JPS63293733A - Optical disk - Google Patents

Abstract

PURPOSE:To form an optical disk which is usable for optical disk devices of both a mechanical clamping system and magnet clamping system by providing a toric magnetic metallic plate into a space constituted of a 1st substrate and the 2nd substrate as well as the inside circumferential part of an inside circumferential spacer. CONSTITUTION:The 1st substrate 21 and 2nd substrate 22 are formed of a nonmetallic material such as polycarbonate and are the disks which have recording media for optically storing information and have a hole for positioning when mounted to the optical disk at the center. The outside circumferential spacer 23 and inside circumferential spacer 24 are toric members having the same thickness and are held in place between the 1st substrate 21 and the 2nd substrate 22. The air layer of a specified thickness is formed by adhering and fixing these substrates and spacers. The magnetic metallic plate 25 is the toric magnetic metallic member which is disposed into the space between the 1st substrate 21 and the 2nd substrate 22 as well as the inside circumferential part of the inside circumferential spacer 24 by having a degree of freedom. The use of this optical disk to both the optical disk device of the magnet clamping system and the optical disk device of the mechanical clamping system is thereby enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disc-shaped optical disc used for optically recording or reproducing information.

[Conventional technology]

Conventional optical discs used to optically record or reproduce information consist of two substrates (a first substrate and a second substrate) containing a recording medium and an outer peripheral spacer to maintain a constant distance between them. and an inner peripheral spacer.

Among such optical disks, the structure is different between a mechanical clamp method and a magnetic clamp method for fixing the optical disk when it is mounted on an optical disk device. That is, as shown in FIG. 2, an optical disk device using a mechanical clamp method has a first substrate
In order to create an air layer between the substrate 2 and the second substrate 2, an annular outer circumferential spacer 3 and an annular inner circumferential spacer 4 of a predetermined thickness made of a non-metallic material such as polycarbonate are sandwiched between them. , which has a structure in which both substrates are bonded and fixed, and is used in a magnetic clamp type optical disk device, as shown in FIG.
A circular ring-shaped flange (magnetic metal flange) 16 made of magnetic metal is fixed to the outside of the center of the magnetic metal.

[Problem that the invention seeks to solve]

Conventional optical discs as described above have a substrate made of a non-metallic material such as polycarbonate, so there is a drawback that optical discs designed for mechanical clamping cannot be used as is in optical disc devices using magnetic clamping. On the other hand, optical disks using the magnetic clamp method bond and fix a magnetic metal flange to the outside of the substrate, so the thickness of the clamp part is thicker than that of optical disks using the mechanical clamp method. The disadvantage is that it cannot be used in optical disk devices. Furthermore, with magnetic clamp type optical disks, there is a large difference in the coefficient of thermal expansion between the substrate and the magnetic metal flange, so changes in ambient temperature can cause distortion in the substrate and change its refractive index, making it difficult to record or reproduce information. The disadvantage is that it may not be possible.

The purpose of the present invention is to solve the above-mentioned drawbacks of conventional optical discs, to be usable in both mechanical clamp type and magnetic clamp type optical disc devices, and to improve the reliability of recording and reproducing information. Our goal is to provide excellent optical discs to customers.

[Means for solving problems]

The optical disc of the present invention includes a first substrate and a second substrate for recording information, and an outer circumferential spacer that adheres and fixes the first substrate and the second substrate while maintaining a constant distance between them. and an inner circumferential spacer, the optical disk having an annular magnetic metal plate in a space formed by the first substrate, the second substrate, and an inner circumferential portion of the inner circumferential spacer.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the present invention.

In FIG. 1, the first substrate 21 and the second substrate 22 are
It is a disk made of a non-metallic material such as polycarbonate and has a recording medium for optically storing information, and has a hole in the center for positioning when it is installed in an optical disk device. This is the first substrate 1 and 11 in FIGS. 2 and 3.
and second substrates 2 and 12.

The outer circumferential spacer 23 and the inner circumferential spacer 24 are annular members having the same thickness, and are sandwiched between the first substrate 21 and the second substrate 22, and are fixed with adhesive to maintain a constant thickness. forms an air layer. The magnetic metal plate 25 is the first substrate 2
It is a magnetic metallic annular member disposed with a degree of freedom in the space between the first and second substrates 22 and the inner circumferential portion of the inner circumferential spacer 24 . Therefore, even when the ambient temperature changes, the volume change is absorbed by the free space, and the first substrate 21 and the second substrate 22 are not deformed.

When the optical disk constructed as described above is used in a mechanical clamp type optical disk device, it can be used under the same conditions as the conventional example shown in FIG. 2 without a magnetic metal plate. Further, when used in a magnetic clamp type optical disk device, the magnetic metal plate 25 can function as the magnetic metal flange 16 shown in FIG. 3.

〔Effect of the invention〕

As explained above, the present invention does not fix a magnetic metal plate on the surface of an optical disk, but incorporates it into two substrates, so that it can be applied to optical disk devices using a magnetic clamp method as well as optical disks using a mechanical clamp method. It has the advantage that it can also be used for disk devices. In addition, since the magnetic metal plate is not fixed to the substrate, even when the ambient temperature changes, the substrate is deformed due to the difference in thermal expansion between the substrate and the magnetic metal, and the resulting change in refractive index makes it difficult to record and reproduce information. This has the effect of not degrading performance. Therefore, there is also the effect that standardization of optical discs or optical disc devices becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing an embodiment of the present invention.
FIG. 3 is a sectional view showing an example of a conventional optical disc using a mechanical clamp method. FIG. 3 is a sectional view showing an example of an optical disc using a conventional magnetic clamp method. 1, 11, 21...first board, 2, 12, 22...
Second board, 3/13/23...Outer spacer, 4/1
4, 24... Inner spacer, 16... Magnetic metal flange, 25... Magnetic metal plate.ゝ＼Two, 2 Spear I Figure jil; 2 Figure 3III

Claims (1)

[Claims] A first substrate and a second substrate for recording information, and an outer circumferential spacer and an inner circumferential spacer for adhering and fixing the first substrate and the second substrate with a certain distance between them. What is claimed is: 1. An optical disk comprising: an annular magnetic metal plate in a space formed by the first substrate, the second substrate, and an inner circumferential portion of the inner circumferential spacer.