JPH05225733A - Controlling device for driving magnetic head - Google Patents

Abstract

PURPOSE:To diminish the power consumption in a magnetic head positioning control of a magneto-optical recording and reproducing device and to prevent collision of a magneto-optical recording medium against a magnetic head at the time of loading or unloading the magneto-optical recording medium. CONSTITUTION:When the magneto-optical recording medium is loaded into a recording or reproducing position or unloaded from there in the magneto- optical recording and reproducing device of a magnetic field modulation system, a switch 8 of a servo loop for controlling a distance between the magnetic head and the magneto-optical recording medium to be constant is turned off by a control circuit 5. Then, the magnetic head is controlled to be driven based on a driving signal (PWM signal) for driving the magnetic head in the separating direction from the magneto-optical recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a magnetic head used in a magneto-optical recording / reproducing device such as a magnetic field modulation system.

[0002]

2. Description of the Related Art Generally, in a magnetic field modulation type magneto-optical recording / reproducing apparatus, the distance between a magnetic head and a magneto-optical recording medium is set to be extremely small in order to reduce recording loss and prevent unnecessary radiation. There is. Further, when the distance between the magnetic head and the magneto-optical recording medium changes, the strength of the magnetic field also changes, and the CN and the error rate deteriorate, or the magnetic head and the magneto-optical recording medium collide.

Therefore, a conventional magnetic head drive control device is provided with a distance sensor that outputs a signal corresponding to the distance between the magnetic head and the magneto-optical recording medium, and the magnetic head is detected according to the detection output of the distance sensor. A servo loop for driving the motor is configured.

Further, the drive control device for this magnetic head is
It is equipped with a changeover switch that turns the servo loop on and off. The changeover switch is turned on during recording to activate the servo.

With the above structure, the conventional drive control device for the magnetic head controls the distance between the magnetic head and the magneto-optical recording medium at the time of recording so as to be a constant minute distance.

[0006]

As described above, in the conventional magnetic head drive control device, the distance between the magnetic head and the magneto-optical recording medium is controlled so as to be a constant minute distance at the time of recording. ing.

Therefore, when the magnetic head is in the neutral position where it is not under any drive control and the position is sufficiently separated from the magneto-optical recording medium, when the servo loop is turned on, the magnetic head is magneto-optically recorded. A lot of power is consumed to get close enough to the medium. Further, when the neutral position is a position sufficiently close to the magneto-optical recording medium, the magneto-optical recording medium collides with the magnetic head when the magneto-optical recording medium is loaded or unloaded at the recording or reproducing position. have.

The present invention has been made in consideration of the above points. The power consumption in the position control of the magnetic head is reduced, and the magneto-optical recording medium serves as the magnetic head when loading or unloading the magneto-optical recording medium. An object of the present invention is to provide a drive control device for a magnetic head that prevents collision.

[0009]

SUMMARY OF THE INVENTION A magnetic head drive control device of the present invention is a magnetic head for controlling a distance between a magnetic head for magneto-optical recording and a magneto-optical recording medium to be constant when recording information. A drive controller, which is a switch 8 for switching on / off a servo loop of the drive controller for the magnetic head, and a drive signal for driving the magnetic head in a direction away from the magneto-optical recording medium. PWM generating circuit 6 as drive signal generating means for generating
And a control means for controlling to drive the magnetic head based on the drive signal by turning off the switch 8 when the magneto-optical recording medium is loaded in or unloaded from the recording or reproducing position. And the control circuit 5 as

[0010]

In the magnetic head drive control device having the above structure, when the magneto-optical recording medium is loaded or unloaded at the recording or reproducing position, the control circuit 5 controls the distance between the magnetic head and the magneto-optical recording medium to be constant. The servo loop switch 8 is turned off, and the magnetic head is controlled to be driven based on the drive signal for driving the magnetic head in the direction away from the magneto-optical recording medium.

Therefore, since the neutral position of the magnetic head can be set to a position close to the magneto-optical recording medium, the power consumption at the servo-on can be reduced. Also, if the magneto-optical recording medium is loaded at the recording or reproducing position,
It also prevents the magneto-optical recording medium from colliding with the magnetic head when unloaded from it.

[0012]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 2 shows the construction of an embodiment of a magneto-optical recording / reproducing apparatus using the magnetic head drive control apparatus of the present invention. In the figure, the spindle motor 11 rotates the magneto-optical recording medium 12 at a predetermined rotation speed. Magnetic head 16
Are arranged at a predetermined interval on the recording surface of the magneto-optical recording medium 12 and generate a magnetic field modulated according to a recording signal. The optical pickup 15 is arranged on the back surface of the magneto-optical recording medium 12 so as to face the magnetic head 16, and irradiates the magneto-optical recording medium 12 with laser light to raise the temperature of the recording surface to the Curie temperature.

The distance sensor 3 is provided on the magnetic head 16 and outputs a signal corresponding to the distance between the magnetic head 16 and the magneto-optical recording medium 12. The distance sensor 3 is specifically configured to detect the oscillation frequency, which is generated by the change in the electrostatic capacitance formed between the recording surface of the magneto-optical recording medium 12 and the distance sensor 3, by the PLL. The arm 13 fixes the magnetic head 16 and the optical pickup 15. The feeding mechanism 14 drives the arm 13 in the radial direction of the magneto-optical recording medium 12.

FIG. 3 shows an embodiment of the actuator 2 for driving the magnetic head 16. In the figure, the damper 22 is connected to the magnetic head 16 via the shaft 21.
Is elastically supported. The coil 23 is fixed to the shaft 21, and a current corresponding to the signal output from the distance sensor 3 flows through the coil 23 so as to be orthogonal to the magnetic flux of the magnet 24.

FIG. 1 is a block diagram showing a concrete structure of a drive controller for a magnetic head according to the present invention. In the figure,
The PWM generation circuit 6 outputs a pulse signal with a desired duty. The switch 8 is a servo loop switch,
The pulse signal output from the PWM generation circuit 6 is turned on by an H level signal and turned off by an L level signal.

The switch 7 selects whether to output the pulse signal from the PWM generation circuit 6 as a control signal for the switch 8 or to the drive circuit 1. The servo circuit 4 is composed of an amplifier and a phase compensation circuit. Control circuit 5 is P
The duty of the pulse signal output from the WM generating circuit 6 and the switching of the switch 7 are controlled.

Next, the operation will be described based on the above configuration.

First, when the magneto-optical recording medium 12 is loaded at the recording or reproducing position, the control switch 8 remains off, and the control circuit 5 switches the switch 7 to the on side. Further, the control circuit 5 outputs the control signal PW from the PWM generation circuit 6 so as to output a pulse signal of a predetermined duty.
It is sent to the M generation circuit 6. Upon receiving this, the PWM generation circuit 6 sends a pulse (PW) to the drive circuit via the switch 7.
M) Send out the signal. The drive circuit 1 converts this pulse signal into a signal for driving the actuator 2 and applies it to the actuator 2.

As a result, a current flows through the coil 23 of the actuator 2, so that the magnetic head 16 is driven in the direction away from the magneto-optical recording medium 12 against the damper 22 from the neutral position. The pulse signal is controlled, for example, so that the width of its H level gradually decreases. This allows
The magnetic head 16 can be gradually moved from the neutral position. This is continued until the loading on the recording or reproducing position of the magneto-optical recording medium 12 is completed.

When the magneto-optical recording medium 12 is loaded at the recording or reproducing position, the control circuit 5 is controlled so that the H level width of the pulse signal from the PWM generating circuit 6 gradually increases. Therefore, the magnetic head 16 gradually returns to the neutral position.

Next, when a command signal (REC signal) for recording information as shown in FIG. 4A is generated on the magneto-optical recording medium 12 loaded by means not shown, control is performed prior to the recording operation. The circuit 5 switches the switch 7 to the off side. Further, the control circuit 5 sends a control signal to the PWM generation circuit 6 so that the PWM generation circuit 6 outputs a pulse signal that changes so that the duty gradually increases as shown in FIG.

Therefore, since the pulse signal output from the PWM generation circuit 6 is applied to the switch 8 via the switch 7, the switch 8 is turned on at the H level of the pulse signal,
Turns off at L level. That is, the servo loop of the magnetic head 16 is turned on only while the pulse signal is at the H level, and the signal output from the distance sensor 3 is applied to the actuator 2 via the servo circuit 4, the switch 8 and the drive circuit 1, and the magnetic head Sixteen positions are controlled.

During the transition period from time t1 to time t2 when the magnetic head 16 moves from the neutral position (initial position) to the target position, the duty of the pulse signal is gradually increased to prevent overshoot near the target position. To prevent. After t2, the control circuit 5 controls the PWM generation circuit 6 so that the level of the pulse signal becomes H. Therefore, the switch 8 remains turned on from this point, and the position control of the magnetic head 16 is performed as before. ..

After that, the recording surface of the magneto-optical recording medium 12 is raised to the Curie temperature by the light beam emitted from the optical pickup 15. At this time, a magnetic field modulated according to the recording signal is generated from the magnetic head 16 to record the signal. As the recording is performed, the arm 13 is moved in the radial direction of the magneto-optical recording medium 12 by the feeding mechanism 14, so that the recording information is spirally recorded.

At t3, when the recording operation is completed, the control circuit 5 outputs a control signal to the PWM generation circuit 6 so that the PWM generation circuit 6 outputs a pulse signal whose duty gradually changes as shown in FIG. send.

Therefore, in the transition period from time t3 to time t4 when the magnetic head 16 returns from the target position to the neutral position (initial position), the duty of the pulse signal is gradually reduced to prevent overshoot near the initial position. To prevent. After t4, since the control circuit 5 controls the PWM generating circuit 6 so that the level of the pulse signal becomes L, the servo loop switch 8 remains off and the magnetic head 16 converges (stands) at the neutral position. ..

When the magneto-optical recording medium 12 is unloaded from the recording or reproducing position, the switch 8 remains off and the control circuit 5 turns the switch 7 on. Further, the control circuit 5 outputs the control signal PW from the PWM generation circuit 6 so as to output a pulse signal of a predetermined duty.
It is sent to the M generation circuit 6. Upon receiving this, the PWM generation circuit 6 sends a pulse (PW) to the drive circuit via the switch 7.
M) Send out the signal. The drive circuit 1 converts this pulse signal into a signal for driving the actuator 2 and applies it to the actuator 2.

As a result, a current flows through the coil 23 of the actuator 2, so that the magnetic head 16 is driven in the direction away from the magneto-optical recording medium 12 against the damper 22 from the neutral position. Since the width of the H level at this time is also controlled to be gradually reduced, the magnetic head 16 gradually moves to a predetermined position. This is the magneto-optical recording medium 12
Is continued from the recording or reproducing position until unloading is completed.

The position control of the magnetic head 16 is performed as described above.

[0031]

As described above, according to the magnetic head drive controller of the present invention, when the magneto-optical recording medium is loaded into or unloaded from the recording or reproducing position, the control means is the magnetic head. The switching means of the servo loop for controlling the distance to the magneto-optical recording medium constant is turned off, and the magnetic head is controlled to be driven based on the drive signal for driving the magnetic head in the direction away from the magneto-optical recording medium. As a result, the neutral position of the magnetic head can be set to a position close to the magneto-optical recording medium, so that the power consumption at the servo-on can be reduced. Further, when the magneto-optical recording medium is loaded or unloaded at the recording or reproducing position, the magneto-optical recording medium does not collide with the magnetic head.

[Brief description of drawings]

FIG. 1 is a block diagram showing a specific configuration of an embodiment of a magnetic head drive controller according to the present invention.

FIG. 2 is a side view showing the configuration of an embodiment of a magneto-optical recording / reproducing apparatus using the magnetic head drive control apparatus of the present invention.

FIG. 3 is a sectional view showing the configuration of an embodiment of an actuator of the magnetic head drive control device of the present invention.

FIG. 4 is a time chart for explaining the operation of the magnetic head drive controller according to the present invention.

[Explanation of symbols]

 1 Drive Circuit 2 Actuator 3 Distance Sensor 4 Servo Circuit 5 Control Circuit (Control Means) 6 PWM Generation Circuit (Drive Signal Generation Means) 7 Switch 8 Switch (Switching Means) 12 Magneto-Optical Recording Medium 16 Magnetic Head

Claims (2)

[Claims] 1. A drive control device for a magnetic head, which controls a distance between a magnetic head for magneto-optical recording and a magneto-optical recording medium to be constant when information is recorded. Servo loop on /
Switching means for turning off, drive signal generating means for generating a drive signal for driving the magnetic head in a direction away from the magneto-optical recording medium, and whether the magneto-optical recording medium is loaded at a recording or reproducing position. Or when unloaded from it,
And a control means for controlling the magnetic head to be driven based on the drive signal by turning off the switching means. 2. The drive control device for a magnetic head according to claim 1, wherein the drive signal is a PWM signal.