JPH05234134A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To prevent the surface electrification of a substrate by forming an electric conductive transparent thin film as a first layer and an SiOx film or an org. protective film as a second layer on one side of the substrate with a recording layer formed on the other side. CONSTITUTION:A recording layer 2 is formed on one side of a substrate 1 and a protective layer 3 is further formed on the recording layer 2. A hard coat layer 4 consisting of an electric conductive transparent thin film 4a as a first layer and an SiOx film or an org. protective film 4b as a second layer is formed on the other side of the substrate 1. The thin film 4a is usually formed by a vacuum film forming process such as sputtering or vapor deposition and this film 4a can remove static electricity generated on the substrate 1 during molding or can prevent the electrification of the substrate 1 during handling.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical information recording medium, and more particularly to an optical information recording medium for writing and / or reading a recording by using a laser beam.

[0002]

2. Description of the Related Art Optical information recording media in conventional optical moving image discs (LD), optical audio discs (CD), writable discs, etc. are made of metal such as polycarbonate resin or acrylic resin on a plastic substrate.
Alternatively, a recording layer including a dye or the like is generally provided. Further, in order to protect the recording layer from adhesion of dirt, scratches, dust, etc., a protective layer may be provided on the recording layer, or the surface of the recording layer may be enclosed between the substrate and the recording layer via air, a so-called It is known to have an air sandwich structure.

However, such a structure is provided only for the purpose of protecting the recording layer, and an obstacle caused by the outer surface itself of the recording medium which is in contact with the atmosphere, that is, light scattering of the reading laser, dust and dust, There are often problems such as a read error and a tracking error due to a scratch or the like, a malfunction of an electric circuit due to charging of a substrate which induces adhesion of dust and dust, and a damage of a semiconductor laser used for recording and reproducing.

5 and 6 are configuration diagrams of a conventional optical information recording medium. In the drawings, 11 is a substrate, 12 is a recording layer, 13 is a protective layer, 14 is a hard coat layer, and 15 is an adhesive layer. .. FIG. 5 is a diagram showing a structure with a protective layer, in which the recording layer is provided on only one side of the recording medium. That is, the recording layer 12 is formed on the substrate 11.
And a protective layer 13 is further provided on the recording layer 12. A hard coat layer 14 is provided on the opposite side of the substrate. FIG. 6 is a diagram showing a close sandwich structure,
Recording layers are provided on both sides of the recording medium. That is, the recording layers 12 provided on the upper substrate and the lower substrate are provided so as to correspond to each other via the adhesive layer 15. Hard coat layers 14 are formed on both sides of the outer surface of the substrate 11.

[0005]

[Object] The present invention has been made in view of the above-mentioned circumstances, and protects the outer surface of the optical information recording medium on the laser light irradiation side, prevents the charging of the substrate, and further prevents the reflection of light on the substrate surface. By realizing it at the same time, the reading error due to the light scattering of the reading laser and the reading error and tracking error due to the adhesion of dust and dust are prevented,
At the same time, to provide an optical information recording medium having a surface protection effect, and to provide an optical information recording medium capable of preventing damage to a semiconductor laser and circuit malfunction due to static electricity and improving reliability of a memory system. It was made for that purpose.

[0006]

In order to achieve the above object, the present invention provides (1)
At least a recording layer and / or a reproduction layer on the substrate,
In an optical information recording medium for writing and / or reading information by laser light, an outer surface portion irradiated with laser light to be focused on the recording layer,
A first layer made of a transparent conductive thin film provided from the substrate side toward the atmosphere layer side, and SiOx formed on the first layer
A second layer comprising a film or an organic protective film, and (2) the surface of the substrate on which the transparent conductive thin film is formed is smaller than the surface on which the SiOx film or the organic protective film is formed, Alternatively, the organic protective film is directly adhered to the substrate on the inner and outer peripheries of the substrate, and further, (3) the transparent conductive thin film is exposed on the inner perimeter of the substrate, and the supporting metal portion of the recording medium at the time of recording or reproducing. And (4) in (1), (2) or (3) above, the transparent conductive thin film is an indium oxide-based, tin oxide-based, zinc oxide-based, oxidized Consists of a compound semiconductor such as cadmium-based or zinc sulfide, and further (5)
In (4) above, the transparent conductive thin film is a thin film of 300 Å or less, and (6) above (1),
In (2) or (3), the transparent conductive thin film is
A metal such as gold, silver, palladium, or aluminum, and an alloy thereof; and (7) in (6), the transparent conductive thin film is a thin film of 200 Å or less, and ( 8) In any one of (1) to (7) above, the transparent conductive thin film exhibits a resistance value of 10 ⁹ Ω / □ or less, and (9) Any of (1) to (8) above. In the above, the organic protective film is made of an ultraviolet curable resin, and further, (10) in any one of the above (1) to (8), the film is continuously formed in vacuum. It is a thing. Hereinafter, description will be given based on examples of the present invention.

FIG. 1 is a block diagram for explaining one embodiment of an optical information recording medium according to the present invention, in which 1 is a substrate and 2 is a substrate.
Is a recording layer, 3 is a protective layer, 4 is a hard coat layer, 4a is a transparent conductive thin film, and 4b is a SiOx film or an organic protective film. A recording layer 2 is provided on the substrate 1, and a protective layer 3 is formed on the recording layer 2. A hard coat layer 4 is formed on the opposite side of the substrate 1. The hard coat layer 4
Is formed of a first layer made of a transparent conductive thin film 4a and a second layer made of a SiOx film or an organic protective film 4b.

At this time, it is sufficient that the transparent conductive thin film has a film thickness of 300 Å or less, and ITO is used as the transparent conductive thin film.
When a low resistance material such as (indium tin oxide film) is used, about 100 Å can sufficiently obtain the antistatic effect of the substrate. SnO ₂ or Z instead of this ITO film
Even if nO or the like is used, almost the same effect can be obtained.

The substrate is made of plastic resin such as polyvinyl chloride (PVC), polyolefin (APO, PMMA), polycarbonate (PC), etc., and the recording layer is made of metal such as Al (aluminum), Au, Te, Bi. , A dye, a magneto-optical recording layer, a phase change recording layer, etc., and has basically the same structure as a conventional optical information recording medium.
As the first layer, a transparent conductive thin film 4a transparent to the wavelength of the read / write laser is formed on the surface of the optical information recording medium including the substrate 1 and the recording layer 2 on the laser light irradiation side.

The transparent conductive thin film 4a is made of indium oxide, tin oxide, zinc oxide,
Transparent conductive thin film of metal oxide such as cadmium oxide,
It is preferable to use an inorganic transparent conductive thin film having a relatively low resistance such as zinc sulfide, zirconium oxide, titanium oxide, cerium oxide, etc., which is usually formed by a vacuum film forming process such as a sputtering method or a vapor deposition method. Done. This transparent conductive thin film makes it possible to eliminate static electricity generated on the substrate during molding of the substrate, or prevent electrostatic charge on the substrate during handling.

As a protective layer for the first layer, a SiOx film or an organic protective film 4b as a second layer on the first layer.
To form. Similar to the transparent conductive thin film, the SiOx film is formed by a vacuum film forming process such as a sputtering method or a vapor deposition method. The surface is cured by the SiOx film, and an antireflection effect can be obtained by adjusting the refractive index. The organic protective film is made of an acrylate type, a methacrylate type, an epoxy type, or the like, and is cured by ultraviolet irradiation or the like, and has an effect of protecting the surface of the plastic resin. The hard coat layer having the above-mentioned two-layer structure simultaneously prevents the substrate from being charged and protects the substrate surface. Both of these film formations are performed by a vacuum process, but the adhesion and reliability are improved by successively performing the transparent conductive thin film and the SiOx film in this order in a vacuum.

FIG. 2 is a view showing another embodiment of the optical information recording medium according to the present invention, and the reference numerals in the drawing are the same as those in FIG. When the adhesiveness between the substrate 1 and the transparent conductive thin film 4a is not sufficient, the substrate 1 and the SiOx film or the organic protective film 4 in the A portion on the inner peripheral side and the B portion on the outer peripheral side of the substrate 1 are
It has a structure in which it is directly bonded to b. With this structure, the SiOx film or the organic protective film 4b can have an effect of suppressing the transparent conductive thin film 4a. Further, by applying the above structure even when the adhesion between the substrate 1 and the transparent conductive thin film 4a is good, further reliability can be obtained.

FIG. 3 is a view showing a state in which the optical information recording medium according to the present invention is set in a drive. In the figure, 5 is a hub diameter, 6 is a hole, 7a is a cut portion of a transparent conductive thin film, and 7b is a transparent conductive film. The thin film exposing hole 7c is an inner peripheral exposed portion of the transparent conductive thin film. By providing a structure in which a part of the transparent conductive thin film 4a is in contact with the metallic chucking portion of the drive, a grounding effect is obtained, and charging due to friction with air during rotation of the recording medium is more effectively performed. It can be prevented.

FIGS. 4A to 4C are diagrams showing the results of measuring the surface potential of various recording medium structures. Figure (a) is a polycarbonate (PC) substrate only, Figure (b) is a polycarbonate (PC) substrate provided with an organic protective film made of an acrylate resin, Figure (c)
Is a polycarbonate (PC) substrate on which an indium oxide-based transparent conductive thin film and an organic protective film made of an acrylate-based resin are sequentially laminated. After each surface potential is left at room temperature (25 ° C.) for one year, It is the result of measuring the surface potential of.

As a result of surface observation, stains are locally attached to a portion of the PC substrate of FIG. 5A where the surface potential is very high, and the medium of FIG. It was slightly dusty overall. On the other hand, Figure (c)
The recording medium of No. 2 had a much smaller amount of dust attached than that in the case of FIG. 6 (b), and there was almost no difference from the initial state. From these experimental results, it can be seen that the use of the optical information recording medium of the present invention can sufficiently obtain the antistatic effect on the substrate. In the present invention, due to the conductive effect of the transparent conductive thin film, it is possible to prevent the substrate itself from being charged. However, as an organic protective film, a conductive filler, a surfactant or the like may be mixed so that 10 ¹² If a material having a surface resistance of Ω / □ or less is used, it becomes a more effective means for preventing the electrification of the substrate surface.

[0016]

As is apparent from the above description, according to the present invention, the first layer made of the transparent conductive thin film and the second layer made of the SiOx film or the organic protective film are provided on the opposite side of the substrate provided with the recording layer. Since it is provided, the surface of the substrate can be prevented from being charged, and the effect of protecting the surface can be obtained, thereby improving the reliability of the optical information recording medium.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of an optical information recording medium according to the present invention.

FIG. 2 is a configuration diagram for explaining another embodiment of the optical information recording medium according to the present invention.

FIG. 3 is a diagram showing a state in which an optical information recording medium is set in a drive.

FIG. 4 is a diagram showing measurement results of surface potentials for various recording medium structures.

FIG. 5 is a configuration diagram of a conventional optical information recording medium.

FIG. 6 is another structural diagram of a conventional optical information recording medium.

[Explanation of symbols]

1 ... Substrate, 2 ... Recording layer, 3 ... Protective layer, 4 ... Hard coat layer, 4a ... Transparent conductive thin film, 4b ... SiOx film or organic protective film.

Claims (3)

[Claims] 1. An optical information recording medium having at least a recording layer and / or a reproducing layer on a substrate for writing and / or reading information by a laser beam, which should be focused on the recording layer. A first layer made of a transparent conductive thin film provided from the substrate side toward the atmosphere layer side on the outer surface portion irradiated with laser light, and a SiOx film or an organic protective film formed on the first layer. An optical information recording medium, comprising: 2. The transparent conductive thin film formation surface on the inner and outer peripheries of the substrate is smaller than the SiOx film or organic protective film formation surface, and the SiOx film or the organic protective film adheres directly to the substrate on the inner and outer peripheries of the substrate. An optical information recording medium characterized in that. 3. The transparent conductive thin film is exposed on the inner circumference of the substrate so as to come into contact with the supporting metal portion of the recording medium during recording or reproduction.
The optical information recording medium described.