JPH01234293A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To contrive higher light resistance and prevention of deterioration upon reproduction, by incorporating a specified oxovanadium complex into a recording layer containing an organic coloring matter comprising a polymethine compound as a main constituent. CONSTITUTION:An oxovanadium complex of the formula is incorporated in a recording layer containing an organic coloring matter comprising a polymethine compound as a main constituent. The amount of the oxovanadium complex in the recording layer is desirably 10-40wt.% based on the polymethine coloring matter. The film thickness of the recording layer is preferably 100Angstrom -10mum. By this, it is possible to contrive an increase in the number of times of reading permitted after recording, namely, prevention of deterioration by reproducing light, and to contrive higher preservability against light. In the formula, R is an alkyl or alkylene ring, and Z is a hetero-atom of N or O.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an improved optical information recording medium that can be used in the optical recording field, and more particularly to an optical disk on which information is recorded and reproduced using a laser beam. The present invention relates to optical information recording media used in memory devices and the like.

[Prior art]

For some time, optical information recording media have been proposed in which a recording layer made of a low melting point metal or a low melting point metal and a dielectric material is provided on a substrate, but these have poor storage stability, low resolution, and recording density. It has disadvantages such as low yield, difficult manufacturing conditions, and high cost. Therefore, 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 thin films as recording layers. Proposed.

This organic dye film has a low melting point 1 decomposition temperature and low thermal conductivity, so it has the potential for high sensitivity and high density, and because film formation can be done by coating, it has high productivity and low cost. There are many benefits that can be expected.

However, in a recording layer composed of the above-mentioned dye,
There was a problem in that the organic dye film sometimes faded (regenerated deterioration) due to irradiation with natural light or a reproducing laser beam, resulting in a lack of long-term stability.

In addition, the solvent used in forming the organic dye film is limited to halogenated hydrocarbons, etc., and it tends to crystallize in the paint for forming the dye film or the formed film, which poses a problem in practical use.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a stable optical information recording medium that has improved light resistance, can prevent reproduction deterioration, and eliminates problems of solubility and crystallization during formation of a recording layer.

〔composition〕

The above object is achieved by incorporating an oxovanadium complex represented by the following general formula into a recording layer containing an organic dye containing a polymethine compound as a main component in an optical information recording medium.

(In the above formula, R represents an alkyl or alkylene ring, and Z represents a heteroatom of N or 0.) The optical information recording medium of the present invention basically comprises an organic dye containing a polymethine compound as a main component on a substrate. , is constructed by providing a recording layer made of an oxovanadium complex represented by the above general formula, but if necessary, an undercoat layer may be provided between the substrate and the recording layer, or a protective layer may be provided on the recording layer. Be able to do it.

Alternatively, the pair of recording media constructed 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 an air-sandwich structure in which the pair of recording media is bonded through a protective layer is used. (combined structure).

Next, the materials constituting the optical information recording medium of the present invention and the necessary characteristics of each layer will be specifically explained.

(1) Substrate The required characteristics of the substrate are that it must be transparent to the laser beam used only when recording and reproducing are performed from the saw plate side, and it does not need to be transparent when recording and reproducing is performed from the recording side. As the substrate material, for example, plastics such as polyester, acrylic resin, polyamide, polyolefin resin, phenol resin, epoxy resin, polyimide, glass, ceramic, or metal can be used.

Note that a preformat such as an address signal or a pregroove for a guide groove may be formed on the surface of the substrate.

(2) The S-layer recording Jn is a type that causes some kind of optical change by irradiation with laser light and can record information based on that change. Contains oxovanadium complex.

Specific examples of oxovanadium complexes preferably used in the present invention are shown below, but the present invention is not limited thereto.

Bis(N,N-dimethyldithiocarbamate)oxovanadium(IV)bis(N,N-diethyldithiocarbamate)oxovanadium(IV)H Small 5”S”S”C
Complexes of 711゜bis(N,N-diisopropyldithiocarbamate)oxovanadium(IV)bis(pyrrolidine-N-carbodithioate)oxovanadium(IV) are, for example, Bj, McCORMICK; Inorgani
As an example, an example of the synthesis of bis(pyrrolidine-N-carbothioate)oxovanadium(IV) can be described. After dissolving 3.98 parts by weight of aqueous salt in 25-g warm water, ethanol 2
A solution containing 5d was gradually added to a solution of 6.56 parts by weight of ammonium pyrrolidine-N-carbodithioate in 50% ethanol, and by stirring, a dark green crystalline powder was precipitated. The mixture is filtered, washed with water and ethanol, and dried to obtain 6.42 parts by weight of a complex. Absorption spectrum is λmax 788 nm (dimethyl sulfoxide solution)
shows.

Furthermore, the polymethine dye includes at least one of cyanine dyes, merocyanine dyes, croconium dyes, pyrylium dyes, and the like.

As cyanine dyes and merocyanine dyes, those represented by the following general formulas (1), (II) and (R1) can be used.

Cyanine dye or provided that R1 and R2 represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or an alkenyl group, and zl and z2 are atomic groups necessary to complete the substituted or unsubstituted heterocycle. , Z3 represents an atomic group necessary to complete a substituted or unsubstituted 5-membered ring or 6-membered ring, and the 5-membered ring or 6-membered ring may be fused with an aromatic ring, and R3 represents a hydrogen atom or a halogen atom, R4 and R6 represent a hydrogen atom, a halogen atom, a hydroxy group, a carboxyl group, an alkyl group, a substituted or unsubstituted aryl group or an acyloxy group, xe represents an acid anion, and L m and n
is O or 1.

merocyanine pigment 4hs n represents 1 or 2.

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

II, l L111 As mentioned above, the recording layer of the present invention is mainly composed of a polymethine dye alone or a combination of these dyes, and an oxovanadium complex, but in order to improve recording characteristics and stability, , other dyes 1 such as phthalocyanine, tetrahydrocholine, dioxazine, triphetchazine, phenanthrene, anthraquinone (indanthrene), xanthine, triphenylmethane, triphenylamine, azulene dyes, Metals or metal compounds, such as In, Sn, Te, Bi, AQ
, Se, , Ag.

It may be mixed and dispersed with TeO□, SnO, Cu, etc., or may be laminated, and if necessary, other third components such as binders, stabilizers, various plasticizers, surfactants, antistatic agents, and dispersions may be added. It may also contain agents.

The weight ratio of the polymethine dye to the oxovanadium complex contained in the recording layer is preferably 10 to 40% of the oxovanadium complex to the polymethine dye, and the thickness of the recording layer is 100 to 10%, preferably 200% Man~
There are two units. As a film forming method, a solution coating method 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 ethyl acetate, ethers such as methyl cellosolve, alkyl halides such as dichloroethane and chloroform, toluene, xylene, etc. Examples include aromatic systems and mixtures thereof.

(3) Undercoat layer The undercoat layer (a) improves adhesion, (b) serves as a barrier against water or gas, (c) improves storage stability of the recording layer, and (d)
) improvement of reflectance, (e) protection of the substrate from solvents, (f)
Used for purposes such as forming pre-grooves. (a
), various polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents can be used. ,(b)
For the purpose of (c), inorganic compounds such as Bib, MgF2.5iO1Tie,
, ZnO, TiN, SiN, etc. Metals or metalloids such as Zn, Cu, S, Ni, Cr, Ge,
Se, Au, Ag, AQ, etc. can be used. Also, for the purpose of (d), metals such as Af
l, Ag, etc., and organic thin films with metallic luster, such as methine dyes.

Xanthine dyes etc. can be used, and (e) and (
For the purpose of f), ultraviolet curing resins, thermosetting resins,
Thermoplastic resin or the like can be used.

(4) Protective layer The protective layer is used to (a) protect the recording layer from tin, dust, dirt, etc., (b) improve storage stability of the recording layer, (c) improve reflectance, etc. be done. For these purposes, the materials listed above for the undercoat layer can be used.

In the present invention, the undercoat layer and the protective layer may contain stabilizers, dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, etc., as in the case of the recording layer. . Furthermore, the undercoat layer and the protective layer can also contain a polymethine compound.

〔effect〕

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

〔Example〕

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

Example 1 A 0.7% methanol/2.2'-dichloroethane (8:2 volume ratio) solution of the cyanine dye of Compound Example (A) was prepared, and the compound bis(pyrrolidine- N-carbodithioate) oxovanadium (T
V) was dissolved. This solution was applied onto a glass substrate and dried to form a 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 without the addition of (a) oxovanadium complex and (b) bis-(1,2,4)-trichlor-5.
,6-thiophyl-tonitskel(11)tetra-n-
Compared to the one with butylammonium added, the relative reduction rate was 0.13 for (a) and 0.65 for (b). Furthermore, we confirmed the stability of the same recording medium against playback light.
This was improved by 15 times or more than the above (a) and 1.5 times or more than the above (b).

Example 2 A recording medium was prepared and measured in the same manner as in Example 1, except that bis(N,N-diethyldithiocarbamate)oxovanadium (IV) was used as the metal complex. The absorption peak decreasing rate is a relative value of 0.10 relative to (a) above.
and for (b) it was 0.55. The stability against reproduction light was also improved by more than 12 times compared to (a) and by more than 1.7 times compared to (b).

Claims (1)

[Claims] (1) In an optical information recording medium, in which a recording layer containing an organic dye containing a polymethine compound as a main component is provided on a substrate directly or via an undercoat layer, and a protective layer is further provided as necessary, in the recording layer. An optical information recording medium characterized by containing an oxovanadium complex represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the above formula, R represents an alkyl or alkylene ring, and Z represents a heteroatom of N or 0)