JPH0581718A - Cartridge for magneto-optical disk - Google Patents

Abstract

PURPOSE:To obtain the cartridge for a magneto-optical disk which converges the magnetic flux of a magnet for initialization to a magnetic recording medium surface and allows the miniaturization of the magnet for initialization. CONSTITUTION:The cartridge 3 housing the magneto-optical disk which allows overwriting by an optical modulation system and erases recorded information by the magnetic field of the magnet for initialization is constituted by disposing a metallic member 2 having high magnetic permeability to a cartridge plate 3A facing the surface of the magneto-optical disk 1 on the side opposite from the surface facing the magnet for initialization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cartridge for accommodating a magneto-optical disk capable of non-contact overwriting of information by irradiating a disk-shaped surface of a magneto-optical recording medium with a light beam.

[0002]

2. Description of the Related Art Conventionally, a first optical disk forming substrate has been used.
A magnetic film having a double-layered structure including a two-layer recording layer and a second auxiliary layer is provided, and the first recording layer has a lower Curie point than the second auxiliary layer and has a coercive force at room temperature. Use a high magnetic film.

When the magneto-optical disk passes under the initializing magnet, the auxiliary layer is initialized so that the magnetization of the auxiliary layer is aligned in the direction of the magnetic field of the initializing magnet, and the magnetization of the recording layer remains unchanged. In this state, a magneto-optical disk capable of overwriting is being developed.

[0004]

By the way, such an initialization magnet is generally disposed inside the drive unit of the magneto-optical disk, and in order to reduce the capacity of the drive unit as a whole and to make the unit compact, This initialization magnet needs to be made as small as possible.

As shown in FIG. 3 (a), such a magneto-optical disk 1 moves along the direction of arrow A to open and close the magneto-optical disk surface when mounted in a magneto-optical disk drive. It is housed in a plastic cartridge 3 having a stainless steel shutter 6. Then, moisture and dust in the atmosphere are prevented from entering the magneto-optical disk 1.

Inside a driving device (not shown) for mounting and driving this magneto-optical disk, an initialization magnet 4 for initializing the magneto-optical recording medium of the magneto-optical disk and the magneto-optical disk are provided. When the lens 8 of the laser light irradiation device for reading the information of the disk 1 is arranged and the initialization magnet 4 is installed at a position apart from the cartridge 3, the initialization magnet 4 is It is difficult for the magnetic flux to sufficiently reach the surface of the magneto-optical recording medium of the magneto-optical disk 1, and the initialization is insufficient.

Conventionally, a structure in which the magnetic flux of the initialization magnet 4 is concentrated especially on the surface of the magneto-optical recording medium of the magneto-optical disk is not adopted, and the initialization magnet 4 is brought as close as possible to the surface of the magneto-optical recording medium. For this purpose, the shutter 6 of the cartridge 3 is
There is a problem that the degree of freedom with respect to the mounting position of the initialization magnet is reduced because the mounting is performed in the vicinity of.

Further, as shown in FIG. 3 (b), the initialization magnet 4
Even if it is installed near the shutter of the cartridge 3 and at a position close to the surface of the magneto-optical recording medium of the magneto-optical disk 1, a part of the magnetic field of the initialization magnet is not the S pole but the N pole of the magnet. Due to the influence of the magnetic field moving in the direction of, there is a case where the surface of the magneto-optical disk 1 is not reliably reached as shown by the arrow B and the initialization becomes insufficient.

The present invention solves the above-mentioned problems, and makes the magnetic flux of the initialization magnet converge on the surface of the magneto-optical recording medium of the magneto-optical disk with high efficiency, thereby reducing the size of the initialization magnet. The purpose is to

Conventionally, in JP-A-62-52775, a cartridge has been proposed in which the magnetic flux of such a magnet is efficiently converged on the surface of the magneto-optical disk. However, this cartridge is intended for a magneto-optical disk using the magnetic field modulation method, and is different from the magneto-optical disk using the optical modulation method of the present application, and the arrangement configuration of members for converging its magnetic flux is also different.

[0011]

A cartridge for a magneto-optical disk according to the present invention is a cartridge for accommodating a magneto-optical disk which can be overwritten by an optical modulation method and which erases recorded information by a magnetic field of an initialization magnet. Further, a metal member having a high magnetic permeability is arranged on the cartridge plate facing the surface opposite to the magneto-optical disk surface facing the initialization magnet.

The longitudinal dimension of the high-permeability metal member is larger than the radius of the magneto-optical recording medium of the magneto-optical disk.

[0013]

According to the present invention, in a box type cartridge for accommodating a magneto-optical disk, a high permeability metal such as permalloy is provided on the cartridge plate facing the opposite side of the magneto-optical disk surface facing the initialization magnet. By arranging, the magnetic flux of the initialization magnet installed in the vicinity of the cartridge comes to converge in the direction of the high-permeability metal, and the magnetic flux passes through the surface of the magneto-optical disk to cause the magneto-optical disk to move. It becomes possible to efficiently converge on the surface of the recording medium, and the initialization magnet can be downsized.

[0014]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 (a) is a plan view of a magneto-optical recording disk cartridge of the present invention, and FIG. 1 (b) is a sectional view taken along the line AA ′ of FIG. 1 (a).

As shown in FIGS. 1 (a) and 1 (b), the magneto-optical disk cartridge of the present invention is made of a plastic which faces the back side of the magneto-optical disk 1 where the initialization magnet faces. The cartridge plate 3A has a structure in which the metal plate 2 made of permalloy having a high magnetic permeability is embedded. By doing so, the magnetic flux 5 from the initialization magnet 4 passes through the surface of the magneto-optical disk 1 by the metal plate 2, and the magnetic flux 5 of the initialization magnet 4 is efficiently formed on the magneto-optical recording medium formed thereon.
Will arrive.

The metal plate may be embedded in the cartridge plate 3A or may be attached to the cartridge plate 3A. Further, the metal plate is arranged immediately below the initialization magnet when the cartridge is mounted in the magneto-optical disk drive, and is positioned so as not to obstruct the passage of the laser light emitted from the reading head. To be placed.

Incidentally, 6 in FIGS. 1 (a) and 1 (b) is a shutter which automatically opens and closes in the direction of arrow A when this cartridge is mounted in the drive unit of the magneto-optical disk. The laser light from the laser light source for recording and reproduction reaches the magneto-optical disk surface from the opening of the shutter.

Further, as shown in FIG. 2, when the length of the metal plate 2 is longer than the radius of the magneto-optical recording medium 7 of the magnetic film formed on the magneto-optical disk 1, the magneto-optical disk rotates once. In the meantime, the auxiliary layer of the magneto-optical recording medium 7 of the magneto-optical disk can be surely initialized at one time, and the initialization time can be shortened.

[0019]

As described above, according to the magneto-optical disk cartridge of the present invention, the magnetic flux generated from the initialization magnet outside the cartridge can be efficiently converged on the recording medium surface, and the initialization can be performed. The size of the magnet for use can be reduced. In addition, it is not necessary to dispose the initialization magnets in the vicinity of the shutter of the cartridge, which has the effect of increasing the degree of freedom in the arrangement position of the initialization magnets.

[Brief description of drawings]

FIG. 1 is a plan view and a sectional view of a magneto-optical disk cartridge of the present invention.

FIG. 2 is an explanatory diagram showing another embodiment of the present invention.

FIG. 3 is a perspective view and a sectional view of a conventional magneto-optical desk cartridge.

[Explanation of symbols]

 1 magneto-optical disk 2 metal plate 3 cartridge 3A cartridge plate 4 initialization magnet 5 magnetic flux 6 shutter 7 magneto-optical recording medium

Claims (2)

[Claims] 1. A cartridge (3) for accommodating a magneto-optical disk (1) which can be overwritten by an optical modulation method and which erases recorded information by the magnetic field of an initialization magnet, wherein the initialization magnet is A magneto-optical disk cartridge characterized in that a metal member (2) having a high magnetic permeability is arranged on a cartridge plate (3A) facing the side opposite to the surface of the facing magneto-optical disk (1). 2. A metal member (2) having a high magnetic permeability according to claim 1.
A magneto-optical disk cartridge, wherein the longitudinal dimension of the is larger than the radius of the magneto-optical recording medium (7) of the magneto-optical disk (1).