JPH05282731A - Object lens control system - Google Patents

Abstract

PURPOSE:To secure the reproducibility of data at all times by detecting an error in the tracking of an object lens about an optical pickup device and giving an offset quantity prior to the recording of the data. CONSTITUTION:This control system supplies a test signal from a control system to an encoder decoder 46 prior to the magnetooptic recording to record the test signal and also detect the reproduction signal of the test signal recorded by a servo RF amplifier 40 at the same time. When the data are recorded, a servocontrol circuit 43 performs tracking control over the objective 2 by making a shift by the offset quantity stored in a memory 42. In this case, even when a position shift is caused during use, the reproducibility of the data is secured at all times in a range of the tracking fine adjustment of the object lens 2.

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 capable of erasing and rewriting information on a disk-shaped magneto-optical recording medium, and more particularly to a magnetic field modulation type overwritable magneto-optical recording medium. In the magneto-optical disk device,
The present invention relates to an objective lens control system that facilitates objective lens position control.

[0002]

2. Description of the Related Art Conventionally, a magneto-optical recording method based on a magnetic field modulation method has been attempted to shorten recording, reproducing and erasing times, and to sufficiently improve performance in order to increase the capacity and speed of access. .. Such a magneto-optical disk device has a structure as shown in FIG. 6, for example. That is, the seek motor uses the optical head (optical pickup device) 10
3 and the magnetic head 108 are simultaneously performing seek operation. The seek motor is composed of a linear motor coil 104 provided on the optical head 103, and a magnetic circuit including a magnet 106 and a yoke 105 provided along a guide 107 for guiding the optical head 103. The magnetic head 108 is attached to a flying slider, the slider is attached to a connecting member 110 via a support beam (suspension) 109, and the connecting member 110 is attached to the optical head 10.
It is fixed at 3.

The optical head 103 has its objective lens 1
An actuator 102 for two-dimensionally driving 02a is provided so that the objective lens 102a can be finely adjusted in the tracking direction and the focus direction. The seek operation in the radial direction of the magneto-optical recording medium 101 is performed by the linear motor coil 10 as described above.
4 is performed by current control, and tracking and focusing during recording and reproduction are performed by the actuator 102.
The current is controlled to the corresponding coil of. Objective lens 102 by the actuator 102 in this case
The tracking control of a is limited to the movable range of the objective lens 102a, and when the tracking error is large and exceeds the movable range, the seek motor is used to control the tracking of the optical head 103 itself. ..

[0004]

However, in the above-mentioned structure, the relative position between the optical head 103 and the magnetic head 108 is the data in the magneto-optical recording medium which is exchangeable with respect to the magneto-optical disk device. Since it affects the reproducibility of, it must be adjusted with high precision. Therefore, it is necessary to pay close attention when assembling the device, but the magnetic head 108 is used as a support beam (suspension).
Since it is mechanically coupled to the optical head side via 109, it is difficult to adjust it to the required accuracy, and a considerable amount of time is spent on this. Further, when the device is used, a change in temperature inside the device causes a change in volume of the mechanical coupling portion, which may cause displacement of the relative position between the optical head 103 and the magnetic head 108. As described above, when the accuracy of the relative position adjustment is lowered, the reproducibility of data may be lost even within the fine adjustment movable range of the objective lens 102a by the actuator 102.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in assembling the apparatus, the relative position adjustment between the magnetic head and the optical head is insufficient, and / or the temperature inside the apparatus changes. Even if the accuracy of the relative position adjustment deteriorates, the tracking error of the objective lens with respect to the optical pickup device is detected prior to the recording of the data so as not to perform the recording in which the reproducibility of the data is lost. SUMMARY OF THE INVENTION It is an object of the present invention to provide an objective lens control system adapted to give an offset amount during recording of an optical pickup device.

[0006]

Therefore, according to the present invention,
At least the magnetic head that irradiates the disc-shaped magneto-optical recording medium with a laser beam to form a light spot from the optical pickup device and that sled-moves integrally with the optical pickup device in the track direction of the magneto-optical recording medium In a magneto-optical disk device in which a bias magnetic field is applied corresponding to a small area of a light spot to write and read a magneto-optical signal, the optical pickup device drives an objective lens in a focus direction and a tracking direction. It is equipped with a two-dimensional actuator that records and reproduces a test signal prior to recording and reproducing, detects the center position of the movable range of the objective lens where the reproduced signal at that time is above a certain level, and The amount of offset from the initial position of the objective lens with respect to the pickup device is stored in memory. In stores, it is to correct the seek operation of the optical pickup apparatus in the offset amount at the time of recording the data.

[0007]

Embodiments of the present invention will be specifically described below with reference to the drawings. In the magneto-optical disk device shown here, an optical head (optical pickup device) 6 is used for the seek motor.
And a magnetic head (not shown) provided on the flying slider 4
And both are seeking at the same time. The seek motor is a linear motor coil 9 provided on the optical head 6, a magnet 10 provided along a guide rail 8 for guiding the optical head 6, a center yoke 12, a back yoke 11, and a relay connecting these. The magnetic circuit is composed of the yokes 13, 13. The slider 4 is attached to the rotating member 14 of the magnetic head retracting mechanism via a support beam (suspension) 5. The rotating member 14 is pivotally supported on the optical head 6 by a support shaft 15. A control roller 14a for retreat is attached to the rear end of the rotating member 14, and a drive member (not shown) of a retreat mechanism having a pressing surface extending in the seek direction is attached to this.
The control roller 14a is arranged so as to face the upper side so as to push down the control roller 14a.

The optical head 6 is provided with an objective lens 2 facing the magnetic head, and is equipped with an actuator 3 for finely adjusting the objective lens 2 in the tracking direction and the focus direction. The actuator 3 is shown in FIG.
As shown in detail in FIG.
The back yoke portions 26a, 26a facing each other are formed on the left and the right, the magnets 25, 25 are attached to the back yoke portions 26a, 26a, and the lens holder 21 holding the objective lens 2 is arranged between them. The magnet 25,
A tracking coil 24 and a focusing coil 23 are mounted opposite to 25. On one side of the yoke 26, a spacer 27 is arranged at the back surface of the back yoke portion 26a, and leaf springs 22, 22 are extended from the front and the rear of the lens holder 21. The lens holder 21 is supported so as to be movable back and forth (tracking direction). Therefore, when the coil 24 is energized, the lens holder 21 is finely adjusted and moved in the tracking direction.

Further, in this embodiment, one leaf spring 22 is provided.
A plate-shaped detection end member 22a is cut and raised, and the lens position sensor 28 is sandwiched by the left and right sides.
Is attached to the yoke 26 via a bracket. As shown in FIG. 3, the lens position sensor 28 includes LEDs that face each other with the detection end member 22a interposed therebetween.
31 and a phototransistor 32, which are connected to the power supply Vcc through resistors 33 and 34, respectively, and the output end (OUTPUT) thereof is connected to the arithmetic circuit 41 (see FIG. 5). The characteristics of the phototransistor are
As shown in FIG. 4, the position of the edge of the detection end member 22a is Lm with respect to the center of the lens position sensor.
The ratio of the photocurrent value when the distance is m is specified.
Therefore, the photocurrent value changes due to the fine adjustment movement of the objective lens 2 (in other words, the lens holder 21).

Further, the control system of this magneto-optical disk device has a structure conceptually shown in FIG. Here, control is performed mainly by the system controller 44, and the spindle motor 35 is driven via the servo control circuit 43 by a command from the system controller 44 to rotate the magneto-optical recording medium 1 and , The energizing signal to the focus drive circuit 36
To the coil 23, the tracking drive circuit 37 to the coil 24, and the linear motor drive circuit 38 to the linear motor coil 9.
Each can be output. On the other hand, with respect to the optical system, the laser driver 39 is activated by the command signal from the system controller 44. In the optical system, the servo / reflective light is reflected from the reflected light from the magneto-optical recording medium 1.
The servo signal and the data signal are taken out through the RF amplifier 40, the servo signal is fed back to the servo control circuit 38, and the energizing signal is controlled.
The data signal is output to the encoder / decoder 46 as a reproduction signal or a verify signal at the time of recording. The system controller 44 irradiates the recording surface of the magneto-optical recording medium with laser light in the optical system based on the data information introduced from the outside through the encoder / decoder 46, and the encoder / decoder 46 causes the magnetic head to radiate. Based on the data signal supplied to the drive circuit 45, a modulating magnetic field is applied to the magnetic head to realize magneto-optical recording.

In particular, in the present invention, prior to recording on the magneto-optical recording medium 1, a test signal is applied from the control system to the encoder / decoder 46 to record the test signal and simultaneously record it by the servo RF amplifier 40. The reproduced signal of the test signal is detected.

When recording the test signal, the system controller 44 performs the recording while driving the objective lens 2 from one end to the other end of the movable range via the servo control circuit 43.

The servo control circuit 43 discriminates the amplitude level of the detected reproduction signal and controls the arithmetic circuit 41 so that the movable range of the objective lens 2 in which the amplitude level becomes a certain level or more (the applied magnetic field required for recording). Is calculated based on the output of the position sensor 28, and the deviation amount (offset amount) between the center position and the reference position (initial position) of the objective lens 2 with respect to the optical head 6 is calculated. Is calculated and stored in the memory (storage means) 42.

When recording data,
The servo control circuit 43 performs tracking control of the objective lens 2 by shifting it by the offset amount stored in the memory 42.

Even if the tracking control of the objective lens 2 is not shifted by the offset amount, the optical head 6 follows the eccentricity of the track of the magneto-optical recording medium 1 (the objective lens 2 is located at the reference position of the optical head 6). The same effect can be obtained by performing the control for driving the optical head using the seek motor as described above by shifting by the offset amount stored in the memory 42. The shift is performed so as to compensate the offset amount.

In this way, if magneto-optical recording is performed on the magneto-optical recording medium 1 which is interchangeable with respect to the magneto-optical disk device, the relative positioning between the magnetic head and the optical head will be insufficient during assembly. Accuracy and / or
Even if a position shift occurs during use, reproducibility of data is always ensured within the range of the tracking fine adjustment of the objective lens 2 during recording.

[0017]

As described in detail above, according to the present invention, the optical pickup device is provided with the two-dimensional actuator for driving the objective lens in the focusing direction and the tracking direction. Recording / reproduction is performed, the center position of the movable range of the objective lens where the reproduction signal at that time exceeds a certain level is detected, and the offset amount between this and the initial position of the objective lens with respect to the optical pickup device is stored in the storage means. However, since the seek operation amount of the optical pickup device is corrected by the offset amount at the time of data recording, the relative position adjustment between the magnetic head and the optical head is insufficient at the time of assembling the device, and / or the temperature inside the device. Even if the accuracy of the relative position adjustment deteriorates due to changes, etc., it is possible to access the optical pickup device during data recording. The objective lens Te, the can bring the center of the fine adjustment range, it is inevitable that the reproducibility of the data in substantially the fine adjustment range is lost, there is an effect that can be played, the verification accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is likewise an enlarged perspective view of a main part.

FIG. 3 is a circuit configuration diagram of a sensor portion.

FIG. 4 is a graph showing a characteristic curve of a sensor.

FIG. 5 is a block diagram showing a control system of the present invention.

FIG. 6 is a perspective view of a conventional example.

[Explanation of symbols]

 1 Magneto-optical recording medium 2 Objective lens 3 Actuator 4 Slider 6 Optical head 28 Position sensor 41 Arithmetic circuit 42 Memory 43 Servo control circuit 44 System controller

Claims (1)

[Claims] 1. A disk-shaped magneto-optical recording medium is irradiated with laser light from an optical pickup device to form a light spot, and a thread is moved integrally with the optical pickup device in the track direction of the magneto-optical recording medium. In a magneto-optical disk device in which a bias magnetic field is applied from the magnetic head at least corresponding to the minute area of the light spot to write and read a magneto-optical signal,
The optical pickup device is equipped with a two-dimensional actuator that drives the objective lens in the focus direction and the tracking direction, and the test signal is recorded / reproduced prior to recording / reproduction, and the reproduction signal at that time is above a certain level. The center position of the movable range of the objective lens is detected, and the offset amount between this and the initial position of the objective lens with respect to the optical pickup device is stored in the storage means, and the seek of the optical pickup device is performed with the offset amount when recording data. An objective lens control system characterized by correcting a movement amount.