JPH10302424A - Optical information recording medium and optical information recording medium holding mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information recording medium holding mechanism capable of performing a clamping even with respect to optical disks of transparent substrates of all kinds of thickness, and an optical information recording medium. SOLUTION: This mechanism is loaded with an optical information recording medium which is provided with a transparent substrate 102 transmitting a laser beam, an information area 103 where the recording or the reproducing of information is performed by being irradiated with the laser beam transmitting the substrate 102 and a center hole 105 positioning a center position and in which an recessed part is provided at an area where is in the outer side than the center hole 105 of at least one side of the substrate 102 and is in the inner side than the information area 103 and metal consisting of magnetic material is fixed in the recessed part. In this case, the mechanism is provided with a positioning means positioning the center position of the information recording medium by engaging the turntable 106 on which the medium is to be loaded with the center hole of the medium and in the means, a recessed part is provided at position corresponding to the metal of the optical information recording medium of the turntable 106 and a magnet is fixed in the recessed part.

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 capable of performing a magnet clamp and an optical information recording medium holding mechanism.

[0002]

2. Description of the Related Art In recent years, the International Organization for Standardization (ISO: Interna
optical discs are standardized by the National Standard Organization, and as a method of clamping to a turntable of a recording / reproducing apparatus, a hub made of a ferromagnetic material is provided on an optical disc, and a magnetic attraction force with a magnet provided on the turntable is used. A magnet clamp system for holding an optical disk is employed.

In the ISO standard, a diameter of 86 mm (3.
5 inch) optical disc is summarized as 1st DP10090 ISO / IECJTC /
SC23 is known. FIG. 2 shows an example of an optical disk with a hub conforming to the ISO standard.

FIG. 2 is a schematic diagram showing a cross-sectional configuration of an example of a conventional optical disk with a hub. In the figure, 201 is a transparent substrate, 202 is an information area, 203 is a center hole, 204 is a hub, 204a is a positioning hole, 204b is a flange, 2
05 indicates a laser beam. The optical disk with a hub is provided with a transparent substrate 201 that transmits a laser beam 205 and an information area 202 in which information is recorded and reproduced by being irradiated with the laser beam 205 that has passed through the transparent substrate 201.

On the optical disk with a hub, a hub 204 formed by shaping a metallic magnetic material into a hat shape by plastic working.
Is a central hole 203 provided in the center of the transparent substrate 201.
And projecting in the incident direction of the laser beam 205. The fixing of the hub 204 is performed by the
b is bonded or welded on the side of the transparent substrate 201 on which the information area 202 is formed.

The clamping of the optical disk with the hub to the turntable is performed by magnetically attracting the hub 204 by a magnet provided on a turntable (not shown). At this time, positioning of the center position of the optical disk with a hub is performed by fitting a positioning hole 204a provided at the center of the bottom of the hub 204 to a spindle shaft of a disk motor for rotating the turntable.

However, the optical disk with a hub shown in FIG. 2 needs a hub 204 formed by forming a ferromagnetic metal into a hat shape by plastic working, so that it is difficult to reduce the cost. there were. In addition, since the hub 204 is provided so as to protrude from the transparent substrate 201, there is a problem that the entire optical disc becomes thick.
Furthermore, since the positioning of the center position of the optical disk is performed by fitting the positioning hole 204a to the spindle of the disk motor, it is necessary to precisely position the hub 204 with respect to the transparent substrate 201 and then bond or weld the hub 204. There has been a problem that the manufacturing apparatus is complicated and large-scale.

An invention relating to an optical disk with a hub for solving the above-mentioned problem is disclosed in Japanese Patent Application Laid-Open No. 5-114169. FIG. 3 shows an example of an optical disk with a hub according to the present invention. FIG. 3 is a schematic diagram showing a cross-sectional configuration of another example of a conventional optical disk with a hub. In the figure, 3
01 is a transparent substrate, 302 is an information area, 303 is a center hole,
304 is a hub, 305 is a turntable, 306 is a spindle shaft, 307 is a guide taper, 308 is a magnet, and 309 is a laser beam.

The optical disk with the hub has a laser beam 30
9 is provided, and an information area 302 in which information is recorded and reproduced by being irradiated with a laser beam 309 transmitted through the transparent substrate 301 is provided. A central hole 303 is provided for performing this. Also, the information area 30 of the transparent substrate 301
A recess is provided on the surface side where the second hole 2 is formed, substantially concentrically with the center hole 303, and a flat hub 304 made of a ferromagnetic metal is attached to the recess by bonding or welding. ing.

When such an optical disk with a hub is clamped to an optical disk holding mechanism of a recording / reproducing apparatus, a state shown in FIG. 3 is obtained. The optical disk holding mechanism includes a spindle shaft 306 rotated by a disk motor (not shown).
, A turntable 305 fixed to the spindle shaft 306, and a magnet 308 fixed to the upper part of the turntable 305.

Here, the turntable 305 is provided with a projection having a guide taper 307 into which the center hole 303 is inserted in order to locate the center position of the optical disk with a hub. An optical disk with a hub is clamped to such an optical disk holding mechanism as follows.

That is, in the optical disk with a hub, the center hole 303 is guided by the guide taper 307 so that the center position is determined and the turntable 305 is positioned.
Placed on When the hub 304 is magnetically attracted by the magnet 308, the optical disk with the hub is clamped on the turntable 305.

As described above, according to the structure of the invention disclosed in Japanese Patent Application Laid-Open No. 5-114169, a hub having a simple shape can be used, and the entire optical disk does not become thicker. When fixing to a transparent substrate,
There is an effect that precise positioning is not required.

On the other hand, attempts have been made to increase the recording density of an optical disc. Usually, one spiral track composed of a sequence of information pits is formed on the optical disc. In order to increase the recording density of a single optical disk, it is known that the distance (pitch) between adjacent tracks is reduced and, at the same time, the information pit length in the tangential direction of the track is reduced. In order to read information pits on such an optical disk, the spot diameter of the laser beam must be reduced.

In order to reduce the spot diameter of a laser beam, the numerical aperture (NA) of an objective lens for converging the light emitted from a semiconductor laser used as a light source must be reduced.
e) may be increased and the oscillation wavelength of the semiconductor laser may be shortened. Furthermore, it is known that it is effective to reduce the thickness of the optical disc substrate in order to perform stable recording and reproducing operations under the condition that a short reproducing light source wavelength and an objective lens having a high NA are used. Have been.

[0016]

In an optical disk with a hub and an optical disk holding mechanism having the configuration shown in FIG.
The height from the disk mounting surface of the turntable 306 to the upper surface of the protrusion having the guide taper 307 needs to match the thickness of the transparent substrate 301 of the optical disk to be mounted. At present, the mainstream thickness of a transparent substrate of a single optical disk is a CD (Compact Disc), an MD (Mini Dis
1.2 mm including c).

On the other hand, with the increase in the density of optical disks and the progress of manufacturing technology, it is expected that optical disks having a thin transparent substrate will become widespread in the future, apart from the above-described optical disks having a thickness of 1.2 mm. The present applicant has also proposed in Japanese Patent Application No. 6-63562, an invention capable of having the same recording capacity as a CD in an optical disk having a transparent substrate having a thickness of 0.6 mm and an outer diameter of 64 mm. .

However, the configuration of the prior art shown in FIG. 3 can cope only with the thickness of one transparent substrate. For example, when the height from the disk mounting surface of the turntable 306 to the upper surface of the protrusion having the guide taper 307 is set to 1.2 mm, an optical disk with a hub having a transparent substrate thickness of 0.6 mm is mounted. If this is attempted, the surface of the optical disk on which the laser beam 309 is incident does not contact the disk mounting surface of the turntable 306,
Since the optical disk is clamped only by the hub 304 and the magnet 308, when the optical disk is rotated, there is a problem that the optical disk immediately comes off.

Conversely, when the height from the disk mounting surface of the turntable 306 to the upper surface of the protrusion having the guide taper 307 is set to 0.6 mm, a hub with a transparent substrate having a thickness of 1.2 mm is provided. When the optical disk is to be placed, there is a problem that the hub 304 and the magnet 308 do not abut, so that they are not clamped.

Therefore, in one reproducing apparatus,
When reproducing optical disks with hubs having different thicknesses, there is a problem that separate clamp mechanisms must be provided.

The present invention has been made to solve the above problems, and has an optical information recording medium holding mechanism capable of clamping an optical disk having any transparent substrate thickness, and an optical information recording medium. It provides a medium.

[0022]

According to a first aspect of the present invention, there is provided a transparent substrate which transmits a laser beam, and wherein the laser beam transmitted through the transparent substrate is irradiated. In the optical information recording medium provided with an information area in which information is recorded or reproduced by the method and a center hole for locating a center position, the information area is outside the center hole on at least one surface of the transparent substrate. A recess is provided in a region inside of the recess, and a metal made of a ferromagnetic material is fixed in the recess.

According to a second aspect of the present invention, there is provided a transparent substrate for transmitting laser light, and an information area on which information is recorded or reproduced by irradiating the laser light transmitted through the transparent substrate. A center hole for positioning a center position, a recess is provided in an area outside the center hole and inside the information area on at least one surface of the transparent substrate, and the recess is made of a ferromagnetic material. In an optical information recording medium holding mechanism in which an optical information recording medium to which a metal is fixed is mounted, a turntable on which the optical information recording medium is mounted, and a center of the optical information recording medium by engaging with the center hole. Positioning means for positioning a position, a concave portion is provided at a position of the turntable facing the metal of the optical information recording medium, and a magnet is fixed to the concave portion. It is intended to.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the optical information recording medium and the optical information recording medium holding mechanism of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram for explaining an optical information recording medium and an optical information recording medium holding mechanism according to an embodiment of the present invention. In the figure, 101 is an optical disk, 102 is a transparent substrate, 103 is an information area, 104 is an annular magnetic body, 105
Is a center hole, 106 is a turntable, 107 is a spindle shaft, 108 is an annular magnet, 109 is a guide taper, and 110 is a laser beam.

The optical disc 101 is irradiated with the transparent substrate 102 transmitting the laser beam 110 and the laser beam 110 transmitted through the transparent substrate 102 to record information,
An information area 103 for reproduction is provided, and a center hole 105 for positioning in the radial direction is provided in the center. Also, the laser light 110 on the transparent substrate 102
In the area inside the information area 103 on the side where
A recess is provided substantially concentrically with the center hole 105, and the recess has an annular magnetic body 104 made of a ferromagnetic metal.
Are attached by bonding or welding.

When the optical disk 101 is clamped on the optical disk holding mechanism of the recording / reproducing apparatus, the state shown in FIG. 1 is obtained.
The optical disk holding mechanism includes a spindle shaft 107 rotated by a disk motor (not shown), a turntable 106 fixed to the spindle shaft 107,
The turntable 106 includes an annular magnet 108 which is inserted into a concave portion formed in the disk mounting portion and is fixed by bonding or welding.

Here, the turntable 106 is provided with a projection having a guide taper 109 which engages with the center hole 105 in order to locate the center position of the optical disk 101. The height from the disk mounting surface of the turntable to the upper surface of the protruding portion can be arbitrarily selected, but the thickness of the transparent substrate having the largest thickness among the clampable optical disks is equal to or greater than the thickness of the thickest optical disk. Is more preferred. The optical disk 101 is clamped to such an optical disk holding mechanism as follows.

The optical disc 101 is placed on the turntable 106 with its center position determined by guiding the center hole 105 of the optical disc 101 to the guide taper 109 at the projecting portion of the turntable 106. And the optical disk 1
01 information area 10 on the side where the laser light 110 is incident
The annular metal magnetic body 104 fixed to an area inside the turntable 3 is magnetically attracted to the annular magnet 108 fixed to the disk mounting portion of the turntable 106, so that the optical disk 101 is turned on the turntable 106. Is clamped to.

In this embodiment, the clamp is performed by the annular magnetic body 104 and the annular magnet 108. However, the shape of the ferromagnetic metal and the magnet is not limited to the annular shape, and the optical disk is mounted on the turntable. When placed, any shape may be used as long as it is in contact with it.

In the present embodiment, the toroidal magnetic body 104 is fixed to the surface of the transparent substrate 102 on the side where the information area 103 is not formed, but the information area 103 of the transparent substrate 102 is formed. You may make it fix to the surface opposite to a surface. In this case, in FIG.
Numeral 10 corresponds to the reproducing apparatus that enters from the upper side of the figure.

Further, as another example, the annular magnetic body 10
4 may be fixed to both the surface of the transparent substrate 102 where the information region 103 is formed and the surface where the information region 103 is not formed. In this case, in FIG.
The present invention can correspond to both a reproducing apparatus in which 10 enters from the lower side of the figure and a reproducing apparatus in which it enters from the upper side of the figure.

As described above, according to this embodiment,
The optical disk 101 is clamped by magnetic attraction on the disk mounting surface side of the turntable 106 with the center hole 105 remaining open without a hub. Therefore, the thickness of the transparent substrate 102 of the optical disk 101 is not limited, and an optical disk of any thickness can be handled.

Further, the optical disk of this embodiment is different from the conventional optical disk with a hub in that it has no center hole or the hub has only a small-diameter center hole. Therefore, it can be easily held on a stacking jig (stocker) similar to a conventional CD. Further, in the optical disk and the optical disk holding mechanism of the present embodiment, it is not necessary to process the ferromagnetic material and the magnet into a complicated shape, and therefore, it can be manufactured at low cost.

According to the present invention, it is possible to provide an optical information recording medium holding mechanism capable of clamping an optical information recording medium having any transparent substrate thickness.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining an optical information recording medium and an optical information recording medium holding mechanism according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a cross-sectional configuration of an example of a conventional optical disk with a hub.

FIG. 3 is a schematic diagram showing a cross-sectional configuration of another example of a conventional optical disk with a hub.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Optical disk 102 Transparent substrate 103 Information area 104 Ring magnetic body 105 Center hole 106 Turntable 107 Spindle shaft 108 Ring magnet 109 Guide taper 110 Laser beam 201 Transparent substrate 202 Information area 203 Center hole 204 Hub 204a Positioning hole 204b Flange 205 Laser light 301 Transparent substrate 302 Information area 303 Center hole 304 Hub 305 Turntable 306 Spindle shaft 307 Guide taper 308 Magnet 309 Laser light

Claims (2)

[Claims] 1. A transparent substrate through which a laser beam is transmitted, an information area in which information is recorded or reproduced by irradiating the laser beam through the transparent substrate, and a center hole for positioning a center position. An optical information recording medium comprising: a concave portion provided in a region outside the center hole and inside the information region on at least one surface of the transparent substrate,
An optical information recording medium, wherein a metal made of a ferromagnetic material is fixed in the recess. 2. A transparent substrate through which a laser beam is transmitted, an information area in which information is recorded or reproduced by irradiating the laser beam through the transparent substrate, and a center hole for positioning a center position. Comprising a recess in a region outside the center hole and inside the information region on at least one surface of the transparent substrate,
An optical information recording medium holding mechanism in which an optical information recording medium in which a metal made of a ferromagnetic material is fixed in the recess is mounted, wherein the turntable on which the optical information recording medium is mounted is engaged with the center hole; Positioning means for locating the center position of the optical information recording medium according to the following. A concave portion is provided in the turntable at a position facing the metal of the optical information recording medium, and a magnet is fixed to the concave portion. An optical information recording medium holding mechanism, characterized in that: