JPH05282732A - Object lens control system - Google Patents

Abstract

PURPOSE:To accurately perform reproducing and verification by recording and reproducing a test signal prior to recording and reproducing, and detecting a movable range of an object lens by which the reproduced signal reaches a constant level or more. CONSTITUTION:A servo control circuit 43 discriminates an amplitude level of reproduced signal detected, while controls an arithmetic circuit 41, calculates a movable range of an object lens 2 by which an amplitude level reaches a constant level or more based on an output of a position sensor 28, and stores it in memory (memory means) 42. And, when data is recorded, the servo control circuit 43 restricts tracking control so that tracking control of the object lens 2 is performed within the movable range stored in the memory 42. Therefore, reproducibility of data in reproducing is secured by performing magneto-optical recording to a magneto-optical recording medium 1 which is commutative with a magneto-optical disk device even if relative positioning between a magnetic head and an optical head in assembling is insufficient.

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. An objective lens control system that limits the fine adjustment range of the objective lens at the time of recording data is provided so as not to perform recording that will cause loss of data reproducibility even if the accuracy of relative position adjustment decreases. It is the one we are trying to provide.

[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. The recording / reproducing of the test signal is performed prior to the recording / reproducing, the movable range of the objective lens in which the reproduced signal at that time becomes a certain level or more is detected, and this is stored in the storage means. ,
The objective lens is driven only in the movable range when recording 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 drives the objective lens 2 from one end to the other end of the movable range via the servo control circuit 43 to perform the recording.

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 stored in the memory (storage means) 42. When recording data, the servo control circuit 43 causes the objective lens 2
The tracking control is restricted so that the tracking control is performed within the movable range stored in the memory 42.

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, the tracking fine adjustment range of the objective lens 2 during recording is limited, and reproducibility of data during reproduction is ensured.

It should be noted that the near seek performance can be improved by canceling the above-mentioned restrictions during data reproduction and finely adjusting the objective lens within a wider range than that during recording, which is allowed by the actuator 3.

[0016]

As described in detail above, the present invention irradiates a disk-shaped magneto-optical recording medium with laser light from an optical pickup device to form a light spot, and at the same time, in the track direction of the magneto-optical recording medium. In a magneto-optical disk device, a bias magnetic field is applied from a magnetic head that sled-moves integrally with the optical pickup device at least corresponding to a minute region 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 records / reproduces a test signal before recording / reproducing.
The movable range of the objective lens in which the reproduction signal at that time becomes a certain level or higher is detected, this is stored in the storage means, and the objective lens is driven only in the movable range at the time of data recording. At this time, the relative position adjustment between the magnetic head and the optical head is insufficient, or
Further, even when the accuracy of the relative position adjustment is deteriorated due to a change in the temperature inside the device, the fine adjustment range of the objective lens is limited when recording the data, so that the recording that does not lose the reproducibility of the data is not performed. There is an effect that reproduction, verification can be accurately performed.

[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 of a sensor characteristic curve.

FIG. 5 is a block diagram of 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 above optical pickup device is equipped with a two-dimensional actuator that drives the objective lens in the focus direction and the tracking direction. Recording / reproduction of a test signal is performed prior to recording / reproduction, and the reproduction signal at that time is above a certain level. The objective lens control system is characterized in that the movable range of the objective lens is detected, stored in a storage means, and the objective lens is driven only in the movable range when data is recorded.