JP2000276855A - Disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely reproduce data even though an optical disk to be reproduced is a relatively inferior one having wound or distortion, etc., by changing over a capture range of a clock reproducing circuit according to a signal reading position on a disk by an optical pickup. SOLUTION: When a microcomputer 17 confirms that a signal reading position of a pickup on a disk has reached a signal reading position stored in a storage part 16 based on the address information corresponding to the signal reading position of the pickup on the disk obtained from a signal processing circuit 13, the microcomputer transmits a setting change signal to a range change-over circuit 25. Based on the setting change signal, the range change-over circuit 25 changes over a pre-set capture range of a PLL circuit 18 to a capture range of another frequency band. The signal processor circuit 13 executes (searches) error correction again by using a PLL clock, and caries out EFM demodulation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a disk device for reading information recorded on an optical disk such as a CD-ROM or a DVD-ROM.

[0002]

2. Description of the Related Art In recent years, with the spread of various types of optical disk drives, optical disks that can be reproduced or recorded have become available at relatively low prices. On the other hand, due to media cost competition, optical disks of poor quality have come to market. In addition, a high-speed recording / playback competition of a disk drive is also helped, and a bad optical disk having a poor recording state may be manufactured by a disk writing device such as a CD-R. Therefore, under such circumstances, a wider range of reading ability is required for the disk drive.

[0003]

However, the conventional disk drive has the following problems. That is,
As shown in the timing chart of FIG. 13 and the flowchart of FIG. 14, the microcomputer of the conventional disk device executes error correction by a signal processing circuit using a PLL clock of a PLL circuit preset to a predetermined capture range (searching). If the error correction fails, the number of error correction failures is counted (S51) (S5).
2). Further, when the microcomputer confirms that the number of error correction failures preset in the storage unit has been exceeded (S
53), and displays an error message on the display unit (S5).
4) Forcibly terminate the data reproduction process (demodulation). For this reason, the conventional disk device often cannot reproduce a bad optical disk having, for example, a defect or distortion in a track.

Accordingly, the present invention has been made to solve such a problem, and data can be reliably reproduced even if an optical disc to be reproduced is a relatively bad optical disc having, for example, a defect or distortion. It is intended to provide a disk device.

[0005]

According to a first aspect of the present invention, there is provided a disk drive for reading a signal from a disk, and a disk drive for reading a signal from the disk. A clock recovery circuit for recovering a clock for data recovery from the read signal, and means for switching a capture range of the clock recovery circuit in accordance with a signal read position on the disk by the optical pickup. And

According to the disk device of the present invention, a signal read position by an optical pickup on a disk is
The capture range of the clock recovery circuit can be switched, so that the optical pickup can respond to changes in circumstances, such as when playing back the inner or outer circumference of the disc, or when playing back a defective or distorted part of the disc. Thus, it is possible to optimally set the frequency band of the clock reproduced by the clock reproduction circuit. As a result, the synchronization signal can be more reliably detected, and data can be reproduced (demodulated) correctly.

[0007] The disk device of the present invention is characterized in that
An optical pickup for reading a signal from a disk, a clock recovery circuit for recovering a clock for data recovery from the signal read by the optical pickup, and a clock recovered by the clock recovery circuit A signal processing circuit that reproduces data by using the method, and performs error correction on the reproduced data; and a unit that switches a capture range of the clock reproduction circuit in accordance with the state of error correction by the signal processing circuit. It is characterized by the following.

According to the disk device of the present invention, the capture range of the clock recovery circuit can be switched when, for example, error correction of data reproduced using the clock obtained from the clock recovery circuit has failed a predetermined number of times. Therefore, the error correction of the data reproduced using the clocks of the different frequency bands whose ranges have been switched can be performed again, and the appropriate data reproduction can be performed.

Further, according to a third aspect of the present invention, there is provided an optical pickup for reading a signal from a disk, and a clock for reproducing data from the signal read by the optical pickup. A clock recovery circuit, a signal processing circuit that recovers data using the clock recovered by the clock recovery circuit, and performs error correction on the recovered data. Storage means for storing a reproduction failure position of the disk, and means for switching a capture range of the clock reproduction circuit based on the contents stored in the storage means.

According to the disk device of the present invention, in addition to the function and effect of the disk device according to the second aspect, it is possible to store the position of a defective reproduction of the disk by the optical pickup when error correction has failed, for example, a predetermined number of times. So
By playing back various discs, it is possible to learn the position on the disc at which the capture range should be switched, and it is possible to substantially reduce the tendency of the disc apparatus on the disc to be difficult to reproduce.

[0011] The disk device of the present invention is characterized in that:
An optical pickup for reading a signal from a disk, a clock recovery circuit for recovering a clock for data recovery from the signal read by the optical pickup, and a clock recovered by the clock recovery circuit A signal processing circuit that reproduces data by using, and an error correction of the reproduced data; and a storage unit that stores a reproduction failure position for each disk according to an error correction state by the signal processing circuit; Means for switching the capture range of the clock recovery circuit based on the contents stored for each disk in the storage means.

According to the disk device of the present invention, in addition to the operation and effect of the disk device according to the third aspect, the position of a defective reproduction of the disk by the optical pickup when error correction has failed, for example, a predetermined number of times is stored for each disk. This makes it possible to learn the position on the disk where the capture range should be switched each time the reproduction of a certain disk is repeated, thereby substantially reducing the difficult-to-reproduce portions on a specific disk and reproducing (demodulating) data. Can be shortened.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing the structure of a disk device according to a first embodiment of the present invention, FIG. 2 is a block diagram showing the structure of an optical pickup incorporated in the disk device, and FIG. FIG. 4 is a block diagram schematically showing a circuit configuration of the device, and FIG. 4 is a diagram showing a signal processing unit in FIG. 3 in detail.

As shown in FIG. 1, the disk drive according to the present embodiment comprises a disk motor 2 for driving a disk 1 to rotate.
And a pickup 3 for reading signals recorded on the disk 1, a feed motor 4 for moving the pickup 3 in the radial direction of the disk 1, and a main board on which a microcomputer, a signal processing circuit and the like are mounted. ing.

In the pickup 3, as shown in FIG.
A light emitting diode 5 that emits laser light, an objective lens 6 that converges the laser light emitted from the light emitting diode 5 and irradiates the surface of the disk 1, and an object lens 5 for moving and controlling the objective lens 5 in a focus direction or a tracking direction. Focusing coil 7 or tracking coil 8
And a light receiving element 9 for receiving the reflected light from the disk 1.

The circuit configuration of the disk drive will be described. As shown in FIG. 3, a signal read by the pickup 3 from the disk 1 driven by the disk motor 2 is supplied to the RF amplifier 10. RF amplifier 10
Extracts a focus error signal or a tracking error signal from an output of the pickup 3 and supplies the signal to a focus / tracking circuit, and also outputs the amplified RF signal to a level slice / PLL circuit 12 in the signal processing unit 11.
Supply to The level slice / PLL circuit 12 binarizes the amplified and supplied RF signal to obtain an EFM signal, and generates a PLL clock synchronized with the EFM signal in order to read the EFM signal.

The EFM signal and the PLL clock are supplied to a signal processing circuit 13. The signal processing circuit 13
The synchronization signal is detected using the LL clock, and error correction and EFM demodulation are performed based on the synchronization signal. The signal processing circuit 13 supplies the demodulated reproduced data to an I / F (interface) 14. The I / F 14 controls communication with an interface such as transmission and reception of various operation commands and data with the host computer 15. The operation command is transmitted and received between the host computer 15 and the microcomputer 17 having at least the storage unit 16 via the I / F 14.

Here, the level slice / PLL circuit 12
Will be described in detail. As shown in FIG. 4, the PLL circuit 18 controls the local frequency so that the difference (intermediate frequency) between the oscillation frequency of the local oscillator and the input signal frequency (intermediate frequency) becomes constant.
C) 19, a low-pass filter (LPF) 20, an amplifier (AMP) 21, a voltage-controlled oscillator (VCO) 22,
Comparing the phases of the output f ₀ of the input signal f _s and the voltage controlled oscillator 22, and two signals of a phase comparator for generating a difference signal voltage corresponding to the phase difference (PC) 23, which is oscillated from the clock generator 24 The frequency is switched based on the setting change information from the microcomputer 17, and the clock signal whose frequency has been switched is used as a reference clock by the VCO 22.
And a range switching circuit 25 for supplying to the power supply.

The difference voltage signal V passed through the low-pass filter 20
_d is amplified through an amplifier 21 and a voltage controlled oscillator 22
Is controlled in a DC manner. Voltage controlled oscillator 22
Is such that the difference between the oscillation frequencies f ₀ and f _s is small.
₀ is controlled in a DC manner, and when the difference disappears, f
₀ will be locked to the f _s, it is possible to reliable data reading. Thus, the PLL circuit 18
The capture range can be switched to generate a PLL clock synchronized with the frequency of the EFM signal. Therefore, the voltage controlled oscillator 22 generates a frequency clock corresponding to the capture range, and the signal processing circuit 13 reproduces data based on the clock.

Next, control of the PLL circuit 18 performed by the microcomputer 17 of the disk device of the present embodiment will be described with reference to a timing chart shown in FIG. 5 and a flowchart shown in FIG.

Based on the address information corresponding to the signal reading position of the pickup 3 on the disk 1 obtained from the signal processing circuit 13, the microcomputer 17 stores the signal reading position of the pickup 3 on the disk 1 in the storage unit 16 in advance. When it is confirmed that the signal has reached the stored signal reading position (S1), a setting change signal is transmitted to the range switching circuit 25 (S2). As a result, the capture range of the PLL circuit 18 is switched from a preset range to a capture range of another frequency band. The signal processing circuit 13 executes (searches) error correction again using the PLL clock, and performs EFM demodulation (S3).

As described above, according to the disk device of the present embodiment, the capture range of the PLL circuit 18 can be switched according to the signal reading position of the pickup 3 on the disk 1, so that the pickup 3 The frequency band of the clock reproduced by the PLL circuit 18 is set optimally in response to a change in the situation, such as when reproducing the inner or outer periphery of the disk, or when reproducing a portion having a defect or distortion of the disk. It becomes possible. As a result, the synchronization signal can be more reliably detected, and data can be reproduced (demodulated) correctly.

Next, a second embodiment of the present invention will be described. In the disk device of the second embodiment, the control of the PLL circuit 18 performed by the microcomputer is partially different from the disk device of the first embodiment as shown in the timing chart of FIG. 7 and the flowchart of FIG.

That is, the microcomputer of the disk device of this embodiment executes error correction (search A) by the signal processing circuit 13 using the PLL clock of the current capture range of the PLL circuit 18 and fails to correct the error. Then, the number of error correction failures is counted (S11) and counted (S12). When the microcomputer confirms that the number of error correction failures preset in the storage unit 16 has been exceeded (S13), A setting change signal is transmitted to the range switching circuit 25 (S14). As a result, the capture range of the PLL circuit 18 is switched from a preset range to a capture range of another frequency band. The signal processing circuit 13 executes error correction again using the PLL clock switched to another frequency band (search B),
FM demodulation is performed (S15).

As described above, according to the disk device of the present embodiment, when error correction of data reproduced using the clock obtained from the PLL circuit 18 has failed for a predetermined number of times, for example, the capture of the PLL circuit 18 is performed. Since the range can be switched, it is possible to perform error correction again on the data reproduced using the clocks of the different frequency bands whose range has been switched, and it is possible to perform appropriate data reproduction.

A third embodiment of the present invention will be described. In the disk device of the third embodiment, the control of the PLL circuit 18 performed by the microcomputer is partially different from the disk device of the second embodiment as shown in the timing chart of FIG. 9 and the flowchart of FIG.

That is, the microcomputer of the disk device of the present embodiment executes error correction (search A) by the signal processing circuit 13 using the PLL clock in the current capture range of the PLL circuit 18 and fails to correct the error. Then, the number of error correction failures is counted (S21) and counted (S22). When the microcomputer confirms that the number of error correction failures preset in the storage unit 16 has been exceeded (S23), A setting change signal is transmitted to the range switching circuit 25 (S24). As a result, the capture range of the PLL circuit 18 is switched from a preset range to a capture range of another frequency band. The signal processing circuit 13 executes error correction again using the PLL clock switched to another frequency band (search B),
FM demodulation is performed (S25). Further, in this case, the signal reading position (address information of the disk 1) on the disk 1 by the pickup 3 when the error correction exceeds a predetermined number of failures is stored (learned) in the storage unit 16 (S2).
6).

(After learning) Based on the address information corresponding to the signal reading position on the disk 1 of the pickup 3 obtained from the signal processing circuit 13, the microcomputer 17 (S27)
The current signal read position on the disk 1 by the pickup 3 is the signal read position stored (learned) in the storage unit 16, that is, the signal read position on the disk 1 by the pickup 3 when error correction has exceeded a predetermined number of failures before. (S28), a setting change signal is transmitted to the range switching circuit 25 (S2).
9). As a result, the capture range of the PLL circuit 18 is switched from a preset range to a capture range of another frequency band. The signal processing circuit 13
Error correction is again performed using the LL clock (search:
S3), EFM demodulation is performed (S30).

As described above, according to the disk device of the present embodiment, in addition to the operation and effect of the disk device of the second embodiment, the position of defective reproduction of the disk by the pickup 3 when error correction fails, for example, a predetermined number of times. Since it is possible to store, by playing back various discs, it is possible to learn the position on the disc where the capture range should be switched, and to substantially reduce the tendency of the disc drive to play on the disc which is difficult to play. be able to.

Next, a fourth embodiment of the present invention will be described. In the disk device of the fourth embodiment, the control of the PLL circuit 18 performed by the microcomputer is partially different from the disk device of the third embodiment as shown in the timing chart of FIG. 11 and the flowchart of FIG.

That is, the microcomputer of the disk device of this embodiment executes error correction (search A) by the signal processing circuit 13 using the PLL clock of the current capture range of the PLL circuit 18 and fails to correct the error. Then, the number of error correction failures is counted (S31) and counted (S32). When the microcomputer confirms that the number of error correction failures set in advance in the storage unit 16 has been exceeded (S33), A setting change signal is transmitted to the range switching circuit 25 (S34). As a result, the capture range of the PLL circuit 18 is switched from a preset range to a capture range of another frequency band. The signal processing circuit 13 executes error correction again using the PLL clock switched to another frequency band (search B),
FM demodulation is performed (S35). Further, in this case, the signal reading position (address information of the disk 1) on the disk 1 by the pickup 3 when the error correction exceeds a predetermined number of failures is stored in the storage unit 16 together with a serial number or the like unique to the disk. (S36).

(At the time of the second or subsequent reproduction of a certain disc) The microcomputer 17 determines the current pickup based on the address information corresponding to the signal reading position of the pickup 3 on the disc 1 obtained by the signal processing circuit 13 (S37). The signal reading position on the disk 1 by the pickup 3 is the signal reading position stored in the storage unit 16 together with the serial number of the disk, that is, the signal reading position on the disk 1 by the pickup 3 when the error correction has previously exceeded a predetermined number of failures. (S38), a setting change signal is transmitted to the range switching circuit 25 (S3).
9). As a result, the capture range of the PLL circuit 18 is switched from a preset range to a capture range of another frequency band. The signal processing circuit 13
Error correction is again performed using the LL clock (search:
S3), EFM demodulation is performed (S40). in this way,
According to the disk device of the present embodiment, in addition to the operation and effect of the disk device of the third embodiment, it is possible to store the defective reproduction position of the disk by the pickup 3 when error correction has failed, for example, a predetermined number of times for each disk. So you can
Each time the reproduction of a certain disc is repeated, the position on the disc at which the capture range should be switched can be learned, so that it is possible to substantially reduce difficult-to-reproduce portions on a predetermined disc and to shorten the time required for data reproduction (demodulation). be able to.

In the above embodiment, the present invention has been described merely as a disk device. However, a CD-ROM drive, a CD-R drive, a DVD-ROM, or a DV
The present invention can be applied to various types of disk drives such as a D-RAM drive and the like.

[0035]

As described above, according to the disk device of the first aspect, the capture range of the clock recovery circuit can be switched according to the signal reading position of the optical pickup on the disk. The frequency band of the clock reproduced by the clock reproducing circuit is adjusted in response to a change in the situation, for example, when the pickup reproduces the inner or outer periphery of the disk, or reproduces a defective or distorted part of the disk. It is possible to set optimally. As a result, the synchronization signal can be more reliably detected, and data can be reproduced (demodulated) correctly.

According to the second aspect of the present invention, when the error correction of the data reproduced using the clock obtained from the clock reproduction circuit has failed, for example, a predetermined number of times, the capture range of the clock reproduction circuit is switched. Therefore, the error correction of the data reproduced using the clock of the different frequency band whose range has been switched can be performed again, and the appropriate data reproduction can be performed.

According to the disk device of the third aspect, in addition to the operation and effect of the disk device of the second aspect, the position of a defective reproduction of the disk by the optical pickup when error correction has failed, for example, a predetermined number of times is stored. Therefore, by playing various discs, it is possible to learn the position on the disc where the capture range should be switched, and it is possible to substantially reduce the difficult-to-play spots on the disc in the tendency of the disc device. it can.

According to the disk device of the fourth aspect, in addition to the operation and effect of the disk device of the third aspect, when the error correction has failed, for example, a predetermined number of times, the position of a defective reproduction of the disk by the optical pickup is determined. Therefore, each time the reproduction of a certain disc is repeated, the position on the disc at which the capture range should be switched can be learned. Demodulation) can be shortened.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a disk device according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically showing a pickup of the disk device of FIG. 1;

FIG. 3 is a diagram schematically showing a circuit configuration of the disk device of FIG. 1;

FIG. 4 is a view showing a PLL circuit of the disk device of FIG. 1;

FIG. 5 is a timing chart showing control of a PLL circuit by a microcomputer of the disk device of FIG. 1;

FIG. 6 is a flowchart showing control of a PLL circuit by a microcomputer of the disk device of FIG. 1;

FIG. 7 is a timing chart showing control of a PLL circuit by a microcomputer of the disk device according to the second embodiment of the present invention.

FIG. 8 is a flowchart showing control of a PLL circuit by a microcomputer of the disk device according to the second embodiment of the present invention.

FIG. 9 is a timing chart showing control of the PLL circuit by the microcomputer of the disk device according to the third embodiment of the present invention.

FIG. 10 is a flowchart showing control of the PLL circuit by the microcomputer of the disk device according to the third embodiment of the present invention.

FIG. 11 is a timing chart showing the control of the PLL circuit by the microcomputer of the disk device according to the fourth embodiment of the present invention.

FIG. 12 is a flowchart showing control of the PLL circuit by the microcomputer of the disk device according to the fourth embodiment of the present invention.

FIG. 13 shows a PLL by a microcomputer of a conventional disk drive.
6 is a timing chart illustrating control of a circuit.

FIG. 14 shows a PLL by a microcomputer of a conventional disk drive.
5 is a flowchart illustrating control of a circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Disc 3 ... Pickup 4 ... Feed motor 12 ... Level slice / PLL circuit 13 ... Signal processing circuit 16 ... Storage unit 17 ... Microcomputer 18 ... PLL circuit 24 ... Clock generator 25 ... Range Switching circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazumi Sugiyama 3-3-9, Shimbashi, Minato-ku, Tokyo F-term (reference) in Toshiba AV EE Co., Ltd. 5D044 BC03 BC06 CC04 DE68 GM11 GM12 5D090 AA01 BB02 BB04 CC04 FF07 GG26

Claims (4)

[Claims] An optical pickup for reading a signal from a disk; a clock recovery circuit for recovering a clock for data recovery from the signal read by the optical pickup; and a clock recovery circuit for reading a signal on the disk by the optical pickup. Means for switching the capture range of the clock recovery circuit accordingly. 2. An optical pickup for reading a signal from a disk, a clock reproducing circuit for reproducing a clock for data reproduction from a signal read by the optical pickup, and a clock reproduced by the clock reproducing circuit. A signal processing circuit that reproduces data and performs error correction on the reproduced data; and a unit that switches a capture range of the clock recovery circuit in accordance with a state of error correction by the signal processing circuit. Disk device. 3. An optical pickup for reading a signal from a disk, a clock reproducing circuit for reproducing a clock for data reproduction from a signal read by the optical pickup, and a clock reproduced by the clock reproducing circuit. A signal processing circuit that reproduces data, and performs error correction of the reproduced data; a storage unit that stores a reproduction failure position of the disk according to an error correction state of the signal processing circuit; Means for switching the capture range of the clock recovery circuit based on the stored contents. 4. An optical pickup for reading a signal from a disk, a clock reproducing circuit for reproducing a clock for reproducing data from a signal read by the optical pickup, and a clock reproduced by the clock reproducing circuit. A signal processing circuit that reproduces data and performs error correction of the reproduced data; a storage unit that stores a reproduction failure position for each disk according to an error correction state of the signal processing circuit; Means for switching a capture range of the clock recovery circuit based on contents stored for each of the disks.