JPS63242588A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium having high sensitivity to light in a near infrared region, high solubility in solvents, high reflectance, no toxicity and excellent durability, by providing an organic thin film comprising a phthalocyanine compound and a cyanine compound on a substrate. CONSTITUTION:An organic thin film comprising a phthalocyanine compound and a cyanine compound is provided on a substrate. The phthalocyanine compound is preferably one represented by formula I. The cyanine compound is preferably one represented by formula II. Preferably, 5-90wt.% of the phthalocyanine compound and 95-10wt.% of the cyanine compound are mixed with each other, whereby an optical recording medium can be obtained which has high sensitivity to light in a near infrared region, high reflectance, excellent weatherability and excellent solubility in solvents, and is advantageous for production. In the formulas, each of m1-m4 and n1-n4 is the number of linked groups P or Q, each of the linked groups being an amino acid, substd. amino, imino, nitro or the like, each of R<1>-R<3> is a 1-6C alkyl, X is a halogen, a perhalogen acid or the like, and each of A<1> and A<2> is a benzene ring or naphthyl ring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical recording medium, particularly an optical recording medium having a q-system recording layer for a semiconductor laser having absorption in the near-infrared region.

(Prior Art) In recent years, the development of semiconductor lasers has been remarkable, and small and stable oscillators have become available at low cost and have begun to be used as light sources for various recording devices. However, the wavelengths of these semiconductor lasers are limited to relatively long wavelengths, and semiconductor lasers capable of oscillating short wavelength light have problems in terms of lifespan, output, etc. Therefore, as a recording medium for a semiconductor laser, it is essential to use a material that absorbs in the near-infrared region as a thin film layer, and a material with a maximum absorption wavelength of 750 μm or less is inappropriate. Conventionally, as this type of recording medium, there is one in which a thin film formed on a substrate is irradiated with a laser beam to form bits, and recorded information is read out based on the difference in reflectance between the bits and the non-bit parts. This recording and playback (
The recording color configuration for readout may be two or more layers consisting of the recording thin film formation order and the reflective film, but it is advantageous to have only the recording thin film layer having both of the above functions. This recording thin film layer has a single I! In the case of J film, it is necessary that the material of the recording thin film layer itself has a high reflectance in order to obtain a high S/N ratio. As this type of recording medium, inorganic ones using low melting point metals such as Te or alloys thereof are known, and organic ones using cyanine dyes and phthalocyanine compounds are known.

(Problems to be solved by the invention) Inorganic optical recording media using Te-based alloys have relatively high sensitivity, but they have problems with toxicity, and the film formation method uses sputtering, etc., so equipment costs are high. However, it also has the disadvantage of low productivity.In the case of organic thin film optical recording media using cyanine dyes, it has the advantage of being able to be produced using relatively inexpensive methods such as spin coding. Currently, however, they have not reached a state that is satisfactory in terms of performance, such as storage stability (durability). Also, in the case of naphthoquinone and anthraquinone, they have poor solvent solubility, and the formation of agglomerated structures makes storage difficult. There were problems with stability.Furthermore, in the case of phthalocyanine compounds, they were unsatisfactory due to solvent solubility, semiconductor laser matching properties, crystal changes during storage, etc.

(Means for solving the problem) For recording and reproduction of optical recording media that are highly sensitive to light in the near-infrared region, have high solvent solubility, high reflectance, are non-toxic, and have excellent durability. In order to provide a thin film material and thereby an excellent optical recording medium, the present invention was arrived at as a result of intensive studies.

That is, the present invention is an optical recording medium characterized in that a thin film containing a phthalocyanine compound and a cyanine compound is formed on a substrate, and the phthalocyanine compound is represented by the following formula (I). Phthalocyanine compounds represented by are preferred.

In the margins below (formula CI), numbers 1 to 16 indicate the positions of surrounding carbon atoms a mr , ms tm3, m4
represents the number of bonding groups represented by P, which may be the same or different, and each is an integer from 0 to 4. rl++nm, ns, and na represent the number of bonding groups represented by Q, which may be the same or different types, and each is an integer of O to 4. Two or more of the peripheral carbon atoms represented by 1 to 16 are substituted with a bonding group represented by P, and the bonding group is an amino group, a substituted amino group, an imino group, a nitro group, a cyano group, a sulfonic acid group. group, sulfonic acid group, sulfonyl group, hydroxyl group, or halogen, and 3 to 8 of the surrounding carbon atoms represented by 1 to 16 are Q
is substituted with a bonding group represented by, Q is represented by (Z)rR, and 2 is -CH, -1-Q-, -C
Indicates either ONH-1-COO-, R has 4 carbon atoms
~18 linear or branched alkyl or allyl groups.

M represents hydrogen metal, metal oxide, metal hydroxide, or metal halide, and r is O or the number 1.

) Moreover, as the cyanine compound in the present invention, a cyanine compound represented by the following formula CII) is preferable.

(However, in formula (Il), n represents O or an integer from 1 to 3, R'rR" + R' may be the same or different and each represents an alkyl group having 1 to 6 carbon atoms, and X represents a halogen , perhalogen acid, boron tetrafluoride,
Indicates either toluenesulfonic acid or alkyl sulfuric acid,
A'+A'' represents a benzene ring or a naphthyl ring, and each ring may be substituted with any one of an alkyl group, an alkoxy group, a hydroxy group, a carboxy group, a halogen, an allyl group, and an alkyl carboxyl group. ) In formula CI), when the number of substituents P is less than 2,
Or, when the number of substituents Q is 9 or more, or when the number of carbon atoms in R is greater than 19, the near-infrared sensitivity and reflectance decrease, and when the number of substituents Q is not more than 3, or when R When the number of carbon atoms is less than 4, the solvent solubility is insufficient. M is hydrogen, a metal, or a metal compound, and many metals that can form a complex with phthalocyanine are applicable, especially Cu, Mg, Zn, A Q N Ga
11 nl-8nz P bs T r, Vs Cr,
Mn, Fe1Co, and Nl are preferred.

In formula (II), when n is 4 or more, the light resistance and heat resistance as a recording medium are low, making it unsuitable. Furthermore, if the number of carbon atoms in the R1-R3 substituent is 7 or more, the near-infrared sensitivity and reflectance will be low (and it is not suitable for use). By using thin films as optical recording media,
The advantages of cyanine compounds are high sensitivity, high reflectance, and high solubility in solvents, and the disadvantages of poor weather resistance, and the advantages of phthalocyanine compounds, which are excellent weather resistance and disadvantages of low reflectance, are overcome. This makes it possible to obtain an optical recording medium using an organic thin film with balanced quality while maintaining the advantages. In particular, the present invention has discovered, by selecting a specific compound from cyanine compounds and phthalocyanine compounds, an excellent mixture system that cannot be imagined from a simple three-way mixture. It is. The phthalocyanine compound and the cyanine compound are preferably mixed at a ratio of 5 to 90% by weight of the phthalocyanine compound and 95 to 10% by weight of the cyanine compound,
An optical recording medium can be obtained that has excellent sensitivity in the near-infrared region, high reflectance, and weather resistance, and also has excellent solvent solubility and is advantageous in production. More preferably, the weight ratio of the phthalocyanine compound to the cyanine compound is 80/20 to 20/80.
and particularly preferably 75/25 to 25/75.

The optical recording medium of the present invention is one in which a mixture of a phthalocyanine compound and a cyanine compound is formed as a thin film on a substrate. A stabilizer, a lubricant, an antistatic agent, a polymer compound as a binder, other dyes, and a sensitizer may be used in combination. The substrate material used in the present invention may be transparent or opaque to the laser beam used, but when writing and recording is performed using the laser beam from the substrate side, it must be transparent to the laser beam. Examples of these substrate materials include glass, acrylic resin, methacrylic resin, polyester resin, nitrocellulose resin, polyamide resin, polycarbonate resin, polymethylpentene-1 resin, epoxy resin, vinyl chloride resin, polyparaphenylene resin, etc. . These resins are
They are shaped objects such as sheets, films, discs, etc., and these shaped objects may have an undercoat or a layer coated with a specific metal by vapor deposition, if necessary.

Hereinafter, the present invention will be explained in more detail with reference to Examples. The characteristics in the examples were measured and evaluated as follows.

[Measurement of solubility]

Add 250 g of cyanine compound and 5 g of dichloroethane to a test tube with a stopper and dissolve at room temperature. After all the cyanine compounds were dissolved, 1 g of phthalocyanine compound was added to this solution, and the solution was sealed and dissolved by applying ultrasonic waves at 50° C. for 30 minutes. Next, the mixture was left at room temperature for 1 hour, cooled to 25°C, filtered, and the soluble content was measured to determine solubility.

[Absorption spectrum and reflectance]

A mixture of a phthalocyanine compound and a cyanine compound at a predetermined mixing ratio was dissolved in dichloroethane at a concentration of 1.5% by weight, and a thin film having a solid content thickness of 70 nm was formed on a glass substrate using a spin coater. This is UV-VIS
Absorption and reflection spectra were measured using a Me-9- (Shimadzu UV21 OA).

From this, the maximum absorption wavelength (λmax) and the reflectance at 830 nm (R%) were determined.

[Recording characteristics]

The thin film on the substrate obtained in the same manner as described in the section of "Absorption spectrum and reflectance" was irradiated with 830 nm semiconductor laser light with an optical power of 10 m'W and a lens diameter of 1 μm, and writing was performed. Ta.

Next, using the same laser light source (0.2 mW) as read light, the write light pulse width at which the S/N ratio of the reflected light was 50 dB or more was measured, and the reciprocal of the sensitivity was calculated.

〔durability〕

Each thin film on a substrate obtained in the same manner as described in the section “Absorption spectrum and reflectance” was heated at 70°C and 80%RH.
The sample was stored for 3 months under this environment, and its reflectance and SIN ratio were then measured and compared with the respective values before being stored under this environment.

(Examples) [Examples 1 to 7, Comparative Examples 1 to 5] Various phthalocyanine compounds and cyanine compounds shown in Table I were mixed in a predetermined ratio, then dissolved in dichloroethane, and coated on a glass substrate with a 70 nm layer using a spin coater. A thin film was formed by coating to a solid content thickness of , and various properties and performance were measured. The results are shown in Table-■.

In addition, the abbreviations in the table are shown below.

Abbreviations of alkyl groups: Me: methyl group, Et: ethyl group, Bu: t-butyl group, Am: t-amyl group, )le: hexyl group, Hp:
Heptyl group, Dd nidodecyl group and below Margin table - ■ Note 1) Solubility is the value of phthalocyanine compound 2) Table - ■,
In Table 1, m indicates the sum of fTb, m*, m3%m4, and 1n indicates the sum of n+1n, 1n3s n<.

[Examples 8-10. Comparative Examples 6 to 7 The phthalocyanine compounds and cyanine compounds shown in Table 1 were mixed at a predetermined ratio, then dissolved in dichloroethane, and coated on a glass substrate with a spin coater to a solid content thickness of 70 nm to form a thin film. Characteristics and performance were measured. The results are shown in Table ■.

Margin Table -■ (Effects of the Invention) According to the present invention, it is possible to obtain an optical recording medium that incorporates the advantages of phthalocyanine compounds and cyanine compounds while compensating for their disadvantages. Furthermore, by selecting a large number of recompounds and their ratios, it is possible to arbitrarily create optical recording media according to the characteristics.

Claims (3)

[Claims] (1) An optical recording medium characterized in that an organic thin film containing a phthalocyanine compound and a cyanine compound is formed on a substrate. (2) The optical recording medium according to claim 1, wherein the phthalocyanine compound is a phthalocyanine compound represented by the following formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・〔I
] (However, in formula [I], the numbers 1 to 16 indicate the positions of surrounding carbon atoms. m_1, m_2, m_3, m
_4 indicates the number of bonding groups represented by P, which may be the same or different, and each is an integer from 0 to 4. n_1, n_2, n_3
, n_4 represents the number of bonding groups represented by Q, which may be the same or different, and each is an integer from 0 to 4. Two or more of the peripheral carbon atoms represented by 1 to 16 are substituted with a bonding group represented by P, and the bonding group is an amino group, a substituted amino group, an imino group, a nitro group, a cyano group, a sulfonic acid group. group, sulfonic acid group, sulfonyl group, hydroxyl group, or halogen, and 3 of the surrounding carbon atoms shown from 1 to 16
~8 are substituted with a bonding group represented by Q, and Q is (
Z) is represented by rR, and Z is -CH_2-,
-O-, -CONH-, -COO-,
R represents a straight or branched alkyl group or allyl group having 4 to 18 carbon atoms. M represents hydrogen metal, metal oxide, metal hydroxide, or metal halide, and r is a number of 0 or 1. ) (3) The optical recording medium according to claim 1, wherein the cyanine compound is a cyanine compound represented by the following formula [II]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[II] (However, in formula [II], n represents 0 or an integer from 1 to 3, and R^1, R^2, and R^3 are the same. Each represents an alkyl group having 1 to 6 carbon atoms, X represents halogen, perhalogen acid, boron tetrafluoride, toluenesulfonic acid, or alkyl sulfate,
^1 and A^2 represent a benzene ring or a naphthyl ring, and each ring is an alkyl group, an alkoxy group, a hydroxy group,
Indicates that it may be substituted with any one of a carboxyl group, halogen, allyl group, and alkylcarboxyl group. )