JPS63288786A - Optical recording medium - Google Patents

Abstract

PURPOSE:To contrive enhancement of stability of a product through prevention of deterioration of light resistance or deterioration on reproduction or through improvement of solubility, by providing a recording layer comprising a light- absorptive reflective coloring matter and a specified transition metal complex, on a substrate. CONSTITUTION:A recording layer comprising a light-absorptive reflective coloring matter and a transition metal complex of the formula is provided on a substrate. In the formula, R1 is H, an alkyl, halogen or substd. amino, n is an integer of 0-4, R2 is a substd. or unsubstd. alkyl, alkoxyl, aralkyl or aryl, M is Ni, Pd or Pt, and X is a cation. The cation is generally preferably quaternary ammonium or quaternary phosphonium. The complex is preferably incorporated in the recording layer in an amount of 10-40 wt.% based on a polymethine coloring matter contained in the recording layer. The film thickness of the recording layer is preferably 100 Angstrom -10 mum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical recording medium used in an optical disk memory device, and particularly to an optical recording medium used in a method of directly recording with a laser beam and reproducing information by changing reflected light.

[Prior art]

Recently, organic dye films made of light-absorbing and reflective dyes such as cyanine dyes, triarylmethane dyes, merocyanine dyes, naphthoquinone dyes, xanthine dyes, and squalium dyes have been used instead of metal recording layers as recording layers in optical recording media. Proposed. The advantage of organic dye films is that they have low melting points, low decomposition temperatures, and low thermal conductivity, allowing for high sensitivity and high density.

Because the film can be formed using a coating method, mass production is high and costs can be expected to be reduced.

However, when the above-mentioned dyes are used, there is a problem that the storage stability of the recording medium against light, the storage life after recording, and the storage stability against repeated irradiation with readout light after recording, that is, against reproduction light, are insufficient. In addition, the solvent used for forming the dye film is limited to halogenated hydrocarbons and the like, which tends to crystallize during the film formation process, which poses a practical problem.

〔the purpose〕

The purpose of the present invention is to improve the stability of optical recording media using light-absorbing and reflective dyes by (1) preventing light resistance and playback deterioration, and (2) preventing crystallization based on improved solubility. At the point.

〔composition〕

The present invention is an optical recording medium characterized by having, on a substrate, a recording layer containing a light-absorbing and reflective dye and a transition metal complex represented by the following general formula.

In the general formula, R4 is selected from the group consisting of hydrogen, alkyl gc halogen, and substituted amino group, n is an integer of 0 to 4, R2
is selected from the group consisting of substituted or unsubstituted alkyl, alkoxy, aralkyl and aryl groups, and M is N
selected from the group consisting of x * P d + P t, where X is a cation.

As specific examples of the compound represented by the formula (1), the following can be exemplified.

(Left below) Specific examples of metal complex components The cation is generally preferably quaternary ammonium or quaternary phosphonium.

Specific examples of cation components
a3) tv) P@(n-C,H,).

V) P” (CzHs) (CzHs3) a
vi) P@(C,H,,) 4 The basic layer structure of the optical recording medium according to the present invention is that a recording layer containing a polymethine dye and a metal complex of the above general formula (1) is directly provided on a substrate. However, if necessary, an undercoat layer can be provided between the substrate and the recording layer, or a protective layer can be provided on the recording layer. Alternatively, the pair of recording media configured in this manner may be formed into an air sandwich structure in which the recording layer is placed inside and sealed with another substrate through a space, or a tight sandwich structure in which the pair of recording media is bonded through a protective layer. A laminated structure) may also be used.

Examples of light-absorbing and reflective dyes, particularly polymethine dyes, used as the main component of the recording layer in the present invention include cyanine dyes, merocyanine dyes, croconium dyes, and pyrylium dyes. Among them, cyanine dyes and merocyanine dyes are preferably represented by the following general formula.

Cyanine dyes, provided that R and R may be the same or different and each represents an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an aralkyl group, a carboxyalkyl group, a carboxyalkylate group bonded to an alkali metal cation, or a sulfonate group. represents an alkyl group, a sulfoalkyl group, or a sulfonate alkyl group bonded to an alkali metal cation; Z8 and Z2 represent a 5- or 6-membered heterocycle or a fused ring containing a 5- or 6-membered heterocycle; Q represents an integer from 1 to 4, and X represents an acid anion.

(Margin below) merocyanine pigment represents a ring such as C,H.

and n represents 1 or 2.

Representative examples of the above dyes are shown below, but the present invention is not limited thereto.

The recording layer in the present invention is composed of a polymethine dye and a metal complex of the above general formula, but in order to improve recording characteristics and stability, other dyes such as evaphthalocyanine, tetrahydrocholine, dioxazine, triphetchazine, etc. type, phenanthrene type, anthraquinone (indanthrene) type, xanthine type, triphenylmethane type, triphenylamine type, azulene type, or metals and metal compounds such as In, Sn.

T e g B x g A Q p S e p A
g HT e○,, SnO.

It may be mixed and dispersed with Cu or the like, or it may be laminated.

Further, other third components such as binders, stabilizers, various plasticizers, surfactants, antistatic agents, dispersants, etc. may be included as necessary.

The weight ratio of the polymethine dye contained in the recording layer of the present invention to the metal complex represented by the above general formula (R) is preferably 10 to 40% of the metal complex to the polymethine dye.

The thickness of the recording layer is 100 to 10 μm, preferably 200 to 2 μm. Film forming methods include solution coating methods such as dip coating, spray coating,
Spinner coating, blade coating, roller coating, curtain coating, etc., or other methods such as vapor deposition, CVD, and sputtering can also be used. Examples of solvents used for coating include alcohols such as isopropyl alcohol, ketones such as methyl ethyl ketone, esters such as m-ethyl acid, ethers such as methyl cellosolve, alkyl halides such as dichloroethane and chloroform, toluene, xylene, etc. Examples include aromatic systems and mixtures thereof. Further, the material of the substrate on which the recording layer is provided is not limited in any way, and materials known in this field such as various plastics, glasses, ceramics, metals, etc. can be used.

〔effect〕

According to the optical recording medium of the present invention, it is possible to increase the number of readouts after recording, that is, to prevent deterioration due to reproduction light, to improve storage stability against light, and to simplify the manufacturing process and reduce costs.

〔Example〕

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.

Example 1 Cyanine dye of the compound example (A) (Nippon Kanko Shiki Co., Ltd.
K-2421) 0°7% methanol/2.2'-
A dichloroethane (8/2 vol) solution was prepared, and (l,2-dithioferlate)-(1,2-parafluorobenzene 1,2) of Compound Example 8 was added to it at a weight ratio of 15%.
- ethylene thiolate) nickel tetra-n-butylammonium salt was dissolved. This solution was applied onto a glass substrate and dried to form a recording layer with a thickness of 600 mm, thereby producing a recording medium.

This recording medium was irradiated with light of 54,000 lux using a 500 watt tungsten lamp, and then the rate of decrease in the absorption peak of the dye was measured. These results were compared to those using the same dyes but with no nickel complex added and (if) bis-(1,2,4)-trichloro-5,6-
When compared with the addition of cythiophyl-tonite (U) tetra-n-butylammonium, the rate of decrease was relative to 0.17 for (i) and 0.71 for (n). Ta. Furthermore, when we checked the stability of the same recording medium against reproduction light, we found that (i)
8.2 times more than that of the above and 1 times more than that of (n) above
．． Improved by more than 4 times.

Example 2 (4-t-
The recording medium was prepared in the same manner as in Example 1 except that tetra-n-butylammonium of butyl-1,2-dithioferlate)-(1,2-parachlorobenzene-1,2 ethylene thiolate)nickel was used. was prepared and measured, and the relative value of the decreasing rate of the absorption peak was 0.13 for (i) above and 0.56 for (n). The stability against reproduction light is also 1.4 times that of (i), (
n) was improved by more than 1.8 times.

Claims (1)

[Scope of Claims] 1. An optical recording medium having, on a substrate, a recording layer containing a light-absorbing and reflective dye and a transition metal complex represented by the following general formula. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ In the formula, R_1 is selected from the group consisting of hydrogen, alkyl, halogen, and substituted amino group, n is an integer from 0 to 4, and R_2 is substituted or unsubstituted alkyl. , alkoxy, aralkyl, and aryl groups, M is selected from the group consisting of Ni, Pd, and Pt, and X is a cation.