JP2001076453A - Optical disk cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an erroneous tracking operation without needing any complex opening/closing mechanisms for opening/closing a window by detachably providing a window not to be opened/closed, made of a material transmitting a reproducing light so as to be replaced. SOLUTION: This optical disk cartridge 10 is provided with an upper case and a lower case 14 formed by injection-molding thermoplastic synthetic resins, not transmitting lights, and a disk-shaped optical disk 16 housed inside. In the lower case 14 of the optical disk cartridge 10, a rectangular opening part 14D is formed along the radial direction of the optical disk 16, and a window 18 transmitting a recording/reproducing light is fitted in the opening part 14D. This window 18 is preferably be colored so as to shut off a light other than the recording/reproducing light for preventing the deterioration of the pigment- containing recording layer of the optical disk 16. Thus, the damaging of the optical disk 16 is prevented, and a protective layer having low resistance to damaging is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cartridge for an optical disk.

[0002]

2. Description of the Related Art Conventionally, reading of information recorded on an optical disk has been performed by irradiating the disk with laser light from the substrate side and focusing on a recording layer or a pit. For this reason,
The spot diameter on the substrate surface is, for example, about 1 mm in the case of a CD, and even if there is a small flaw of about 0.1 mm on the substrate surface, the area of the flaw on the spot diameter is small. Did not come out.

However, recently, in order to increase the resolution, a technique has been proposed in which information is read out by irradiating the recording layer directly or via a protective layer with a laser beam without passing through a substrate. In this case, if the exposed recording layer or the thin protective layer is damaged, there is a possibility that the information cannot be reproduced because the area of the damage with respect to the spot diameter is large. Error correction is performed in preparation for such a case, but if the scratch is along the tracking direction (circumferential direction), the tracking signal will cause abnormal noise in the tracking signal for a long time, The possibility of occurrence of a tracking malfunction increases.

[0004]

To avoid such a problem, an optical disk loaded in a cartridge having a light-shielding window that can be opened and closed has been proposed, but a complicated mechanism is required to open and close the window. It is.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide an optical disk cartridge capable of preventing a tracking malfunction without requiring a complicated mechanism.

[0006]

That is, the present invention provides an optical disk cartridge having a non-openable / closable window formed of a material that transmits reproduction light.

According to the present invention, since this window transmits laser light, there is no need to open and close the window, and no mechanism for opening and closing is required.

However, since the scratches on the window are always involved in information reproduction, it is preferable that the window be removable so that it can be replaced. Further, it is preferable that the window is colored so as to block light other than recording and reproduction light.

Further, in order to prevent the window from being damaged, it is preferable that the window is recessed from the periphery of the window or that a projection is provided in the periphery of the window.

[0010] The entire cartridge may be formed of a material that transmits reproduction light.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

As shown in FIG. 1, an optical disk cartridge 10 is formed by injection molding of a thermoplastic synthetic resin such as a polycarbonate resin, an ABS resin, and a polystyrene resin, and includes an upper case 12 that does not transmit light and a lower case 14. ing. As shown in FIG. 2, these cases are respectively composed of substantially square plate-like portions 12A, 14A and peripheral portions 12B, 14B extending vertically from the peripheral edge of the upper portion of the plate, and the peripheral portions 12B, 14B are formed. It is arranged to face each other. In addition, circular holes 12C and 14C are formed at substantially the center of these cases.

The optical disk cartridge 10 accommodates a disk-shaped optical disk 16. The optical disk 16 may be a CD (compact disk) or a DVD (digital video disk), and includes a transparent substrate having a pregroove formed on at least one surface. A hole 16A smaller than the holes 12C and 14C of the optical disk cartridge 10 is formed substantially at the center of the transparent substrate. Around the hole 16A, a protrusion 16B protrudes from both surfaces along the circumferential direction. The protrusion 16 </ b> B prevents both sides of the substrate of the optical disk 16 from contacting the optical disk cartridge 10. A liner may be provided between the optical disk 16 and the optical disk cartridge 10.

A dye-containing recording layer is provided on a transparent substrate. Dyes used in the dye-containing recording layer include cyanine dyes, phthalocyanine dyes, azo dyes, oxonol dyes, and the like. These dyes may be used alone or in combination of two or more. The dye-containing recording layer may contain an anti-fading agent, a binder, and the like, in addition to the dye.

To increase the resolution, it is preferable to irradiate the recording layer directly with laser light, but it is also possible to irradiate laser light from the substrate side. In the case where the recording layer is directly irradiated with laser light, it is preferable to provide a reflection layer between the recording layer and the substrate and in the case where the laser light is irradiated from the substrate side, on the recording layer. Aluminum, gold,
Silver, platinum and copper are preferred, and gold and silver are particularly preferred.

A protective layer can be provided on the recording layer at the recording layer side incidence and on the reflection layer at the substrate side incidence.

An intermediate layer can be provided between the substrate, the recording layer, the reflective layer and the protective layer. When an intermediate layer is provided between the reflective layer and the recording layer, the reflectance and the recording characteristics are improved. In the case where an intermediate layer is provided between the recording layer and the protective layer, the recording layer is prevented from being eroded during the application of the protective layer.

The optical disk may be a single-plate type or a laminated type. In the case of a single-plate type, a dye-containing recording layer may be provided on one of the substrates, and a recording layer or pits may be provided on the other. The recording layer and pits are 2
When there are more than two layers, both-side reading or single-side reading may be used.

A rectangular opening 14D is formed in the lower case 14 of the optical disk cartridge 10 along the radial direction, and a window 18 through which recording and reproducing light is transmitted is fitted in the opening 14D. The window is made of a synthetic resin such as polycarbonate, amorphous polyolefin, PMMA (polymethyl methacrylate), epoxy, PET (polyethylene terephthalate), polystyrene, ABS (acrylonitrile-butadiene-styrene), or glass. Among these, polycarbonate, PMMA and amorphous polyolefin are preferred, and polycarbonate is particularly preferred.

This window is preferably colored so as to block light other than recording and reproduction light in order to prevent deterioration of the dye-containing recording layer. As a coloring method, a coloring material may be kneaded into the window 18 or a coating of the coloring material may be provided on the surface of the window 18. When providing a coating, it is preferable to provide it inside the window 18.

As shown in FIG. 3, the window 18 is recessed from the lower case 14. In order to prevent damage, the lower case 14 may be provided with a projection 20 surrounding the window as shown in FIG. Window 18 and lower case 1
The step of the projection 4 or the protrusion 20 is preferably at least 0.05 mm, more preferably at least 0.1 mm, even more preferably at least 0.15 mm. When forming the protrusion 20, the protrusion may be discontinuous or continuous, but is preferably continuous.

According to the present invention, since the optical disk 16 is protected by the cartridge 10, the optical disk 16
Is prevented from being damaged. For this reason, it becomes possible to use a protective layer having low scratch resistance. If the window 18 is made thin, the resolution can be increased. Further, since the window 18 is recessed from the lower case 14, scratches are prevented. Further, since the window 18 does not open and close, dust does not easily enter the inside of the cartridge, thereby reducing the adhesion of dust to the optical disk 16. Therefore, the protective layer of the optical disk 16 can be made extremely thin or omitted. it can.

The window 18 is preferably detachable so that it can be replaced when it is damaged. Further, a hard film may be provided on the surface of the window to prevent damage. When a part of the window is damaged, it is preferable to shift the relative position of the pickup to avoid an error due to the damage.

The window 18 is not limited to a flat plate but may function as a lens. This provides two objective lenses,
It is possible to increase the resolution.

Although the entire lower case or the entire cartridge may be used as a window, a part of the window can reduce the cost of coloring. In the case of double-sided reading, a window is also provided in the upper case 12.

The optical disk cartridge may be box-shaped or cylindrical.

[0027]

Embodiments of the present invention will be described below, but the present invention is not limited to the embodiments. (Example 1) Using a transparent polycarbonate pellet (Panlite AD5503) manufactured by Teijin Limited, a spiral pre-groove (pre-groove width 500 nm,
A substrate having a pregroove depth of 175 nm (thickness: 0.6 mm, inner diameter: 15 mm, outer diameter: 120 mm) was formed by injection molding.

Next, 2.65 of the following cyanine dye (A1)
g to 2,2,3,3-tetrafluoropropanol 10
The resultant was dissolved in 0 ml to prepare a coating solution for forming a recording layer. This coating solution is applied to the surface of the obtained substrate on which the pre-groove is formed by spin coating while changing the rotation speed from 300 to 2000 rpm, and dried to dry the dye recording layer (pre-groove inner thickness: about 200 nm). Was formed.

[0029]

Embedded image Next, Ag was sputtered on the dye recording layer to a thickness of 150 n.
m reflective layers were formed. Further, a UV curable resin (trade name: SD-316, manufactured by Dainippon Ink and Chemicals, Inc.) was applied on the reflective layer by spin coating while changing the rotation speed from 300 to 4000 rpm. After the application, the coating was irradiated with ultraviolet light from a high-pressure mercury lamp and cured to form a protective layer having a thickness of 8 μm.

On the other hand, a counter substrate (thickness: 0.6 mm, outer diameter: 120 mm, inner diameter: 15 mm) was prepared from the above-mentioned polycarbonate.

The two substrates are superimposed on each other so that the protective layer is on the inside, and are bonded to each other using an ultraviolet-curable acrylate adhesive (XNR5522) manufactured by Ciba Geigy Co., Ltd. so that the adhesive layer thickness becomes 40 μm. Was.

Through the above steps, a CD-R type optical disk was obtained.

This optical disk was loaded into a polystyrene cartridge (the material of the window was polycarbonate, and the thickness of the window was 0.6
mm, the window was colored so as to cut off light having a wavelength of 700 nm or less, and the other portions were light-impermeable. (Comparative Example 1) An optical disk was obtained in the same manner as in Example 1 except that the thickness of the substrate was set to 1.2 mm, and the substrate was not bonded to the counter substrate and was not put in a cartridge.

The cartridge of Example 1 and the optical disk of Comparative Example 1 were scratched along the circumferential direction with a length of 1 mm using a cutter knife.

When the data was reproduced in an unrecorded state by applying tracking with a DDU1000 (manufactured by Pulstec), tracking was not lost in Example 1, but it was deviated in Comparative Example 1.

[0036]

According to the present invention, it is possible to provide an optical disk cartridge which can prevent a tracking malfunction without requiring a complicated mechanism.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical disk cartridge of the present invention.

FIG. 2 is a plan view of the optical disk cartridge of FIG.

FIG. 3 is a sectional view of a peripheral portion of a window.

4A and 4B show a peripheral portion of a window, where FIG. 4A is a sectional view and FIG.
Is a plan view.

[Explanation of symbols]

 10 Optical disk cartridge 18 Window

Claims (6)

[Claims] 1. An optical disk cartridge having a non-openable window formed of a material that transmits reproduction light. 2. The optical disk cartridge according to claim 1, wherein said window is detachable. 3. The optical disk cartridge according to claim 1, wherein the window is colored. 4. The optical disk cartridge according to claim 1, wherein the window is recessed from a peripheral portion of the window. 5. The optical disk cartridge according to claim 1, wherein a projection is provided around the window. 6. An optical disk cartridge formed of a material that transmits reproduction light.