JPH06282869A - Writable optical information recording medium - Google Patents

Abstract

PURPOSE:To provide a writable optical information recording medium where recording/reproduction characteristics do not deteriorate by preventing modification of an organic coloring matter contained in a light absorption layer. CONSTITUTION:A light transmission substrate 12 and an oxygen nontransmission film with light transmission property are provided on one surface side of a light absorption layer containing an organic coloring matter and then a reflection layer 18 is provided on the other surface side of a light absorption layer 14. The oxygen non-transmission film may be laminated on either the front or rear surface of the light transmission substrate directly or via the other layer or may be laminated on the surface of the transmission light substrate side of the light absorption layer 14 directly or via the other layer. However, it is desirable to use the light transmission substrate 12 after it is deacidified.

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. 6 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 light reflection layer 18 which is laminated on the enhancement layer 16 and reflects the reproduction laser light, and a protective layer 20 which is laminated on the light reflection 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 recording / reproducing characteristics deteriorate.

It is an object of the present invention 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 recording / reproducing characteristics from deteriorating.

[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 oxygen-impermeable 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 oxygen impermeable film may be laminated on either the front or back surface of the transparent substrate directly or through another layer, or on the surface of the light absorbing layer on the transparent substrate side. You may laminate | stack directly or through another layer. However, it is necessary to use a deoxidized light-transmissive substrate except when the oxygen-impermeable film is directly laminated on the surface of the light-absorption layer on the light-transmissive substrate side.

As the translucent substrate, a substrate having oxygen impermeability may be used. Further, a material having oxygen impermeability may be used as the light absorption layer. Furthermore, an enhance layer transparent to the wavelength of the reproducing laser beam can be provided between the translucent substrate and the reflective layer to improve the recording / reproducing characteristics. In this case, oxygen is impermeable as the enhance layer. You may use what has a property. In either case, there is an advantage that it is not necessary to separately provide an oxygen impermeable film.

[0009]

In the above-described optical information recording medium, when the oxygen impermeable film is provided on the surface which is back-to-back with the surface of the transparent substrate on the side of the light absorption layer, the oxygen in the air is transferred to the transparent substrate. Permeation is blocked by this oxygen impermeable membrane. Here, since 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.

In the above-mentioned optical information recording medium,
When an oxygen impermeable film is provided between the light transmissive substrate and the light absorbing layer, the oxygen contained in the light transmissive substrate is prevented from moving to the light absorbing layer. The organic dye contained in the light absorption layer is not modified.

In the above-mentioned optical information recording medium,
When the translucent substrate, the light absorption layer or the enhancement layer has oxygen impermeability, migration of oxygen to the light absorption layer is blocked by this layer, and the organic dye contained in the light absorption layer is not modified. .

[0012]

Embodiment 1 FIG. 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 sectional view of part A of FIG. As shown in the figure, the light absorbing layer 1 is formed on one surface of the transparent substrate 12.
4, the enhancement layer 16, the reflection layer 18, and the protective layer 20 are laminated in this order, and the oxygen impermeable film 22 is laminated on the other surface of the transparent substrate 12.

Here, examples of the light-transmitting material forming the light-transmitting substrate 12 include polycarbonate, acrylic resin, polyolefin, and the like, and even synthetic resins other than these may have a refractive index for laser light. Is 1.4 ~
If it is 1.6 and has excellent impact resistance, it can be used. However, the transparent substrate 12 in this example needs to be deoxidized.

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 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 preferable because the layer thickness can be controlled by adjusting the concentration and the drying rate of the viscosity 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.

As the oxygen impermeable film 22, for example, polyvinylidene chloride (“Saran L545” manufactured by Asahi Kasei Corporation) is used.
C ", Kureha Chemical Industry Co., Ltd." Kureharon DO833S
)), A silicon compound (“Ceramica” manufactured by Nichibo Kenkyusho Co., Ltd.) and the like can be used, but other materials may be used as long as they have a very small oxygen transmission amount.

The film thickness of the oxygen impermeable film 22 is 25 μm.
Oxygen transmission rate is 300cc / m ² · day · at
When the film thickness is 25 μm, the oxygen permeation rate is 1000 cc / m ²
-Day / atm or less, the range of 100 to 1000 μm is preferable, and the amount of oxygen permeation is 3 when the film thickness is 25 μm.
If it is 000 cc / m ² · day · atm or less, 1 mm or more is preferable.

The oxygen-impermeable film 22 is formed by immersing the optical information recording medium in the raw material resin liquid, or by dropping the resin liquid on a rotating optical information recording medium for spin coating, or spraying the resin liquid. Can be covered by a method such as spraying.

Next, a specific manufacturing example of this optical information recording medium will be described. First, the disc-shaped translucent substrate 12 on which the spiral pre-groove was formed was formed by the 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 mm, an outer diameter of 120 mmφ, and an inner diameter of 15 mm.
It was φ. The pregroove has a width of 0.8 μm and a depth of 0.0
The transparent substrate 12 was formed to have a diameter of 46 to 117 mm and a pitch of 1.6 μm.

Next, 1,1'dibutyl 3,3,3 ', 3' tetramethyl 4,5,4'5 'is formed on the transparent substrate 12.
A diacetone alcohol solution of dibenzoindoca-bocyanine perchlorate (manufactured by Japan Photosensitive Dye Research Institute: NK3219) was applied by a spin coat method to form a light absorption layer 14 having a film thickness d _abs = 130 nm. did.

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, this optical information recording medium was placed in a vacuum container and exposed to a vacuum for 24 hours to remove oxygen contained in the transparent substrate 12.

Next, a resin liquid as a raw material of the oxygen impermeable film 22 was spin-coated on the light transmissive substrate 12 of this light transmissive substrate, and this was thermally cured to form the oxygen impermeable film 22.
As the material of the oxygen impermeable film 22, as described above, Saran L545C, Klehalon DO833S and ceramica were used.

Next, the optical information recording medium 1 obtained by the above method
When 0 was irradiated with light and the deterioration rate [%] was determined, it was as shown by the curves a to c in FIGS. 3 and 4. here,
Curve a shows the case where Saran L545C is used as the oxygen impermeable membrane 22, and curve b shows the oxygen impermeable membrane 22 as Krehalon DO8.
When 33S is used, the curve c shows the deterioration rate when ceramica is used as the oxygen impermeable film 22. The deterioration rate indicates the attenuation rate of the peak value of the absorption coefficient of the organic dye contained in the light absorption layer 14.

Irradiation of light to the optical information recording medium 10 is performed by a solar simulator (SSS-5 manufactured by USHIO INC.).
01S-ER). The condition of light irradiation at this time was AM-1. Further, the attenuation rate of the peak value of the absorption coefficient of the organic dye in the light absorption layer 14 was obtained using a spectrophotometer (U-4000 manufactured by Hitachi, Ltd.).

Comparative Example 1 An optical information recording medium 10 was prepared under the same conditions as in Example 1 except that the optical information recording medium 10 was not deoxidized under reduced pressure before being covered with the oxygen impermeable film 22. When the photodegradation was examined under the same conditions as in Example 1, the results were as shown by the curves d and e in FIG. Here, the curve d shows the deterioration rate when Saran L545C is used as the oxygen impermeable film 22, and the curve e shows the deterioration rate when Klehalon DO833S is used as the oxygen impermeable film 22.

When the deterioration rate [%] of Example 1 and the deterioration rate [%] of Comparative Example 1 are compared, the deterioration rate [%] of Comparative Example 1 is large. It is considered that the oxygen contained in the organic substrate 12 moved to the light absorption layer 14 side, and this oxygen modified the organic dye contained in the light absorption layer 14.

Comparative Example 2 An optical information recording medium 10 was prepared under exactly the same conditions as in Example 1 except that the oxygen impermeable film 20 was not coated. I used Saran L545C for 22), and when I examined its photodegradation,
The result is shown by the curve f in FIG.

When the deterioration rate [%] of Example 1 and the deterioration rate [%] of Comparative Example 2 are compared, the deterioration rate [%] of Comparative Example 2 is large. It is considered that the oxygen of the above reached the light absorption layer 14 through the transparent substrate 12, and this oxygen modified the organic dye contained in the light absorption layer 14.

Comparative Example 3 An optical information recording medium 10 was prepared under the same conditions as in Example 1 except that the transparent substrate 12 was not deoxidized under reduced pressure and the oxygen impermeable film 22 was not coated. When the photodegradation was examined under exactly the same conditions as in Example 1, the result was as shown by the curve g in FIG.

When the deterioration rate [%] of the comparative example 2 and the deterioration rate [%] of the comparative example 3 are compared, the deterioration rate [%] of the comparative example 3 is quickly reduced in the case of the comparative example 3. Translucent substrate 12
Oxygen contained in immediately reaches the light absorption layer 14,
It is considered that this oxygen modified the organic dye contained in the light absorption layer 14.

Embodiment 2 FIG. 5 is a partial sectional view of another example of the optical information recording medium according to the present invention. The optical information recording medium of this example has an oxygen impermeable film 2 on one surface of a transparent substrate 12, as shown in FIG.
2, the light absorption layer 14, the enhancement layer 16, the reflection layer 18, and the protective layer 20 are laminated in this order.

The optical information recording medium of this example has a transparent substrate 1
2 is different from the first embodiment in that the oxygen impermeable film 22 is laminated on the surface of the second light absorbing layer 14 side, but the contents of each layer itself are exactly the same as in the first embodiment. The manufacturing method of the optical information recording medium is different from that of the first embodiment in that the oxygen impermeable film 22 is first formed on the transparent substrate 12 and that the optical information recording medium 10 is not deoxidized.

The deterioration rate of the optical information recording medium 10 with respect to light irradiation was exactly the same as in the case of Example 1. From this result, it can be seen that the optical information recording medium of Example 2 is also improved in optical deterioration like the optical information recording medium of Example 1.

[0043]

According to the present invention, the supply of oxygen to the light absorbing layer is blocked by the oxygen impermeable film, so that the organic dye contained in the light absorbing layer is prevented from being modified and the optical information recording medium. There is an effect that the optical deterioration of the recording / reproducing characteristics 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 deterioration rates of the recording / reproducing characteristics of the optical information recording media of Example 1 and Comparative Example 1.

FIG. 4 is a graph showing the deterioration rates of the recording / reproducing characteristics of the optical information recording media of Example 1 and Comparative Examples 2 and 3.

FIG. 5 is a partial cross-sectional view of another example of the optical information recording medium according to the present invention.

FIG. 6 is a partial cross-sectional view of a conventional 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 Oxygen Impermeable Film

Claims (6)

[Claims] 1. A light-absorbing layer containing an organic dye, which has a light-transmitting substrate and a light-transmitting oxygen-impermeable film on one surface side, and a reflection layer on the other surface side of the light-absorbing layer. A writable optical information recording medium having the same. 2. The optical information recording medium according to claim 1, wherein the oxygen impermeable film is directly laminated on the surface of the light absorption layer on the side of the transparent substrate. 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 oxygen impermeable film is provided directly or via another layer on the surfaces opposite to each other. 4. A light-absorbing layer containing an organic dye has a light-transmitting substrate on one surface side, and a light-reflective layer on the other surface side of the light-absorbing layer, wherein the light-transmitting substrate is oxygen. A writable optical information recording medium having opacity. 5. A light transmissive substrate is provided on one surface side of the light absorbing layer containing an organic dye, and a reflective layer is provided on the other surface side of the light absorbing layer, wherein the light absorbing layer is oxygen-impermeable. A writable optical information recording medium characterized by having transparency. 6. A light transmissive substrate is provided on one surface side of a light absorbing layer containing an organic dye via an enhancement layer transparent to a wavelength of a reproducing laser beam, and the other side of the light absorbing layer is provided. 1. A writable optical information recording medium having a reflective layer on the surface side, wherein the enhance layer has oxygen impermeability.