JPS62151383A - Optical recording medium - Google Patents

Abstract

PURPOSE:To enable high-density and high-sensitivity recording at a high speed by optical writing with small-sized light wt. semiconductive laser, by providing a recording layer formed by laminating a layer containing a diacetylene derivative compound and a layer containing a chloconic methine dye. CONSTITUTION:A diacetylene derivative compound (DA compound) is one represented by formula R-CidenticalC-CidenticalC-R' or a polymer thereof. A chloconic methine dye is a compound having a fundamental structure represented by formula 2 and has an absorption peak at 800-850nm and generates heat by infrared rays having said wavelength. A layer 3 containing the chloconic methine dye and a layer 4 containing the DA compound are successively laminated to a substrate 1 to form a recording layer 2. The proper thickness of each of the layers 3, 4 is about 300Angstrom -1mum and, as the substrate 1, a support material such as glass, a plastic plate, a plastic film, paper or metal can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical recording medium, and particularly to an optical recording medium suitable for optical writing using an infrared laser.

[Conventional technology]

Recently, optical discs have been attracting attention as a central player in office automation. Optical discs can record and store documents, literature, etc. on a single disc, so
Organize and manage documents etc. in the office efficiently. Various types of recording elements have been studied for this optical disc, but those using organic materials are attracting attention because of their cost and ease of manufacture.

Diacetylene derivative compounds are known as organic materials for such recording elements. Focusing on the thermochromic properties of these compounds, a recording technique for use in laser recording elements was disclosed in Japanese Patent Laid-Open No. 56-147807. There is. However, this specification does not mention what kind of laser was used or should be used, and merely states that recording was performed using a laser.

The inventors investigated the laser recording of this diacetylene derivative compound using various lasers, and found that although thermochromic recording is possible using a large, high-power laser such as an argon laser, a small and relatively It has been confirmed that laser recording cannot be performed when a low-power semiconductor laser (wavelength: 800 to 850 r+m) is used.

However, for practical recording media such as optical discs, it is required that optical writing be possible using a small, low-output semiconductor laser.

On the other hand, JP-A-58-181052 and JP-A-59-
No. 80443 discloses croconic methine dyes, and organic coatings containing these dyes absorb radiation in the radiation wavelength range of semiconductor lasers and generate heat, so that so-called heat mode recording, which forms a focus using laser energy, is carried out. We are disclosing what we can do. However, when performing recording by forming physical pits on the surface of a recording medium, it is necessary to ensure that the initial surface of the recording medium is sufficiently smooth and at the same time that the surface of the recording medium is not scratched even after recording. Sufficient care is required and it is relatively difficult to perform high-density, high-sensitivity, and high-speed recording.

[Problem that the invention seeks to solve]

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide an optical recording medium that can be optically written with a small and lightweight semiconductor laser.

Another object of the present invention is to provide an optical recording medium capable of high-density, high-sensitivity, and high-speed recording.

Still another object of the present invention is to provide an optical recording medium with excellent stability and high quality.

[Means for solving problems]

That is, the optical recording medium of the present invention is characterized by having a layer B formed by laminating a layer containing a diacetylene derivative compound and a layer containing a croconic methine dye.

Diacetylene derivative compound (hereinafter referred to as OA) used in the present invention
(abbreviated as compound) refers to the following general formula 8% (wherein R and R' are polar groups; saturated aliphatic hydrogen groups such as alkyl groups and cyclohexyl groups, which may be substituted with polar groups) ; a vinyl group which may be substituted with a polar group;
an olefinic hydrocarbon group such as a propenyl group; or a phenyl group, a naphthyl group, which may be substituted with a polar group;
An aromatic hydrocarbon group such as an alkylphenyl group,
Examples of the polar group here include a carboxyl group or a metal or amine salt thereof, a sulfonic acid group or a metal or amine salt thereof, a sulfamide group, an amide group, an amide group, an -imino group, and a hydroxy group.

Examples thereof include an oxyamino group, a diazonium group, a guanidine group, a hydrazine group, a phosphorus-resistant group, a silicon 1!1 group, an aluminate group, a nitrile group, a thioalcohol group, a nitro group, and a halogen atom. ) and their polymers.

On the other hand, the croconic methine dye used in the present invention is a compound having a substituent containing the following basic structure heterocycle (including an inner salt),
It is a compound that has an absorption peak at ~850 nva and generates heat when exposed to infrared light at this wavelength. These croconic methine dyes are typically of the following general formulas [technique] to [1].
7] is exemplified.

general formula [II basis,
n-butyl group, 5eC-butyl group, 1so-butyl group,
t-butyl group, n-amyl group, t-amyl group, n-hexyl group, n-octyl group, t-octyl group, etc.), substituted alkyl groups (e.g. 2-hydroxyethyl group, 3-hydroxypropyl group, 4 -Hydroxybutyl group, 2-7cetoxyethyl group, carboxymethyl group, 2-carboxyethyl group, 3-rupoxybrobyl group, 2-sulfoethyl group, 3-sulfopropyl group, 4-sulfobutyl group, 3
~sulfatepropyl group, 4-sulfatebutyl group, N-(methylsulfonyl)-cal8ylmethyl group,
3-(acetylsulfamyl)propyl group, 4-(acetylsulfamyl)butyl group, etc.), cyclic alkyl group (e.g. cyclohexyl group, etc.), allyl group (CH2
=CHCH2-), aralkyl group (e.g., benzyl group, 7enethyl group, α-naphthylmethyl group, β-naphthylmethyl group, etc.), substituted aralkyl group (e.g., carboxybenzyl group, sulfobenzyl group, hydroxybenzyl group, etc.) , an aryl group (such as a phenyl group) or a 1d-substituted aryl2. ti (eg, carboxyphenyl group, sulfophenyl group, hydroxyphenyl group, etc.). In particular, in the present invention, among these organic residues, hydrophobic ones are preferred.

Substituted or unsubstituted heterocycle 2 For example, a thiazole series nucleus (e.g. thiazole, 4-methylthiazole, 4-fecornazole, 5-methylthiazole, 5-fecornazole, 4,5-dimethylthiazole, 4,5 −
diphenylthiazole, 4-(2-chenyl)-thiazole, etc.), benzothiazole series nuclei (e.g. benzothiazole, 5-chlorobenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5.
G-dimethylbenzothiazole, 5-bromobenzothiazole, 5-phenylbenzothiazole, 5-methoxybenzothiazole, 6-methoxybenzothiazole, 5
．． 6-Simethoxybenzothiazole, 5.8-dioxymethylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, 4,5,6
．． 7-titrahydrobenzothianol, etc.), naphthothiazole series nuclei (e.g. naphtho[2,1-dl thiazole, natto (1,2-cll thiazole, 5-methoxynaphthoH,,2-dl thiazole, 5- Ethoxynaphtho [1,2-dithianol, 8-methoxynafh [2,1-dl thiazole, 7-medoxynaf]
[2,1-dl chiatool, etc.), thionaphthene [
7,6-d]thiazole series nuclei (e.g. 7-medoxythiothiftene[7,II-d]thiazole), oxazole series nuclei (e.g. 4-methyloxazole, 5-
Methyloxazole, 4-phenyloxazole, 4.
5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole), penzoxazole series nuclei (e.g. penzoxazole, 5-chlorobenzothiazole, 5-methylbenzothiazole), sol, 5-phenylhenoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 5-methoxybenzoxazole,
6-methoxybenzoxatool, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphthoxazole series nuclei (e.g. naphtho[2
, 1-d]oxazole, naphtho (1,2-dl oxazole, etc.), selenazole series nuclei (e.g. 4-methylselenanol, 4-phenylselenazole, etc.),
Nuclei of the benzoselenazole series (e.g. benzoselenazole, 5-chlorobenzoselenazole, 5-methylbenzoselenazole, 5,6-dimethylhenzoselenazole,
5-methoxybenzoselenazole, 5-methyl-6-methoxybenzoselenazole, 5,6-cyoxymethylenehenzoselenazole, 5-hydroxybenzoxazole, 4.5,8,7-titrahydrohenzoselenazole, etc. ), nuclei of the naphthoselenazole series (e.g. naph1-
[2,1-dl selenazole, naphtho[1,2-d
l selenazole), thiazoline series Fll core (e.g. thiazoline, 4-methylnaazoline, 4-hydroxymethyl-4-methylthiazoline, 4.4-bis-hydroxymethylthiazoline, etc.), oxazoline series core (e.g. oxazoline), selenazoline series (e.g. selenazoline), 2-quinoline series nuclei (e.g. quinoline, 6-methylquinoline, 6-chloroquinoline, 6-medoxyquinoline, 6-nitoxyquinoline, 6-hydroxyquinoline), 4-quinoline series nuclei (e.g. For example, quinoline,
3.3
- nuclei of the dialkylindolenine series (e.g. 3,3-dimethylindolenine, 3,3-dimethyl-5-chloroindolenine, 3,3,5-)dimethylindolenine, 3
, 3.7-trimethylindolenine), pyridine series nuclei (e.g. pyridine, 5-methylpyridine), or benzimidazole series nuclei (e.g. [-ethyl-5.6
-dichlorobenzimidazole, 1-hydroxyethyl-5,6-dichlorobenzimidazole, 1-ethyl-
5-chlorobenzimitazole, l-ethyl-5,6-
Dipromobenzimitazole, 1-ethyl-5-phenylbenzimidazole, 1-ethyl-5-fluorobenzimidazole, 1-ethyl-5-cyanobenzimidazole, 1-(β-acetoxyethyl)-5-cyanobenzo Imidazole, 1-ethyl-5-chloro-6-cyanobenzimidazole, -ethyl-5-fluoro-6
-Diatsubenzimidazole, -Ethyl-5-7 cetylbenzimidazole! sol, 1-ethyl-5-carboxybenzimidazole, 1-ethyl-5-ethoxyluponylbenzimitazole, l-ethyl-5-sulfamylbenzimidazole, l-ethyl-5-N-ethylsulfami Rubenzimidazole, 1-ethyl-5.8-
Difluorobenzimidazole, 1-ethyl-5,8-
Dicyanobenzimidazole, 1-ethyl-5-ethylsulfonylbenzimidazole, l-ethyl-5-methylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylbenzimidazole, 1-ethyl-5
- triple O-O methylsulfonylbenzimidazole,
1-ethyl-5-trifluoromethylsulfinylbenzimidazole, etc.) R3 and represents an alkyl group such as methyl, ethyl, propyl, butyl, etc. Also, R3 and R4 can form a ring such as morpholino, piperidinyl, or pyrrolidino with the nitrogen atom.RS, R6, R
7 and the total are hydrogen atoms, alkyl groups (methyl, ethyl,
(propyl, butyl, etc.), an alkoxy group (methoxy, ethoxy, propoxy, butoxy, etc.), or a hydroxy group. Furthermore, R5 and R6 can be combined to form a benzene ring, and R5 and R6 can be combined with R7 and R6 to form a benzene ring.
8 can be combined with each other to form a benzene ring.

X is chloride ion, bromide ion, iodide ion, perchlorate ion, benzenesulfonate ion, P
−) luenesulfonate ion, methyl sulfate ion,
represents an anion such as ethyl sulfate ion or propyl sulfate ion;
e-S03, OSO3. -Coo, so
2NH-, -S02-N-C: 0-, -SO2-N
-SO, does not exist when it contains -.

■X represents a cation such as a hydrogen cation, sodium cation, ammonium cation, potassium cation, or pyridium cation. n and m are 0 or l
It is.

Next, representative examples of the croconic methine dye used in the present invention are listed below, but for convenience, general formula [I] or [
III] is represented by the betaine structure. However, in the preparation of these dyes, a mixture of dyes in betaine form or salt form is obtained, and therefore they are generally used as a mixture.

Representative example (17) of general formulas [I] and [II] Oe (21). θ(23)
. θ (24). e(28)
0e(27)
. e Representative example (35) of general formula [01], [IV] e.

(36) e.

(37) eO (38) o.

(39) θ.

(40) e.

Croconic methine dye i± of (1) to (42) above,
A typical structure of the optical recording medium of the present invention is shown in FIGS. 1a and 1b.
An example is shown in the figure. In this example, a recording layer 2 is formed by sequentially laminating a layer 3 containing the croconic methine dye and a layer 4 containing the OA compound on a substrate 1. A layer 3 and a layer 4 are laminated. The order is not limited to the embodiment shown in this figure, and the layers may be stacked in the reverse order, but it is preferable to stack the layers so that the layer 4 containing the OA compound appears on the surface side of the recording layer 2. If necessary, other layers such as a transparent protective layer may be provided on the recording layer 2, for example.

The film thicknesses of layer 3 and layer 4 are each 300A to 1-
degrees are suitable, particularly the range from 500 to 3000 is preferred.

As the substrate 1 of the optical recording medium of the present invention, various supporting materials such as glass, a plastic plate such as acrylic resin, a plastic film such as polyester, paper, and metal can be used. When performing recording, a material that transmits recording radiation of a specific wavelength is used.

In order to form the layer 3 containing the croconic methine dye, a typical method can be adopted in which the croconic methine dye is dissolved in a suitable volatile solvent to prepare a coating liquid and the coating liquid is applied. A binder made of a natural or synthetic polymer may be appropriately added to the coating liquid in order to improve the adhesion to the substrate 1 and the layer 4 containing an OA compound. Furthermore, various additives may be added to improve the stability and quality of each layer.

The solvent for applying the croconic methine dye is methanol, when the croconic methine dye is in an amorphous state.
Alcohols such as ethanol and impropatol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide; tetrahydrofuran, dioxane, and ethylene Examples include ethers such as glycol monomethyl ether; esters such as methyl acetate and ethyl acetate; aromatics such as benzene, toluene, xylene, and ligroin; and when croconic methine is in the form of particles, dichloromethane, chloroform, Carbon tetrachloride, 1.1-
Dichloromethane, 1,2-dichloromethane, 1,1.
2-) Halogenated hydrocarbons such as dichloromethane, chlorobenzene, bromobenzene, 1,2-dichlorobenzene, and the like.

On the other hand, in order to form the layer 4 containing the OA compound, a typical method can be adopted in which a fine crystal powder of the OA compound is dispersed in a suitable volatile solvent to prepare a coating liquid, and then the coating liquid is applied. In order to improve the adhesion with the substrate 1 and the layer 3 containing the croconic methine dye, a binder made of natural or synthetic polymer may be appropriately dissolved in the coating liquid. 1. Various additives may be added to improve quality.

Suitable dispersion media for OA compounds include n-hexane, n
Examples include aliphatic hydrocarbons such as -hebutane, n-octane, and cyclohexane.

However, since the DA compound is a highly crystalline compound, even if it is once dissolved in a solvent and this solution is applied onto a substrate, recrystallization proceeds during the drying process and grains are obtained. Therefore, not only a dispersion but also a solution of the OA compound may be used. In this case, the same solvents as those mentioned as the solvent for biryllium dyes can be used.

The coating solution obtained in this way can be applied by spinner rotation coating method, dip coating method, spray coating method, pea coating method, wire per coating method, and blade coating method.

Techniques such as a roller coach ink method and a curtain coating method are used.

The optical recording medium of the present invention constructed in this manner enables high-density, high-resolution recording using a semiconductor laser.

The optical recording medium of the present invention allows various types of optical recording to be performed; however, by applying light or heat, the absorption wavelength of the recording layer changes and the apparent color changes. The recording mechanism using a semiconductor laser will be briefly explained below.

The OA compound (excluding the polymer) is initially almost colorless and transparent, but when the recording layer is irradiated with ultraviolet rays, it polymerizes and changes into a polyacetylene derivative compound. This polymerization occurs by irradiation with ultraviolet rays, etc., and does not occur simply by the application of thermal energy.

As a result of this polymerization, the recording layer has a maximum absorption wavelength in the range of 620 to 880 nm and changes in color from blue to dark. The change in hue due to this polymerization is an irreversible change, and once the recording layer changes from blue to dark, it will not return to a colorless transparent film.Also, the polyacetylene derivative compound that has changed from blue to dark will not be heated to about 50°C or above. When heated, it now has a maximum absorption wavelength of about 540 rv and changes to a red film.

This change is also an irreversible change.

Therefore, optical recording using the optical recording medium of the present invention is performed by the following mechanism.

First, when the entire recording layer of the optical recording medium shown in FIG. 1a of the present invention is irradiated with ultraviolet rays, the OA compound in the R layer polymerizes and changes into a polyacetylene derivative compound, so that the recording layer 2 becomes a blue to dark-colored film. and changes. Note that this step is not necessary when a polyacetylene derivative compound is used as the DA compound. Next, at a predetermined position on this recording medium, a light beam with a wavelength of 800 to 850 nm blinks in accordance with the information signal.
When irradiated with a semiconductor laser beam 6, the polyacetylene derivative compound does not absorb this laser beam 6, but as shown in FIG. This croconic methine dye absorbs 6 and generates heat (the exothermic site is shown as 5).
This is transmitted to the polyacetylene derivative compound in the layer 4 containing the A compound, and the color changes to red, as shown in FIG. 1b. Thus, depending on the input information, the recording site 7 on the recording layer
Optical recording is performed by color change.

〔Effect of the invention〕

The effects of the optical recording medium of the present invention are listed below.

(1) A homogeneous recording layer can be manufactured at low cost even on a large-area support.

(2) Since the recording layer is provided with a layer containing croconic methine dye, recording can be performed using a small and lightweight semiconductor laser.

(3) Since it is possible to record using changes in the hue of the recording layer due to light irradiation, high-speed, high-density, and highly sensitive optical recording can be performed.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples.

Example 1 A coating solution obtained by dissolving 1 part by weight of the croconic methine dye represented by the above dyestuff (12) in 1 part by weight of methylene chloride was applied to a glass disc substrate (thickness) attached to a spinner coating machine. After dropping a small amount onto the center of a substrate (1.5 mm in diameter and 200 mm in diameter), the coating was applied by rotating a spinner at a predetermined number of rotations for a predetermined time, and dried at room temperature, so that the thickness of the dried coating film on the substrate was 100 A.

300A, 100OA, 3000A and 6000
We prepared a number of items for each.

Next, the general formula c12H2s-c=c-cmiC-C3
A coating solution obtained by dispersing 1 part by weight of a crystalline fine powder of a diacetylene derivative compound represented by H,6-C0OH is prepared, and applied onto the surface of a substrate on which a coating film of the croconic methine dye prepared previously has been formed. A small amount of this coating solution was added dropwise, and the spinner was rotated at a predetermined rotation speed for a predetermined time in the same manner as before, so that the thickness of the diacetylene derivative compound layer after drying on the surface of the croconic methine dye coating was 100 A and 200 A. , 10
00 people, 3000 A and 06000 people, total 25
A seed optical recording medium was prepared.

Comparative Example 1 An optical recording medium was produced in which a coating film of a diacetylene derivative compound was formed to a thickness of 1000 mm directly on a substrate without forming a coating film of a croconic methine dye.

Recording Test 1 The optical recording medium prepared in Example 1 and Comparative Example 1 was
The recording layer was uniformly and sufficiently irradiated with nanometer ultraviolet rays to turn the recording layer into a blue film. Next, the output is 3mW and the wavelength is 830nm.

A semiconductor laser beam with a beam diameter of 1 mm was irradiated at a predetermined position on the surface of each optical recording medium according to the input information (200 ns/l bit open at the time of irradiation) to form a red recorded image on the blue recording layer. .

The evaluation of the recording results is shown in Table 1. The evaluation was based on a comprehensive evaluation of recording sensitivity, image resolution, and image density. Particularly good results were evaluated as ■, good results were O1, and those in which recording was not possible or poor were evaluated as ×.

Table 1 Example 2 A croconic methine dye-containing layer having a thickness of 200 OA was prepared in the same manner as in Example 1 using a mixed solution of 3 parts by weight of croconic methine dye, 1 part by weight of nitrocellulose and 22 parts by weight of methylene chloride as the coating liquid. It was formed on a glass disk substrate by the method described above.

Then, on this croconic methine dye-containing layer, a layer with a thickness of 2
A diacetylene derivative compound-containing layer of 000 A was laminated using a mixed solution of 3 parts by weight of a diacetylene derivative compound, 1 part by weight of nitrocellulose, and 20 parts by weight of methylene chloride as a coating liquid to prepare an optical recording medium.

Comparative Example 2 The same procedure as in Example 1 was carried out using a solution prepared by dissolving 3 parts by weight of croconic methine dye and 1 part by weight of nitrocellulose in 22 parts by weight of methylene chloride without using a diacetylene derivative compound. The thickness of the recording layer is 200 mm depending on the method.
An OA optical recording medium was produced.

Recording Test 2 For the optical recording media created in Example 2 and Comparative Example 2,
Regarding the optical recording medium of Example 2, the irradiation time of the semiconductor laser beam was varied (irradiation time 100ns to 800ns).
Recording was carried out in the same manner as in Recording Test 1, except that the recording was performed (ns/1 beat, 2 beats). On the other hand, for the optical recording medium of Comparative Example 2, a semiconductor laser beam was directly applied to the recording layer surface at the same output and at a predetermined position on the surface of the optical recording medium by varying the irradiation time according to the input information without performing ultraviolet irradiation. Recording was performed by irradiating the top (irradiation time 500 ns to 5 ls/1 bit) to form pits.

For the optical recording medium of Example 2, the irradiation time was 350
Particularly good recording was achieved in the case of ns or more, but the optical recording medium prepared in Comparative Example 2 was observed under a microscope and found that it took 2 pLs to clearly form one pit.
It was found that the irradiation time was longer than that required.

Example 3 General formula C,2H25-C=C-C:=C-[:8H,6
Instead of the diacetylene derivative compound represented by -GOOH, the general formula C8H, -C=C-C=C-C2H4-C
The thickness of the diacetylene derivative compound-containing layer was 200 OA by the same method as in Example 1 except that a fine crystal powder of the diacetylene derivative compound represented by 0OH was used.
and the thickness of the croconic methine dye-containing layer is 2000
An optical recording medium was fabricated.

Examples 4 to 11 In place of the croconic methine dye represented by dye 6 (12), dyes such as (1), (23), (28),
(31), (37).

Optical recording media were prepared in the same manner as in Example 3, except that the croconic methine dyes represented by (39), (40), and (42) were used, respectively.

Recording Test 3 A recording test was conducted in the same manner as Recording Test 1 using the optical recording media prepared in Examples 3 to 11. The evaluation of this recording result is shown in Table 12.

Table 2

[Brief explanation of drawings]

FIG. 1a and FIG. 1b are schematic cross-sectional views showing one embodiment of the structure of the optical recording medium of the present invention and the recording state 7gi. Substrate 2: Recording layer 3: Croconicmethine dye-containing layer 4 Nidiacetylene derivative compound-containing layer 5: Heat generating area 6: Laser beam 7: Red discoloration area (recording area)

Claims (1)

[Claims] 1) An optical recording medium characterized by having a recording layer formed by stacking a layer containing a diacetylene derivative compound and a layer containing a croconic methine dye.