JPH0815809B2 - Optical recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides 9,19-dioxadinaphtho- [3,2,1-de: 3,2,1-op] pentacene-5, as an information recording layer. The present invention relates to an optical recording medium having a 15-dione derivative.

More specifically, the present invention relates to an optical recording medium for recording by utilizing the change in the state of matter by the light energy of the oscillation wavelength of a semiconductor laser.

[Conventional technology]

Various types of optical recording media are known as this type of optical recording medium.

For example, JP-A-55-97033 discloses a substrate in which a single layer of a phthalocyanine dye is provided. Phthalocyanine dyes have problems such as low sensitivity, high decomposition point and difficulty in vapor deposition, and also have a problem that solubility in organic solvents is extremely low and they cannot be used for coating by coating. .

Further, JP-A-58-83344 and JP-A-58-224793 disclose a recording layer containing a phenalene dye and a naphthoquinone dye, respectively. However, such dyes have the advantage of being low in reflectivity, while having the advantage of being easily deposited. When the reflectance is low, the contrast relating to the reflectance between the portion recorded by the laser beam and the unrecorded portion is low, and it becomes difficult to reproduce the recorded information. In addition, organic dyes generally have a problem of poor storage stability.

[Problems to be solved by the invention]

INDUSTRIAL APPLICABILITY The present invention provides an optical recording medium using a dye which is easy to deposit, has high solubility in an organic solvent, can be coated by coating, and has high reflectance, good contrast, and excellent storage stability. It is intended to be provided.

[Means for solving problems]

The present invention is an optical recording medium for recording and reproducing by causing a change in state by a laser beam, the substrate having the following dye skeleton: Represented by 9,19-dioxadinaphtho- [3,2,1-de: 3,
The gist of the present invention is an optical recording medium comprising a recording layer containing a 2,1-op] pentacene-5,15-derivative.

Preferably 9,19-dioxadinaphtho- [3,2,1-de: 3,
2,1-op] pentacene-5,15-dione derivative represented by the following general formula [I] (In the formula, R ¹ , R ² , R ³ and R ⁴ represent a hydrogen atom, an alkyl group, an alkoxy group, a halomethyl group and a halogen atom, and R ⁵ ,
R ⁶ represents a hydrogen atom or a halogen atom. ) An optical recording medium comprising a recording layer containing a dye represented by

In the dye represented by the general formula [I] of the present invention, R ¹ ,
The alkyl group represented by R ² , R ³ and R ⁴ is a methyl group,
Ethyl group, a linear or branched propyl group, and C ₁ ~ ₄ alkyl groups such as linear or branched butyl group, the alkoxy group, methoxy group, an ethoxy group,
Linear or branched propoxy group, an alkoxy group of C ₁ ~ ₄ such as linear or branched butoxy group,
Examples of the halogen atom include fluorine atom, bromine atom, chlorine atom and iodine atom, and examples of the halomethyl group include chloromethyl group, bromomethyl group and the like. Also,
The halogen atom represented by R ⁵ and R ⁶ is a fluorine atom,
Examples thereof include a bromine atom, a chlorine atom and an iodine atom.

The dye represented by the general formula [I] has absorption in the wavelength band of 650 to 800 nm and has a molecular absorption coefficient of 10 ⁴ to 10 ⁵ cm.
^-1 .

In the present invention, the dye used is synthesized by a conventional method, for example, Eugen Mller, Otto Bayer; Methoden Der Organi.
schen Chemi (Chinoneteil III) P298 (1979): Nakazawa,
Abe, Takato, Nakayama, Mine; 20th Annual Meeting of the Chemical Society of Japan, 4R222,
P480: Nakazawa, Hirakawa, Watanabe; The 22nd Annual Meeting of the Chemical Society of Japan, 10012, P
2394: Nakazawa, Hirakawa, Yutsudo; It can be easily carried out according to the description of the proceedings of the Joint Fall Conference of the Chemical Society of Japan and Chemical Society, 3E-19, 1969.

The optical recording medium of the present invention basically comprises a substrate and a recording layer. However, if necessary, an undercoat layer may be provided on the substrate and a protective layer may be provided on the recording layer. You can

The substrate in the present invention may be either transparent or opaque to the laser beam used. Examples of the material of the substrate material include a support for a general recording material such as glass, plastic, paper, plate-shaped or foil-shaped metal, and plastic is preferable from various points. Examples of the plastic include acrylic resin, methacrylic resin, vinyl acetate resin, vinyl chloride resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyimide resin, polysulfone resin and the like.

When the dye of the general formula [I] is used as the information recording layer in the optical recording medium of the present invention, the film thickness is 100Å to 5
μm, preferably 1000Å to 3 μm. As a film forming method, a generally used thin film forming method such as a vacuum vapor deposition method, a sputtering method, a doctor blade method, a cast method, a spinner method and a dipping method can be used.

As a coating solvent for forming the recording layer by a coating method such as a doctor blade method, a cast method, a spinner method, a dipping method, or a spinner method, bromoform, dibromoethane, tetrachloroethane, ethyl cellosolve, xylene, chlorobenzene, cyclohexanone Boiling point of 120
Those having a temperature of up to 180 ° C are preferably used.

In the case of film formation by the spinner method, the rotation speed is 500 to 5
000 rpm is preferable, and after spin coating, in some cases, a treatment such as heating or exposure to solvent vapor may be performed.

Further, a binder can be used if necessary. PVA, PVP, nitrocellulose,
Known materials such as cellulose acetate, polyvinyl butyral, and polycarbonate are used, and the amount of the dye with respect to the resin is preferably 0.01 or more in weight ratio.

In order to improve the stability and light resistance of the recording medium, a transition metal chelate compound (for example, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α) is used as a singlet oxygen quencher.
-Diketone and the like). Further, other dyes can be used in combination, if necessary. The other dye may be a different type of dye of the same system, or may be a dye of another system such as a triarylmethane dye, an azo dye, a cyanine dye, and a squarylium dye.

The recording layer of the optical recording medium of the present invention may be provided on both sides of the substrate, or may be provided on only one side.

Recording on the recording medium obtained as described above is performed by irradiating a recording layer provided on both sides or one side of the substrate with a laser beam focused with a beam diameter of about 1 μm, preferably a semiconductor laser beam. In the portion irradiated with laser light, thermal deformation of the recording layer such as decomposition, evaporation, and melting occurs due to absorption of laser energy.

The recorded information is reproduced by using a laser beam to read the difference in reflectance between a portion where thermal deformation has occurred and a portion where thermal deformation has not occurred.

The laser light used for the optical recording medium of the present invention is preferably a semiconductor laser from the viewpoints of light weight, easy handling, compactness and the like.

EXAMPLES The present invention will be specifically described below with reference to examples, but the examples do not limit the present invention.

Example 1 A dye represented by the following structural formula was heated to about 80 to 150 ° C. under a vacuum of 1.6 × 10 ⁻⁵ Torr and vacuum was applied on a methacrylic resin (hereinafter referred to as PMMA) substrate having a thickness of 1.2 mm. It was vapor-deposited. The vapor deposition film thickness was 600Å as a result of the vacuum vapor deposition film thickness measurement by the crystal vibration type film thickness meter. The maximum absorption wavelength by the spectrophotometer is 700 nm and the reflectance is 30% at 830 nm. The shape of the spectrum was wide.

When a semiconductor laser with a central wavelength of 780 nm was used as a light source on the thin film thus obtained and writing was performed with a beam diameter of about 1 μm, uniform and clear pits were obtained, and the carrier level / noise level was obtained. Ratio (C / N
The ratio) was also good.

In addition, this recording medium has a temperature of 60 ° C and a humidity of 90 at room light.
It showed good storability under the condition of%.

Example 2 The compounds shown in Table 1 below were used in place of the dyes used in Example 1 and vacuum-deposited in the same manner as in Example 1 to obtain the maximum absorption wavelengths shown in Table 1 below. A thin film substrate having When a semiconductor laser was used as a light source for writing on the thin film thus obtained, uniform and clear pits were obtained. C / N
The ratio was also good and the storage stability was good.

Example 3 0.5 g of the dye represented by the following structural formula was dissolved in 50 g of tetrachloroethane and passed through a 0.22 μ filter to obtain a solution. 2 ml of this solution was added to a PMMA resin substrate (120 m) with 700 Å depth and 0.7 μm width UV-curing resin with grooves (groups).
mφ) and was applied by a spinner method at a rotation speed of 500 rpm. After coating, it was dried at 60 ° C. for 10 minutes. When it was applied to a glass plate under the same conditions and the film thickness was measured by a Taris step, it was 750Å. The maximum absorption wavelength of the coating film measured by the spectrophotometer was 705 nm, and the reflectance was 26% (830 nm). The shape of the spectrum was wide. Figure 1 shows the absorption and reflection spectra.

When this coating film was irradiated with a semiconductor laser beam having a central wavelength of 780 nm at an output of 6 mW and a beam diameter of 1 μm, the width was about 1 μm.
An extremely clear pit having a pit length of about 2 μm was formed. The C / N ratio was high and the storage stability (60 ℃, 80% RH) was good.

Example 4 When the compounds shown in Table 2 below were used instead of the dyes used in Example 3 and coating was carried out by a method similar to that described in Example 3, the maximum absorption wavelength shown in Table 2 below was obtained. A thin film substrate having When a semiconductor laser was used as a light source for writing on the thin film thus obtained, uniform and clear pits were obtained. C / N
The ratio was also good and the storage stability was good.

(Effects of the Invention) According to the present invention, the dye is easy to deposit, has high solubility in an organic solvent, can be coated by coating, has high reflectance, has good contrast, and has excellent storage stability. 9,19-Dioxadinaphtho- (3,2,1-de:
An optical recording medium using a 3,2,1-op] pentacene-5,15-dione derivative can be obtained.

[Brief description of drawings]

FIG. 1 shows absorption and reflection spectra by a spectrophotometer of a coating film of Example 3 which is an example of the dye of the present invention. The vertical axis indicates absorbance and the horizontal axis indicates wavelength.

Claims (2)

[Claims] 1. An optical recording medium for recording / reproducing by causing a change in state by a laser beam, the substrate having the following dye skeleton: Represented by 9,19-dioxadinaphtho- [3,2,1-de: 3,
An optical recording medium comprising a recording layer containing a 2,1-op] bentacene-5,15-dione derivative. 2. A 19,19-dioxadinaphtho- [3,2,1-de: 3,
The 2,1-op] pentacene-5,15-dione derivative has the following general formula: (In the formula, R ¹ , R ² , R ³ and R ⁴ represent a hydrogen atom, an alkyl group, an alkoxy group, a halomethyl group and a halogen atom, and R ⁵ ,
R ⁶ represents a hydrogen atom or a halogen atom. The optical recording medium according to claim 1, which is a dye represented by