JP3115088B2 - Optical information recording medium provided with silicon hydride film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium for recording, reproducing, and erasing information using a laser beam.

[0002]

2. Description of the Related Art A substrate for supporting a recording layer in an optical information recording medium is generally formed of a dielectric resin such as polycarbonate, glass, and 2P (photopolymer) resin, and thus is easily charged. When the optical information recording medium is charged, minute dust and dirt adhere to the reading surface side surface of the recording medium due to static electricity and hinder reproduction and recording of information. In addition, the charged charge may cause a malfunction of the electronic circuit. For the purpose of preventing such an optical information recording medium from being charged, it has been proposed to provide an antistatic film on the reading side surface of the optical information recording medium. Further, when dust adhering to the substrate surface is cleaned with a cloth or the like, since the surface hardness of the polycarbonate substrate or the like is low, the substrate is scratched, which hinders recording and reproduction of information. As described above, the reading surface side surface of the optical information recording medium preferably has both an antistatic function and a high surface hardness. It is also important to have an anti-reflection function to increase the reproduction output by effectively using the incident laser light.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and provides a highly reliable optical information recording medium in which dust and adhesion due to static electricity are prevented. The purpose is to:

[0004]

The present invention relates to an optical information recording medium comprising at least a transparent substrate and a recording layer and irradiating a laser to perform recording and reproduction, wherein an antistatic function, an antireflection function and a high surface By providing a silicon hydride film having hardness, the above-mentioned problem was solved. That is, in an optical information recording medium comprising at least a transparent substrate and a recording layer and performing recording and reproduction by irradiating a laser beam, an optical gap of 2.1 eV is formed on the recording and reproduction side surface of the recording medium.
An optical information recording medium provided with the above silicon hydride film, and preferably, the silicon hydride film has an active conductivity, and the value is 1 × 10 at room temperature.
^-13 S / cm or more. In the present invention,
The silicon hydride film needs to be provided at least on the recording / reproducing side surface of the recording medium, but the object to be processed is not limited to the surface, and the surface of the medium that comes into contact with the other atmosphere, for example, a protective surface It may be provided in a layer. Further, it may be provided on an intermediate layer of the medium, for example, an undercoat layer. When such an intermediate layer is provided, static electricity generated at the time of manufacturing the medium can be prevented. Silicon hydride that constitutes the silicon hydride film is an inorganic material composed of silicon and hydrogen.By changing the hydrogen content and the bonding mode, the optical characteristics, electric characteristics, and mechanical characteristics can be changed to some extent. The film can be formed preferably by decomposing silane gas and hydrogen gas using ECR plasma CVD.

As the transparent substrate, a synthetic resin such as polycarbonate, acrylic, epoxy, PMMA (polymethyl methacrylate), glass, or a 2P substrate is used.

[0006] The recording layer is formed by forming pits and recording data by means of deforming, sublimating, evaporating or denaturing the recording layer by irradiating a laser beam, or by using magneto-optics. Is mentioned. Examples of the former include a metal layer such as Te, Bi, and Mn, and a dye layer such as cyanine, merocyanine, and phthalocyanine. As the recording material using the latter magneto-optical effect, GdCo,
TbFe, TbFeCo, TbDyFe, TbDyFe
Co alloy and the like. These are all amorphous,
It has an easy axis of magnetization in a direction perpendicular to the film surface. The thin film can be formed by sputtering or electron beam evaporation. Further, the recording layer may be a recording material utilizing other phase change, such as a recording material utilizing a phase change between crystal and amorphous.

Although the optical information recording medium of the present invention basically has the above-mentioned transparent substrate and recording layer, it may have other layers as required, for example, the following layers. On one or both sides of the substrate, especially on the substrate surface on the side where the recording layer is provided, for the purpose of improving flatness, improving adhesion to the recording layer, improving sensitivity due to a heat insulating effect, and preventing deterioration of the recording layer. , An undercoat layer may be provided. In addition, a pre-groove layer can be provided as needed. This pre-groove layer is made of, for example, a radiation-curable resin, an electron beam,
It can be formed by irradiating ultraviolet rays or the like. In particular, as a recording material using the magneto-optical effect, a film (RE-TM film) in which a transition metal and a rare earth metal are combined is susceptible to oxidative corrosion.
Further, since the magneto-optical effect such as the force-effect and the Faraday effect of the RE-TM film itself is not large, a dielectric film which is transparent to laser light and has a large refractive index as a protective film on one or both surfaces of the RE-TM film, That is, it is preferable to provide one having the function of an enhancement film.

Further, in order to increase the reflectance of the optical information recording medium, it is preferable to provide a metal film as a reflection film. For example, gold, silver, aluminum or an alloy containing these may be deposited by means of vapor deposition, sputtering or the like. Can be formed.

It is desirable to provide a protective layer formed of a resin having excellent impact resistance on the reflective film. For example, an ultraviolet curable resin is applied by a spin coating method, and cured by irradiating ultraviolet rays. Form.

Hereinafter, description will be made based on the illustrated embodiment.
FIG. 1 shows a magneto-optical disk using a magneto-optical recording magnetic material for a recording layer. However, as described above, the optical information recording medium of the present invention is not limited to the case where a magneto-optical recording magnetic material is used for the recording layer. On the transparent substrate 1, a first dielectric protection layer 2, a magneto-optical recording layer 3, a second dielectric protection layer 4, a metal reflection layer 5, and an organic protection film 6 are formed in this order. A silicon hydride film 7 having high hardness and an antistatic function is formed on the surface. The first dielectric protection layer 2 and the second dielectric protection layer 4 are provided for protecting the magneto-optical recording layer 3 from oxidative corrosion due to H ₂ O, O ₂ or the like, or for enhancing the force-rotational angle. As a material, SiNx, SiOx, In ₂ O ₃ or the like is used. It is preferable to use a TbDyFeCo alloy as the magneto-optical recording layer 3, but the present invention is not limited to this. The metal reflection layer 5 is provided to reflect an incident laser beam and bring about an enhancement effect, and a metal having a high reflectivity such as Al or Au is used. The organic protective film 6 serves to prevent corrosion of each layer laminated below the metal reflective layer 5, and is made of an ultraviolet curable resin, a thermoplastic resin, or the like.

[0011]

EXAMPLE A silicon hydride film having the characteristics shown in Table 1 was coated on a recording / reproducing side substrate surface of an optical information recording medium by EC.
The film was formed under the following film forming conditions using an R plasma CVD method. Table 1 shows each characteristic of the silicon hydride film used in each example. The ECR plasma CVD method is used for the film formation method. The main film forming conditions are: SiH ₄ １〜1 to ₄ sccm H ₂ 〜4 to 8 sccm Pressure −４2.5E-4 to 7.3E-4 Torr Power ４００400 to 600 W Substrate temperature ７５75 to 150 ° C. Surface reflection In order to prevent this, the thickness is controlled and determined. Each configuration of the magneto-optical recording medium in the first to third embodiments has the configuration shown in Table 2. First
The dielectric protective layer 2 is made of a silicon nitride film having a refractive index of 2.20 at 900 A, and the magneto-optical recording layer 3 is made of Dy ₁₅ Tb ₇ Fe.
₇₀ Co ₈ as 200 A, as the second dielectric protection layer 4, a silicon nitride film with a refractive index of 2.20 as 300 A, and a metal reflection film 5
In this case, 500 A of aluminum and 1 μm of the ultraviolet curing resin 6 are laminated. The reflectivity, surface hardness, and BER (bit error rate) before and after the dust test were evaluated for the magneto-optical recording medium manufactured as described above, and the results are shown in Table 3. As a comparative example, an optical information recording medium having a configuration shown in Table 2 without a silicon hydride film was subjected to the same evaluation test, and the results are shown in Table 3. (Below)

[Table 1]

[Table 2] 1) Silicon hydride film of Example 1 of Table 1 2) Silicon hydride film of Example 2 of Table 1 3) Silicon hydride film of Example 3 of Table 1 (hereinafter blank)

[Table 3]

[0012]

The optical information recording medium of the present invention can prevent dust from adhering to the surface of the recording medium by providing a silicon hydride film having an antistatic effect on its surface, particularly on the substrate surface on the recording / reproducing side. Also, the possibility of damaging the disk even if the surface is cleaned with a cloth or the like can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a cross-sectional view of one configuration example of an optical information recording medium of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transparent substrate 2 first dielectric protective layer 3 magneto-optical recording layer 4 second dielectric protective layer 5 metal reflective layer 6 organic protective film 7 silicon hydride film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI G11B 11/105 531 G11B 11/105 531H 546 546F (58) Investigated field (Int.Cl. ⁷ , DB name) G11B 7/24 G11B 7/26 G11B 11/105

Claims (5)

(57) [Claims] 1. An optical information recording medium comprising at least a transparent substrate and a recording layer, wherein a silicon hydride film is provided on a recording / reproducing side surface of the recording medium. 2. An optical information recording medium comprising at least a transparent substrate and a recording layer, wherein a silicon hydride film is provided on at least a surface of the recording medium which is in contact with the atmosphere. 3. The optical information recording medium according to claim 1, wherein the silicon hydride film has an optical gap of 2.1 eV or more. 4. The silicon hydride film exhibits an active conductivity, the value of which is 1 × 10 ⁻¹³ S / cm or more at room temperature, and the optical gap is 2.1 eV or more.
Or the optical information recording medium according to 2. 5. The optical information recording medium according to claim 1, wherein the silicon hydride film is formed by decomposing a silane gas and a hydrogen gas by using an ECR plasma CVD method.