JPS63120686A - Optical recording medium - Google Patents

Abstract

PURPOSE:To enable writing to be performed with low power and prevent a reflectance from being lowered, by using a resin material in which at least one of tocopherol and derivatives thereof is dispersed together with a reduced product of a dithiolate complex. CONSTITUTION:A reduced product 6 of a dithiolate complex and at least one 7 of tocopherol and derivatives thereof are dispersed in a resin material 31 for constituting a lightabsorbing layer. The tocopherol and the derivatives thereof include alpha-tocopherol. The reduced product of a dithiolate complex may be a reduced product of bis-1-4-dimethylaminophenyl-2-phenylethanedithionnickel (OBDN) or the like. An optical recording medium 1 can be obtained by applying a resin material, which is obtained by dispersing at least one 7 of tocopherol and derivatives thereof and the reduced product 6 of a dithiolate complex in a resin 31, to a base 2 such as a glass, a quartz plate and a plastic, followed by drying.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to an optical recording medium used in, for example, an optical disk recording and reproducing apparatus.

[Conventional technology]

Conventionally, disc-shaped recording media (hereinafter referred to as F discs) used in optical disc devices include master discs used for mass duplication for playback-only video discs and PCM audio discs. There are also disks that have a recording medium adhered to the surface of a substrate made of glass or plastic, which are used in devices with a recording function. The disk to which this invention is applied is a disk used in a device with a recording function.

Figure 2 shows the state of writing information to a conventional disk! ! ! In Figure 9, which is an IT side view, (1) is a disk, (2> is a support, (3) is a light absorption layer, (4) is a laser beam, and (5) is an objective lens. like.

This disk (1) is typically made by forming a vapor-deposited film of a metal such as tellurium on the surface of a support (2) made of glass or plastic, which is typically about 1H thick, and has a light absorption layer (3).
That is.

The original disk recording/reproducing device is a device that records and reproduces information using a laser beam, but in a device equipped with a recorder n1, a laser beam (4) is emitted onto a light absorption layer while rotating the disk (1). The objective lens (5) is used to focus light on the surface of the metal vaporized film (3), and the laser beam is modulated with the information to be injected into the metal vaporized film (3) to make a hole in the metal vaporized film (3) by thermal processing. Information is embedded in form. As such a light absorption layer, a metal vapor-deposited film such as tellurium has favorable characteristics such as less loss of information called signal/noise (S/N) loss, which is called loss-out, and is particularly suitable for semiconductors. When recording with a low power laser such as a laser, a low melting point metal such as tellurium is often used.

[Problem that the invention seeks to solve]

However, in conventional disks in which a low melting point metal such as tellurium is vapor-deposited as a light absorption layer, the metal such as tellurium is easily oxidized, and as the r:R process progresses, the light reflectance decreases. The drawback was that the recording device gradually deteriorated.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain an optical recording medium that can be written with low power and can prevent a decrease in reflectance.

[Means for solving problems]

The optical recording medium of the present invention has a resin material in which at least one of tocopherol and its derivatives and a reduced dithiolate complex are dispersed.

[Effect]

The tocopherol and its derivatives according to the present invention oxidize the reduced dithiolate complex only in the presence of light, forming a dithiolate complex and making recording possible. On the other hand, under dark conditions, oxidation does not occur and no dithiolate complex is formed, so the reflectance does not decrease.

〔Example〕

FIG. 1 is a sectional view showing a state of writing on an optical recording medium according to an embodiment of the present invention.

(11, (23, +4), (5) are the same as in Figure 2, Gυ is the resin material that becomes the light absorption layer, (6) is the reduced product of the dithiolate complex, and (7) is the product of tocopherol and its derivatives. At least one type of

Tocopherol and derivatives thereof according to the present invention include α-tocopherol, β-tocopherol, r-tocopherol, d-tocopherol, 5. T-dimetertocol, T-methylol, 5-methyltocol, tocol, α-tocotrienol, β-tocotrienol, r-)cotrienol, δ-tocotrienol, tocotrienol, α-tocopherol vinegar ester, succinic d-α-tocopherol, Toco7 Elamine.

α-toco7 erothiol, α-toco7 erothioacetic acid, α
- Tocopherodisulfite dimer, α-tocopherocenone 64 and G-α-tocopherology l! L'-/chemicals etc. The chemical structural formula of α-tocopherol is shown below.

The reduced product of the dithiolate complex according to this invention includes:
Bis(1-(4-dimethylaminophenyl)-2-phenylethanedithione)nickel(0) (B D N )
reduction products of bis-(dithiodiacetyl)-platinum, reduction products of bis-(dithiodiacetyl)-nickel, reduction products of bis-(4,4'-dimethoxydithiobenzyl)-platinum, and reduction products of bis-(dithiodiacetyl)-platinum, and bis-(dithiodiacetyl)-platinum reduction products. dithiobenzyl)-platinum reduction products, etc. The chemical structural formula of BDN is shown below.

The resins used in this invention include polymethyl methacrylate (PMM) and polyethyl methacrylate.

Examples include polyethylene and polyvinyl chloride.

The optical recording medium of the embodiment of the present invention is prepared by dispersing at least one of the above-mentioned tocopherols and derivatives thereof and a reduced product of the dithiolate complex in the above-mentioned resin on a support such as glass, quartz plate, or plastic. Obtained by applying and drying a resin material.

Furthermore, when recording using the optical recording medium of the embodiment of the present invention obtained as described above, at least one of the tocopherols and derivatives thereof according to the present invention is
The reduced product of the dithiolate complex is oxidized by external light irradiation according to the formula below, and an absorption band is generated in the band that absorbs the laser beam during readout.

aT top-1ゝαT (11*αT
+02 αTO2t2)1, /2 aTo 2
+ 2 B Dp4 H---aT + B DN +
H2O131 where aT is) coferols, α
Td is an excited state of tocopherols, αTO2 is an oxide of traferols, and BDNH is a reduced product of a dithiolate complex.

BDN is a dithiolate complex.

At this time, equations (1) to (3) progress rapidly and the sensitivity decreases. This is because the reaction proceeds in the 7-oton mode.

Unlike heat mode, recording does not bleed,
It has the advantage of providing high resolution.

In addition, the reactions of formulas (1) to (3) occur only by irradiation with ultraviolet light, and the reduced product of the dithiolate complex exists stably under dark conditions. Therefore, the dithiolate complex is not generated in the unexposed area. Furthermore, it is not sensitive to the laser oscillation wavelength for laser light during readout. Therefore, since there is no decrease in the reflection intensity, a product with a high contrast ratio can be obtained even after long-term storage.

Here, the contrast ratio is defined as the absorbance of the part irradiated with ultraviolet light. The absorbance of the non-irradiated portion is defined as R2 by the following formula. That is, the contrast ratio is the ratio of the difference between the recorded portion and the unrecorded portion to the recorded portion, and represents the sharpness of the recording.

Note that if the support is made of a highly reflective material, it is possible to read out the recorded information even with one reflected light.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

Example 1 a-) Core xct-rule 1ji part, BDN
(1) (04H9) Reduction by N $11 Heavy part 2 and PM
Dissolve 8 parts by weight of person M in 92 parts by weight of acetone. This material was coated on a glass disk with a diameter of 3° using a Whaler to a final thickness of 10 μm, and dried at room temperature to obtain an optical recording medium according to an embodiment of the present invention. As shown in Figure 1, apply 10μ of ultraviolet light (light intensity of 2m/<i) to this material.
A small number of spots were irradiated and recorded on the optical recording medium for 200 μS. At this time, the reduced form of BDN is 11060n
It becomes an oxide with an absorption peak at . As a result, the contrast ratio was 0.5.

When the optical recording medium was left in a dark place for several months and then recorded under the following conditions, the contrast ratio was 0.4 and no significant decrease in sensitivity was observed.

Next, the information recorded on the optical recording medium of the embodiment of the present invention was read out as shown in FIG.

FIG. 3 is a cross-sectional view showing the state of reading information recorded on an optical recording medium. In FIG. 1, (8) is a Nd-YAG
The laser and (9) are photodetectors. That is, in the optical recording medium of one embodiment of the present invention in which the above information is embedded,
Light of 11060 nm is irradiated, and changes in the transmitted light are detected by a photodetector (9).

Comparative Example When a glass disk with a thickness of 10 μm and a diameter of 30 cm was deposited with Dellu and irradiated with a laser diode with a light intensity of 2 mW/cdt for 200 μS, the contrast ratio was 0.
4 records were obtained. When this disc was left in a dark place for one month and recorded under the same conditions, the contrast ratio was 0.2] and a significant decrease in sensitivity was observed.

[Effects of the Invention] As explained above, this invention enables writing with low power by using a resin material that disperses at least one of tocopherol and its derivatives and a reduced product of a dithiolate complex. At the same time, it is possible to obtain an optical recording medium that can prevent a decrease in reflectance.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing how information is written to an optical recording medium according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing how information is written to a conventional disk, and FIG. FIG. 2 is a cross-sectional view showing a state of reading information recorded on an optical recording medium according to an embodiment of the invention. In the figure, (3j is a resin material, (6) is a dithiola) M
The reduced product (7) is at least one of tocopherol and its derivatives. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) An optical recording medium comprising a resin material in which at least one of tocopherol and its derivatives and a reduced dithiolate complex are dispersed. (2) The optical recording medium according to claim 1, wherein the dithiolate complex reduction product is a reduction product of bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0). .