JP2004362672A - Tilt control method of optical disk reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tilt control method of an optical disk reproducing device performing reproduction operation of signal by an optical pickup. <P>SOLUTION: The optical pickup is moved to a prescribed position of an inner periphery side of a disk, while after focus control operation and equalizer adjustment of a RF signal amplifying circuit are performed, reproducing operation is performed, when the number of errors reaches the prescribed numbers in a reproducing operation state, reproducing operation is interrupted, while measuring operation of focus drive voltage and equalizer adjusting operation are performed, tilt adjustment is performed based on obtained DC voltage, while after tilt adjustment is performed based on an obtained equalizer adjustment value, reproducing operation is restarted from the interruption position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disc reproducing apparatus configured to perform a reproducing operation of a signal recorded on a disc by a laser emitted from an optical pickup.
[0002]
[Prior art]
2. Description of the Related Art Disk players that perform an operation of reading a signal recorded on a disk by using an optical pickup have become widespread, but recently, 4, 8, 12, and 16 times the specified recording linear velocity. An optical disk reproducing apparatus configured to reproduce a signal while controlling the rotation of the disk at a constant high linear velocity such as that described above has been developed.
[0003]
In an optical disk reproducing device, it is necessary to accurately irradiate a laser beam emitted from an optical pickup to a signal track on a disk surface, and a focus control operation and a tracking control operation are performed. Such a focus control operation is performed by supplying a drive current to a focusing coil that displaces the objective lens in the disk surface direction, and a tracking control operation is performed by supplying a drive current to a tracking coil that displaces the objective lens in the disk radial direction. It is done by doing.
[0004]
Recently, signal densification has been performed in order to record many signals on a disk, and in order to accurately perform the operation of reproducing a signal having a high density, the laser light must be optimally applied to the disk. It is necessary to irradiate the surface. In order to perform such an operation, an optical pickup configured to perform an operation of correcting a relative angle shift between a disk and an objective lens, that is, a tilt adjustment operation has been developed (for example, see Patent Reference 1).
Then, a technology has been developed in which the inclination of the pickup with respect to the disk is detected and the inclination is adjusted (for example, see Patent Document 2).
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-197698 [Patent Document 2]
JP-A-11-283264
[Problems to be solved by the invention]
In the technique described in Patent Document 2, data for performing a tilt control operation by moving an optical pickup from an inner peripheral position to an outer peripheral position of a disk, that is, data indicating a tilt of the disk is obtained. According to such a configuration, the tilt control operation according to the tilt of the disk can be performed, but the data measurement operation is performed before the reproduction operation of the signal recorded on the disk. Is time consuming.
[0007]
The above-described technique is effective because when the tilt characteristics of the disc are largely different between the inner circumference side and the outer circumference side of the disc, a tilt control operation suitable for the tilt of each disc can be performed. The inclination characteristics of the disk do not greatly differ between the inner circumference side and the outer circumference side, and in the case of a disk whose inclination characteristics do not greatly differ, the data measurement operation is useless.
[0008]
An object of the present invention is to provide a tilt control method suitable for an optical disc reproducing apparatus using an optical pickup capable of performing a tilt adjustment operation.
[0009]
[Action]
The present invention moves the optical pickup to a predetermined position on the inner peripheral side of the disk, performs focus control operation and adjusts the equalizer of the RF signal amplifier circuit, measures the focus drive voltage in the focused state, and obtains the focus drive voltage. The stored DC voltage is stored in the memory circuit, and the equalizer adjustment value when the optimum equalizer characteristics are obtained is stored in the memory circuit, and the tilt control signal set based on the stored DC voltage is stored in the tilt adjustment coil. The reproduction operation of the signal recorded on the disc is performed with the equalizer adjustment based on the supplied and stored equalizer adjustment value, and the reproduction operation is interrupted when the number of errors reaches a predetermined number in the reproduction operation state. And the focus drive voltage measurement operation and the equalizer adjustment operation were performed. And it is configured so as to resume the reproduction operation from the interrupt position after the tilt adjustment on the basis of the equalizer adjustment value obtained performs tilt adjustment on the basis of the flow voltage.
[0010]
【Example】
FIG. 1 is a flowchart showing a tilt control method of the present invention, and FIG. 2 is a block circuit showing one embodiment of an optical disk reproducing apparatus according to the present invention.
[0011]
In FIG. 2, reference numeral 1 denotes a disk which is rotationally driven by a spindle motor (not shown). Position information data is recorded in grooves or pits called pregrooves. The signal reproducing operation is performed based on the signal. Reference numeral 2 denotes an optical pickup for performing a reproducing operation of a signal recorded on the disk 1, which incorporates a laser diode for irradiating the disk 1 with a light beam and a monitoring diode for monitoring light emitted from the laser diode. And a photodetector 3 for receiving a light beam reflected from the signal surface of the disk 1.
[0012]
The optical pickup 2 includes a focusing coil 4 for displacing an objective lens (not shown) in the disk surface direction, a tracking coil 5 for displacing the objective lens in a radial direction of the disk 1, and an angle of the objective lens with respect to the disk 1. The tilt adjusting coil 6 for adjusting the tilt angle is incorporated.
[0013]
Reference numeral 7 denotes a focusing control operation for focusing a light beam of the optical pickup 2 on a signal surface of the disk 1 based on a signal obtained from a photodetector 3 incorporated in the optical pickup 2, and The pickup control circuit performs a tracking control operation for following a signal track on a signal surface, and is configured to output a tracking control signal based on a tracking error signal and a focusing control signal based on a focus error signal.
[0014]
Reference numeral 8 denotes a tracking coil drive circuit to which a tracking control signal output from the pickup control circuit 7 is input, and is configured to supply a drive signal to the tracking coil 5 incorporated in the optical pickup 2. . Reference numeral 9 denotes a focusing coil drive circuit to which a focusing control signal output from the pickup control circuit 7 is input. The focusing coil drive circuit 9 is configured to supply a drive signal to the focusing coil 4 incorporated in the optical pickup 2. .
[0015]
In such a configuration, the drive signal supplied from the focusing coil drive circuit 9 to the focusing coil 4 is a signal in which an AC signal is superimposed on a DC signal. The DC component in such a signal changes according to the distance between the objective lens and the disk 1. The value of the DC voltage is compared with a value set in the manufacturing process of the optical disk reproducing apparatus. Thus, the inclination of the disk can be determined.
[0016]
Reference numeral 10 denotes an RF signal amplifying circuit to which a signal obtained from the photodetector 3, that is, an RF signal (high-frequency signal) read out according to a signal recorded on the disk 1, is input, and outputs a binarized signal. It is configured to Further, the RF signal amplifying circuit 10 incorporates an equalizer circuit for adjusting the level of the input RF signal according to the frequency, so that the equalizer characteristics can be changed.
[0017]
For example, a pit signal having a different length from 3T to 11T is recorded on a CD disk, and the level of the RF signal, which is a signal obtained by reproducing these signals, is lower than that of the other signals. Become. Therefore, in such a case, the characteristics of the equalizer circuit are adjusted so as to increase the gain so as to amplify the level of the 3T signal larger than other signals.
[0018]
Reference numeral 11 denotes a digital signal processing circuit to which a binarized signal output from the RF signal amplifier circuit 10 is input, and is configured to perform a demodulation operation such as error correction of a reproduced signal. Reference numeral 12 denotes a signal reproducing circuit to which a signal demodulated by the digital signal processing circuit 11 is input. When the demodulated signal is an audio signal, the signal is converted into an analog signal and output to an amplifier or the like. In the case of such a data signal, the digital signal is output as it is.
[0019]
Reference numeral 13 denotes a system control circuit that performs demodulation operation and the like by the digital signal processing circuit 11 in accordance with the reproduction speed of the signal and performs various control operations, and 14 is detected in accordance with the error correction processing operation by the digital signal processing circuit 11. An error number detection circuit for detecting the number of error signals, and the detected value is configured to be input to the system control circuit 13. Reference numeral 15 denotes a position detection circuit for detecting a position on the disk based on the position information data recorded on the disk 1. When a reproducing operation is performed, information indicating the reproducing position is input and the position is detected. Is stored.
[0020]
Numeral 16 denotes an equalizer changing circuit for changing the equalizer characteristics of the RF signal amplifying circuit 10, and the operation thereof is controlled by the system control circuit 13.
[0021]
In such a configuration, the system control circuit 13 is in a state where the focus drive signal supplied to the focusing coil 4 from the focusing coil drive circuit 9 is input, and detects a DC voltage value included in the drive signal. It is configured. Reference numeral 17 denotes a drive voltage value memory circuit in which the DC voltage value detected by the system control circuit 13 is stored together with the position information detected by the position detection circuit 15, and a write operation and a read operation are performed by the system control circuit 13. It is configured to be controlled. The equalizer adjusting operation of the RF signal amplifying circuit 10 by the equalizer changing circuit 16 detects the level of the 3T signal included in the signal amplified by the RF signal amplifying circuit 10 and sets the level to a predetermined level. Done. Reference numeral 18 denotes an equalizer adjustment value memory circuit in which an equalizer adjustment value equalized by the system control circuit 13 is stored together with the position information detected by the position detection circuit 15, and a write operation and a read operation are performed by the system control circuit 13. It is configured to be controlled by
[0022]
Further, a DC voltage value and an equalizer adjustment value measured at a predetermined position at the time of manufacturing and shipment of the optical disk reproducing apparatus, for example, at a position called a lead-in where data indicating a position of a signal recorded on the disk are recorded, are recorded in the system. It is stored in a nonvolatile memory incorporated in the control circuit 13.
[0023]
Reference numeral 19 denotes a tilt control circuit that outputs a tilt control signal based on a signal output from the system control circuit 13 in accordance with a DC voltage value stored in the drive voltage value memory circuit 17, and is stored in advance. It is configured to output a DC voltage for tilt adjustment set according to the DC voltage value.
[0024]
Reference numeral 20 denotes an amplifier circuit for amplifying the tilt control signal output from the tilt control circuit 19, reference numeral 21 denotes a capacitor for cutting a DC signal from the focus drive signal output from the focusing coil drive circuit 9, and reference numeral 22 denotes the capacitor 21. Is an amplifying circuit to which an AC signal passing through is input and amplifies the signal. 23 is an addition circuit for adding the tilt control signal amplified by the amplification circuit 20 and the AC signal amplified by the amplification circuit 22, and 24 is supplied with the tilt adjustment signal added by the addition circuit 23. The tilt coil driving circuit is connected to supply a driving signal to a tilt adjusting coil 6 incorporated in the optical pickup 2.
[0025]
The optical disc reproducing apparatus according to the present invention is configured as described above. Next, the tilt control method according to the present invention will be described with reference to the flowchart shown in FIG.
[0026]
When the disc 1 is placed on a turntable incorporated in an optical disc reproducing apparatus for performing a reproducing operation, the optical pickup 2 is moved to a predetermined position on the inner peripheral side of the disc, for example, the position of a signal recorded on the disc. The focus control operation of moving the laser light to the signal surface by moving the data to the lead-in area where the indicated data is recorded, and the operation of adjusting the equalizer characteristics to accurately perform the binarization operation by the RF signal amplifier circuit 10 are performed. (Step A). Such a focus control operation is performed by a focus servo operation of the pickup control circuit 7 based on a signal obtained from the photodetector 3, and an equalizer adjustment operation is performed by a control operation of the system control circuit 13 for the equalizer change circuit 16.
[0027]
When the operation in step A is performed, it is determined whether the focus control operation and the equalizer adjustment operation have been performed normally (step B). If the focus control operation or the equalizer adjustment operation is not performed normally in step B, it is determined that the disk 1 is defective or the disk 1 is mounted upside down, and disk error processing is performed (step C). If it is determined in step B that the focus control has been performed normally and the equalizer adjustment has been performed normally, the disk 1 is driven to rotate by the spindle motor, and the DC voltage is reduced from the focus drive voltage supplied to the focusing coil 4. The operation of measuring the voltage, storing the voltage value in the drive voltage value memory circuit 17, and storing the equalizer adjustment value when the equalizer adjustment is performed in the equalizer adjustment value memory circuit 18 is performed (step D).
[0028]
In step D, when the DC voltage included in the focus drive voltage is measured, a signal corresponding to the measured value is output from the system control circuit 13 to the tilt control circuit 17 and the equalizer adjustment operation by the equalizer change circuit 16 Is performed. As a result, a tilt control signal set in advance corresponding to the signal is output from the tilt control circuit 19 and an equalizer adjustment operation for the RF signal amplifier circuit 10 is performed.
[0029]
The DC signal output from the tilt control circuit 19 is input to the amplification circuit 20, amplified, and then input to the addition circuit 23. On the other hand, the drive signal output from the focusing coil drive circuit 9 is input to an amplifier circuit 22 via a capacitor 21. The signal input to the amplifier circuit 22 is an AC signal from which a DC signal has been cut, that is, a disk. This is a signal for displacing the objective lens with respect to the surface shake of No. 1. The AC signal amplified by the amplifier circuit 22 is input to the adder circuit 23 and added to the DC signal amplified by the amplifier circuit 20, and then input to the tilt coil drive circuit 24.
[0030]
As a result, a tilt adjustment signal in which an AC signal is superimposed on a DC signal set at an inner circumferential position on the disk 1 is supplied from the tilt coil drive circuit 24 to the tilt adjustment coil 6 incorporated in the optical pickup 2. Is done. Therefore, the tilt adjustment of the objective lens by the tilt adjusting coil 6 is performed. The value of the DC signal output from the tilt control circuit 19 for adjusting the tilt of the objective lens is determined by comparing the DC voltage value measured at the time of manufacture and shipment of the optical disk reproducing device and stored in the nonvolatile memory with the disk 1. The setting operation is set based on the relationship between the DC voltage values measured and used, and the setting operation is set based on an experimental value. Similarly, the equalizer adjustment value is adjusted at the time of manufacture and shipment of the optical disc reproducing apparatus and is set based on the adjustment value stored in the nonvolatile memory. Such setting operation is set based on an experimental value. .
[0031]
When the operation in step D is performed, the above-described tilt control operation and equalizer adjustment operation are performed, and the reproduction operation is performed (step E). That is, the reproduction operation is continued with the level of the tilt control signal output from the tilt control circuit 19 being fixed and the adjustment value by the equalizer changing circuit 16 being fixed. The signal recorded on the disk 1 is reproduced by the optical pickup 2 in which the focusing control operation and the tracking control operation by the pickup control circuit 7 and the tilt control operation by the tilt control circuit 19 are performed.
[0032]
The signal reproduced by the optical pickup 2 is input to an RF signal amplifier circuit 10 where it is amplified, binarized, and output to a digital signal processing circuit 11. The reproduction signal input to the digital signal processing circuit 11 is subjected to demodulation processing such as error correction and output to the signal reproduction circuit 12. As a result, a reproduction processing operation is performed by the signal reproduction circuit 12, and a reproduction signal is output to a personal computer or the like.
[0033]
As described above, the operation of reproducing the signal recorded on the disk 1 is performed. In the state where such operation is performed, the operation of detecting the reproduction position by the position detection circuit 15 and the number of errors by the error number detection circuit 14 are performed. Is detected. The operation of detecting the number of errors by the error detection circuit 14 can be performed by counting signals obtained by the error correction processing operation by the digital signal processing circuit 11. In this state, the number of errors detected by the error number detection circuit 14 is input to the system control circuit 13, and the system control circuit 13 determines whether the number of errors has reached a predetermined number (step F). . This set number is set to a value immediately before the error correction processing operation by the digital signal processing circuit 11 cannot be performed accurately.
[0034]
In step F, if the number of errors does not reach the predetermined number, the reproducing operation is continued as it is, the reproducing operation is performed to the final position of the signal recorded on the disk 1 and the optical disk reproducing device is returned to the stopped state. Can be If it is determined in step F that the number of errors has reached the predetermined number, the reproduction operation is interrupted, the DC voltage of the focus drive voltage at that position is measured, and the value is stored in the drive voltage value memory circuit 17. An operation of adjusting the equalizer circuit and storing the adjustment value in the equalizer adjustment value memory circuit 18 is performed (step G). When the interruption operation is performed, the position information indicating the reproduction interruption position is detected by the position detection circuit 15 and the position information is stored.
[0035]
When the DC voltage of the focus drive voltage at the reproduction interruption position is measured and the value is stored in the drive voltage value memory circuit 17, a signal based on the DC voltage stored in the memory circuit 17 is output to the tilt control circuit 19. The tilt control signal corresponding to the signal is output from the tilt control circuit 19. When such a tilt control signal is output from the tilt control circuit 19, a drive signal for tilt adjustment is supplied from the tilt coil drive circuit 24 to the tilt adjustment coil 6 incorporated in the optical pickup 2. When the drive signal from the tilt coil drive circuit 24 is supplied to the tilt adjustment coil 6 in this manner, the operation of adjusting the tilt of the objective lens to an optimum state with respect to the signal surface of the disk 1, that is, the tilt adjustment operation is performed. Done.
[0036]
Further, when an equalizer adjustment operation is performed by the equalizer changing circuit 16 on the RF signal amplifier circuit 10 at the reproduction interruption position, the adjustment value is stored in the equalizer adjustment value memory circuit 18. When the adjustment value is stored in the equalizer adjustment value memory circuit 18, an equalizer adjustment operation based on the adjustment value stored in the memory circuit 18 is performed on the RF signal amplifier circuit 10.
[0037]
When the above-described adjustment operations are performed, the optical pickup 2 is moved to the position where the reproduction was interrupted, and the reproduction operation is restarted (Step H). If the reproduction operation is restarted after performing the tilt adjustment operation and the equalizer adjustment operation, the operation of reading the signal from the disk 1 can be performed accurately. Is reduced. In this way, when the reproducing operation is started, the process returns to step F, and the above-described operation is repeatedly performed.
[0038]
As described above, according to the present invention, when the number of errors increases during playback, the playback operation is interrupted, and the playback operation is resumed after performing the tilt adjustment operation and the equalizer adjustment operation. The reproduction operation of the signal recorded in No. 1 can be performed without any trouble.
[0039]
In the present embodiment, the tilt adjustment operation is performed when the number of errors reaches a predetermined number during the reproducing operation. However, the focus drive obtained by measuring when the first error number reaches the predetermined number is obtained. Obtained from the difference between the voltage value and the focus drive voltage value measured at the inner peripheral position and the distance between the predetermined position on the inner peripheral side and the position where the number of errors reaches a predetermined number and the reproduction operation is interrupted. If the tilt of the disc 1 is approximated from the relational expression given below and the value of the tilt signal output from the tilt control circuit 19 is changed and corrected by the approximated value, the tilt adjustment is performed from the first reproduction interruption position to the outer peripheral side. Since the operation is performed in accordance with the reproduction position, it is possible to avoid a state where the number of errors reaches a predetermined value due to the tilt adjustment failure, and it is possible to continue the normal reproduction operation.
[0040]
In this embodiment, the error detection circuit 14 is provided to interrupt the reproduction operation when the number of detected errors reaches a predetermined number. That is, the disk 1 of the optical pickup 2 is increased by increasing the number of errors. Was determined to have shifted, but a jitter amount detection circuit for detecting the amount of jitter included in the reproduced signal was provided, and it was determined whether the amount of jitter reached a predetermined amount. May be performed. As a technique for detecting such a jitter amount, a known technique may be used, and a description thereof will be omitted.
[0041]
Further, in the present embodiment, the predetermined position on the inner peripheral side is the position where the data indicating the position of the signal recorded on the disc is recorded, but the position can be set freely.
[0042]
【The invention's effect】
The present invention moves the optical pickup to a predetermined position on the inner peripheral side of the disk, performs focus control operation and adjusts the equalizer of the RF signal amplifier circuit, measures the focus drive voltage in the focused state, and obtains the focus drive voltage. The stored DC voltage is stored in the memory circuit, and the equalizer adjustment value when the optimum equalizer characteristics are obtained is stored in the memory circuit, and the tilt control signal set based on the stored DC voltage is stored in the tilt adjustment coil. The reproducing operation of the signal recorded on the disc is performed in a state where the equalizer adjustment based on the supplied and stored equalizer adjustment value is performed, and in the reproducing operation state, when the number of errors reaches a predetermined number, or when the amount of jitter is reduced. When the predetermined amount is reached, the reproducing operation is interrupted, and the focus driving voltage measuring operation and After performing the equalizer adjustment operation, performing the tilt adjustment based on the obtained DC voltage, performing the tilt adjustment based on the obtained equalizer adjustment value, and then restarting the playback operation from the interrupted position, mount the disc The subsequent reproduction operation can be started immediately.
[0043]
Further, the present invention provides a tilt control signal between a reproduction interruption position and an outermost peripheral position of a disc based on a DC voltage obtained at a predetermined position on an inner peripheral side and a DC voltage obtained at a reproduction interruption position. Is generated, so that the operation of reproducing the signal recorded on the disc can be promptly performed.
[0044]
According to the present invention, the predetermined position on the inner peripheral side is set to the position where the data indicating the position of the signal recorded on the disk is recorded, so that the reproduction operation of the signal recorded on the disk is performed. Since the operation of measuring the focus drive voltage can be performed while the operation of reproducing the signal which is always read out is performed, the measurement adjustment operation can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating a tilt control method according to the present invention.
FIG. 2 is a block circuit diagram showing one embodiment of an optical disc reproducing apparatus according to the present invention.
[Explanation of symbols]
Reference Signs List 1 disc 2 optical pickup 4 focusing coil 6 tilt adjustment coil 7 pickup control circuit 9 focusing coil drive circuit 10 RF signal amplification circuit 11 digital signal processing circuit 13 system control circuit 14 error number detection circuit 15 position detection circuit 16 equalizer change circuit 17 Drive voltage value memory circuit 18 Equalizer adjustment value memory circuit 19 Tilt control circuit 24 Tilt coil drive circuit

Claims (4)

The optical pickup is moved to a predetermined position on the inner peripheral side of the disc, and the focus control operation and the equalizer adjustment of the RF signal amplifier circuit are performed, the focus drive voltage in the focused state is measured, and the obtained DC voltage is measured. The equalizer adjustment value when the optimum equalizer characteristics are obtained is stored in the memory circuit and the equalizer adjustment value is stored in the memory circuit, and the tilt control signal set based on the stored DC voltage is supplied to the tilt adjustment coil and stored. The reproduction operation of the signal recorded on the disc is performed in a state where the equalizer adjustment based on the adjusted equalizer adjustment value has been performed. Perform the voltage measurement operation and equalizer adjustment operation. Tilt control method of the optical disc reproducing apparatus being characterized in that from the interrupted position after the tilt adjustment so as to resume the reproduction operation on the basis of the equalizer adjustment value obtained performs tilt adjustment Zui. The optical pickup is moved to a predetermined position on the inner peripheral side of the disc, and the focus control operation and the equalizer adjustment of the RF signal amplifier circuit are performed, the focus drive voltage in the focused state is measured, and the obtained DC voltage is measured. The equalizer adjustment value when the optimum equalizer characteristics are obtained is stored in the memory circuit and the equalizer adjustment value is stored in the memory circuit, and the tilt control signal set based on the stored DC voltage is supplied to the tilt adjustment coil and stored. The playback operation of the signal recorded on the disc is performed in a state where the equalizer adjustment based on the equalized adjustment value is performed. Perform the voltage measurement operation and equalizer adjustment operation. Tilt control method of the optical disc reproducing apparatus being characterized in that from the interrupted position after the tilt adjustment so as to resume the reproduction operation on the basis of the equalizer adjustment value obtained performs tilt adjustment Zui. A tilt control signal between the reproduction interruption position and the outermost position of the disc is generated based on the DC voltage obtained at a predetermined position on the inner circumference side and the DC voltage obtained at the reproduction interruption position. The tilt control method according to claim 1 or 2, wherein: 3. The tilt control method according to claim 1, wherein a predetermined position on the inner peripheral side is set to a position where data indicating a position of a signal recorded on the disk is recorded.

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