JP2001202635A - Tracking controller and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize stabilization and speeding-up of the tracking pull-in after switching from a seeking operation to a tracking operation even when using an optical disk in an unrecorded state. SOLUTION: The tracking controller has a wobble detection BPF4 for extracting a wobble frequency component from a signal generated from reflected light of an optical disk 1, an amplitude detecting circuit 5 for detecting the quantity of amplitudes of the frequency component, a tracking error detection circuit 7 for generating a tracking error signal, and a brake processing control circuit 10 controlled to mute or attenuate the driver voltage of the moving direction which moves the scanning position of the beam spot to the disk radial direction, when detected that the scanning position of the beam spot crosses a track after detecting the moving direction to the radial direction of the disk of the beam spot to a track center and switching from a seeking operation to a tracking operation, based on the phase relation between the signal which binarized an amplitude detecting signal and the signal which binarized a tracking error signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a tracking control apparatus and method for performing tracking control of, for example, a recordable optical disk, and more particularly, to a DVD-RW, a DVD-R, and a DVD-R.
When using an optical disk such as a VD-RAM or the like in which data is recorded on a groove track or a land track and the groove or land is wobbled at a single frequency or a frequency near the frequency, tracking control to tracking control is performed. The present invention relates to a tracking control device and method for realizing a stable and high-speed pull-in.

[0002]

2. Description of the Related Art Conventionally, as controls of an optical pickup in an optical disk apparatus, tracking control for causing a light beam to follow an information track and seek control for moving the light beam to a desired information track have been performed.
These states are called a tracking control mode and a seek control mode, respectively.

FIG. 5 is a block diagram of a seek and tracking control system of a conventional read-only optical disk device. In FIG. 5, an optical pickup 102 focuses a laser beam on an optical disc 101, irradiates the optical beam spot so that the optical beam spot tracks a pregroove as a track, and picks up information from the reflected light.

[0004] A disc motor 116 drives the optical disc 101 clamped on a turntable provided on a rotating shaft.

[0005] The preamplifier circuit 103 amplifies the disk reproduction signal picked up by the optical pickup 102 and sends it to an RF detection circuit 104, a tracking error detection circuit 107, and a focus error detection circuit (not shown). In addition,
FIG. 5 shows only the seek and tracking control system, and a description of the focus error control system will be omitted.

[0006] The RF detection circuit 104 includes a preamplifier circuit 1
The RF signal of the disc reproduction signal supplied from the signal detector 03 is detected, and the RF signal is sent to the envelope detection circuit 5.

[0007] The envelope detection circuit 105 detects the envelope of the RF signal, and detects the detected signal (hereinafter, RF signal).
(Referred to as an envelope detection signal) to the binarization circuit 106.

[0008] The binarization circuit 106 binarizes the RF envelope detection signal, and sends the binarized signal (hereinafter referred to as an RF envelope detection binarization signal) to the brake processing control circuit 110.

On the other hand, the tracking error detection circuit 107
Detects a tracking error signal required for tracking control from the disk reproduction signal supplied from the preamplifier circuit 103, and sends the tracking error signal to the binarization circuit 108, the phase compensation circuit 109, and the track count circuit 112. The binarization circuit 108 binarizes the tracking error signal and sends the binarized signal (hereinafter, referred to as a tracking error binarized signal) to the brake processing control circuit 110.

[0010] The phase compensation circuit 109 compensates for the phase of the tracking error signal, and sends the tracking error signal after the phase compensation (hereinafter referred to as a phase compensation circuit output signal) to the brake processing control circuit 110.

Although the detailed configuration and operation will be described later, the brake processing control circuit 110 includes a binarizing circuit 1
06, the RF envelope detection binarized signal from the binarization circuit 06, the tracking error binarized signal from the binarization circuit 108, and
A tracking drive control signal used for tracking control is generated based on the phase compensation circuit output signal from the phase compensation circuit 109, and the tracking drive control signal is sent to one of the switched terminals a of the switch circuit 111. In addition,
In the following description, the tracking drive control signal output from the brake processing control circuit 110 will be appropriately referred to as a brake processing control circuit output signal.

A track count circuit 112 generates a track count number corresponding to the number of light beams crossing tracks on the optical disk 101 based on the tracking error signal, and stores the track count number in the CPU.
114 and to the seek control circuit 113.

The seek control circuit 113 calculates the number of tracks (the number of remaining tracks) from the current track to the target track after the seek from the track count number, and determines the optical pickup 1 at the time of seek determined according to the number of remaining tracks.
02 so that the moving speed (target speed) of the optical pickup 102 matches the moving speed of the optical pickup 102 (the speed at which the light beam moves in the disk radial direction) detected by a moving speed detecting device (not shown). A seek speed control signal for controlling a moving speed in a radial direction is generated. This seek speed control signal is supplied to the switch circuit 111
To the other switched terminal b.

The CPU 114 controls switching between tracking control and seek control. In the tracking control mode, one of the switched terminals a of the switch circuit 111 is switched.
Side (the tracking drive control signal side from the brake processing control circuit 110) is selected, and in the seek control mode, the other switched terminal b side of the switch circuit 11 (the seek speed control signal side from the seek control circuit 113) is selected. .

For example, when switching from the seek control mode to the tracking control mode, the CPU 114 switches between tracking control and seek control as follows. First, at the time of seek control, the CPU 114 performs switching control so that the other switched terminal b side of the switch circuit 111 (the seek speed control signal side from the seek control circuit 113) is selected. Here, the CPU 114 at the time of the seek control calculates the number of tracks (the distance to move the optical pickup 102) from the seek start position to the target track after the seek, and also calculates the track count number supplied from the track count circuit 112. On the basis of the,
If the number of tracks through which the light beam has passed since the start of the seek operation (the distance traveled by the optical pickup 102) is measured, and it is detected that the optical pickup 102 has moved to just before the target track by the seek operation, the switch is turned on. One of the switched terminals a of the circuit 111 (the tracking drive control signal from the brake processing control circuit 110) is selected. As a result, switching from seek control to tracking control is performed.

Conversely, when switching from the tracking control mode to the seek control mode, the CPU 114 controls the switching of the switch circuit 111 to the other switched terminal b side (the seek speed control signal side from the seek control circuit 113).
Thereafter, the CPU 114 calculates the number of tracks from the seek start position to the target track after the seek, and further measures the number of tracks through which the light beam has passed after starting the seek operation based on the track count. In addition, the seek control circuit 113 at this time calculates the number of remaining tracks, as described above, and detects the target speed of the optical pickup 102 at the time of seek determined according to the number of remaining tracks and the moving speed detecting device. A seek speed control signal for controlling the moving speed of the optical pickup 102 is generated so that the moving speed of the optical beam coincides with the moving speed of the optical beam, and the seek speed control signal is sent to the other switched terminal b of the switch circuit 111.

The tracking drive control signal or the seek speed control signal output from the switch circuit 111 is sent to the optical pickup drive circuit 115. The optical pickup drive circuit 115 generates a tracking drive signal for driving a tracking actuator of the optical pickup 102 based on the tracking drive control signal, and the tracking drive signal is emitted from the optical pickup 102 to the optical disc 101. The objective lens of the optical pickup 102 is moved in the radial direction of the disk so that the formed light beam spot is located on the center of the track (track center). Further, the optical pickup drive circuit 115 generates an optical pickup movement signal for moving the optical pickup 102 in the disk radial direction based on the seek speed control signal, and performs a seek operation based on the optical pickup movement signal.

FIG. 6 shows the relationship between the moving speed of the optical pickup 102 in the radial direction of the disk and the tracking error signal when switching from the seek control mode to the tracking control mode, for example.

In FIG. 6, in the seek control mode, the optical pickup 102 is moved in the radial direction of the disk at a constant speed, for example, by a seek speed control signal from the seek control circuit 113.
The moving speed of the optical pickup 102 is gradually reduced by a seek speed control signal from the seek control circuit 113. The tracking error signal in the seek control mode is, for example, a sinusoidal waveform signal due to the light beam spot crossing the track. Thereafter, when the light beam spot reaches just before the target track and is switched to the tracking control mode, the moving speed of the optical pickup 102 is reduced by the seek speed control signal from the seek control circuit 113. Further, the tracking error signal after switching to the tracking control mode becomes substantially constant.

Here, when the seek control is switched to the tracking control, for example, the optical pickup 102 is moved due to a variation in the moving speed of the optical pickup 102 (variation in the moving speed of the light beam spot with respect to the track) or a change in the timing at which the control is switched. 102 cannot perform tracking servo pull-in on the target track, and the tracking servo pull-in is performed after crossing several tracks beyond the target track, or the tracking servo cannot be pulled-in. In addition, the objective lens of the optical pickup 102 is largely displaced from the optical axis, and as a result, there arises a problem that the focus servo drops (does not work).

For this reason, for example, CD, DVD
When switching from seek control to tracking control when playing back a read-only disc such as, etc., the optical disc device uses the fact that the RF envelope detection signal has a phase difference of 90 degrees with the tracking error signal in the disc radial direction. The moving direction of the light beam spot with respect to the track is detected from the RF envelope detection signal and the tracking error signal, and the tracking drive signal in the moving direction is muted.

That is, in the optical disk apparatus shown in FIG. 5, the brake processing control circuit 110 detects the moving direction of the light beam spot with respect to the track from the RF envelope detection binarized signal and the tracking error binarized signal, and the moving direction. Then, a tracking drive control signal (brake processing control circuit output signal) for applying a mute (brake) to the tracking drive signal is generated, and the optical pickup drive circuit 115 is controlled by the brake processing control circuit output signal. .

As described above, in the conventional optical disk device,
When switching from seek control to tracking control, a mute (brake) is applied to the tracking drive signal in the moving direction of the light beam spot with respect to the track,
An attempt is made to solve the problems of the tracking servo pull-in error and the focus servo error due to the variation in the moving speed of the light beam spot with respect to the track and the change in the timing at which the control is switched.

FIG. 7 shows a specific block diagram of the brake processing control circuit 110 of FIG. 5 for generating a tracking drive control signal for muting (braking) the tracking drive signal when the tracking servo is pulled in as described above. The figure is shown. FIG. 8 shows a CD or DVD.
When playing back a read-only disc such as
After the optical disk device enters the tracking control mode from the seek control mode, when the light beam spot crosses the track from the disk inner circumference to the outer circumference,
8 shows waveforms at various points in the configuration shown in FIGS. further,
FIG. 9 shows that in the case of reproducing a read-only disc, after the optical disc apparatus of FIG. 5 enters the tracking control mode from the seek control mode, the light beam spot crosses the track from the disc outer side to the inner side. 8 shows waveforms at various points in the configuration of FIGS. 5 and 7 at the time.
The operation of the brake processing control circuit 110 shown in FIGS. 5 and 7 will be described with reference to FIGS.

In FIG. 7, a tracking error binarized signal obtained by binarizing the tracking error signal by the binarizing circuit 108 shown in FIG.
, The RF envelope detection signal is converted to a binarization circuit 1 shown in FIG.
At 06, the RF envelope detection binarized signal binarized is input. The terminal 133 receives a phase compensation circuit output signal from the phase compensation circuit 109 in FIG.

The tracking error binarized signal is sent to a clock input terminal of a latch circuit 125, and is input to a clock input terminal of a latch circuit 122 after being inverted by a knot circuit (inverting circuit) 121.

The RF envelope detection binarized signal is input to one input terminal of each of the two-input OR circuits 123 and 126, and after being inverted by the knot circuit 124, the data input terminal of the latch circuit 122 and the inverted reset signal. The terminal and the data input terminal of the latch circuit 125 and the inverted reset terminal are input.

Signal A output from the inverted data output terminal of latch circuit 122 (hereinafter referred to as latch output signal A)
Is input to the other input terminal of the two-input OR circuit 123,
The signal B output from the inverted data output terminal of the latch circuit 125 (hereinafter, referred to as a latch output signal B) is input to the other input terminal of the two-input OR circuit 126.

The signal obtained by the OR operation in the two-input OR circuit 123 is used as a switching control signal for the changeover switch 127, and the signal obtained by the OR operation in the two-input OR circuit 126 is switched. A switching control signal for the switch 128 is provided.

The changeover switch 127 sets the changeover control signal to L
(Low) level, it is turned on and the reference voltage V
ref is output. Similarly, the changeover switch 128 is turned on when the changeover control signal becomes L (low) level, and outputs the reference voltage Vref. The reference voltage Vr
ef is a predetermined constant value.

The output terminals of the changeover switches 127 and 128 are connected to a terminal 133 via a resistor R and an output terminal 134 of the brake processing control circuit 110.
Is also connected. The output signal of the terminal 134 is used as the brake processing control circuit output signal of the brake processing control circuit 110, and is sent to the switched terminal a of the switch circuit 111 in FIG.

That is, in the brake processing control circuit 110 having the configuration shown in FIG. 7, the RF envelope binary signal input to the terminal 132 is input at both rising and falling edges of the tracking error binary signal input to the terminal 131. A signal obtained by inverting the conversion signal is supplied to a latch circuit 122,
Latch at 125. When both of these latched signals are at the H (high) level and the latch is performed at the rising edge of the tracking error signal (when the latch output signal B is at the L level), the beam spot becomes It can be determined that the disk has moved to the outer peripheral side. At this time, as shown in FIG. 8, the brake processing control circuit 110 outputs a signal for controlling to mute most of the voltage (tracking drive signal) for driving the beam spot in the outer peripheral direction of the disk, as shown in FIG. Output as By doing so, the average value of the tracking drive signal generated by the optical pickup drive circuit 115 based on the output signal of the brake processing circuit drives the beam spot toward the inner circumference side of the disk. The brake will be applied.

When the signals latched by the latch circuits 122 and 125 are at the H level and the latch is performed at the falling edge of the tracking error signal (the latch output signal A becomes the L level). ), It can be determined that the beam spot is moving to the inner circumference side of the disk. At this time, the brake processing control circuit 11
At 0, as shown in FIG. 9, a signal for controlling to mute most of the voltage (tracking drive signal) for driving the beam spot in the inner circumferential direction of the disk is output as a brake processing control circuit output signal. By doing so, the average value of the tracking drive signal generated by the optical pickup drive circuit 115 based on the output signal of the brake processing circuit drives the beam spot to the outer periphery of the disk, and as a result, Brakes.

As described above, when the brake is applied, the relative movement speed of the beam spot in the disk radial direction is attenuated, and the tracking servo is applied. When the tracking servo is applied, the detection level of the RF level shown in FIG.
Is turned off, and normal tracking control (control by the output signal of the phase compensation circuit) is performed.

To summarize the above, in the conventional optical disc apparatus shown in FIG. 5, after switching from the seek control mode to the tracking control mode, if the beam spot crosses the track at the time of tracking pull-in, the brake is applied. Tracking is fast and stable.

[0036]

By the way, in recent years, D
Recordable optical disks such as VD-R and DVD-RW have appeared. These recordable optical disks are generally shipped to the market in an unrecorded state.

However, when recording is performed on a target track on the unrecorded optical disk, since the RF signal is not recorded, the brake processing control circuit 110 operates in the conventional optical disk apparatus shown in FIG. As a result, the driving voltage cannot be muted in the moving direction of the beam spot as described above, and there is a problem that the tracking pull-in cannot be stabilized and the speed cannot be increased.

The present invention has been made in view of the above-mentioned problem, and it is possible to stabilize tracking pull-in after switching from a seek operation to a tracking operation even in an unrecorded optical disk on which no RF signal is recorded. It is an object of the present invention to provide a tracking control device and method capable of realizing high speed and high speed.

[0039]

According to a first aspect of the present invention, there is provided a tracking control apparatus, wherein a groove-shaped or land-shaped track has a single frequency or a frequency in the vicinity thereof. A wobble frequency component extracting means for extracting a frequency component of the wobble from a signal obtained by a head scanning over the disc-shaped recording medium; Amplitude detection means for detecting the amplitude of the extracted wobble frequency component; and tracking error signal generation means for generating a tracking error signal for tracking from a signal obtained by scanning the head over the disk-shaped recording medium. The amplitude detection signal of the wobble frequency component and the tracking Based on the phase relationship between the error signal,
Moving direction detecting means for detecting a moving direction of the head scanning position in the disk radial direction with respect to the track center; and after switching from the seek operation to the tracking operation, the head scanning position crosses the track based on the moving direction detection result. Mute attenuating means for muting or attenuating the drive voltage in the moving direction for moving the head scanning position in the radial direction of the disk when detecting that.

According to a second aspect of the present invention, there is provided a tracking control method for solving the above-mentioned problems.
In a tracking control method for a disk-shaped recording medium in which groove-shaped or land-shaped tracks are wobbled at a single frequency or a frequency in the vicinity thereof, a signal obtained by scanning a head on the disk-shaped recording medium is obtained by: Extracting the frequency component of the wobble, detecting the amplitude of the extracted wobble frequency component, and performing tracking for tracking from a signal obtained by a head scanning over the disk-shaped recording medium. Generating an error signal;
Detecting the moving direction of the head scanning position with respect to the track center in the disk radial direction based on the phase relationship between the amplitude detection signal of the wobble frequency component and the tracking error signal, and switching from the seek operation to the tracking operation. And thereafter, when detecting that the head scanning position crosses the track based on the moving direction detection result, mute or attenuate a driving voltage in a moving direction for moving the head scanning position in a disk radial direction. .

That is, the present invention presupposes the use of a disk-shaped recording medium in which tracks are wobbled in a groove or land at a single frequency or a frequency in the vicinity of the track. By muting the drive voltage that moves the head scanning position in the radial direction of the disc, the head traversing operation of the head scanning position after switching from the seek operation to the tracking operation is suppressed, and the tracking pull-in time is shortened and stabilized. It is trying to make it.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a tracking control apparatus and method according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram of a seek and tracking control system of an optical disk device according to the present embodiment to which the tracking control device and method of the present invention are applied.

In FIG. 1, the optical disc 1 has a DV
An optical disc such as a D-RW, DVD-R, DVD-RAM, etc., on which data is recorded on a groove track or a land track and whose groove or land is wobbled at a single frequency or a frequency near the same. It is.

The optical pickup 2 focuses the laser light on the optical disk 1 and irradiates the light beam spot so that the light beam spot tracks the pregroove as a track.
A signal is generated from the reflected light. Further, the optical pickup 2 at the time of recording on the disc writes information on the track of the optical disc 1 by changing the laser emission intensity according to the recorded information.

The disk motor 16 rotates the optical disk 1 clamped on a turntable provided on a rotating shaft.

The preamplifier circuit 3 amplifies the signal generated by the optical pickup 2 from the reflected light of the recordable optical disk 1, and performs a wobble detection BPF (band pass filter) 4, a tracking error detection circuit 7, and a focus error detection (not shown). Send to circuit. Note that FIG. 1 shows only a seek and tracking control system, and a description of the focus error control system will be omitted.

The wobble detection BPF 4 extracts a wobble frequency component of a track on the optical disc 1 from the signal supplied from the preamplifier circuit 3 and extracts the extracted signal (hereinafter referred to as an extracted signal).
(Referred to as a wobble BPF output signal) to the amplitude detection circuit 5.

The amplitude detection circuit 5 detects the amplitude of the wobble BPF output signal and outputs the detected signal (hereinafter referred to as wobble BPF).
PF output amplitude detection signal) is sent to the binarization circuit 6.

The binarizing circuit 6 binarizes the wobble BPF output amplitude detection signal and sends the binarized signal (hereinafter, referred to as a wobble BPF output amplitude detection binarized signal) to the brake processing control circuit 10.

On the other hand, the tracking error detection circuit 7
A tracking error signal required for tracking control is detected from the signal supplied from the preamplifier circuit 3, and the tracking error signal is sent to a binarization circuit 8, a phase compensation circuit 9, and a track count circuit 12.

The binarizing circuit 8 binarizes the tracking error signal and sends the binarized signal (tracking error binarized signal) to the brake processing control circuit 10.

The phase compensation circuit 9 compensates the phase of the tracking error signal, and sends the tracking error signal (phase compensation circuit output signal) after the phase compensation to the brake processing control circuit 10.

Although the detailed configuration and operation will be described later, the brake processing control circuit 10 includes a wobble BPF output amplitude detection binary signal from the binarization circuit 6 and a tracking error binary signal from the binarization circuit 8. A tracking drive control signal used for tracking control is generated based on the conversion signal and the phase compensation circuit output signal from the phase compensation circuit 9, and the tracking drive control signal is connected to one of the switched terminals a of the switch circuit 11. Send to In the following description, the tracking drive control signal output from the brake processing control circuit 10 is also appropriately referred to as a brake processing control circuit output signal.

The track count circuit 12 calculates the track count number corresponding to the number of light beams crossing the tracks on the optical disk 1 based on the tracking error signal, similarly to the track count circuit 112 of FIG. The track count is generated and sent to the CPU 14 and the seek control circuit 13.

The seek control circuit 13 calculates the number of remaining tracks from the number of track counts similarly to the seek control circuit 113 in FIG. 5 described above, and determines the target of the optical pickup 2 at the time of seek determined in accordance with the number of remaining tracks. A seek speed control signal for controlling the moving speed of the optical pickup 2 in the radial direction of the disk is generated so that the speed and the speed of the light beam detected by the moving speed detecting device (not shown) move in the radial direction of the disk. I do. This seek speed control signal is sent to the other switched terminal b of the switch circuit 11.

The CPU 14 is the same as the CPU 11 shown in FIG.
In the same manner as in No. 4, switching control between tracking control and seek control is performed. In the tracking control mode, one of the switched terminals a of the switch circuit 11 (the tracking drive control signal from the brake processing control circuit 10) is selected. Then, in the seek control mode, the other switched terminal b side of the switch circuit 11 (the seek speed control signal side from the seek control circuit 13) is selected.

That is, for example, when switching from the seek control mode to the tracking control mode, the CPU 14 at the time of the seek control calculates the number of tracks from the seek start position to the target track after the seek, and based on the track count number. The number of tracks through which the light beam has passed since the start of the seek operation is measured, and if it is detected that the optical pickup 2 has moved to just before the target track by the seek operation, one of the switched terminals a of the switch circuit 11 (The tracking drive control signal side from the brake processing control circuit 10) is selected. As a result, switching from seek control to tracking control is performed.

Conversely, when switching from the tracking control mode to the seek control mode, the CPU 14 switches the switch circuit 11 to the other switched terminal b side (the seek control circuit 13).
To the seek speed control signal side). Thereafter, the CPU 14 calculates the number of tracks from the seek start position to the target track after the seek, and measures the number of tracks through which the light beam has passed since the start of the seek operation based on the track count. Further, the seek control circuit 13 at this time sets the optical speed so that the target speed of the optical pickup 2 at the time of seek determined according to the number of remaining tracks and the moving speed of the light beam detected by the moving speed detecting device coincide. A seek speed control signal for controlling the moving speed of the pickup 2 is generated, and the seek speed control signal is sent to the other switched terminal b of the switch circuit 11.

The tracking drive control signal or the seek speed control signal output from the switch circuit 11 is sent to the optical pickup drive circuit 15. The optical pickup drive circuit 15 generates a tracking drive signal for driving the tracking actuator of the optical pickup 2 based on the tracking drive control signal, similarly to the optical pickup drive circuit 15 of FIG. The objective lens of the optical pickup 2 is moved in the radial direction of the disc so that the light beam spot emitted from the optical pickup 2 and formed on the optical disc 1 is positioned on the track center (track center) by the drive signal. The optical pickup drive circuit 15
Is an optical pickup 2 based on a seek speed control signal.
An optical pickup movement signal for moving the optical pickup in the disk radial direction is generated, and a seek operation is performed by the optical pickup movement signal.

Here, in the optical disk device of the present embodiment, instead of the RF envelope signal in the read-only disk described with reference to FIGS. Utilizing the amplitude detection signal of the wobble BPF output signal possessed, the moving direction of the light beam spot with respect to the track is detected from the wobble BPF output amplitude detection signal and the tracking error signal, and the tracking drive signal in the moving direction is muted. The optical disc 1 is a recordable optical disc, such as a read-only disc such as a CD or a DVD.
Even if the optical disk has no signal recorded thereon, it is possible to stabilize and speed up the pull-in of the tracking servo after switching from the seek control mode to the tracking control mode.

That is, in the optical disk device of this embodiment, the wobble B
A tracking drive control signal (such as applying a mute (brake) to the tracking drive signal in the direction of movement of the light beam spot from the PF output amplitude detection binarized signal and the tracking error binarized signal. Brake processing control circuit output signal),
By controlling the optical pickup drive circuit 15 with the output signal of the brake processing control circuit, even if the optical disc 1 is a recordable optical disc (even if the optical disc 1 is in an unrecorded state), the light beam for the aforementioned track This solves the problems of tracking servo pull-in errors and focus servo errors due to variations in spot moving speed and fluctuations in control switching timing.

FIG. 2 shows the brake processing control circuit 10 of FIG. 1 for generating a tracking drive control signal for muting (braking) the tracking drive signal at the time of pull-in of the tracking servo in the present embodiment. A specific block diagram is shown. FIG. 3 shows a case where the optical beam drive of FIG. 1 enters the tracking control mode from the seek control mode and then the light beam spot moves the track to the inner circumferential side of the disk when using the recordable optical disk of the present embodiment. FIG. 3 shows waveforms at various points in the configuration shown in FIGS. Further, FIG. 4 shows that, when the recording type optical disk is reproduced, the optical beam spot moves the track from the disk outer peripheral side to the inner peripheral direction after the optical disk apparatus of FIG. 1 enters the tracking control mode from the seek control mode. FIG. 3 shows waveforms at various points in the configuration shown in FIGS. Using FIGS. 3 and 4, FIGS.
The operation of the brake processing control circuit 10 shown in FIG.

In FIG. 2, a tracking error signal obtained by binarizing the tracking error signal by the binarizing circuit 8 of FIG. 1 is input to a terminal 31 and a wobble BPF output amplitude detection is input to a terminal 32. A wobble BPF output amplitude detection binarized signal obtained by binarizing the signal with the binarization circuit 6 of FIG. 1 is input. The terminal 33 is connected to the phase compensation circuit 9 of FIG.
From the phase compensating circuit.

The tracking error binarized signal is sent to the clock input terminal of the latch circuit 25, similarly to the brake processing control circuit 10 in FIG. Input to the input terminal.

The wobble BPF output amplitude detection binarized signal is input to one input terminal of each of the two-input OR circuits 23 and 26. After being inverted by the knot circuit 24, the data input terminal of the latch circuit 22 and The data is input to the inverted reset terminal, the data input terminal of the latch circuit 25, and the inverted reset terminal.

The latch output signal A output from the inverted data output terminal of the latch circuit 22 is input to the other input terminal of the two-input OR circuit 23 as in the brake processing control circuit 10 of FIG. Latch output signal B output from the inverted data output terminal of
To the other input terminal.

The signal obtained by the OR operation in the two-input OR circuit 23 is used as a switching control signal for the changeover switch 27 similarly to the brake processing control circuit 10 in FIG. Is obtained as a switching control signal of the changeover switch 28.

The switch 27 is turned on and outputs the reference voltage Vref when the switch control signal is at the L (low) level, similarly to the brake processing control circuit 10 of FIG. Similarly, the changeover switch 28 sets the changeover control signal to L
(Low) level, it is turned on and the reference voltage V
ref is output. Note that the reference voltage Vref is a predetermined constant value.

The output terminals of these changeover switches 27 and 28 are connected to a resistor R as in the brake processing control circuit 10 of FIG.
And to the output terminal 34 of the brake processing control circuit 10. An output signal from the output terminal 34 is used as an output signal of the brake processing control circuit of the brake processing control circuit 10.
To the switched terminal a of the switch circuit 11 of FIG.

That is, in the brake processing control circuit 10 according to the present embodiment shown in FIG. 2, the wobble input to the terminal 32 is detected at both the rising and falling edges of the tracking error binarized signal input to the terminal 31. A signal obtained by inverting the BPF output amplitude detection binary signal is
The data is latched by the latch circuits 22 and 25. When the latched signals are both at the H level, if the inversion signal of the wobble BPF output amplitude detection binarized signal is latched at the rising edge of the tracking error signal (the latch output signal B becomes L level). When the level reaches the level), it can be determined that the beam spot has moved to the outer peripheral side of the disk. At this time, as shown in FIG. 3, the brake processing control circuit 10 outputs a signal for controlling so as to mute most of the voltage (tracking drive signal) for driving the beam spot toward the outer periphery of the disk, as shown in FIG. Output as a signal. By doing so, the average value of the tracking drive signal generated by the optical pickup drive circuit 15 based on the output signal of the brake processing circuit drives the beam spot toward the inner circumference side of the disk. The brake will be applied.

In this example, the method of muting the drive voltage at a predetermined timing in the brake processing control circuit 10 is adopted. However, this may be a method of attenuating the drive voltage in the moving direction. Even in this case, the same brake operation as described above can be realized.

When the signals latched by the latch circuits 22 and 25 are at the H level, latching of the inverted signal of the wobble BPF output amplitude detection binarized signal is performed at the falling edge of the tracking error signal. If this is done (when the latch output signal A becomes L level), it can be determined that the beam spot has moved to the inner circumference side of the disk. At this time, as shown in FIG. 4, the brake processing control circuit 10 outputs a signal for controlling so as to mute most of the voltage (tracking drive signal) for driving the beam spot in the inner circumferential direction of the disk, as shown in FIG. Output as By doing so, the average value of the tracking drive signal generated by the optical pickup drive circuit 15 based on the output signal of the brake processing circuit drives the beam spot to the outer periphery of the disc, and as a result, Brakes.

When the brake is applied as described above, the relative movement speed of the beam spot in the disk radial direction is attenuated, and the tracking servo is applied. When this tracking servo is applied, the wobble BPF output amplitude detection binarized signal shown in FIG.
7 and 28 are turned off, and normal tracking control (control by a phase compensation circuit output signal) is performed.

To summarize the above, in the optical disc apparatus of the present embodiment shown in FIG. 1, after switching from the seek control mode to the tracking control mode, when the tracking pull-in operation is performed on the unrecorded area of the recordable optical disc 1, When the spot crosses the track, the brake is applied, the tracking is fast, and it is possible to realize a stable pull-in.

Since tracks are wobbled in the recorded area of DVD-R and DVD-RW,
The brake processing control operation described above is performed in the DVD-
The same effect can be exerted in the recorded area of R and DVD-RW.

Finally, the present invention is not limited to the above-described embodiment described as an example, and other embodiments than the above-described embodiment may be used without departing from the technical idea of the present invention. It goes without saying that various changes can be made according to the design and the like.

That is, the present invention is not limited to the above-described optical disk, but can be applied to other disks as long as the disk-shaped recording medium has wobbled recording tracks.

[0079]

According to the first aspect of the present invention, there is provided a tracking control apparatus for extracting a wobble frequency component from a signal obtained by scanning a head on a disk-shaped recording medium, Means for detecting the amplitude of the signal, means for generating a tracking error signal from a signal obtained by scanning the head over the disk-shaped recording medium, and the phase of the amplitude detection signal and the tracking error signal of the wobble frequency component. Means for detecting the moving direction of the head scanning position relative to the track center in the disk radial direction based on the relationship, and detecting that the head scanning position crosses the track based on the moving direction detection result after switching from the seek operation to the tracking operation. Movement method for moving the head scanning position in the disk radial direction when detected And mute attenuating means for attenuating or attenuating the drive voltage of the disk drive, so that even in the case of an unrecorded disk-shaped recording medium on which no RF signal is recorded, the tracking pull-in after switching from the seek operation to the tracking operation is performed. Stabilization and high speed can be achieved.

According to a second aspect of the present invention, there is provided a tracking control method for detecting the amplitude of a wobble frequency component extracted from a signal obtained by scanning a head on a disk-shaped recording medium. A tracking error signal is generated from a signal obtained by the head scanning on the recording medium, and the head scanning position with respect to the track center is determined based on the phase relationship between the amplitude detection signal of the wobble frequency component and the tracking error signal. When the head scanning position is detected to cross the track after switching from the seek operation to the tracking operation, the moving direction in the disk radial direction is detected. By muting or attenuating the drive voltage,
Even in the case of an unrecorded disk-shaped recording medium on which no RF signal is recorded, it is possible to stabilize and speed up the tracking pull-in after switching from the seek operation to the tracking operation.

That is, according to the present invention, for example, a DVD
In an unrecorded area of a recordable optical disc such as -R, DVD-RW, etc., after switching from the seek control mode to the tracking control motor, even if the tracking is not pulled into the target track and the beam spot crosses the track, the focus is not obtained. There is no deviation, the tracking servo is pulled in a short time, and the access time can be shortened. Further, it is conceivable that the density of the optical disk will be further increased in the future. However, according to the present invention, the same effect can be obtained in the case of performing recording and reproduction on a high-density disk on which wobbled tracks and the like are formed. be able to.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a seek and tracking control system in a main part of an optical disc device which is an embodiment of a tracking control device and a tracking control method according to the present invention.

FIG. 2 is a block diagram showing a specific configuration of a brake processing control circuit of the optical disc device of the embodiment.

FIG. 3 shows a case where a recordable optical disk is used.
1 and 2 when the light beam spot crosses the track from the inner peripheral side to the outer peripheral side of the disk after the optical disk apparatus of the present embodiment enters the tracking control mode.
FIG. 5 is a waveform chart showing waveforms of respective units having the configuration of FIG.

FIG. 4 shows a case where a recordable optical disk is used.
FIGS. 1 and 2 show a state in which a light beam spot traverses a track from the disk outer peripheral side to the inner peripheral direction after the optical disk apparatus of the present embodiment enters the tracking control mode.
FIG. 5 is a waveform chart showing waveforms of respective units having the configuration of FIG.

FIG. 5 is a block diagram showing a schematic configuration of a seek and tracking control system as a main part of a conventional optical disc device.

FIG. 6 is a waveform diagram used to explain the relationship between the moving speed of the optical pickup in the disk radial direction and the tracking error signal when switching from the seek control mode to the tracking control mode.

FIG. 7 is a block diagram showing a specific configuration of a brake processing control circuit of a conventional optical disc device.

FIG. 8 shows a case where a conventional optical disc apparatus enters a tracking control mode and a light beam spot crosses a track from the inner circumference side to the outer circumference side of the disk when a conventional optical disk apparatus enters a tracking control mode. FIG. 3 is a waveform chart showing waveforms at various parts in the configuration of FIG. 2.

FIG. 9 shows a case where a conventional optical disc apparatus enters a tracking control mode and a light beam spot crosses a track from the outer circumference side to the inner circumference direction after the conventional optical disc apparatus enters a tracking control mode. FIG. 3 is a waveform chart showing waveforms at various parts in the configuration of FIG. 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Optical pickup, 3 ... Preamplifier circuit, 4 ... Wobble detection BPF, 5 ... Amplitude detection circuit,
6, 8 binarization circuit, 7 tracking error detection circuit, 9 phase compensation circuit, 10 brake processing control circuit,
11: switch circuit, 12: track count circuit, 1
3: seek control circuit, 14: CPU, 15: optical pickup drive circuit, 21, 24: knot circuit, 22, 2
5 latch circuit, 23, 26 2-input OR circuit, 27,
28 ... Changeover switch

Claims (2)

[Claims] In a tracking control apparatus for a disk-shaped recording medium in which groove-shaped or land-shaped tracks are wobbled at a single frequency or a frequency near the same, a head scans over the disk-shaped recording medium. A wobble frequency component extracting unit for extracting a frequency component of the wobble from the obtained signal; an amplitude detecting unit for detecting an amplitude amount of the extracted wobble frequency component; and a head scanning over the disk-shaped recording medium. A tracking error signal generating means for generating a tracking error signal for tracking from the obtained signal; and a head scan for a track center based on a phase relationship between the amplitude error detection signal of the wobble frequency component and the tracking error signal. The direction of movement of the position in the disk radial direction A moving direction detecting means for detecting, after switching from the seek operation to the tracking operation,
Mute attenuating means for muting or attenuating a drive voltage in a moving direction for moving the head scanning position in a disk radial direction when detecting that the head scanning position crosses the track based on the moving direction detection result. A tracking control device, characterized in that: 2. A tracking control method for a disk-shaped recording medium in which groove-shaped or land-shaped tracks are wobbled at a single frequency or a frequency in the vicinity thereof, wherein the head is scanned over the disk-shaped recording medium. Extracting a frequency component of the wobble from the obtained signal; detecting an amplitude of the extracted wobble frequency component; and a signal obtained by scanning the head over the disk-shaped recording medium, Generating a tracking error signal for tracking; and, based on a phase relationship between the amplitude error detection signal of the wobble frequency component and the tracking error signal, changing a moving direction of a head scanning position with respect to a track center in a disk radial direction. Detect step and seek operation to track After switching to the grayed operation,
Mute or attenuate a drive voltage in a moving direction for moving the head scanning position in a disk radial direction when detecting that the head scanning position crosses the track based on the moving direction detection result. Characteristic tracking control method.