JPS63255845A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To obviate degradation in a defect rate occurring in adhesion of foreign matter and to extend the service life of a optical information medium by providing oil films to the light beam incident surfaces of substrates. CONSTITUTION:The oil films are provided to the light beam incident surfaces 7 of the substrates 1, 1a. An oily material for forming the oil films 7 is preferably transparent and non-volatile and has excellent chemical stability and is more particularly preferably a lubricating oil which is frequently used as an oleo-agent for the magnetic recording medium. The substrate surface is thereby smoothed and the direct contact of foreign matter with the substrate is prevented. The foreign matter is, therefore, easily removed merely by lightly wiping the substrate surface with a liner or the like provided in a cartridge case or driving device.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical information recording medium, and more particularly.

The present invention relates to surface cleaning means applied to a light beam incident surface of a substrate.

[Conventional technology]

Generally, in optical information recording media, a light beam is irradiated from the outside of the substrate to the interface between the signal pattern surface of the substrate and a recording film or a reflective film, and changes in the intensity of the reflected light are read as information. . Therefore, if foreign matter such as dust or oily mist adheres to the surface of the substrate, the amount of light beam transmitted through the substrate is reduced or blocked, directly causing recording and reproduction errors. Therefore, in this type of optical information recording medium, it is particularly required that the surface of the substrate Φ be kept clean at all times.

Conventional optical information recording media do not have any means to prevent foreign matter from adhering to them, and the surface of the substrate must be wiped with a flexible cloth or the like before being mounted on a drive device. For example, a liner made of non-woven fabric is provided in the cartridge case that stores the optical information recording medium and in the drive device that drives the optical information recording medium to record and reproduce information, so that the surface of the substrate is protected while the optical information recording medium is being driven. It has been proposed to automatically dispel 1;

[Problem that the invention seeks to solve]

By the way, since the substrate is required to have high light transmittance, it is usually made of ceramics such as glass, polycarbonate (PC), polymethyl methacrylate (
PMMA), polymethylpentene, and epoxy resin.

However, since all of these substrate materials are dielectrics and tend to generate static electricity, they tend to attract foreign matter such as dust and oily mist in the air to the surface of the substrate. When an oily substance and dust are mixed, the viscosity becomes high, and the mixture sticks to the substrate and becomes difficult to wipe away.

In particular, if it is left for a long time, it deteriorates and becomes a sticky substance with even higher viscosity, which firmly adheres to the substrate and becomes difficult to remove even by wiping it with a flexible cloth, liner, or the like. As a result, the optical properties of the substrate surface become non-uniform.
Problems arise in that the CN ratio of the reproduced signal deteriorates, and in the worst case, it becomes impossible to record and reproduce information, and the defect rate falls below the allowable limit.

The present invention has been made to solve the problems of the prior art described above, and its purpose is to provide an optical information recording medium that allows easy removal of foreign matter adhering to the surface of a substrate and has excellent recording and reproducing characteristics. It is in.

[Means for solving problems]

The present invention is characterized in that an oil film is provided on the light beam incident surface of the substrate in order to achieve the purpose of tilting.

[Effect]

Providing an oil film on the light beam incident surface of the substrate makes the substrate surface smooth and prevents foreign matter from coming into direct contact with the substrate. Therefore, the foreign matter can be easily removed by simply wiping the surface of the substrate lightly with a liner or the like provided in the cartridge case or the drive device, and the substrate will not be damaged.

〔Example〕

First, an outline of the optical information recording medium according to the present invention will be explained based on FIG.

FIG. 1 is a cross-sectional view of an optical information recording medium with a so-called air sandwich structure, where 1+la represents two substrates constituting this optical information recording medium, and 2 and 2a are formed on each of the substrates 1 and 1a. 3 is a recording film formed on the signal pattern 2.2a, 4 is the substrate 1, 1a.
an inner circumference spacer 5 interposed on the inner circumference of the substrate 1;
An outer circumferential spacer is interposed on the outer circumference of the substrate 1a, 6 is an air gap, and 7 is an oil film attached to the outer surface of the substrates 1 and 1a.

Said substrate 1. la is made of ceramics such as transparent glass, or transparent resin materials such as PC, PMMA, polymethylpentene, and epoxy resin, and the intermediate area excluding the innermost and outermost peripheries on one side Signal patterns 2, 2a corresponding to predetermined tracking signals, address signals, etc. are formed on the signal pattern 2, 2a, and a record 113 made of a desired heat mode recording material is formed on the signal pattern 2.2a.

The two substrates 1 and 1a produced as described above are pasted together with the recording film 3 inside through the inner circumferential spacer 4 and outer circumferential spacer 5, and between the recording 1!13.3 A desired air gap 6 is provided to obtain a double-sided recording type optical information recording disk.

oil! ! As the oil-based substance for forming 117, any known oil substance can be used, but it is preferable that it is transparent, non-volatile, and has excellent chemical stability. Lubricating oils that are often used as oil-impregnating agents for media (for example, Monteclas's product name R)
FOMBLINJ.

Product name of Shuposi Co., Ltd. rKRYTOXJ or rVYD
AXJ) is particularly preferred.

The oil g17 can be formed uniformly over the entire surface of the substrates 1, 1a, or can be formed only on the area corresponding to the recording [113 (signal pattern 2゜2a) of the surface of the substrate 1゜la. It can also be formed into The film thickness can be formed to any desired thickness depending on the type of oily substance that forms the oil film as long as the transparency of the substrates 1 and 1a is not impaired, but in the case of the above-mentioned substances, approximately 5 people ~ 100
It is preferable to form it to a thickness of 0.0 mm.

The oil [1! As a method for forming the $7 layer, known liquid coating methods such as a roll coating method, a spin cord method, a spray method, and a dipping method can be used.

In the optical information recording medium of the above embodiment, transparent and non-volatile oil 1117 is formed on the surfaces of the substrates 1 and 1a, so that the surfaces of the substrates are smooth and foreign matter such as dust is prevented from coming into direct contact with the substrates. be able to. Therefore, even if foreign matter is attracted to the surface of the substrate 1.18 during storage or handling, the foreign matter can be easily removed by simply wiping the surface of the substrate with a liner provided inside the cartridge case or drive device. be able to.

Hereinafter, specific examples of the present invention will be listed and effects of the present invention will be described.

1st Example Two 5.25-inch PC boards, each having a hard coat treatment on the light beam incident surface and a T e S e based low melting point alloy film formed on the signal pattern surface, were bonded together. An optical information recording disk having an air sand inch structure was prepared and dipped in a Freon liquid in which FOMBLIN oil manufactured by Monteclas was dissolved to form an oil film of FOMBLIN oil on the surface of the substrate.

Second Example An optical information recording disk having an air sandwich structure was fabricated by bonding together two 12-inch PC substrates each having a recording film of a T e S e based low melting point alloy formed on the signal pattern surface. As in the case of the first embodiment, Monte, hlu
The substrate was dipped into a Freon liquid in which FOMBL IN oil manufactured by OS was dissolved to form an oil film of FOMBLIN oil on the surface of the substrate. Note that the light beam incident surface of the substrate of this embodiment is not hard coated.

Comparative Example An air sandwich consisting of two 5.25-inch PC substrates, each of which has a hard coat treatment applied to the light beam incident surface and a recording film of T e S e based low melting point alloy formed on the signal pattern surface. An optical information recording disk with this structure was used as a comparative example. Of course, on the surface of the board.

No oil film is formed.

Evaluation of each optical information recording disk produced as described above was performed according to the procedure shown in FIG. 2. First, Figure 2 (a
) As shown in Figure 2(b), a clean optical information recording disk is loaded into a defect rate measuring device and the initial defect rate is determined. Leave it alone.

Foreign matter in the air naturally adheres to the substrate surface.

Next, as shown in FIG. 2(e), foreign matter adhering to the substrate surface as described above is cleaned.

Finally, as shown in FIG. 2(d), the cleaned optical information recording disk is mounted on a defect rate measuring device, and the defect rate after cleaning is determined.

The table below shows the defect rates of the optical information recording disks of each example measured as described above, except for Test Examples 1, 2.4.
In this method, a cleaning method was adopted in which an operator wiped the surface of each substrate with a woven chemical fiber cloth. Furthermore, in Test Example 3, as shown in FIG. A cleaning method was employed in which the tip of the nylon brush 13 was brought into contact and the optical information recording film disk was rotated about 20 times.

As is clear from the table above, in the conventional optical information recording disk (comparative example) in which no oil film is formed on the substrate surface, once foreign matter has adhered to the substrate surface in the air, the operator can Even if cleaning is performed to the extent of wiping with a woven cloth, the defect rate will worsen by about one order of magnitude. On the other hand, in the optical information recording disk of the present invention in which an oil film is formed on the substrate surface, even if foreign matter adheres to the substrate surface in the air and the defect rate worsens by nearly two orders of magnitude, one worker cannot use chemical fibers. By simply wiping the surface with a woven cloth, the defect rate returns to almost the initial defect rate. For this reason, optical information recording disks with an oil film formed on the substrate surface in advance prevent foreign matter from firmly adhering to the substrate surface, and prevent the defect rate from worsening over time due to contamination of the substrate surface. It was found to be effective.

In the above embodiment, two disk substrates 1. l
Although an optical information recording disk with a so-called air sandwich structure, in which the optical information recording disks A and A are bonded together via spacers 4 and 5, has been described, the gist of the present invention is not limited to this.
The present invention can be applied to all known types of optical information recording disks, such as optical information recording disks with a so-called single-plate structure and optical information recording disks with a so-called closely bonded structure.

Further, in the above embodiments, the case where the present invention is applied to a disk-shaped optical information recording medium has been described, but the gist of the present invention is not limited to this. For example, the present invention is not limited to this. The present invention can be applied to any other optical information recording medium, such as an optical information recording medium, in exactly the same manner.

In addition, since the oil film formed on the substrate surface only needs to be extremely thin, once a predetermined amount of oily substance is applied to the substrate surface to form an oil film, the oil film will remain semi-permanently on the substrate surface. It is estimated to be. However, if it is necessary to always form an oil film with a constant thickness, 1. For example, by arranging a pad impregnated with a suitable oily substance in the cartridge case, the desired oily substance can be applied to the substrate surface. It is also possible to replenish it as appropriate.

[Clearing effect]

As explained above, since the optical information recording medium of the present invention has an oil film formed on the substrate at least at a position corresponding to the recording film, foreign matter such as dust or oily mist may get on the surface of the substrate during storage or handling. Even so, it can be easily cleaned.

Therefore, the defect rate does not deteriorate due to adhesion of foreign matter, and the service life of the optical information medium can be extended.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an optical information recording disk showing an embodiment of the present invention, FIG. 2 is a flowchart showing a procedure for measuring a defect rate, and FIG. 3 is a sectional view showing an example of a substrate cleaning means. 1, la: substrate s 2 H2a: signal pattern. 3: Recording film, 4: Inner circumference spacer, 5; Outer circumference spacer, 6
: Air gap, 7: Oil film, 11: Optical head, 12:
Defect rate measuring device, 13: Nylon brush 1 Figure 1.1a: Substrate 2.2a: Signal power 3: Self-contained, I'l Ying. 4: Inner periphery spacer 5; Outer spacer 6; Air carrier...l 7: Mount membrane

Claims (3)

[Claims] (1) An optical information recording medium having at least one substrate on which a recording film or a reflective film is provided on a signal pattern surface, characterized in that an oil film is provided on the light beam incident surface of the substrate. . (2) The optical information recording medium according to claim 1, wherein the oil film is made of transparent and nonvolatile liquid lubricating oil. (3) The optical information recording medium according to claim 1, wherein the oil film has a thickness of 5 Å to 1000 Å.