JPH05114192A - Magnetic head driving control method for optical magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To improve a C/N at the time of writing by permitting a writing by a magnetic head only when the deviation between the position of an optical spot by an optical head and the position of a magnetic spot by the magnetic head is within a specified range. CONSTITUTION:One surface of a disk 1 is used for writing and erasing information by a magnetic head 3 and the other surface is used for following an optical spot OS to a track arranged by an optical head 2. The heads 2 and 3 are connected with a connection section 6 and when a head traveling mechanism 40 is operated, the heads 2 and 3 are moved in the same direction and by the same quantity. the middle point of the detected optical spot OS, that is, when a tracking difference signal is 0, is detected by a position detection circuit 20 for detecting the position of the opticals spot OS. Then, when the tracking difference signal is within the range of a specified level from the position of the middle point, a writing enabling signal WE is outputted to a magnetic head driving circuit 30. Thus, even when eccentricity of the disk is large, the C/N at the time of writing is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head drive control system for writing and erasing information on a magneto-optical disk of a magneto-optical recording / reproducing apparatus, and more particularly to a C / N ratio (carrier / noise ratio). The present invention relates to a magnetic head drive control system for obtaining good writing pits.

[0002]

2. Description of the Related Art Conventionally, in a magneto-optical recording / reproducing apparatus using magnetic field modulation, which has both a magnetic head and an optical head,
A magnetic spot is formed at a predetermined position on the magneto-optical disk by a magnetic head, a magnetic field is applied in a predetermined direction, and an optical head concentrates laser light at the predetermined position to form a light spot. Information is written by heating the recording layer of the magneto-optical disk to form pits in which the magnetization is inverted at the light spots. Therefore, it is necessary to control the alignment between the magnetic spot of the magnetic head and the light spot of the optical head to match the magnetic spot and the light spot.

In such a magneto-optical recording / reproducing apparatus, a surface deviation due to eccentricity of the magneto-optical disk is detected as a focus error signal by the optical head, and the tracking actuator is operated based on the focus error signal. −
A method is well known in which the position of the light spot is made to follow the track groove by controlling the laser beam and making it follow the surface wobbling of the magneto-optical disk to move the objective lens of the optical head.

[0004]

However, the above conventional magnetic head drive control method has the following problems. That is, the track actuator provided in the optical head follows the disc eccentricity to control the light spot to an optimum position, but the eccentricity is ± 100 μm.
It reaches m. On the other hand, the magnetic spot by the magnetic head is only about 100 μm at the maximum, and as shown in FIG. 4, when the tracking actuator follows the eccentricity of the magneto-optical disk and approaches the end, Between the magnetic spot and the magnetic spot occurs, and as a result, the signal at the edge of the pit becomes unstable, and only a write pit with a poor C / N ratio can be obtained.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic head drive control system for a magneto-optical disk device which does not deteriorate the C / N ratio during writing.

[0006]

In order to solve the above-mentioned problems, the present invention provides a magnetic head for writing or erasing information on one surface of a magneto-optical disk, and the magneto-optical disk on the other surface of the magneto-optical disk. Of the magneto-optical recording / reproducing apparatus for forming a magnetic spot on the magneto-optical disk by arranging an optical head for causing the optical spot to follow the track and supplying a magnetic head drive current from the magnetic head drive means to the magnetic head. In the head drive control system,
Position detecting means for detecting the position of the light spot by the optical head is provided, and the position detecting means, when the detected position of the light spot is within a predetermined range from the neutral point, causes the magnetic head to drive the magnetic head. It is characterized by outputting a write permission signal for permitting the writing of information by.

[0007]

According to the present invention, the magnetic head drive control system of the magneto-optical recording / reproducing apparatus is constructed as described above, and only when the deviation between the position of the optical spot by the optical head and the position of the magnetic spot by the magnetic head is within a predetermined range. Since the writing of information by the magnetic head is permitted, the C / N at the time of writing information is improved even when the eccentricity of the magneto-optical disk is large.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a magneto-optical disk device to which the present invention is applied. In the figure, 1 is a disc, 2
Is an optical head, 3 is a magnetic head, 4 is a tracking actuator for driving the objective lens of the optical head 2, 5 is a feed motor, 10 is an optical head controller for controlling the position of the optical head 2, and 20 is optical. A position detection circuit for detecting the position of the light spot of the head 2, a magnetic head drive circuit 30 for generating a current for driving the magnetic head 3, and a head feed mechanism 40 for moving the head by the feed motor 5. .. Further, since the optical head 2 and the magnetic head 3 are connected by the connecting portion 6, when the head feeding mechanism 40 operates, the optical head 2 and the magnetic head 3 move in the same direction by the same amount.

FIG. 2 is a functional block diagram showing the optical head controller 10 of this embodiment and its peripheral circuits. The control of the optical head 2 of this embodiment will be described with reference to FIGS. In the magneto-optical disk device, it is necessary to accurately follow the optical spot OS of the optical head 2 to the center of the track of the disk 1 rotating at high speed.
As described above, the eccentricity amount of. ± .100 .mu.m can reach. +-. 100 .mu.m, so that a high-band servo system is required. Therefore, in the magneto-optical disk apparatus including this embodiment, the tracking actuator 4 that drives only the objective lens of the optical head 2 is usually used.
And a two-stage servo system using two driving means of the feed motor 5 for driving the entire head.

As shown in FIG. 2, disturbance such as eccentricity is input to one of the subtractors 10-1, and the output of the subtractor 10-1 is applied to the compensation circuit 10-2. The output of the compensation circuit 10-2 is sent to the tracking actuator 4 and the objective lens of the optical head 2 is driven. In addition, the compensation circuit 10-
The output of 2 is further sent through the compensating circuit 10-3.
And the feed motor 5 is driven. Therefore, the light spot OS of the optical head 2 is represented as an added value of the output of the tracking actuator 4 and the output of the feed motor 5. Then, a tracking error signal T representing the error between the position of the light spot OS and the center of the track of the disc 1
rE is fed back to the subtractor 10-1, and the difference value between the disturbance such as eccentricity and the tracking error signal Tr.E is again corrected by the compensation circuit 10-.
2 is applied. The tracking error signal is also output to the position detection circuit 20. Since the tracking error signal is well known, its detailed description is omitted.

Next, the operation of the position detection circuit 20 will be described. The tracking error signal changes as shown in FIG. 3 as the track deviation increases. The position detection circuit 20 detects the position of the neutral point, that is, when the tracking error signal is 0 (zero), and when the tracking error signal is within a predetermined level range from the position of the neutral point, the magnetic head is detected. The write enable signal WE is output to the drive circuit 30.

The magnetic head drive circuit 30 applies the magnetic head drive current to the magnetic head 3 only when the write enable signal WE is input. Therefore, when the deviation between the optical pit OS and the magnetic pit MS is within a predetermined range, information is written on the disc 1.

In this embodiment, the case where the optical pit OS and the magnetic pit MS are deviated due to the eccentricity of the disk 1 has been described, but the tracking actuator 4 is shaken laterally such as after a seek. It is obvious that the present invention can be applied to the case where

[0014]

As described above, according to the present invention, the following excellent effects can be obtained. Since the writing of information by the magnetic head is permitted only when the deviation between the position of the light spot OS and the position of the magnetic spot MS is within a predetermined range, even when the eccentricity of the disk is large, C / N is improved.

Even when the tracking actuator is laterally swaying, such as after a seek, it is possible to know the write permission timing by the write permission signal, and write information in an unstable state. There is nothing to do.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a magneto-optical disk device to which the present invention is applied.

FIG. 2 is a functional block diagram showing an optical head controller 10 and its peripheral circuits.

FIG. 3 is a diagram for explaining the operation of the position detection circuit 20.

FIG. 4 is a diagram illustrating a positional shift between a light spot and a magnetic spot.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 disk 2 optical head 3 magnetic head 4 tracking actuator 5 feed motor 6 connection part 10 optical head control part 20 position detection circuit 30 magnetic head drive circuit 40 head feed mechanism

Claims (1)

[Claims] 1. A magnetic head for writing or erasing information is arranged on one surface of the magneto-optical disk, and an optical head for making a light spot follow a track of the magneto-optical disk is arranged on the other surface of the magneto-optical disk. In a magnetic head drive control system of a magneto-optical recording / reproducing apparatus for forming a magnetic spot on the magneto-optical disk by supplying a magnetic head drive current to the magnetic head from a magnetic head drive means, Position detecting means for detecting the position of, the position detecting means, when the position of the detected light spot is within a predetermined range from the neutral point, information by the magnetic head to the magnetic head driving means. Drive of a magnetic head of a magneto-optical recording / reproducing apparatus characterized by outputting a write permission signal for permitting writing of data Your system.