JPH011102A - Bias magnetic field application device for magneto-optical recording - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bias magnetic field applying device for magneto-optical recording.

[Conventional technology]

FIG. 4 is a configuration diagram showing an outline of a magneto-optical disk drive equipped with a conventional magnetic field applying device using an electromagnet.

In the figure, (1) is a bias magnetic field application device, and this magnetic field application device (1) consists of a core (2) of soft magnetic material, a magnetic pole (3) provided on this core (2), and a magnetic pole (3) provided on this core (2). 3)
It is composed of a coil (4) wound around.

(5) is a magneto-optical recording medium (hereinafter simply referred to as a recording medium) rotated by a spindle motor (not shown),
A magnetized layer (6) and a protective layer (7) that holds this magnetized layer (6).
). (8) is a light converging lens that focuses the light beam emitted from the laser light source (9) as a light source onto the recording medium (5).

The bias magnetic field applying device (1) has no movable part and is capable of simultaneously applying a magnetic field over the entire recording track width of the recording medium (5). For example, JP-A-61-330
The one disclosed in Publication No. 5 and the like is used.

In addition to the above, the magneto-optical disk drive also includes a spindle motor control device, a device that controls the movement of the light spot focused by the light converging lens (8) to a predetermined track on the recording medium (5), and a light spot control device. It is equipped with a device that controls the focus, a photodetector that receives reflected light from the recording medium (5), and converts it into an electrical signal, but these are not directly related to the gist of the present invention. , illustration and description are omitted.

Next, the operation will be explained. Magneto-optical recording methods can be roughly divided into Curie temperature recording and compensation point temperature recording. Magnetized layer (6)
At the same time, a bias magnetic field application device (1
) to apply a bias magnetic field to form reversed magnetic domains, thereby performing recording. The bias magnetic field generates a magnetic field from the magnetic pole (3) by passing a current through the coil (4) by a drive device (not shown).

Note that Curie temperature recording is a method in which the magnetic layer (6) is raised to a temperature higher than the Curie temperature and a reverse magnetic domain is formed by a bias magnetic field or a demagnetizing field of the recording medium. In this method, the temperature of the compensation point is set near room temperature, the temperature of the magnetized layer is raised using laser light, and a reversal magnetic domain is formed using a bias magnetic field by taking advantage of the decrease in coercive force.

[Problem that the invention seeks to solve]

If a conventional bias magnetic field application IT does not have a movable part as shown in Figure 4 above, the magnetic field must be applied simultaneously over the entire recording track width region, making the device larger and requiring more power. And so. Along with this, there have been problems such as an increase in the amount of heat generated. On the other hand, although illustrations and explanations have been omitted, when applying a magnetic field to the laser beam convergence section or °, the °C bias magnetic field application device must be moved in accordance with the movement of the optical system, which complicates the mechanical structure. There were problems such as:

This invention was made to solve the above-mentioned problems, and aims to provide a bias magnetic field applying device S″F with no moving parts and low power.

[Means for solving the problem 1-] A bias magnetic field applying device according to the present invention provides a plurality of magnetic poles so that they can face each other at different positions of a magneto-optical recording medium, and records information on the magneto-optical recording medium. Alternatively, the magnetic poles may be switched depending on the position where recorded information is to be erased.

[For production]

The bias magnetic field applying device of the present invention applies a magnetic field only to the vicinity of the magnetic layer where recording or erasing is being performed by selectively using the magnetic pole near the convergence part of the recording or erasing light, thereby reducing power consumption. .

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is a magnetic field application device with multiple magnetic poles (3
cM3b) (3c) are provided on the same core (2), and each magnetic pole is provided with an independent coil /l/ (4a) (4b) (4
c) is wound.

The rest of the configuration is the same as that of the conventional device described above, so a description thereof will be omitted.

Next, the operation will be explained. Laser light generated from a laser light source (9) is focused onto a minute spot of 1 to 2 μmφ on the magnetized layer (6) of the medium (5) using a light converging lens (8) to raise the medium temperature. In Figure 1, the laser beam is converged on the recording medium (6) at a microspot l-A.
The coil (4b) wound around the magnetic pole (3b) located close to
) by applying a bias magnetic field and forming reversed magnetic domains. During this time, other coils (4a) and (4c)
There is no need for current to flow through.

Also, record or erase on the recording medium (6) at the position i indicated by the broken line.
When performing at point B, switch to the coil (4C) wound around the magnetic pole (3c) near point B and apply lightning or current to the magnetic pole (
A bias magnetic field is applied according to step 3c) to similarly form reversed magnetic domains. During this time, the other coils (4a) and (4b) have l! There is no need to flow the II flow.

As described above, the bias magnetic field applying device of the present invention switches the magnetic poles, that is, the coils, depending on the position of recording information on the recording medium (5) or erasing the recorded information. Even though it forms a magnetic field across the entire width, it requires less power than OK.

In addition, a plurality of coils (4a), (4b), and (4c)
The means for appropriately switching according to the position of the track on the recording medium (5) is not special, and any conventional means may be used as appropriate.

Although Fig. 1 above shows the case where the surfaces of the gaps between the magnetic poles are parallel, it is also possible to construct a structure in which a step is provided between each magnetic pole as shown in Fig. 2. In this way, the distribution of the magnetic field generated from each magnetic pole can be made more uniform.

Further, as shown in FIG. 3, the core can be formed into a U-shape. In this case, the magnetic path becomes shorter and the same magnetic field can be applied with less door flow.

By the way, in the above embodiment, the case where three magnetic poles are provided has been described, but it is needless to say that the present invention is not limited to this.In short, the effect of the present invention can be achieved by using two or more magnetic poles. Furthermore, it is natural that the shape and structure of the magnetic poles are not limited to those of the above embodiments.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of magnetic poles are provided at different positions of the magneto-optical recording medium so as to be able to face each other, and the magnetic poles are provided in a plurality of magnetic poles so as to be able to face each other at different positions on the magneto-optical recording medium. Since the magnetic poles are configured to be switched and used, it is possible to obtain a bias magnetic field applying device with low power consumption and no moving parts.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of a magneto-optical disk drive using a magneto-optical recording/reproducing head bias magnetic field application device according to an embodiment of the present invention, and FIGS. FIG. 4 is a perspective view showing a main part of the embodiment, and FIG. 4 is a configuration diagram showing a magneto-optical disk drive using a conventional bias magnetic field applying device. (1) is a bias magnetic field applying device, (3aL (3b), (
3c) is a magnetic pole, (4aL (4bL (4c) is a coil, (
5) is a magneto-optical recording medium. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. 1 Figure 5 - Photomagnetic) View 4 Roasted Floor Sale 2 Figure Sale 3 Procedural Amendment Document November 10, 1986

Claims (1)

[Claims] A plurality of magnetic poles are provided at different positions of the magneto-optical recording medium so that they can face each other, and the magnetic poles are switched and used according to the position of recording information on the magneto-optical recording medium or erasing recorded information. A bias magnetic field applying device for magneto-optical recording characterized by: