JPH06111506A - Magnetic head positioning controller - Google Patents

Abstract

PURPOSE:To enhance durability against impact and vibration and to prevent collision between a magnetic head and a disk by making a positioning means itself possess position holding force. CONSTITUTION:A positioning device 10 is moved integrally with an optical pickup 4 in the radial direction of the disk. The device 10 is fitted with an arm 11, and the arm 11 is fitted with the magnetic head 7 and a position sensor 8. A recording information signal is given to the head 7, where a recording magnetic field is generated. A gap between the disk 1 and the head 7 is detected by the sensor 8, and its detected output is sent to a control device 9. A command signal is sent to the device 10 by the device 9, so as to make the gap between the head 7 and the disk 1 a prescribed value, and the head 7 and the sensor 8 are positioned by the device 10. Then, the positioning device 10 possesses a feed screw for its motor, and this feed screw is fitted with a nut, while the nut is fitted with the arm 11. Consequently, the position is belt by the nut.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head position control device included in a magnetic field modulation recording type magneto-optical disk device.

[0002]

2. Description of the Related Art In a conventional magneto-optical disk drive, at the time of writing, a high-power laser beam emitted from an optical pickup is first applied to a recording film of a magneto-optical disk in a state in which a DC magnetic field is applied, and After erasing the previous data, writing was performed by turning on / off a high-power laser beam while applying a reverse magnetic field.

In recent years, a magnetic field modulation recording technique has been developed in which the conventional erasing operation is unnecessary. In this method, a high-power laser beam emitted from an optical pickup heats a recording film of a magneto-optical disk, and at the same time, a magnetic field is applied at a high speed by a magnetic head to write data. Therefore, there is a great advantage that the erase operation becomes unnecessary, the data writing time can be shortened, and digital voice recording can be performed in real time.

In this case, as described above, since it is necessary to reverse the magnetic field at high speed, it is necessary to reduce the inductance of the magnetic head coil. However, if the inductance is reduced, the number of coil turns decreases,
If the currents flowing through the coils are the same, the magnetic field generated will be small. Therefore, it is necessary to narrow the gap between the magnetic head and the magneto-optical disk. Compact disc (CD)
In the case of a rewritable CD having a format compatibility with a CD-ROM or a CD-ROM, the distance between the magnetic head and the magneto-optical disk is about 0.1-0.2 mm. On the other hand, the surface wobbling and warpage of the magneto-optical disk are as large as about 1 mm, and the fixed magnetic head cannot maintain the distance between the magneto-optical disk and the magnetic head at about 0.1-0.2 mm.

For this reason, a method is used in which the magnetic head is attached to an actuator and is moved in a direction perpendicular to the surface of the magneto-optical disk to control the gap between the magnetic head and the magneto-optical disk to be constant.

Now, a conventional magnetic head position control device will be described with reference to the drawings. FIG. 3 is a block diagram of the magnetic head position control device. The disk 1 is detachably attached to a turntable 2 attached to a spindle motor 3. The optical pickup 4 is connected to a control device (not shown) to position the objective lens in the focus direction and the tracking direction, and at the same time,
The disc 1 is irradiated with a laser beam for recording, or the recorded information is read out. The optical pickup 4 can be moved in the radial direction of the disc 1 by a feeding device (not shown). The magnetic head actuator 6 is connected to the optical pickup 4 via the arm 5, and moves together with the optical pickup 4 in the radial direction of the disk 1. Magnetic head actuator 6
A magnetic head 7 and a position sensor 8 are attached to the. A recording information signal is applied to the magnetic head 7 from the recording device, and a recording magnetic field is generated. The position sensor 8 detects the distance from the disc 1 and the output thereof is connected to the control device 9. The control device 9 gives a command signal to the magnetic head actuator 6 so that the distance between the magnetic head 7 and the disk 1 becomes a predetermined value. The magnetic head actuator 6 positions the magnetic head 7 and the position sensor 8 according to the command signal.

Next, FIG. 4 shows a configuration diagram of a conventional magnetic head actuator 6. On the base 6a, the yoke 6b
Is attached. A magnet 6c is attached to the yoke 6b. Further, a movable portion 6f is attached to the base 6a via a spring 6e. A coil 6d, a magnetic head 7, and a position sensor 8 are attached to the movable portion 6f. A magnetic circuit is formed by the yoke 6 and the magnet 6c. When a current flows through the coil 6d, an electromagnet is generated by the magnetic field in the magnetic circuit and the current flowing through the coil,
The movable portion 6f is displaced.

[0008]

By the way, the magnetic head actuator 6 used in the conventional magnetic head position control device has a structure in which the movable portion is supported by the spring 6e. If a shock is applied from the, the movable part will shake. The distance between the disk 1 and the magnetic head 7 is controlled to be constant. However, since the force that can be generated by the magnetic head actuator 6 is finite, when an impact exceeding that is applied, the movable part shakes greatly and the magnetic head 7 And the disk 1 collide. The same applies when an impact including a high frequency component that exceeds the control band is applied. In this way, when the disk collides with the magnetic head, not only is the disk or magnetic head scratched, but if a collision occurs during recording, the focus and tracking control of the optical pickup will be lost and recording will be interrupted. It happens that the information that has already been recorded is erased.

As described above, the conventional magnetic head position control device has a problem that it is vulnerable to shock and vibration, and a collision between the magnetic head and the disk is likely to occur.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above conventional problems and to provide a magnetic head position control device which is resistant to shock and vibration and does not cause a collision between the magnetic head and the disk.

[0011]

According to the present invention, in a magnetic head position control device included in a magnetic field modulation recording type magneto-optical disk device, a detecting means for detecting a distance between the disk and the magnetic head, and an output of the detecting means. According to the control signal for outputting a command signal so that the distance between the disk and the magnetic head becomes constant, and positioning means for moving the magnetic head according to the command signal, and the positioning means It is characterized by having a holding force.

[0012]

The position sensor detects the distance between the magnetic head and the disk, and the output is sent to the control device. Then, the control device gives a command signal to the positioning device so that the distance between the magnetic head and the disk becomes a predetermined value. A collision between the magnetic head and the disk can be eliminated by providing a mechanism having a position holding force such that the movable parts such as the rack and the nut do not move even if an impact is applied to the positioning device.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic head position control device according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a magnetic head position control device. The disk 1 is detachably attached to a turntable 2 attached to a spindle motor 3.
The optical pickup 4 is connected to the control device, positions the objective lens in the focus direction and the tracking direction, and at the same time, irradiates the disc 1 with a laser beam for recording or reads out the recorded information. To do. Further, the optical pickup 4 can be moved in the radial direction of the disc 1 by a feeding device. The positioning device 10 is integrated with the optical pickup 4 to form the disc 1
Move in the radial direction. The positioning device 10 has an arm 1
1, a magnetic head 7 and a position sensor 8 are attached to the arm 11. A recording information signal is applied to the magnetic head 7 from the recording device, and a recording magnetic field is generated. The position sensor 8 detects the distance from the disk 1, and the output thereof is sent to the control device 9. The control device 9 gives a command signal to the positioning device 10 so that the distance between the magnetic head 7 and the disk 1 becomes a predetermined value.
In response to the command signal, the positioning device 10 moves the magnetic head 7
And position sensor 8 is positioned.

Next, a block diagram of the positioning device 10 is shown in FIG.
Shown in. The motor 10b and the guide shaft 10 are attached to the frame 10a.
d is attached. The motor 10b has a feed screw 1
0c is attached, and further, a nut 10e is attached to the feed screw 10c. Nut 10e
An arm 11 is attached to the. In response to the command signal from the control device 9, the motor 10b rotates and the nut 10
e moves. As a result, the arm 11 attached to the nut 10e also moves.

In the feed screw mechanism shown as the positioning device of the present embodiment, the nut 10e does not move even if an impact is applied from the outside, that is, the position is held, and the deflection of the magnetic head causes the deflection of the arm 11. It is a slight amount due to the above.

In this embodiment, the feed screw mechanism is used as the positioning device, but other mechanisms such as a rack and pinion mechanism using a reduction gear and a ball screw mechanism are also used.
A mechanism in which a movable part such as a rack or a nut does not easily move even when an impact is applied, that is, a mechanism having a position holding force may be used. Alternatively, a positioning device such as a linear pulse motor having a position holding force by the motor itself may be used.

[0018]

As described above in detail, according to the present invention, since the positioning means itself has a position holding force, even if a shock or vibration is applied, the shake of the magnetic head caused by the shock can be suppressed. It is possible to provide a magnetic head position control device in which the magnetic head and the disk do not collide.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a magnetic head position control device showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a magnetic head positioning device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a magnetic head position control device according to a conventional example.

FIG. 4 is a configuration diagram of a conventional magnetic head actuator.

[Explanation of symbols]

 1 Magneto-optical disk 2 Turntable 3 Spindle motor 4 Optical pickup 5, 11 Arm 6 Magnetic head actuator 6a Base 6b Yoke 6c Magnet 6d Coil 6e Spring 6f Moving part 7 Magnet head 8 Position sensor 9 Control device 10 Positioning device 10a Frame 10b Motor 10c Feed screw 10d Guide shaft 10e Nut

Claims (1)

[Claims] 1. A magnetic head position control device included in a magneto-optical disk device of a magnetic field modulation recording system, means for detecting a distance between the disk and the magnetic head, and the disk and the magnetic field according to an output of the detecting means. It is characterized in that it comprises control means for outputting a command signal so that the distance between the heads is constant, and positioning means for moving the magnetic head in accordance with the command signal, and the positioning means has a position holding force. Magnetic head position control device.