JPH0341641A - Optical disk - Google Patents

Abstract

PURPOSE:To improve and stabilize performance and to miniaturize the optical disk device by assuring a space larger than the quantity of a dimensional change at the time of an ambient temp. change in the space constituted of a 1st substrate, a 2nd substrate and an inner peripheral spacer and building a magnet therein. CONSTITUTION:An outer peripheral spacer 3 and the inner peripheral spacer 4 are adhered and fixed to the 1st substrate 1 and the 2nd substrate 2. The magnet 5 is built into the space constituted of the 1st substrate 1, the 2nd substrate 2 and the inner peripheral spacer 4 in which the space larger than the quantity of the dimensional change at the time of the ambient temp. change is assured. A turn table 6 made of a magnetic metal is attracted to the center spindle of the optical disk device and is fixed to the device body. The adhering and fixing of the magnetic metal flange having the coefft. of thermal expansion different from the coefft. of thermal expansion of the substrates 1, 2 of the optical disk to the substrates are, therefore, obviated and the generation of strains in the substrates 1, 2 at the time of temp. change is prevented. The performance is improved and stabilized in this way and the optical disk device is miniaturized.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to optical discs.

[Conventional technology]

Conventionally, this type of optical disc has a first disc as shown in FIG.
In order to create an air layer between the substrate 1 and the second substrate 2, a non-metallic spacer such as polycarbonate is attached to the outer periphery of the spacer 3.
, is inserted as an inner circumferential spacer 4, and both substrates 1.2 are adhesively fixed, and a magnetic metal flange 7 for a magnetic lamp is adhesively fixed to the outer surface of both substrates 1.2.
It is attracted by a magnet 9 built into a turntable 8 attached to the center spindle of the optical disc device and fixed to the optical disc device.

[Problem to be solved by the invention]

Since the conventional optical disk described above is made of nonmetallic material such as polycarbonate, it cannot be used as is in a magnetic chuck type device, and the magnetic metal flange 7 is adhesively fixed to the substrate in a magnetic chuck type device. However, since the resin substrate and metal, which have large differences in coefficient of thermal expansion, are bonded and fixed, the amount of change in dimensions between the substrate and the magnetic metal flange due to changes in ambient temperature is limited. The difference causes distortion on the board,
There is a drawback that reading and writing information becomes unstable due to changes in the refractive index of the substrate, and in the worst case, it becomes impossible to read or write information.Furthermore, conventional optical disc devices using a magnetic chuck system A magnet for a magnetic chuck is built into the table, and the optical disc is fixed by adsorbing a sharp magnetic metal placed in the center of the outer surface of the optical disc.The magnet is placed between the outer surface of the optical disc and the turntable. The presence of magnetic metals and magnetic metals has been an obstacle to reducing the external dimensions of optical disk devices.

An object of the present invention is to provide an optical disc that solves the above problems.

[Biomembrane to solve problems]

In order to achieve the above object, the optical disc of the present invention includes a first substrate for recording and reproducing information, a second substrate for recording and reproducing information, and the first substrate and the second substrate are adhesively fixed with a constant distance between them. In a double-sided optical disk having an outer circumferential spacer and an inner circumferential spacer, a space consisting of the first substrate, the second substrate, and the inner circumferential spacer is provided with a space larger than the amount of dimensional change due to a change in ambient temperature. It has a built-in magnet.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view showing one example a%J of the present invention.

In the figure, a first substrate 1, a second substrate 2, an outer circumferential spacer 3
, an inner circumferential spacer 4, and a magnet 5. The outer circumferential spacer 3 and the inner circumferential spacer 4 are adhesively fixed to the first substrate 1 and the second substrate 2, and the magnet 5 is fixed to the first substrate 1 and the second substrate. 2
It is built in a space constituted by a spacer and an inner spacer 4 that is larger than the amount of dimensional change due to changes in ambient temperature, and it attracts the magnetic metal turntable 6 of the center spindle of an optical disk device. Fixed to the main body.

Therefore, according to the invention, the substrate 1.2 of the optical disc
There is no need to adhesively fix the substrate and a magnetic metal flange having a different coefficient of thermal expansion to the substrate, and no distortion occurs in the substrate 1.2 when the temperature changes.

〔Effect of the invention〕

As explained above, since the present invention does not bond and fix a substance with a different coefficient of thermal expansion to the substrate of an optical disk, the distortion of the substrate due to dimensional changes caused by the difference in coefficient of expansion does not occur even when the temperature changes, and the refraction of the substrate does not occur. There is no change in performance due to changes in the rate, and economic and time losses are eliminated by relaxing the assembly accuracy of the optical disk and reducing the number of processing steps.
This contributes to improved performance and stability, and also has the effect of reducing the external dimensions of the optical disk device.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional optical disc. 1... First substrate 2... Second substrate 3...
Outer periphery spacer 4... Inner periphery spacer 5... Fig. 1 on magnet Nino 1

Claims (1)

[Claims] (1) Both sides have a first substrate for information recording/reproduction, a second substrate for information recording/reproduction, and an outer circumference spacer and an inner circumference spacer for adhesively fixing the first substrate and the second substrate at a constant distance. An optical disk characterized in that a magnet is housed in a space formed by the first substrate, the second substrate, and an inner circumferential spacer, with a space larger than the amount of dimensional change caused by a change in ambient temperature. .