JP2507795B2 - Optical recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an optical recording medium capable of writing and reading information by a laser beam.

(Prior Art) Conventionally, various types of optical recording media are known for recording and reading information using a laser beam. One of them is to irradiate the recording layer on the substrate with a laser beam,
Some recording is performed by causing changes such as melting, evaporation, and decomposition in the irradiated area.

As the recording layer of such an optical recording medium, As, Te, Se,
Thin film layers of metals and alloys such as Ti have been used. An optical recording medium having a thin film layer of these metals or alloys as a recording layer is generally characterized by high writing sensitivity and application of a semiconductor laser capable of downsizing a recording / reproducing optical system, but has a large thermal conductivity. For some reason, the energy of the laser beam cannot be used efficiently during recording. In addition, these recording layers are chemically unstable and may deteriorate.

Therefore, JP-A-57-82093, JP-A-58-56892, JP-A-60-89842, JP-A-60-150243, JP-A-61-177287, and JP-A-61-177287 Sho 61-25886 bulletin,
U.S. Pat. No. 4,492,750 has proposed an optical recording medium in which an organic thin film layer is used as a recording layer and information is written or read by a laser beam having a relatively long wavelength, for example, 780 nm or more. In such an optical recording medium, although minute recesses (bits) can be easily formed in the organic thin film layer by melting, evaporation, or decomposition with a semiconductor laser capable of miniaturizing the recording / reproducing optical system, It has drawbacks such as a low absorption coefficient for laser light and insufficient recording sensitivity.

(Problems to be Solved by the Invention) The present invention improves various drawbacks of the conventional optical recording medium having an organic thin film recording layer, is chemically and physically stable, and can record and reproduce with high sensitivity by a laser beam. it can. An optical recording medium using a specific naphthalocyanine compound is provided.

[Structure of Invention]

(Means for Solving the Problems) The present invention is an optical recording medium in which an organic thin film layer containing at least one kind of naphthalocyanine compound represented by the following general formula [I] is provided on a substrate. .

General formula [I] [In the formula, M represents Al, Ga, In, Si, Ge, or Sn.

X may be the same as or different from each other, and may be an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic residue which may have a substituent. , Halogen atom, nitro group, cyano group, sulfonic acid group, -OR
¹ , -SR ² , -COOR ³ , -NR ⁴ R ⁵ , -SO ₂ NR ⁶ R ⁷ , -CONR
⁸ R ⁹ , -CH ₂ NHCOCH ₂ NR ¹⁰ R ¹¹ , -NHCOR ¹² , -N = NR ¹³ ,
Alternatively, it represents -N = CHR ¹⁴ .

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are
Hydrogen atoms, which may be the same or different from each other,
Represents an alkyl group, an aryl group, an acyl group, a cycloalkyl group, or a polyether group which may have a substituent, or R ⁶ and R ⁷ , R ⁸ and R ⁹ , or R ¹⁰
And R ¹¹ may form a 4- to 7-membered ring, and these 4- to 7-membered ring may be a heterocycle containing a hetero atom such as a nitrogen atom.

R ¹² , R ¹³ and R ^{14, which} may be the same or different, each represents an alkyl group having a substituent, a cycloalkyl group or an aryl group.

Y is -OSR ¹⁵ , Represents

Z is a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group which may have a substituent, -OSR ¹⁸ , Represents

R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ , and R ²⁰ may be the same or different from each other and may have a substituent, such as an alkyl group, an aryl group, an acyl group or a cyclo group. It represents an alkyl group, an alkoxy group, an allyloxy group, a polyether group, a hydroxyl group, or a halogen atom.

 W represents O, S, Se, or Te.

 k, l, m, and n each independently represent an integer of 0-8.

p represents 0 or 1. In the naphthalocyanine compound represented by the general formula [I] according to the present invention, typical examples of the atoms and groups forming X, Z, and R ¹ to R ²⁰ include halogen atoms such as chlorine atom and bromine atom. , Iodine atom, and fluorine atom, as the alkyl group which may have a substituent, methyl group, n-butyl group, tert-butyl group, stearyl group, trichloromethyl group, 2-methoxyethyl group, etc. As the aryl group which may have a substituent, a phenyl group, chlorophenyl group, toluyl group, naphthyl group, anthryl group, dimethylaminophenyl group, hydroxyphenyl group, diethylaminonaphthyl group, hydroxynaphthyl group, etc. Examples of the group include a cyclohexyl group and cyclobutyl group, and examples of the acyl group which may have a substituent include an acetyl group and a tol group. Lifluoroacetyl groups, etc., polyether groups such as diethylene glycol monoethyl group, triethylene glycol monobutyl group, etc., and heterocyclic groups such as pyridyl group, furyl group, thiazolyl group, piperazinyl group, morpholyl group, etc. Can be mentioned, but is not limited to these atoms and groups.

In the present invention, the compound represented by the general formula [I] is
For example, it can be manufactured by the following method.

That is, from the isoindolenin compound represented by the following general formula [II] and various metal salts, or by a conventional method using carboxylic acid anhydrides, imides, or nitriles as starting materials, The indicated naphthalocyanine compound is prepared.

General formula (II) [In the formula, X, k, l, m, and n have the same meanings as in the general formula [I]. ] General formula [III] [In the formula, M, X, k, l, m, n and p have the same meanings as in the general formula [I]. Next, the naphthalocyanine compound represented by the general formula [I] can be produced by reacting the obtained naphthalocyanine compound represented by the general formula [III] with various sulfur compounds.

Typical examples of the naphthalocyanine compound represented by the general formula [I] used in the present invention include the following naphthalocyanine compounds (a) to (i).

The substrate used in the present invention preferably has a light transmittance for writing or reading a signal of 85% or more and a small optical anisotropy. For example, heat of glass or alkule resin, polycarbonate resin, polyester resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, polystyrene resin, polyolefin resin (poly-4-methylpentene etc.), polyether sulfone resin, etc. Substrates made of thermosetting resins such as plastic resins, epoxy resins, and allyl resins are examples. Of these, those made of thermoplastic resin are preferable because of their ease of molding and the ease of providing guide grooves and address signals, and those made of acrylic resin or polycarbonate resin because of their optical and mechanical properties. Is especially desirable.

In the present invention, the thickness of these transparent substrates is not particularly limited and may be plate-like or film-like. The shape thereof may be circular or card-like, and the size thereof is not particularly limited.

Further, the substrate usually has guide grooves for position control during recording and reading and unevenness for preformatting such as address signals and various marks. These unevenness are formed by the thermoplastic resin as described above. It is preferable to use a stamper or the like when molding (injection molding, compression molding, etc.).

In the optical recording medium of the present invention, as a method of forming an organic layer thin film layer containing a naphthalocyanine-based compound on a substrate, a vacuum deposition method, a sputtering method, an ion plate method, an LB method (Langmuir-Blodgett method) or the like can be used. There are methods, but these methods are complicated in operation,
The productivity is low, and the central metal represented by the general formula [I] contains at least one -OSR ²¹ , [Wherein R ²¹ is R ¹⁵ or R ¹⁸ in the general formula [I], and
²² is R ¹⁶ or R ¹⁹ in the general formula [I], and R ²³
Represents the same meaning as R ¹⁷ or R ²⁰ in the general formula [I]. The naphthalocyanine-based compound having a group represented by is much more soluble in ordinary organic solvents than organic dyes used in optical recording media having a conventional organic thin film layer. The coating method used is most advantageous. When an organic thin film layer which is a recording layer is formed by a coating method, a naphthalocyanine compound is used as an alcohol, a ketone, an amide, a sulfoxide, an ether, an ester, an aliphatic halogenated hydrocarbon, an aromatic compound. It is applied after being dispersed or dissolved in an ordinary organic solvent such as hydrocarbons. At this time, a polymer binder may be added if necessary. Examples of the polymer binder include vinyl chloride resin, acrylic resin, polyester resin, polyamide resin, polycarbonate resin, epoxy resin, methacryl resin, vinyl acetate resin, nitrocellulose, and phenol resin. When the polymer binder is used, the ratio of the polymer binder to the naphthalocyanine compound is preferably 10% by weight or less.

Further, in the present invention, other dyes may be mixed and dispersed or mixed and dissolved in the naphthalocyanine compound to be used. Examples of dyes that can be mixed and used include known aromatic or unsaturated aliphatic diamine-based metal complexes, aromatic or unsaturated aliphatic dithiol-based metal complexes, phthalocyanine-based complexes, naphthalocyanine-based complexes, and squarylium-based dyes. , Naphthoquinone-based complexes, anthraquinone-based dyes and polymethine-based dyes.

The thickness of the recording layer containing the naphthalocyanine compound formed on the substrate is 10 μm or less, preferably 500 Å to 2 μm.
m. Also, after coating, by exposing to vapor of an organic solvent such as chloroform, tetrahydrofuran, or toluene, the absorption wavelength of the organic thin film layer shifts to the long wavelength side, and the sensitivity of the semiconductor laser to light in the oscillation wavelength range is significantly improved. Sometimes you can.

In addition, in order to protect these recording layers, Al ₂ O ₃ , SiO
An inorganic compound such as ₂ , SiO or SnO may be vapor-deposited to form a protective layer. Further, a polymer may be applied as the protective layer.

Recording on the recording medium obtained as described above is performed by using a laser beam focused to about 1 μm on the recording layer provided on the substrate,
It is preferably performed by irradiating a semiconductor laser beam. The portion of the recording layer irradiated with laser light undergoes thermal state changes such as decomposition, evaporation, and melting due to absorption of laser energy. The reproduction is performed by reading the difference in reflectance between the portion where the thermal change is generated and the portion where the thermal change is not generated. The naphthalocyanine compound represented by the general formula [I] is extremely advantageous as compared with an organic dye used in an optical recording medium having a conventional organic thin film layer because the difference in reflectance before and after recording is extremely large. .

He-Ne laser, Ar laser,
Various lasers such as a semiconductor laser can be used, but the semiconductor laser is particularly preferable in terms of price and size. Lasers with central wavelengths of 830 nm and 780 nm and shorter wavelengths can be used as the semiconductor laser.

〔Example〕

Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples. In the examples, “part” means “part by weight”.

Production Example 1: Production of naphthalocyanine compounds (a) to (d) 50 parts of quinoline and 1,3-diiminobenzisoindoline
Add 7.8 parts and 5.0 parts of silicon tetrachloride, and add 3 at 180-200 ℃.
After heating and stirring for an hour, the mixture was cooled, diluted with 500 parts of methanol, filtered, washed with methanol and dimethylformamide, and dried to obtain 7.0 parts of dihydroxysilicon naphthalocyanine.

Obtained dihydroxysilicon naphthalocyanine 5.0
Parts, triphenylmethanesulfenyl chloride 50 parts, tri-n-butylamine 50 parts, and pyridine 300 parts 110 parts
After heating and stirring at 2 ° C. for 2 hours, the mixture was cooled, diluted with 1000 parts of methanol and filtered to obtain a filtrate, and methanol was distilled off from the obtained filtrate under reduced pressure.

The total amount of the obtained product was poured into 500 parts of dilute hydrochloric acid, and the deposited precipitate was filtered, washed with water, and dried at 80 ° C. to obtain 3.0 parts of naphthalocyanine compound (a).

The naphthalocyanine compounds (b) to (d) were obtained by a method similar to the method for producing the naphthalocyanine compound (a).

Production Example 2: Production of Naphthalocyanine Compounds (e) to (i) Dihydroxysilicon naphthalocyanine 5.0 parts, p-toluenesulfonyl chloride 50 parts, tri-n-butylamine 50 parts, and pyridine 300 parts at 110 ° C. for 2 hours. After heating and stirring, cool, dilute with 1000 parts of methanol, filter,
A filtrate was obtained, and methanol was distilled off from the obtained filtrate by heating under reduced pressure.

The total amount of the obtained product was poured into 500 parts of diluted salt, and the deposited precipitate was filtered, washed with water, and dried at 80 ° C. to obtain 2.5 parts of naphthalocyanine compound (e).

The naphthalocyanine compounds (f) to (i) were obtained by a method similar to the method for producing the naphthalocyanine compound (e).

Example 1. A naphthalocyanine compound (a) was formed on a glass substrate.
A solution consisting of 3.0 parts and 97.0 parts of chloroform was added dropwise, followed by rotation at 1200 rpm for 20 seconds and drying at 80 ° C for 20 minutes to obtain an optical recording medium. The obtained optical recording medium is
The thickness of the recording layer was 780Å, the maximum absorption wavelength was 805 nm, and the reflectance for light with a wavelength of 830 nm was 43%.

The obtained optical recording medium was mounted on a turntable, and while rotating the turntable at 1800 rpm, 1.0 μ
Recording was performed by irradiating a 830 nm laser beam focused on m at 5.0 mW and 8.0 MHz.

When the surface of the optical recording medium after recording was observed with a scanning electron microscope, clear pit formation was observed. Moreover, when the obtained optical recording medium was irradiated with laser light of 830 nm and 0.4 mW and the reflected light was detected, the C / N ratio was 53 dB.
Met.

Example 2. After dropping a solution of 2.5 parts of naphthalocyanine compound (e) and 97.5 parts of methyl cellosolve onto a polycarbonate resin substrate, the solution was rotated at a speed of 800 rpm for 30 seconds, and the pressure was reduced to 80 ° C. for 15 minutes. An optical recording medium was obtained by drying.

The obtained optical recording medium has a recording layer thickness of 850Å, a maximum absorption wavelength of 800 nm, and a reflectance of 40% for light with a wavelength of 830 nm.
Met.

When recording was performed on the obtained optical recording medium in the same manner as in Example 1, a clear pit shape was recognized on the surface of the recording layer, and the C / N ratio was 51 dB.

Examples 3 to 9. In the same manner as in Example 1, naphthalocyanine compounds (b) to (d) and (f) to (i) were formed on a glass substrate.
Was applied and dried to obtain an optical recording medium.

The maximum absorption wavelength and reflectance of light having a wavelength of 830 nm of the recording layer of the obtained optical recording medium, and C / when recording / reproducing was performed on the obtained optical recording medium in the same manner as in Example 1.
The N ratio is shown in Table 1.

[Effects of the Invention] Since the naphthalocyanine compound used in the optical recording medium of the present invention has extremely high solubility in the above-mentioned ordinary organic solvents, it is possible to dissolve it in these organic solvents to improve productivity and workability. It can be provided as an organic thin film layer on a substrate by a coating method having good properties, and the optical recording medium of the present invention has a very large difference in reflectance before and after recording by a laser beam, so that the sensitivity is high and recording / reproducing with high sensitivity is possible. It is also chemically and physically stable.

Claims (1)

(57) [Claims] 1. An optical recording medium comprising a substrate and an organic thin film layer containing at least one naphthalocyanine compound represented by the following general formula [I]. General formula [I] [In the formula, M represents Al, Ga, In, Si, Ge, or Sn. X's may be the same or different from each other, and may have an alkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic residue which may have a substituent, Halogen atom, nitro group, cyano group, sulfonic acid group, -OR ¹ , -S
R ² , -COOR ³ , -NR ⁴ R ⁵ , -SO ₂ NR ⁶ R ⁷ , -CONR ⁸ R ⁹ , -CH ₂
NHCOCH ₂ NR ¹⁰ R ¹¹ , -NHCOR ¹² , -N = NR ¹³ , or -N
= Represents CHR ¹⁴ . R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ may be the same or different from each other and have a hydrogen atom or a substituent. Represents an alkyl group, an aryl group, an acyl group, a cycloalkyl group, or a polyether group which may be substituted, or R ⁶ and R ⁷ , R ⁸ and R ⁹ , or R ¹⁰ and R
¹¹ and ¹¹ may form a 4- to 7-membered ring.
The 7-membered ring may be a heterocycle containing a hetero atom such as a nitrogen atom. R ¹² , R ¹³ and R ^{14, which} may be the same or different, each represents an alkyl group having a substituent, a cycloalkyl group or an aryl group. Y is -OSR ¹⁵ , Represents Z is a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group which may have a substituent, -OSR ¹⁸ , Represents R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ , and R ²⁰ may be the same or different from each other and may have a substituent, such as an alkyl group, an aryl group, an acyl group or a cyclo group. Alkyl group,
Represents an alkoxy group, an allyloxy group, a polyether group, a hydroxyl group, or a halogen atom. W represents O, S, Se, or Te. k, l, m, and n each independently represent an integer of 0-8. p represents 0 or 1. ]