JPH01176586A - optical information recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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.

[Prior art]

Until now, 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 derivative is provided on a substrate, but these have poor storage stability, low resolution, and low recording density. It has disadvantages such as low production conditions, 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, and because film formation can be done by coating, it is highly mass-producible and expected to be low cost. There are advantages such as being able to

Conventionally, it has been known to use a cyanine dye or merocyanine dye coating as the organic dye coating. However, recording layers composed of such dyes have poor heat and light stability, have problems with storage stability, and are susceptible to playback deterioration. An object of the present invention is to provide an information recording medium having an organic dye recording layer with excellent properties and improved reproduction deterioration.

〔composition〕

The above object is achieved by incorporating at least one compound represented by the following general formula into the recording layer of the optical information recording medium.

(In the above formula, R1 to R6 represent hydrogen, halogen, hydroxyl group, carboxyl group, or optionally substituted alkyl group, alkoxy group, aryl group, acyl group, or acyloxy group) Optical information recording medium of the present invention teeth,
Basically, it is constructed by providing a layer made of at least one compound selected from the compounds represented by the above general formula on a substrate, but if necessary, an undercoat layer may be provided between the substrate and the recording layer. A protective layer can be provided on top of the layer or 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. laminated structure)
You may also do so.

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 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 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) Recording layer The recording layer is capable of producing some optical change by irradiation with a laser beam and recording information based on the change, and its main component is composed of the above-mentioned dye compound.

Next, specific examples of dyes preferably used in the present invention are shown in the following table using the following structural formulas and substituents.

In order to improve recording characteristics and stability, the recording layer of the present invention may contain other dyes, such as phthalocyanine, tetrahydrocholine, dioxazine, triphetchazine, phenanthrene, anthraquinone (
indathrene)-based, cyanine (merocyanine)-based, croconium-based, pyrylium-based, azulene-based dyes, metals or metal compounds, such as In, Sn, Te, Bi
, AQ, Se, TaO2,5nO5AI Cd
, Zn, etc. may be dispersed therein, or may be laminated. In addition, the recording layer can contain a polymer material, a storage stabilizer (metal complex, phenolic compound), a dispersant, a flame retardant, a lubricant, a plasticizer, and the like. The thickness of the recording layer is 100 to 10 μm, preferably 200 to 2000 μm. As a method for forming the recording layer, solvent coating methods such as dip coating, spray coating, spinner coating, blade coating, roller coating, curtain coating, etc. can be used, as well as vapor deposition, CVD, sputtering, and the like.

(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 Sin, MgF2.5iO1T10□,
ZnO1TiN, SiN, etc., metals or metalloids such as Zn, Cu, S, Ni, Cr, Ge, Se,
Au-Ag, AQ, etc. can be used. For the purpose of (d), metals such as AΩ, Ag, etc., 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 for the purposes of (a) protecting the recording layer from scratches, dust, dirt, etc., (b) improving storage stability of the recording layer, and (c) improving reflectance. 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 dye according to the present invention can also be contained in the undercoat layer and the protective layer.

〔effect〕

The optical information recording medium of the present invention configured as described above is capable of recording and reproducing using long wavelength light such as a semiconductor laser, has improved thermal stability and optical stability, and has excellent storage stability and playability. It has little deterioration. Furthermore, pits can be formed in a good shape and a high C/N ratio can be obtained.

〔Example〕

The present invention will be further explained below with reference to Examples =8- However, the present invention is not limited only to these Examples.

Example 1 Polymethyl methacrylate (PM) with a thickness of 1 and 2 mm
MA) On a plate (diameter 130 mm), a helical group with a depth of 900 layers, a half-width of 0.4 μm, and a pitch of 1.6 μm was formed using acrylic photopolymer, and the compound No. 2 was added at I Thickness 9 under Torr
A recording layer was formed by vacuum deposition.

Next, a semiconductor laser beam with a wavelength of 790 nm is applied to this recording medium from the substrate side at a recording frequency of 0.7 MHz and a linear velocity of 2.1.
Information was written and reproduced at m/see, its spectrum analysis (scanning filter band @ 30 kHz) was performed, and the C ratio was measured. Furthermore, this same recording medium has 54
The C/N ratio was measured in the same manner after performing an accelerated regeneration deterioration test by irradiating with tungsten light of 000 lux for 6 hours.

Example 2 A recording medium was obtained in the same manner as in Example 1 except that the compound No. 5 was used as the dye, and its performance test was conducted.

Example 3 A tetrahydrofuran solution (0.5%) of Compound NoL3 was applied using a spinner onto the substrate of Example 1 to form a recording layer with a thickness of 750 mm, and its performance was tested.

Example 4 A recording medium was obtained in the same manner as in Example 3 except that the compound N015 was used as the dye, and its performance was tested.

Example 5 A recording layer having a thickness of 400 layers was formed in the same manner as in Example 1, and then 81 was vacuum evaporated to a thickness of 100 layers from another evaporation source to form a recording layer, and its performance was tested.

Example 6 Te was deposited on the substrate shown in Example 1.
After the recording layer was deposited to a thickness of 150 mm using the same method as in Example 2, a recording layer of a thickness of 400 mm consisting of the dye of compound Nα5 was provided, and its performance was tested.

Example 7 A recording layer was formed in the same manner as in Example 3, except that a mixture of the compound No. 13 and the stabilizer shown below at a weight ratio of 100:15 was used, and a performance test was conducted on the recording layer.

Example 8 A recording layer was formed in the same manner as in Example 7 except that the stabilizer was replaced with the one shown below, and its performance test was conducted.

((Bu)zNr〇--C)-N-C)-N(Bu)2
)2・SbF.

Comparative Example A recording layer was formed in the same manner as in Example 3 except that the following compound was used, and its performance test was conducted.

CI (3C113 The above results are summarized in the table below.

Table-2

Claims (1)

[Claims] (1) In an optical information recording medium in which a recording layer is provided directly or via an undercoat layer on a substrate, and a protective layer is further provided as necessary, at least one compound represented by the following general formula is contained in the recording layer. An optical information recording medium characterized by containing. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the above formula, R^1 to R^6 are hydrogen, halogen, hydroxyl group, carboxyl group, or optionally substituted alkyl group, alkoxy group, aryl group, acyl group) or acyloxy group)