JPH01130981A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium with sufficient durability, high reflective factor and a recording layer which can easily be formed by providing a recording layer containing at least one kind of specific compound on a transparent substrate. CONSTITUTION:A recording layer containing a compound as shown by a formula [X1-X4 are a carbon atom or a sulphur atom independently, R1-R2 a hydrogen atom, a halogen atom, a cynano group, a nitro group, a carboxylic acid group, a sulphonic acid group, a substituted or non-substrate aliphatic hydrocarbon group, a substituted or non-substituted aromatic hydrocarbon group, a substituted or non-substituted armoatic heterocyclic ring group, M represents a halogen atom, an oxygen atom, a metallic atom which may have (-OR37)m or (-OSiR38 R39R40)n, or a hydrogen atom], is fixed on a transparent substrate and used as a film. Then recording on a recording medium is made by projecting a laser beam condensed in a flux of about 1mum on the recording layer. As a result, a high sensitivity optical recording medium with high chemical stability and durability plus high reflective factor in a semiconductor oscillation area is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical recording medium that is recordable by high-density energy irradiation such as a focused beam of a semiconductor laser. More specifically, the present invention relates to an optical recording medium used for recording various information such as computer external memory, images, and audio.

゛・Bi■ Tellurium, tellurium alloy,
Recording media having an inorganic recording layer made of a thin film of a low-melting metal such as a bismuth alloy are beginning to be put into practical use. However, these recording media have low productivity because they rely on thin film formation in a vacuum before vacuum evaporation or sputtering, and the recording layer has a high thermal conductivity, which limits the recording density. Since substances are used, there is a problem in terms of hygiene.

In order to solve these problems, methods of using organic dyes as recording media have recently been studied. for example,
Polymethine dye (Japanese Unexamined Patent Publication No. 58-112790)
, naphthoquinone dye (JP-A-58-112793), phthalocyanine dye (US Pat. No. 4,298,975)
No. 449), naphthalocyanine dye (U.S. Pat. No. 449)
A recording medium having a recording layer made of an organic dye having absorption in the semiconductor laser oscillation wavelength region, such as Japanese Patent No. 275, has been proposed.

However, the recording media using organic dyes that have been proposed so far have not been able to obtain sufficient characteristics in terms of durability and reflectance, or have poor solubility in solvents, making it difficult to form thin films using economically advantageous coating methods. The disadvantage is that the formation method cannot be applied.

The purpose of the present invention is to solve the problems of recording media using organic dyes, and to provide an optical system that provides easy formation of a recording layer that has sufficient durability and reflectance, and can employ an economically advantageous coating method. The purpose is to provide recording media.

The present invention is an optical recording medium in which a recording layer containing at least one of the following compounds (maximum [I]) is provided on a transparent substrate.

[In the formula, Xl to X each independently represent a carbon atom or a sulfur atom, and R3 to R7 each independently represent a hydrogen atom, a halogen atom, a cyan group, a nitro group, a carboxylic acid group, a sulfonic acid group, a substituted or an unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, =4= -N-N-R, s, and R, 36 is (YCH2CH
2), represents Z-, (where R2 to R16 are a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocarbon group) represents a ring group, Y and 2 each independently represent an oxygen atom or a sulfur atom, and p represents a positive integer of 1 to 20.) M is a halogen atom, an oxygen atom, +OR37) or 1,000 SiRj8R3, R1 (Here, R1 to Rlo represent the same meanings as R1 to R2, and both shoulder and n represent 0.1 or 2. )].

More detailed examples of the substituents R to R21 of the compound used in the present invention are as follows.

Hydrogen atom, or halogen atom such as chlorine atom, bromine atom, or iodine atom, cyano group, nitro group, carboxylic acid group, sulfonic acid group, or methyl group, ethyl group, 7-butyl group, n-stearyl group, trichlor Substituted or unsubstituted aliphatic hydrocarbon groups such as methyl group, aminomethyl group, hydroxymethyl group, phenyl group, naphthyl group, anthryl group, 2-methylphenyl group, 4-chloromethyl group, 4-
Substituted or unsubstituted aromatic hydrocarbon groups such as dimethylaminonaphthyl groups, pyridyl groups, carbazolyl groups,
Substituted or unsubstituted aromatic heterocyclic groups such as dibenzofuryl group, benzothiazolyl group, 4-methylpyridyl group, 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, -8o
2NH, etc., but is not limited to these substituents.

M is H, Na, Li, Cu, Fe, Co, Ni, Zn
, Mn, Pb, Si, Mg, Al-Cl, In-
Cl.

Ti; ○, V□O, S i+o C2HS)2, A I
-0n CsH8, Si-[-OS + (CH3)
It represents 1, 2, etc., but is not limited to these.

The compound of general formula [1] used in the present invention has large absorption in the visible to near infrared region, and is suitable for recording and reproducing by laser.

The compound of general formula [I] used in the present invention is generally:
-Maximum [■koUIn the formula,
has the same meaning as ] It can be produced by heating at least one of the above compounds together with urea and various metal salts in an organic solvent.

As the organic solvent, alcohols, glycols, and aliphatic organic solvents having hydroxyl groups can be widely used. As the metal salt, various conventionally known metal salts can be used.

Representative examples of the thionaphthalocyanine compound represented by the general formula [I] used in the present invention will be more specifically illustrated below, but the present invention is not limited to the following representative examples.

The transparent substrate used in the present invention preferably has a light transmittance of 85% or more for writing and reading signals, and has small optical anisotropy. For example, glass, acrylic resin, polycarbonate resin,
polyester resin, polyamide resin, vinyl chloride resin,
Polyvinyl ester resin, polystyrene resin, polyolefin resin (poly-4-methylpentene, etc.), = 13
-114- This is a substrate using a thermoplastic resin such as polyether sulfone resin, or a thermosetting resin such as epoxy resin or allyl resin.

Among these, thermoplastic resins are preferred because of ease of molding, ease of providing guide grooves, address signals, etc.
Among these, acrylic resins and polycarbonate resins are particularly desirable from the viewpoint of optical properties and mechanical properties.

In the present invention, there is no particular restriction on the thickness of these transparent substrates, and they may be in the form of a plate or a film. Further, there is no particular restriction on its shape and size, and it may be circular or card-shaped.

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, and these unevenness are made of the thermoplastic resin described above. Molding (injection, compression, etc.)
It is preferable to use a stamper or the like to apply it.

As a method for fixing the recording layer containing the compound used in the present invention on a transparent substrate and forming a thin film, for example, vacuum evaporation method, sputtering method, ion plate method, LB method, etc. can be applied, but these methods are Repetition is complicated,
Moreover, since it is inferior in terms of productivity, a so-called coating method is most preferable.

When forming a recording layer by a coating method, phthalocyanine derivatives can be mixed with common alcohols, ketones, amides, sulfoxides, ethers, esters, aliphatic halogenated hydrocarbons, aromatic hydrocarbons, etc. Apply by dispersing or dissolving in an organic solvent. Also, in some cases,
A polymer adhesive may also be added. As a polymer adhesive,
Vinyl chloride resin, acrylic acid resin, polyester resin,
Preferred are polyethylene resins, polyamide resins, polycarbonate resins, epoxy resins, methacrylic acid resins, vinyl acetate resins, nitrocellulose, polypropylene resins, polyethylene terephthalate resins, phenolic resins, and copolymers thereof.

At that time, the ratio of resin to the compound used in the present invention is 1
It is preferably 0% by weight or less.

The thickness of the recording layer of the present invention formed on the transparent substrate is 10
μm or less, preferably 500 to 2 μm. In addition, by bringing vapor of an organic solvent such as chloroform, tetrahydrofuran, or toluene into contact with the thin film after forming the recording layer, that is, a thin film, the absorption wavelength of the thin film shifts to longer wavelengths, significantly increasing the sensitivity to light oscillated from a semiconductor laser. It may be possible to improve it.

For protection of the recording layer, A I20 y, S i O2,
A protective layer may be provided by depositing an inorganic compound such as 5iO1SnO. Furthermore, various polymers conventionally known for protecting the recording layer may be applied.

Recording on the recording medium is performed by irradiating the recording layer provided on the substrate with laser light, preferably semiconductor laser light, focused to about 1 μm. The portion irradiated with the laser beam absorbs the laser energy and undergoes thermal state changes such as decomposition, evaporation, and melting. The recorded information can be read from the difference in reflectance based on the presence or absence of a state change.

The recording layer of the present invention may be formed by mixing and dispersing or mixing and dissolving other dyes in the compound used in the present invention. Examples of dyes that can be used in combination include known ones, such as aromatic or unsaturated aliphatic diamine metal complexes, aromatic or unsaturated aliphatic dithiol metal complexes, phthalocyanine complexes, naphthalocyanine complexes, squalium dyes,
naph) to quinone complexes, anthraquinone dyes, polymethine dyes, etc.

As a light source, various lasers such as He-Ne laser, Ar laser, and semiconductor laser can be used, but the price and
Semiconductor lasers are particularly preferred in terms of size. As the semiconductor laser, a laser having a center wavelength of 830 nm, 780 parts m, or shorter wavelength is preferable.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Parts in each example indicate parts by weight.

Example 1 After dropping a solution consisting of 3 parts of compound (1) and 100 parts of methyl cellosolve onto an acrylic resin substrate, this substrate was
It was rotated for 20 seconds at a speed of 0.00 rpm.

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 a turntable, and while rotating the turntable at 800 rpm,
Recording was performed by irradiating the recording layer in a track shape with a gallium-aluminum-arsenic semiconductor laser (830 parts m) focused at 5 mW and 8 MHz.

When the surface of this recording medium was observed with a scanning electron microscope, clear bits were observed6.Also, when this recording medium was irradiated with a low-power gallium-aluminum-arsenic semiconductor laser beam and the reflected light was detected, it was put into practical use. A waveform with a sufficient S/N ratio was shown.

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

After dropping this solution onto a Pyrex substrate, the substrate was rotated at 700 rpm. Next, heat this board to 90℃
The mixture was dried for 2 hours to obtain a recording medium.

The thickness of this recording layer was 1000.

When recording was performed on this recording medium in the same manner as in Example 1, clear bits were observed on the surface of the recording layer by scanning electron microscopy. When detecting the reflected light with respect to the incident light using the same method as in Example 1, the S/S was sufficient for practical use.
A waveform with an N ratio was shown.

Example 3 3.5 parts of compound (10) to 100 parts by weight of ethyl cellosolve
This solution was applied onto a polycarbonate resin substrate by a spinner coating method at 60 Orpm, and then dried under reduced pressure at 80 to 90°C for 1 hour to obtain a recording medium with a recording layer thickness of about 900. Ta.

When recording was performed on this recording medium in the same manner as in Example 1, clear bits were observed on the surface of the recording layer by scanning electron microscopy. Further, when the reflected light with respect to the incident laser light was detected in the same manner as in Example 1, a waveform having a practically sufficient S/N ratio was shown.

Example 4 On an acrylic substrate with a thickness of II, a vacuum degree of 10-7 torr was applied.
Compound (8) was vapor-deposited with the substrate temperature at room temperature to obtain a recording medium with a film thickness of approximately 600 mm.

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

Ruhadaza Rikime

Claims (1)

[Claims] In an information recording medium that performs recording by causing a state change by high-density energy irradiation, a 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, and R_1 to R_2_4 each independently represent a hydrogen atom, a halogen atom, a cyano group, or a nitro group. , carboxylic acid group, sulfonic acid group, substituted or unsubstituted aliphatic hydrocarbon group, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, -OR_2_5, -SR_2_6, ▲Formula There are , chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼▲
There are mathematical formulas, chemical formulas, tables, etc. ▼, -NHCOR_3_
3, -CO_2R_3_4, -N=N-R_3_5, R
_3_6(YCH_2CH_2)_lZ-, (where R_2_5 to R_3_6 are a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocarbon group) represents a ring group, Y and Z each independently represent an oxygen atom or a sulfur atom, l represents a positive integer of 1 to 20.), M is a halogen atom, an oxygen atom, ■OR_3_7)_m,
Or ■OSiR_3_8R_3_9R_4_0)_
Represents a metal atom or a hydrogen atom that may have n (here, R_3_7 to R_4_0 are R_1 to R
_2_4 has the same meaning, m and n are both 0,
Represents 1 or 2. )], an optical recording medium comprising a recording layer containing at least one of the following thionaphthalocyanine compounds.