JPH01113940A - System for magnetizing magneto-optical disk - Google Patents

Abstract

PURPOSE:To execute initialization and total deleting independently in each side by heating only one side of a both sides-medium with light irradiation, lowering holding force and independently magnetizing only one side. CONSTITUTION:A magneto-optical disk medium 4 is arranged in the further inner side of xenon flash lamps 2 and 3 to be arranged between two magnetic poles 1 and 1'. When only an magneto-optical disk upper surface 5 is initialized to totally deleted, the xenon flash lamp 2 is emitted from the magnetic poles 1 and 1' in a direction, in which magnetization is desired, in a condition that a magnetic field to be smaller that the coercive force of the magneto-optical disk medium 4 is generated. By the emission of the xenon flash lamp 2, only the magnetic film of the magneto-optical disk upper surface 5 is heated and by a temperature increasing, the coercive force is lowered and the magnetization is executed. Concerning a magneto-optical disk lower surface 6, the xenon flash lamp 3 is emitted and the magnetization is executed in the same theory. Thus, the initialization and total deleting can be executed independently in each side.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magneto-optical disk magnetization method, particularly a method for initializing a magneto-optical disk in the manufacturing process of a magneto-optical disk medium and Magneto-optical disk magnetization method for erasing information all at once [Prior art] In general, information is recorded on a magneto-optical disk medium as shown in Figure 2 (
As shown in a), for example, an unrecorded portion 10 in the magnetic film 7 on the lower surface 6 of the magneto-optical disk consisting of the substrate 8 and the magnetic film 7.
When the magnetization direction of the recording portion 9 is downward, the magnetization direction of the recording portion 9 is upward, and this direction of magnetization is used as information.

Therefore, the direction of magnetization of the lower surface 6 of the magneto-optical disk when no data is recorded must be entirely downward as shown in FIG. 2(b).

However, since the magnetic film 7 is in a demagnetized state during film formation,
The magnetization directions of the magnets are randomly directed upward and downward, as shown in FIG. 2(c).

Therefore, in order to record information on the lower surface 6 of the magneto-optical disk, it is necessary to initialize it to the state shown in FIG. 2(b).

To initialize, an external magnetic field is applied downward as shown in FIG. 2(d), and the field strength of the external magnetic field is changed. Also, information on the magneto-optical disk medium on which information was recorded.
A similar method must be used when performing bulk deletion.

In the conventional magneto-optical disk magnetization method, in order to manufacture a double-sided medium in which two magneto-optical disk media are pasted together, each magneto-optical disk medium is initialized before being pasted together. was.

However, with such a conventional magneto-optical disk magnetization system, bulk erasing is not possible. In other words, when trying to erase double-sided media all at once by applying a magnetic field from the outside,
When an external magnetic field is applied as shown in FIG. 3, the magnetization directions of both the magneto-optical disk upper surface 5 and the magneto-optical disk lower surface 6 in FIG. 3 are directed downward. This turns the top and bottom upside down and points upwards. Therefore, when looking at this magneto-optical disk medium from the direction of the laser beam incident from the optical head of the magneto-optical disk device, the batch erasure direction of the magnetic 1 is different for the upper and lower disks in FIG. To do this, it is necessary to peel each side of the double-sided medium and magnetize it independently.

[Problem that the invention seeks to solve]

As described above, the conventional magneto-optical disk magnetization method has the disadvantage that when erasing information at once, both the upper and lower surfaces must be peeled off and magnetized independently, which is virtually impossible.

[Means for solving problems]

The magneto-optical disk magnetization method of the present invention is a method in which a double-sided medium made by laminating two magneto-optical disks is magnetized in one direction on each side, in which only one side of the double-sided medium is heated by light irradiation. This reduces the holding force and allows only one side to be separated independently.

〔Example〕

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

FIG. 1 is a front view showing an embodiment of the present invention.

The magneto-optical disk magnetization method shown in Figure 1 uses two magnetic poles 1
. The magneto-optical disk medium 4 is double-sided and consists of an upper surface 5 of the magneto-optical disk and a lower surface 6 of the magneto-optical disk.

When initializing or batch erasing only the top surface 5 of the magneto-optical disk, generate a magnetic field smaller than the holding force of the magneto-optical disk medium 4 from the magnetic pole 1' in the direction you want to magnetize, and use the xenon flash lamp 2.
to emit light. The light emitted from the xenon flash lamp 2 heats only the magnetic film on the top surface 5 of the magneto-optical disk, and the coercive force decreases due to the temperature rise, so that only the top surface 5 of the magneto-optical disk is magnetized.

In addition, when initializing or erasing only the lower surface 6 of the magneto-optical disk, the magnetic poles 1 and 1'
The xenon flash lamp 3 is caused to emit light while a magnetic field smaller than the coercive force of the magneto-optical disk medium 4 is generated. As a result, single-crystal phase formation and batch erasing can be performed one side at a time on the same principle as when only the upper surface 5 of the magneto-optical disk is magnetized.

〔Effect of the invention〕

This has the effect of being able to perform periodization and bulk deletion.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2(a)
~(d) shows the magnetization direction of the magneto-optical disk surface when magnetized using the embodiment shown in FIG.
The figure is a magnetization direction diagram showing the magnetization direction of a magneto-optical disk medium when batch erasing is performed on a double-sided medium using the conventional technique. l, 1'...mL 2, 3...Xenon flash lamp, 4...Magneto-optical disk medium, 5...Top surface of magneto-optical disk, 6... ...
...lower surface of magneto-optical disk, 7.7'...magnetic film, 8,8'...substrate, 9...group yK1th Zth

Claims (1)

[Claims] This method heats only one side of a double-sided media made by pasting two magneto-optical disks together with light to lower the coercive force, applies an external magnetic field in a certain direction to independently magnetize only one side, and then irradiates only the other side with light. A magneto-optical disk magnetization method characterized in that magnetization is performed by applying an external magnetic field in a direction opposite to the fixed direction.