JPH0877634A - Magneto-optical disc apparatus - Google Patents

Abstract

PURPOSE: To reduce the turning time of a permanent magnet which is provided for reversing an external magnetic field with which data are recorded on/erased from a magneto-optical disc and realize the high speed access of the recording/ erasing of data. CONSTITUTION: A magneto-optical disc apparatus has an optical pickup 2 with which an optical head 21 can be moved relatively to a magneto-optical disc DISK and an external magnetic field forming device 5 which generates an external magnetic field HX applied to the magneto-optical disc DISK. A part of a magnetic field HL which is produced by a magnetic driving mechanism (linear motor mechanism 3) is leaked to the external magnetic field forming device 5 as a magnetic field in parallel with a data recording surface. The external magnetic field forming device 5 puts an external magnetic field permanent magnet 54 which is provided for forming an external magnetic field HX into a neutral state by the leakage magnetic field HL. A current is selectively applied to a magnetic field reversing coil 55 in the reverse direction to turn the external magnetic field permanent magnet 54 by a quarter of a turn from the neutral state in the reverse direction to reverse the external magnetic field HX.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical disk device, and more particularly to an external magnetic field forming device for forming an external magnetic field in a different magnetic field direction on the magneto-optical disk when recording or erasing data on the magneto-optical disk. The present invention relates to a magneto-optical disk device.

[0002]

2. Description of the Related Art A magneto-optical disk apparatus changes the magnetization direction inside the magneto-optical disk by heating with a laser beam or the like while forming an external magnetic field on the magneto-optical disk to record and erase data. It is known. For example, assuming that the magneto-optical disk DISK is uniformly magnetized downward as shown in FIG. 6A, the external magnetic field forming device 100 forms an upward external magnetic field HX. If the optical pickup device 101 irradiates a predetermined region of the magneto-optical disk DISK with the laser light L and heats it to a predetermined temperature (Curie point: 400 ° C.) or more, the magnetization direction of the heated portion is along the external magnetic field HX. It is changed upward. Therefore, the magnetization direction of this area is different from that of the other areas, and it is possible to record data based on this magnetization direction.

When erasing recorded data, a downward external magnetic field HX is formed on the magneto-optical disk DISK by the external magnetic field forming device 100, as shown in FIG. 6B. Similarly, by heating with the laser beam L, the magnetization direction of this heated portion can be changed downward, and the heated portion has the same magnetization direction as the other regions, so that data is erased.

As described above, the magneto-optical disk device requires an external magnetic field in different directions for recording and erasing data, so that a device for reversing the external magnetic field has been conventionally proposed. For example, Japanese Examined Patent Publication 5-60162
In the publication, as shown in the schematic structure of FIG. 7, a permanent magnet 200 for forming an external magnetic field with respect to the magneto-optical disk DISK is eccentrically supported so as to be rotatable about an axis. By switching the energizing direction to the coil 201 surrounding the permanent magnet 200, the repulsive force between the magnetic field of the permanent magnet 200 and the magnetic field generated in the coil 201 is used to rotate the permanent magnet 200 by 180 degrees, which causes the permanent magnet 200 to rotate. In this configuration, the direction of the external magnetic field HX formed on the magneto-optical disk DISK is reversed to record and erase data in each external magnetic field. 202 is an optical pickup device.

[0005]

However, the one proposed in this publication requires a physical operation of rotating the permanent magnet around the axis when reversing the external magnetic field. In this example, the permanent magnet is 180
Since it is necessary to rotate once, that is, half rotation, it takes time to complete the operation, and during that time, recording and erasing of data on the magneto-optical disk cannot be performed.
Therefore, the so-called access time for recording and erasing these data is limited by the physical operating time of the permanent magnet,
There is a problem that it becomes an obstacle to speeding up the access time.

In consideration of such an access time, it is advantageous to construct the external magnetic field forming device with a coil and reverse the external magnetic field by switching the direction of energizing the coil. Is disadvantageous in terms of power consumption as compared with the one using a permanent magnet because it is necessary to pass a relatively large current through the coil.

An object of the present invention is to provide a magneto-optical disk device equipped with an external magnetic field forming device which shortens the rotation time of a permanent magnet for forming an external magnetic field and enables a faster access time in the magneto-optical disk device. To provide.

[0008]

A magneto-optical disk device of the present invention is a magneto-optical disk capable of recording and erasing data, and an optical head in which an optical head is movable in a radial direction with respect to the magneto-optical disk. In a magneto-optical disk device including a pickup and an external magnetic field forming device that forms an external magnetic field with respect to the magneto-optical disk in a region where the optical head is moved, the optical pickup uses magnetism as a mechanism for moving the optical head. A magnetic drive mechanism is provided and a part of the magnetic field generated by the magnetic drive mechanism is leaked to an external magnetic field forming device to form a leakage magnetic field in a direction parallel to the data recording surface of the magneto-optical disk. The external magnetic field forming device rotates an external magnetic field permanent magnet for forming an external magnetic field on the magneto-optical disk and the external magnetic field permanent magnet. And a magnetic field reversing coil to form a magnetic field of order, characterized by being configured to be able to selectively reverse current to the magnetic field reversing coil.

Here, when the magnetic field reversing coil is not energized, the external magnetic field permanent magnet is at a rotational position in which the S pole and N pole of the permanent magnet for the external magnetic field are oriented in a direction parallel to the data recording surface of the magneto-optical disk. A rotating position of the permanent magnet for an external magnetic field, which is held by the magnetic field formed by this coil when the coil for magnetic field reversal is energized, is oriented with its south pole or north pole facing perpendicularly to the data recording surface of the magneto-optical disk. The configuration is

For example, the magneto-optical disk device of the present invention is
A magneto-optical disk capable of recording and erasing data, a guide rail extending in the radial direction on one surface side of the magneto-optical disk, and one surface of the magneto-optical disk moved on the guide rail. Side including an optical head for irradiating a laser beam from the side, and a permanent magnet for moving the optical head on the guide rail. A linear motor mechanism that forms a leakage magnetic field in a direction parallel to the recording surface, and is extended along the moving area of the optical head within the leakage magnetic field on the other surface side of the magneto-optical disk, and is perpendicular to the length direction. The permanent magnet for the external magnetic field, which is rotatably supported in the direction, and the permanent magnet for the external magnetic field. A magnetic field of opposite Te and a magnetic field reversing coil.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a schematic perspective view showing an overall configuration of an embodiment of a magneto-optical disk device to which the present invention is applied, FIG. 2 is a partially cutaway plan view, and FIG. 3 is a sectional view taken along line AA. The magneto-optical disk DISK is set in the rotation drive unit 1, and when the rotation drive unit 1 is rotated by the rotation mechanism 11 using a motor (not shown) as a drive source, the magneto-optical disk DISK is rotated and driven at a high speed. Is composed of. Optical pickup 2
On the lower surface side of the magneto-optical disk DISK, from the position near the rotation drive unit 1 to the magneto-optical disk DISK.
Of the magnetic drive mechanism, that is, the linear motor mechanism 3 in this embodiment, is arranged so that the optical head 21 can reciprocate in the radial direction of the magneto-optical disk DISK.

That is, the optical pickup 2 has a pair of rod-shaped guide rails 22 which are longer than the radial dimension along the radial direction of the magneto-optical disk DISK on the lower surface side of the data recording surface of the magneto-optical disk DISK. Are extended in parallel, and support members 23 provided at both ends thereof
It is fixedly supported by the base 4 of the magneto-optical disk device. Further, the slider 2 is attached to the pair of guide rails 22.
4 is inserted and is supported via rollers 25 which are rolled on these guide rails 22, whereby the slider 24 is supported so as to be capable of reciprocating along the guide rails 22. An optical head 21 is mounted on the slider 24. Here, the optical head 21 shows an example in which a laser element 26 and its optical system 27 are integrally formed, and a detailed description thereof will be omitted. The laser light from the laser element 26 is focused by an optical system 27 to irradiate an extremely narrow area on the lower surface of the magneto-optical disk DISK, and this area can be heated to the predetermined temperature.

A linear motor mechanism 3 is arranged on both outer sides of the guide rail 22, and the optical head 21 is guided by the linear motor mechanism 3 by the linear motor mechanism 3.
It is reciprocated on the top 2. The linear motor mechanism 3 includes guide rails 22 on both outer sides of the guide rails 22.
A center yoke 31 extending parallel to the center yoke 31, a back yoke 32 integrated with the center yoke 31, and a center yoke 31 fixed to the back yoke 32.
And a coil 34 attached to the slider 24 in a state of being loosely fitted to the outer periphery of the center yoke 31. The yokes 31 and 32 are fixedly supported on the base 4 by a supporting member 35.

In the linear mode mechanism 3, the permanent magnet 33 is used.
By energizing the coil 34 in the magnetic field formed by the yokes 31 and 32, a magnetic driving force corresponding to the energizing direction is generated in the coil 34, and the energizing amount and energizing direction of the coil 34 are controlled. Then, the coil 34 and the slider 24 and the optical head 21 integrated with the coil 34 are attached to the guide rail 22.
It is possible to move along with and stop at any position. Here, as shown in FIG. 3, the permanent magnets 33 are formed such that the S poles and the N poles of the respective permanent magnets 33 are oriented in the same horizontal direction, and as a result, the respective yokes 31 are formed. , 32 and the permanent magnet 33 form a magnetic field shown by a chain line in the figure in a space region including the guide rail 22 and the optical head 21.

On the other hand, in the upper region of the magneto-optical disk DISK, an external magnetic field forming device 5 is extended in the radial direction of the magneto-optical disk DISK so as to face the optical pickup 2. This external magnetic field forming device 5
Is a base plate 51 and a cover plate 52 extending on the magneto-optical disk DISK, as shown in a partially exploded view in FIG.
Are fastened together by screws 53 to form a flat casing, and an external magnetic field permanent magnet 54 and a magnetic field reversing coil 55 are housed in this casing. The external magnetic field forming device 5 is supported by an opening / closing lid or an upper base of the magneto-optical disk device, although not shown.

Opening grooves 51a and 52a are formed in the base plate 51 and the cover plate 52 along the radial direction of the magneto-optical disk DISK, and these opening grooves 51 are formed.
The external magnetic field permanent magnet 54 in the form of an elongated quadrangular prism facing the a and 52a is supported over the entire radial direction of the magneto-optical disk. Here, the opening grooves 51a and 52a and the permanent magnet 54 for the external magnetic field are provided at positions facing the trajectory of the optical head 21 of the optical pickup 2 in the radial direction. Further, the external magnetic field permanent magnet 54 has a rectangular cross section perpendicular to the lengthwise direction, and its opposing long side is S.
It is formed as a pole and an N pole. The external magnetic field permanent magnet 54 is covered with a resin-made holding member 56 having a circular cross section, and the holding member 56 is provided.
Shafts 56a projecting from both ends in the axial direction are axially supported by the bearing 57 on the inner surface of the cover plate 52. As a result, the external magnetic field permanent magnet 54 is rotatable with the holding member 56 in the direction around the axis thereof, in other words, is rotatable in the vertical plane about the shaft portion 56a of the holding member 56.

In the casing, the magnetic field reversing coil 55 is arranged so as to horizontally surround the external magnetic field permanent magnet 54, and is fixedly supported between the base plate 51 and the cover plate 52. Has been done. The magnetic field reversing coil 55 is energized via a control circuit (not shown), and is controlled so that the energizing directions are opposite when recording and erasing data on the magneto-optical disk DISK. In addition, other than that, for example, the current is not supplied at the time of reading.

Therefore, in the magneto-optical disk device having this structure, the magneto-optical disk DISK is magnetized downward in advance as shown in FIG. 5A, and the magneto-optical disk DISK is rotated by the rotary drive unit 1. Set to
It is supposed to be rotatable. At this time, the permanent magnet 3 of the linear motor mechanism 3 attached to the optical pickup 2
A part of the magnetic field formed by 3 is leaked to the outside of the optical pickup 2 as a leak magnetic field HL through the magneto-optical disk DISK. Magnetic field H in parallel direction
L will be formed. Therefore, in the external magnetic field forming device 5, the external magnetic field permanent magnet 54 is affected by the magnetic force due to the leakage magnetic field HL in a state in which the magnetic field reversing coil 55 is not energized, and the S pole and N pole thereof are leaked magnetic fields It is oriented in a horizontal, or neutral, position along HL. Therefore, the external magnetic field HX formed by the external magnetic field permanent magnet 54 is not applied in the direction perpendicular to the surface of the magneto-optical disk DISK.

When the magnetic field reversing coil 55 is energized in one direction from this state as shown in FIG. 5B, the magnetic field reversing coil 55 forms a magnetic field HC. Since the strength of this magnetic field HC has a relationship of HC >> HL as compared with the strength of the leaked magnetic field HC, the external magnetic field permanent magnet 5
4 is greatly affected by the magnetic field HC of the magnetic field reversing coil 55, and as a result, the external magnetic field permanent magnet 54 is rotated counterclockwise about the bearing 57 by ¼ in the counterclockwise direction in FIG.
The south pole and the north pole are oriented in the direction perpendicular to the data recording surface of the magneto-optical disk DISK. Therefore, the external magnetic field HX having the magnetization direction directed upward by the external magnetic field permanent magnet 54 is applied to the magneto-optical disk DISK.

On the other hand, in the optical pickup 2, by applying a predetermined current to the coil 34 of the linear motor mechanism 3, the optical head 21 is moved on the guide rail 22 by the operation of the linear motor, and a predetermined amount with respect to the magneto-optical disk DISK. Is moved to the radial position of. Then, by converging the laser beam L at this position and irradiating it on the surface of the magneto-optical disk DISK, the magnetization direction in this portion is changed upward, whereby data is recorded on the magneto-optical disk DISK. Is possible. If the energization of the magnetic field reversing coil 55 is stopped at the same time as the recording of the data is completed, the magnetic field affected by the external magnetic field permanent magnet 54 is only the above-mentioned leakage magnetic field HL.
4 is rotated 1/4 clockwise to return to the state of FIG.

On the other hand, as shown in FIG. 5 (c), when the magnetic field reversing coil 55 is energized in the opposite direction, the magnetic field HC generated by the magnetic field reversing coil 55 is also in the opposite direction. The magnetic field permanent magnet 54 is rotated by 1/4 clockwise about the bearing 57, so that the S pole and the N pole are vertically reversed. Therefore, the magneto-optical disk DI
An external magnetic field HX whose magnetization direction is directed downward by the external magnetic field permanent magnet 54 is applied to SK. Then, the optical pickup 2 is connected to the linear motor mechanism 3
When the laser beam L is irradiated after being moved to the position where the data is recorded, that is, the position where the magnetization direction is directed upward, the magnetization direction of the part is directed downward and is recorded on the magneto-optical disk DISK. Data will be deleted.

Therefore, in this external magnetic field forming apparatus 5, the external magnetic field permanent magnet 54 is normally set in its neutral state, and when recording and erasing data, the neutral state is changed clockwise and counterclockwise, respectively. By rotating ¼, it is possible to generate external magnetic fields for recording and erasing on the magneto-optical disk DISK. For this reason, the rotation angle for rotating and setting the external magnetic field permanent magnet 54 from the neutral position to the recording state or the erasing state can be reduced to 1/2 as compared with the conventional structure described in the above-mentioned publication, and thus the access time can be reduced. Can be reduced to 1/2, and high-speed access can be realized in the magneto-optical disk device.

Further, in this configuration, the leakage magnetic field HL of the permanent magnet 33 of the linear motor mechanism 3 is used to make the external magnetic field permanent magnet 54 in a neutral state. However, since the leakage magnetic field HL has a small strength, Even if only a small current is passed through the magnetic field reversing coil 55, a magnetic field HC larger than the leakage magnetic field can be generated to drive the external magnetic field permanent magnet 54 to rotate, so that the current consumption in the magnetic field reversing coil 55 is reduced. It can be extremely small.

Here, in the above embodiment, the optical pickup 2
Although a linear motor mechanism is used as a mechanism for driving the optical head 21, the magnetic field for generating the magnetic force is part of the external magnetic field if the mechanism drives the optical head by using the magnetic force. The present invention can be applied by leaking to the forming device. If the direction of the SN pole of the permanent magnet of the linear motor mechanism is reversed from that of the above embodiment, the rotation direction of the permanent magnet for the external magnetic field is opposite to that of the embodiment, and the recording and erasing operations are performed. Can be made.

[0025]

As described above, according to the present invention, a part of the magnetic field generated by the drive mechanism using magnetism for moving the optical head is a leakage magnetic field in a direction parallel to the data recording surface of the magneto-optical disk. As an external magnetic field forming device, and the external magnetic field forming device uses an external magnetic field permanent magnet for forming an external magnetic field on the magneto-optical disk and a magnetic field for rotating the external magnetic field permanent magnet. And a magnetic field reversing coil for forming a magnetic field reversing coil, and the magnetic field reversing coil can be selectively energized in the opposite direction. It is possible to maintain the neutral state and form the external magnetic fields for data recording and erasing by rotating the external magnetic field permanent magnet by 1/4 in accordance with the direction of energization to the magnetic field reversing coil. Therefore, the rotation time of the permanent magnet for the external magnetic field can be halved as compared with the case where the permanent magnet is rotated by half, and the access time at the time of recording and erasing data can be shortened and the access speed can be increased. You can

Particularly, when the coil for magnetic field reversal is not energized, the permanent magnet for the external magnetic field has its S pole and N pole due to the leakage magnetic field.
The pole is held in a neutral rotating position oriented in a direction parallel to the data recording surface of the magneto-optical disk, and when the magnetic field reversing coil is energized, the magnetic field formed by this coil causes the external magnetic field permanent magnet to have its S pole. Alternatively, by arranging the N pole at a rotational position directed in a direction perpendicular to the data recording surface of the magneto-optical disk, the external magnetic field permanent magnet is rotated in its neutral state at the time of recording and erasing data. By making a quarter turn from the position in different directions,
It is possible to form an external magnetic field in each.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a magneto-optical disk device to which the present invention is applied.

FIG. 2 is a plan view in which a part of FIG. 1 is cut away.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a partially exploded perspective view of an external magnetic field forming device.

FIG. 5 is a schematic cross-sectional view at the same cross-sectional position as in FIG. 4 for explaining the reversal operation of the external magnetic field.

FIG. 6 is a schematic diagram for explaining a recording operation and an erasing operation in a magneto-optical disk.

FIG. 7 is a schematic cross-sectional view of an example of a conventionally proposed external magnetic reversal device.

[Explanation of symbols]

 DISK Magneto-optical disk 1 Rotational drive unit 2 Optical pickup 3 Linear motor mechanism 5 External magnetic field forming device 21 Optical head 22 Guide rails 31, 32 Yoke 33 Permanent magnet 34 Coil 54 External magnetic field permanent magnet 55 Magnetic field reversing coil 57 Bearing HL Leakage Magnetic field HC Magnetic field of magnetic field reversing coil HX External magnetic field

Claims (3)

[Claims] 1. A magneto-optical disk capable of recording and erasing data, an optical pickup having an optical head movable in a radial direction with respect to the magneto-optical disk, and the optical head in a region where the optical head is moved. In a magneto-optical disk device including an external magnetic field forming device that forms an external magnetic field with respect to a magneto-optical disk, the optical pickup includes a drive mechanism using magnetism as a mechanism for moving an optical head, and A part of the generated magnetic field is leaked to the external magnetic field forming device to form a leakage magnetic field in a direction parallel to the data recording surface of the magneto-optical disk. An external magnetic field permanent magnet for forming an external magnetic field on the disk and a magnetic field forming a magnetic field for rotating the external magnetic field permanent magnet. A magneto-optical disk device comprising a field reversing coil, which is configured to be selectively energizable in a reverse direction to the magnetic field reversing coil. 2. A permanent magnet for an external magnetic field, when the magnetic field reversing coil is not energized, has its S pole and N pole due to the leakage magnetic field.
The pole is held at a rotational position directed in a direction parallel to the data recording surface of the magneto-optical disk, and when the coil for magnetic field reversal is energized, the external magnetic field permanent magnet has its S pole or N pole by the magnetic field formed by this coil. 2. The magneto-optical disk device according to claim 1, wherein is a rotational position oriented in a direction substantially perpendicular to the data recording surface of the magneto-optical disk. 3. A magneto-optical disk capable of recording and erasing data, a guide rail extending in the radial direction on one surface side of the magneto-optical disk, and the magneto-optical disk moved on the guide rail. An optical head for irradiating a laser beam from one surface side of the disk, and a permanent magnet for moving the optical head on the guide rail are included, and by this permanent magnet, an area on the other surface side of the magneto-optical disk is provided. A linear motor mechanism that forms a leakage magnetic field in a direction parallel to the data recording surface of the magneto-optical disk; and an extension arrangement along the moving area of the optical head in the leakage magnetic field on the other surface side of the magneto-optical disk, In addition, the permanent magnet for an external magnetic field, which is rotatably supported in the direction perpendicular to the lengthwise direction, and the permanent magnet for an external magnetic field are arranged so as to surround the permanent magnet for the external magnetic field. And a magnetic field reversing coil for forming a magnetic field in the opposite direction to the external magnetic field permanent magnet.