JPS61131202A - Thermomagnetic recording system - Google Patents

Abstract

PURPOSE:To perform high-density recording by using a magnetic medium with surfaces which have isotropic magnetic characteristics and storing information in the direction of residual magnetism in the surfaces of the magnetic medium. CONSTITUTION:When desired magnetic information is stored at a desired position in a surface of the magnetic medium 1, light from a light source 11 is controlled by an optical deflector 13 and a light converging device 15 to illuminate the surface of the magnetic medium 1 at the desired position, and one of orthogonal magnetic field generators 3, 5, 7, and 9 is driven to apply the light irradiated part with a magnetic field generated by the orthogonal magnetic field generator in a desired direction. Then, the part irradiated with the light rises in temperature and the coercive force of the magnetic medium 1 decreases at the part, so the magnetism of the magnetic medium 1 at this part is directed in the direction of the magnetic field applied from the orthogonal magnetic field generator. Thus, the direction of the magnetism at this part is set in the desired direction and then the light irradiation is stopped, so that information is stored at this part in the magnetism direction.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a method for reducing coercive force by irradiating light onto the surface of a magnetic t/r medium and increasing the temperature of the light-irradiated portion of the medium. The present invention relates to a thermomagnetic recording method in which a magnetic field is applied to a pre-light distribution irradiated portion to set the magnetization direction of the light irradiated portion in the direction of the applied magnetic field.

[Technical Background and Problems of the Invention] The thermomagnetic recording method has been attracting attention as a means of storing information for a population of 196 years.

This thermomagnetic recording method applies a magnetic field smaller than a coercive force <Xa>J of 1 to the room temperature of the medium to a flat magnetic medium, and irradiates the medium with light focused on a minute diameter. Kosho 4.1
The temperature of the part is 1 - stomach 1! In this method, the direction of magnetization of the light irradiated portion is made to be in the direction of the applied Ifi field by utilizing the decrease in the coercive force of the medium due to temperature fluctuation, and is referred to as a magneto-optical recording method.

1.1, the axis of easy magnetization of the medium is perpendicular to the surface of the medium, and the YIi rectangular inward orientation of the medium surface remains 1! There are two types of recording methods: a vertical thermomagnetic recording method in which the magnetization is reduced, and a horizontal thermomagnetic recording method in which the magnetization remains within the medium plane. Furthermore, depending on the characteristics of the change in coercive force caused by the temperature of the medium material, it can be divided into a cue temperature recording method and a compensation temperature recording method.

For example, recording using Tb-Feta is using the Cured temperature recording type perpendicular thermomagnetic recording method, recording using Gd-Co material is using the Compensated Temperature Recording 51 perpendicular thermomagnetic recording method, and recording using Cr 02 is using the Curing temperature recording type perpendicular thermomagnetic recording method. It is a horizontal thermomagnetic recording method.

In both the J and Una-C methods, the light is narrowed down to a minute slit and the medium is wetted to 1:L/L for recording, so the tracks are higher than that of normal magnetic recording. On the one hand, the Song Dynasty recorded information in a minute area, and if there was a minute defect in the medium,
Previously, there were problems that caused errors. Furthermore, since it is necessary to perform recording and reproduction by accurately positioning in a minute area, there has conventionally been a problem that the optical positioning device is complicated, has a large number of parts and circuit configuration, and is expensive. Furthermore, since the minimum diameter that can condense light is theoretically limited by the wavelength of light, there is also the drawback that it is difficult to further increase the density.

In addition, when looking at recording methods, there are two types: a magnetic field bias type in which recording is performed using O4B, which instantaneously irradiates light while applying a constant magnetic field; Inversion t! There is a thermal bias type that performs C recording, but with the tn lift bias type, it is necessary to erase information before recording new information, and with the thermal bias type, there is a problem that recording density cannot be increased. be.

[Object of the invention] This invention has been made in view of the above-mentioned problems, and the object of (a) is to provide (-11, information record 1) in a high-density cycle and
The purpose of this system is to provide a highly reliable heat recording method.

[Summary of the Invention] In order to achieve the object of L-opening, the present invention provides a magnetic IIv body in which f1 when magnetized is on the iso-directional 2r plane, and a predetermined position r1 on the plane of the front magnetic diagonal body. By having a light beam that condenses the light to a certain size and irradiates it with a single beam, and a magnetic field applying device that applies a magnetic field to the surface at least at the desired position, it is possible to In both cases, the gist is to cause magnetization in a desired direction to remain in the plane of the desired position of the magnetic medium and to emerge in the direction of this magnetization.

[Embodiments of the Invention] Hereinafter, practical examples of the present invention will be explained with reference to the drawings.
1 Fig. 111 shows one embodiment of this invention.
Vine.

In the figure, a flat quadrilateral magnetic medium 1 is an isotropic tl+magnetic material 11, such as polycrystalline 7Fe203itlJll!, which has an isotropic magnetization characteristic in the in-plane direction r of the magnetic medium 1. J
, C0-P alloy thin film, etc. Near each side of the magnetic medium 1, bar-shaped orthogonal magnetic field generators 3, 5, 7.9 are arranged parallel to each Hn. Also,
The surface of the magnetic medium 1 is irradiated with light from the light source 11 that is deflected by the optical deflector 13T' and focused by the condenser 15, and the temperature of the irradiated portion of the magnetic medium 1 is increased by one arm. Natsu-C is here. Therefore, as this temperature approaches the core temperature of the medium, the coercive force of that portion of the magnetic medium 1 decreases.

The orthogonal Ii field generators 3+5r7+9 are each designed to generate a magnetic field in a predetermined direction within the plane of the magnetic medium 1, that is, within the xY plane in the XYZ axes shown in FIG. More specifically, for example, the orthogonal magnetic field generator 3 generates a magnetic field oriented in the positive direction of the Y-axis, the orthogonal magnetic field generator 5 generates a magnetic field oriented in the positive direction of the X-axis, and the orthogonal magnetic field generator 7 generates a magnetic field oriented in the negative direction of the Y-axis. The orthogonal magnetic field generator 9 is oriented 2ffi so as to generate -4=magnetic fields directed in the negative direction of the X-axis. And, the orthogonal magnetic field generators 3, 5, 7.9 are installed in the tlTI equipment (not shown).
One of them is activated under control, and a magnetic field in a predetermined direction generated by the activated orthogonal magnetic field generator is applied within the plane of the magnetic medium 1. Also, in this case, 2
The orthogonal magnetic field generators on the two orthogonal magnetic field generators may be activated simultaneously to combine the vIi fields generated by the two orthogonal magnetic field generators by applying a magnetic field in the direction in which the two orthogonal magnetic field generators are formed to the magnetic medium 1.

In the above configuration J:, in order to store desired magnetic information at a desired position within the plane of the magnetic medium 1, the light from the light source 11 is directed to the optical deflector 13 and the condenser 15.
At the same time, one of the orthogonal magnetic field generators 3, 5, and 7.9 is driven to generate a desired amount of light generated by the driven orthogonal magnetic field generator. A magnetic field in the same direction as above is applied to the light irradiated portion. Then, the temperature of the portion irradiated with the light increases and the coercive force of the magnetic medium 1 in that portion decreases, so that the magnetization of the magnetic medium 1 in this portion is reduced by the magnetic field applied from the orthogonal 11 lift generator. are arranged in the direction of This J: The magnetization direction of the part is arranged in the desired direction in this way, and the light irradiates [111
If it is stopped, information based on the direction of the magnetic field will be stored in that part.

That is, in the thermomagnetic recording device of the present invention, information is stored according to the direction of magnetization.

This is because the conventional method uses magnetization reversal in one direction in a unit storage area, that is, a unit storage area that stores one piece of information, to store two pieces of information (i.e., one bit).
In contrast, in the thermomagnetic recording device of the present invention, information is stored in one unit storage area by one direction of magnetization, and the number of directions of magnetization corresponds to the number of directions of magnetization. A large amount of information can be stored in one unit storage area, and storage capacity can be dramatically increased.

More specifically, if the in-plane magnetization direction of the magnetic medium 1 is controlled to be divided into, for example, 16 directions, that is, divided into 16 directions at equiangular intervals of 22° and 5° and stored. One unit storage area, for example, the minimum intermediate FiL to which the focused light is irradiated! 16 pieces of information in the memory area,
It is possible to memorize information equivalent to 1 to 4 pits,
Also, 6/ with equiangular spacing of 5.5° zu-)! If it is divided in the direction of 1, a considerable amount of information can be stored in 6 bits 1.

Furthermore, in the conventional thermomagnetic recording system 15, I'', Ti1l
Since the presence or absence of information was determined based on the crystal grains, errors were likely to occur if there was a local change in the magnetization of the medium.In contrast, with the present invention, information is stored in the direction of the horns of tJI 111. Since it is 1, C is set to <r so that an error does not occur even when the magnetization of the medium changes. Since the change in magnetization of the medium is a type of fluctuation, it is a principle of statistical mechanics that the smaller the area to be centered, the larger the fluctuation.
In the conventional method, errors increase as the density increases, but in the present invention, information can be stored in the direction of magnetization, and a large amount of information can be stored in one medium storage area.
Therefore, errors caused by changes in magnetization of the medium can be reduced.

Next, a method of reading information stored on the magnetic medium 1 in the direction of magnetization as described above will be explained.

There are various methods for this reading, but the device shown in FIG.
．． 23 respectively to the same desired area of the magnetic medium 1 as two independent linearly polarized beams, and the rotation of the plane of deflection of the light due to the magnetization of the area generated by the magneto-optic effect is converted into each linearly polarized beam. Analyzer 25 which is a compatible analyzer
．． 27, this is detected as an electrical output by a light receiving element 29, 31 consisting of, for example, a phototransistor, and from these two outputs, the angle, that is, the direction of magnetization in the region (J) is detected. Yes. Now, for example, 2
If the directions of irradiation with the two linear polarizations A and B are orthogonal, and these directions are the X and Y directions, and the magnetization direction of the magnetization M is the θ direction when viewed from the X direction, then the magnetization in the X direction is M −
sin θ, rotation of the deflection plane similar to that in the case where the magnetization in the Y direction is M −CO 8 θ occurs in the linear polarizations A and B, and can be detected as the X output and Y output from the light receiving element 31°29. Therefore, the magnetization direction can be determined by orthogonally expressing the output of [3] to this linear deflection. Furthermore, although each electric horn itself is affected by fluctuations in magnetization N4, the magnitude of magnetization can be determined by the following equation, so it can be standardized.

M= [(M-sinθ)2+ (M-cos/7
C be. In addition,
In the above embodiment, the case where the two independent linear deflections are orthogonal horns has been explained, but as long as the two linear deflections are parallel and 11, post-processing such as processing the two outputs in a circuit is necessary. lif& (It is possible to detect the upper side.

Furthermore, in order to store desired information, that is, magnetization in a desired direction, in the magnetic medium 1, a Helmholtz coil or the like disposed outside the magnetic medium 1 is used as shown in FIG. At the same time, a suitable optical device such as a galvanometer mirror 1 ultrasonic deflector is used to position the magnetic medium 1 so as to irradiate the desired position with light. However, it is possible to integrate the orthogonal magnetic field generator and the optical system to make it smaller than the medium, and move this in phase i+ with respect to the magnetic medium, \I! It is difficult to locate the storage position using the

FIG. 3 shows another embodiment of the present invention constructed in this manner. In the figure, a disc-shaped magnetic medium 33 is used, and this disc-shaped magnetic medium 33 is rotated by a spindle motor 35. A device 37 that integrates the above-described orthogonal magnetic field generator and an optical system is disposed adjacent to the lower surface of the magnetic medium 33, and this device 37 is connected to an actuator 39.
The magnetic medium 330 is configured to be able to move in the radial direction as shown by an arrow 41. As a result, as shown in a typical magnetic disk drive, the actuator 39 determines the position of the magnetic medium 33 in the radial direction of the magnetic medium 33 by the actuator 39, and the spindle motor 35 rotates the magnetic medium 330 times to move the sector in the circumferential direction. After determining the storage position on the magnetic medium 33 (J),
Even in the case of 1 person +, ;, F, it is possible to read and write information at a relatively high speed.

Incidentally, the orthogonal 11 j flux generator housed in the above-mentioned device F37 is shown in FIG. J:
Although not shown, the 'V' of this pair of magnetic poles 43, 45
For example, through a magnetic field in a direction perpendicular to the direction of the tk field within the plane of the magnetic body 11 body 33, <1? magnetic pole 43, /
For example, another pair of magnetic poles arranged perpendicularly to I5 are connected to the magnetic poles/13.45 and the magnetic field generating windings/
17. =19 windings, and a magnetic field generating winding is similarly wound around a magnetic pole (not shown) so that a composite magnetic field is applied to the magnetic medium 33 from one side of the magnetic medium 330. In this case, a complete in-plane magnetic field is not generated for the magnetic medium 33, but the center line 5 of the magnetic S optical generator is
In 1, since it is approximately parallel to the surface of the magnetic medium 33, it is sufficient to utilize this part and irradiate the light to this part. A large amount of information can be stored in a region, and the region to be stored at a time may be large, so positioning does not require much precision and the configuration of the device for positioning is simple.

In addition, since the orthogonal magnetic field generator only needs to be able to generate a magnetic field of a predetermined magnitude in any direction within the plane of the magnetic medium 33, it does not need to have a symmetrical structure.
The magnetic head is constructed in such a way that it is generated from the air gap corresponding to the gap of the magnetic head. Then, if this air gap, that is, the air gap between the magnetic poles 43.45, is configured to be several hundred μ or less, and the magnetic pole 43.45 at the tip of the air gap is placed close to the surface of the magnetic medium 330 at about half the air gap length. , 1,000,000, and can reverse this magnetic field at a high frequency similar to a magnetic head.

And said! A thermal bias type in which the direction of magnetization can be determined by controlling the current flowing through the magnetic field generation winding 47.49 while continuously irradiating light toward the magnetic medium 33 from the gap between the i-poles 43.45. This makes it possible to record. In this case, the conventional thermal bias type had the disadvantage of not being able to achieve high recording density as described above, but in the present invention, the recording density can be increased by increasing the number of magnetization directions without reducing the unit recording area. It is now possible to record high-density hemp. Therefore, the optical system is inside the cylinder, and even if there is already recorded information, new information can be stored therein.

Note that the method for determining the direction of magnetization is not limited to the method using 1i field synthesis as in the above embodiment;
For example, the magnetic field generator can be rotated to direct the magnetic field in any direction.

[Effects of the Invention] As explained above, according to the present invention, a magnetic medium having a plane with isotropic magnetization characteristics is used, and information is stored according to the direction of residual magnetization in the plane of the magnetic medium. Therefore, it is possible to perform high-density and ugly recording without reducing the unit storage area by simply increasing the direction of magnetization in the unit storage area, and there is no need to make the unit storage area smaller. Peripheral devices such as positioning devices can be configured inside the cylinder. In addition, there is no need to cut out the 0 region I-buki written at the 111th position. Information is stored by the direction of magnetization, and it is difficult to use magnetization reversal and strength as in the past, so the magnetization A highly reliable storage device that does not cause errors even when changes occur is possible.

4. Simplification of drawings H11t, -; Explanation Figure 1 is an example of this invention M! ! FIG. 2 is a perspective view showing the configuration of a thermomagnetic recording device as an example; FIG. FIG. 4 is a partial configuration diagram of an orthogonal magnetic field generator used in the apparatus of FIG. 3.

1...magnetic medium, 3,5,7.9...orthogonal magnetic field)
1-device, 11... light source, 13... optical deflector, 15.
...Number of condensed light.

゛ko II￥Karigo

Claims (1)

[Claims] a magnetic medium having a surface with isotropic magnetization characteristics; a light irradiation means for irradiating light condensed to a predetermined size to a desired position on the surface of the magnetic medium; and at least to the surface at the desired position. By having a magnetic field applying means for applying a magnetic field,
A thermomagnetic recording method characterized in that magnetization in a desired direction remains in the plane of at least the desired position of the magnetic medium, and information is stored in accordance with the direction of this magnetization.