JPH10149555A - Disk drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically adjust a spindle motor into the optimum skew state in simple constitution and also to enable the optimum skew adjustment in the case of a separate optical system by arranging actuators in more than two places of spindle motor fitting parts and making them displacable with a control signal. SOLUTION: The actuators are arranged in all or a part of fitting parts of the spindle motor to be displaced by the actuators based on the control signal, so as to control the inclining state of the spindle motor. In order to drive the actuators 24, first of all, the skew state is detected by utilizing an output of a photodetector 7. A skew error signal Erad in the radial direction and a skew error signal Etan in the tangential direction are calculated from outputs of four divided elements EA, EB, EC and ED of the photodetector 7, and based on these skew error signals, required actuators 24 are driven by a skew driver 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive, and more particularly to a skew adjustment technique for adjusting a relative angle between a disk recording surface and a laser beam from an optical pickup.

[0002]

2. Description of the Related Art As disk-shaped recording media such as optical disks and magneto-optical disks, CDs (Compact Discs),
Read-only media such as ROM, write-once media such as WO (Write Once) disk, MO (Magnet Optica)
l) Various media such as rewritable media such as discs have been developed.

A driver for such a disk medium, that is, a recording device or a reproducing device performs an operation of irradiating a laser beam to a disk by an optical pickup at the time of recording or reproducing. In this case, it is ideal that the laser irradiation is performed such that the optical axis of the laser beam is perpendicular to the recording surface of the disk.

However, it is difficult to always maintain a vertical state due to mechanical positional accuracy errors of an optical pickup, a disk chucking mechanism, and the like, disk warpage, and surface runout when the disk rotates. Further, in a disk medium having a large diameter, there is a situation in which the influence of a warped warp or the like greatly differs between the outer circumference and the inner circumference of the disk.
In order to correct the angle error between the laser beam and the disk surface while coping with such a situation, a so-called skew adjustment mechanism has been conventionally proposed. 13 and 14 show examples of the skew adjustment mechanism.

FIG. 13 shows an example in which the skew is adjusted by adjusting the angle of the optical pickup. Disc 9
Numeral 0 is fixed on the spindle motor 91 by a chucking mechanism (not shown), and is rotated by the rotation of the spindle motor 91. The optical pickup 92 is supported by guide rails 95 and 96,
96 is slidable. That is, the optical pickup 92 can be moved in the radial direction of the disk 90. The guide rails 95 and 96 are attached to a chassis (not shown). The optical pickup 92 includes a laser light source, a required optical system, a detector for detecting reflected light, and the like, and irradiates the recording surface of the disk 90 with laser light L from the objective lens 92.

[0006] An optical sensor 93 is provided integrally with such an optical pickup 92. For example, a tilt sensor having a light emitting element and a light receiving element. Then, light is emitted from the light emitting element to the recording surface of the disc 90,
The reflected light is detected by a light receiving element. The optical sensor 93 detects an angle error state of the optical pickup 92 (that is, the laser beam L) and the recording surface of the disk 90 with respect to a vertical state.

The skew motor 94 is driven according to the error value. The skew motor 94 is, for example, a mechanism that can adjust the height of one of the guide rails 95 and 96, or the guide rail 9 of the optical pickup 92.
The angle state of the optical pickup 92 is displaced by driving the skew motor 94, which is connected to a mechanism capable of adjusting the height state of the holding section with respect to the optical pickups 5 and 96. As a result, the angle between the laser beam L and the recording surface of the disk 90 is controlled to be vertical.

FIG. 14 shows an example in which the skew is adjusted by adjusting the angle of the spindle motor 91 on which the disk 90 is loaded. As shown, the spindle motor 9
A flange portion 100 is provided below 1 and the flange portion 100 is fixed to a chassis or the like (not shown). For this purpose, for example, two places are fixed to the chassis or the like by screws 98 and 98. . One position is an adjustment screw 99 (immo screw). In other words, by turning the adjustment screw 99 to adjust the length of the protrusion below the flange portion 100, the mounting angle state of the spindle motor 91 can be adjusted. With this adjustment, the relative position between the optical pickup and the spindle motor 91 is adjusted so that the optical disk of the laser beam output from the optical pickup and the disk loaded on the spindle motor 91 are in a vertical state.

[0009]

However, these skew adjustment mechanisms have the following problems. First, FIG.
When the optical sensor 93 and the skew motor 94 are provided as described above, these components increase the size and cost of the mechanism around the optical pickup. Further, this skew adjustment method is basically based on the premise that an integrated optical system is used. The integrated optical system is one in which the optical system from the laser light source to the objective lens and the optical system from the objective lens to the detector are all housed in one optical pickup unit.

On the other hand, an optical pickup called a separation optical system has been developed. For example, the entire optical pickup is divided into a movable part and a fixed part slidable in the radial direction of the disc. For example, a laser light source, a detector and a required optical system are arranged in the fixed part.
On the other hand, the movable part has a simple configuration such as only a mirror and an objective lens. Then, the laser light emitted from the fixed portion is incident on the movable portion, and is applied to the disk via the mirror and the objective lens.

In this case, if the angular state of the movable part is corrected as a skew adjustment, the positional relationship between the movable part and the fixed part on the optical path of each optical element is shifted, and the change in the angle of the movable part is, for example, about four times. The skew adjustment operation requires extremely high-precision adjustment, and in practice, it is difficult to perform a good adjustment.
In such a separation optical system, the optical path from the light source to the objective lens is precisely adjusted. On the other hand, the skew adjustment operation reduces the accuracy of the optical path.

Further, in the case of the separation optical system, the sliding movement can be accelerated by reducing the weight of the movable part, thereby shortening the seek time. However, the weight can be reduced by attaching a skew motor and an optical sensor. Will be hindered.

The example shown in FIG. 14 has the advantage that the skew can be adjusted with a very simple structure. However, this naturally requires manual adjustment, and is actually performed in the adjustment process before shipment from the factory. Only. This adjustment is performed according to the relative positional error between the spindle motor and the optical pickup. Therefore, it is not possible to adjust an error from the vertical state due to the effect of the disk warpage or surface deflection. That is, the actual recording / reproducing operation cannot always be performed in the optimum skew state.

[0014]

SUMMARY OF THE INVENTION In view of the above problems, the present invention can be automatically adjusted to an optimum skew state with a simple configuration and always suitable for a separation optical system. It is an object to provide a disk drive device provided with a skew adjustment mechanism.

For this reason, the spindle motor is mounted at at least three mounting portions in the disk drive device, and all or a part of each mounting portion performs a displacement operation based on a control signal. For example, by providing an actuator such as a piezoelectric ceramic, the tilt state of the spindle motor is controlled by a control signal.

In particular, the actuator is provided in each of the mounting portions so that the tilt state of the spindle motor can be controlled in one or both of the radial direction and the tangential direction of the disk-shaped recording medium held on the spindle motor. To all or part of The control signal generating means for generating the control signal is configured to generate the control signal based on a result of a predetermined calculation process performed on the light reflected from the disk-shaped recording medium and detected by the optical pickup. This arithmetic processing is a predetermined arithmetic processing for making the optical axis of the laser beam perpendicular to the recording surface of the disk-shaped recording medium.

Further, the control signal generating means generates a control signal based on a result of a predetermined arithmetic processing on reflected light information from the disk-shaped recording medium detected by the optical pickup at a predetermined point in time, and a value of the generated control signal. Is held for a required period of time, so that the actuator maintains a displacement operation state based on the value of the control signal generated at the predetermined time after the predetermined time. That is, the skew adjustment is performed at a specific point in time, and the state is maintained thereafter.

In such a skew adjustment mechanism, a skew error state is detected from reflected light information, so that a dedicated detection mechanism such as an optical sensor is not required. In addition, by using a piezoelectric ceramic or the like as an actuator, a skew motor is not required. Further, since the skew is adjusted by adjusting the angle on the spindle motor side, there is no adverse effect on the optical system even with the separation optical system. Of course, since the skew adjustment can be performed at any time as needed, adjustment according to an individual disk, adjustment according to a recording / reproducing position on the disk, and adjustment that absorbs the effects of aging are also possible.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A disk drive according to an embodiment of the present invention will be described below with reference to FIGS.
This disk drive device is a recording / reproducing device for a magneto-optical disk.

FIG. 1 is a perspective view of a disk drive (a so-called mechanical deck) of a disk drive device. The mechanical deck comprises an upper chassis 30 on which various mechanisms are mounted, and a lower chassis 31.
A disc (not shown) is inserted and removed from an insertion portion 32 serving as an opening between the lower chassis 31. Mounted substantially at the center of the upper chassis 30 is a bias magnet unit (bias coil) 11.

FIG. 2 is a perspective view of the mechanical deck with the upper chassis 30 and the lower chassis 31 removed.
In particular, it shows a mechanism mounted on the lower chassis 31 side. The lower chassis 31 is provided with various mechanisms necessary for recording / reproducing driving of the disk. The loaded disk is fixed on the spindle motor 1 and is driven to rotate by the spindle motor 6.

The optical pickup 2 for irradiating a rotating disk with laser light and extracting information from the reflected light is of a separation optical system type comprising a movable part 2A and a fixed part 2B. As will be described in detail later, a laser light source such as a laser diode and a laser coupler, a required optical system, a photodetector for detecting reflected light information, and the like are mounted inside the fixed portion 2B. The laser light from the laser light source is guided by the optical system inside the fixed part 2B, and is emitted from the light input / output part 33 to the outside of the fixed part 2B. The movable part 2A is in the emission direction from the light input / output part 33.
The movable section 2A is provided with a light input / output section 39 at a position coincident with the optical axis of light emitted from the light input / output section 33.

The movable section 2A is provided with an objective lens 3 serving as an output end of laser light, and a mirror (mirror 34 in FIG. 10 described later) for guiding the laser light to the objective lens 3 and is introduced from a light input / output section 39. The optical path of the laser light thus bent is bent by the mirror and guided to the objective lens 3. Then, laser light is emitted from the objective lens 3 to the recording surface of the disk rotated by the spindle motor 1.

The reflected light from the disk enters the movable section 2A from the objective lens 3, and enters the light input / output section 3 via the mirror.
9 is emitted to the fixed part 2B side. Then, in the fixed section 2B, the reflected light is taken in from the light input / output section 33, guided to the photodetector by the internal optical system, and the reflected light information is detected.

The movable portion 2A of the optical pickup 2 can be slid in the disk radial direction by a slide mechanism (not shown).

Although not shown in FIG. 2, in the case of this example, by changing the mounting angle of the spindle motor 1,
The skew correction is performed so that the tilt state of the disk is changed so that the recording surface of the disk is irradiated with the laser light from the optical pickup 2 vertically. The skew mechanism will be described later in detail.

FIG. 3 is a block diagram of the internal configuration of the disk drive of this embodiment. The magneto-optical disk 90 inserted in the mechanical deck shown in FIGS. 1 and 2 is chucked with respect to the spindle motor 1. And disk 90
Is rotated by the spindle motor 1 during data recording / reproduction.

As described above, the optical pickup 2 is divided into a movable portion 2A and a fixed portion 2B, but a laser light source 5, an optical system 6 such as a polarization beam splitter, and a photodetector 7 for detecting reflected light are fixed. 2B. An RF matrix amplifier 8 that performs various arithmetic processing on information from the photodetector 7 to obtain a necessary signal
Are also mounted in the fixed part 2B. The power and emission timing of the laser output from the laser light source 5 are controlled by a laser power controller 10.

The objective lens 3 is located inside the movable portion 2A. The objective lens 3 is held by a biaxial mechanism 4 so as to be displaceable in the radial direction of the disk 90 and in the direction of coming into contact with and separating from the disk 90. Further, as described above, the movable section 2A can be moved in the radial direction of the disk 90 by the slide mechanism 9.

As shown in FIGS. 1 and 2, a bias magnet 11 is disposed at a position facing the optical pickup 2 with the disk 90 interposed therebetween. The bias magnet 11 performs an operation of applying a bias magnetic field to the disk 90 when recording / erasing data.

Here, the principle of the recording, erasing and reproducing operations by the optical pickup 2 and the bias magnet 11 will be described. This recording / reproducing apparatus employs a so-called light modulation type magneto-optical recording system.

First, the principle of data erasure is shown in FIG. At the time of erasing, an external magnetic field for erasing is generated by the bias magnet 11. In this case, the upper part in the drawing is the S pole, and the lower part is the N pole.
Make it a pole. Then, with respect to the optical pickup 2, after the laser irradiation position (the position of the objective lens 3) is moved to a predetermined position where data is to be erased by a tracking operation by the slide mechanism 9 and the biaxial mechanism 4,
Continuous laser irradiation is performed as an output level for erasing. Thereby, in the area to be erased, the disk 9
The recording film of 0 is entirely magnetized in a certain direction according to the external magnetic field for erasure, that is, the pit information formed by the magnetic pole direction is erased.

FIG. 5 shows the principle of the recording operation after the erasure is performed as described above. At this time, an external magnetic field for recording is generated by the bias magnet 11. In this case, the upper part in the drawing is the N pole, and the lower part is the S pole, that is, the magnetic field polarity in the direction opposite to that in the erase operation. In this state, recording level laser irradiation is performed from the optical pickup 2 only at the timing when pits are to be formed. That is, the laser is turned on / off in accordance with "1" and "0" of the data to be recorded. In this case, only the portion irradiated with the laser is polarized by the bias magnet 11 according to the external magnetic field, that is, only the portion of the recording film has the opposite polarity to the other portions. This is formed as pit information according to the direction of the magnetic field.

FIG. 6 shows the principle of reproducing pit information according to the direction of a magnetic field. Regeneration is the Kerr Effect
). The Kerr effect means that when linearly polarized light is incident on a perpendicular magnetization film, the polarization direction of the reflected light rotates in the + or-direction depending on the magnetization direction of the film. FIG.
(A) shows an image in which linearly polarized laser light is incident on the recording film of the disk 90 magnetized according to data, and the reflected light is + θk or -θ.
Rotate by k.

The reflected light is converted into an intensity of light corresponding to the polarization direction by an analyzer provided in the optical system 6. The light intensity of the reflected light before and after the analyzer is shown in FIG.
(B) As shown in (c), that is, reflected light having a light intensity corresponding to the data is obtained by the analyzer,
This is converted into an electric signal by the photodetector 7, so that "1" and "0" data can be read from the disk 90.

From the reflected light information read from the photodetector 7 based on such a principle, the RF matrix amplifier 8
, The necessary signal is extracted. That is, information used for various operation controls such as a reproduction RF signal and a servo operation to be actual reproduction data is extracted. The reproduced RF signal is subjected to amplification, equalizing processing, binarization processing, and the like in the RF processing unit 14, and is converted into digital data of "1" and "0" according to the recording pit. And the read data DT _R is supplied to the system controller 15.

The system controller 15 is formed of a microcomputer, which controls the operation of the entire recording / reproducing apparatus and serves as a portion for transmitting / receiving recording / reproducing data to / from the host computer via the interface section 16. Read data DT _R from RF processing unit 14
Is a decoder 15a in the system controller 15.
The decoding process is performed in the function block as, and the data is reproduced. The reproduced data is sent to the host computer via the interface unit 16.

When recording data transmitted from the host computer via the interface unit 16 on the disk 90, the system controller 15 first encodes the data in a functional block as an encoder 15b. Generate data according to the recording format. Then, the recording data DT _W is supplied to the laser power controller 10.

As described above, at the time of recording, an external magnetic field for recording is generated by the bias magnet 11, but laser irradiation by the optical pickup 2 is turned on / off according to "1" and "0" of data to be recorded. . That is, the laser power controller 10 by turning on / off control of the light emitting operation of the laser diode 5 according to the pulse of the recording data DT _W, so that the magnetic field pit recorded based on the recording data DT _W is performed.

When such a recording / reproducing operation is performed, control on the laser irradiation position, spot diameter, laser power, rotation speed of the spindle motor 1 and the like must be properly performed. Therefore, various servo systems are configured.

As signals used for the operation of the servo system, RF
In the matrix amplifier 8, the tracking error signal TE and the focus error signal F are obtained from the output of the photo detector 7.
E, slide error signal SLE, light amount signal (sum signal) I
SUM and the like are extracted. These signals are supplied to the servo processor 18.

The servo processor 18 outputs these signals,
Various servo drive signals (focus drive signal, focus drive signal,
A tracking drive signal, a slide drive signal, and a spindle drive signal are generated, and focus servo, tracking servo, slide servo, and spindle servo are executed.

The focus servo uses the optical pickup 2
This is an operation for controlling the laser light output from the optical disc so as to focus on the recording surface of the disk 90 rotated by the spindle motor 1. In order to obtain the focus error signal FE, in the photodetector 7, for example, FIG.
A quadrant detector as shown in FIG. 1A is prepared, and focus error information is extracted by a so-called astigmatism method. That is, each element of the 4-split detector is represented by EA, E
B, EC, ED, and detectors EA, ED and EB, EC, which are paired in a diagonal direction, the RF matrix amplifier 8 outputs a current corresponding to the amount of light output from each of the elements EA, EB, EC, ED. After converting to
The calculation of (EA + ED)-(EB + EC) is performed, and the result is used as the focus error signal FE. Note that R
The F matrix amplifier 8 also performs an operation of EA + EB + EC + ED, and this is a sum signal I which is information corresponding to the light amount.
SUM.

The servo processor 18 generates a focus drive signal by performing a phase compensation process or the like on the focus error signal FE and supplies the focus drive signal to the focus driver 20. The focus driver 20 applies power to the focus coil of the two-axis mechanism 4 according to the focus drive signal, whereby the objective lens 3
It is driven in the direction of coming and going. The movement of the objective lens 3 is controlled so that the focus error signal FE always becomes zero, so that the focused state of the laser beam is maintained.

In order to realize such focus control, the objective lens 3 must be at a position within the focus pull-in range. As is already known, the focus pull-in range is a range in which the focus error signal FE changes linearly. If the focus error range is not within this range, it is possible to correctly control the zero cross point of the focus error signal FE as an appropriate focus position. Can not. Therefore, at the time of start-up for executing the recording / reproducing operation, the focus search operation is performed. In this focus search operation, power is applied to the focus coil so that the objective lens is forcibly moved within the movable range.
Then, for example, when it is detected from the above-mentioned sum signal ISUM or the like that it is within the focus pull-in range, the focus servo is turned on.

The tracking servo is an operation for controlling the laser beam output from the optical pickup 2 so as to follow the track (groove) of the disk 90 rotated by the spindle motor 1. In order to obtain the tracking error signal TE, when the laser irradiation is of the three-spot type, a detector element for a side spot is prepared in the photodetector 7, and the output of each detector element is subtracted by the RF matrix amplifier 8. , And the result can be used as the tracking error signal TE. In the case of the one-spot method, the tracking error signal TE may be obtained from the push-pull signal from the quadrant detector.

The servo processor 18 performs a phase compensation process or the like on the tracking error signal TE to generate a tracking drive signal and supplies it to the tracking driver 21. The tracking driver 21 applies electric power to the tracking coil of the two-axis mechanism 4 according to the tracking drive signal, whereby the objective lens 3 is driven in the radial direction of the disk 90. The movement of the objective lens 3 is controlled so as to be always performed in a direction where the tracking error signal TE becomes zero, so that the tracking state of the laser light is maintained.

Next, the slide servo is a control in the disk radial direction similar to the tracking servo, but by moving the movable portion 2A of the optical pickup 2 within a range that cannot be followed by the tracking servo, the output from the optical pickup 2 is controlled. This is an operation of irradiating the laser beam to a predetermined position on the disk 90.

The slide error signal SLE is a signal corresponding to the deviation of the objective lens 3 from the center position in the track direction detected by the midpoint sensor in the optical pickup 2, and the servo processor 18 outputs such a slide error signal. A slide drive signal in a direction in which SLE becomes zero is supplied to the slide driver 19. The slide driver 19 drives the slide mechanism 9 according to such a slide drive signal to move the movable section 2A. Of course, in a track jump operation such as an access operation, a slide drive signal is generated from the servo processor 18 in response to an instruction from the system controller 21 and the slide mechanism 9 is driven.

The servo processor 18 also controls the rotation of the spindle motor 1. Spindle motor 1
Is driven by the spindle driver 12. The servo processor 18 outputs a spindle start / stop signal SPSB to the spindle driver 12 in response to a spindle start command from the system controller 15.

The spindle driver 12 starts rotating the spindle motor 1 in response to the spindle start / stop signal SPSB, and outputs a spindle lock signal SPLK to the servo processor 18 when the spindle motor 1 reaches a predetermined number of revolutions. Based on the spindle lock signal SPLK, the servo processor 18 and the system controller 15 can detect that the spindle motor 1 has actually reached the predetermined number of revolutions after the spindle start command.

When the spindle stop command is received from the system controller 15, the servo processor 18 outputs to the spindle driver 12 a spindle start / stop signal SPSB whose polarity is inverted from that at the start. The spindle driver 12 generates brake power for the spindle motor 1 in accordance with the spindle start / stop signal SPSB having a different polarity, and stops the spindle motor 1.

The spindle driver 12 has an FG
A (frequency generator) 13 is provided to generate a spindle FG signal SPFG as four rectangular waves for one rotation of the spindle motor 1, for example. Since the spindle FG signal SPFG is supplied to the servo processor 18, the servo processor 18 can know the approximate rotation speed of the spindle motor 1 from the spindle FG signal SPFG, and
When the pulse interval as G exceeds a predetermined threshold value, it can be determined that the spindle rotation has stopped.

Further, the operation of the servo processor 18 includes controlling the laser output level to a constant level with respect to the laser power controller 10 and controlling the laser output level based on an instruction (at the time of recording / reproduction) from the system controller 21. High level / low level switching is performed. Further, the servo processor 18 outputs a drive signal to the bias magnet driver 22 to generate the above-described bias magnetic field for erasing and the bias magnetic field for recording on the bias magnet 11 at the time of recording / erasing.

By performing the operation of the servo processor 18 as described above, the above-described operations of erasing / recording / reproducing are properly realized. Such a servo processor 18 is actually formed as a DSP (digital signal processor).

In the present embodiment as described above, skew adjustment is performed by displacing the mounting angle of the spindle motor 1. Therefore, the actuator 24 is mounted below the spindle motor 1. Actuator 2
4 is formed of, for example, a piezoelectric ceramic. Then, the actuator 24 is driven to be displaced by the skew driver 23. The skew driver 23 generates a skew error signal E in the radial direction obtained by the RF matrix amplifier 8.
rad, skew error signal E in tangential direction
According to one or both of tan, a required voltage is applied to the actuator 24 as a skew drive signal, and the displacement operation of the actuator 24 is performed. The skew drive signal to hold output in response to the hold control signal S _H from the system controller 15 maintains the displacement state of the actuator 24.

Actuator 24 and actuator 2
4 will be described with reference to FIGS. FIG. 8 shows the spindle motor 1, the movable part 2A, and the disk 90. The spindle motor 1 is attached to the lower chassis 31 shown in FIG. 2 at a flange portion 1a formed at a lower portion thereof, and this attachment is fixed at three places of attachment portions PA, PB, and PC.

In FIG. 7, each of the mounting portions PA, PB, P
C, the actuators 24 (2
4A, 24B, and 24C) are shown, but the actuator 24 may be provided on all of the mounting portions PA, PB, and PC, or the mounting portions PA, P
Actuator 2 for one or two of B and PC
4 may be arranged.

The actuator 24 is made of a piezoelectric ceramic. When a voltage is applied to the actuator 24, the actuator 24 is displaced in accordance with the voltage, and accordingly, the mounting portions (PA, PB) on which the actuator 24 is disposed. , PC) are displaced up and down. That is, the mounting angle of the spindle motor 1 changes. Although the X, Y, and Z axes are added in the figure, the angle α between the recording surface of the disk 90 and the optical axis of the laser beam output from the movable unit 2A from the vertical state in the YZ plane is shown as α. , −
α is a skew error in the radial direction, and inclinations β and −β from the vertical state on the XZ plane are skew errors in the tangential direction.

The actuator 24 is provided to correct these skew errors.
The following examples (1) to (3) can be considered as a method of disposing the actuator 24.

The mounting portion PA is provided with an actuator 24A, and the mounting portions PB and PC are not provided with an actuator but are supported by, for example, a rotatable plastic material. An actuator 24B is provided on the mounting part PB, and the mounting parts PA and PC are supported by, for example, a rotatable plastic material without providing an actuator. The mounting portion PC is provided with an actuator 24C, and the mounting portions PA and PB are not provided with an actuator but are supported by, for example, a rotatable plastic material. Actuators 24B, 24C on mounting parts PB, PC
And the mounting portion PA is supported by, for example, a rotatable plastic material without providing an actuator. Actuators 24A, 24B on mounting parts PA, PB
And the mounting portion PC is supported by a rotatable plastic material without providing an actuator. Actuators 24A, 24C for mounting parts PA, PC
And the mounting portion PB is supported by a rotatable plastic material without providing an actuator. The actuators 24A,
24B and 24C are provided.

Here, in FIG. 7, the mounting portions PB and PC are on the axis XX, and the mounting portion PA is on an axis YY perpendicular to the axis XX and passing through the center of the spindle motor 1.
Is set.

Then, in the above case, the actuator 2
The skew adjustment in the radial direction becomes possible by the displacement of 4A. In each of the above cases, the actuator 24B
Alternatively, the skew adjustment in the tangential direction can be performed by the displacement of 24C. Further, in each of the above cases,
By displacing the required actuator, both skew adjustment in the radial direction and skew adjustment in the tangential direction become possible.

As an attachment method in which the actuator 24 is interposed in each attachment portion (PA, PB, PC), for example, an example shown in FIG. 8 or FIG. 9 can be considered.

First, in the example of FIG. 8, the coil spring 41 and the set screw 40 are used to dispose. That is, FIG.
As can be seen from FIG.
Is inserted, the set screw 40 is inserted through a hole (that is, the mounting portion PA or PB or PC) in the flange portion 1a of the spindle motor 1. And the flange 1a
The actuator 24 is interposed between the lower portion of the actuator 24 and the mounting seat surface 42, and a hole 24a is provided in the actuator 24. The set screw 40 is inserted into the hole 24a of the actuator 24 and then screwed into the mounting seat surface 42. I do. Accordingly, the mounted state is as shown in FIG. 8B, and the flange portion 1a (that is, the spindle motor 1) is mounted on the mounting seat surface 42 while being pressed against the actuator 24 by the action of the coil spring 41.

In this case, when the actuator 24 is displaced, the mounting portion (PA or PB or PC) is lifted against the bias of the coil spring 41 by the displacement.
In other words, the mounting portion is displaced in accordance with the displacement of the actuator 24, but the expansion and contraction of the coil spring 41 keeps the mounting portion pressed down on the mounting seat surface 42, so that the spindle motor 1 is always properly fixed. Will be retained.

FIG. 9 shows an example in which a leaf spring is used. In this case, a leaf spring 44 is fixed to the lower chassis with a set screw 43 or the like as illustrated. Then, the position where the free end side of the leaf spring 44 becomes the mounting portion (PA or PB or PC) on the flange 1a is pressed. Actuator 2
4 is interposed between the lower side of the flange portion 1a and the mounting seat surface 42.

In this manner, as in the example shown in FIG. 8, the mounting portion is displaced in accordance with the displacement of the actuator 24. However, the mounting portion is always pressed against the mounting seat surface 42 by the leaf spring 44. Thus, the spindle motor 1 is always maintained in a fixed state.

Next, a skew servo control operation for driving such an actuator mechanism will be described with reference to FIGS. In order to adjust the skew by driving the actuator 24, the skew state (inclination angle error) must first be detected.

In this example, this detection operation is performed using the output of the photodetector 7. That is, the four-divided detector elements (EA, EB, E
C, ED), the skew error signal Erad in the radial direction and the skew error signal Etan in the tangential direction are calculated, and the skew driver 23 controls the required actuator 24 based on the skew error signals Erad and Etan. Will be driven.

Specifically, a voltage is applied to the actuator 24A based on the skew error signal Erad. Further, a voltage is applied to one or both of the actuators 24B and 24C based on the skew error signal Etan. In the following description, it is assumed that any one of the above-mentioned items is adopted as the mounting of the actuator, and that the skew adjustment in both the radial direction and the tangential direction is possible.

FIG. 10 shows a configuration example of the optical system of the optical pickup 2. The laser light output from the laser light source 5 in the fixed part 2B of the optical pickup 2 is transmitted through a collimator lens 36 and a beam splitter 35 to a light input / output part 33.
And is introduced from the light input / output unit 39 to the movable unit 2A. Then, the optical path is refracted by 90 ° by the mirror 34, and the disk 90 is irradiated from the objective lens 3.
On the other hand, the reflected light from the disk 90 enters the movable section 2A from the objective lens 3, is refracted by the mirror 34, and proceeds to the light input / output section 39, the light input / output section 33, and the beam splitter 35. Then, the light is reflected by the beam splitter 35 and is irradiated on the photodetector 7 via the half-wave plate 37 and the lens 38.

FIG. 10 also shows the X, Y, and Z axes similarly to FIG. 7, but the Z axis corresponds to the optical axis of the laser beam output from the movable portion 2A, If the Z axis is perpendicular to the Y plane, the skew error will be zero. If a skew error exists, the above-described actuator 24 corrects the mounting angle of the spindle motor 1, that is, the XY plane, so as to be perpendicular to the Z axis.

The state of the spot on the photodetector 7 according to the skew state in the optical system as shown in FIG. 10 will be described with reference to FIG. When there is no skew error, FIG.
As shown in (a), each element EA,
Assuming that the beam spots are substantially uniformly irradiated on the EB, EC, and ED, first, if there is a skew error of an angle −α in the radial direction, the beam spots are changed as shown in FIG.
As shown in (b), the light is irradiated to the position on the element EA, EB side. When there is a skew error at an angle α in the radial direction, the beam spot is
As shown in FIG. 1 (c), the light is irradiated to the position on the side of the elements EC and ED.

Further, when there is a skew error of angle β in the tangential direction, the beam spot is
As shown in FIG. 11D, when the beam is irradiated to the position on the side of the elements EA and EC, and there is a skew error of an angle −β in the tangential direction, the beam spot is shifted to the position shown in FIG.
As shown in (e), the light is emitted to the position on the element EB, ED side.

As described above, the spot position on the photodetector 7 changes depending on the skew state in the radial direction and the tangential direction.
The skew error signals Erad and Etan can be calculated by the arithmetic processing of the outputs of A, EB, EC and ED.

The skew servo system for driving the actuator 24 is configured as shown in FIG. Since the output of each element EA, EB, EC, ED is used for skew error detection, each element EA, EB,
The outputs of the EC and ED, that is, the currents corresponding to the amounts of light, are first converted to voltages in the I / V converter 51 of the RF matrix amplifier 8. And each element EA,
Analog operation unit 52 as the output voltage of EB, EC, ED
Supplied to The analog operation unit 52 includes a plurality of adders,
A subtractor is provided, and each element EA, EB,
A required calculation process is performed on the output voltages of EC and ED.

More specifically, the analog calculation section 52 calculates the skew error signal Erad in the radial direction by the following calculation. Erad = (EA + EB)-(EC + ED)

The analog operation section 52 calculates the skew error signal Etan in the tangential direction by the following operation. Etan = (EA + EC)-(EB + ED)

The skew error signals Erad and Etan thus calculated are supplied to the skew driver 23. The skew driver 23 includes a low-pass filter 5 as a portion corresponding to the skew error signal Erad.
3. A sample / hold circuit 54 and a drive circuit 55 are provided. Similarly, a low-pass filter 56, a sample / hold circuit 57, and a drive circuit 58 are provided as parts corresponding to the skew error signal Etan.

With respect to the skew error signals Erad and Etan supplied to the skew driver 23, first, a DC component and a disk rotational frequency component are extracted by low-pass filters 53 and 56, respectively. The low-pass filters 53 and 56 cut the servo band signals (signal components such as focus servo / tracking servo) detected by the photodetector 7.

The outputs of the low-pass filters 53 and 56 are sampled by sample / hold circuits 54 and 57.
Hold output. Sample / hold circuits 54, 5
7 will perform the hold output of the sampling and subsequent sampling values in accordance with the hold control signal S _H from the system controller 15.

The hold outputs from the sample / hold circuits 54 and 57 are supplied to drive circuits 55 and 58.
The drive circuits 55 and 58 control the actuator 24 (24A, 24B or 2) in accordance with the supplied hold output signal value.
4C).

That is, in this example, the skew error in the radial direction (= skew error signal Erad) in which the actuator 24A is driven based on the skew error signal Erad obtained by the arithmetic processing of the signal detected from the photodetector 7. A skew correction system that converges to zero is constructed. In addition, a skew error in the tangential direction (= skew error signal Etan) in which actuator 24B or 24C (or both) is driven based on skew error signal Etan obtained by arithmetic processing of a signal detected from photodetector 7. A skew correction system that converges so that) becomes zero is constructed.

The reason why the sample / hold circuits 54 and 57 are provided is to maintain the correction state after the skew correction operation is performed. For example, the system controller 15 performs the skew correction operation at a predetermined time, such as when a disc is inserted or immediately after an access operation of the optical pickup. That is, when skew correction is performed immediately after an access operation or the like, the sampling / hold circuits 54 and 57 are caused to execute sampling, and thereafter, the sampled voltage values are held and output. Thus, after the skew correction time point, the voltage value for realizing the displacement for realizing the skew correction is continuously applied to the actuator 24, and the proper skew state is continuously maintained. The setting of the timing for executing the skew correction is arbitrary, and may be determined according to design circumstances, characteristics of the disk drive device, disk size, and the like.

As described above, in this example, the actuator 2
Since the mounting angle of the spindle motor 1 is corrected by 4 and the skew correction is executed, there is no problem even if the optical pickup 2 is of a separation optical system type. In addition, by employing piezoelectric ceramics or the like as the actuator 24, the skew correction mechanism does not increase in size and, of course, does not require a motor or the like.

Further, in this example, since the skew error signals Erad and Etan are extracted from the output of the photodetector 7, a dedicated skew sensor such as a photocoupler is not required, and the mechanism around the optical pickup is simplified and downsized. it can. Of course, the skew correction operation of this example can be performed at any time depending on the setting, and by correcting the skew every time a disc is loaded or every access,
An optimum skew state can always be realized according to individual disks, recording / reproducing positions on the disks, and the like.

In the above example, the skew error is detected by using a signal of the servo system which can be detected by the photodetector 7. However, an RF signal can be used. FIG. 12 shows a skew correction system capable of performing adjustments in both the radial direction and the tangential direction. However, in the case where the actuator 24 is provided as described above, the skew correction system may be used in the radial direction or the tangential direction. Needless to say, it is only necessary to construct a skew correction system corresponding to any one of the above.

[0089]

As described above, in the disk drive device of the present invention, the spindle motor is mounted at at least three mounting portions, and all or a part of each mounting portion is provided with a control signal. By disposing an actuator such as a piezoelectric ceramic that performs a displacement operation based on the control signal, the tilt state of the spindle motor is controlled by a control signal. By performing the skew correction by controlling the tilting state of the spindle motor in this way, even if the optical pickup is a separation optical system type, the skew correction operation does not adversely affect the optical path and the performance of the optical device. And a useful skew correction mechanism can be realized. In addition, by using piezoelectric ceramics as an actuator, a skew motor is not required, and simplification of the mechanism, miniaturization, and cost reduction can be promoted.

Further, the control signal generating means for generating the control signal is adapted to generate the control signal based on a predetermined arithmetic processing result on the reflected light information from the disk-shaped recording medium detected by the optical pickup. No special detection mechanism such as an optical sensor is required. This facilitates simplification, downsizing, and cost reduction of the mechanism around the optical pickup.

Further, the control signal generating means generates the control signal based on a predetermined calculation result of the reflected light information from the disk-shaped recording medium which is detected by the optical pickup at a predetermined point in time, and generates a value of the generated control signal. Is held for a required period of time, so that the actuator maintains a displacement operation state based on the value of the control signal generated at the predetermined time after the predetermined time. That is, the skew adjustment state performed at a specific point in time can be maintained, and the optimum skew state can be realized without performing the skew adjustment operation constantly and continuously. Of course, since the skew adjustment can be performed at any time as needed, adjustment according to an individual disk, adjustment according to a recording / reproducing position on the disk, and adjustment that absorbs the effects of aging are also possible.

Further, the skew angle required with the increase in the recording density in the future will become strict, but the skew adjustment can be controlled dynamically and at any time as in the present invention.
It is possible to cope with high-density disks. Also, by realizing the dynamic skew adjustment of the present invention, in other words, the mechanical mounting accuracy of the spindle motor is not so required, and the process can be made more efficient.

[Brief description of the drawings]

FIG. 1 is a perspective view of a mechanical deck of a disk drive device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the inside of a mechanical deck of the disk drive device according to the embodiment;

FIG. 3 is a block diagram of the disk drive device according to the embodiment;

FIG. 4 is a diagram illustrating the principle of erasing a magneto-optical disk.

FIG. 5 is an explanatory diagram of a recording principle of a magneto-optical disk.

FIG. 6 is an explanatory diagram of a principle of reproducing a magneto-optical disk.

FIG. 7 is an explanatory diagram of an actuator attached to the spindle motor according to the embodiment.

FIG. 8 is an explanatory diagram of an arrangement example of the actuator according to the embodiment.

FIG. 9 is an explanatory diagram of an example of disposing an actuator according to the embodiment.

FIG. 10 is an explanatory diagram of an optical system and a skew state of the optical pickup according to the embodiment;

FIG. 11 is a diagram illustrating a relationship between a skew state and a spot position on a detector according to the embodiment.

FIG. 12 is a block diagram of a skew correction system according to the embodiment.

FIG. 13 is an explanatory diagram of a conventional skew correction method.

FIG. 14 is an explanatory diagram of a conventional skew correction method.

[Explanation of symbols]

1 spindle motor, 2 optical pickup, 2A
Moving part, 2B fixed part, 3 objective lens, 5 laser light source, 7 photodetector, 11 bias magnet, 15 system controller, 23 skew driver, 24, 24A, 24B, 24C actuator, 52 analog operation section, 53, 56 low-pass filter, 54, 57 sample / hold circuits, 55, 5
8 Drive circuit, PA, PB, PC mounting part

Claims (6)

[Claims] 1. A disk drive device for irradiating a recording surface of a disk-shaped recording medium with a laser beam by an optical pickup while holding and rotating the disk-shaped recording medium on a spindle motor, wherein the spindle motor is In the disk drive device, at least three or more mounting portions are mounted, and all or a part of each of the mounting portions is provided with an actuator that performs a displacement operation based on a control signal. A disk drive device characterized in that an inclination state of the spindle motor is controlled by a control signal. 2. The disk drive device according to claim 1, wherein said actuator is formed of piezoelectric ceramics. 3. The mounting device according to claim 1, wherein the actuator is configured to control a tilting state of the spindle motor in one or both of a radial direction and a tangential direction of the disk-shaped recording medium held on the spindle motor. 2. The disk drive device according to claim 1, wherein the disk drive device is arranged in all or a part of the units. 4. A control signal generating means for generating the control signal based on a result of a predetermined arithmetic processing on reflected light information from a disk-shaped recording medium detected by the optical pickup. 2. The disk drive device according to 1. 5. The control signal generating means causes an optical axis of a laser beam emitted from the optical pickup to be perpendicular to a recording surface of a disk-shaped recording medium held on a spindle motor. 5. The disk drive device according to claim 4, wherein a predetermined arithmetic process using reflected light information is performed for the generation, and a control signal is generated based on the result. 6. The control signal generating means generates the control signal based on a predetermined calculation result of reflected light information from a disk-shaped recording medium detected by the optical pickup at a predetermined time, and generates the control signal. The configuration is such that the value of the signal can be held for a required period, so that the actuator maintains a displacement operation state based on the value of the generated control signal after the predetermined time point. Item 5. The disk drive device according to item 4.