JP2970787B2 - Objective lens control system - Google Patents

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. Magneto-optical disk drive
The present invention relates to an objective lens control system that facilitates objective lens position control.

[0002]

2. Description of the Related Art Heretofore, a magneto-optical recording system using a magnetic field modulation system has been intended to shorten recording, reproducing, and erasing times, to achieve a large capacity and a high-speed access, and to sufficiently improve the performance. . Such a magneto-optical disk device has, for example, a configuration as shown in FIG. That is, the optical head (optical pickup device) 10 is driven by a seek motor.
3 and the magnetic head 108 are simultaneously seeking. The seek motor includes a magnetic circuit including a linear motor coil 104 provided on the optical head 103 and 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 floating slider, and the slider is attached to a connecting member 110 via a support beam (suspension) 109. The connecting member 110 is attached to the optical head 10
It is fixed to 3.

The optical head 103 has an objective lens 1
An actuator 102 for two-dimensionally driving the objective lens 102a is provided, and fine adjustment of the tracking direction and the focus direction of the objective lens 102a can be performed. As described above, the seek operation of the magneto-optical recording medium 101 in the radial direction is performed by the linear motor coil 10.
4 and the tracking and focusing during recording and reproduction are performed by the actuator 102.
Of the corresponding coils. The 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. If the tracking error is large and exceeds the movable range, the tracking control of the optical head 103 itself is performed by using the seek motor. .

[0004]

However, in the above configuration, the relative position between the optical head 103 and the magnetic head 108 is determined by the data position on the magneto-optical recording medium which is interchangeable with respect to the magneto-optical disk device. It must be adjusted with high precision because it affects the reproducibility. Therefore, when assembling the apparatus, it is necessary to pay close attention.
Due to the mechanical coupling to the optical head side via 109, it is difficult to adjust to the required accuracy, and considerable time is required. Further, when the apparatus is used, a volume change occurs in the mechanical coupling portion due to a temperature change in the apparatus, which may cause a relative position shift between the optical head 103 and the magnetic head 108. As described above, when the accuracy of the relative position adjustment is reduced, 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 on the basis of the above circumstances, and the relative position between a magnetic head and an optical head is not sufficiently adjusted when assembling a device. Prior to data recording, a tracking error of the objective lens with respect to the optical pickup device is detected before the data is recorded so that even if the accuracy of the relative position adjustment is reduced, the recording is performed so that the reproducibility of the data is lost. It is an object of the present invention to provide an objective lens control system which gives an offset amount at the time of recording by an optical pickup device.

[0006]

Therefore, in the present invention,
The optical pickup device irradiates the disk-shaped magneto-optical recording medium with laser light to form a light spot, and at least the magnetic head that sled moves integrally with the optical pickup device in the track direction of the magneto-optical recording medium. In a magneto-optical disk drive in which a bias magnetic field is applied corresponding to a minute area of a light spot to perform writing and reading of a magneto-optical signal, the optical pickup device drives an objective lens in a focus direction and a tracking direction. A recording / reproduction of a test signal prior to recording / reproduction, and detecting a center position of a movable range of the objective lens in which a reproduction signal at that time is equal to or higher than a certain level. Store the amount of offset of the objective lens from the initial position with respect to the pickup device. 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]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 a seek motor.
And a magnetic head (not shown) provided on the flying slider 4
And seek operation at the same time. The seek motor includes 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. It is composed of a magnetic circuit composed of the yokes 13, 13. The slider 4 is attached to a rotating member 14 of a 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 retracting control roller 14a is mounted on the rear end of the rotating member 14, and includes a retracting mechanism driving body (not shown) having a pressing surface extending in the seek direction.
The control roller 14a is arranged so as to oppose the upper side so as to push down the control roller 14a.

The optical head 6 is provided with an objective lens 2 opposed to the magnetic head, and is equipped with an actuator 3 for finely adjusting the objective lens 2 in a tracking direction and a focusing direction. The actuator 3 shown in FIG.
As shown in detail in FIG.
A left and right facing back yoke portions 26a, 26a are formed, magnets 25, 25 are mounted on the back yoke portions 26a, 26a, and a lens holder 21 holding the objective lens 2 is disposed therebetween. The magnet 25,
A tracking coil 24 and a focusing coil 23 are attached to face 25. On one side of the yoke 26, a spacer 27 is disposed at the back of the back yoke portion 26a, from which leaf springs 22, 22 extend in front of and behind the lens holder 21. The lens holder 21 is supported so as to be able to move back and forth (tracking direction). Therefore, when the coil 24 is energized, the lens holder 21 is finely moved in the tracking direction.

In this embodiment, one leaf spring 22 is used.
A plate-shaped detection end member 22a is cut and raised, and the detection end member 22a is sandwiched from the left and right, so that a lens position sensor 28a is formed.
Are attached to the yoke 26 via a bracket. As shown in FIG. 3, the lens position sensor 28 includes an LED that faces the detection end member 22a.
31 and a phototransistor 32, which are connected to a power supply Vcc via resistors 33 and 34, respectively, and whose output terminal (OUTPUT) is connected to an arithmetic circuit 41 (see FIG. 5). The characteristics of the phototransistor are as follows.
As shown in FIG. 4, the position of the edge of the detection end member 22a with respect to the center of the lens position sensor is Lm.
The ratio of the photocurrent value at a distance of 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).

The control system of the magneto-optical disk drive has a configuration as conceptually shown in FIG. Here, the control is performed mainly by the system controller 44, and the spindle motor 35 is driven by the command from the system controller 44 via the servo control circuit 43 to rotate the magneto-optical recording medium 1 and , The energizing signal to the focus driving circuit 36
To the coil 23 via a tracking drive circuit 37, and to the linear motor coil 9 via a linear motor drive circuit 38,
Each can be output. On the other hand, for the optical system, the laser driver 39 is energized by a command signal from the system controller 44. In the optical system, the servo /
The servo signal and the data signal are taken out via 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 as a verify signal at the time of recording. The system controller 44 irradiates a laser on the recording surface of the magneto-optical recording medium with an optical system on the basis of data information introduced from the outside via the encoder / decoder 46. Based on the data signal supplied to the drive circuit 45, a modulation magnetic field is applied to a 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 supplied from the control system to the encoder / decoder 46, and the test signal is recorded and simultaneously recorded by the servo RF amplifier 40. The reproduced signal of the test signal is detected.

When the test signal is recorded, 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 determines the amplitude level of the detected reproduced signal and controls the arithmetic circuit 41 to control the movable range of the objective lens 2 where the amplitude level is equal to or higher than a predetermined value (the applied magnetic field required for recording). Is calculated based on the output of the position sensor 28, and a deviation amount (offset amount) between the center position and a 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 shifts the tracking control of the objective lens 2 by the offset amount stored in the memory 42.

Further, 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 shifting the control of driving the optical head using the seek motor as described above) by the offset amount stored in the memory 42. The shift is performed so as to compensate for the offset amount.

If magneto-optical recording is performed on the magneto-optical recording medium 1 which is interchangeable with the magneto-optical disk device in this manner, even if the relative positioning between the magnetic head and the optical head is insufficient during assembly, for example. Accuracy and / or
Even if a displacement occurs during use, reproducibility of data is always ensured within the range of the fine tracking adjustment of the objective lens 2 during recording.

[0017]

According to the present invention, as described in detail above, the optical pickup device is provided with a two-dimensional actuator for driving the objective lens in the focus direction and the tracking direction. Recording / reproduction is performed, and the center position of the movable range of the objective lens at which the reproduction signal at that time is equal to or higher than 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 recording data, the relative position adjustment between the magnetic head and the optical head is insufficient at the time of assembling the device, and / or Even if the accuracy of the relative position adjustment is reduced due to a change, etc., it is not possible to access the optical pickup device when recording data. 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 the drawings]

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

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

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

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]

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

Claims (1)

(57) [Claims] 1. An optical pickup device irradiates a laser beam to a disk-shaped magneto-optical recording medium to form a light spot, and sled moves integrally with the optical pickup device in a track direction of the magneto-optical recording medium. In a magneto-optical disk drive configured to apply a bias magnetic field from a magnetic head to at least a minute area of the light spot and perform writing and reading of a magneto-optical signal,
The optical pickup device includes a two-dimensional actuator that drives an objective lens in a focus direction and a tracking direction, performs recording / reproduction of a test signal prior to recording / reproduction, and sets a reproduction signal at that time to a certain level or more. The center position of the movable range of the objective lens is detected, and the offset amount between the center position of the objective lens and the initial position of the objective lens with respect to the optical pickup device is stored in the storage means. When data is recorded, the seek of the optical pickup device is performed using the offset amount. An objective lens control system for correcting an operation amount.