JPH06282874A - Writable optical information recording medium - Google Patents

Abstract

PURPOSE:To provide an optical information recording medium where adhesion property between an enhancement layer and a reflection layer is improved, recording characteristics, especially jitter performance, are improved, and durability is improved. CONSTITUTION:In the recording medium with a light transmission substrate 12 at one surface side of a light absorption layer 14 containing an organic coloring matter, a reflection layer 18 consisting of a metal at the other surface side of the light absorption layer 14, and a transparent enhancement layer 16 for the wavelength of laser beam for reproduction between the light absorption layer 14 and the reflection layer 18, the enhancement layer 16 and the reflection layer 18 are adhered via an adhesive layer 22. An organic metal crosslinking agent or a coupling agent is desirable as the material of the adhesive layer 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a light absorbing layer containing an organic dye with a recording laser beam on which information is superimposed to form a pit having an optical phase difference with a background portion. The present invention relates to a writable optical information recording medium.

[0002]

2. Description of the Related Art Various writable optical information recording media have been proposed. The applicant for this patent is
By improving such a writable optical information recording medium, R
Compact disc (C which is an OM type optical information recording medium
As a writable optical information recording medium which can be adapted to the standard of D), the one disclosed in JP-A-2-87342 is proposed.

In this writable optical information recording medium, an enhancement (e) between the light absorbing layer and the reflecting layer is transparent (imaginary part of complex refractive index k _ehs = 0) to the wavelength of the reproducing laser beam.
nhance) layer is provided. Since this writable optical information recording medium is provided with such an enhancement layer between the light absorption layer and the reflection layer, it has a feature that the reflectance of the reproducing laser light can be as high as 70% or more. There is.

[0004]

However, in this writable optical information recording medium, since the reflective layer is made of metal,
The binding force between the enhancement layer and the reflection layer may be small and non-uniform, and when such a portion is irradiated with the recording laser light, the irradiated portion (pit portion)
In this case, heat conduction may occur unevenly, the reflecting layer may be deformed unevenly, and recording characteristics, particularly jitter may deteriorate.

Further, in this writable optical information recording medium, since the reflection layer is made of metal, the binding force between the enhancement layer and the reflection layer is small, and when a large external force acts, or in a hot and humid environment. There is a risk of peeling between the enhance layer and the reflective layer when exposed to the light for a long time.

The present invention has been made in order to solve the above-mentioned problems, and improves the adhesiveness between the enhance layer and the reflective layer to improve the recording characteristics, particularly the jitter, and the writing with improved durability. An object is to provide a possible optical information recording medium.

[0007]

In order to solve the above-mentioned problems, a writable optical information recording medium according to the present invention comprises:
The light absorbing layer containing an organic dye has a translucent substrate on one surface side, the other surface side of the light absorbing layer has a reflective layer made of metal, and the light absorbing layer and the reflective layer In the writable optical information recording medium having the enhance layer transparent to the wavelength of the reproducing laser beam between the two, the enhance layer and the reflective layer were adhered via the adhesive layer.

Here, as the material of the adhesive layer, an organic metal crosslinking agent or a coupling agent such as a titanate coupling agent or a silane coupling agent can be used.

[0009]

In the present invention, since the enhancement layer and the reflection layer are adhered to each other via the adhesive layer, the enhancement layer and the reflection layer are firmly adhered to each other, and when the recording laser beam is irradiated, the irradiation is performed. In the portion (pit portion), heat conduction between the enhancement layer and the reflection layer occurs uniformly, and the reflection layer deforms uniformly.

Further, according to the present invention, since the enhancement layer and the reflection layer are adhered to each other via the adhesive layer, the enhancement layer and the reflection layer are firmly adhered to each other and a large external force is applied, or high temperature is applied. Even when exposed to a humid environment for a long time, there is no possibility of peeling between the enhance layer and the reflective layer.

[0011]

1 is a partially cutaway perspective view of an example of an optical information recording medium according to the present invention, and FIG. 2 is an enlarged view of portion A in FIG. As shown in the figure, the light absorbing layer 14, the enhancing layer 16, the reflecting layer 18, and the protective layer 2 are formed on one surface of the transparent substrate 12.
0 is laminated in this order. Then, the enhancement layer 16 and the reflection layer 18 are adhered to each other via the adhesive layer 22.

Here, as the material of the transparent substrate 12,
Examples thereof include polycarbonate, acrylic resin, polyolefin, epoxy resin, glass, and the like, and materials other than these also have a refractive index of 1.
Any material having an impact resistance of 4 to 1.6 and excellent impact resistance can be used.

The transparent substrate 12 can be molded by means such as injection molding. In addition, the transparent substrate 1
The 2 may have pregrooves formed in a spiral shape in advance. The pre-groove may have any conditions as long as it is usually considered, but the depth is 30
It is preferably ˜280 nm. The pre-groove is generally formed by pressing a stamper when manufacturing the transparent substrate 12 by injection molding, but the pre-groove is not necessarily limited to this method.

As the material of the light absorbing layer 14, a light absorbing organic dye is preferable. Specific examples of the light absorbing organic dyes include cyanine dyes, triarylmethane dyes, pyrylium dyes, phenanthrene dyes, tetradehydrocholine dyes, triarylamine dyes, squarylium dyes, croconic methine dyes, and phthalocyanine dyes. , And azurenium dyes,
Other light-absorbing organic dyes can also be used.

The light absorbing layer 14 may contain other dyes, resins (for example, thermoplastic resins such as nitrocellulose, thermoplastic elastomers), liquid rubber, and the like. Light absorbing layer 14
Is a translucent substrate 12 on which a pre-groove is formed by dissolving the above-described dye and any additive in an organic solvent (for example, alcohol, acetylacetone, methyl cellosolve, toluene, etc.), or of the translucent substrate 12. Coated on top of the other layers coated above.

As the coating method in this case, vapor deposition, L
Examples of the method include the B method and the spin coating method.
The spin coating method is preferred because the layer thickness can be controlled by adjusting the concentration, viscosity, and drying rate of the solvent.

The enhancement layer 16 is made of, for example, SiO ₂ ,
Amorphous SiO, Si ₃ N ₄ , SiN, AlN, Z
It can be formed of an inorganic dielectric such as nS or an organic dielectric such as silicon resin. When the enhancement layer 16 is formed of an inorganic dielectric material, the raw material is sputtered on the light absorption layer 14 directly or through another layer. When the enhancement layer 16 is formed of an organic dielectric, the raw material liquid is spin-coated on the light absorption layer 14 directly or via another layer.

The film thickness d _ehs of the enhancement layer 16 is the real part n _abs of the complex refractive index of the light absorption layer 14, the film thickness d _abs of the light absorption layer 14, the real part n of the complex refractive index of the enhancement layer 16.
_ehs, the film thickness d _ehs and reproducing Les enhancement layer 16 - the value given by the wavelength of the laser light _{λ ρ = (n abs · d} abs
+ N _ehs · d _ehs ) ÷ λ is set so that 0.05 ≦ ρ ≦ 1.6.

As a material for the adhesive layer 22, a compound having adhesiveness to both the enhancement layer 16 and the reflection layer 5, for example, an organic metal cross-linking agent, a titanate coupling agent, a silane coupling agent or the like is used. However, an organic metal compound other than these may be used as long as it is a compound having adhesiveness to both the enhancement layer 16 and the reflection layer 5.

Examples of the organic metal cross-linking agent include TEA
T (manufactured by Mitsubishi Gas Chemical Co., Inc.), Ti triethanolamine, Ti (OC ₆ H ₁₃ ) ₄ , Ti (O i-C ₃ H
₇ ) ₄ , ALCH, hydroxytitanium oleate,
Examples include Citabond-50 (manufactured by Nippon Soda Co., Ltd.), Acetope Al (manufactured by Hope Pharmaceutical Co., Ltd.), and Algoma (manufactured by Kawaken Fine Chemical Co., Ltd.).

Examples of the titanate coupling agent include, for example, Plenact TTS (manufactured by Ajinomoto Co., Inc.), isopropyl triacryl titanate, titanium 4-aminobenzoate isostearate oxyacetate, di (dioctyl phosphate) ethylene titanate, tetraisopropyl di (diamine). Mention may be made of lauryl phosphate) titanate.

As the silane coupling agent, for example,
γ-methacryloxypropyltrimethoxysilane, N-
Examples include β (aminoethyl) γ-aminopropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, and γ-aminopropyltriethoxysilane.

The reflective layer 18 is preferably a metal film such as gold, silver, aluminum or an alloy containing these.
The metal film can be formed by means such as vapor deposition and sputtering. The reflective layer 18 may be coated with an oxidation resistant layer in order to prevent its oxidation.

In order to protect the reflective layer 18, it is preferable to form the protective layer 20 on the reflective layer 18 directly or via another layer. It is desirable that the protective layer 20 be formed of a synthetic resin having excellent impact resistance. For example, it is formed by applying an ultraviolet curable resin by a spin coating method and irradiating it with ultraviolet rays to cure it.

Example 1 First, a disc-shaped transparent substrate 12 having spiral pre-grooves was formed by an injection molding method. Here, polycarbonate was used as the material of the transparent substrate 12. The transparent substrate 12 has a thickness of 1.2 m.
m, outer diameter 120 mmφ, and inner diameter 15 mmφ. The pre-groove has a width of 0.8 μm, a depth of 0.08 μm and a pitch of 1.6 μm, and the diameter of the transparent substrate 12 is 46 to 117 m.
It was formed in the range of mφ.

Next, a diacetone alcohol solution of an organic dye was applied onto the transparent substrate 12 by spin coating to form the light absorbing layer 14.

Here, this diacetone alcohol solution contained 30 mg of 1,1'-diethoxyethyl 3,3.
3 ', 3' Tetramethyl 4,4'diethoxyindodicarbocyanine iodide and 20 mg of 1,1'-dibutyl 3,3,3 ', 3' tetramethyl 4,5,4 ',
5'dibenzoindodicarbocyanine perchlorate dissolved in 1 ml diacetone alcohol was used.

Next, SiO was sputtered on the light absorption layer 14 to form an enhancement layer 16 having a thickness of 40 nm.

Next, a hexane solution of hydroxytitanium oleate was spin-coated on the enhance layer 16 to form an adhesive layer 22 having a film thickness of 10 nm.

Next, Au is vapor-deposited on the adhesive layer 22,
The reflective layer 18 having a film thickness of 80 nm was formed.

Next, an ultraviolet curable resin was applied on the reflective layer 18 by a spin coating method, and this was irradiated with ultraviolet rays to be cured to form a protective layer 20 having a film thickness of 8 μm.

Next, a laser beam having a wavelength of 780 nm is applied to the optical information recording medium thus obtained at a linear velocity of 1.2 m / s.
It was irradiated with ec and a recording power of 6.0 mW to record an EFM signal. Then, a commercially available CD player (Aurex XR-V73, wavelength of reproduction light λ =
(780 nm), the reproduced signal has a jitter of 2
It was 2 ns.

Next, a durability test was carried out by holding for 1000 hours in an environment of a temperature of 70 ° C. and a humidity of 85%, and no peeling or deterioration of jitter was observed.

Comparative Example 1 The same experiment as in Example 1 was conducted except that the adhesive layer 22 was not provided between the enhance layer 16 and the reflective layer 18, and the same experiment as in Example 1 was conducted. It was 31 ns, and in the durability test, when viewed from the substrate side, the pattern was visible and could not be reproduced. It is considered that there is peeling at the interface.

Example 2 The same procedure as in Example 1 except that a silicone resin was used as the material for the enhancement layer 16, γ-aminopropyltriethoxysilane was used as the adhesive, and Al was used as the reflective layer 18. When the same experiment as in Example 1 was performed,
The reproduced signal had a jitter of 22 ns, and neither peeling nor deterioration of the jitter was observed in the durability test.

Comparative Example 2 The same experiment as in Example 2 was conducted except that the adhesive layer 22 was not provided between the enhance layer 16 and the reflective layer 18, and the same experiment as in Example 2 was carried out. It was 34 ns, and the jitter was 45 ns in the durability test.

Example 3 SiAlON was sputtered to form an enhance layer, and a hexane solution of ethyl acetoacetate aluminum diisopropylate was applied on the enhance layer to form an adhesive layer 22, and Al was sputtered and reflected. The same experiment as in Example 1 was carried out except that the layer 18 was formed. When the same experiment as in Example 1 was performed, the jitter of the reproduced signal was 26 ns, and neither peeling nor deterioration of the jitter was observed in the durability test.

Comparative Example 3 The same experiment as in Example 3 was conducted except that the adhesive layer 22 was not provided between the enhancement layer 16 and the reflective layer 18, and the same experiment as in Example 3 was carried out. It was 40 ns, and in the durability test, the aluminum film as the reflection layer 18 was found to be cracked.

[0039]

According to the present invention, when information is recorded by irradiating an optical information recording medium with a recording laser beam, heat conduction between the enhance layer and the reflective layer occurs at the irradiating portion (pit portion). It occurs uniformly and the reflective layer is uniformly deformed,
This has the effect of improving the recording characteristics of the optical information recording medium, especially the jitter.

Further, according to the present invention, since the enhancement layer and the reflection layer are firmly adhered to each other, even when a large external force is applied or when they are exposed to a hot and humid environment for a long time, etc. There is an effect that the optical information recording medium is free from the possibility of peeling between the enhancement layer and the reflection layer and the reliability is improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an example of an optical information recording medium according to the present invention.

FIG. 2 is an enlarged view of part A of FIG.

[Explanation of symbols]

 10 Optical Information Recording Medium 12 Translucent Substrate 14 Light Absorbing Layer 16 Enhance Layer 18 Reflective Layer 20 Protective Layer 22 Adhesive Layer

Claims (3)

[Claims] 1. A light-absorbing layer having an organic dye and a light-transmitting substrate on one surface side thereof, and a reflective layer made of a metal on the other surface side of the light-absorbing layer. In a writable optical information recording medium having an enhancement layer transparent to the wavelength of the reproducing laser beam between the reflection layer and the reflection layer, the enhancement layer and the reflection layer are bonded via an adhesive layer. And a writable optical information recording medium. 2. The writable optical information recording medium according to claim 1, wherein the adhesive layer comprises an organic metal cross-linking agent. 3. The writable optical information recording medium according to claim 1, wherein the adhesive layer comprises a coupling agent.