JPH06259814A - Mask for exposure and optical recording medium - Google Patents

Abstract

PURPOSE:To precisely fit a hub to an optical recording medium independently of the track pitch at a low cost by forming a positioning pattern for fitting a hub on the optical recording medium with a mask for exposure having a positioning pattern for fitting a hub. CONSTITUTION:A positioning pattern 46 concentric with a guide layer pattern 45 is formed on an optical recording medium 52 with a mask for exposure having a positioning pattern for fitting a hub. A hub is fixed so that a positioning pattern 26 concentric with a central hole 28 coincides with the positioning pattern 46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the recording of information by light,
The present invention relates to an exposure mask and an optical recording medium for forming a predetermined pattern on an optical recording medium for reproduction or erasing.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 10, an optical recording medium 100 is provided with a hub 102 for holding the optical recording medium 100 on a drive shaft of an optical disk drive.
The hub 102 includes a suction plate 105 having a positioning hole 104 formed in the center and a support member 106. A magnet is installed in the clamp portion of the drive shaft of the optical disk drive, and the optical recording medium 100 is clamped and held by the drive shaft by the attraction force between the attraction plate 105 made of a magnetic material and the magnet. Further, the positioning hole 104 is mounted so that the eccentricity is extremely small so that stable servo is possible even at high speed rotation.

Therefore, the hub 102 is mounted on the optical recording medium 100 by the method shown in FIG. That is, the optical recording medium 100 is held by the vacuum suction device 201 and rotated by the driving device 203 such as a motor. Next, the optical head 20
5, the optical recording medium 100 is irradiated with laser light to perform focusing and tracking servo. At this time, the position of the optical recording medium 100 is adjusted by the moving device 208 so that the tracking error signal for driving the objective lens 206 in the radial direction is minimized, that is, the eccentricity is minimized. In this state, an ultraviolet curable resin is dropped from the nozzle 210, and then the hub 102 is brought into close contact with the optical recording medium 100 by the hub mounting material 212, and then ultraviolet rays are irradiated to cure and bond.

[0004]

However, when the hub 102 is mounted on the optical recording medium 100 in this way, it is necessary to adjust the position of the optical recording medium 100 while applying the tracking servo with the optical head 205. For this reason, the track pitch is narrow and has been conventionally used.
The optical head for 6 μm has a problem that the hub cannot be mounted when tracking is not applied. Further, when the optical head corresponding to each track pitch is used, there is a problem that the price of the optical recording medium increases because the optical head is expensive.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide an exposure mask which enables inexpensive and accurate hub mounting without depending on the track pitch. And to provide an optical recording medium.

[0006]

In order to achieve this object, the present invention according to claim 1 provides an exposure mask having a predetermined pattern used for forming tracking or the like on an optical recording medium. A hub mounting positioning pattern is provided together with a predetermined pattern. The present invention according to claim 2 is an optical recording medium in which information is reproduced, recorded, or erased by light, and a hub mounting positioning pattern is provided in the vicinity of the stop hole. To do.

[0007]

The exposure mask of the present invention is provided with a predetermined pattern used for tracking and the like and a hub mounting positioning pattern. The predetermined pattern for tracking is formed along a spiral shape or a concentric shape to define a track. A hub mounting positioning pattern is formed on this track so as to reduce the eccentricity.

Further, the optical recording medium has a hub mounting positioning pattern formed in the vicinity of the stop hole. Therefore, when the hub is mounted, the positioning can be performed without using the optical head with the positioning pattern provided on the hub, and the hub can be mounted with high accuracy.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In an exposure mask 10 to which the present invention is preferably applied, as shown in FIG. 1, a tracking pattern for forming a guide film for generating a push-pull signal used for tracking on a transparent substrate 12. 14 and four hub mounting positioning patterns 16 are provided. The hub mounting positioning pattern 16 is formed so as to be concentric with the rotation center when the tracking pattern 4 is formed, for example.

Here, the transparent substrate 12 is made of glass, fused silica or the like, and the tracking pattern 14 and the hub mounting positioning pattern 16 are made of a chromium (Cr) thin film or the like.

As shown in FIG. 2, the hub 20 has a suction plate 22.
And a supporting member 24, and a positioning pattern 26 is formed on the supporting member 24. The positioning pattern 2
6 is a central hole 28 provided in the center of the suction plate 22, for example.
It is formed to be concentric with.

The exposure mask 10 is manufactured by the method shown in FIG. That is, as shown in FIG.
A chromium thin film 30 is formed on the second layer 2 by a sputtering method or the like. Further, a photoresist 31 is spin coated thereon. Next, as shown in FIG. 3B, the substrate 12 is rotated by the spindle motor 34 and irradiated with the argon laser 35 to expose a predetermined tracking pattern. After the exposure of the tracking pattern, the hub mounting position is irradiated with the argon laser 35 to expose the hub mounting positioning pattern as shown in (c). As described above, since the exposure of each pattern is performed without removing the substrate 12 from the spindle motor, the center of rotation when the tracking pattern is formed and the center of the hub mounting positioning pattern can be aligned. After the development, the chromium thin film 30 in the portion where the photoresist 31 is removed is etched, and the remaining photoresist 31 is removed, whereby the exposure mask 10 is manufactured as shown in FIG.

Using such an exposure mask 10, an optical recording medium is manufactured by the method shown in FIG. That is,
As shown in FIG. 3A, a metal thin film 42 such as tantalum is formed on a substrate 41 such as glass by a well-known thin film forming means such as a sputtering method, and a photoresist 4 is formed thereon.
3 is spin coated. Further, an exposure mask 12 is brought into close contact therewith, and ultraviolet rays are irradiated to perform exposure. When the development is performed, the same pattern as the exposure mask 12 is formed by the photoresist 43 as shown in FIG. Photoresist 43
When the metal thin film 42 not covered with is removed by plasma etching or wet etching using an etching solution, a guide film 45 having the same shape as the tracking pattern is formed as shown in FIG. Also,
At the same time, the hub mounting positioning pattern 46 is also formed.
An interference layer 48, a recording layer 49, and a protective layer 50 are laminated thereon by a well-known thin film forming means such as a sputtering method as shown in FIG. Further, an optical recording medium 52 is manufactured by forming a cover layer 51 made of an ultraviolet curable resin or the like on the cover layer 51.

Here, for the substrate 41, a resin or the like, preferably a transparent material having a high solvent resistance such as amorphous polyolefin or glass or the like is used. In addition, the guide film 45
For example, a metal such as aluminum, tantalum, gold, silver, copper, or titanium, or a compound such as titanium nitride is used. The interference layer 48 and the protective layer 50 include, for example, SiO ₂ , SiAlON,
Transparent oxides such as SiN and AlN, nitrides, etc. are used. For the recording layer 49, a magneto-optical recording material made of, for example, a rare earth transition metal alloy such as TbFeCo or GdTbFe is used.

The hub 20 is inserted into the center of the optical recording medium 52 as shown in FIG. At this time, an ultraviolet curable resin is previously applied between the support material 24 and the cover layer 51 of the optical recording medium 52. Here, the cover layer 51
When observed with an observation device such as a microscope from the side, the optical recording medium 5
Since the positioning patterns 46 and 26 formed on the hub 2 and the hub 20 look like FIG. 5, for example, the positioning is performed based on this. After the alignment is completed, the hub 20 is irradiated with the ultraviolet rays in that state to make the hub 20 the optical recording medium 5.
Stick to 2. At the time of alignment, as shown in Fig. 5,
It is not necessary to observe the entire positioning patterns 26 and 46 at the same time, and only the vicinity where the positioning pattern 46 is formed may be observed. Furthermore, the positioning pattern 46
You may observe simultaneously the several vicinity in which is formed with several observation devices.

The positioning pattern 26 is provided so as to be concentric with the central hole 28 provided in the suction plate 22. Further, the centers of the positioning patterns 26 and 46 are fixed so that they coincide with each other as described above. further,
It is formed so as to be concentric with the positioning pattern 46 and the tracking pattern of the guide film 45 used for tracking. As a result, the center hole 28 of the hub 20 and the tracking pattern of the guide film 45 are concentric, so that the eccentricity can be made extremely small.

Although one embodiment of the present invention has been described in detail with reference to FIGS. 1 to 5, the present invention can be implemented in other modes.

For example, positioning patterns 16 and 26
The pattern shape, its size, the pattern width, the position, and the number are not particularly limited.

For example, as shown in FIG. 6, both positioning patterns 16 and 26 may have concentric circles.
At this time, if the positioning pattern 46 formed on the optical recording medium based on the positioning pattern 16 matches as shown in FIG. 9A, the positioning is performed with sufficient accuracy, and as shown in FIG. By measuring the moire pattern, it is possible to detect the positional deviation from the state of (a).

The positioning pattern 26 may be formed in a convex shape or a concave shape on the support member 24 of the hub 20. It may also be printed on the support material 24.

The hub 20 is not limited to being fixed to the cover layer 51 side. For example, it may be fixed to the substrate 41 side.

The structure of the optical recording medium 10 is not limited to the structure shown in FIG. 4D as long as the positioning pattern is formed. For example, as shown in FIG. 7, the dielectric layer 60 may be provided on the substrate 41 and the guide film 45 may be provided thereon.
Further, the reflective layer 61 may be provided on the protective layer 50. By providing the dielectric layer 60, the apparent Kerr effect of the magneto-optical recording layer 49 is increased and the reproduction characteristics are improved. Furthermore, by thinning the recording layer 49 and providing the reflective layer 61, the Faraday effect of the magneto-optical recording layer 49 can be utilized, and the reproduction characteristic is improved.

Further, as shown in FIG. 8, the positioning pattern 4
The opaque recording layer 4 is formed on the upper part of the portion where the 6 is formed.
9 and the reflective layer 61 may not be formed. This facilitates the observation of the positioning pattern 46. Further, similar effects can be obtained without forming not only the opaque recording layer 49 but also the interference layer 48 and / or the protective layer 50 on the portion where the positioning pattern 46 is formed.

The interference layer 48 is not always necessary and may not be provided. In this case, the difference in reflectance between the guide layer and the recording layer may be detected, and tracking may be performed by, for example, the 3-beam method.

The recording layer 49 is not only made of a rare earth transition metal alloy other than TbFeCo, a multi-layered film of PtCo or PdCo, an oxide magnetic material such as rare earth iron garnet, and a magneto-optical material combining these, as well as Te, Bi and the like. A perforated type, a phase change type material such as GeSbTe or TeO _x , an organic material such as a pigment may be used.

Further, the guide film 45, the interference layer 48, the protective layer 5
The material such as 0 is also not particularly limited. Further, they may be composed of a multilayer film using a plurality of materials.

The shape of the exposure mask 10 and the tracking pattern formed on it are not particularly limited. For example, as shown in FIG. 9, a part 70 of the pattern
Are formed continuously along a concentric circle or a spiral with a predetermined width to form a recording area pattern 72. Also,
It may have a portion 74 formed in a pit shape so as to generate a sector mark, a format signal or the like, and this portion constitutes an index pattern 76. Moreover, you may have the mirror pattern part in which the pattern is not formed.

[0029]

As is clear from the above description, according to the exposure mask of the present invention, the predetermined pattern used for tracking and the like and the hub mounting positioning pattern are provided. The hub mounting positioning pattern can be formed so as to reduce the eccentricity with respect to the track. Further, according to the optical recording medium of the present invention,
The hub can be mounted so that the positioning pattern formed on the support material of the hub and the positioning pattern for hub mounting formed on the optical recording medium match, and high precision is achieved without using an expensive optical head. You can install the hub with.

[Brief description of drawings]

FIG. 1 is a plan view of an exposure mask that is an embodiment of the present invention.

2A is a plan view of the hub, and FIG. 2B is a cross-sectional view of the hub.

FIG. 3A to FIG. 3D are cross-sectional views of essential parts showing a method for manufacturing an exposure mask that is an embodiment of the present invention.

4A to 4E are cross-sectional views of a main part showing a method for manufacturing an optical recording medium according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of positioning by a positioning pattern.

FIG. 6 is an explanatory diagram of positioning according to another embodiment of the alignment pattern.

FIG. 7 is a cross-sectional view of essential parts showing another embodiment of the optical recording medium of the present invention.

FIG. 8 is a cross-sectional view of essential parts showing another embodiment of the optical recording medium of the present invention.

FIG. 9 is a plan view of a main portion showing a pattern of another example of the exposure mask.

FIG. 10 is a cross-sectional view of essential parts showing a conventional optical recording medium.

FIG. 11 is an explanatory diagram showing a method of mounting a hub on a conventional optical recording medium.

[Explanation of symbols]

 10 exposure mask 14 tracking pattern 16 hub mounting positioning pattern 52 optical recording medium 46 hub mounting positioning pattern

Claims (2)

[Claims] 1. An exposure mask in which a predetermined pattern used for forming tracking or the like is formed on an optical recording medium, wherein a hub mounting positioning pattern is provided together with the predetermined pattern. 2. An optical recording medium in which information is reproduced, recorded, or erased by light, wherein a hub mounting positioning pattern is provided in the vicinity of the central hole.