JPH04345958A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To prevent such an inconvenient case where the dust, etc., stick on the surface of a base board with the charging and the reading/writing operations of information are effected. CONSTITUTION:A recording layer 2 is formed on one of both sides of a base board 1, and an inorganic antistatic layer 3 is formed on the other side of the board 1 respectively. The layer 3 touches a spindle bearing part 4 when an optical information recording medium is loaded to a driving device. Thus the electrostatic charge can be set free with high efficiency on the surface side of the board 1. Then it is possible to prevent such an inconvenient case where the dust, etc., stick on the surface of the board 1 with the charging end the reading/writing operations of information are effected.

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 and reproducing information using laser light.

0002

[Prior Art and Problems to be Solved by the Invention] The substrate that supports the recording layer in an optical information recording medium is generally made of a dielectric material such as polycarbonate or 2P resin (photopolymer), so it is easily charged. . When an optical information recording medium is charged, minute dust and dirt are deposited on the surface of the substrate on which the recording layer is not formed (hereinafter referred to as the outer surface) due to static electricity.
It adheres to the surface and obstructs the reading and writing of information, and
Charged charges cause electronic circuits to malfunction.

On the other hand, resin substrates such as polycarbonate, which are generally used as substrates, have low hardness on the outer surface and are prone to scratches. For this reason, if the outer surface is wiped or rubbed with dust or dirt adhered to it, scratches will easily occur, making it impossible to reproduce information. In particular, CDs (compact discs) are magneto-optical discs and WORMs (Write discs).
Since there is no cartridge case to protect the disc like the OnceRead Many) disc, scratches are likely to occur due to the above factors.

The present invention was made to solve the problems of the prior art as described above, and its purpose is to provide a highly reliable optical information recording medium that prevents the generation of static electricity and scratches. do.

[0005]

[Means for Solving the Problems] In order to achieve the above object, according to the present invention, an inorganic antistatic film is formed on the reading surface side of an optical information recording medium consisting of at least a substrate and a recording layer. An optical information recording medium is provided in which the antistatic film comes into contact with a bearing portion of a spindle that drives the optical information recording medium when the optical information recording medium is mounted on a drive device.

The optical information recording medium of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing the structure of an optical information recording medium according to the present invention, in which a recording layer 2 is formed on one surface of a substrate 1, and the other surface (outer surface) includes one or more transparent conductive films. An antistatic layer 3 is formed. 4 in the figure is a spindle bearing portion on the driving device side.

The substrate 1 is made of polycarbonate, acrylic,
A synthetic resin such as epoxy or PMMA (polymethyl methacrylate) or a 2P substrate is used.

The recording layer 2 may be a medium composed of a reflective film and a protective film such as a CD, a medium composed of a metal recording film such as Te or Bi or a dye recording film and a protective film such as a WORM disk, or a medium composed of a recording film made of a metal such as Te or Bi or a dye recording film and a protective film such as a WORM disk. Like magnetic disks, magnetic films, protective films,
There are media made of reflective films, etc., but the media are not limited to this, and various changes can be made depending on the purpose of use.

The antistatic layer 3 may be composed of an organic protective film mixed with a conductive filler, but in consideration of surface hardness, an inorganic protective film is preferable, especially a transparent film with an antireflection function. It is preferable to use one or more conductive films because it improves the performance (mainly reflectance) of the disk. The antistatic layer 3 is provided so as to come into contact with the bearing portion 4 of the spindle, as shown in the figure, when the optical information recording medium is mounted on the drive device.

[0010] Hereinafter, to further explain, the antistatic layer (
Antireflection layer) 3 is based on the refractive index of the protective layer and substrate 1.
Conventionally, in accordance with the design theory of antireflection layers widely used in optical components, etc., magnesium fluoride, silicon monoxide, silicon dioxide, titanium oxide, and
Films made of transparent insulating materials such as cerium oxide and aluminum oxide, which are used as anti-reflection layers in conventional optical components, and In2O3, ITO, which have a refractive index of around n=2,
It is constructed by combining a transparent conductive film made of an inorganic material such as SnO2 or ZnO. In such an antireflection layer structure, since each film constituting the layer structure is thin, a sufficient antistatic effect can be achieved even if the transparent conductive film is not directly exposed to the outside.

[0011] In addition to these, In2O3, ITO, SnO2, ZnO, although they cannot improve performance such as reflectance.
It is also effective to use a single layer of a transparent conductive film such as the above in order to increase the surface resistance. Further, although the optical information recording medium is usually used as a single plate, there is no problem in using a laminated structure.

Since the antistatic film 3 configured as described above comes into contact with the bearing part (metallic chucking part) 4 of the spindle that rotates the optical information recording medium, it efficiently removes the charges on the outer surface of the optical information recording medium. It can be easily released and prevents static electricity.

Although the present invention has been explained above using several types of optical information recording media as examples, the present invention is not limited thereto, and can be applied to video discs and CDs which are also desired to have an antistatic function. -ROM, CD-V, CD-
It is possible to apply the present invention to various other optical information recording media such as I, CD-XA, and phase change type rewritable optical discs.

[0014]

[Example] Next, an example of the present invention will be described. Example 1 Polycarbonate (diameter 130 mm, thickness 1.2 mm)
PC) A recording layer is provided on one side of the substrate, and the other side consists of three layers: SiO film (λ/4 thickness), In2O3 film (λ/2 thickness), and SiO2 film (λ/4 thickness). An antistatic film was provided to obtain a recording medium according to the present invention. (λ is the laser wavelength.)

Example 2 In Example 1, the antistatic film was made of SiO (λ/4 thickness)/
A recording medium according to the present invention was obtained in the same manner except that ITO (λ/2 thickness)/SiO2 (λ/4 thickness) was used.

Example 3 In Example 1, the antistatic film was made of In2O3 (500 Å
A recording medium according to the present invention was obtained in the same manner except that a single layer film having a thickness of

Comparative Example 1 In Example 1, the antistatic film was an epoxy ultraviolet curing resin (5 μm thick) (organic antistatic film).

Comparative example 2 In Example 1, the antistatic film was not provided.

Measurement of the surface resistance and surface hardness of each recording medium produced as described above, and dust test (installation of the recording medium in the drive device (with the recording medium almost visible)
Then, while rotating, about 10 years' worth of dust (fine particles of SiO2 and Al2O3) was deposited. The results are shown in Table 1.

[0020]

[Table 1]

[0021]

According to the present invention, since the inorganic antistatic film is provided so as to be in contact with the bearing of the spindle, it is possible to efficiently dissipate the electric charge accumulated on the medium, and it is possible to prevent dust from adhering to the medium.

[0022] Inorganic antistatic films containing transparent isoelectric films have antireflection effects in addition to antistatic properties.

Furthermore, since the inorganic antistatic film of the present invention has a high surface hardness, there is less possibility of scratches even if a cartridge case is not used.Also, since the inorganic antistatic film of the present invention has a high surface hardness, even if the medium becomes dirty, it will not be damaged. Dirt can be removed by wiping (usually hardness of about H to 2H is sufficient).

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view for explaining the structure of an optical information recording medium of the present invention and a method of contacting an antistatic film with a spindle bearing part.

[Explanation of symbols]

1 board
2 Recording layer 3 Antistatic layer
4 Spindle bearing part

Claims (2)

[Claims] Claim 1: In an optical information recording medium comprising at least a substrate and a recording layer, an inorganic antistatic film is formed on the reading surface side, and the inorganic antistatic film is formed when the optical information recording medium is installed in a drive device. An optical information recording medium, characterized in that the optical information recording medium comes into contact with a bearing part of a spindle that drives the optical information recording medium. 2. An optical information recording medium characterized in that the inorganic antistatic film is composed of a plurality of layers and includes one or more layers of a transparent conductive film.