JPH05128776A - Optical disk - Google Patents

Abstract

PURPOSE:To provide interchangeability with driving devices of different kinds by centering the optical disk by a central hole provided on the optical disk or the centering hole provided in the chucking hub. CONSTITUTION:The outer peripheral edge 2a of the chucking hub 2 provided in order to chuck the disk to the position corresponding to the central hole 1a of the optical disk 1 is fixed by an adhesive 3 to the optical disk 1. The centering hole 4 of a small diameter is projectingly provided at the center of the chucking hub 2 and is engaged, in the case of high performance, with the centering pin 9 provided on the disk table 5 of the driving device, by which the optical disk is positioned with high accuracy. The optical disk is centered by engaging the inner peripheral edge of the central hole 1a and the tapered part provided on the disk table in the case of low performance. The centering even to the driving devices of a low rotating speed and a high rotating speed is enabled and the interchangeability is assured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc for recording / reproducing information signals by irradiating a laser beam, and more particularly to an optical disc provided with a chucking hub.

[0002]

2. Description of the Related Art Conventionally, as optical discs for recording / reproducing information signals by irradiating laser light, magneto-optical discs, various write-once optical discs, rewritable optical discs,
Various media such as digital audio discs (so-called compact discs) and optical video discs (so-called laser discs) have been put into practical use.

By the way, in a drive device for writing / reading information signals to / from such an optical disc, further miniaturization and thinning are required.

Therefore, in order to meet such a demand, in the conventional art, a disk-shaped chucking hub made of a metal material is attached to an optical disk, and this is magnetically attracted by a magnet built in the disk table, so that the optical disk is made to be a disk table. It is designed to be chucked.

According to this structure, the complicated chucking mechanism conventionally provided on the lid of the drive device can be eliminated, so that the drive device can be significantly thinned and the number of parts is greatly reduced. be able to.

[0006]

By the way, in the optical disk having the chucking hub mounted thereon as described above, it is magnetically attracted by the magnet built in the disk table and is inserted into the center hole provided at the substantially central portion of the disk. The tapered portion of the disc table is fitted so that the center of the disc table and the center of rotation of the disc match (hereinafter,
This is called centering. ) It is designed to be punished. Then, in this state, the disc table rotates, and the optical disc is irradiated with the laser beam from the optical pickup device to perform recording / reproduction.

However, in the above optical disc,
Although the tape is chucked on the disk table by the magnet with the taper portion of the disk table fitted in the center hole of the disk, recording / reproduction gradually deteriorates as the rotational speed of the disk increases. This is because the centering accuracy is not sufficient. Therefore, there is no problem in low-performance low-model drive devices that record / reproduce at a relatively low rotation speed, but good recording / reproduction is possible in high-performance high-model drive devices that record / reproduce at high rotation speed. Cannot play back.

Therefore, the present invention has been proposed in view of the above technical problems, and provides a compatible and highly reliable optical disk capable of excellent recording / reproducing for drive devices of different models. The purpose is to provide.

[0009]

In order to achieve the above-mentioned object, the present invention provides an optical disc in which a chucking hub is attached to the optical disc, and a central hole or a chucking hub provided at a substantially central portion of the optical disc. It is characterized in that it is centered by a hole formed in the.

[0010]

In the optical disk according to the present invention, for a drive device having a low rotation speed, the taper portion of the disk table is fitted into the center hole provided at the substantially central portion of the disk for centering, and the rotation speed is high. The drive device is centered by engaging a centering pin provided on the disk table with a hole formed in the chucking hub. In other words, the optical disk according to the present invention can be used for both models with low rotation speed and high rotation speed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. As shown in FIG. 1, the optical disc 1 of the present embodiment is, for example, a magneto-optical disc, various write-once optical discs, rewritable optical discs,
It has a recording layer on at least one surface, such as a digital audio disc and an optical video disc. In these optical discs 1, information signals are written in or read from the recording layer or both writing and reading are performed by optical means or magneto-optical means.

For example, in a magneto-optical disk, a recording layer including a perpendicularly magnetized film having a magneto-optical effect is formed on a disk substrate made of a transparent resin molding or glass, and the recording layer is further covered thereon. And a protective film is laminated. The recording layer is a layer capable of optically recording / reproducing information signals, for example, a dielectric base film made of Si ₃ N ₄ or the like, a perpendicular magnetization film made of TbFeCo alloy or the like, S
An upper dielectric film made of i ₃ N ₄ or the like and a metal reflection film made of Al or the like are sequentially laminated by a vacuum thin film forming technique such as sputtering.

On the other hand, an optical disk such as a CD is protected from a recording layer on an ultraviolet-curing resin layer having grooves and pits formed on a disk substrate made of a resin molding made of polycarbonate or the like formed by injection molding. The film layers are sequentially laminated. Such a disk substrate is usually formed by the so-called 2P method because it is excellent in mass productivity and economical efficiency.

Since these optical discs 1 are generally formed by an injection molding method in which a resin is poured into a mold, the optical disc 1 has a circular center hole 1a at the substantially central portion thereof. The center hole 1a includes a center of the recording track and the center hole 1a.
Are formed so as to substantially coincide with the centers of the above, but usually, these centers may be slightly shifted depending on the temperature at the time of molding.

As shown in FIG. 2, a chucking hub 2 for chucking the optical disk 1 is provided on the disk table of the drive device at a position corresponding to the center hole 1a of the optical disk 1. There is. The chucking hub 2 is formed by pressing a metal plate into a disk-shaped dish having a size sufficient to cover the center hole 1a, and is fixed to one surface of the optical disc 1 with an adhesive 3 or the like. Has been done. That is, in the chucking hub 2, the center of a later-described centering hole formed in the chucking hub 2 is aligned with the center of the recording track, and the outer peripheral edge portion 2a provided so as to cover the center hole 1a and the optical disk 1. The adhesive 3 is applied to the contact portion of and is fixed to the optical disc 1.

In particular, in the optical disc 1 of this embodiment, a small diameter centering hole 4 is formed substantially in the center of the chucking hub 2 for highly accurate centering. The centering hole 4 serves to position the optical disk 1 on the disk table with high accuracy by engaging with a centering pin provided on the disk table of a high-performance drive device that requires high rotation speed and high-speed seek. Is. In other words, the purpose is to enable good recording / reproduction for a highly accurate drive device that requires a high rotation speed.

In the optical disc 1 having such a structure, for example, for a low-performance low-performance drive device for recording / reproducing at low rotation speed and low speed seek, as shown in FIG. Centering is performed by a center hole 1a provided at a substantially central portion of 1. That is, the optical disk 1 is magnetically attracted to the disk table 5 by the magnet 6 built in the disk table 5 of the drive device.
The inner peripheral edge portion of the center hole 1a engages with the tapered portion 7 provided on the tip end side of the center for centering. in this case,
As described above, the center of the recording track and the center hole 1a
The center may deviate depending on the temperature at the time of injection molding, but such a deviation causes no problem in recording and reproduction in the low rotation speed region.

Incidentally, as shown in FIG. 4, good recording / reproducing can be similarly performed on the optical disc 1 having a step at the portion where the chucking hub 2 is attached. Further, as shown in FIG. 3, if the disk table 5 is provided with a receiving surface 8 for supporting the disk surface of the optical disk 1, the optical disk 1 is provided.
The flatness of the
Better recording / playback can be performed.

On the other hand, as shown in FIG. 5, a centering hole 4 formed in the chucking hub 2 is used for centering a high-performance high-performance drive unit for recording / reproducing at high rotation speed and high-speed seek. Is done. That is, the optical disk 1 is magnetically attracted to the disk table 5 by the magnet 6 built in the disk table 5 of the drive device, and the cylindrical centering pin 9 formed so as to project at a substantially central portion of the disk table 5 is described above. It engages with the centering hole 4 and is centered. In this way, since the centering pin 9 having the substantially same diameter is engaged with the centering hole 4, the center of the disc table 5 and the rotation center of the optical disc 1 coincide with each other with high accuracy. Therefore, even if the optical disc 1 is rotated at a high rotation speed, good recording and reproduction can be performed.

Even in this high-performance high-performance drive device, if the disk table 5 is provided with a receiving surface 8 for supporting the disk surface of the optical disk 1, as shown in FIG. Can be reduced, and better recording and reproduction can be performed.

The specific embodiments to which the present invention is applied have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, as shown in FIG. 7, a central portion of the chucking hub 2 is projected toward the disc table 5 so as to face the inside of the central hole 1a, and both end walls of the disc-shaped metal plate 10 are erected. Is provided
Even if the chucking hub 2 in which the centering hole 4 is provided at the substantially central portion of the metal plate 10 is used, the same effect can be obtained.

The present invention can also be applied to disks having the same format and the same shape. Particularly, in this case, optical disks having different performances can be manufactured using almost the same production equipment.

[0023]

As is apparent from the above description, according to the optical disk of the present invention, it is substantially the center of the optical disk for a low-performance low-performance drive device for recording / reproducing at a low rotation speed. For a high-performance high-performance drive device that performs centering in a central hole provided in the section and performs recording / reproduction at a high rotational speed, centering is performed in the centering hole formed in the chucking hub. Therefore, recording / reproducing can be favorably performed on drive devices of different models, and compatibility can be ensured.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an optical disc to which the present invention is applied.

FIG. 2 is an enlarged sectional view of an essential part showing a state in which an optical disc to which the present invention is applied is mounted in a low performance drive device.

FIG. 3 is an enlarged cross-sectional view of an essential part showing a state where the optical disc to which the present invention is applied is mounted in a low-performance drive device having a receiving surface.

FIG. 4 is an enlarged cross-sectional view of an essential part showing a state in which an optical disc having a step at a portion to which a chucking hub is attached is mounted in a low performance drive device.

FIG. 5 is an enlarged sectional view of an essential part showing a state in which an optical disk to which the present invention is applied is mounted in a high performance drive device.

FIG. 6 is an enlarged cross-sectional view of an essential part showing a state where the optical disc to which the present invention is applied is mounted in a high-performance drive device having a receiving surface.

FIG. 7 is an enlarged cross-sectional view of an essential part showing a state in which an optical disk having a chucking hub having a different shape is mounted in a high-performance drive device.

[Explanation of symbols]

 1 ... Optical disc 1a ... Center hole 4 ... Centering hole 5 ... Disc table 6 ... Magnet 9 ... Centering pin

Claims (1)

[Claims] 1. An optical disc in which a chucking hub is attached to the optical disc, wherein the optical disc is centered by a center hole provided at a substantially central portion of the optical disc or a hole formed in the chucking hub.