JPH02156446A - Magneto-optical disk medium - Google Patents

Abstract

PURPOSE:To improve the position accuracy of an index signal by including the index signal generating region where the magnetization of a recording layer is set in the direction different from the other part in one circumference of the disk into the region outside the data recording region of a disk substrate. CONSTITUTION:The index signal (a) is obtd. at the time of rotation of the magneto-optical disk medium with respect to the output signal OUT to a disk rotating angle theta when the circumference including the index signal generating region is irradiated with the light of linearly polarized light and the reflected light thereof is detected through an analyzer. This index signal generating region 4 does not require mechanical registration and can be formed by electrically applying magnetic fields thereto and, therefore, the position accuracy is excellent and the disk which is good in appearance is obtd. Further, the detection with the optical head is possible by moving the optical head on the circumference including the index signal generating ration of the magneto-optical disk medium even if the magneto-optical disk device using this magneto-optical disk medium does not have the detecting optical system to be exclusively used for index detection as far as the device has a rotation detecting encoder or rotation clock circuit.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to magneto-optical disk media.

[Conventional technology]

When obtaining an index signal, which is a rotation synchronization signal, in a conventional magneto-optical disk medium, as shown in FIG. Reflective tape 8 as shown
This was obtained by changing the intensity of reflected light from the magneto-optical disk medium. (Patent application announcement 1986
See -24860. ) [Problems to be Solved by the Invention] However, in such conventional magneto-optical disk media, when an index signal generation area with different reflectance is provided in a part of the disk substrate, a mask is used when forming the recording film. It is necessary to create an area without a recording film, and when the mask position and the position of the disk substrate are aligned during disk film formation, the film forming operation becomes complicated, and the appearance is also unfavorable.

In addition, when applying reflective tape to a part of the disk substrate, the work is complicated when applying the tape and aligning the position of the disk substrate during disk film formation.
There is a drawback that if the reflective tape comes off, the recorded data cannot be reproduced.

[Means to solve the problem]

The magneto-optical disk medium of the present invention includes, in an area other than the data recording area on the disk substrate, an index signal generation area in which the magnetization direction of the recording layer is set in a direction different from that in other parts of the disk. be done.

〔Example〕

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

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

The magneto-optical disk medium shown in FIG. 1 includes a disk substrate 1, a recording layer deposition area 2, a data recording area 3, and an index signal generation area 4.

The index signal generation region 4 has a magnetization direction different from other regions, as shown in FIG. 2, which is a longitudinal cross-sectional view of the magneto-optical disk medium shown in FIG.

Therefore, the linearly polarized light is transmitted to the index signal generation area 4.
When the reflected light is detected through an analyzer, it is possible to obtain an index signal a as shown in FIG. 3 when the magneto-optical disk medium rotates with respect to the output signal OUT corresponding to the disk rotation angle θ. can.

This index signal generation area 4 does not require mechanical alignment and can be created by electrically applying a magnetic field, so it is possible to provide a disk with excellent positional accuracy and a clean appearance.

Furthermore, if a magneto-optical disk device using the magneto-optical disk medium according to the present invention has a rotation detection encoder or a rotation detection clock circuit, the optical head can be connected to the magneto-optical disk without having a detection optical system dedicated to index detection. An index signal can be obtained by moving on the circumference of the medium that includes the index signal generation area and detecting it with an optical head.

〔Effect of the invention〕

The magneto-optical disk medium of the present invention has an area in which the magnetization direction of the recording layer is set in a direction different from other areas within one circumference of the disk, so that the positional accuracy of the index signal is excellent and the appearance is excellent. This has the effect of eliminating the need for an optical system dedicated to index detection in the device.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing one embodiment of the present invention, and Fig. 2 is a plan view showing an embodiment of the present invention.
FIG. 3 is a waveform diagram of an index signal obtained from the index signal generation region shown in FIG. 1; FIG. 4 is a plan view of a conventional example; FIG. The figure is a plan view showing another conventional inversion. DESCRIPTION OF SYMBOLS 1... Disc substrate, 2... Recording layer film formation area, 3... Data recording area, 4, 7...
... Index signal generation area, 5 ... Substrate, 6 ... Recording layer, 8 ... Reflective tape, OUT ... Output signal, θ ... ...Disk rotation angle, a... Index signal. Agent Patent Attorney Shinboku Uchihara 3 drawings and 5 drawings

Claims (1)

[Claims] A disk substrate, a recording layer film forming area formed on the disk substrate, a data recording area for recording data formed on the recording layer forming area, and a recording layer forming area formed on the recording layer forming area. A magneto-optical disk medium comprising: an index signal generation area formed below the data recording area and having a magnetization direction set in a direction different from that of other areas within one circumference of the disk.