JPH06338071A - Magneto-optical disk drive device - Google Patents

Abstract

PURPOSE:To detect the position of a galvanomirror without fitting the galvanomirror with an external sensor. CONSTITUTION:A photodetecting element 30 for detecting return light F5 of a light beam F1 irradiating a magneto-optical disk 13 is provided with four photodetecting parts A, B, C and D, which are equivalently quadripartite in the tracking direction and in the parallel direction to the direction of a data track, and the position of the galvanomirror performing fine tracking is detected by discriminating a change of the light receiving state of the return light F5 on these four photodetecting parts A, B, C and D.

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 drive device for recording (writing) and reproducing (reading) a magneto-optical disk with an optical pickup having an objective lens and a magnetic field modulation head, and more particularly to detecting the position of a galvano mirror. It is about.

[0002]

2. Description of the Related Art Conventionally, magneto-optical disk drive devices shown in FIGS. 12 to 15 have been developed as optimum magneto-optical disk drive devices for recording (writing) and reproducing (reading) data in a computer or the like.

In this case, a hermetically sealed case 1 formed in a box shape having a substantially rectangular parallelepiped shape has a case upper lid 4 fixed by a plurality of screws 5 to a top of a case main body 2 which also serves as a chassis when the top is opened via a gasket 3. The inside is completely sealed.

Next, a frame 6 for attachment to electronic equipment is horizontally attached to the lower portion of the hermetically sealed case 1 via a plurality of insulators 7 made of rubber or the like, and a print having a connector 8a on the attachment frame 6 is provided. The board 8 is mounted horizontally.

Next, the vertical spindle motor 10 is mounted on the case body 2 in the sealed case 1, and the magneto-optical disk 13 is mounted on the rotor 12 fixed to the upper end of the rotary shaft 11 of the spindle motor 10. The disk fixing member 14 is horizontally fixed by magnet chucking, screws, or the like. And this magneto-optical disk 1
The recording surface side 13a of No. 3 is arranged downward, and the non-recording surface side 1
3b is arranged upward.

Next, an optical pickup 16 is arranged below the magneto-optical disk 13 on the front end side (lower side in FIG. 12) of the spindle motor 10 in the sealed case 1.

The optical pickup 16 has a carriage 19 which is moved in a direction of an arrow a which is a radial direction of the magneto-optical disk 13 by a plurality of rollers (bearings) 18 between a pair of left and right parallel guide shafts 17, An arrow b, which is a focus direction with respect to the recording surface side 13a of the magneto-optical disk 13, is provided by a focusing motor 20 which is a uniaxial device including a leaf spring, a coil, a magnet (none of which are shown), etc. parallel to the carriage 19. The objective lens 21 mounted movably in the direction, and the carriage 1.
The non-recording surface side 12 b of the magneto-optical disk 13 is supported on the upper surface side of the magneto-optical disk 9 via a suspension 22 composed of a leaf spring.
A magnetic field modulation head 23 of a flying head type (a method of levitating by an airflow when the magneto-optical disk 13 rotates) disposed directly above the objective lens 21, a coil 24 attached to the carriage 19, and a pair of left and right sides. It has a linear voice coil motor 27, which is a moving mechanism composed of a pair of left and right inner and outer yokes 26 to which a magnet 25 is attached, and an optical system 28 for emitting and receiving a light beam with respect to the objective lens 21.

A pair of left and right inner and outer yokes 26 of the linear voice coil motor 27 are horizontally mounted on the case body 2, and a pair of left and right guide shafts 17 are horizontally arranged in parallel on the inner facing surfaces of these inner and outer yokes 26. It is installed.

The optical system 28 includes a light emitting element 29 such as a laser diode mounted on the case body 2, a light detecting element 30 such as a photodetector, and a collimator lens 3.
1. A horizontal optical system fixing portion 28a including a multi-lens 35, a beam splitter 32, a fine tracking galvano mirror 33, and the like, and the focusing motor 2
It is composed of a 45-degree reflecting mirror 34 arranged directly below the objective lens 21 of the movable part of the optical system which is 0.

In this magneto-optical disk drive device, the magneto-optical disk 13 is driven by the spindle motor 10.
Is rotationally driven at a high speed, and the magnetic field modulation head 23 is levitated on the non-recording surface 13b which is the upper surface of the magneto-optical disk 13 in the order of microns by the air flow generated at that time.

In the optical pickup 16, the light beam F ₁ which is a laser beam of parallel rays emitted from the light emitting element 29 in the optical system fixing portion 28a of the optical system 28 is passed through the collimator lens 31 and the beam splitter 32 to the galvano mirror 33. The light beam F ₂ which is horizontally emitted to the mirror and reflected at 90 ° in the same horizontal plane by the galvano mirror 33 is emitted to the 45-degree reflecting mirror 34, and is upwardly moved to 90 degrees by the 45-degree reflecting mirror 34.
° a light beam F ₃ reflected the emitted from below the objective lens 21, the beam spot F ₄ on the recording surface 13a of the magneto-optical disc 13 by focusing a light beam F ₃ on the beam spot F ₄ by the objective lens 21 Irradiate.

The recording surface side 1 of the magneto-optical disk 13
The reflected light, which is the return light from 3a, is converted into parallel rays by the objective lens 21, and the 45 degree reflecting mirror 34 and the galvano mirror 3
3, the beam splitter 32, the multi-lens 35 and the like are used to focus the light on the photodetector 30.

Then, the magnetic field modulation head 23 modulates and demodulates the vertical magnetic field of the magneto-optical disk 13, and
Recording (data writing) and reproduction (data reading) of the magneto-optical disk 13 can be performed by the light emitting operation of the light beam from the light emitting element 29 and the light receiving operation of the reflected light by the light detecting element 30.

At this time, the optical pickup 16 focuses the beam spot F ₄ of the objective lens 21 on the recording surface side 13a of the magneto-optical disk 13 in the direction of arrow b by controlling the energization of the coil in the focusing motor 20 to obtain the beam spot. Fine tracking (fine adjustment) of F _{4 in} the direction of arrow a is performed by controlling the angle of the galvanometer mirror 33 in the direction of arrow c.

When the deflection angle of the galvanometer mirror 33 exceeds the reference value, the energization of the coil 24 of the voice coil motor 27 is controlled so that the objective lens 21 and the magnetic field modulation head 23 with respect to the magneto-optical disk 13 move in the direction of arrow a. Performed by seeking (coarse movement).

That is, by energizing the coil 24, the carriage 19 is moved in the direction of arrow a between the two parallel guide shafts 17, and the objective lens 21 and the magnetic field modulation head 23 are moved by the carriage 19 to the magneto-optical disk 13. It is moved in the direction of arrow a, which is the radial direction.

[0017]

As described above, in the case where the fine tracking is performed by the angle control of the galvano mirror 33, the weight of the carriage 19 is lighter than that in the case where the fine tracking is performed by the biaxial device attached to the carriage 19. As a result, the tracking access time can be shortened and the voice coil motor 2 can be used.
7. It is possible to reduce the size, weight and power consumption.

However, in order to effectively perform fine tracking within a range in which the maximum deflection angle of the galvanometer mirror 33 does not exceed the reference value, it is necessary to always know the position of the galvanometer mirror 33, and the galvanometer mirror 33 is used by some method. It is necessary to detect the position of the mirror 33.

At this time, the simplest method is to attach an external sensor for detecting the position to the galvanometer mirror 33. However, if the external sensor is attached, the number of parts and the number of assembling steps increase, resulting in a significant cost increase. Further, if an external sensor is attached to the galvanometer mirror 33, the balance of the galvanometer mirror 33 is lost and the galvanometer mirror 33 becomes vulnerable to vibration and impact. If a counterweight or the like is attached for balancing, the weight (inertial force) of the galvano mirror 33 becomes heavy, and the galvano mirror 33
There is a problem in that the behavior of the angle control becomes worse and the servo characteristics are deteriorated.

The present invention has been made to solve the above problems, and provides a magneto-optical disk drive device capable of detecting the position of a galvanometer mirror without attaching an external sensor to the galvanometer mirror. Is intended.

[0021]

SUMMARY OF THE INVENTION To achieve the above object, a magneto-optical disk drive device of the present invention comprises a magneto-optical disk which is rotationally driven by a spindle motor, and an objective for recording and reproducing the magneto-optical disk. A lens and a magnetic field modulation head, a light emitting element that emits a light beam to the magneto-optical disk through the objective lens, a photo-detecting element that detects return light reflected by the magneto-optical disk and returned through the objective lens, and the objective lens. An optical system equipped with a galvano mirror for fine tracking for controlling the incident angle of a light beam on the linear beam, and a linear voice coil motor for moving at least the carriage to which the objective lens is attached in a substantially radial direction of the magneto-optical disk. In a magneto-optical disk drive device equipped with an optical pickup And at least two photo-detecting portions formed on the photo-detecting element, which are equivalently divided into at least two in a direction parallel to the tracking direction to receive the return light from the objective lens straddling, The position detection information of the galvano mirror is output to the control circuit according to the change in the light receiving state of the return light in the light detection unit.

[0022]

The magneto-optical disk drive device of the present invention configured as described above is originally provided with a photo-detecting element for detecting return light from the magneto-optical disk of an optical pickup and reproducing (reading) data. Since the position of the galvanometer mirror that performs fine tracking can be detected,
There is no need to attach an external sensor for position detection to the galvano mirror itself.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magneto-optical disk drive device to which the present invention is applied will be described below with reference to FIGS. It should be noted that the same structural parts as those in FIGS. 12 to 14 are designated by the same reference numerals to omit redundant description.

First, as shown in FIGS. 10 and 11, the pair of left and right leaf springs 36 fixed to the rear surface of the galvanometer mirror 33 are arranged on the pair of left and right positioning pins 3 of the mirror support member 37.
7a and a pair of left and right mounting plates 38 are used to insert a plurality of screws 3
It is attached to the mirror support member 37 by screwing with 9 or adhesion. And this galvano mirror 33
Is attached to the mirror support member 37 rotatably in the direction of arrow c about a pair of left and right horizontal rotation fulcrums 36a, which are narrow arm portions of the pair of left and right leaf springs 36.

The mirror support member 37 is attached to the mirror mount 40 fixed on the case body 2 and the three adjusting screws 4 are provided.
It is attached by 0. The mirror support member 37 is provided with the recess 37b on the back surface thereof so that the mirror mount 4 is
It is fitted to the horizontal adjustment shaft 40 of 0, and the mounting posture of the mirror support member 37 with respect to the mirror mount 40 can be adjusted in the direction of arrow d around the horizontal rotation fulcrum 42 by adjusting the three adjusting screws 41. Is configured.

A pair of upper and lower coils 43 fixed to the rear surface of the galvano mirror 33, a pair of upper and lower magnets 44 and a mirror fixed to the mirror supporting member 37 are provided between the galvano mirror 33 and the mirror supporting member 37. A galvanometer mirror motor 45 including a yoke formed of the support member 37 is formed. The galvano mirror 33 is configured so that the galvano mirror 33 can be angularly controlled in the direction of arrow c around the pair of left and right rotation fulcrums 36a by controlling the energization of the pair of upper and lower coils 43 of the galvano mirror motor 45.

Next, as shown in FIG. 9, the optical system fixing portion 28a of the optical system 28 includes a light emitting element 29 such as a laser diode.
And the beam splitter 32 between the collimator lens 31
Is arranged, and the Wollaston prism 35 is provided between the photodetector 30 such as a photodetector and the beam splitter 32.
a, the multi-lens 35, the cylindrical lens 35b, and the like are arranged on the same optical axis.

Then, the light beam F ₁ which is the laser light emitted from the light emitting element 29 is converted into parallel rays by the collimator lens 31 and emitted to the galvano mirror 33 through the beam splitter 32.
The 0 ° light beam F ₂ reflected the emitted 45 ° reflector 34, it emits a light beam F ₃ to the objective lens 21 and reflected by the 45 degree reflection mirror 34 to 90 °, converged by the objective lens 21 The beam spot F ₄ is irradiated on the recording surface side 13a of the magneto-optical disk 13 to record data on the magneto-optical disk 13.

On the other hand, the recording surface side 13 of the magneto-optical disk 13
The return light F ₅ reflected by a and returned to the beam splitter 32 through the objective lens 21, the 45-degree reflecting mirror 34, and the galvano mirror 33 becomes a parallel light beam through the Wollaston prism 35a, the multi-lens 35, and the cylindrical lens 35b to detect the light. The light is received by the element 30, and the data of the magneto-optical disk 13 is reproduced.

Then, the objective lens 21 is controlled to move in the direction of arrow b by controlling the energization of the coil of the focusing motor 20 to focus the beam spot F _{4 in} the direction of arrow b.

Further, fine tracking in the direction of the arrow a of the beam spot F ₄ is performed by controlling the angle of the galvano mirror 33 in the direction of the arrow c.

That is, as shown in FIG. 7, when the galvano mirror 33 is angularly controlled (finely adjusted) by the angle θ in the direction of arrow c, the light beam of the beam spot F ₄ on the magneto-optical disk 13 is shifted by the pupil shift of the objective lens 21. The axis moves in the direction of arrow a by a distance L ₁ .

Therefore, by utilizing this, the beam spot F ₄ is formed on the magneto-optical disk 13 as shown in FIG.
Fine tracking (fine adjustment) can be performed in the direction of arrow a along the tracking direction Y ₁ which is a direction perpendicular to the track direction X ₁ which is the length direction of the data track (signal bit string) TR of The beam spot F ₄ can be made to follow a minute position change of the data track TR in the radial direction of the disk 13.

At this time, as shown in FIG. 7, the magneto-optical disk 1 is controlled by controlling the angle of the galvano mirror 33 in the direction of arrow c.
The movement of the beam spot F _{4 on} the optical axis 3 by the distance L ₁ is represented as a shift of the distance L ₂ of the optical axis of the return light F ₅ received by the photodetection element 30 in the arrow a ′ direction.

That is, as shown in FIG. 8A, the beam spot F _{4 is} controlled by controlling the angle of the galvanometer mirror 33.
When fine tracking is performed in the direction of the arrow a along the tracking direction Y ₁ , the optical axis of the return light F ₅ received on the photodetector 30 is equivalent to the tracking direction Y as shown in FIG. 8B. It is moved in the direction of arrow a ′ along the direction Y ₂ parallel to ₁ . The arrow X ₂ direction shown in FIG. 8B is equivalently parallel to the data track direction X ₁ .

Therefore, the magneto-optical disk drive apparatus of the present invention detects the amount of movement of this return light F _{5 in} the direction of arrow a ′ by using the photodetector element 30 to detect the galvano mirror 33 in the direction of arrow c. The position is detected, and the fine tracking is performed so that the maximum deflection angle of the galvano mirror 33 in the direction of arrow c does not exceed the reference value.

When the maximum deflection angle of the galvano mirror 33 in the direction of arrow c exceeds the reference value, the voice coil motor 27 controls the entire carriage 19 to seek in the direction of arrow a.

Next, the position detecting device for the galvano mirror 33 of the present invention will be described with reference to FIGS.

First, FIG. 6 shows a concentric circular data track TR of the magneto-optical disk 13. About 70 or more non-signal portions BS are formed in one circumference of the data track TR which is a signal pit row. Therefore, these signalless portions BS can totally reflect the beam spot F ₄ . In addition, a pair of sample pits SP for sample servo are formed on both sides of the center line O ₁ of the data track TR in these signalless portions BS. The arrow e direction indicates the rotation direction of the magneto-optical disk 13.

Then, the beam spot F _{4 is set} to the non-signal portion B.
The beam spot F ₄ is finely tracked between the pair of sample pits SP in the direction of arrow a shown in FIG. And the non-signal part B
The return light F ₅ totally reflected at S is received by the four-divided photodetector sections A, B, C, and D of the photodetector 30 shown in FIGS. 3 to 5, and the light receiving state changes at that time. , A focus error signal Ste which will be described later, a galvanometer mirror position detection signal Sio, and an off-track signal Strk by sample servo.
Is output.

Next, FIGS. 3 to 5 show the four photodetector sections A, B, C and D of the photodetector 30 and the light receiving state of the return light F ₅ .

At this time, A, B, C, and D are equally divided into four in a matrix form in a direction Y ₂ parallel to the tracking direction and a direction parallel to the data track direction X _2, and O ₂ indicates the light detection unit a, B, C, the midpoint of D.

Then, the return light F ₅ is received over the four divided photodetectors A, B, C and D, and the focus error signal Sfe, the galvano-mirror position detection signal Sio and the sample are changed depending on the change of the light receiving state. The off-track signal Strk by the servo is output.

Then, Sfe = (A + D)-(B + C) is calculated, and Sio = (A + B)-(C + D) is calculated.
Strk = A + B + C + D.

Here, (A), (B), and (C) in FIG. 3 all show Ste = 0 (correct focus state). 3A shows Sio = 0 (state of detecting the center position of the deflection angle at the time of angle control of the galvano mirror 33 in the direction of arrow c described above), and the solid line state of FIG. 3B shows Sio. > 0 (position detection state in the negative direction from the center position of the deflection angle at the time of angle control of the galvano mirror 33 in the direction of arrow c described above), and the solid line state in FIG.
io <0 (position detection state in the positive direction from the center position of the shake angle at the time of angle control of the galvano mirror 33 in the direction of arrow c described above) is shown.

Similarly, (A), (B) and (C) in FIG. 4 and (A), (B) and (C) in FIG. 5 are both Sfe> 0 or Ste.
<0 (incorrect focus) Sio =
0, Sio> 0, and Sio <0 are shown.

Then, as shown by dotted lines in FIGS. 3B and 3C, Strk is output at the moment when the return light F ₅ spills outward from A, B, C, and D.

Next, the control circuit of the entire magneto-optical disk drive device will be described with reference to FIG.

First, the host computer CPU to SC
The system controller 52 drives the spindle motor 10 via the drive circuit 53 based on the signal input via the SI interface 51, and the spindle motor 10
Thus, the magneto-optical disk 13 is rotationally driven at high speed.

Then, the system controller 52 drives the light emitting element 29 of the optical system via the laser driving circuit 54, and the light beam F ₁ emitted from this light emitting element 29 causes the galvano mirror 33, the 45-degree reflecting mirror 34, etc. The beam spot F _{4 which} is incident on the objective lens 21 via the objective lens 21 and is converged by the objective lens 21 is applied to the recording surface side 13 a of the magneto-optical disk 13.

Then, the system controller 52 drives the focusing motor 20 via the drive circuit 55, and the objective lens 21 irradiates the recording surface side 13a of the magneto-optical disk 13 with the beam spot F _{4 in} the direction of arrow b. Do the focus.

The system controller 52 drives the galvano mirror motor 45 via the drive circuit 56 to control the angle of the galvano mirror 33 in the direction of arrow d, and the objective lens 21 controls the recording surface side of the magneto-optical disk 13. Fine tracking of the beam spot F ₄ radiated on 13a in the direction of arrow a is performed.

Further, the system controller 52 drives the linear voice coil motor 27 via the drive circuit 57, and the objective lens 21 irradiates the recording surface side 13a of the magneto-optical disk 13 with the arrow a of the beam spot F ₄ . Seek in the direction.

The system controller 52 controls the energization of the head coil 23a of the magnetic field modulation head 23 so that the magnetic field modulation head 23 modulates and demodulates the vertical magnetic field of the magneto-optical disk 13.

From the host computer CPU to S
The laser drive circuit 54 drives the light emitting element 29 by the data modulation signal output from the data recovery / modulation circuit 59 based on the data signal input to the data buffer circuit 58 via the CSI interface 51, and the laser drive circuit 54 drives the light emitting element 29. Recording (writing) is performed.

Then, the output signal from the return light F ₅ received by the four photodetectors A, B, C and D of the photodetector 30 is sent to the data demodulation circuit 59 through the reproduction signal processing circuit 60. The signal is converted into a demodulated signal and output to the host computer CPU via the data buffer circuit 58 and the SUSI interface 51 to reproduce (read) the magneto-optical disk 13.

At the same time, the light detection element 30
The divided output signals from the photodetectors A, B, C, and D are input to the matrix signal processing circuit 61. Then, the matrix signal processing circuit 61 outputs the focus error signal Sfe, the position detection signal Sio of the carbano mirror 33 and the off-track signal Strk to the system controller 52, and these three pieces of information are sent to the host computer CPU via the SCSI interface 51. Is output.

Next, the tracking operation will be described with reference to the flow chart of FIG. 2 based on the control circuit of FIG.

First, after the start, the beam spot F ₄
Is a signalless portion BS of a predetermined data track TR shown in FIG.
It is determined whether or not the beam spot F ₄ has arrived, and when the beam spot F ₄ reaches the no-signal portion BS, fine tracking of the beam spot F ₄ is performed by controlling the angle of the galvano mirror 33.

At this time, the matrix signal processing circuit 61
Is the galvanometer mirror position detection signal S shown in FIGS.
a photodetector A divided into four parts of the photodetector 30 which is an io,
The value of (A + B)-(C + D) in the light receiving state of B, C, and D is detected.

Then, the galvanometer mirror position detection signal Sio
When the galvano-mirror position detection signal Sio exceeds the reference value, the system controller 52 outputs a correction control signal to the drive circuit 57 of the linear voice coil motor 27 to output the linear control signal. The voice coil motor 27 is driven to seek the beam spot F ₄ .

The embodiment of the present invention has been described above.
The present invention is not limited to the above embodiments, and various modifications can be made based on the technical idea of the present invention. For example, in the above-described embodiment, as shown in FIGS. 3 to 5, the photo-detecting portion of the photo-detecting element 30 is divided into four matrixes, but the direction Y parallel to the tracking direction shown in FIGS.
If ₂ obtained by dividing the like into a plurality 2 divided or 3 divided,
The position of the galvanometer mirror 33 can be detected.

[0063]

The magneto-optical disk drive device of the present invention constructed as described above has the following effects.

According to a first aspect of the present invention, the photodetector element for detecting the return light of the light beam applied to the magneto-optical disk is equivalently divided into at least two parts in a direction parallel to the tracking direction.
The position of the galvano mirror that performs fine tracking is detected by determining the change in the light reception state of the return light at these two light detection units.
Since it is not necessary to attach an external sensor for position detection to the galvano mirror itself, it is possible to reduce the cost by eliminating the additional parts of the galvano mirror.
Further, since the galvanometer mirror is attached with an external sensor, there is no inconvenience that the balance of the galvanometer mirror is lost, and the balance of the galvanometer mirror can be stabilized, so it is extremely strong against vibration and shock. In addition, since the external sensor is attached to the galvanometer mirror, there is no inconvenience that the weight (inertia force) of the galvanometer mirror increases.
Can be reduced, so that the servo characteristics are not deteriorated.

According to a second aspect of the present invention, the position detecting element discriminates a change in the light receiving state of the return light due to the total reflection at the no-signal portion formed in the longitudinal direction of the data track of the magneto-optical disk. Therefore, the position detection information of the galvanometer mirror can be accurately obtained, and the angle control of the galvanometer mirror can be performed with high accuracy.

According to a third aspect of the present invention, when the position detection information of the galvanometer mirror from the photodetector exceeds a reference value,
Since the control circuit that drives the linear voice coil motor to perform the correction is provided, the angle of the galvano mirror can be accurately controlled within the effective range.

According to a fourth aspect of the present invention, the position detection information of the galvano mirror is output according to the difference in the amount of the returned light received by at least two photo detection parts of the photo detection element. Easy to do.

According to a fifth aspect of the present invention, the photo-detecting element is equivalently provided with four photo-detecting sections which are divided into four in a direction parallel to the tracking direction and the data track direction. Since the position detection information of the galvanometer mirror, the focus error information and the off-track information are obtained according to the change, only one light detection of the three information of the position detection information of the galvanometer mirror, the focus error information and the off-track information is performed. Since it can be obtained by an element, the number of parts can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control circuit that is an embodiment of a magneto-optical disk drive device of the present invention.

FIG. 2 is a flow chart illustrating the tracking operation of FIG.

FIG. 3 is a diagram showing a relationship between a change in a light receiving state of return light by a photodetector and an output signal, and particularly when the focus is correct.

FIG. 4 is a diagram showing a relationship between a change in a light receiving state of return light by the photodetector and an output signal, and particularly for explaining a case where the focus is incorrect.

FIG. 5 is a diagram illustrating a relationship between a change in a light receiving state of return light by a photodetector and an output signal, and particularly illustrating another example when the focus is incorrect.

FIG. 6 is a diagram illustrating a structure of a data track of a magneto-optical disk.

FIG. 7 is a diagram illustrating a fine tracking operation by angle control of a galvanometer mirror.

8A is a drawing for explaining a fine tracking operation of a beam spot on a data track, and FIG. 8B is a return light received by a photodetector at the time of fine tracking. FIG.

FIG. 9 is a diagram illustrating an optical system of an optical pickup.

FIG. 10 is an exploded perspective view of a galvanometer mirror.

FIG. 11 is a perspective view of a galvano mirror in a completed assembly state.

FIG. 12 is a partially cutaway plan view of a magneto-optical disk drive device.

13 is a cross-sectional view taken along the line AA of FIG.

14 is a sectional view taken along the line BB of FIG.

FIG. 15 is a perspective view of an optical system of a magneto-optical disk drive device.

[Explanation of symbols]

1 Sealed Case 10 Spindle Motor 13 Magneto-Optical Disk 16 Optical Pickup 19 Carriage 20 Focusing Unit 20a Focusing Motor for Focusing Unit 21 Objective Lens 23 Magnetic Field Modulating Head 27 Linear Voice Coil Motor 28 Optical System 29 Light Emitting Element 30 Photodetecting Element A, B , C, D photodetector section of the photodetector 30 divided into 45 motors for galvano mirrors 61 matrix signal processing circuit TR data track BS non-signal part of data track X ₁ data track direction X ₂ equivalent to data track direction Parallel direction Y ₁ Tracking direction Y ₂ Equivalently parallel to tracking direction

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ansho Kano 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Katsumi Maekawa 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation

Claims (5)

[Claims] 1. A magneto-optical disk rotatively driven by a spindle motor, an objective lens and a magnetic field modulation head for recording and reproducing the magneto-optical disk, and a light emission for emitting a light beam to the magneto-optical disk through the objective lens. An optical system including an element, a photodetection element for detecting return light reflected by the magneto-optical disc and returned through the objective lens, and a fine tracking galvanomirror for controlling an incident angle of a light beam to the objective lens; In a magneto-optical disk drive device including an optical pickup including a linear voice coil motor that moves at least the carriage to which the objective lens is attached in a substantially radial direction of the magneto-optical disk, the photo-detecting element is formed on the photo-detecting element, Equivalently at least in a direction parallel to the tracking direction It is provided with at least two photo detectors that are split and receive the return light from the objective lens straddling, and the position of the galvanometer mirror is changed according to the change in the light receiving state of the return light at the two photo detectors. A magneto-optical disk drive device, wherein detection information is output from the photodetection element to a control circuit. 2. The position detecting element discriminates a change in a light receiving state of return light due to total reflection at a no-signal portion formed in the data track of the magneto-optical disk. 1. The magneto-optical disk drive device described in 1. 3. The control circuit, when the position detection information of the galvanomirror from the photodetector exceeds a reference value,
3. The magneto-optical disk drive device according to claim 1, wherein the linear voice coil motor is driven to perform correction. 4. The position detection information of the galvano-mirror is output according to the difference in the amount of the returned light received by at least two light detection units of the light detection element. Item 3. A magneto-optical disk drive device according to item 3. 5. The photo-detecting element is equivalently provided with four photo-detecting sections divided into four in a direction parallel to the tracking direction and the data track direction, and these four photo-detecting sections are arranged to detect the return light receiving state. The magneto-optical disk drive according to claim 1, 2 or 3 or 4, wherein the position detection information, the focus error information and the off-track information of the galvano mirror are obtained by the change. apparatus.