured by coating and drying on a glass substrate of Nikaku to form a recording layer with a thickness of 75 nm.

Example 3 The dye 1 was dissolved in methylene chloride to the above structural formula to form 2.
% solution, this was coated with a spinner coater to a thickness of 1.2%.
A recording medium was manufactured by coating and drying on the glass substrate (2) to form a recording layer with a thickness of 70 nm.

Example 4 The dye having the structural formula 0 described above was dissolved in methylene chloride, and 2
After making it into a solution, it was coated with a spinner coater to a thickness of 1.2 mm.
A recording layer with an If of 75 nm was formed by coating and drying on a cod glass substrate to produce a recording medium.

Example 5 An acrylic resin (manufactured by Mitsubishi Rayon Co., Ltd.: Dianal BR-) was added to the dye of structural formula (6) as a binder resin.
60) was added in an amount of 10% by weight, and this was dissolved in methyl ethyl ketone to obtain a 3-layer solution. This solution was applied onto a glass substrate with a thickness of 1.2 cm using a spinner coater, and dried to a thickness of 80 am. A recording medium was manufactured by forming a recording layer.

Example 6 The dye of structural formula (3) described above and an infrared absorber (product name: IRQ-003, manufactured by Nippon Kayaku Co., Ltd.) were mixed at a weight ratio of 3:1, and this was dissolved in methyl ethyl ketone. After making a 2% solution, this solution was applied onto a 1.2 nm thick glass substrate using a spinner coater and dried to a 70 nm thick solution.
A recording medium was manufactured by forming a recording layer of m.

Example 7 The dye of structural formula (2) described above and the dye of structural formula 〇9 below were mixed at a ML ratio of 2:1, dissolved in the same manner as in Example 1, and applied on a substrate. A recording layer having a thickness of 75 nm was formed by drying, and a recording medium was manufactured.

Example 8 The structural formula (2
) After forming a recording layer with a thickness of 60 nm, an aluminum naphthalocyanine represented by the following structural formula Q was formed on the recording layer at a vacuum degree of 1. OX 1O-5Tsrr
A reflective protective layer with a thickness of 30 nm was formed by vacuum heating evaporation under the following conditions to produce a recording medium.

Comparative Example 1 A dye represented by the following structural formula (1) was dissolved in methylene chloride to make a 2-layer solution, and this bath solution was coated with a spinner coater to a thickness of 1.5 mm.
Coated on a 2wm glass substrate and dried to a thickness of 80mm.
A recording layer with a thickness of 100 nm was formed to produce a recording medium.

Comparative Example 2 A dye having the following structural formula (II) 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.

CH20C2H5CH20C2H5 Comparative Example 3 A dye having the following structural formula (Ill) 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 °Cm to produce a recording medium. .

Comparative Example 4 A dye having the following structural formula (5)) was dissolved in a bath 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°C to produce a recording medium. did.

For the recording layers of the recording media of Examples 1 to 8 and Comparative Examples 1 to 4, semiconductor radar light with a wavelength of 830 nm was focused on a spot with a diameter of 1.2 μm so that the medium surface output cuff was mW. This condensed radar light is transferred from the substrate side of each recording medium at a moving speed of 9rrV/sec.
Writes a Hz signal and reproduces output of 0.4m using the same radar light.
Reproduction was performed using W, and the recording sensitivity (recording energy threshold) and C/SJ value of the reproduced signal were measured. In addition, this example 1
The recording media of ~8 and Comparative Examples 1 to 4 were left in a 95% atmosphere at 50° C. for 150 hours, and the absorbance decrease rate before and after being left,
A heat and humidity resistance test was conducted to measure the rate of decrease in reflectance. Each recording medium was irradiated with 500W tungsten light for 50 hours in a 60% atmosphere at 25°C, and a light emission test was conducted to measure the absorbance reduction rate and reflectance reduction rate 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 agent 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.▼, ▲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_2 is a hydrogen atom, a halogen atom, the number of carbon atoms 1 to 6 alkyl groups, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (Ph; phenyl group), ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼, (R_3; Alkyl groups with 1 to 6 carbon atoms)], is an anion selected from perchlorate, fluoroborate, iodide, chloride, bromide, p-toluenesulfonate, Y is an alkyl group having 1 to 18 carbon atoms,
Phenyl group, -R_4OR_5, -R_4COR_5,
-R_4COOR_5, ▲Mathematical formulas, chemical formulas, tables, etc.▼(R_4; Alkyl group with 1 to 20 carbon atoms, R_5;
an alkyl group having 1 to 18 carbon atoms or a phenyl group), Z represents a benzene ring added to the benzene ring constituting indole.