JPH06176526A - Optical disk cartridge - Google Patents

Abstract

PURPOSE:To suppress the adhesion of dust to an optical disk by preventing the electrification of the case of the optical disk cartridge. CONSTITUTION:A member (conductive plastic material, etc.) 3 which is not electrified to the extent of order of 10<9>OMEGA surface resistivity or below is applied or stuck to at least the inside surface of the case 2 made of nonconductive plastic. The case 2 itself is otherwise formed of the conductive plastic member. As a result, the inside surface of the case 2 is hardly electrified and, therefore, the optical disk 1 in proximity to the case 2 is hardly electrified as well and the generation of Coulomb force between the dust and the optical disk does not arise even if air contg. the electrified dust flows near to the optical disk 1. The adhesion of the dust on the optical disk 1 is thus suppressed. The effect is higher if the surface of the optical disk 1 is subjected to an antistatic treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk cartridge, and more particularly to an optical disk cartridge which does not cause dust adhesion due to static electricity.

[0002]

2. Description of the Related Art FIG. 2 is an exploded perspective view of a general optical disk cartridge used in a conventional optical disk device. As shown in FIG. 2, an optical disk cartridge having a structure in which an optical disk 1 is rotatably covered by a plastic case 2 having substantially the same shape as the upper and lower sides is known.

Since an optical head (not shown) performs recording and reproducing in the vicinity of the optical disk 1, in order to avoid interference between the optical head and the optical disk cartridge case 2, the range in which the optical head moves is in this case 2. There is a rectangular or oblong opening 4 (hereinafter referred to as a “head opening”) that is slightly larger. In addition, the case 2 has an optical disk 1
An opening 5 opened approximately in the center of the case 2 for rotating
(Hereinafter referred to as “spindle opening”).
The optical disc cartridge is provided with a shutter 6 and a slide opening / closing mechanism (not shown) for covering the two types of openings 4 and 5 for the purpose of dust protection and scratch protection of the optical disc 1 when the cartridge is not mounted in the apparatus. Has been.

With such a structure, when actual recording or reproduction of information is performed in the optical disc apparatus, wind is caused by the rotation of the optical disc, and there is always wind flow inside the optical disc cartridge.

On the other hand, since the optical disk device has a feature that the optical disk recording medium can be exchanged, it is impossible to completely spatially separate the outside of the device from the inside of the device, and the hermetically sealed property like a known magnetic disk device is not possible. Is difficult to secure. Therefore, the structure is such that the wind outside the apparatus, that is, the air in the general atmosphere, is carried inside the optical disk cartridge.

By the way, generally, the wind contains fine dust, and most of the dust is positively or negatively charged. Therefore, these dusts are attracted and adhere to the optical disk having the opposite pole or the inner surface of the cartridge case.

Here, the structure of the optical disk is shown in a sectional view of FIG. The optical disc has a recording film layer 10 and a recording film layer 10.
And a layer 11 of a substrate of plastic material such as glass or polycarbonate for protection of the. The recording film layer 10 is bonded to the substrate 11 via a photo-curing resin layer (not shown) having preformat recording. Although not shown, in the actual structure, two pieces shown in FIG. 3 are provided, the recording film layer 10 is on the inside, the substrate 11 is on the outside, and both sides of the metal hub (not shown) of the central member are shown. It has a structure in which it is vertically symmetrically attached. In the optical disk device, recording is performed by changing the recording film layer 10 with laser light, and reproducing is performed by detecting the change with laser light as well. As described above, when dust adheres to the optical disk (on the surface of the substrate 11), the adhering material blocks the laser light, making it difficult for the prescribed amount of light to reach the recording film layer 10, which hinders recording or reproduction. There is a problem.

Therefore, it is necessary to take measures to prevent dust from adhering to the rotating optical disk.
As described in Japanese Patent No. 03436 (Reference 1),
In particular, from the viewpoint of mass productivity, an optical disk has been proposed in which a conductive transparent film is formed on a substrate made of a plastic material such as polycarbonate, which has recently been used in place of glass to reduce dust adhesion due to static electricity. There is.

[0009] Further, in order to prevent dust from entering the optical disc cartridge and adhering the dust to the optical disc, a shutter that covers the opening is an ISO standard / IE.
There is an example in C / DIS9171-1 (reference 2). Further, the one in which the spindle opening is closed by a dustproof seal member during operation is disclosed in, for example, Japanese Patent Laid-Open No. 64-46255 (Reference 3).
Has been proposed by.

Further, as described in Japanese Patent Laid-Open No. 3-108173 (reference 4), there has been proposed a device which reduces dust by forming a conductive coating on the surface of the cartridge facing the magneto-optical disk. However, since the surface resistance value is as low as 10 ² Ω, the selection of materials is limited, which is not practical. Further, although the conductive coating is applied only to the cartridge side, the reduction of dust adhesion is not always sufficient.

[0011]

When air blows through the current optical disc cartridge made of a non-conductive plastic material as shown in FIG. 2, static electricity is generated on the inner surface of the cartridge case due to the friction of the wind.

[0012] On the other hand, according to the one in which the surface of the optical disk is treated with a conductive film as shown in the above-mentioned document 1, electrostatic charge on the surface of the optical disk is prevented, and when the optical disk alone exists, the disk itself is present. The adhesion of dust to the can be reduced.

However, since the optical disk is stored in the cartridge case and stored and used, an electric field is generated when the inner surface of the optical disk cartridge case is charged, and the optical disk rotating oppositely is also charged in the cartridge case. It is charged to the opposite pole from the inner surface. For this reason, even in the case of an optical disk having a conductive film processed, if wind occurs due to the rotation of the disk, it is not possible to prevent dust from adhering to the generated electric field.

Further, with the method of closing the opening of the optical disk cartridge with the shutter or the dustproof sealing member as shown in the above-mentioned documents 2 and 3, it is difficult to completely close the opening during storage and operation, and it is difficult to completely close the opening. It is not possible to adequately prevent entry into

Further, it is not practical to apply a coating of a conductive material having a low surface resistance of 10 ² Ω to the cartridge as in Reference 4, because the selection of the material is limited.

Under such circumstances, there is a problem that the optical disc must be frequently cleaned when the optical disc is actually used. There is also a problem that the optical disc is damaged during cleaning.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and prevent the charging of both the surface of the optical disk and the inner surface of the optical disk cartridge, without losing the characteristic that the medium of the optical disk can be replaced. An object of the present invention is to provide an optical disk cartridge in which dust adhesion due to static electricity on the disk surface is drastically reduced and cleaning of the disk surface is not required.

[0018]

To achieve the above object, the present invention provides an optical disc cartridge having a disc-shaped recording medium and a case for covering the disc-shaped recording medium, and at least a recording / reproducing area of the disc-shaped recording medium. Is subjected to an antistatic treatment, and the inner surface of the case facing the recording / reproducing area is subjected to an antistatic treatment such that the surface resistivity is on the order of 10 ⁹ Ω or less, or the inner surface of the case is surface-treated. It is characterized by being formed of a conductive member having a resistivity of 10 ⁹ Ω or less.

When the substrate of the disk-shaped recording medium is made of a material such as glass that is not easily charged, the antistatic treatment (conductive member) does not necessarily have to be applied to the disk-shaped recording medium, and the disk-shaped recording medium is not necessarily charged. It may be applied only to at least the inner surface of the case facing the recording / reproducing area.

[0020]

The operation based on the above configuration will be described.

Generally, the rotation of the disk inside the optical disk cartridge causes a flow of air inside and outside through the spindle opening and the head opening of the optical disk cartridge. The wind flow contains suspended substances such as dust charged with various electric potentials. When the cartridge case and the optical disk are charged, dust is attracted by the Coulomb force and adheres to them. According to the present invention, by performing antistatic treatment on the inner surface of the case of the optical disc cartridge facing at least the recording / reproducing area of the disc-shaped recording medium, generation of static electricity or charging is suppressed, and an optical disc of a glass substrate that is originally difficult to be charged or There is almost no electric field between the plastic disk that has been subjected to antistatic treatment such as a conductive film and the inner surface of the cartridge case that has been subjected to antistatic treatment such that the surface resistivity is on the order of 10 ⁹ Ω or less. Almost no dust is generated, and dust hardly adheres to the surface of the optical disc or the cartridge case.

In the present invention, in particular, it has been found that a material having a relatively high surface resistivity of the order of 10 ⁹ Ω or less, which has not been neglected in the past, is effective as an antistatic material and is extremely effective in removing dust. Therefore, an inexpensive plastic material can be used for antistatic, and the range of choice of materials can be expanded.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention. Figure 1
Shows a cross section of the optical disc cartridge, in which the optical disc 1 subjected to the conductive film treatment is rotatably accommodated inside the optical disc cartridge. In order to prevent the inner surface of the cartridge case 2 made of non-conductive plastic such as polycarbonate from being charged, a conductive coating 3 is applied to the inner surface of the case 2.

FIG. 4 shows the actual surface resistance value (surface resistivity).
The relation between the surface resistance value (surface resistivity) and the relative adhesion amount when the device is operated using a disk coated with 10 ¹² Ω is shown. The same applies to a disk coated with a surface resistivity of 10 ¹¹ Ω.

Here, for the measurement of the surface resistivity, for example,
"Plastic Handbook", pp. 397-398, published by Plastic Age Co., Ltd.
The value per unit surface area (1 cm 2) was calculated using the method shown on page 7.4.2 (Reference 5).
That is, a circular center electrode and a ring-shaped electrode concentric therewith are arranged on the surface to be measured, the diameter of the center electrode is d, the inner diameter of the ring-shaped electrode is D (> d), and the resistance value between both electrodes is Rs.
And the surface resistivity ρs = Rs × π (D + d) /
It is determined by (D-d). Moreover, the relative amount of adhesion is 2.53 × 10 ⁷ pieces / ft ^{3 in the} cartridge case.
It was measured after being put in the dust tank of the above-mentioned dust environment for 4 hours.

The surface resistivity of the cartridge is such that at least the inner surface of the cartridge is 10 ⁸ , 10 ⁹ , 10 ¹⁰ , and 10.
Antistatic agents, materials, etc. were used so that they would be ¹¹ , 10, ¹² and 10 ¹⁴ Ω. In fact, 10 ⁸ Ω or less to Sumitomo Co., Ltd. "electromagnetic guard spray", Colcoat to 10 ⁹ Ω (Ltd.) "Colcoat N-114X", 10 ¹⁰ - 1
0 ¹¹ - 10 ¹² Antistatic agent entrained plastic is the Omega, 10
Polycarbonate was used for ¹⁴ Ω. Relative coverage is
The amount of adhesion to the disk surface and the percentage of the amount of adhesion of each surface resistance to the disk surface when using a cartridge having a surface resistivity of 10 ¹⁴ Ω are shown. As is apparent from FIG. 4, if the surface resistivity is on the order of 10 ⁹ Ω, there is a great effect (about 1/5) on the adhesion of dust, and if it is less than that, the same effect can be obtained. It was confirmed that the same effect was obtained for the lens. It was also confirmed that the same effect was obtained when glass was used for the disc. by this,
The device life can be extended five times.

As described above, even if an antistatic agent, a surface active agent, a surface active agent-containing coating agent, or a conductive coating agent is applied so that the surface resistivity is not higher than the order of 10 ⁹ Ω, a remarkable effect can be obtained. Of course, a thin metal film may be formed by plating. Also, metal foil, metal plate,
A conductive rubber sheet or plastic sheet may be attached. Furthermore, the surface resistivity of the cartridge case 2 is set to 10 ⁹
It may be formed of a conductive plastic having an Ω order or less. The use of conductive plastic also has the advantage that no secondary processing steps are required.

Next, the range subjected to the antistatic treatment is shown in FIG.
Shown in. The range 8 subjected to this antistatic treatment substantially corresponds to the portion of the inner surface of the cartridge case 2 facing the recording and readable portion 7 of the optical disc 1, but the range subjected to the antistatic treatment is the recording area. Also, a certain effect can be obtained if it is slightly larger than the readable portion. Further, when the outer surface of the cartridge case 2 facing the inner surface of the cartridge case 2 is subjected to the antistatic treatment, a greater effect can be obtained. It is considered that this is because the outer surface is not charged, and thus the electric field that goes inward is not generated by the charging. Of course, the antistatic treatment area may be made of conductive plastic, or a thin metal plate may be attached. Further, the antistatic coating may be applied to the entire inner surface of the cartridge case or the entire cartridge, the entire cartridge case may be made of conductive plastic, or a thin metal plate may be attached.

A case of a cartridge case according to another embodiment is shown in FIGS. FIG. 6 shows a type in which the head opening and the spindle opening are commonly used as one opening 9. However, the range in which the antistatic treatment is applied or the conductive plastic is applied is the range 8 as in the previous example.

Further, in the case of the type having the cartridge case 2 in which the optical disc cartridge is divided as shown in FIG. 7 when it is mounted in the optical disc device, recording and reading of the optical disc 1 in the state where it is mounted in the optical disc device can be performed. The antistatic treatment is applied to the inner surface of the case 2 facing the portion 7, or conductive plastic is applied. In both cases shown in FIG. 6 and FIG. 7, as in the case of FIG. 5, the antistatic treatment may be applied to the entire inner surface, or conductive plastic may be applied, or it may be applied to all cases 2. Good.

In the above embodiment, the case where the optical disk substrate is made of polycarbonate and the antistatic treatment is applied to both the surface of the optical disc and the inner surface of the case of the carridge is explained. Even if the antistatic protection is omitted, there is some effect. In particular, when the optical disk substrate is made of a material such as glass that is hard to be charged, it is possible to considerably reduce the charge by simply performing an antistatic treatment on the inner surface of the cartridge case. Furthermore, when both the surface of the optical disc and the inner surface of the case are subjected to the antistatic treatment, the electrification can be eliminated by an order of magnitude as compared with the case where the surface of the conventional optical disc is subjected to the electrification treatment.

Further, according to the above-described embodiment, the antistatic property is not provided even if an electric grounding means such as grounding the inner surface of the cartridge case, which has been subjected to the antistatic treatment with a conductive coating agent, by the optical disk device during operation is not provided. The generation of static electricity can be prevented in advance only by applying treatment. In addition,
If such electrical grounding means is provided as needed (for example, grounding is performed via the shutter 6 made of metal and the optical disk device), it is more effective.

In the present invention, basically, the surface resistivity may be on the order of 10 ⁹ Ω or less in order to obtain the antistatic effect, but in practice, the surface resistivity of a typical plastic is 10 ⁵ Ω. It is about 10 ¹⁸ Ω, and since the conductive plastic particles are mixed in order to obtain a surface resistivity of 10 ⁵ Ω or less, the original characteristics of the plastic are largely impaired depending on the kind of the plastic. Surface resistivity of 10 ⁵ Ω to 10 ⁹ Ω, which is electrically conductive and has antistatic effect
It is practical to use a plastic material of the order.

[0035]

As described above in detail, according to the present invention, at least the recording / reproducing area is provided in the optical disk of the glass substrate which is originally difficult to be charged, or the optical disk cartridge having the optical disk having at least the recording / reproducing area subjected to the antistatic treatment. The inner surface of the cartridge case opposite to the surface of the cartridge is subjected to antistatic treatment so that the surface resistivity is on the order of 10 ⁹ Ω or less, thereby preventing both the surface of the optical disk and the inner surface of the cartridge from being electrically charged. It is possible to obtain an effect that it is possible to suppress the adhesion of dust to the optical disk or the case to an extremely small amount during the operation of the device where dust is likely to adhere.

In particular, in the present invention, it was found that a material having a relatively high surface resistivity of the order of 10 ⁹ Ω or less is extremely effective in preventing static electricity as compared with a material having a surface resistivity higher than 10 ⁹ Ω. The range is widened, and it is possible to obtain the effect that the dust can be sufficiently removed by using various inexpensive antistatic materials made of plastic.

[Brief description of drawings]

FIG. 1 is a partial side sectional view of an optical disk cartridge showing a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a conventional optical disk cartridge.

FIG. 3 is a partial side sectional view of a general optical disc.

FIG. 4 is a diagram showing the relationship between the surface resistivity and the amount of attached dust in the example of the present invention.

FIG. 5 is a partial perspective view of an optical disk cartridge showing a second embodiment of the present invention.

FIG. 6 is a partial perspective view of an optical disk cartridge showing a third embodiment of the present invention.

FIG. 7 is a partial perspective view of an optical disk cartridge showing a fourth embodiment of the present invention.

[Explanation of symbols]

1 Optical Disk 2 Optical Disk Cartridge Case 3 Conductive Coating Layer 4 Head Opening 5 Spindle Opening 6 Shutter 7 Recordable and Readable Range of Optical Disk 1 8 Range of Antistatic Treatment or Application of Conductive Plastic 9 Opening 10 Recording Film Layer 11 Glass layer

Front page continuation (72) Inventor Tokuya Kaneda 2880 Kozu, Odawara-shi, Kanagawa Hitachi Storage Systems Division (72) Inventor Hitoshi Takizawa 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa In the system (72) Inventor Makoto Miura 1-88, Torora, Ibaraki City, Osaka Prefecture Hitachi Hitachi Ltd.

Claims (4)

[Claims] 1. An optical disc cartridge having a disc-shaped recording medium and a case for covering the disc-shaped recording medium, wherein at least a recording / reproducing region of the disc-shaped recording medium is subjected to an antistatic treatment, and at least the recording / reproducing region. The inner surface of the opposing case has a surface resistivity of 10
An optical disk cartridge characterized by being subjected to an antistatic treatment so that it is less than the order of ⁹ Ω. 2. An optical disc cartridge having a disc-shaped recording medium and a case for covering the disc-shaped recording medium, wherein at least a recording / reproducing region of the disc-shaped recording medium is subjected to an antistatic treatment and is opposed to the recording / reproducing region. An optical disk cartridge, wherein the inner surface of the case is formed of a conductive member having a surface resistivity of the order of 10 ⁹ Ω or less. 3. An optical disc cartridge having a disc-shaped recording medium and a case for covering the disc-shaped recording medium, wherein a substrate of the disc-shaped recording medium is glass and at least faces a recording / reproducing area of the disc-shaped recording medium. An optical disk cartridge characterized in that the inner surface of the case is subjected to an antistatic treatment such that the surface resistivity is on the order of 10 ⁹ Ω or less. 4. An optical disc cartridge having a disc-shaped recording medium and a case for covering the disc-shaped recording medium, wherein a substrate of the disc-shaped recording medium is glass and faces at least a recording / reproducing area of the disc-shaped recording medium. An optical disk cartridge, wherein the inner surface of the case is formed of a conductive member having a surface resistivity of the order of 10 ⁹ Ω or less.