JPH01145195A - Optical recording medium - Google Patents

Abstract

PURPOSE:To enhance durability, reflectance and economy by providing a recording layer comprising at least one specified thioanthracyanine compound, on a transparent substrate. CONSTITUTION:A recording layer containing a compound of the formula is provided on a transparent substrate. In the formula, each of X1-X4 is independently carbon or sulfur; each of R1-R32 is independently hydrogen, a halogen, cyano, nitro, carboxyl, sulfonic group, substd. or unsubstd. aliphathic hydrocarbon group, substd. or unsubstd. aromatic hydrocarbon group, substd. or unsubstd. aromatic heterocyclic group or the like; M is hydrogen or a metal with or without a halogen, oxygen, -(OR45)m or -(OSiR46R47R48)n, where R45, R46, R47 and R48 have the same definition as that of R1-R32, and each of m and n is 0, 1 or 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical recording medium that can be additionally recorded using a focused beam of a semiconductor laser, and more particularly to a computer external memory.

The present invention relates to optical recording media used to record various types of information such as images and audio.

(Prior art and problems) The above-mentioned recordable optical recording medium is tellurium.

-Recording media having an inorganic recording layer made of a thin film of a low-melting metal such as a tellurium alloy or a bismuth alloy are beginning to be put into practical use.

However, these recording media have low productivity because they use thin film formats in vacuum, such as vacuum evaporation and sputtering.Furthermore, the recording layer has a high thermal conductivity, which limits the recording density. Since toxic substances are used, hygiene is a problem.

In order to solve these problems, in recent years, methods of using organic dyes as recording media have been studied.
A recording medium with a recording layer made of an organic dye that absorbs in the semiconductor laser oscillation wavelength region, such as a naphthoquinone dye (Japanese Patent Application Laid-open No. 112793/1983), a phthalocyanine dye (US Pat. No. 4,298,975), or a naphthalocyanine dye (US Pat. No. 4,492,750). is proposed. however,
Recording media using organic dyes that have been proposed so far have not been able to provide sufficient characteristics in terms of durability and reflectance.

It has a disadvantage that it has poor solubility in solvents and cannot be applied to thin film forming methods using economically advantageous coating methods.

(Means for Solving the Problems) The present inventors have made intensive studies to improve the problems of recording media using organic dyes, and have found that the recording medium has excellent practical characteristics and is also economically advantageous. This led to the invention of a new optical recording medium.

That is, 1 the present invention provides the following general formula (I) on a transparent substrate.
This is an optical recording medium having a recording layer containing a compound represented by:

In the formula, X to X4 each independently represent a carbon atom or a sulfur atom, and R+ to R2 each independently represent a hydrogen atom, a halogen atom, a cyano group, a nitro group, a carboxylic acid group, a sulfonic acid group , substituted or unsubstituted aliphatic hydrocarbon group, substituted or -C○! I(4!,
-N -To -Shaku 4 pieces.

R44(YCHzCHz) represents IZ-.

(Here, Rff3 to R44 represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group. each independently represents an oxygen atom or a sulfur atom, and l represents a positive integer.) M is a halogen atom, an oxygen atom, *ORas) m or +OS i R46R4? R411) Represents a metal atom that may have n or a hydrogen atom. (Here, R4
S, Rab+ R4? l R411 is R, or R3
Same as 2 and 1m.

All n represents 0.1 or 2. ) To further explain the substituents, Ro to R24 are a hydrogen atom, a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom, a cyano group, a nitro group, a carboxylic acid group, a sulfonic acid group, a methyl group, or an ethyl group.

Substituted or unsubstituted aliphatic hydrocarbon groups such as t-butyl group, n-stearyl group, trichloromethyl group, aminomethyl group, hydroxymethyl group, phenyl group.

Naphthyl group, anthryl group, 2-methylphenyl group.

Substituted or unsubstituted aromatic hydrocarbon groups such as 4-chloromethyl group and 4-dimethylaminonaphthyl group, or pyridyl group, carbazolyl group, and dibenzofuryl group.

Substituted or unsubstituted aromatic heterocyclic groups such as benzothiazolyl group and 4-methylpyridyl group, and methoxy group.

Ethoxy group, stearyloxy group, phenoxy group.

hexylthio group, t-butylthio group, phenylthio group,
Amino group, n-butylamino group, diethylamino group, diphenylamino group, dibenzylamino group.

5OzNH'C4H9, -3OzN (CHz)z.

Fe, Co, Ni, Zn, Mn, Pb, Si, Mg.

All-C1l, In-C12, Ti=O, V-0, S
i(OCgHs)g, All O″CsH++, S
t+os 1(CHs)s)z, etc., but is not limited to these.

The compound represented by the general formula (I) has large absorption in the visible to near infrared region, and is suitable for recording and reproducing by laser.

The compound represented by the general formula (CI) used in the present invention generally comprises at least one compound represented by the following general formula (II) together with urea and various metal salts, preferably in an organic solvent. It can be manufactured by heating.

In the formula, X represents a carbon atom or a sulfur atom, and A1 to A represent R1 to Ro in general formula (I), respectively.
It is the same as ll.

In the production of these compounds, alcohols, glycols, and aliphatic organic solvents having hydroxyl groups can be widely used.

Furthermore, various metal salts can be used as the raw material metal salt.

Representative examples of the thioanthracyanine compounds represented by the general formula CI) used in the present invention are listed below.

The present invention is not limited to the following representative examples.

S mosquito Every time too + Yu ,ingredient ◆ ? Engineering θ Li.

a 〆N d＼ Shichigo f? The transparent substrate used in the present invention preferably has a transmittance of light for writing and reading signals of preferably 85% or more and has small optical anisotropy. For example, glass or thermoplastic resins such as alkyl resins, polycarbonate resins, polyester resins, polyamide resins, vinyl chloride resins, polyvinyl ester resins, polystyrene resins, polyolefin resins (poly-4-methylpentene, etc.), and polyethersulfone resins. Examples include substrates using thermosetting resins such as epoxy resins, allyl resins, etc. Among these, the above-mentioned thermoplastic resins are preferred from the viewpoint of ease of molding and ease of providing guide grooves, address signals, etc., and acrylic resins and polycarbonate resins are particularly preferred from the viewpoint of optical properties and mechanical properties.

In the present invention, the thickness of these transparent substrates is .

There is no particular restriction, and it may be in the form of a plate or a film. Also,
Its shape may be nine circles or card-like, and its size is not particularly limited.

Further, the transparent substrate of the present invention usually has unevenness for preformatting, such as guide grooves for position control during recording and reading, address signals, and various marks, as described above. Molding (injection,
It is preferable to apply it using a stamper or the like during compression (compression, etc.).

1. Fixing the recording layer containing the compound of the present invention on a transparent substrate in the optical recording medium of the present invention.

For example, the film can be made into a thin film by a vacuum evaporation method, a sputtering method, an ion plate method, an LB method, or the like.

Since these methods require complicated operations and are inferior in productivity, so-called coating methods are most preferred. When forming a recording layer by a coating method, the phthalocyanine derivatives are alcohols, ketones, amides, sulfoxides, ethers, and esters.

It is applied by dispersing or dissolving it in a general organic solvent such as aliphatic halogenated hydrocarbons or aromatic hydrocarbons.

Further, at this time, a polymer binder may be added depending on the case. Polymer binders include vinyl chloride resin, acrylic acid resin, and polyester resin.

Examples include polyethylene resin, polyamide resin, polycarbonate resin, epoxy resin, methacrylic acid resin, vinyl acetate resin, nitrocellulose, polypropylene resin, polyethylene terephthalate resin, phenol resin, and copolymers thereof. In this case, the ratio of the resin to the compound of the present invention is preferably 10 wt% or less.

The recording layer containing the compound of the present invention formed on a transparent substrate has a thickness of 10 μm or less, preferably 500 μm to 2 μm. In addition, by exposing the thin film to the vapor of an organic solvent such as chloroform, tetrahydrofuran, or toluene after coating, the absorption wavelength of the thin film shifts to longer wavelengths, and the sensitivity to light in the oscillation wavelength range of semiconductor lasers can be significantly improved. There is also.

In addition, in order to protect these recording layers, ANzO,...
St○21 S 10. A protective layer may be provided by vapor depositing an inorganic compound such as SnO. Also as a protective layer.

A polymer may also be applied.

Recording on the recording medium obtained as described above is carried out by irradiating the recording layer provided on the substrate with laser light, preferably semiconductor laser light, focused to about 1 μm.

The area irradiated with the laser light will decompose, evaporate, melt, etc. due to absorption of laser energy. This is done by reading the difference in reflectance between a portion of the layer where a thermal state change has occurred and a portion where no change has occurred.

Further, it is also possible to use the compound of the present invention by mixing and dispersing or mixing and dissolving other dyes.

Examples of known pigments that can be used in combination include:
Examples include aromatic or unsaturated aliphatic diamine metal complexes, aromatic or unsaturated aliphatic dithiol metal complexes, phthalocyanine complexes, naphthalocyanine complexes, squalium dyes, naphthoquinone complexes, anthraquinone dyes and polymethine dyes. It will be done.

As the light source, various lasers such as a He--Ne laser, an Ar laser, and a semiconductor laser can be used, but semiconductor lasers are particularly preferred in terms of cost and size. As a semiconductor laser, the center wavelength is 830 nm,
Lasers of 780 nm and shorter wavelengths can be used.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples.

In the example, the middle part is the part by weight.

Example 1 A solution consisting of 3 parts of the compound (7) of the present invention and 100 parts of methyl cellosolve was dropped onto an acrylic resin substrate, and then the substrate was rotated at a speed of 80 Orpm for 20 seconds.

Next, this substrate was dried at 90° C. for 1 hour to obtain a recording medium. The thickness of this recording layer was 900.

Mount this optical recording medium on the turntable.

While rotating the turntable at 80 rpm, recording was performed by shining a gallium-aluminum-arsenide semiconductor laser (830 parts m) focused at 1°0 μm onto the recording layer in a track shape at 5 mW and 8 MHz.

When the surface of the optical recording medium on which this recording was performed was observed under a scanning electron microscope, clear pits were observed. Furthermore, when this optical recording medium was irradiated with a low-power gallium-aluminum-arsenic semiconductor loser light and one reflected light was detected, it showed a waveform with a practically sufficient S/N ratio.

Example 2 Two parts of nitrocellulose resin were dissolved in 10 parts of methyl ethyl ketone, and 4 parts of the compound (3) of the present invention and 96 parts of dichloroethane were mixed and dissolved with the above resin solution.

After dropping this solution onto a Pyre Nox substrate, the substrate was rotated at 80 rpm. Next, heat this board to 90°C.
The mixture was dried for 2 hours to obtain a recording medium.

The thickness of this recording layer was 800.

Further, when recording was performed on this recording medium in the same manner as in Example 1, clear pits were observed on the surface of the recording layer.

Furthermore, when the reflected light with respect to the incident laser beam was detected in the same manner as in Example 1, a waveform having a practically sufficient S/N ratio was shown.

Example 3 Compound (8) of the present invention was added to 100 parts by weight of ethyl cellosolve.
After dissolving 3.5 parts by weight and applying this solution onto a polycarbonate resin substrate using an 800 rpm spinner coating method, it was dried at 80 to 90° under reduced pressure for 1 hour to give a
Obtained a human record layer.

When recording was performed on the optical recording medium thus produced in the same manner as in Example 1, clear pits were observed in this recording layer using an electron microscope. In addition, when the reflected light of the incident laser was detected in the same manner as in Example 1, the S/S was sufficient for practical use.
A waveform with an N ratio was shown.

Example 4 Compound (2) of the present invention was placed on an acrylic substrate with a thickness of 1 m + m at a vacuum degree of 10-' Torr with the substrate temperature at room temperature.
was deposited to obtain a recording layer with a thickness of approximately 700 nm.

When recording was performed on the optical recording medium thus produced in the same manner as in Example 1, clear pits were observed using an electron microscope. Further, when the reflected light of the incident laser beam was detected in the same manner as in Example 1, a waveform having a practically sufficient S/N ratio was shown.

〔Effect of the invention〕

The present invention has the above-mentioned structure, and is based on a chemical structure.

It has the characteristics of being physically stable and capable of producing a highly sensitive recording medium in the semiconductor laser oscillation region.

Claims (1)

[Claims] An information recording medium that performs recording by causing a state change by irradiation with high-density energy such as a laser beam, in which at least one thioanthracyanine compound represented by the following general formula [I] is provided on a transparent substrate. An optical recording medium characterized by having a recording layer containing. General formula [
I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, X_1 to X_4 each independently represent a carbon atom or a sulfur atom. Also, R_1 to R_3_2
each independently represents a hydrogen atom, a halogen atom, a cyano group, a nitro group, a carboxylic acid group, a sulfonic acid group, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic hydrocarbon group. Substituted aromatic heterocyclic group, -OR_3_3, -SR_3_4, ▲mathematical formula, chemical formula,
There are tables, etc.▼, formula% formula, ▲mathematical formula, chemical formula, table, etc.▼, -NHCOR_4_1, -CO_2R_4_
2, -N=N-R_4_3R_4_4(YCH_2CH
_2) Represents _lZ-. (Here, R_3_3 to R_4_4 represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group. each independently represents an oxygen atom or a sulfur atom, and l represents a positive integer.) M is a halogen atom, an oxygen atom, ■OR_4_5)_m or ■OSiR_4_6R_4_7R_4_8)_n
Represents a metal atom that may have , or a hydrogen atom. (Here, R_4_5, R_4_6, R_4_7, R_4_
8 is the same as R_1 to R_3_2, and m and n each represent 0, 1 or 2. )