JPH0739061Y2 - Magneto-optical disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to a magneto-optical disk of a magneto-optical disk device used for an image data file, an external storage device of a computer, etc. A metal having a thickness of 1 to 2 mm, which has a stopper along the outer circumference of the two single-sided magneto-optical disks and has a good thermal conductivity and a low light transmittance for the purpose of preventing the influence. Alternatively, an alloy disc is inserted and bonded.

[Industrial application field]

The present invention relates to a magneto-optical disk of a magneto-optical disk device used as an image data file, an external storage device of an electronic computer, and the like.

The optical disk device is expected to expand its application fields from image data files to external storage devices of electronic computing devices due to its characteristics of large capacity, storability, and high reliability.
However, since rewriting is not possible with an optical disk device, a rewritable magneto-optical disk device is currently under development.

In this magneto-optical disk device, an alloy of iron and a rare earth (terbium, dysprosium, etc.) is generally used as the recording layer. Information is recorded by utilizing the property that the direction of magnetization can be changed by a weak external magnetic field when the recording layer is heated to approach the Curie temperature. Recording is performed by applying a weak external magnetic field in the direction, irradiating only the portion to be recorded with laser light to convert it into heat, and changing the magnetization direction of that portion by approaching the Curie temperature.

When reproducing linearly polarized light on the recording layer, information is reproduced by distinguishing the rotation direction by utilizing the property (Kerr effect) that the vibrating surface of the reflected light rotates right or left depending on the magnetization direction of the recording layer. Identify information by.

Information is erased by applying an external magnetic field in the direction opposite to the magnetic field direction at the time of recording, and reversing the magnetization by bringing the portion to be erased closer to the Curie temperature by laser light.

[Conventional technology]

FIG. 3 is a diagram showing a magneto-optical disk of a conventional magneto-optical disk device. As shown in the figure, a spiral groove 2 serving as a track is formed on the surface of a disk-shaped substrate 1 made of glass, plastic or the like, and a magnetic film (for example, GdFeCo or TbFeCo, etc.), protective layer 5
Are sequentially stacked. Then, the recording layer 4 is formed by the coil 6.
Magnetic recording is performed by irradiating a spot 7 of laser light modulated according to information while applying a weak magnetic field to the laser.

[Problems to be solved by the invention]

The magneto-optical disk as described above is usually a single-sided disk, but it can be used as a double-sided disk by laminating two of them. However, when they are bonded together, there is always a groove-to-groove or land-to-land overlap portion. Therefore, at the time of recording, a magnetic field is also applied to the recording layer on the opposite side, and laser light is irradiated even though it is weak, which may cause noise in the pit information on the opposite side, resulting in a pit error.

In view of the above problems, it is an object of the present invention to provide a magneto-optical disk which is used on both sides and which prevents the influence on the opposite surface during recording.

[Means for solving problems]

The above purpose is to provide a ring-shaped stopper 13 along the outer circumference of the two single-sided magneto-optical disks 10 and 11 in the middle.
A magneto-optical disk characterized in that a metal or alloy disk 12 having a good thermal conductivity and a low light transmittance having a thickness of 1 to 2 mm is inserted and bonded.

[Operation] The metal or alloy disk 12 inserted between the two magneto-optical disks 10 and 11 prevents the laser light projected on one magneto-optical disk from passing to the other, thereby adversely affecting the bit information. It becomes possible to prevent it.

〔Example〕

FIG. 1 is a view showing an embodiment of the present invention, a is a plan view,
b is an enlarged sectional view taken along line bb of FIG.

In this embodiment, as shown in the figure, a metal or alloy (for example, Al, Al alloy) having a thickness of 1 to 2 mm, which has good thermal conductivity and low light transmittance, is provided between two single-sided magnetic optical disks 10 and 11. A disc 12 made of brass or the like) is inserted and adhered by an adhesive, and a ring-shaped stopper 13 is provided on the outer periphery of the disc 12 along the outer periphery of the magneto-optical discs 10, 11. The metal or alloy disc 12 having the stopper 13 may be integrally formed by die casting, pressing, machining, or the like, or the stopper and the disc may be separately formed and then combined and integrated. Anything is fine.

In this embodiment having such a structure, as shown in FIG. 2, when information is recorded on the recording medium 16 of one magneto-optical disk 10 by applying a magnetic field by the coil 14 and the laser beam 15,
By the metal disk 12 inserted between the two magneto-optical disks 10 and 11, the laser light directed to the magneto-optical disk 11 on the opposite side can be blocked, and at the same time, the heat can be radiated. This can prevent the influence on the magneto-optical disk 11 on the opposite side. Further, the stopper 13 increases the bonding strength of the magneto-optical disks 10 and 11, and is also effective for heat dissipation.

[Effect of device]

As described above, according to the present invention, by inserting a metal disc between two magneto-optical discs, it is possible to cut off the laser light that affects the opposite side and to radiate heat. The recording pits of the disc can be stabilized, and the noise of the reproduced signal can be reduced in the magneto-optical disc that is used on both sides.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a usage state of the embodiment of the present invention, and FIG. 3 is a diagram showing a conventional magneto-optical disk. In the figure, 10 and 11 are a magneto-optical disk, 12 is a metal disk, 13 is a stopper, 14 is a coil, 15 is a laser beam, and 16 is a recording layer.

Claims (1)

[Scope of utility model registration request] 1. Two single-sided magneto-optical disks (10, 11)
A metal or alloy disc (12) having a good thermal conductivity and a low light transmittance and having a thickness of 1 to 2 mm, which has a ring-shaped stopper (13) along the outer periphery of the disc, is inserted in the middle of A magneto-optical disk characterized by the above.