JPH02126403A - Magneto-optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To shorten the inversion time of magnetic field generated by an exciting element at the time of recording information by providing a repulsive magnetic field wiring which generates magnetic flux with which leakage flux from an actuator which flows in the exciting element should be cancelled in the exciting element. CONSTITUTION:A magneto-optical disk 4 is rotated and a current corresponding to a signal which should be recorded is inputted in the modulation coil 2 of the exciting element 1 to add the magnetic field to one surface of the disk 4, then a laser light which is projected by a semiconductor laser 13 and whose light intensity is constant is projected to the other surface of the disk 4 to record the information. By projecting only the laser light on the other surface of the disk 4, the variation of the reflected light is detected and recorded information in the disk 4 is reproduced. Meanwhile, the repulsive magnetic field wiring 21 generates the magnetic field of an opposite polarity so that the leakage flux which flows in a yoke 3 caused by the excitation may be cancelled. The magnetic flux PHI2 generated in the repulsive magnetic field circulates through a magnetic pole 3b in the center of the yoke 3 and the leakage flux PHI1 which flows in the yoke 3 is cancelled with the magnetic flux PHI2. The intensity of the magnetic field generated by the exciting element 1 is not changed and the information is recorded on the disk 4 with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magneto-optical recording and reproducing apparatus that records and reproduces information by applying light and a magnetic field to a magneto-optical disk.

[Conventional technology]

FIG. 4 is a schematic perspective view of this type of conventional magneto-optical recording and reproducing apparatus. A magneto-optical disk 4 is rotated by a disk motor 14. Exciting element support arm 1
Information is recorded on the tip side of 5.

An excitation element 1 that generates a bias magnetic field for erasing is attached. This excitation element l is an excitation element support arm 15
by moving the magneto-optical disk 4 in the direction of the arrow.
It moves in the radial direction of the magneto-optical disk 4 while approaching one surface of the disk.

The excitation element l has a modulation coil 2 wound around a central magnetic pole 3b of an E-shaped yoke 3 having three magnetic poles 3a, 3b, and 3c, and the direction in which the magnetic poles 3a, 3b, and 3c are arranged in parallel is magneto-optical. As the track direction of the disk 4, the magnetic pole 3a.

The excitation element is positioned so that 3b and 3c face the magneto-optical disk 4.

On the other hand, an optical pickup 6 is provided which faces the excitation element 1, moves in the same direction in conjunction with the excitation element 1, and is located on the other side of the magneto-optical disk. This optical pickup 6 has a built-in semiconductor laser 13, and an objective lens 7 through which the laser beam of the semiconductor laser 13 passes is provided on the side of the optical pickup 6 facing the excitation element 1. The objective lens 7 of the optical pickup 6 is provided so that it can move close to the other surface of the magneto-optical disk 4.

FIG. 5 is a sectional view of the main parts of the magneto-optical recording and reproducing apparatus. The optical pickup 6 includes an actuator 20 that moves the objective lens 7 along with the semiconductor laser 13 in the optical axis direction. The actuator 20 includes an annular permanent magnet 1
1, a columnar yoke 12a disposed at its axial center position, and an annular yoke 12b disposed at one end of the permanent magnet 11.
An actuator coil 10 is loosely fitted into the columnar yoke 12a, and one shaft end of this actuator coil 10 is attached, and a support shaft 19 protruding from the columnar yoke 12a is slidably provided. It is assembled with the lens support 9 inserted therethrough. The objective lens 7 is attached to one side of the lens support 9, that is, the position where the laser beam of the semiconductor laser 13 is projected, and the lens balancer 8 for stabilizing the lens support 9 in a horizontal state is attached to the other side. There is.

When the actuator coil 1O is excited, this actuator 20 connects it to the columnar yoke 12a and the annular yoke 12b.
An electromagnetic force acts between them, so that the lens support 9 moves in the axial direction of the support shaft 19, and the objective lens 7 moves in the optical axis direction. Then, the excitation current of the actuator coil 10 is controlled in relation to the focal shift of the laser beam projected onto the recording surface 48 of the magneto-optical disk 4, so that the laser beam is always focused on the recording surface 4a. A focus servo operation for moving the lens support 9 can be performed. Note that the focused position of the laser beam is located on the recording surface 4a on the same line passing through the center of the central magnetic pole 3b of the excitation element 1.

Such a magneto-optical recording/reproducing device inputs a current corresponding to a signal to be recorded into a modulation coil 2 of an excitation element 1 to apply a magnetic field to a magneto-optical disk, and also inputs a current corresponding to a signal to be recorded into a modulation coil 2 of an excitation element 1 to apply a magnetic field to a magneto-optical disk.
Information is recorded by projecting a laser beam of constant intensity onto a magneto-optical disk. Further, recorded information is reproduced by projecting only laser light onto the other surface of the magneto-optical disk 4 and detecting fluctuations in the reflected light. Note that when recording information, if information has already been recorded on the magneto-optical disk, it can be erased and new information can be recorded, so that so-called override (overwriting) can be performed.

[Problem to be solved by the invention]

As mentioned above, since the conventional magneto-optical recording/reproducing device uses the permanent magnet 11 in the actuator 20 for focusing servo of the laser beam, the leakage magnetic flux Φ1 is
As shown by the broken line in the figure, the current passes through the magneto-optical disk 4, passes through the yoke 3 of the excitation element 1, and returns to the permanent magnet 11. Therefore, the direction of the leakage magnetic flux Φ and the yoke 3
If the direction of the magnetic field generated within the yoke matches, the magnetic field applied to the magneto-optical disk 4 will become stronger; on the other hand, if the leakage magnetic flux does not match the direction of the magnetic field within the yoke The magnetic field applied to the magneto-optical disk 4 becomes weaker. As a result, there is a problem that the magnetic field does not correspond to the information recorded on the magneto-optical disk 4, resulting in a decrease in recording accuracy. In order to solve such a problem, it is conceivable to flow a current through the modulation coil 2 to offset the leakage magnetic flux Φ1, but in this case, there is a problem that the current in the coil becomes excessive and the excitation element 1 overheats. There is a problem in that it takes a long time to reverse the polarity of the magnetic field.

In view of such problems, it is an object of the present invention to provide a magneto-optical recording/reproducing device in which the recording accuracy of information is not impaired by leakage magnetic flux from the actuator and the polarity reversal time of the magnetic field during information recording is short.

[Failure to solve the problem]

In the magneto-optical recording and reproducing apparatus according to the present invention, a repulsion magnetic field winding that generates a magnetic flux repelling the leakage magnetic flux from the actuator flowing into the excitation element is disposed in the excitation element into which a signal of information to be recorded is input. .

[Effect]

The magnetic field generated by the excitation element is applied to the magneto-optical disk. The repulsion magnetic field winding generates a magnetic field that cancels leakage magnetic flux flowing into the excitation element from the actuator.

This cancels out the leakage magnetic flux that has flowed into the excitation element.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 1 is a schematic perspective view of a magneto-optical recording and reproducing apparatus according to the present invention. The magneto-optical disk 4 is driven by the disk motor 14.
is set to rotate. Exciting element support arm 15
Information is recorded on the lower surface of the tip.

An excitation element 1 that generates a bias magnetic field for erasing is attached. In the excitation element 1, a modulation coil 2 for inputting a signal to be recorded is wound around a central magnetic pole 3b of an E-shaped yoke 3 having three magnetic poles 3a, 3b, and 3c. In this excitation element 1, the direction in which the magnetic poles 3a, 3b, and 3c are arranged in parallel is the track direction of the magneto-optical disk 4, and the magnetic poles 3a, 3b, and 3 are positioned so as to face one surface of the magneto-optical disk.

Further, a repulsion magnetic field winding 21 surrounding the yoke 3 is wound around the upper outer peripheral surface of the yoke 3. This repulsion magnetic field winding 21 is wound with a required number of turns so as to generate a magnetic field that cancels leakage magnetic flux from an actuator 20, which will be described later, flowing into the yoke 3, and is connected to a predetermined excitation power source.

This excitation element l is moved in the radial direction of the magneto-optical disk 4 while approaching one surface of the magneto-optical disk 4 by moving the excitation element support arm 15 in the direction of the arrow perpendicular to the longitudinal direction of the excitation element l. It looks like this.

On the other hand, an optical pickup 6 is provided which faces the excitation element 1 and moves in the same direction in conjunction with it. This optical pickup 6 has a built-in semiconductor laser 13, and an objective lens 7 through which the laser light of the semiconductor laser 13 passes is provided on the side of the optical pickup 6 facing the excitation element 1. The optical pink-up 6 is provided so that the objective lens 7 moves close to the other surface of the magneto-optical disk 4.

FIG. 2 is a sectional view of the main parts of the invention. The optical pickup 6 includes an actuator 20 that moves the objective lens along with the semiconductor laser 13 in the optical axis direction. This actuator 20 includes an annular permanent magnet 11, a columnar yoke 12a disposed at its axial center position, an annular yoke 12b disposed at one end of the permanent magnet 11, and a columnar cork 1.
An actuator coil 10 is loosely fitted to 2a, and one shaft end of this actuator coil 10 is attached, and a support shaft 19 protruding from the columnar yoke 12a is slidably inserted therein. It is assembled with a lens support 9. An example of the lens support 9 is that the objective lens 7 is attached to the position where the laser beam of the semiconductor laser 13 is projected, and a lens balancer 8 that stabilizes the lens support 9 in a horizontal state is attached to the other side. There is.

When the actuator coil 10 is excited, this actuator 20 connects it to the columnar yoke 12a and the annular yoke 12.
An electromagnetic force acts between the lens support 9 and the support shaft 1.
9 to move the objective lens 7 in the optical axis direction. and actuator coil 10
The excitation current is controlled in relation to the focal shift of the laser beam projected onto the recording surface 4a of the magneto-optical disk 4.
Lens support 9 so that the laser beam is always focused at point a
A focus servo operation is performed to move the

Note that the focused position of the laser beam is located on the recording surface 4a on the same line passing through the center of the central magnetic pole 3b of the excitation element 1.

The magneto-optical recording and reproducing apparatus configured in this manner rotates the magneto-optical disk 4, inputs a current corresponding to the signal to be recorded into the modulation coil 2 of the excitation element 1, and applies a magnetic field to one surface of the magneto-optical disk. At the same time, information is recorded by projecting a laser beam of constant light intensity emitted by the semiconductor laser 13 onto the other surface of the magneto-optical disk 4. Furthermore, only the laser beam is projected onto the other surface of the magneto-optical disk, and the recorded information on the magneto-optical disk 4 is reproduced by detecting fluctuations in the reflected light.

Note that when information is recorded, if information has already been recorded on the magneto-optical disk, it is erased and new information is recorded, so that so-called override (overwriting) can be performed.

By the way, the leakage magnetic flux φ1 generated in the permanent magnet 11 of the actuator 20 passes through the magneto-optical disk 4, flows into the central magnetic pole 3b of the yoke 3 of the excitation element 1, and returns to the permanent magnet 11 again through the path shown by the broken line. This will result in reflux.

On the other hand, due to its excitation, the repulsion magnetic field winding 21 causes the yoke 3 to
The leakage magnetic flux that should cancel the leakage magnetic flux that has flowed into the inside generates a reverse radial magnetic field. The magnetic flux Φ2 generated by the repulsive magnetic field flows back through the magnetic pole 3b at the center of the yoke 3, as shown by the dashed line. Therefore, the leakage magnetic flux φ1 flowing into the yoke 3 is canceled out by the magnetic flux φ2 due to the repulsive magnetic field, and the strength of the magnetic field generated by the excitation element 1 does not change due to the influence of the leakage magnetic flux φ1.

Therefore, information can be recorded on the magneto-optical disk 4 with high precision only in relation to the magnetic field caused by the signal input to the modulation coil 2, and a magneto-optical recording/reproducing device with high reliability can be provided. Furthermore, since the magnetic flux that should offset the leakage magnetic flux Φ1 flowing into the excitation element 1 is not generated by passing current through the modulation coil 2, the coil current does not become excessive and the temperature of the excitation element 1 does not rise.

FIG. 3 is a perspective view of the essential parts of another embodiment of the invention. A repulsion magnetic field winding 21 is located on the base side of the central magnetic pole 3b of the yoke 3 of the excitation element 1, and a modulation winding 2 is wound therewith.

In this way, the modulation winding 2 and the repulsion magnetic field winding 'Ia are connected to the same magnetic pole.
Actuator 2 flowing into yoke 3 even if 21 is arranged.
The leakage magnetic flux from the yoke 3 can be canceled out, and the same effect as when the yoke 3 is provided surrounding the yoke 3 can be obtained.

This is effective when the leakage magnetic flux is relatively small.

〔Effect of the invention〕

As detailed above, the present invention can cancel out the leakage magnetic flux flowing into the excitation element from the permanent magnet of the actuator.
The polarity reversal time of the magnetic field generated by the excitation element during information recording can be shortened. Furthermore, since no current is passed through the modulation coil to offset the leakage magnetic flux, the excitation element does not overheat.

Therefore, according to the present invention, it is possible to provide a magneto-optical recording and reproducing device that can record information on a magneto-optical disk with high accuracy, has high reliability, and has a small temperature rise.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a magneto-optical recording and reproducing apparatus according to the present invention, FIG. 2 is a cross-sectional view of the main part of the invention, and FIG. 3 is a perspective view of the main part of the invention showing another embodiment of the invention. , FIG. 4 is a schematic perspective view of a conventional magneto-optical recording/reproducing device, and FIG. 5 is a sectional view of the main part of the device. 1... Excitation element 2... Modulation coil 3...
Yoke 4... Magneto-optical disk 6... Optical pickup 11... Permanent magnet 12b... Annular yoke 13... Semiconductor laser 20... Actuator 21... Repulsion magnetic field winding In the figure, The same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Recording information on one side of the mounted magneto-optical disk;
Magneto-optical recording and reproducing that records and reproduces information by positioning an excitation element that generates a magnetic field for erasure and an actuator that uses magnetic force to adjust the focus of the light projected onto the magneto-optical disk on the other side. A magneto-optical recording and reproducing apparatus, characterized in that the excitation element is provided with a repulsion magnetic field winding that generates a magnetic flux that should offset leakage magnetic flux from the actuator flowing into the excitation element.