JP2000173081A - Disk apparatus and driving method for head of disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disk apparatus in which the defocus in a focusing operation is eliminated and in which the quality of a recording or reproducing signal can be made best when various disks are reproducing and even when a warpage exists on the disks. SOLUTION: A focus control part 7 which drives an optical head to a focusing direction is provided with a phase compensation part 14 which compensates the phase of a focus error signal FE. In addition, it is provided with a side- runout-component extraction part 20 which detects a side-runout-frequency component at the rotating frequency of an optical disk or at a frequency at its integral multiple. In addition, it is provided with a bowl-shaped-warpage extraction part 81 which extracts an offset component corresponding to the bowl-shaped warpage of the optical disk. In addition, it is provided with a switch 21, a switch 82 and an adder 80 which selectively add the side-runout- frequency component and the offset component to the focus error signal whose phase is compensated. On the basis of the output of the adder 80, the focus drive signal FD of the optical head is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device for changing the rotational speed (linear speed) of a disk medium in accordance with the radius of a position where the disk medium is reproduced or recorded, and a disk device applied to the disk device. The present invention mainly relates to servo control for maintaining a constant distance between a head and a disk, for example, control of a focusing servo in an optical disk.

[0002]

2. Description of the Related Art Various techniques related to servo control in a disk apparatus for changing the rotation speed, that is, the linear velocity of the disk in accordance with the radius of the position where the disk is reproduced or recorded, have been conventionally known. Hereinafter, some examples of the conventional technology will be described.

[0003] For example, a servo apparatus for a rotary recording medium described in Japanese Patent Application No. 60-248707, Japanese Patent Application No. 61-12 / 1986.
No. 9125, a servo system for a rotary recording medium described in Japanese Patent Application No. 61-129126, a servo system for a rotary recording medium described in Japanese Patent Application No. 61-134801, and a servo system for a rotary recording medium described in Japanese Patent Application No. 61-134801. A servo circuit for a rotary recording medium described in Japanese Patent Application Laid-Open No. 62-29541 has a circuit having a transfer characteristic such that a peak value changes in accordance with a change in an eccentric fundamental frequency of the rotary recording medium and a change in a high-frequency component thereof. A technique has been disclosed in which the power consumption of a servo device is reduced and the steady-state deviation is reduced by including the following. In particular, Japanese Patent Application No. 60-24
Japanese Patent Application No. 8707 discloses an example using a digital filter, Japanese Patent Application No. 61-129125 discloses an example using a comb filter, and Japanese Patent Application No. 61-129126 discloses an eccentricity tracking filter that can be switched on and off. In Japanese Patent Application No. 61-134801, an initial value setting circuit is provided. In Japanese Patent Application No. 62-29541, an actuator phase compensating circuit is used as an analog circuit and a circuit having an eccentric component tracking characteristic is used. An example is disclosed as a digital circuit.

Further, the disk device described in Japanese Patent Application No. Hei 5-172540 detects a rotation speed and gives a filter coefficient in accordance with the rotation speed. Such a technique is disclosed.

[0005]

Here, servo error components during recording or reproduction of an optical disk mainly include a tracking error component and a focus error component.

For example, as an example of the cause of the occurrence of the tracking error component, in the case of so-called disk eccentricity,
The frequency fluctuation component caused by the eccentricity becomes a frequency fluctuation component that is one time the disk rotation frequency, and is added to the tracking error signal. However, the tracking system of the disk device is composed of a tracking actuator and a traverse mechanism. The traverse mechanism removes a DC component generated in a tracking error signal when a recording or reproduction position moves in a disk radial direction. It is possible. Therefore, at the time of recording or reproduction, there is no problem even if a frequency fluctuation component due to, for example, eccentricity of the disk is added to the tracking error signal.

[0007] The servo apparatus for rotating recording media described in Japanese Patent Application No. 60-248707 is disclosed in Japanese Patent Application No. 61-248707.
The servo system for a rotary recording medium described in Japanese Patent Application No. 129125 and the servo system for a rotary recording medium described in Japanese Patent Application No. 61-129126 apply to a rotational synchronization deviation component such as an eccentric fundamental wave frequency and its high frequency component. All components are configured to take countermeasures, and the DC compensation is performed by the phase compensation unit. Further, in the technology described in these publications, for example, a filter used for a servo circuit is constituted by a digital filter, so that the filter of the eccentric fundamental wave frequency and its high frequency component has a frequency characteristic of １ ／ of the sampling frequency. It is easily realized with a filter. However, as the frequency characteristic of the filter approaches の of the sampling frequency, the roughness of the output signal becomes more conspicuous, and the signal quality is expected to deteriorate. In addition, when a plurality of frequencies such as a fundamental frequency and a double frequency are incorporated into each of them, the operation time becomes a problem.

On the other hand, the following problems have been considered as problems in the focus servo at the time of recording or reproduction on the optical disk.

That is, the disk device is usually designed to rotate the optical disk by the disk motor while pressing the optical disk against the turntable by the disk pressing means. At this time, for example, small dusts and the like are generated between the optical disk and the turntable. If the optical disc is caught between the optical discs, the optical disc is deformed by the dust or the like, causing warpage. Alternatively, even when the pressing pressure of the disk pressing means when pressing the optical disk against the turntable is not uniform, the optical disk is deformed and warped. It is anticipated that at least one of these warpages exists on the circumference of the same radius of the disk, and depending on the number of dust and the state of the disc holding, there are several locations on the circumference of the same radius. Is done.

As described above, when the optical disk is warped due to dust or the state of the disk pressing, when the optical disk is rotated, so-called surface run-out occurs. For example, the frequency of the surface deflection becomes twice the disk rotation frequency if there are two warped portions per optical disk rotation. For example, if the warped portion exists three times per optical disk rotation, the frequency of the disk rotation frequency becomes two times. It is tripled. More generally, the frequency of the surface deflection of the optical disk due to the above-described warpage is such that
If there are n pieces per circumference, it becomes n times the disk rotation frequency. However, even if there are two warped portions, for example, if the distribution of the warped portions is very close to each other, it may act in the same way as one.

The influence of the above-mentioned surface runout is caused by a change in the distance between the optical head (optical pickup) and the optical disk signal recording surface on the circumference of the same radius of the disk.
That is, it appears as a change in the distance in the focus direction. Therefore, when the optical disk is subject to surface wobble during reproduction or recording, a frequency fluctuation component due to the surface wobble is added to the focus error signal.

However, in general, the focus system of the optical head of the disk drive is composed of only a focus actuator that drives an objective lens and focuses a laser beam on a disk signal recording surface. That is, the steady value of focusing is
It is designed in accordance with the amplitude center of the surface runout expected to occur on the optical disc. For this reason, usually, even if a frequency fluctuation component due to surface shake is added to the focus error signal as described above, it is possible to maintain the focal point of the laser beam by the focus servo.

In recent years, there have been various types of optical disks, and for example, some types of optical disks have different required focal lengths.

As an example of an optical disk having a different required focal length, there is, for example, a multilayer disk having a multilayered signal recording surface in one optical disk.

In the case of this multi-layer disc, when recording or reproducing, switching of the signal recording surface to be used (layer switching)
Control is required, and this layer switching control is performed in the same manner as the one-track jump control at the time of so-called track jump. That is, track jump 1
Track jump control is generally performed using a control method called bang-bang control, and the same control method as the bang-bang control is applied to disc layer switching control.

The bang-bang control at the time of switching the layer of the disc means that the state of focusing on a certain layer (hereinafter referred to as a first layer) is changed to another layer (hereinafter referred to as a second layer). In the case where the focusing is switched, first, the focus servo is turned off and an acceleration pulse for driving the focus actuator in the direction from the first layer to the second layer is generated. When the focus actuator moves by a distance corresponding to, for example, a half of the distance between the first layer and the second layer, an acceleration pulse (a deceleration pulse for decelerating) is generated in a direction opposite to the moving direction of the focus actuator. Then, the control is such that the focus servo is turned on when the distance corresponding to the target second layer is reached.
The acceleration pulse and the deceleration pulse are calculated by adding an acceleration value or a deceleration value to a steady value when focusing on the current layer. Note that the steady value in the case of tracking is zero because the offset amount has been removed by the traverse mechanism.

As described above, various types of optical disks have appeared in recent years, and it is desired that a disk device can also support these various types of optical disks.

However, as described above, in the case of a disk device capable of supporting various types of optical disks having different required focal lengths, for example, the movable center of the focus actuator of the optical head, that is, the steady value of focusing,
As described above, it is impossible to design the optical disk in accordance with the amplitude center of the surface runout expected to occur on one type of optical disk. In other words, even if only one type of optical disc can cope with surface wobble, if it cannot cope with another type of optical disc wobble, it will be impossible to record or reproduce various types of optical discs.

However, if the movable center of the focus actuator (steady value of focusing) is not adjusted to, for example, the amplitude center of the surface shake of any type of optical disk, a signal obtained by simply phase-compensating the focus error signal is obtained. When the focus actuator is driven as a drive signal, the focal point of the laser beam is deviated by an amount corresponding to the deviation of the amplitude center of the surface deflection of the optical disc from the movable center (steady value of focusing) of the focus actuator. As a result, the quality of the recorded or reproduced signal is lost at the best.

Further, the warpage of the optical disc is not limited to the above-mentioned dust and the state of the disc pressing, but also the optical disc itself may be warped due to external factors such as temperature and humidity. The warp of the optical disk caused by the temperature, the humidity, and the like is such that, for example, the outer circumference is lowered (or raised) with respect to the center of the optical disk.
It is said to appear as a bowl-shaped warp. This bowl-shaped warpage is considered to have the same amount of warp on the circumference of the same radius of the disk.

Therefore, for example, when the bowl-shaped warped optical disk is loaded into a disk device to perform reproduction or recording, the recording or reproduction position on the optical disk is moved in the radial direction. As
The distance from the optical head (optical pickup) to the signal recording surface of the optical disk gradually increases (or decreases).

For this reason, for example, when the distance from the optical head to the optical disk signal recording surface becomes large, the focus actuator of the optical head of the disk device drives the objective lens in a direction protruding from the optical head to record the optical disk signal. Focus the laser light on the surface, conversely, when the distance from the optical head to the optical disk signal recording surface is reduced, the focus actuator,
The laser light is focused on the optical disk signal recording surface by driving the objective lens in the direction of being retracted into the optical head.

However, with the bowl-shaped warping described above,
Warpage caused by dust and disc holding condition is 1
It may occur at the same time when recording or reproducing on two optical disks. As described above, when reproducing or recording an optical disk which is simultaneously generated with the bowl-shaped warpage and the warpage caused by the dust and the disc holding state, a frequency fluctuation component caused by the surface wobble is generated with respect to the focus error signal. An error component resulting from the bowl-shaped warpage is added to the buckle.

In such a case, the movable center of the focus actuator (steady value of focusing) does not match the center of the amplitude of the surface deflection of the optical disk warped in the bowl shape. Therefore, for example, the focus error signal is simply phase-compensated. By simply driving the focus actuator using the signal as the drive signal, only the bowl-shaped warpage
The focal point of the laser beam shifts, and as a result,
The quality of the recorded or reproduced signal is lost at best.

This problem becomes more conspicuous in an optical disk apparatus for recording or reproducing a plurality of types of disks, when each disk has a bowl-shaped warp.

Conventionally, as a countermeasure against defocusing of a laser beam on a disk signal recording surface, conventionally, for example, after a focus servo is turned on, an offset adjustment of a focus error signal is performed, or a focus actuator for pulling a focus is used. The focus drive signal is held, and the focus actuator is driven by a signal obtained by adding the signal obtained by phase-compensating the focus error signal and the held lamp drive value. The correction has been made.

However, when the offset of the focus error signal is adjusted after the focus servo is turned on,
Further, even if the lamp drive value at the time of focus pull-in is stored and a process of adding it to the phase compensation signal later is performed, for example, if the bowl-shaped warp occurs on the optical disc, the offset is sometimes used. Minutes need to be corrected.

The present invention has been made in view of the above-described problems, and eliminates the defocusing at the time of focusing when reproducing various types of discs and when the discs are warped. Another object of the present invention is to provide a disk device and a method of driving the head of the disk device, which can optimize the quality of a recording or reproduction signal.

[0029]

In order to solve the above-mentioned problems, a disk drive according to the present invention comprises: a head driving means for driving a head for recording and / or reproducing data on and from a disk medium; Position error detection means for detecting a position error of the head with respect to a medium, rotation drive means for rotating and driving the disk medium, and rotation error component detection means for detecting a deviation component of the rotation frequency of the disk medium or a frequency that is an integral multiple thereof. Phase compensating means for compensating for the position error detected by the position error detecting means, and selectively adding the rotational deviation component detected by the rotational deviation component detecting means to the position error after the phase compensation by the phase compensating means. And an output signal of the adding means as a driving signal of the head driving means.

Here, the disk device according to the present invention further comprises offset component detecting means for detecting an offset component due to warpage of the disk medium from the position error after the phase compensation by the phase compensating means. Then, the rotational deviation component detected by the rotational deviation component detection means and the offset component detected by the offset component detection means are selectively added to the position error after the phase compensation by the above.

Further, the disk device according to the present invention includes holding means for holding an augmented value for the position error after the phase compensation when the position error of the head with respect to the disk medium is zero. When the addition is temporarily stopped and then restarted, the rotation error component and the value to be added held in the holding means are selectively added to the position error.
At this time, the adding means updates the offset component held in the holding means.

Further, the rotational deviation component detecting means of the disk device according to the present invention detects a deviation component having a maximum value among deviation components of the rotational frequency of the disk medium or a frequency that is an integral multiple of the rotational frequency.

Next, in order to solve the above-mentioned problems, a head driving method for a disk drive according to the present invention comprises the steps of: detecting a position error of a head for performing recording and / or reproduction on a disk medium; Detecting a deviation component of the rotation frequency of the disk medium or an integer multiple thereof, performing a phase compensation of the detected position error, and selectively adding the rotation deviation component to the position error after the phase compensation. And a step of using the signal obtained by the addition as a drive signal for driving the head.

The head driving method for a disk drive according to the present invention further comprises a step of detecting an offset component of the position error of the head with respect to the disk medium from the position error after the phase compensation. The rotation deviation component and the offset component are selectively added.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of an optical disk recording / reproducing apparatus according to an embodiment to which the disk apparatus of the present invention is applied. FIG. 1 mainly illustrates a signal reproducing system and a focus servo system, and omits other components such as a signal recording system and a tracking servo system.

In FIG. 1, the optical disk recording / reproducing apparatus is configured such that a plurality of types of optical disks 1 including the above-mentioned multilayer disk can be replaced, for example, and the optical disk 1 is pressed on a turntable by disk pressing means (not shown). Can be

The spindle motor 6 drives the optical disc 1 so that the linear velocity is constant or the linear velocity changes stepwise depending on the area. The spindle motor 6 has:
An FG signal generator is provided, and the FG signal generator generates an FG signal corresponding to the motor rotation speed (disk rotation speed). This FG signal is sent to a controller 8 described later.

The optical head (optical pickup) 2 includes a laser oscillator, an optical system including an objective lens, a photodetector 3, an actuator for driving the objective lens in the focusing and tracking directions, and the like. In the following description, a portion of the actuator that controls driving in the focus direction will be referred to as a focus actuator unit. Photodetector 3 is A,
B, C, and D photo detectors are provided.
The light receiving signal of the split photodetector is sent to the signal generation unit 4 as a reproduction RF signal. The actuator of the optical head 2 is supplied with a focus drive signal FD from a focus control unit 7 described later, and the actuator is driven in the focus direction by the focus drive signal FD.

The signal generating section 4 extracts the signal of A + C + B + D from the received light signals of the four-divided photodetector of the optical head 2 as a reproduction RF signal from the disk, and
C)-(B + D) is extracted as a focus error signal FE. The focus error signal FE corresponds to a detection signal of a position error of the focus actuator of the optical head 1 in the focus direction. Further, the signal generation unit 4 performs signal processing such as analog / digital conversion, demodulation, error correction, and decoding on the reproduction RF signal from the optical head 2 to generate a reproduction signal of the optical disc 1. This reproduced signal is sent from a terminal 5 to a subsequent configuration (not shown).

The controller 8 controls the entire operation of the optical disk recording / reproducing apparatus, and controls the focus control unit 7.
In addition to the focus control signal FC for controlling the operation of the above, output enable signals EN1 and EN2 and a calculation result storage enable signal SE described later are generated and sent to the focus control unit 7.

The focus control section 7 generates a focus drive signal FD based on the focus control signal FC from the controller 8 and the focus error signal FE from the signal generation section 4, and the actuator of the optical head 2 is generated by the focus drive signal FD. Is driven in the focus direction. Note that usually, the focus error signal FE
Is very narrow as compared with the movable range in the focus direction of the actuator (the movable range of the focus actuator unit).
First, a drive signal that changes in a ramp shape is given to the focus actuator unit, and the focus actuator unit is moved until a focus error signal is generated. Next, when the focus actuator unit comes into the detection range of the focus error signal, focusing is performed by switching the drive signal to the focus actuator unit from a ramp-shaped drive signal to a phase compensation signal.

The focus control unit 7 uses the output enable signals EN1 and EN2 from the controller 8 and the calculation result storage enable signal SE to thereby determine the type and warp (surface deflection and bowl) of the optical disc 1 as described later. Achieve focus servo that is not affected by mold warpage.

FIG. 2 shows a specific example of the configuration of a focus control unit 7 which realizes a focus servo which is not affected by the type and warpage of a disc (especially, warpage that causes surface deflection) as a first embodiment of the present invention. Is shown. FIG. 2 shows an example of a configuration in which the phase compensation of the focus system and the extraction of the surface vibration frequency component of the disk are realized by a digital circuit.

In FIG. 2, a focus error signal FE from the signal generator 4 of FIG. 1 is input to a terminal 10, and the focus error signal FE is sent to an anti-aliasing filter 11.

This anti-aliasing filter 11
This is a filter for removing so-called aliasing noise from the focus error signal FE. In the present embodiment, for example, the sampling frequency SP of the digital filter
A filter that limits the band of the focus error signal is used at a frequency equal to or less than 1/2 of 1. The focus error signal output from the anti-aliasing filter 11 is sent to the switch 12.

The switch 12 and the sampling pulse generator 22 are provided as sampling means for sampling the focus error signal via the anti-aliasing filter 11, and the sampling pulse generator 2
2 as a master clock generated, for example, 88.4K
Switch 12 in response to the sampling pulse SP1 of 1 Hz.
Is turned on / off, thereby sampling the focus error signal. The focus error signal discretized by the sampling in the switch 12 and the sampling pulse generator 22 is sent to an A / D (analog / digital) converter 12.

Further, the sampling pulse generation unit 23
For example, it is controlled by a focus control signal FC from the controller 8, and a sampling pulse synchronized with the disk rotation frequency from the disk rotation speed information, that is, a sampling pulse S corresponding to the FG signal.
Generate P2. This sampling pulse SP2 is sent to the surface runout component extraction unit 20.

The A / D converter 12 quantizes the focus error signal discretized by the sampling means at the preceding stage and outputs it as a digital focus error signal.
The focus error signal digitized by the A / D converter 12 is sent to the phase compensating unit 14 and the surface shake component extracting unit 20.

The phase compensator 14 performs phase compensation so that the polarity of the focus error signal matches the polarity of the focus actuator in the direction of movement on the focus axis. The digital focus error signal after phase compensation by the phase compensator 14 is sent to the adder 15.

The surface vibration component extraction unit 20 outputs the master clock from the sampling pulse generation unit 22 as 8 clocks.
Based on the sampling pulse SP1 of 8.4 KHz and the sampling pulse SP2 corresponding to the RF signal synchronized with the disk rotation frequency from the sampling pulse generating unit 23, the frequency component due to the disk runout of the disk from the digitized focus error signal. Is extracted.

Here, the surface vibration frequency extracted by the surface vibration component extraction unit 20 is, for example, the disk rotation frequency if one warped portion exists on the same circumference at the same radial position of the disk. It becomes 1 times, and if there are two warped portions, it becomes twice the disk rotation frequency. Similarly, if there are 3 warped portions, it becomes 3 times the disk rotation frequency. In other words, if there are n warped portions on the same circumference at the same radial position on the disk, a surface deflection component having a frequency n times the disk rotation frequency can be obtained. In the case of the present embodiment, the surface vibration component extraction unit 20 extracts the surface vibration frequency component having the largest amplitude as the surface vibration frequency component that has the greatest influence on the focus servo. Although the details of the specific configuration of the surface vibration component extraction unit 20 will be described later, the surface vibration component extraction unit 20 extracts, among the surface vibration frequency components, particularly the surface vibration frequency component having the maximum amplitude value. The extracted surface vibration frequency component is sent to the switch 21.

The switch 21 is connected to an output enable signal EN supplied from the controller 8 of FIG.
The output of the switch 21 is sent to the adder 15. That is, the switch 21 is switching means for switching whether or not to selectively add the surface vibration frequency component to the digital signal after the phase compensation in accordance with the output enable signal EN1 from the controller 8. The details of the output enable signal EN1 generated by the controller 8 will be described later.

In the adder 15, the surface vibration frequency component via the switch 21 (the surface vibration determined to be added by the output enable signal EN1 of the controller 8) to the digital focus error signal after the phase compensation by the phase compensation unit 14. Frequency component). In the adder 15, the digital focus error signal to which the surface vibration frequency component has been selectively added is sent to a D / A (digital / analog) converter 16.

The D / A converter 16 converts the digital focus error signal from the adder 15 into an analog signal, that is, converts discrete quantized data into a continuous waveform signal. The waveform signal analogized by the D / A converter 16 is sent to a smoothing filter 17.

The smoothing filter 17 performs a smoothing filter process for removing a noise component existing in the waveform signal from the D / A converter 16 to obtain a smooth waveform. This smoothing filter 17 is also specifically similar to the anti-aliasing filter 11 described above.
1/2 of sampling frequency SP1 of digital filter
This is a filter that limits the band below the frequency of. The analog waveform signal passing through the smoothing filter 17 is
It is sent to the drive circuit 18.

The drive circuit 18 is mainly constituted by a power amplifier, amplifies the analog waveform signal from the smoothing filter 17, and outputs it as a focus drive signal FD for driving the focus actuator in the focus direction. I do. This focus drive signal FD is sent from the terminal 19 to the actuator (in this case, the focus actuator unit) of the optical head 2 in FIG.

As described above, in the focus control unit 7 having the configuration shown in FIG. 2, the signal obtained after the phase compensation of the focus error signal is added to the wobble frequency component having the maximum amplitude among the wobble frequency components of the disk. Is generated, and a focus drive signal FD is generated from the signal after the addition, so that even if the recording / reproducing position of the optical disc 1 moves and the rotation frequency changes, a focus servo that can follow the surface shake of the optical disc 1 Is feasible.

Next, FIG. 3 shows a specific configuration example of the surface shake component extraction unit 20 of the focus control unit 7 of the first embodiment shown in FIG.

In FIG. 3, a digitized focus error signal from the A / D converter 13 in FIG. 2 is supplied to a terminal 30. The focus error signal input to the terminal 30 is sent to the switch 31.

The switch 31 is turned on / off by a sampling pulse SP 1 from the sampling pulse generator 22 supplied via a terminal 42. That is, the switch 31 is provided as a sub-sampling unit for sub-sampling the focus error signal from the terminal 30 by being turned on / off by the sampling pulse SP1. The signal sub-sampled by the sampling pulse SP 1 in the switch 31 is sent to the sub-sampling filter 32.

The sub-sampling filter 32 is a filter for limiting a frequency band of １ ／ of a sampling frequency of a digital filter (surface shake component extraction filter). The signal that has passed through the sub-sampling filter 32 is then output to the sub-sampling filter output storage 33
Sent to

Sub-sampling filter output storage section 33
Is delay means for temporarily storing and outputting the sub-sampled signal. The signal output from the sub-sampling filter output storage unit 33 is sent to the switch 34.

The switch 34 is turned on / off by a sampling pulse SP 2 from the sampling pulse generator 23 supplied via a terminal 43. That is, in this switch 34, RF
The signal from the sub-sampling filter output storage unit 33 is sampled by being turned on / off by the sampling pulse SP2 corresponding to the signal. The signal sampled by the sampling pulse SP2 at the switch 34 is output to a surface shake component extraction filter 35.
Sent to

The surface runout component extraction filter 35 is a digital filter, and a filter coefficient is set by a configuration from a maximum value detecting section 38 to a plane runout frequency determining section 41 which will be described later. This is a filter for extracting a surface vibration frequency component from a signal. That is, the surface runout component extraction filter 35
When a filter coefficient for extracting a frequency that is one time the disk rotation frequency is set, a surface vibration frequency component of the frequency that is one time that is extracted is extracted.
When the filter coefficient for extracting the double frequency is set, the surface vibration frequency component of the double frequency is extracted,
Further, when a filter coefficient for extracting a frequency three times the disk rotation frequency is set, by setting the filter coefficient, n times the disk rotation frequency is set so as to extract the surface vibration frequency component of the triple frequency. This is a filter that can extract the surface vibration frequency components up to. The surface vibration frequency component output from the surface vibration component extraction filter 35 is sent to the surface vibration component extraction filter output storage unit 36.

The surface runout component extraction filter output storage unit 3
The surface vibration frequency component once stored in 6 is read out and sent from the terminal 37 to the switch 21 in FIG.

Here, the filter coefficient of the surface shake component extraction filter 35 is set as follows, for example.

First, in the initial state, the enable signal EN1 supplied from the controller 8 is a signal for turning off (ie, opening) the switch 21 of FIG. 1x, 2x, 3x, 4x of disk rotation frequency,
.., The detection frequency of the surface shake component extraction filter 35 is sequentially set to each of n times the frequency. In the maximum amplitude detector 38,
The maximum amplitude value of the supplied signal is detected for each of the sequentially set detection frequencies.

The maximum amplitude value detected by the maximum amplitude detection unit 38 for a frequency that is one time the disk rotation frequency is stored in, for example, a maximum amplitude value storage unit 39, and then the maximum amplitude value that is twice the disk rotation frequency is detected. The detected maximum amplitude value is stored in, for example, the maximum amplitude value storage unit 40. The maximum amplitude values stored in the maximum amplitude value storage units 39 and 40 are thereafter read out and sent to the surface vibration frequency determination unit 41. At this time, the surface wobble frequency determination unit 41 determines that the supplied disk rotation frequency is 1
The magnitudes of the maximum amplitude values of the doubled and doubled frequencies are compared, and the comparison result is stored.

Next, the maximum amplitude value detected by the maximum amplitude detection unit 38 for a frequency three times the disk rotation frequency is stored in, for example, a maximum amplitude value storage unit 39, and then the frequency is four times the disk rotation frequency. The maximum amplitude value detected for is stored in the maximum amplitude value storage unit 40, for example.
The maximum amplitude values stored in the maximum amplitude value storage units 39 and 40 are thereafter read out and sent to the surface vibration frequency determination unit 41. At this time, the surface vibration frequency determination unit 41
Then, the magnitudes of the respective maximum amplitude values at frequencies three and four times the supplied disk rotation frequency are compared, and the comparison results are stored.

Similarly, the maximum amplitude detection unit 38
The maximum amplitude values sequentially detected for each of the five times, seven times,... Of the disk rotation frequency are sequentially stored in the maximum amplitude value storage unit 39, read out, and sent to the surface wobble frequency determination unit 41. And 6 times the disk rotation frequency, 8
,... Are sequentially stored in the maximum amplitude value storage unit 40, read out, and sent to the surface wobble frequency determination unit 41. The plane runout frequency determination unit 41 compares the magnitudes of the maximum amplitude values of the five times and six times the supplied disk rotation frequency, and compares the magnitudes of the maximum amplitude values of the seven times and eight times the supplied frequencies. ,... Are sequentially performed, and the respective comparison results are stored.

After that, when the comparison result of the maximum amplitude values up to n times the disk rotation frequency is completed, the surface deflection frequency determination unit 41 selects the frequency having the largest maximum amplitude value from the comparison results, and determines the frequency as the surface frequency. Determined as the shake frequency. When the surface wobble frequency is determined, the surface wobble frequency determination unit 41 changes the filter coefficient in the initial state, and extracts a component of the determined surface wobble frequency to the surface wobble component extraction filter 35. Set and supply filter coefficients. As a result, the surface vibration component extraction filter 35 extracts only the surface vibration frequency component having the largest amplitude value from the signal of the switch 34 in the preceding stage. At this time, the enable signal EN1 output from the controller 8 turns on (closes) the switch 21.
It's a signal like

Next, FIG. 4 shows a specific configuration example of the focus control section 7 in the case of the second embodiment of the present invention. FIG. 4 shows an example of a configuration in which both phase compensation of the focus system and extraction of the surface vibration frequency component of the disk are realized by an analog circuit.

In FIG. 4, a focus error signal FE from the signal generator 4 of FIG. 1 is input to a terminal 50, and the focus error signal FE is directly transmitted to the phase compensator 51 and the surface shake component extractor 55. Sent.

The operation of the phase compensator 51 is basically the same as that of the phase compensator 14 in the first embodiment shown in FIG. 2 except for performing analog processing. Has a filter characteristic having a relationship between a gain and a frequency as shown in FIG. 5A and a phase and a frequency as shown in FIG. 5B, and has a polarity of the focus error signal FE. The phase compensation is performed by the analog filtering process so that the polarity of the focus actuator unit in the moving direction on the focus axis matches.

The operation of the surface vibration component extraction unit 55 is basically the same as that of the surface vibration component extraction unit 20 of the first embodiment shown in FIG. 2 except for performing analog processing. The surface vibration component extraction unit 55 in the case of FIG. 4 has a filter characteristic having a relationship between the gain and frequency shown in FIG. 6A and the phase and frequency shown in FIG. As shown in FIG. 7, the rotation frequency at the innermost circumference of the disk has a peak, and the change in FG due to the rotation frequency of the disk is the change in the peak frequency of the filter. 7A and 7B, the analog filter processing with the filter characteristic having the relationship between the phase and the frequency as shown in FIG. To extract a minute. As described above, since the filter of the surface vibration component extraction unit 55 has no gain in the low frequency range, the output does not saturate. The specific configuration of the surface shake component extraction unit 55 will be described later.

Therefore, according to the phase compensating section 51 and the plane runout component extracting section 55, the total filter characteristic on the inner circumference side of the disk is obtained by the gain and frequency shown in FIG. The filter characteristic has the relationship between the phase and the frequency shown in FIG. 9. The overall filter characteristic on the outer peripheral side of the disk has the relationship between the gain and the frequency shown in FIG. 9A and the phase and the frequency shown in FIG. 9B. It becomes filter characteristics, and by these, it becomes possible to extract the frequency component of surface runout with higher accuracy, and as a result,
The degree of improvement of the surface vibration frequency component in the subsequent focus servo is increased.

The signal after phase compensation by analog filtering by the above-mentioned phase compensator 51 is added to the adder 5.
2 and the surface vibration frequency component extracted by the surface vibration component extraction unit 55 by the analog filtering process is transmitted to the switch 56.

The switch 56 is basically the same as the switch 21 of the first embodiment shown in FIG.
On / off control is performed by an output enable signal EN1 supplied from the controller 8 of FIG.

The adder 52 adds the surface vibration frequency component via the switch 56 to the analog waveform signal after the phase compensation by the phase compensator 51. In the adder 52, the analog waveform signal to which the surface vibration frequency component has been added is sent to the drive circuit 53 thereafter.

The drive circuit 53 is the same as the drive circuit 18 of the first embodiment shown in FIG.
The analog waveform signal supplied from the adder 52 is output as a focus drive signal FD for driving the focus actuator section in the focus direction. This focus drive signal FD is sent from the terminal 54 to the actuator (focus actuator unit) of the optical head 2 in FIG.

In the focus control section 7 of the second embodiment shown in FIG. 4, as in the case of the above-described first embodiment, the focus error signal is phase-compensated with the signal. By generating the focus drive signal FD from the signal obtained by adding the maximum amplitude of the surface vibration frequency component among the surface vibration frequency components of the disk, even if the recording / reproducing position of the optical disk 1 moves and the rotation frequency changes. ,
It is possible to realize a focus servo that follows the surface deflection of the optical disc 1.

Next, FIG. 10 shows a surface shake component extraction unit 55 of the focus control unit 7 according to the second embodiment shown in FIG.
The following shows a specific configuration example.

In FIG. 10, a terminal 60 is
The focus error signal FE is supplied from the signal generation unit 4 of FIG. The focus error signal FE input to the terminal 60 is sent to the anti-aliasing filter 61.

This anti-aliasing filter 61
It has the same function as the anti-aliasing filter 11 of FIG. 2 and removes so-called aliasing noise from the focus error signal FE. That is, the anti-aliasing filter 61 limits the band of the focus error signal to a frequency equal to or less than half the sampling frequency SP2 of the digital filter (surface shake component extraction filter). The focus error signal passed through the anti-aliasing filter 61 is digitized by the A / D conversion circuit 72a and sent to the switch 62.

The switch 62 is the switch 34 shown in FIG.
The switch has basically the same function as that of the first embodiment, and is turned on / off by a sampling pulse SP2 supplied from a sampling pulse generator 23 via a terminal 71. That is, the switch 62 is turned on / off by the sampling pulse SP2 corresponding to the RF signal, thereby discretely cutting out the focus error signal via the anti-aliasing filter 61. The discrete signal cut by the switch 62 is sent to the surface runout component extraction filter 63.

The surface runout component extraction filter 63 is provided in FIG.
Performs basically the same operation as the surface shake component extraction filter 35, and is constituted by an analog filter.
The surface vibration component extraction filter 63 has digital filter characteristics set by a configuration from a maximum value detection unit 67 to a surface vibration frequency determination unit 70, which will be described later, and extracts a surface vibration frequency component from a signal from the switch 62 in the preceding stage. It is a filter for. The surface vibration frequency component output from the surface vibration component extraction filter 63 is output to the D / A conversion circuit 72b.
, And is sent to the surface shake component extraction filter output storage unit 64.

The surface runout component extraction filter output storage unit 6
The surface vibration frequency component once stored at 4 is read out thereafter, and is supplied to a terminal 66 via a smoothing filter 65 having the same function as the smoothing filter 17 of FIG.
Is sent to the optical head 2 of FIG. 1 as a focus drive signal FD, and is also sent to the maximum amplitude detector 67.

Here, the basic operation of the surface shake component extraction filter 63 in the case of the example of FIG. 10 is set in the same manner as in the example of FIG. That is, the detection frequency of the surface deflection component extraction filter 35 is sequentially set to each frequency of 1, 2, 3, 4,..., N times the disk rotation frequency. The maximum amplitude detecting section 67 detects the maximum amplitude value of the supplied signal for each of the sequentially set detection frequencies.

The maximum amplitude values sequentially detected by the maximum amplitude detection section 38 are alternately stored in the maximum amplitude value storage section 6.
After being stored in 8 and 69, it is read out and sent to the surface runout frequency determination unit 70. The plane runout frequency determination unit 70 sequentially compares the magnitudes of the maximum amplitude values of the respective supplied disk rotation frequencies, and stores the comparison results. Then, the disk rotation frequency n
When the comparison result of the maximum amplitude values up to the double is completed, the surface vibration frequency determination unit 70 selects a frequency having the largest maximum amplitude value from the comparison results, determines the frequency as the surface vibration frequency, and further determines the frequency. When the frequency is determined, a filter characteristic for extracting the component of the determined surface vibration frequency is set and supplied to the surface vibration component extraction filter 63. As a result, the surface vibration component extraction filter 63 extracts only the surface vibration frequency component having the largest amplitude value from the signal of the switch 62 in the preceding stage.

Next, FIG. 11 shows a specific configuration example of the focus control unit 7 in the case of the third embodiment of the present invention. In FIG. 11, both the phase compensation in the focus system and the extraction of the surface vibration frequency component of the disc are realized by a digital circuit, and the focus error signal (the focus error signal after the phase compensation) is obtained from the disc bowl. This is a configuration example in a case where a configuration (digital circuit) for extracting an offset component due to a mold warp is provided. In FIG. 11, the same components as those of the focus control unit 7 of the first embodiment shown in FIG. 2 described above are denoted by the same reference numerals, and the description thereof will be omitted. The following description focuses on the configuration different from 2.

In FIG. 11, the digital signal after phase compensation by the phase compensating section 14 is sent to the adder 80 and also sent to the bowl-shaped warp extracting section 81.

The bowl-shaped warp extraction unit 81 extracts and averages an offset component generated when the disc is bent into a bowl shape from the focus error signal after the phase compensation by the phase compensation unit 14, and averages the offset components. , Terminal 93
Based on the calculation result storage enable signal SE supplied from the controller 8 of FIG. 1 through the above, the average value is sequentially cumulatively added (or subtracted) and stored, and the cumulatively added (or subtracted) average value is calculated as It is extracted as an offset component to be added to the focus error signal after the phase compensation. That is, the bowl-shaped warp extraction unit 81 extracts, from the bowl-shaped warp-shaped optical disc 1, an offset component that changes according to the position in the disc radial direction and has substantially the same amount on the same circumference. It is. The specific configuration and operation of the bowl-shaped warp extraction unit 81 will be described later. The output signal from the bowl-shaped warp extraction unit 81 is sent to the switch 82.

The switch 82 has an output enable signal EN supplied from the controller 8 of FIG.
The output of the switch 82 is sent to the adder 80. That is, the switch 82 is controlled by the output enable signal EN2 having the same selection function as that of the above-described output enable signal EN1 from the controller 8 (in this case, the function of selecting an offset component due to a bowl-shaped warp). Switching means for selectively switching whether or not to add an offset component due to bowl-shaped warping to the digital focus error signal.

In the adder 80, the surface vibration frequency component via the switch 21 (the surface vibration frequency component determined to be added by the output enable signal EN1 of the controller 8) to the digital signal after phase compensation by the phase compensator 14 ) And the offset component of the bowl-shaped warpage via the switch 82 (the offset component of the bowl-shaped warpage determined to be added by the output enable signal EN2 of the controller 8). In the third embodiment, the adder 80 selectively adds the offset component of the bowl-shaped warp and the surface vibration frequency component to a digital signal,
/ A converter 16.

As described above, in the focus control section 7 of the third embodiment shown in FIG. 11, the signal after phase compensation is applied to the focus error signal, By generating the focus drive signal FD from the signal obtained by selectively adding the offset component of the warp, even if the recording / reproducing position of the optical disc 1 moves and the rotation frequency changes, the focus drive signal FD can only follow the surface runout of the optical disc 1. In addition, it is possible to realize a focus servo that can cope with an offset due to bowl-shaped warpage.

Next, FIG. 12 shows a specific configuration example of the bowl-shaped warp component extraction section 81 of the focus control section 7 of the third embodiment shown in FIG.

In FIG. 12, a terminal 90 is
The focus error signal phase-compensated by the first phase compensator 14 is supplied. The focus error signal after phase compensation input to the terminal 90 is sent to the average value calculation unit 91.

The average value calculation section 91 is composed of, for example, a low-pass filter, extracts an offset component from the supplied focus error signal after phase compensation, and outputs the average value. That is, when bowl-shaped warpage occurs in the optical disc 1, the offset components on the same radius of the disc are considered to be substantially the same.
Only the offset component is extracted and output. The average value from the average value calculation unit 91 is output via a terminal 93 to FIG.
Is sent to an average value storage unit 94 via a switch 92 that is turned on / off in response to a calculation result storage enable signal SE supplied from the controller 8 of the storage unit.

In the average value storage section 94, the average value is cumulatively added (or subtracted) and stored for each calculation result storage enable signal SE. The stored average value is then taken out and output from the terminal 95 as an offset component of the bowl-shaped warp extracted from the focus error signal after phase compensation by the bowl-shaped warp extraction unit 81. In the mean value storage unit 94, the calculation result storage enable signal S
The cumulative addition (or subtraction) of the average value according to E
When the optical disc 1 is bowl-shaped, the warp is, for example, a warp in which the outer circumference is lowered (or raised) with respect to the center of the optical disc, and therefore, the offset of the focus error signal (focus error signal after phase compensation). The component also changes depending on the position in the radial direction of the disk, so that it is possible to cope with a change in the offset component due to such bowl-shaped warpage. Further, the calculation result storage enable signal SE is generated by the controller 8 in order to realize addition (or subtraction) of the offset component (average value) according to the radial position of the optical disc 1 as described above.

Next, FIG. 13 shows a specific configuration example of the focus control section 7 in the case of the fourth embodiment of the present invention. In FIG. 13, both the phase compensation of the focus system and the extraction of the surface vibration frequency component of the disk are realized by an analog circuit, and the offset component due to the bowl-shaped warpage of the disk is extracted from the focus error signal. 1 is a configuration example in a case where a configuration (analog circuit) for performing the operation is provided. In FIG. 13, the same components as those of the focus control unit 7 according to the second embodiment shown in FIG. 4 described above are denoted by the same reference numerals, and the description thereof will be omitted. The following description focuses on the configuration different from that of FIG.

In FIG. 13, the analog waveform signal of the focus error signal after the phase compensation by the phase compensating section 51 is sent to the adder 103 and also to the bowl-shaped warp extracting section 100.

The bowl-shaped warp extracting section 100 extracts the average value of the offset component from the focus error signal after the phase compensation by the phase compensating section 51, and is supplied from the controller 8 of FIG. The average value is stored while being added (or subtracted) according to the calculation result storage enable signal SE, and the average value is extracted as an offset component to be added to the focus error signal after the phase compensation. The specific configuration and operation of the bowl-shaped warp extraction unit 100 will be described later. The output signal from the bowl-shaped warp extraction unit 100 is sent to the switch 102.

The switch 102 is on / off controlled by an output enable signal EN2 supplied from the controller 8 of FIG. 1 through a terminal 101. The output of the switch 102 is sent to an adder 103. That is, the switch 102 is switching means for selectively switching whether or not to add an offset component due to a bowl-shaped warp to the analog signal after the phase compensation according to the output enable signal EN2 from the controller 8.

In the adder 103, the surface vibration frequency component via the switch 56 (the surface vibration determined to be added by the output enable signal EN1 of the controller 8) to the analog focus error signal after the phase compensation by the phase compensator 51. The frequency component) and the offset component of the bowl-shaped warpage via the switch 102 (the offset component of the bowl-shaped warpage determined to be added by the output enable signal EN2 of the controller 8) are added. In the fourth embodiment, an analog focus error signal to which the offset component of the bowl-shaped warpage and the surface vibration frequency component are selectively added by the adder 103 is sent to the drive circuit 53.

As described above, in the focus control unit 7 of the fourth embodiment shown in FIG. 13, the signal obtained by performing phase compensation on the focus error signal includes By generating the focus drive signal FD from the signal obtained by selectively adding the offset component of the warp, even if the recording / reproducing position of the optical disc 1 moves and the rotation frequency changes, the focus drive signal FD can only follow the surface runout of the optical disc 1. In addition, it is possible to realize a focus servo that can cope with an offset due to bowl-shaped warpage.

Next, FIG. 14 shows a specific configuration example of the bowl-shaped warp component extraction unit 100 of the focus control unit 7 of the fourth embodiment shown in FIG.

In FIG. 14, an analog focus error signal phase-compensated by the phase compensator 51 of FIG. 13 is supplied to a terminal 110. The focus error signal input to the terminal 110 is sent to the average value calculator 111.

The average value calculation section 111 is composed of, for example, a low-pass filter, and calculates and outputs an average value of offset components from the supplied focus error signal after phase compensation. The average value from the average value calculation unit 111 is
1 through a switch 112 which is turned on / off in response to a calculation result storage enable signal SE supplied from the controller 8 in FIG.

The sample-and-hold unit 113 samples and holds the input signal and stores the average value. The sample-and-hold average value is thereafter taken out, and the bowl-shaped warp extraction unit 100 focuses on the signal. It is output from the terminal 114 as an offset component of the bowl-shaped warp extracted from the error signal. That is, in the case of the fourth embodiment, the average value sampled and held corresponds to the offset component.

In the above-described first to fourth embodiments, when any external vibration or impact is applied to the optical disk recording / reproducing apparatus at the time of recording / reproducing the disk, for example, the frequency component of the above-mentioned surface vibration is obtained. There is a possibility that the detected value of the offset component changes.

For this reason, the controller 8 shown in FIG. 1 detects, for example, a sudden change in the focus error signal FE, a sudden change in the tracking error signal (not shown), or a shock from a shock detecting means such as an acceleration sensor (not shown). When a shock is detected by a signal, etc., control is performed so that the frequency component or offset component of the surface vibration is not added to the focus error signal after phase compensation, so that the surface vibration frequency component or the offset component due to external vibration or shock The influence on the focus servo due to the change in the detection value of the is suppressed.

More specifically, the controller 8 controls the switches 21 and 56 by the enable signals EN1 and EN2.
Is turned off (opened), so that the frequency component and the offset component of the surface vibration are not added to the focus error signal after the phase compensation, and the surface vibration frequency component and the Offset component
The surface vibration component extraction filter output storage units 36 and 64, the average value storage unit 94, the sample hold unit 113, and the like are held, and after the influence of the impact is eliminated, the held surface vibration frequency components and offset components are used. Control to restart the focus servo.

Further, in each of the first to fourth embodiments described above, the optical disk 1 is described as an example of an optical disk having only one recording layer, for example.
The fourth to fourth embodiments are also applicable to a multilayer disc having a plurality of recording layers.

Here, when a multilayer disc is used as the optical disc 1, for example, a layer switching acceleration pulse or a layer switching deceleration pulse is calculated and given with reference to an offset component corresponding to a bowl-shaped warpage of the disk. It is possible to switch the disk layer with higher accuracy.
Further, when a multilayer disc is used as the optical disc 1, for example, a layer switching acceleration pulse or a layer switching acceleration pulse is determined based on a value obtained by adding an offset component value corresponding to a bowl-shaped displacement and a frequency component of a plane runout at the time of layer switching. By calculating and applying the layer switching deceleration pulse, the disk layer can be switched with higher accuracy.

Further, in each of the above-described embodiments, an example is described in which the initial value of the filter is set as the initial state in the surface shake component extraction unit. Is operated, and after the filter is stabilized, the surface vibration frequency component is added to the focus error signal after the phase compensation, so that it is not necessary to set the initial value of the filter.

The method for extracting the frequency components of twice, three times,... The rotation frequency of the optical disc 1 in the surface vibration component extraction unit is as described in each of the above embodiments. In addition to the method, for example, the sampling frequency can be doubled, tripled, and changed without changing the rotation speed of the optical disc 1.
(Double the sampling period, 1/2, 1 /
3, 1/4,...).

That is, for example, the rotation speed of the optical disc 1 is detected, and the above-described double, three,
.., A sampling pulse having a frequency of × 4,... May be generated, and the filter may be operated using the sampling pulse. More specifically, for example, when a pseudo sampling pulse is generated by a multiplying frequency generator or the like and a filter coefficient that extracts a frequency component that is one time the disk rotation frequency is used, the disk is rotated,
It is measured by counting the rising cycle of the FG signal, or the rising and falling cycles, using a master clock.
1/3, 1/4,..., And a plurality of count values corresponding to the sampling periods of 1, 1/2, 1/3, 1/4,. .. Are stored in a memory (for example, memories M1, M2, M3, M4,...). The master clock is counted by the count of the memory M1 to generate a sampling pulse. When a double frequency component is extracted, the master clock is counted by the count of the memory M2 to generate a sampling pulse. The same applies to the following. When extracting a triple frequency component, the master clock is counted by the count of the memory M3 to generate a sampling pulse, and a quadruple frequency component is extracted. Do things like generate sampling pulses by counting the master clock is counted the number of the memory M4.

Furthermore, instead of using the FG signal from the FG signal generator of the spindle motor 6 as a timing signal for quantization or the like as in each of the above-described embodiments,
A similar result can be obtained by obtaining the FG signal of the spindle motor corresponding to any radial position on the optical disc 1 and using it as a timing signal.

As described above, according to each of the embodiments of the present invention, the rotation of the optical disc 1 in accordance with the radius of the reproduction or recording position so that the linear velocity is constant or changes stepwise depending on the area. In a disk recording / reproducing apparatus that changes the speed, it is possible to change the filter coefficient without changing the filter coefficient during reproduction of the optical disk 1 and to change the optimum filter characteristic depending on the disk radial position. Can be optimally changed, and
These processes can be executed during a short calculation time with a limited time, and therefore, a highly accurate focus servo that reduces the residual deviation of the disk runout and takes into account the offset component due to the bowl-shaped warpage of the disk Is possible.

Further, according to each embodiment of the present invention, since the offset value of the focus drive signal which varies depending on the radial position of the disk is always calculated, for example, the reference value of the layer switching control of the multilayer disk can be accurately obtained. Therefore, layer switching can be performed with high accuracy.

The present invention is not limited to the above-described embodiment, and various changes can be made according to the design and the like without departing from the technical idea of the present invention.

[0123]

According to the disk drive according to the first aspect of the present invention and the head driving method of the disk drive according to the third aspect of the present invention, a rotational deviation component is calculated for a position error after phase compensation. By using the addition output formed by the selective addition as the drive signal of the head drive means, for example, when reproducing various discs, and when the disc is warped, for example, when there is a warp due to the disc pressing, In addition, it is possible to eliminate the defocus at the time of focusing and to optimize the quality of the recorded or reproduced signal.

According to a second aspect of the present invention, an offset component due to a warp of a disk medium is detected from a position error after phase compensation, and the adding unit rotates the offset component with respect to the position error after phase compensation. Focusing is achieved by selectively adding the deviation component and the offset component, for example, when playing various discs, and when there is a bowl-shaped warpage as well as a warpage due to disc holding. The quality of the recording or reproduction signal can be optimized by eliminating the defocusing at the time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration (particularly, a signal reproducing system and a focus servo system) of an optical disk recording / reproducing apparatus according to an embodiment to which a disk device of the present invention is applied.

FIG. 2 is a block diagram showing a specific configuration example of a focus control unit in a case where both phase compensation of a focus system and extraction of a surface vibration frequency component of a disk are realized by a digital circuit as a first embodiment of the present invention; FIG.

FIG. 3 is a block diagram illustrating a specific configuration example of a surface shake component extraction unit of the focus control unit according to the first embodiment.

FIG. 4 shows, as a second embodiment of the present invention, a specific configuration example of a focus control unit 7 in a case where both phase compensation of a focus system and extraction of a surface vibration frequency component of a disk are realized by an analog circuit. It is a block diagram.

FIG. 5 is a characteristic diagram illustrating an example of a filter characteristic of a phase compensation unit of the focus control unit according to the second embodiment.

FIG. 6 is a characteristic diagram illustrating a filter characteristic (particularly, a filter characteristic on an innermost peripheral side of a disc) of a surface shake component extraction unit of a focus control unit according to the second embodiment.

FIG. 7 is a characteristic diagram showing a filter characteristic (particularly, a filter characteristic on the outermost peripheral side of a disk) of a surface shake component extraction unit of a focus control unit according to the second embodiment.

FIG. 8 is a characteristic diagram showing a total filter characteristic (particularly, a total filter characteristic on the innermost peripheral side of a disk) of a phase compensation unit and a surface shake component extraction unit of a focus control unit according to the second embodiment.

FIG. 9 is a characteristic diagram illustrating a total filter characteristic (particularly, a total filter characteristic on the outermost peripheral side of a disk) of a phase compensation unit and a surface shake component extraction unit of the focus control unit according to the second embodiment.

FIG. 10 is a block diagram illustrating a specific configuration example of a surface shake component extraction unit of a focus control unit according to the second embodiment.

FIG. 11 shows a third embodiment of the present invention in which the phase compensation of the focus system, the extraction of the surface vibration frequency component of the disk, and the extraction of the offset component of the bowl-shaped warp are both realized by a digital circuit. FIG. 3 is a block diagram illustrating a specific configuration example of a control unit.

FIG. 12 is a block diagram illustrating a specific configuration example of a bowl-shaped warp extraction unit of the focus control unit according to the third embodiment.

FIG. 13 shows a fourth embodiment of the present invention in which the phase compensation of the focus system, the extraction of the surface vibration frequency component of the disc, and the extraction of the offset component of the bowl-shaped warp are both realized by an analog circuit. FIG. 3 is a block diagram illustrating a specific configuration example of a control unit.

FIG. 14 is a block diagram illustrating a specific configuration example of a bowl-shaped warp extraction unit of the focus control unit according to the fourth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Optical head (optical pickup), 3
... 4-division photodiode, 4 ... signal generation unit, 6 ... spindle motor, 7 ... focus control unit, 8 ... controller, 11, 61 ... anti-aliasing filter, 12,
21, 31, 34, 56, 62, 82, 92, 102,
112: switch, 13: A / D converter, 14, 5
1: phase compensator, 15, 52, 80, 103 ... adder,
16: D / A converter, 17, 65: smoothing filter, 18, 53: drive circuit, 20, 55: surface vibration component extraction unit, 22: sampling pulse SP1 generation unit, 23: sampling pulse SP2 generation unit, 32: sub Sampling filter, 33: sub-sampling filter output storage unit, 35, 63: surface runout component extraction filter, 36, 64 ... surface runout component extraction filter output storage unit,
38, 67... Maximum amplitude detector, 39, 40, 68, 69
... Maximum amplitude value storage unit, 41,70 Surface runout frequency determination unit, 81,100 ... Bowl-shaped warp extraction unit, 91,111 ...
Average value calculation unit, 94: Average value storage unit, 113: Sample hold unit

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) KK54

Claims (3)

[Claims] 1. A position error detection unit for detecting a position error of a head with respect to a disk medium; a rotation drive unit for driving the disk medium to rotate; a head drive unit for driving the head in a focus direction; A rotation deviation component detection unit that detects a deviation component of a rotation frequency or a frequency that is an integral multiple of the rotation frequency, a phase compensation unit that performs phase compensation of a position error detected by the position error detection unit, and a phase compensation unit that performs phase compensation by the phase compensation unit. For the position error of
An adder for selectively adding the rotational deviation component detected by the rotational deviation component detector, wherein an output signal of the adder is supplied as a drive signal of the head driver. 2. An offset component detecting unit for detecting an offset component due to warpage of the disk medium from a position error after the phase compensation by the phase compensating unit. 2. The disk device according to claim 1, wherein the rotation error component detected by the rotation error component detection means and the offset component detected by the offset component detection means are selectively added to the position error. Detecting a position error of the head with respect to the disk medium, detecting a deviation component of the rotational frequency of the disk medium or a frequency that is an integral multiple thereof, and compensating for the phase error of the position error detected by the step. Performing the step of: selectively adding the rotational deviation component detected in the step to the position error after the phase compensation in the step; and supplying the added output in the step as a drive signal for the head. And a head driving method for a disk drive.