JPS62103192A - Optical information-recording medium - Google Patents

Abstract

PURPOSE:To provide an optical information-recording medium having high reflectance and recording sensitivity, capable of stably writing and reproducing optical signals, having high stability to light, sunlight and moisture at reproduction time and not generating environmental pollutions, by providing a recording layer comprising a specified organic coloring matter. CONSTITUTION:An organic coloring matter of formula I is incorporated in a recording layer. In formula I, each of R1 and R2 is hydrogen, a halogen, an alkyl or formula II (wherein ph is phenyl), R3 is a 1-6C alkyl, aralkyl or phenyl, Y is -R4SOC3<-> (wherein R4 is a 1-20C alkyl or aralkyl), Y' is -R4SO3Na or -R4SO3NH(R5)3 (wherein R4 is a 1-20C alkyl or aralkyl and R5 is a 1-18C alkyl), and Z is a benzene ring to be added to the benzene ring constituting indole. By this, a recording layer having excellent preservation stability and reproduction deterioration characteristics can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to writing using a radar, particularly a semiconductor radar,
The present invention relates to an optical memory medium on which playback and recording are performed.

[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 Radical beam is scanned over the surface of the Radical sensitive layer, pits are formed only on the surface irradiated with the Radical beam, and these pits are formed into spiral or circular tracks. 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 (ex, reflection, etc.) between the recording layer and the non-irradiated area. absorption rate, absorption rate, etc.).

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 by evaporation methods, suction methods, etc., and semiconductor radars can be used because they have light absorption even in the near-infrared region, but on the other hand, they have high reflectance, high thermal conductivity, and low specific heat. It has the disadvantage of 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 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 these reasons, research proposals have recently been made on optical memory media that use dye thin films as recording layers because they allow selection of absorption properties, have high absorption rates, low heat conduction, good productivity, and low toxicity. It is coming. Typical dyes include cyanine dyes (JP 58-112790), anthraquinone dyes (JP 58-224448), naphthoquinone dyes (JP 58-224793), and phthalocyanine dyes (JP 58-224793). 48396), etc., and is an optical recording medium in which a compound consisting of these alone or in combination with a self-oxidizing resin is formed on a substrate by a spinner coating dipping method, a plasma method, a vacuum evaporation method, 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 photodeterioration, instability against heat, and humidity deterioration. Improvement proposals have been proposed. Specifically, a protective film is provided on the recording layer (Japanese Patent Application Laid-Open No. 55-22961.57-6).
6541), mixing an oxygen-induced discoloration prevention substance (
JP-A-59-55795), forming a metal complex having light absorption in the long wavelength region (JP-A-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, 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 the formula, A is O, 5tSe, C*X is a norodan anion, and BF4''# ClO4-1R is an alkyl.] However, the cyanine dye represented by the above general formula also has problems with film forming properties and thermal light. It has an essential problem of lack of stability.As for 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 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 has the following features:
General formula [However, R1''2 in the formula is a hydrogen atom, a halogen atom, an alkyl group, or -N<Ph (ph; phenyl h group), R3 is an alkyl group having 1 to 6 carbon atoms, an aralkyl group, or a phenyl group, Y is -R4So,"(R4; alkyl group or aralkyl group having 1 to 20 carbon atoms), Y is -RS
o Na or -R4SO3NH(R5)3 (R4: alkyl group or aracyl group having 1 to 20 carbon atoms, R5: alkyl group having 1 to 18 carbon atoms), 2 is a benzene ring added to the benzene ring constituting indole It is characterized by having a recording layer containing an organic dye represented by the following.

The organic dye used in the present invention has in the methine chain,
It is possible to form a recording layer with excellent storage resistance and playback deterioration characteristics compared to organic dyes consisting only of methine chains such as CH and CH3 disclosed in JP-A-59-85791. R1. introduced into the cyclo ring. R2 is as described above, but especially when a halogen atom is used, CL a
When Br or an alkyl group is used, those having 1 to 3 carbon atoms are preferred.

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. can be improved.

Furthermore, since the organic dye used in the present invention has Y such as the sulfoalkyl group described above introduced into the indole, chemical stability, solvent solubility, and wettability to the substrate are improved.

Specific examples of the organic dyes represented by the above general formulas include those shown in the following structural formulas (1) to (6).

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 a spinner method, dipping method, doctor blade method, or roll coater. It can be obtained by forming a thin film on a substrate by a 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, 10 n
m~1000 nm s preferably 3゜nm~500
A range of nm is appropriate.

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

The recording layer is formed by the method described above. Furthermore, binder resin is added to the pigment in a weight ratio of 1 to 40% or 3 to 20% by weight.
By adding H, it is possible to form a film, and the film formability, heat resistance, and moisture resistance are 6 + fiL - ↓ 1.
L 2-Rumor 6-F 〉 Shi Pel
Examples of resins include acrylic, ester, nitrocellulose, ethylene,
Flopylene, car dl-), ethylene terephthalate,
Examples include homopolymers of epoxy, butyral, vinyl chloride, vinyl acetate, 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, 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 pigments used here include cyanine pigments and merocyanine colors! , anthraquinone dyes, triphenylmethane dyes, xanthine dyes, phthalocyanine dyes, and the like.

For example, it is also possible to add amylate metal complexes represented by the following general formulas (A) and (B) to prevent deterioration of the optical properties of the recording layer due to light, oxygen, and moisture.

1R5 However, R1* R21R4, R5 in the formula has 1 to 6 carbon atoms
Here, R represents an alkyl group having 1 to 6 carbon atoms.

... (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 perchlorate ion, fluoroborate ion, hexafluoroate ion, etc., and m is O or An integer of 1 or 2, A is the above m=0.1, and the compound is, for example, commercially available IRQ-002.
, IRQ-003 (all manufactured by Nippon Higyu Co., Ltd.)
etc.

However, R1 to R4 in the formula are an alkyl group or a phenyl group,
X, Y are hydrogen, alkyl group, halodane group, M is N1 +
This indicates a metal such as Co h F.ecr.

Examples of such a metal upper body include i'A1001-10
06 (all manufactured by Mitsui Toatsu Fine Co., Ltd.), N
-bis(0-xylene-4,5 diol)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. As the resin, for example, vinyl chloride, vinyl acetate, acrylic, ester, nitrocellulose, cargonate, epoxy, ethylene, 7'cr vinyl, butyral, etc. can be used alone or as a copolymer, and if necessary, oxidized. It is possible to contain an inhibitor, an ultraviolet light absorber, a leveling agent, a water repellent, etc. These can be formed using a spinner method, a dipping method, or a tractor blade method.

Examples of inorganic compounds include SiOSIO, At203
゜Sn021MgF2 or the like is used, and a thin film is formed by an ion beam, an alpha beam, or a sputtering method.

The AI protection layer also has the same structure as the intermediate layer, and has a structure similar to that of the intermediate layer.
It is used to protect the recording layer from moisture, scratches, dust, etc.

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 Radhe light 3 onto the recording layer 2 into a spot with a size of 0.8 to 1.5 μm using a condensing lens.

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 it 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 20, 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, 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, AA,
A reflective film such as Ag or others 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-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 (4) 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 2wm glass substrate and dried to a thickness of 80nm.
A recording medium was manufactured by forming a recording layer of m.

Example 3 An acrylic resin (manufactured by Mitsubishi Rayon Co., Ltd.: Dianal BR-) as a binder resin was added to the dye of structural formula (3) described above.
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 applied onto a 1.2 m thick glass substrate using a spinner coater and dried to form a 95 nm thick glass substrate. A recording medium was manufactured by forming a recording layer.

Example 4 The dye of structural formula (2) described above and an infrared absorber (trade name: IRG-003, manufactured by Nihon Kapaku Co., Ltd.) were mixed at a weight ratio of 3:1, and this was dissolved in methyl ethyl ketone. After making a 10% solution, it was applied onto a 1.2 m thick glass substrate using this melt spinner coater and dried to a thickness of 70 m.
A recording medium was manufactured by forming a recording layer with a thickness of 100 nm.

Example 5 The dye having the above structural formula (1) and the dye having the following structural formula (7) were mixed at a weight ratio of 2:1, dissolved in the same manner as in Example 1, and coated on a substrate. , dried to a thickness of 75 nm
A recording layer was formed to produce a recording medium.

... (7) Example 6 Structural formula (1
) After forming a recording layer with a thickness of 60 nm consisting of a dye of
A recording medium was manufactured by forming a reflective IJtm with a thickness of 30 nm by vacuum heating evaporation under rr conditions.

... (8) Comparative Example 1 A dye of the following structural formula (1) was dissolved in methylene chloride to a concentration of 2%.
After forming a solution, this solution is coated with a spinner coater to a thickness of L2.
- and dried to form a recording layer with a thickness of 80 nm 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 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 nm, and recorded. Media was manufactured.

For the recording layers of the recording media of Examples 1 to 6 and Comparative Examples 1 to 3, the reflectance of light with a wavelength of 830 nm was measured from the recording layer side using a spectrophotometer. Furthermore, the absorbance of each recording layer to light having a wavelength of 830 nm was measured. Historically, semiconductor radar light with a wavelength of 830 nm was focused on a spot with a diameter of t2 μm so that the medium surface output was 4 mW, and the focused radar light was moved from the substrate side of each recording medium at a speed of 9 m/sea. Writing was performed under the same conditions, and reproduction was performed using the same radar light at a reproduction output of 0.4 mW, and the recording sensitivity (recording energy threshold) and C7N value of the reproduction signal were measured. Furthermore, the recording media of Examples 1 to 6 and Comparative Examples 1 to 3 were left in a 95% atmosphere at 50° C. for 150 hours, and a heat-humidity test was conducted to measure the absorbance decrease rate and reflectance decrease rate before and after the exposure. I did it. A 500W tungsten light beam was applied to each recording medium at 25℃ and 60% atmosphere to 50aR.
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... Rade light, 4
... Intermediate layer, 5... Protective layer, 6... Spacer. Applicant's agent Patent attorney Tsuboi Original vehicle 1 Figure 2 Figure 3 Procedural amendment 1, Case indication (037) Olympus Optical Industry Co., Ltd. 4, Agent 3-7-2 Kasumigaseki, Chiyoda-ku, Tokyo uBE Building 〒10
0 Telephone 03 (502) 3181 (main representative) 6. Subject of amendment to Meiji II 7. Contents of correction (1): In the second line of page 3 of the specification, the phrase "(ax reflectance, absorption rate, etc.)" is corrected to "(e.g. reflectance, absorption rate, etc.)." (Z, on page 3 of the specification, lines 11-12, it says, ``On the other hand, it has a disadvantage of high reflectance, high thermal conductivity, and high specific heat.'' (3) On page 3, line 20 of the specification, it says, ``It has a high absorption rate, low heat conduction, and good productivity.'' Corrected to "High absorption rate, low thermal conductivity, and good productivity." (4) In the 5th line of page 5 of the specification, the word "formation" is corrected to "addition." (5) The general formula on page 5, line 13 of the specification car is corrected as follows. (7) In the 1st line of page 17 of the Meiji 11 harm, the phrase “metal complex” is corrected to “metal complex.” (8) In the 3rd line of the 17th page of the Mei 1llB, “N
-bis” should be corrected to “Ni-bis”. (9) The structural formula on page 22, line 1 of the specification is corrected as follows.

Claims (1)

[Claims] General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, R_1 and R_2 in the formula are hydrogen atoms, halogen atoms, alkyl groups, or ▲ Numerical formulas, chemical formulas, tables, etc. ▼
(Ph; phenyl group), R_3 is an alkyl group having 1 to 6 carbon atoms, an aralkyl group, or a phenyl group, Y is -R_4SO
_3^-(R_4; alkyl group or aralkyl group having 1 to 20 carbon atoms), Y' is -R_4SO_3Na or -R_
4SO_3NH(R_5)_3(R_4; carbon number 1-2
0 alkyl group or aralkyl group, R_5; carbon number 1-
18 alkyl group), Z represents a benzene ring added to a benzene ring constituting indole.