JP2005149672A - Optical disk recording/reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk recording/reproducing device capable of surely performing a disk discriminating operation. <P>SOLUTION: This device is provided with a band pas filter circuit 18 capable of changing filter characteristics so as to extract the wobbling signal of a different frequency obtained from a pregroove. The filter characteristics of the band pass filter circuit 18 are set to characteristics to extract the wobbling signal of a first recording disk. When the frequency of the wobbling signal extracted by the band pass filter circuit 18 is the frequency of the first recording disk, the disk is subjected to rotary drive control as the first recording disk so that linear velocity is made constant by using a synchronous signal obtained from the wobbling signal, and whether the rotary drive operation becomes a locked state or not is determined to determine the first recording disk or not. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical disk recording / reproducing apparatus configured to record a signal on a disk with a laser beam irradiated from an optical pickup and perform a reproducing operation of the signal recorded on the disk with the laser beam.

  Disc players that use optical pickups to read signals recorded on discs have become widespread, but recently, in addition to playback functions, signals are recorded on discs using laser light emitted from optical pickups. An optical disc recording / reproducing apparatus configured so as to be able to be used has been commercialized.

  The optical disc recording / reproducing apparatus is configured to perform a focusing control operation for focusing laser light emitted from an optical pickup on a track on the disc and a tracking control operation for following the track. The focusing control operation and the tracking control operation are performed by the focus servo circuit and the tracking servo circuit, respectively. Such servo operation is generated by using a signal obtained from a photodetector incorporated in the optical pickup. The focus error signal and the tracking error signal are used for the configuration.

  There are various methods for performing a tracking control operation in an optical disc recording / reproducing apparatus. Generally, a tracking error signal obtained by selecting a combination of detection elements constituting a quadrant photodetector incorporated in an optical pickup. The push-pull method used in the case of a recording disc and the phase difference method used in the case of a read-only disc are used (see, for example, Patent Document 1).

  Further, the disc rotation speed control operation in the optical disc recording / reproducing apparatus is generally performed so that the linear velocity is constant. A control operation for keeping the linear velocity constant is performed by controlling a spindle motor that rotates the disk by a spindle servo. Such spindle servo operation is performed by a PLL circuit using a synchronization signal read from the disk, and the disk is rotated so that the linear velocity is constant by controlling the PLL circuit to be in a locked state. A control operation is performed.

  The synchronization signal read from the disk is extracted from a pit signal recorded as a pit when the disk is a reproduction-only disk, and is obtained from a meandering groove called a pregroove when the disk is a recording disk. It is configured to be extracted from the wobble signal. The spindle control operation using the pit signal is called pit servo, and the spindle control operation using the wobble signal is called wobble servo.

In addition, discs called DVDs include a read-only disc in which signals are recorded in pits and a recording disc in which pregrooves are formed, and the recording discs have different + and-standards. There are two types of discs. In an optical disc recording / reproducing apparatus that can use discs of different standards, it is necessary to discriminate the type of disc placed on the turntable, and the discriminating of such disc is detected by detecting the frequency of the wobble signal. There is a technique performed by this (for example, refer to Patent Document 2).
JP-A-8-87760 Japanese Patent Laid-Open No. 2002-230753

  The technology for detecting the type of disk by detecting the frequency of the wobble signal has a clock extraction circuit corresponding to each frequency in order to select each frequency, but it is not always possible to extract only the desired frequency. Absent. That is, since the RF signal reproduced from the disc can be obtained at various frequencies due to changes in the rotational characteristics of the disc, a noise signal is extracted as well as a signal that meets the recording disc standard. It will be. As a result, there is a problem that an accurate disc discrimination operation cannot be performed.

  The present invention is intended to provide an optical disc recording / reproducing apparatus that can solve such a problem.

  The present invention can use a read-only disc, a first recording disc and a second recording disc provided with different pregroove standards, and a tracking servo operation according to each disc standard and each disc. Filter characteristics to extract wobble signals of different frequencies obtained from pregrooves in an optical disk recording / reproducing apparatus equipped with a control circuit for controlling the rotational drive of the disk at a specified linear velocity using a synchronizing signal reproduced from A band pass filter circuit capable of changing the frequency, and setting the filter characteristic of the band pass filter circuit to a characteristic for extracting the wobble signal of the first recording disk, and the frequency of the wobble signal extracted by the band pass filter circuit Obtained from the wobble signal when is the frequency of the first recording disk. For the first recording by controlling the rotational drive so that the linear velocity is constant as the first recording disk by using the synchronizing signal and determining whether or not the rotational driving operation is locked. It is configured to determine whether or not it is a disk.

  The present invention can use a read-only disc, a first recording disc and a second recording disc provided with different pregroove standards, and a tracking servo operation according to each disc standard and each disc. Filter characteristics to extract wobble signals of different frequencies obtained from pregrooves in an optical disk recording / reproducing apparatus equipped with a control circuit for controlling the rotational drive of the disk at a specified linear velocity using a synchronizing signal reproduced from A band pass filter circuit capable of changing the frequency, and setting the filter characteristic of the band pass filter circuit to a characteristic for extracting the wobble signal of the first recording disk, and the frequency of the wobble signal extracted by the band pass filter circuit Obtained from the wobble signal when is the frequency of the first recording disk. For the first recording by controlling the rotational drive so that the linear velocity is constant as the first recording disk by using the synchronizing signal and determining whether or not the rotational driving operation is locked. Since it is determined whether or not it is a disc, it is possible to perform a more accurate discriminating operation than when disc discriminating operation is performed only by the frequency of the wobble signal.

  Further, the present invention detects the number of revolutions of the disc when it is determined to be in the locked state, and determines that the disc is the first recording disc when the number of revolutions is a predetermined number of revolutions. The operation can be performed.

Further, the present invention changes the filter characteristic of the bandpass filter circuit to a characteristic for extracting the wobble signal of the second recording disk when the wobble signal of the first recording disk is not extracted by the bandpass filter circuit, When the frequency of the wobble signal extracted by the bandpass filter circuit is the frequency of the second recording disk, the linear velocity is constant by using the synchronization signal obtained from the wobble signal as the second recording disk. The rotation drive control is performed so that the disk is a second recording disk by determining whether or not the rotation drive operation is in a locked state, so the disk is determined only by the frequency of the wobble signal. Compared with the case where the discriminating operation is performed, an accurate discriminating operation can be performed.

  Furthermore, the present invention detects the number of revolutions of the disc when it is determined to be in the locked state, and determines that the disc is the second recording disc when the number of revolutions is a predetermined number of revolutions. Disc determination operation can be performed.

  In the present invention, not only the frequency of the wobble signal but also the rotational speed control operation of the spindle motor is used to determine the type of the disk.

  FIG. 1 is a circuit diagram showing an embodiment of an optical disk recording / reproducing apparatus according to the present invention. In the figure, reference numeral 1 denotes a disk that is rotationally driven by a spindle motor 2, and a groove called a pre-groove is not formed on a reproducing disk, but a pre-groove is formed on a recording disk in a meandering manner. . That is, in the case of a recording disk, position information data indicating a recording position and a synchronization signal can be extracted from a wobble signal obtained from a pre-groove, and a recording / reproducing operation is performed using this signal. Has been. Further, the frequency of the wobble signal obtained from the pregroove on which the first recording disk and the second recording disk used in this embodiment are different from each other. The standard is set to 817 KHz, and the-system standard is set to 140 KHz.

  Reference numeral 3 denotes an optical pickup in which a laser diode 4 for irradiating the disk 1 with laser light and a photodetector 5 for receiving laser light reflected from the signal surface of the disk 1 are incorporated, and an objective lens (not shown) is provided. A focusing coil 6 for focusing the laser beam on the signal surface by displacing in the signal surface direction of the disk 1 and a tracking coil 7 for displacing the objective lens in the track direction so that the laser beam follows the signal track are incorporated. And is configured to be moved in the radial direction of the disk 1 by a pickup feed motor (not shown).

  Reference numeral 8 denotes a light detection signal output circuit that receives a signal obtained from the light detector 5 and generates various signals. A focus error signal obtained from the four-divided light detector that constitutes the light detector 5 is obtained. A focus error signal output terminal F for outputting, a tracking error signal output terminal T for outputting a tracking error signal, and a reproduction signal output terminal P for outputting a signal read from the disk 1, that is, a pit signal and a wobble signal are provided.

  Reference numeral 9 denotes a focus servo circuit which performs a focus servo operation by supplying a drive signal based on the focus error signal output from the focus error signal output terminal F of the light detection signal output circuit 8 to the focus coil 6. It is configured. A tracking servo circuit 10 performs a tracking servo operation by supplying a driving signal based on the tracking error signal output from the tracking error signal output terminal T of the light detection signal output circuit 8 to the tracking coil 7. It is configured.

Reference numeral 11 denotes an RF signal amplifying circuit for inputting and amplifying the RF signal, which is a signal output from the reproduction signal output terminal P of the photodetection signal output circuit 8, and for shaping the waveform and binarizing the signal. Is configured to output. Reference numeral 12 denotes the RF signal amplifier circuit 11.
Is a digital signal processing circuit to which a binarized signal is input, and is configured to perform demodulation of various signals.

  A system control circuit 13 receives the signal demodulated by the digital signal processing circuit 12 and performs various control operations in response to command signals output from a host device (not shown). A recording signal generation circuit 14 encodes a data signal, which is a recording signal output from the host device, into a signal suitable for performing a recording operation on the disk 1.

  Reference numeral 15 denotes a laser drive circuit whose operation is controlled by the system control circuit 13. When a data signal recording operation is performed, the recording signal encoded by the recording signal generation circuit 14 is input and the recording signal Is supplied to the laser diode 4, and a driving signal for performing the reproducing operation is supplied to the laser diode 4 during the reproducing operation.

  Reference numeral 16 denotes a spindle motor drive circuit in which the operation is controlled by the system control circuit 13 and a PLL circuit is incorporated, and is controlled so that the PLL circuit is locked by using a synchronization signal obtained from the disk 1. By doing so, a signal for driving the spindle motor 2 to rotate at a constant linear velocity is outputted. Reference numeral 17 denotes a rotation speed detection circuit that detects the rotation speed of the spindle motor 2 by counting the number of pulse signals that are input and the pulse signal generated along with the rotation of the spindle motor 2. The detected signal is output to the system control circuit 13.

  Reference numeral 18 denotes a band-pass filter circuit to which the wobble signal generated from the photodetection signal output circuit 8 is input through the RF signal amplifier circuit 11, and the filter characteristic is for the first recording by the switching control operation of the system control circuit 13. It is configured to be changed to a characteristic for extracting the wobble signal recorded on the disk and a characteristic for extracting the wobble signal recorded on the second recording disk. Reference numeral 19 denotes a binarization circuit that receives the signal extracted by the band-pass filter circuit 18 and binarizes the signal, and is configured to output a binarized signal to the system control circuit 13. .

  In such a configuration, the tracking error signal output terminal T provided in the light detection signal output circuit 8 has a push-pull tracking error when the recording disk is used by the control operation for the light detection signal output circuit 8 by the system control circuit 13. A signal is output, and a tracking error signal for phase difference is output when a read-only disc is used. When the type of the disc 1 is determined by the operation of the system control circuit 13, the signal processing operation conforming to the standards of each disc, that is, the first recording disc, the second recording disc, and the read-only disc is digitally performed. The signal processing circuit 12 and the like are configured to be in a state to be performed.

  Although the present invention is configured as described above, the operation will be described next. When the disk 1 is loaded into a disk loading section provided in the optical disk recording / reproducing apparatus, first, a setting operation is performed assuming that the disk 1 is a first recording disk. That is, the tracking error signal output terminal T of the light detection signal output circuit 8 is switched to a state in which a push-pull tracking error signal is output, and the filter characteristics of the bandpass filter circuit 18 are formed on the first recording disk. Is set to a characteristic for extracting the frequency of the wobble signal obtained from the pre-groove.

When the setting operation described above is performed, the optical pickup 3 is moved to a predetermined position on the inner circumference side of the disk 1, for example, a lead-in area where data indicating the position of a signal recorded on the disk is recorded and the spindle is moved. The motor 2 is driven to rotate at a predetermined rotational speed, that is, at a constant angular velocity. Such a rotational drive control operation with a constant angular velocity of the spindle motor 2 is performed by using a pulse signal output in accordance with the rotation of the spindle motor 2. However, such an operation is well known and will not be described. .

  In such a state, a driving signal for reproduction is supplied from the laser driving circuit 15 to the laser diode 4 and a focus control operation is performed. Such a focus control operation is performed by a servo operation of the focus servo circuit 9 based on an error signal output from a focus error signal output terminal F provided in the light detection signal output circuit 8.

  Such a focus control operation is performed by a servo operation of the focus servo circuit 9 based on an error signal output from a focus error signal output terminal F provided in the light detection signal output circuit 8. As is well known, a driving signal is supplied from the focus servo circuit 9 to the focusing coil 6 incorporated in the optical pickup 3 to control the displacement of the objective lens. Since such an operation may use a known technique, the description thereof is omitted.

  The focus control operation for focusing the laser beam on the signal surface of the disk 1 is performed by the above-described operation. When the focus control operation is normally performed, the tracking error signal output terminal provided in the light detection signal output circuit 8 is performed. The tracking control operation is performed using the push-pull tracking error signal output from T. Such tracking control operation is performed by the tracking incorporated in the optical pickup 3 in the direction of lowering the level of the push-pull tracking error signal output from the tracking error signal output terminal T provided in the light detection signal output circuit 8. This is done by supplying a drive signal from the tracking servo circuit 10 to the coil 7 and controlling the displacement of the objective lens.

  When the tracking control operation described above is performed, an operation for causing the laser beam to follow the signal track on the disk 1 is performed, so that the optical pickup 3 performs an operation for reading a signal or a wobble signal recorded on the disk 1. . The signal read by the optical pickup 3 is output from a reproduction signal output terminal P provided in the light detection signal output circuit 8. The reproduction signal output from the reproduction signal output terminal P is input to the RF signal amplifier circuit 11 to be amplified and binarized by a waveform shaping process. The binarized signal output from the RF signal amplifier circuit 11 is input to the digital signal processing circuit 12, and the digital signal processing operation by the digital signal processing circuit 12 is performed.

  On the other hand, the wobble signal extracted through the RF signal amplifier circuit 11 is input to the band pass filter circuit 18. The signal that has passed through the band-pass filter circuit 18 is input to the binarization circuit 19, binarized, and then input to the system control circuit 13. The system control circuit 13 can detect whether there is a signal passing through the band-pass filter circuit 18 by detecting the presence or absence of an input signal. When it is recognized that there is a signal passing through the band-pass filter circuit 18, the filter characteristic of the band-pass filter circuit 18 becomes a characteristic for extracting the wobble signal obtained from the first recording disk. Since it is set, the disc 1 can be recognized as the first recording disc. Therefore, in this case, the following processing is performed without changing the filter characteristics of the bandpass filter circuit 18.

If there is no signal binarized by the binarization circuit 19, it can be determined that there is no signal passing through the band-pass filter circuit 18 and that the disc is not the first recording disk. In this case, the switching control operation by the system control circuit 13 is performed, and the operation for changing the filter characteristic of the bandpass filter circuit 18 to the characteristic for extracting the wobble signal recorded on the second recording disk is performed. .

  The signal that has passed through the bandpass filter circuit 18 that has undergone such filter characteristic changing operation is input to the binarization circuit 19, binarized, and then input to the system control circuit 13. The system control circuit 13 can detect whether there is a signal passing through the band-pass filter circuit 18 by detecting the presence or absence of an input signal. When it is recognized that there is a signal passing through the band-pass filter circuit 18, the filter characteristic of the band-pass filter circuit 18 becomes a characteristic for extracting the wobble signal obtained from the second recording disk. Since it is set, the disc 1 can be recognized as the second recording disc. Therefore, in this case, the following processing is performed without changing the filter characteristics of the bandpass filter circuit 18.

  The wobble signal is extracted although the filter characteristic of the bandpass filter circuit 18 is set to the characteristic for extracting the wobble signal of the first recording disk and the characteristic for extracting the wobble signal of the second recording disk. If not, it can be determined that the disc 1 is not a recording disc but a read-only disc. In this case, the phase difference tracking error signal is switched to be output to the tracking error signal output terminal T of the light detection signal output circuit 8 and the signal processing operation by the digital signal processing circuit 12 is applied to the reproduction-only disk. The system control circuit 13 performs a control operation for setting a state for performing a reproduction operation of the recorded signal. As a result of such a control operation, the reproduction operation of the signal recorded on the disc 1 can be performed without any trouble.

  As described above, the operation related to the extraction operation of the wobble signal by the band-pass filter circuit 18 is performed. Next, the operation after the disc 1 is determined to be the first recording disc by the above-described operation will be described. .

  When the above-described detection processing operation is performed and it is determined that the disk 1 is the first recording disk, the synchronization signal is extracted from the signals input to the system control circuit 13. When the synchronization signal extraction operation is performed, the synchronization signal is input to the spindle motor drive circuit 16 and the spindle motor 2 is moved by the PLL lock operation by the PLL circuit incorporated in the spindle motor drive circuit 16. A control operation for keeping the linear velocity constant is performed.

  When such a control operation is performed, a determination operation as to whether or not the PLL lock operation of the spindle motor drive circuit 16 is performed is performed. In this state, if it is determined that the PLL circuit is locked, the disk 1 can be determined to be a recording disk. However, even if the wobble signal extraction operation by the bandpass filter circuit 18 described above is performed, it is not determined whether the disk 1 is the first recording disk or the second recording disk. That is, the frequency of the wobble signal obtained from the two recording disks is different according to the standard. However, when the PLL operation is performed by the synchronization signal obtained from the wobble signal, the PLL circuit is used for any disk. This is because they may be locked.

  Therefore, according to the present invention, when the PLL circuit incorporated in the spindle motor drive circuit 16 is in the PLL lock state, the rotation speed detection circuit 17 performs the operation of detecting the rotation speed of the spindle motor 2. When the rotation speed detection circuit 17 detects the rotation speed of the spindle motor 2, the detected rotation speed is input to the system control circuit 13.

When the rotation speed detected by the rotation speed detection circuit 17 is input to the system control circuit 13, the rotation speed data corresponding to each recording disk is stored in the system control circuit 13 and stored. An operation is performed for comparison with data stored in a memory circuit (not shown). In this case, the various control operations by the system control circuit 13 are set assuming that the disk 1 is the first recording disk, and therefore the rotation speed is set as data of the first recording disk. An operation for determining whether or not the number matches is performed.

  If it is determined that the rotational speed set as the data of the first recording disk matches with the determination operation, the type of the disk 1 is determined to be the first recording disk. The recording operation and the reproducing operation as the first recording disk are performed.

  If the rotational speed detected by the rotational speed detection circuit 17 by the above-described determination operation does not match the rotational speed set as the data of the first recording disk, the disk 1 is not the first recording disk. Can be determined.

  When the wobble signal is extracted after the filter characteristic of the bandpass filter circuit 18 is changed to the characteristic for extracting the wobble signal of the second recording disk, various setting operations by the system control circuit 13 are recorded in the second recording. It is configured to perform the above-described operation after the switching setting on the assumption of a disk for use. When this operation is performed and the PLL lock state of the PLL circuit is detected, the rotational speed of the spindle motor 2 is detected, and the rotational speed is stored in the memory circuit incorporated in the system control circuit 13. (2) An operation for determining whether or not the data matches the rotational speed data of the recording disk is performed. When the rotational speeds coincide with each other by such an operation, it is determined that the type of the disc 1 is the second recording disc, and thereafter, the recording operation and the reproducing operation as the second recording disc are performed. .

  If the rotational speed detected by the rotational speed detection circuit 17 by the above-described determination operation does not match the rotational speed set as the data for the second recording disk, the disk 1 is the second recording disk. It can be determined that it is not.

  Assuming that the disk 1 is the first recording disk or the second recording disk, the operation when the PLL operation for the constant linear velocity control by the spindle motor drive circuit 16 is locked is performed as described above. A case will be described in which the lock is not performed in either case. If the PLL operation is not locked even if the disk 1 is assumed to be a first recording disk and a second recording disk, it can be determined that the disk 1 is not a recording disk but a read-only disk. That is, since the spindle servo using the synchronization signal extracted from the wobble signal, that is, the wobble servo operation cannot be performed, it is determined that the disk 1 is a disk on which no wobble signal is recorded, that is, a read-only disk. I can do it.

  If it is determined that the disc is a read-only disc, an operation for changing various settings by the system control circuit 13 to a state in which the read-only disc is used is performed. As a result of performing the changing operation in this way, an operation for reproducing a signal recorded on the disc 1 is performed.

  If the number of rotations in the locked state does not match the number of rotations of the desired disk even though the PLL operation is locked, it is determined that the disk is a different recording disk and matches the characteristics of the disk. It is also possible to switch to a state in which a control operation is performed. Furthermore, in this case, it is possible to determine that the characteristics of the disk are unknown and to process it as an error.

It is a circuit diagram which shows one Example of the optical disk recording / reproducing apparatus based on this invention.

Explanation of symbols

1 disc
2 Spindle motor
3 Optical pickup
4 Laser diode
5 photodetectors
8 Photodetection signal output circuit
DESCRIPTION OF SYMBOLS 9 Focus servo circuit 10 Tracking servo circuit 11 RF signal amplifier circuit 12 Digital signal processing circuit 13 System control circuit 15 Laser drive circuit 16 Spindle motor drive circuit 17 Rotation speed detection circuit 18 Band pass filter circuit 19 Binary circuit

Claims (5)

A read-only disk, a first recording disk and a second recording disk with different pregroove standards can be used, and a tracking servo operation according to the standard of each disk and reproduction from each disk Filter characteristics can be changed to extract wobble signals of different frequencies obtained from pregrooves in an optical disc recording / reproducing apparatus equipped with a control circuit that controls the rotational drive of the disc at a prescribed linear velocity using a synchronizing signal. A band-pass filter circuit is provided, the filter characteristic of the band-pass filter circuit is set to a characteristic for extracting the wobble signal of the first recording disk, and the frequency of the wobble signal extracted by the band-pass filter circuit is the first recording Synchronization obtained from the wobble signal Whether the disc is the first recording disc or not is determined by controlling whether or not the disc is a first recording disc so that the linear velocity is constant and determining whether or not the rotational driving operation is locked. An optical disc recording / reproducing apparatus characterized by determining whether or not. 2. The disk according to claim 1, wherein when it is determined that the disk is in a locked state, the number of rotations of the disk is detected, and when the number of rotations is a predetermined number of rotations, it is determined that the disk is the first recording disk. Optical disc recording / reproducing apparatus. When the wobble signal of the first recording disk is not extracted by the bandpass filter circuit, the filter characteristic of the bandpass filter circuit is changed to the characteristic of extracting the wobble signal of the second recording disk, and the bandpass filter circuit When the frequency of the wobble signal extracted in this manner is the frequency of the second recording disk, the disk is rotated as a second recording disk by using the synchronization signal obtained from the wobble signal so that the linear velocity is constant. 2. The optical disc recording / reproducing apparatus according to claim 1, wherein it is determined whether or not the disc is a second recording disc by controlling and determining whether or not the rotational drive operation is in a locked state. . 4. The disk according to claim 3, wherein the number of rotations of the disk is detected when it is determined that the disk is in the locked state, and the disk is determined to be the second recording disk when the number of rotations is a predetermined number of rotations. Optical disc recording / reproducing apparatus. 4. The optical disc recording / reproducing apparatus according to claim 3, wherein when the wobble signal of the second recording disc is not extracted by the band-pass filter circuit, the disc is judged to be a reproduction disc.

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