JPH02116592A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain a film material for an optical recording medium having a high sensitivity to a near infrared light, a high solubility in solvent, a high reflectance, no toxicity, and a superior durability by forming an organic film mainly composed of a specific phthalocyanine compound on a substrate. CONSTITUTION:An optical recording medium is formed by providing a film mainly composed of a phthalocyanine compound shown by a general formula (I) on a substrate. The optical recording medium formed by providing the film of the phthalocyanine compound on the substrate meets all of a sensitivity in a near infrared region, a reflectance, and a durability and is effectively used as a recording and regeneration medium using various types of light, such as an optical disk, an optical card, and a tape. As the substrate, a material which is either transmittable or untransmittable to a laser light used can be used, but in the writing with a laser light from a substrate side a laser light- transmittable material must be used. As the substrate material, a glass, an acrylic resin, a methacrylic resin, a polyester resin, a nitrocellulose resin, and a polyamide resin are exemplified.

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 an organic 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 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 laser light to form pits, and recorded information is read out based on the difference in reflectance between the pits and the out-of-focus areas. The structure of the recording layer for recording and reproduction (reading) may be two or more layers consisting of a recording thin film forming layer and a reflective film, but it is advantageous to have only a recording thin film layer that has both of the above functions. be. In the case of a single-layer film for this recording thin film layer, it is necessary that the material of the recording thin film layer itself has a high reflectance in order to obtain a high C/N ratio. As this type of recording medium, inorganic T
E is known to use a low melting point metal of its alloy, and as an organic type, it is known to use a cyanine dye or a phthalocyanine compound.

(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. Organic thin-film optical recording media using cyanine dyes have the advantage of being able to be produced using relatively inexpensive methods such as the spin-coding method, but are not satisfactory in terms of performance, such as storage stability (durability). The current situation is that this state has not been reached. Furthermore, in the case of naphthoquinone and anthraquinone, they have poor solubility in solvents and have storage stability problems such as the formation of agglomerated structures. Furthermore, phthalocyanine compounds are also unsatisfactory due to their solvent solubility, semiconductor laser matching properties, and crystal changes during storage.

(Means for solving the problem) A method for recording and reproducing optical recording media that is highly sensitive to light in the near-infrared region, has high solvent solubility, high reflectance, is nontoxic, and has 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 an organic thin film containing a phthalocyanine compound represented by the following general formula [1] as a main component is formed on a substrate.

(However, in the formula, X may be the same or different, and the substitution positions are limited to the 1.4, 5, 8, 9, 12, 13, and 18 positions, and -Z'-R' -22 zl is -COO-.

-CONR2+, -5o2NR3- An organic group N R' is a linear or branched alkylene group having 1 to 18 carbon atoms, a polyoxyalkylene group, an alkylarylene group or arylene group having 6 to 14 carbon atoms, a carbon Divalent organic group selected from cycloalkylene groups of number 4 or more, Z
2 is halogen, hydrogen, -〇R4, -8R5, -8O2
An organic group selected from NR6R7-NR8R', R4 to R
9 is a straight chain or branched alkyl group having 1 to 18 carbon atoms,
An organic group selected from an alkenyl group, a polyoxyalkyl group, an allyl group, a cycloalkyl group having 4 or more carbon atoms, R2
~R3 represents hydrogen, an organic group selected from a linear or branched alkyl group having 1 to 10 carbon atoms, an alkenyl group, an acyl group, and an alkyl sulfate group; M is hydrogen, a metal, or a metal oxide; It represents a metal halide or a metal hydroxide, n' to n4 each represent a number of 0 to 2, and the total of n1 to n4 is 3 to 8. ) The optical recording medium in which the specific phthalocyanine compound of the present invention is formed as a thin film on a substrate satisfies all of the sensitivity, reflectance, and durability in the near-infrared region, and is suitable for various types of optical discs, optical cards, tapes, etc. It is useful as a medium for recording and reproducing using light.

As long as the object of the present invention is not impaired, the phthalocyanine compound may be used in combination with a stabilizer, a lubricant, an antistatic agent, a polymer compound as a binder, other dyes, and a sensitizer. The substrate material used in the present invention may be transparent or opaque to the laser beam used, but if 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 mlLfi vinyl resin, polyparaphenylene resin, and the like. These resins are shaped like sheets, films, disks, etc.
Moreover, these shaped objects may have an undercoat layer or a layer formed by vapor-depositing a specific metal, if necessary.

Hereinafter, more detailed explanation will be given with reference to Examples.

In addition, the measurement and evaluation of characteristics in Examples were as follows.

A phthalocyanine compound was dissolved in ethanol at a concentration of 1.5%, and a 70 mm thin film was formed on a glass substrate using a spin coater. The absorption and reflection spectra of this were measured using a UV-VIS spectrometer (Shimadzu UV21OA). From this, the reflectance (R%) at 830 nm was determined.

Note U5- The recording medium obtained above was irradiated with an 830 nm semiconductor laser at an optical power of 7 my, with a lens diameter of 1-, and writing was performed in the concave portions of the tracks.

Next, using the same laser light source (0.5 mw) as read light, the write light pulse width at which the C/N ratio of the reflected light was 50 dB or more was determined to be 1ill, and the reciprocal of the sensitivity was calculated.

Salmon = "1 The reflectance and C/N ratio after irradiating the above recording medium at 63° C. for 300 hours using a Cyshine Carbon Arc Fade Meter were measured to examine deterioration.

The recording medium obtained by the recording medium was stored at 70° C. and 90% RH for 3 months, and the reflectance and C/N ratio were measured.

Place 1.5 g of the phthalocyanine compound in a tester with a stopper.
5□Q of ethanol was added, the mixture was sealed tightly and dissolved by applying ultrasound at 60°C for 30 minutes. Next, the mixture was allowed to stand at room temperature for 1 hour, filtered, and the soluble content was measured to determine the solubility.

(Example) A phthalocyanine compound corresponding to each experiment Nα described below was dissolved in ethanol and coated on a glass substrate-L to a solid content thickness of 70 nm using a spin coater. Various characteristics and performances of each of the obtained samples were evaluated. The results are shown in Table-I. In the formula, tBu represents a tertiary-butyl group.

*Examples 1 to 6, Comparative Example 1-3 Example- Example-4 Example-5 Example-2 Example-3 ■, -COO(CH2)2N(C2H5)2 Example-6 Comparative Example- Comparative Example-2 Comparative Example-3 (Effects of the Invention) An optical recording medium in which a thin film containing the specific phthalocyanine compound of the present invention as a main component was formed on a substrate, solubility, reflectance,
It was found that both the reciprocal of the write sensitivity and the read SZN ratio had well-balanced properties required for an optical recording medium, and the medium was also found to be excellent in durability. On the other hand, if a similar phthalocyanine compound is not represented by the general formula of the present invention, it will be inferior in one of the above properties as an optical recording medium and will not be practical. It turned out to be something vague.

Claims (1)

[Claims] (1) An optical recording medium characterized by forming a thin film containing a phthalocyanine compound represented by the following general formula [1] as a main component on a substrate. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, X may be the same or different, and the substitution positions are limited to the 1, 4, 5, 8, 9, 12, 13, and 16 positions. , -Z^1-R^1-Z^2, where Z^1 is -COO-, -CONR^2-, -
An organic group selected from SO_2NR^3-, R^1 is a linear or branched alkylene group having 1 to 18 carbon atoms, a polyoxyalkylene group, an alkylarylene group or arylene group having 6 to 14 carbon atoms, and a carbon number A divalent organic group selected from 4 or more cycloalkylene groups, Z^2 is halogen, hydrogen, -OR^4, -SR^5, -SO_2NR^
An organic group selected from 6R^7, -NR^8R^9, R^
4~R^9 is an organic group selected from a linear or branched alkyl group having 1 to 18 carbon atoms, an alkenyl group, a polyoxyalkyl group, an allyl group, and a cycloalkyl group having 4 or more carbon atoms; R^2~ R^3 represents hydrogen, an organic group selected from a linear or branched alkyl group having 1 to 10 carbon atoms, an alkenyl group, an acyl group, and an alkyl sulfate group, and M represents hydrogen, a metal, or a metal oxide. , metal halide, and metal hydroxide; n^1 to n^4 each represent a number of 0 to 2; and the sum of n^1 to n^4 is 3 to 8. )