JPH06290488A - Reloadable optical information recording medium - Google Patents

Abstract

(57) [Summary] [Object] To provide a writable optical information recording medium in which the organic dye contained in the light absorption layer is prevented from being modified and the recording / reproducing characteristics are not deteriorated. [Structure] A light-transmitting substrate and a light-transmitting oxide film are provided on one surface side of a light absorption layer containing an organic dye, and a reflection layer is provided on the other surface side of the light absorption layer. The translucent oxide film may be laminated on either the front or back surface of the translucent substrate either directly or through another layer, or directly or on the surface of the light absorbing layer on the translucent substrate side. You may laminate | stack via it. However, it is preferable to use a deoxidized translucent substrate, except when the translucent oxide film is directly laminated on the surface of the light absorption layer on the translucent substrate side.

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 FIG. 5 is a partial sectional view of an example of a conventional writable optical information recording medium. As shown in the figure, an optical information recording medium 10 includes a transparent substrate 12 and a transparent substrate 1.
2, a light absorption layer 14 that is laminated on one surface and absorbs the recording laser light, and an enhancement layer 16 that is laminated on the light absorption layer 14 and is transparent to the wavelength of the reproduction laser light. And a reflective layer 18 which is laminated on the enhancement layer 16 and reflects the laser light for reproduction, and a protective layer 20 which is laminated on the reflective layer 18.

When this optical information recording medium 10 is irradiated with a recording laser beam, the organic dye contained in the light absorbing layer 14 is changed and the optical phase of the light absorbing layer 14 is changed, whereby information is recorded. Will be recorded.

[0004]

By the way, in the conventional optical information recording medium, when the light is exposed to light for a long time, the organic dye contained in the light absorbing layer is modified with the passage of time, There is a problem that the reflectance and the recording / reproducing characteristics deteriorate.

An object of the present invention is to provide a writable optical information recording medium which prevents the organic dye contained in the light absorbing layer from being modified and prevents the reflectance and recording / reproducing characteristics from deteriorating. To do.

[0006]

In order to solve the above-mentioned problems, a writable optical information recording medium according to the present invention comprises:
A light-transmitting substrate and a light-transmitting oxide film are provided on one surface side of the light absorbing layer containing an organic dye, and a reflecting layer is provided on the other surface side of the light absorbing layer.

Here, the translucent oxide film may be laminated on either the front or back surface of the translucent substrate directly or via another layer, or the surface of the light absorbing layer on the translucent substrate side. It may be laminated directly on or via another layer. However, it is necessary to use a deoxidized translucent substrate except when the translucent oxide film is directly laminated on the surface of the light absorption layer on the translucent substrate side.

The transparent oxide film may be formed by reactive sputtering. Further, the transparent oxide film may be an enhance layer which is transparent to the wavelength of the reproducing laser beam.

[0009]

In the above-described optical information recording medium, when the transparent oxide film is directly provided on the surface of the light absorption layer on the transparent substrate side, the transparent oxide film moves from the transparent substrate. Oxygen is absorbed and oxidized, or the light-transmitting oxide film serves as a barrier to block the supply of oxygen to the light-absorbing layer and modify the organic dye contained in the light-absorbing layer. do not do.

In the above-mentioned optical information recording medium,
When the translucent oxide film is provided on the surface that is back-to-back with the surface of the translucent substrate on the side of the light absorption layer, the translucent oxide film absorbs oxygen that has moved from the translucent substrate. Oxidation or the light-transmitting oxide film serves as a barrier prevents oxygen from penetrating into the light-transmitting substrate. Here, if the translucent substrate of the optical information recording medium is deoxidized, the oxygen concentration in the translucent substrate does not increase, and there is no supply of oxygen from the translucent substrate to the light absorbing layer. Therefore, the organic dye contained in the light absorbing layer is not modified.

[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, on one surface of the transparent substrate 12, a transparent oxide film 22, a light absorption layer 14, an enhancement layer 16, a reflection layer 18 and a protective layer 20 are laminated in this order. .

Here, examples of the translucent material forming the translucent substrate 12 include polycarbonate, acrylic resin, polyolefin, epoxy resin, glass and the like. Any material having a refractive index of 1.4 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 pregroove may be under any condition that is usually considered, but the depth is 50
It is preferably about 250 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 translucent oxide film 22, M _X O
_y (however, M is a metal element, x is 1 when M is Si, M
When Al is Al, a metal oxide represented by an arbitrary number determined by the kind of M, y is 0.3 to 3.8), such as 2, can be used. Such a metal oxide can be formed by reactive sputtering in an environment where the oxygen concentration and pressure are adjusted.

The transparent oxide film 22 has a wavelength of 780 n.
It is necessary to select a film thickness such that the light transmittance of m is 70% or more. Moreover, since the light transmittance varies depending on the type of oxide, the film thickness needs to be changed appropriately depending on the type of oxide. .

The transparent oxide film 22 is formed and coated by a method such as sputtering, vapor deposition, ion plating, EB vapor deposition, dry process such as CVD, wet process such as plating, spin coating of a metal dispersion liquid, or the like. be able to.

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 resin such as nitrocellulose, thermoplastic elastomer), 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, and the light absorption layer 16
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 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.

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 disk-shaped light-transmitting substrate 12 having spiral-shaped pregrooves 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 film thickness of 3 is formed on one surface of the transparent substrate 12.
The transparent oxide film 22 made of 0 nm SiO _x (x = 1.2) was formed by reactive sputtering. Note that x is 0.
5-3.2 is preferable. Further, the film thickness is allowable up to 2 to 500 nm.

Next, 1,1'dibutyl 3,3,3 ', 3' tetramethyl 4,5,4 'is formed on the transparent oxide film 22.
A diacetone alcohol solution of 5'dibenzoindica-bocyanine perchlorate (manufactured by Japan Photosensitive Dye Laboratory Co., Ltd .: NK3219) was applied by a spin coat method to form a light absorption layer 14 having a film thickness d _abs = 130 nm. Was formed.

Here, this diacetone alcohol solution was added to 0.65 g of 1,1 'diptyl 3,3,3', 3 '.
Tetramethyl 4,5,4'5 'dibenzointo dica-bocyanine perchlorate dissolved in 10 cc of diacetone alcohol was used.

Then, a polymer of monomethylsiloxane is applied onto the light absorption layer 14 by a spin coat method to form a film thickness d.
_ehs was formed enhancement layer 16 of 50nm.

Next, Au was sputtered on the enhancement layer 16 to form a reflection layer 18 having a film thickness of 100 nm.

Next, an ultraviolet curable resin was applied on the reflective layer 18 by a spin coating method and irradiated with ultraviolet rays to be cured to form a protective layer 20 having a film thickness of 10 μm.

Next, the optical information recording medium 1 obtained by the above method
When 0 was irradiated with light and the reflectance [%] with respect to the irradiation time was obtained, it was as shown by the curve a in FIG.

Irradiation of light to the optical information recording medium 10 is performed by a solar simulator (USHIO INC .: SSS-50).
1S-ER). The condition of light irradiation at this time was AM-1.

Comparative Example 1 An optical information recording medium 10 was made under the same conditions as in Example 1 except that the transparent oxide film 22 was not coated, and its reflectance was examined under the same conditions as in Example 1. As a result, it was as shown by the curve b in FIG.

Comparative Example 2 An optical information recording medium 10 was prepared under the same conditions as in Example 1 except that an oxide whose y was out of the range of 0.3 to 3.8 was used as the material of the translucent oxide film 22. When the reflectance was examined under the same conditions as in Example 1, the curve b in FIG.
The value was within the range of 4% indicated by.

When the reflectance [%] of Example 1 and the reflectance [%] of Comparative Examples 1 and 2 are compared, it can be seen that the deterioration of the reflectance [%] of Comparative Examples 1 and 2 is large. In the case of 1 and 2, oxygen in the atmosphere and oxygen contained in the light-transmissive substrate 12 move to the light-absorbing layer 14 side through the light-transmissive substrate 12, and this oxygen is contained in the light-absorbing layer 14. It seems that the organic dye contained in was modified.

Embodiment 2 FIG. 4 is a partial sectional view of another example of the optical information recording medium according to the present invention. In the optical information recording medium of this example, as shown in the figure, a transparent oxide film 22 is laminated on one surface of a transparent substrate 12, and a light absorbing layer is formed on the other surface of the transparent substrate 12. 1
4, the enhancement layer 16, the reflection layer 18, and the protective layer 20 are laminated in this order.

This optical information recording medium has a transparent oxide film 22.
An optical information recording medium not coated with is prepared in the same manner as in Example 1, and the optical information recording medium is placed in a vacuum container,
The film was exposed to a vacuum for 24 hours, and then the transparent substrate 12 of this optical information recording medium was coated with the transparent oxide film 22 by reactive sputtering.

When the deterioration of the reflectance of this optical information recording medium was examined under the same conditions as in Example 1, it was found to be exactly the same as in Example 1. From this result, it can be seen that the optical information recording medium of Example 2 is improved in optical deterioration in exactly the same manner as the optical information recording medium of Example 1.

[0038]

According to the present invention, the supply of oxygen to the light absorbing layer is blocked by the translucent oxide film, so that the organic dye contained in the light absorbing layer is prevented from being modified and the optical information recording is performed. There is an effect that the optical deterioration of the recording / reproducing characteristics of the medium 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.

FIG. 3 is a graph showing the relationship between the reflectance and the elapsed time of the optical information recording media of Example 1 and Comparative Example 1.

FIG. 4 is a partial cross-sectional view of another example of the optical information recording medium according to the present invention.

FIG. 5 is a partial cross-sectional view of an example of a conventional writable optical information recording medium.

[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 Translucent Oxide Film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chiharu Tsukamoto 6-16-20 Ueno Taito-ku, Tokyo Taiyo Induction Co., Ltd.

Claims (5)

[Claims] 1. A writable material having a light-transmitting substrate and a light-transmitting oxide film on one surface side of a light absorbing layer containing an organic dye, and a reflecting layer on the other surface side of the light absorbing layer. Optical information recording medium. 2. The optical information recording medium according to claim 1, wherein the light-transmissive oxide film is directly laminated on a surface of the light-absorption layer on the light-transmissive substrate side, which is writable. Optical information recording medium. 3. The optical information recording medium according to claim 1, wherein the translucent substrate is deoxidized, and the surface of the translucent substrate on the side of the light absorbing layer is a surface of the translucent substrate. A writable optical information recording medium, characterized in that the translucent oxide film is laminated directly or via another layer on the surfaces facing each other. 4. The writable optical information recording medium according to claim 2, wherein the translucent oxide film is an enhance layer transparent to the wavelength of the reproducing laser beam. . 5. The writable optical information recording medium according to any one of claims 1 to 4, wherein the transparent oxide film is formed by reactive sputtering.