JPS63189291A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To improve the light resistance of an optical information recording medium, prevent deterioration of its data retrieving efficiency and reduce cost by adding a specific compound to a polymethine coloring matter sewing as a main component of a recording layer. CONSTITUTION:A recording layer consisting mainly of polymethine coloring matter is provided on a base directly or through a primary layer. In addition, a protective layer is provided on the recording layer, if necessary. In a recording medium of the above constitution, a compound expressed in the formula (1) is added. In the formula, R1, R2, R3 and R4 represent hydrogen or -SO2N(R5)2, R5 the alkyl group of upto 8 carbon atoms or hydrogen, and at least one of R1, R2, R3 and R4 -So2N(R5)2.M represents Cu, V, VO2, Pb, Ni, SnCl2, Mn, Zn or Sn. If the compound of the formula is added to the recording layer, it shows a superior preventive effect for improvement of the light resistance and for prevention from data retrieving efficiency of the optical information recording medium. However, the compound can be added to layers other than the recording layer, for instance, the primary layer or protective layer to increase said effect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical information recording medium subjected to writing and recording using a laser, particularly a semiconductor laser, and more particularly to an improvement in an organic thin film recording layer containing polymethine color X as a main component.

[Prior art]

2. Description of the Related Art Conventionally, information recording and reproducing apparatuses are known that record and reproduce information by irradiating a rotating disk-shaped information recording medium with a laser beam. As an information recording medium used in this type of information recording device, one in which a recording layer made of a low melting point metal or a low melting point metal and a dielectric is provided on a substrate has been proposed. However, these have drawbacks such as poor storage stability, low resolution, low recording density, and difficult manufacturing conditions and high costs.

Therefore, it has recently been proposed to use an organic dye thin film as the recording layer in place of the metal thin film. This organic dye thin film has a low melting point, low decomposition temperature, and low thermal conductivity, so it has the potential for high sensitivity and high density.Furthermore, because film formation can be done by coating, mass production is high and costs can be reduced. It has advantages in that it can be expected.

However, at present, recording media using such organic dye #films still lack sufficient stability against light and heat, and storage stability against reproduction light after recording.

〔the purpose〕

The present invention has been made in view of the above problems, and its purpose is to improve the light resistance of optical information recording media, prevent playback deterioration, and reduce costs.

〔composition〕

The present invention is based on the discovery of a specific compound which improves the lightfastness of polymethine dyes and which can be solubilized in alcoholic solvents and applied directly to injection molded substrates. That is, the above object of the present invention is achieved by incorporating a compound of the following general formula into the polymethine dye, which is the main component of the recording layer. However, R1, R2, R5 and R4 are each hydrogen or -8O2N(R5)2 and R5 represents an alkyl group having up to 8 carbon atoms or hydrogen, and at least one of R1, R2, Rj and R4 represents -802N(R5)2k. M is Cu5V% VO
z, Pb5Ni, 5nC12, blood, Zn or Sn
f represents. Furthermore, on the aromatic ring in the above formula, -8O2
Substituents other than N(R5)2 may be present, such as halogen, alkyl or alkoxy.

The optical information recording medium of the present invention is basically formed by providing a recording layer t-containing the compound of the above general formula and a polymethine dye on a substrate. However, 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. 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.

When added to the recording layer of the present invention, the compound of the above general formula shows excellent effects in improving the light resistance of the optical information recording medium and preventing playback deterioration. It can be added to the layer or both layers to enhance its effect. The weight ratio of the polymethine dye and the compound of the above general formula in the recording layer of the present invention is 30
i70 to 99:1 light or 60:40 to 95
:5.

Furthermore, 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 As a necessary characteristic of the substrate, it must be transparent to the laser beam used only when recording and reproducing is performed from the substrate side, and does not need to be transparent when recording and reproducing is performed from the recording side. Examples of substrate materials include plastics such as polyester, acrylic resin, polyamide, polycarbonate, polyolefin resin, phenol resin, epoxy resin, and polyimide;
Glass, ceramic, metal, etc. 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.

Further, from the viewpoint of cost, it is most preferable to use a substrate manufactured by injection molding.

2) Recording layer The recording layer is capable of producing some optical change by irradiation with laser light and recording information based on the change, and its main component is a polymethine dye. Contains compounds.

Typical examples of polymethine dyes include cyanine dyes, merocyanine dyes, roconium dyes, and hyrylium dyes.

Further, representative examples of the compounds of the above general formula according to the present invention are all shown in the table below, but the invention is not limited thereto.

The compound of the above general formula according to the present invention may be combined with two or more dyes in order to improve recording properties and stability. Thread), xanthine thread, pigments or metals such as triphenylmethane, triphenylamine, azulene, etc.
Bi, A7. It may be mixed or laminated with Se5Ag5Cu or metal compounds such as 'reo2, SnO, etc. In addition, the recording layer contains polymer materials, storage stabilizers (for example, gold, l!14a, phenolic compounds, etc.), dispersants, flame retardants, lubricants, antistatic agents, plasticizers, etc. Good too.

The recording layer can be formed by conventional means such as vapor deposition, sputtering, CVD or solution coating.

In the case of solution coating, organic solvents such as alcohols,
Ketones, amides, ethers, sulfoxides, esters, aliphatic halogenated hydrocarbons, aromatic polymethine dyes In some cases, the above compounds are dissolved in sprays, spinners, derags, blades, rollers, etc. This is done by conventional coating methods. &! The thickness of the recording layer is 100X to 10μm, preferably 200X to 2μm.
It is.

3) Undercoat layer The undercoat layer is (a)! ! f! (b) barrier against water or gas, (c) improvement in storage stability of the recording layer and (d) improvement in reflectance, (e) protection of the substrate from solvents, (f) pre-treatment. Used for purposes such as forming grooves. For the purpose of (a), various polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones, liquid rubbers, and silane coupling agents can be used. ,(
For the purposes of b) and (c), inorganic compounds such as 5to2, MgF2.5iO1Ti may be used in addition to the above polymer materials.
02, ZnO, TiN.

Metals or metalloids such as SiN, e.g. Zn, Cu
%S, Ni, Cr5()e, Be, %Au, Ag5Al
For the purpose of (d), dyes having metals such as Ag5Als, metallic luster gold, and the like, such as methine-based color patches and xanthine-based dyes, can be used. For the purposes (e) and (f) above, ultraviolet curable resins, thermosetting street resins, thermoplastic resins, etc. can be used. The thickness of the undercoat layer is 11 to 30 μmQ or 0
．． A suitable thickness is 2 to 10 μm.

4) Protective layer The protective layer is provided for the purpose of protecting the recording layer from kisses, dust, dirt, etc., and improving the storage stability and reflectance of the recording layer, and is made of the same material as the undercoat layer. can do. The thickness of the protective layer is suitably α05 μm or more and preferably 5 μm or less.

Note that the undercoat layer and the protective layer may contain stabilizers, dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, and the like.

〔effect〕

According to the optical information recording medium of the present invention configured as described above, it is possible to obtain a recording medium that has high stability against heat and light, excellent storage stability, and little reproduction deterioration. Furthermore, even if a long wavelength laser (semiconductor laser) is used, recording can be performed with high sensitivity, pits can be formed in a good shape, and high C/N can be obtained. A recording layer can be formed by direct coating on an injection molded substrate, resulting in a significant cost reduction.

〔Example〕

Examples below along with comparative examples? The present invention will be further explained below, but the present invention is not limited to these Examples.

Example 1 A pitch of 1.62 m and a groove width of 0.5 mm were formed on an injection molded polycarbonate substrate with a thickness of 1.21 m and a diameter of 2001111 mm.
A spiral guide groove with a depth of 3 μm and a depth of 950× was formed using 7 otobolimer, and on top of this, the dye of the following formula (1) and the above-mentioned Exemplified Compound Black 7 were mixed at a mixing ratio of 80/20, and methanol/1, A recording layer gold film having a thickness of 700× was formed by coating with a spinner on a solution dissolved in 2-dichloroethane (8/2 weight ratio).

CH3CHs Example 2 In Example 1, it was used in the above-mentioned exemplified compound A6' at the exemplified hardware store in the 70s, and the mixing ratio of the dye and the compound was 'e75/
A recording medium was produced in the same manner as in Example 1 except that the number of particles was changed to 15.

Example 3 A recording medium was entirely prepared in the same manner as in Example 2 except that the above-mentioned Exemplified Compound A10 was used in place of Exemplified Compound &7.

Example 4 In Example 1, the above-mentioned exemplified compound Alt was used as exemplified compound A70, and the mixing ratio of the dye and the compound was changed. -70/
Recording media were tabulated in the same manner as in Example 1, except that the sample size was 30.

”・Example 5 In Example 2, the following formula (2) was substituted for the dye of formula (1).
A recording medium was produced in the same manner as in Example 2 except that the dye was used.

Comparative Example 1 A recording medium tube was prepared in the same manner as in Example 1, except that compounds of M=Cu, R1, R2, Rs, and R4=H in the general formula shown above were used in Example 1 for the exemplified hardware store in its 70s. Created.

Comparative Example 2 In Example 1, M""Cu s R1, R2, R5, R4"" in the general formula shown above instead of the exemplified compound black 70
A recording medium was produced in the same manner as in Example 1 except that compound F was used.

Comparative Example 3 A recording medium tube was produced in the same manner as in Example 1, except that a compound of M=MnSR1, R2, R5, R4=H in the general formula shown above was used for the exemplified compound Mu 70s.

Comparative Example 4 In Example 1, a recording layer was formed using only the dye of formula (1).

Comparative Example 5 In Example 5, a recording layer was formed using only the dye of formula (2).

Each recording medium tabulated in the above examples and comparative examples has a wavelength of 7.
Information is written and reproduced from the substrate side using a 90 nm semiconductor laser beam at a recording frequency of α5 MH2% and a KM speed of 1.5 m/sec, and the reproduced waveform is spectral analyzed (scanning filter, bandwidth 10KH2) to obtain C/ N
l Measured well. Further, the same recording medium was irradiated with tungsten light of 54,000 lux for 20 hours to perform an experiment to accelerate reproduction deterioration, and then the reflectance and C/Nl were measured. Note that the reflectance was measured from the substrate side. The results are summarized in the table below. Note that the reflectance is a value on a flat surface, not on a groove portion.

Claims (1)

[Scope of Claims] A recording medium comprising a recording layer containing a polymethine dye as a main component directly or through an undercoat layer on a substrate, and further providing a protective layer thereon as necessary, wherein the recording layer contains There are general formulas ▲ mathematical formulas, chemical formulas, tables, etc.
R_1, R_2, R_3 and R_4
at least one of -SO_2N(R_5)_2 and M is Cu, V, VO_2, Pb, Ni, SnCl
_2, Mn, Zn, or Sn, and a substituent other than R_5 may be present on the aromatic ring in the above formula.] An optical information recording medium characterized by containing a compound represented by the following.