JPS60163245A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To improve light stability and increase the number of times durable for reading-out particularly by incorporating a specific stabilizer into any one or more layer of an optical information recording layer provided with a thin film recording layer consisting essentially of a cyanine dye or merocyanine dye on a substrate and provided, if necessary, with an undercoating layer and protective layer thereon. CONSTITUTION:The compd. expressed by the formula I [R is H or lower alkyl, X is an acid anion, m is 0, 1 or 2, A is the connecting group expressed by the formula II (n is 1 or 2) or the connecting group expressed by the formula III (in this case m is 2), all the arom. nuclei of the compd. expressed by the formula I may be substd. by lower alkoxy, halogen or OH] is incorporated into at least one layer of an optical information recording medium having a thin film recording layer 2 consisting essentially of a cyanine dye or merocyanine dye on a substrate 1 and having, if necessary, an undercoating layer 3 or protective layer 4. The recording medium is thus provided with excellent optical stability and a large number of times durable for reading-out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention particularly relates to an optical information recording medium with improved photostability and durability against continuous printing.

[Prior art]

2. Description of the Related Art Conventionally, an information recording and reproducing apparatus is known that records and reproduces information by irradiating a rotating disc-shaped information recording medium with an IC laser beam. As an information recording medium used in this type of information recording device, one is known that is composed of a substrate, a metal reflective film, and a translucent colored layer containing a dye.

In this recording medium, laser light incident on a semi-transparent colored layer containing a dye reaches a metal reflective film and is reflected so that the reflected light can be easily detected. It is provided to compensate for the amount of reflected light that is insufficient with the colored layer alone. However, the presence of the metal reflective film complicates the structure of the information recording medium and causes an increase in cost. Therefore, it has been proposed to eliminate the above-mentioned drawbacks by using an organic dye monolayer film with high reflectance and bronze luster. In particular, when a cyanine dye with high light absorption is used as a recording film, a light-absorbing and reflective film that exhibits metallic luster (reflectance of 20-30 inches) can be obtained with a film thickness of 600X to 600mm, and is capable of laser recording and reflective readout. It becomes possible. In particular, the use of a semiconductor laser with a wavelength of 750 to 850 nm as a laser light source has the advantage that the device can be made smaller. However, organic dyes generally suffer from oxidation, resulting in a decrease in storage stability.

〔the purpose〕

The present invention has been made in view of the above problems, and its purpose is to improve the storage stability of organic dye-based recording layers, particularly cyanine or merocyanine dye-based recording layers, which are expected to have high resolution, high recording density, and high sensitivity. The objective is to improve the stability against irradiation. Further, an object of the present invention is to provide an optical information recording medium having a high recording density/total ratio and excellent storage stability.

〔composition〕

In order to achieve the above object, the present invention provides the following general formula (1
) is contained in at least one of the organic dye thin film recording layer and an optional undercoat layer and protective layer.

The compound used in the present invention has the general formula [wherein R
represents hydrogen or a lower alkyl group, X represents an acid anion, m is 0.1 or 2, A is e (n is 1
or 2) or 0 (where m is 2) and all aromatic nuclei present are lower alkyl groups,
may be substituted with a lower alkoxy group, halogen or hydroxyl group].

Examples of acid anions in the general formula (1) include hexafluoroarsenate ion, hexafluoroantimonate ion, fluoroborate ion, perchlorate ion, trifluoroacetate ion, periodate ion, etc. I can give it to you. Further, as representative examples of the compound of general formula (1), the following compounds A-L are exemplified.

<　III　C,l　Q　cI:ll! c.

6 Country 1-1 +-3'pd A The organic dye thin film recording layer used in the present invention has a cyanine dye or merocyanine dye as a main component, and may also contain other dyes, compounds, binders, etc. . Any cyanine dye and merocyanine dye can be used, but typical examples thereof include the following general formulas (
There are compounds represented by 2) and (6).

However, R1 and R2 may be the same or different, and each is an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an aralkyl group, a carboxyalkyl group, a carboxyalkylate group bonded to an alkali metal cation, a sulfoalkyl group, Represents a sulfoalkyl group or a sulfonate alkyl group bonded to an alkali metal cation, and zl and Z2 are atoms capable of forming a fused ring containing a 5-negative or 6-membered double ring or a 5- or 6-membered heterocycle t represents an integer of 1 to 4 and/or represents an acid anion.

Regarding the undercoat layer and protective layer provided as necessary on the organic dye thin film recording layer in the present invention, the undercoat layer (a) improves adhesion, (b) serves as a barrier against water and gas, and ( C) Improving the storage stability of the recording layer and (d)
Used for purposes such as improving reflectance. For the purpose of (a), polymeric materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones,
Various substances can be used, such as liquid rubber; (b)
For this purpose, inorganic compounds such as 5i02. , MgF2.5iO1Ti02, ZnO2
Such.

Metal or semimetal materials such as Zn, Cu, S, Ni, C
r.

Ge, Se, Cd, Ag, At, etc. can be used, and for the purpose of (C), the above (a) and (
Materials such as those exemplified for b) and metals such as Ag, Al, etc. can be used for the purpose of (d). In addition, the protective layer protects from scratches, dust, dirt, etc.
It is provided for the purpose of improving the chemical stability of the recording layer, and the same material as the undercoat layer can be used as the material.

Next, a configuration example of the optical information recording medium of the present invention will be explained with reference to the drawings.

As shown in FIG. 1, the optical information recording medium of the present invention basically comprises a substrate 1 and an organic dye thin film recording layer 2 containing the compound of general formula (1) above. Further, the recording layer may be laminated with other layers such as a reflective layer. The recording layer can be formed by known means such as vapor deposition and coating. When a coating method is used, it is dissolved in an organic solvent such as dichloroethane and sprayed or roller coated.

This is done by conventional coating methods such as dipping and spinning. Recording layer film J'JId, 1
It is appropriate that ooX ~1 μm and t L<u200 to 3000 μm.

Furthermore, as shown in FIGS. 2 to 4, an undercoat layer 3 and/or a protective layer 4 are further provided, and the compound of the general formula (1) is added to at least one of the layers, thereby achieving the present invention. It is possible to achieve the goal. In this case, the recording layer may or may not contain the above compound. The amount of the compound of general formula (1) added is preferably 2 to 60% by weight for the recording layer based on the total solid content, preferably 5 to 40% by weight, and for the undercoat layer or protective layer. A suitable amount is 2 to 90% by weight, preferably 10 to 50% by weight. Also,
The thickness of the undercoat layer is 0.1 to 60 μm'l! Preferably 0
．． The range is 2 to 10 μtn, and the thickness of the protective layer is 0.1
A suitable thickness is at least μm, preferably at least 50 μm.

Furthermore, as another configuration of the optical information recording medium according to the present invention, two recording media of the same -r4 configuration shown in FIGS. It may be a so-called air sandwich structure in which a thin film recording layer is placed inside and sealed, or a so-called close-contact sandwich structure (laminated 9-ply structure) in which a thin film recording layer is placed inside and sealed.
You can also do this.

The substrate in the present invention must be transparent to the laser 1 used when writing and recording is performed from the substrate side, and does not need to be transparent when writing and recording is performed from the recording side. Glass, polycarbonate, and polymethyl methacrylate are commonly used as the substrate, but any other material used for recording media may be used.

〔Example〕

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

Example 1 The dye of the general formula and the above-mentioned Exemplary Compound A were dissolved in 1,2-dichloroethane at a weight ratio of 100:15, and this was spin-coated onto a polymethyl methacrylate (hereinafter abbreviated as rPMMAJ) substrate to a thickness of approximately A recording layer of 500^ was formed. A semiconductor laser beam with a wavelength of 790 nm was applied to the recording medium thus prepared from the substrate side at a recording frequency of 0.6875 MH.
Recording and playback were performed with a bit length of 0.9 μm and a vector analysis (scanning filter, bandwidth 50 KH).
z) to measure the initial reflectance and C/N. Next, the reflectance and C/N were measured after irradiating the same recording medium with 54,000 lux tungsten light for 50 hours.

Example 2 In place of the dye and compound A described in Example 1, a dye of the general formula % and the above-mentioned exemplified compound G were used, and the mixing ratio was 1.
A recording medium was produced and evaluated in the same manner as in Example 1 except that the time was 00:30.

Example 3 A recording medium was prepared and evaluated in the same manner as in Example 1 except that Compound C was used instead of Compound A described in Example 1.

Example 4 A recording medium was prepared and evaluated in the same manner as in Example 1, except that the dye and compound A of the general formula were used in place of the dye and compound A described in Example 1.

Example 5 Compound 1 and polycarbonate in a weight ratio of 7:6,
A 0.2-μm-thick undercoat layer was formed by coating a solution dissolved in 2-dichloroethane on a PMMA substrate, and a recording layer containing only the cyanine dye described in Example 4 was provided on top of the undercoat layer to produce a recording medium. We conducted an evaluation.

Example 6 On the recording layer formed in Example 1, compound A and polyamide resin dissolved in methanol at a weight ratio of 7:6 was coated to provide a 1 μm thick retaining tφ layer to produce a recording medium. We conducted an evaluation.

Comparative Example 1 A recording medium was prepared and evaluated in the same manner as in Example 1, except that a recording layer consisting only of the dye used in Example 1 was formed.

Comparative Example 2 A recording medium was prepared and evaluated in the same manner as in Example 2, except that a recording layer consisting only of the dye used in Example 2 was formed.

Comparative Example 6 A recording medium was prepared and evaluated in the same manner as in Example 4, except that a recording layer consisting only of the dye used in Example 4 was formed.

The evaluation results of the optical information recording media produced in Examples 1 to 6 and Comparative Examples 1 to 3 are summarized in the table below.

〔effect〕

The optical information recording medium of the present invention constructed as described above provides excellent optical stability and read resistance.

[Brief explanation of the drawing]

1 to 4 are cross-sectional views showing the structure of the optical information recording medium of the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Organic dye thin film recording layer, 6...
Undercoat layer, 4...A preservation layer. Patent applicant Rico Co., Ltd. -1, -J-1 Figure 1 Figure 2 Figure 3 Figure 4 Garden

Claims (1)

[Scope of Claims] A thin organic dye recording layer containing a cyanine dye or merocyanine dye as a main component on a substrate, and at least one of the recording layer and an optional undercoat layer and a protective layer. In two layers, the general formula (1) [wherein R represents hydrogen or a lower alkyl group, X represents an acid anion, and m spans 0.1] or =C=
(provided that m is 2) and all aromatic nuclei present are lower alkyl groups, lower alkoxy groups,
characterized by containing a compound represented by [optionally substituted with rogene or hydroxyl group]
Optical information recording medium.