JP2002298394A - Disk drive device and information reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk drive device and an information reading method capable of realizing proper servo control of a reading means in information reading from a recording medium in which a land and a groove are formed. SOLUTION: The disk drive device is provided with a tracking error signal generating means to generate a tracking error signal TE to indicate deviation of a scanning position of the reading means, a TE average compensation register 51 and a re-compensation register 53 to compensate the tracking error signal TE, an inversion circuit 55 to invert the compensated signal and to generate a tracking error inversion signal, a detecting means to detect which of the land and the groove the reading means is scanning and a driving means to select either of the tracking error signal TE or the tracking signal inversion signal according to a detection result by the detecting means and to perform tracking control of the reading means by the selected signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive for recording and reproducing information on a disk-shaped recording medium, and to an information reading method.

[0002]

2. Description of the Related Art Conventional compact disks (CD) and D
A VD-ROM or the like is an optical disk employing a pit recording method. By scanning an optical pickup along a track on which the pits are formed and measuring reflected light,
The information recorded by the pits is reproduced. here,
Conventionally, a tracking error signal having the same polarity is always generated in accordance with the amount of deviation of the optical pickup from the track. Therefore, this signal is used as it is for tracking servo control (hereinafter, also simply referred to as “tracking control”). It was used for.

However, when information is read from an optical disk such as a DVD-RAM on which lands and grooves (grooves) are formed, the polarity of the tracking error signal is inverted depending on whether the read destination is a land or a groove. Therefore, there is a problem that the tracking error signal cannot be directly used for tracking control.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made in the art of DVD-RAM.
It is an object of the present invention to provide a disk drive device and an information reading method capable of realizing proper servo control of a reading unit in reading information from a recording medium on which lands and grooves are formed.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a disk drive device for reading information from a recording medium having lands and grooves formed thereon and information recorded on the lands and grooves by a reading means, comprising a correcting means. Inverting means for inverting the corrected tracking error signal to generate a tracking error inverted signal, and a tracking error signal or the above tracking error inverted signal depending on whether the area scanned by the reading means is a land or a groove. This is achieved by providing a disk drive device including a drive unit that selects any one of them and performs tracking control on the reading unit based on the selected signal.

According to such a means, the driving means executes the tracking control based on the tracking error signal corrected by the correcting means and its inverted signal, so that the scanning of the reading means can be controlled more accurately. Note that “tracking control” refers to controlling the position of the recording medium in the radial direction with respect to scanning by the reading unit. Here, the correction unit corrects the tracking error signal in accordance with a difference between an average value of the tracking error signal obtained when the reading unit reads information from the recording medium in an optimal state and the initially set average value. Things. The “optimal state” described above refers to a state where the optical disc is placed at a position close to the recording medium and the light reflected by the recording medium is reliably detected. According to such a means, it is possible to realize tracking control based on an optimal tracking error signal.

It is another object of the present invention to provide an information reading method for reading information from a recording medium on which information is recorded in which lands and grooves are formed, wherein the corrected tracking error signal is inverted to obtain a tracking error inverted signal. And the step of detecting which of the lands or grooves the scanning means is scanning, and selecting either the tracking error signal or the tracking error inversion signal according to the detection result, and using the selected signal And tracking control of the reading means.
According to such means, the accuracy of tracking control for scanning by the reading means can be easily increased.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts. FIG. 1 is a block diagram showing an overall configuration of a disk drive device according to an embodiment of the present invention. As shown in FIG. 1, the disk drive device according to the present embodiment is a device for recording and reproducing information on and from an optical disk 1 mounted thereon, and includes a spindle motor (SPM) 2 and an optical pickup 3. , Two-axis mechanism 3a, RF amplifier 4, servo processor 5, drive circuit 6, binarization circuit 7, clock reproduction circuit 8,
A decoding circuit 9, an error correction circuit 10, a buffer memory 11, a data interface 12, a system controller 13, a RAM block 14, a header detection unit 15,
The host computer 4 includes a PID detector 16, a land / groove detector 17, an external data bus 18, a thread mechanism 19, a laser diode 30, an objective lens 34, and a photodetector 37.
0.

In the above, the spindle motor (SP
M) 2 controls the rotation of the turntable on which the optical disc 1 is mounted. The optical pickup 3 irradiates a laser beam to the signal surface of the optical disk 1 by the laser diode 30 and detects reflected light from the signal surface by the photodetector 37, thereby obtaining the optical disk 1.
Of the data recorded in the. Here, the objective lens 34 constituting the optical pickup 3 condenses the laser beam emitted from the laser diode 30 and irradiates the laser beam onto the signal surface of the optical disk 1. The objective lens 34 is moved in the tracking direction by the biaxial mechanism 3a. And movably held in the focus direction. The optical pickup 3 is moved by the thread mechanism 19 to the optical disc 1.
Is movable in the radial direction.

The reflected light detected by the optical pickup 3 is supplied to an RF amplifier 4 as a current signal corresponding to the amount of the reflected light, and the RF amplifier 4 performs current / voltage conversion and matrix calculation processing. Is performed to generate a focus error signal FE and a tracking error signal TE. Further, an RF signal as reproduction information, a PI (pull-in) signal as a sum signal, and the like are generated.

The focus error signal FE and the tracking error signal TE generated by the RF amplifier 4 are supplied to a drive circuit 6 after required processes such as phase compensation and gain adjustment are performed by a servo processor 5. More specifically, the servo processor 5 generates a thread control signal SS for track jump via a built-in low-pass filter (LPF) and supplies it to the drive circuit 6, and focuses in response to an instruction from the system controller 13. A signal SF for a search operation and a signal ST for a track jump operation are supplied to the drive circuit 6. Here, the drive circuit 6 executes the thread servo control by outputting the thread control signal SS for track jump to the thread mechanism 19 as a thread drive signal, and generates a focus drive signal and a tracking drive signal to generate a two-axis mechanism. The focus servo control and the tracking servo control are executed by outputting the signal to 3a. Thereby, focus search, track jump / access, and the like of the optical pickup 3 are realized.

On the other hand, the reproduced RF signal generated by the RF amplifier 4 is binarized by a binarization circuit 7 and is subjected to EFM.
A plus signal is generated. Then, the EFM plus signal is supplied to the clock recovery circuit 8, and a recovered clock signal CLK synchronized with the EFM plus signal is extracted and generated.
The reproduced clock signal CLK is supplied as an operation clock in various circuits including the decode circuit and the servo processor 5.

The EFM plus signal from which the clock signal has been extracted as described above is supplied to a decoding circuit 9 and demodulated, and then supplied to an error correction circuit 10. The error correction circuit 10 performs an error correction process according to, for example, the RS-PC method while using the buffer memory 11 as a work area. The error-corrected binarized data is transferred to the data interface 12. The data interface 12 is provided for communication with an external information processing device such as a host computer 40 connected via the external data bus 18, and has the binary data ( (Reproduced data) to the host computer 40.

The system controller 13 controls the entire disk drive and is constituted by a microcomputer. The system controller 13 controls the operation of each unit based on the operation status, instructions from the host computer 40, and the like.

Further, a RAM block 14 is provided corresponding to the reproduction of the DVD-RAM. Where RA
The header detector 15 included in the M block 14 detects the timing at which the trace position of the laser beam passes through the header area of the DVD-RAM. Further, the PID detection unit 16 detects a physical address PID recorded in the header area.

In reproducing information recorded on a DVD-RAM, it is detected whether a recording area of a sector to be read is formed on a land or a groove, and according to the detection result, It is necessary to invert the polarity of the tracking error signal TE used in the tracking servo control. Here, the land / groove detection unit 17 detects whether the read target area is a land or a groove, and outputs a signal S indicating a determination result.
Generate and output LG. Note that the push / pull signal PP generated in, for example, the RF amplifier 4 is supplied to the land / groove detection unit 17.

FIG. 2 is a diagram showing a configuration of the tracking error correction circuit 50 included in the servo processor 5 shown in FIG. As shown in FIG. 2, the tracking error correction circuit 50 includes a TE average correction register 51, adders 52 and 54, a re-correction register 53, and an inversion circuit 5.
5, a register 56, a tracking filter 57, and switch circuits SW1 to SW3.

Here, the tracking error signal TE from the RF amplifier 4 is supplied to the TE average correction register 51 and the adder 52.
Is supplied. A switch circuit SW1 is connected between the output node of the TE average correction register 51 and the adder 52. The output node of the adder 52 is connected to the input node of the re-correction register 53 and the adder 54, and a switch circuit SW2 is connected between the output node of the re-correction register 53 and the adder 54.

An inverting circuit 55 is connected to the output node of the adder 54, and the signal generated by the adder 54 or the signal inverted by the inverting circuit 55 is selectively supplied to the register 56 by the switch circuit SW3. Is done. A tracking filter 57 is connected to the register 56,
The output node of the tracking filter 57 is connected to the drive circuit 6.

The switch circuit SW1 is controlled by a control signal TLC1 supplied from the system controller 13.
The switching operation of the switch circuit SW2 is controlled by the control signal TLC2 supplied from the system controller 13, and the switching operation of the switch circuit SW3 is controlled by the signal SLG supplied from the land / groove detection unit 17.

The tracking error correction circuit 50 having the above-described configuration is a circuit for performing a correction process on the tracking error signal TE. Hereinafter, each component of the circuit will be described.

The TE average correction register 51 samples the tracking error signal TE supplied from the RF amplifier 4 at a predetermined cycle, finds an average value of the signal, and calculates a deviation from the set average value. Then, the shift (DC offset) is canceled by the adder 52. That is, for example, when the ideal waveform of the tracking error signal TE is indicated by the waveform 60 in FIG. 3A and the signal indicated by the waveform 59 is obtained in the TE average correction register 51, the actually measured tracking error signal TE
The value L1 is obtained as the average value of. And the adder 52
As a result, the value L1 is subtracted from the original tracking error signal TE, and the deviation of the average value is canceled. Note that the above-described correction by the TE average correction register 51 is executed in a state where the optical pickup 3 is placed below a position where optimum information reproduction is realized in FIG.

The re-correction register 53 extracts a low frequency component in the waveform 61 of the tracking error signal TE supplied from the adder 52 by using a built-in track hold filter. The amount of deviation of the average value of the components from the value L1 is calculated. Then, the shift amount is subtracted from the tracking error signal TE by the adder 54, and the tracking error signal TE is corrected. The above-described correction by the re-correction register 53 is executed in a state where the optical pickup 3 is placed at a position where the optimum information reproduction is realized in FIG.

Accordingly, by correcting the tracking error signal TE supplied from the RF amplifier 4 by the TE average correction register 51 and the re-correction register 53, an optimum tracking error signal TE is generated. And
This optimum tracking error signal TE having the waveform 61 shown in FIG. 3A is supplied to the switch circuit SW3 as it is, and is inverted by the inverting circuit 55 to change the waveform 62 shown in FIG. The inverted tracking error signal is supplied to the switch circuit SW3.

Here, lands and grooves are formed,
When reproducing the optical disk 1 such as a DVD-RAM or the like in which information is recorded in both of these portions, the information is obtained when the optical pickup 3 scans a land and when it scans a groove. The polarity of the tracking error signal TE is inverted. Therefore, the switch circuit SW
In 3, the tracking error signal TE or the tracking error inversion signal is selected according to the signal SLG supplied from the land / groove detecting unit 17 and supplied to the register 56. That is, the optical pickup 3
Is scanning the land of the optical disk 1, a signal SLG indicating that the scanning area is a land is supplied from the land / groove detecting unit 17 to the switch circuit SW3, and the waveform 61 shown in FIG. Is supplied to the register 56. on the other hand,
When the optical pickup 3 scans the groove of the optical disk 1, a signal SLG indicating that the scanning area is a groove is supplied from the land / groove detecting unit 17 to the switch circuit SW3, and the waveform shown in FIG. A tracking error inversion signal having 62 is supplied to the register 56.

The register 56 stores the supplied tracking error signal TE and tracking error inverted signal, and supplies these signals to the tracking filter 57. Note that the tracking filter 57 is
The signal S is filtered by filtering the supplied signal.
T is generated, and the signal ST is supplied to the drive circuit 6.

As described above, according to the disk drive device of the embodiment of the present invention, the TE average correction register 51
The inverted signal is generated based on the optimum tracking error signal TE obtained by performing the correction by the re-correction register 53, and the optimum tracking error signal TE and the inverted signal are stored in the scanning area of the optical pickup 3. , It is possible to realize highly accurate tracking control.

It should be noted that the disk drive device according to the present embodiment switches the reproduction signal processing system according to the type of the recording medium, or changes the required reproduction parameters, etc. -RO
M, or CD-DA (Digital Audio), CD-R
The present invention can be realized as an apparatus for reproducing a recording medium such as an OM.

[0029]

According to the disk drive of the present invention, the tracking control is executed in accordance with the tracking error signal corrected by the correction means and the inverted signal thereof, whereby the scanning by the reading means is controlled with high accuracy. Therefore, the reproduction accuracy of information can be improved. Here, the correction unit corrects the tracking error signal in accordance with a difference between an average value of the tracking error signal obtained when the reading unit reads information from the recording medium in an optimal state and the initially set average value. If this is the case, the tracking control based on the optimal tracking error signal can be realized, so that the information reproduction accuracy can be further improved. Further, according to the information reading method of the present invention, it is possible to improve the accuracy of tracking control for the reading unit, thereby easily improving the reliability in information reproduction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a disk drive device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a tracking error correction circuit included in the servo processor shown in FIG.

FIG. 3 is a waveform diagram illustrating an operation of the tracking error correction circuit shown in FIG.

[Explanation of symbols]

1 optical disk, 2 spindle motor (SPM),
Reference Signs List 3 optical pickup, 3a biaxial mechanism, 4 RF amplifier, 5 servo processor, 6 drive circuit, 7 binarization circuit, 8 clock reproduction circuit, 9 decoding circuit, 10
Error correction circuit, 11 buffer memory, 12 data interface, 13 system controller, 14
RAM block, 15 header detector, 16 PI
D detector, 17 land / groove detector, 18 external data bus, 19 thread mechanism, 30 laser diode, 34 objective lens, 37 photodetector, 4
0 host computer, 50 tracking error correction circuit, 51 TE average correction register, 52, 54 adder, 53 re-correction register, 55 inversion circuit, 56
Register, 57 tracking filter, SW1-SW
3 Switch circuit.

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[Procedure amendment]

[Submission date] April 17, 2001 (2001.4.1
7)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuyuki Hayashi 134 Kobe-cho, Hodogaya-ku, Yokohama-shi, Kanagawa Prefecture Sony LSI Design Inc. F-term (reference) 5D118 AA13 BC09 CA07 CA13 CD03 CD11

Claims (3)

[Claims] 1. A disk drive device in which lands and grooves are formed and information is read by a reading unit from a recording medium on which information is recorded on the lands and grooves, the disk drive device indicating a shift of a scanning position of the reading unit. Tracking error signal generating means for generating a tracking error signal; correcting means for correcting the tracking error signal; inverting means for inverting the signal corrected by the correcting means to generate a tracking error inverted signal; Detecting means for detecting which of the land and the groove is scanning, and, according to a detection result by the detecting means, selects either the tracking error signal or the tracking error inversion signal, and the selected signal Driving means for performing tracking control of the reading means by means of Disk drive unit. 2. The correction means according to claim 1, wherein said reading means reads said information in an optimal state from said recording medium in accordance with a difference between an average value of said tracking error signal and an initially set average value. 2. The disk drive device according to claim 1, wherein said tracking error signal is corrected. 3. An information reading method for reading information from a recording medium on which information is recorded with lands and grooves formed therein, wherein the tracking means generates a tracking error signal indicating a shift of a scanning position of the reading means on the recording medium. Correcting the tracking error signal; inverting the corrected tracking error signal to generate a tracking error inversion signal; and determining whether the reading unit is scanning the land or the groove. And a step of selecting either the tracking error signal or the inverted tracking error signal according to a result of the detection, and performing tracking control of the reading unit with the selected signal.