JP2002216377A - Optical disk drive - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To measure an offset value of a tracking error signal, a folded portion due to an eccentric component,
Provided is an optical disk apparatus that can accurately measure an offset value of a tracking error signal even when a CAPA section exists or a recorded area and an unrecorded area are mixed in a disk. SOLUTION: When measuring an offset value of a tracking error signal, an eccentric folded portion is detected to cancel the waveform of the portion, and an address portion pre-pitted is detected based on the continuity of the tracking error signal to detect the portion. , The recorded area and the unrecorded area are discriminated, and the tracking offset values of the recorded area and the unrecorded area are measured independently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to tracking control in an optical disk device.

[0002]

2. Description of the Related Art In recent years, with the advent of digital versatile discs (hereinafter referred to as "DVDs"), large-capacity optical disc apparatuses have been attracting attention, and not only read-only optical disc apparatuses but also optical disc apparatuses have been receiving data. The development of optical disc devices capable of recording is also accelerating.

The configuration of a tracking control circuit in a general optical disk device will be described below. FIG. 10 is a block diagram of a conventional tracking control circuit. Figure 1
At 0, reference numeral 101 denotes an optical disk having tracks formed spirally or concentrically at a predetermined interval. 10
Reference numeral 2 denotes a spindle motor for rotating the optical disk 101 at a predetermined linear speed. Reference numeral 103 denotes an optical pickup, which includes a tracking actuator 104 for moving a light spot in a direction perpendicular to the track and a four-divided photodetector 1 for detecting a tracking error signal.
05, a two-segment photodetector 106 for detecting a focus error signal. As shown in the figure, the four-divided photodetector 105 is divided into four areas a to d by a track direction axis and an axis perpendicular to this axis. Then, the four divided signals a to d are processed to detect a tracking error signal.

[0004] 107, 108, 109 and 110 are I / V converters for current-to-voltage conversion of the detection current output from the 4-split detector 105, and 111 and 112 are detection outputs from the 2-split detector 106. It is an I / V converter for converting current to voltage.

[0005] Reference numerals 117 and 118 denote four-divided photodetectors 1 to obtain a push-pull tracking error signal.
05 is an adder for adding signals of two areas parallel to the track direction, and the adder 117 includes an area c and an area d.
, And the adder 118 adds the signals of the area a and the area b, respectively.

Reference numeral 113 denotes an adder for adding the outputs of the I / V converters 111 and 112 and the outputs of the adders 117 and 118. The adder 113 converts the optical signals received by the four-divided photodetector 105 and the two-divided photodetector 106 into light signals. A fully added RF signal is obtained by adding all the signals.

The output of the adder 113 is the peak value detection circuit 1
14 and the bottom value detection circuit 115, and the peak value detection circuit 114 outputs a continuous peak value of the full addition RF signal, while the bottom value detection circuit 115 outputs the continuous bottom value of the full addition RF signal. Is output.

Reference numeral 116 denotes a circuit for calculating the envelope signal (RFENV) of the total addition RF signal from the signals output from the peak value detection circuit 114 and the bottom value detection circuit 115. The envelope signal (RFENV) is sent to the controller 131. Is entered.

Reference numeral 119 denotes a balance adjusting circuit for changing the combined balance of the outputs of the adders 117 and 118.
Reference numeral 0 denotes a differential amplifier for calculating a push-pull signal from the output adjusted by the balance adjustment circuit 119.

Since the push-pull signal (TEDIF) output from the differential amplifier 120 contains a high-frequency component, the LPF 12 is controlled so that it can be handled in the servo band.
1 to detect only the low frequency component, and the controller 131
Is input as a push-pull tracking error signal (TEPP). The balance adjustment circuit 119 is adjusted by the controller 131 while observing the waveform of the push-pull tracking error signal (TEPP) while controlling the control signal (T
BALPP).

The address detector 122 detects an address signal included in the push-pull signal (TEDIF).
The wobble signal engraved along one track is detected.

Reference numerals 124 and 125 denote adders for adding signals in two areas diagonally opposite to each other in the track direction of the four-divided photodetector 105 in order to obtain a phase difference tracking error signal. The adder 125 adds the signal of the region a and the signal of the region c.

Reference numeral 126 denotes a comparator for binarizing the output of the adder 124 with a predetermined threshold, and 127 a comparator for binarizing the output of the adder 125 with a predetermined threshold.

Reference numeral 128 denotes a balance adjustment circuit for changing the composite balance of the outputs of the comparators 126 and 127.
Reference numeral 9 denotes a differential amplifier for calculating a push-pull signal from the output adjusted by the balance adjustment circuit 128.

Since the phase difference signal output from the differential amplifier 129 contains a high frequency component, only the low frequency component is detected by the LPF 130 so that it can be handled in the servo band, and the phase difference tracking is sent to the controller 131. Input as an error signal (TEPH). The balance adjustment circuit 128 is adjusted by the control signal (TBALPH) while the controller 131 observes the waveform of the phase difference tracking error signal (TEPH).

Reference numeral 132 denotes a traverse driving circuit for a traverse mechanism (not shown) for moving the optical pickup 103 along an axis substantially perpendicular to the track direction axis.
133 is a tracking drive circuit for controlling the tracking actuator 104 so that the light spot scans on the track.

Next, a description will be given of a tracking operation when an optical disk is reproduced by the optical disk apparatus configured as described above. Normally, in the tracking operation in the optical disk device, after turning on the focus control at the time of spin-up and before turning on the tracking control, the controller 131 outputs a tracking error signal (TEPH).
Is measured, the DC offset is canceled, and the tracking control is turned ON.

FIG. 11 shows a push-pull tracking error signal (TEP) when only the focus control is ON.
9 shows a waveform P). Tracking control O
Before N, a tracking offset control circuit (not shown) provided in the controller 131 integrates the push-pull tracking error signal (TEPP) with reference to the VREF voltage to measure a DC component from the VREF voltage. Is stored as an offset value. When turning on the tracking control, the controller 131
Tracking control is performed using a voltage obtained by adding the previously measured offset value to the VREF voltage as a reference voltage.

[0019]

However, the measurement of the offset value by the conventional tracking control circuit described above has the following problems.
FIG. 12A shows a state in which the tracking error signal has a folded portion due to the eccentric components of the optical disk 101 and the spindle motor 102.
As shown in (a), the waveform in the state where the folded portion has occurred is not a vertically symmetric waveform. This is VRE
When the integration is performed based on the F voltage, the offset value of the eccentric portion is counted so as to be on the + side, and there is a problem that an accurate offset value cannot be measured.

FIG. 12B shows a tracking error signal of a DVD-RAM, in which a laser spot is a pre-pitted address portion CA.
When passing through the PA section, it has a whisker-like waveform. Therefore, as in the case of FIG. 12 (a), if this is integrated on the basis of the VREF voltage, the offset value of the CAPA section cannot be accurately measured.

FIG. 12C shows a tracking error signal when a recording area and a non-recording area typified by a CD-RW disc cross a boundary between the recording area and the non-recording area in a disc in which the recording area and the unrecorded area coexist. In the recording area, the disk reflectance decreases, so that the amplitude of the tracking error signal decreases. In the unrecorded area, the disk reflectance increases compared to the recording area, and the tracking error signal increases. Therefore, the offset values of the recorded area and the unrecorded area are different from each other. However, if the integration is performed based on the VREF voltage without discriminating the area, the average value of each area is set as the offset value. There is a problem that it is not possible to measure a proper offset value.

The present invention has been made in view of the above-mentioned problems, and when measuring an offset value of a tracking error signal, a folded portion due to an eccentric component,
It is an object of the present invention to provide an optical disc apparatus capable of accurately measuring an offset value of a tracking error signal even when a CAPA section exists or a recorded area and an unrecorded area are mixed in a disc. I do.

[0023]

In order to solve the above-mentioned problems, an optical disk apparatus according to the present invention has an optical spot which has a diameter such that a tracking error signal indicating a displacement between a track on the optical disk and the optical spot becomes zero. An optical disc apparatus provided with a tracking drive means for moving the tracking error signal in a direction, a return detection means for detecting a return portion of the tracking error signal, and integrating the tracking error signal based on a detection result of the return detection means to obtain a reference voltage. And an offset value detecting means for detecting an offset value from the data.

Further, the optical disk device according to the present invention is
The loop-back detecting means determines and detects whether or not the input tracking error signal is a loop-back portion every cycle.

Further, the optical disk device according to the present invention comprises:
The loopback detection unit has a frequency detection unit that monitors the frequency of the tracking error signal, and a frequency comparison unit that compares a frequency value detected by the frequency detection unit with a predetermined threshold value. A portion in which the frequency value detected by the detecting means is slower than the predetermined threshold value is detected as a folded portion of the tracking error signal.

Further, the optical disk device according to the present invention comprises:
A low-pass filter for changing the peak value of the output waveform in accordance with the frequency of the tracking error signal; and a wave for comparing the peak value detected by the low-pass filter with a predetermined threshold value. High value comparing means, wherein a portion where the peak value detected by the low-pass filter means is larger than the predetermined threshold value is detected as a folded portion of the tracking error signal.

Further, the optical disk device according to the present invention comprises:
In an optical disc apparatus provided with a tracking driving means for moving a light spot in a radial direction so that a tracking error signal indicating a displacement between a track on a optical disc and a light spot becomes zero, the continuity of the waveform of the tracking error signal is reduced. Continuity detecting means for detecting, and offset value detecting means for detecting an offset value from a reference voltage by integrating the tracking error signal based on a detection result of the continuity detecting means. It is.

Further, the optical disk device according to the present invention comprises:
The continuity detecting means has at least two or more independent memory areas, and the independent memory area is at least a memory area for storing a waveform of one cycle of a tracking error signal, and It is characterized by being used as a memory area for performing an operation.

Further, the optical disk device according to the present invention comprises:
The continuity detecting means determines and detects the continuity of the input tracking error signal every cycle.

Further, the optical disk device according to the present invention comprises:
In an optical disc apparatus provided with a tracking driving means for moving a light spot in a radial direction such that a tracking error signal indicating a positional displacement between a track on an optical disc and a light spot becomes zero, an input tracking error signal on the optical disc is A recording / non-recording discriminating means for discriminating whether the signal belongs to a recording area or an unrecorded area, and integrating the tracking error signal based on a discrimination result of the recording / non-recording discriminating means. And an offset value detecting means for detecting an offset value from the reference voltage.

Also, the optical disc device according to the present invention
The offset value detecting means integrates a tracking error signal in a recording area of the optical disc to detect an offset value from a reference voltage, and a recording area offset value detecting means for integrating a tracking error signal in an unrecorded area of the optical disc. An unrecorded area offset value detecting means for detecting an offset value from the voltage, wherein the recorded / unrecorded discriminating means is provided when the input tracking error signal is a tracking error signal in a recording area of the optical disc. And outputting the tracking error signal to the recording area offset value detecting means. If the input tracking error signal is a tracking error signal in an unrecorded area of the optical disc, the tracking error signal is output to the unrecorded area offset value. Output to value detection means And it is characterized in Rukoto.

Further, the optical disk device according to the present invention comprises:
The recording / non-recording discriminating means discriminates between a recorded area and an unrecorded area based on the presence or absence of an RF envelope signal or a level difference of a reflected light amount.

[0033]

(Embodiment 1) Hereinafter, an optical disk apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. In the measurement of the offset value of the tracking error signal, the optical disc device according to the first embodiment of the present invention detects the eccentric fold portion and cancels the waveform of the fold portion due to the eccentricity to accurately measure the offset value. Things.

FIG. 1 is a block diagram showing an example of the configuration of the tracking control circuit according to the first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an optical disk, in which tracks are formed spirally or concentrically at a predetermined interval. 2
Is a spindle motor for rotating the optical disc 1 at a predetermined linear velocity.

Reference numeral 3 denotes an optical pickup, which includes a tracking actuator 4 for moving a light spot in a direction perpendicular to a track and a track, a four-division photodetector 5 for detecting a tracking error signal, and a two-division photodetector 6 for detecting a focus error signal. I have. As shown, the four-divided photodetector 5 is divided into four regions a to d by a track direction axis and an axis perpendicular to this axis. Then, the four divided signals a to d are processed to detect a tracking error signal.

Reference numerals 7, 8, 9, and 10 denote I / Os for converting the detection current output from the quadrant detector 5 from current to voltage.
V converters 11 and 12 are I / Vs for current-voltage conversion of a detection current output from the two-divided detector 6.
It is a converter.

Numerals 17 and 18 denote adders for adding signals of two areas parallel to the track direction of the four-divided photodetector 5 in order to obtain a push-pull tracking error signal. The signal of d
The adder 18 adds the signals of the area a and the area b, respectively.

Reference numeral 13 denotes an adder for adding the outputs of the I / V converters 11 and 12 and the outputs of the adders 17 and 18.
Thus, a total addition RF obtained by adding all the optical signals received by the four-split photodetector 5 and the two-split photodetector 6
Get the signal. The output of the adder 13 is a peak value detection circuit 14
And the bottom value detection circuit 15, and the peak value detection circuit 14 outputs a continuous peak value of the full addition RF signal, while the bottom value detection circuit 15 outputs a continuous bottom value of the full addition RF signal. Is done.

Reference numeral 16 denotes a differential amplifier for calculating an envelope signal (RFENV) of the total addition RF signal from the signals output from the peak value detection circuit 14 and the bottom value detection circuit 15, and the envelope signal (RFENV) is used as a controller. 31 is input.

Reference numeral 19 denotes a balance adjustment circuit for changing the combined balance of the outputs of the adders 17 and 18, and reference numeral 20 denotes a differential amplifier for calculating a push-pull signal from the output adjusted by the balance adjustment circuit 19.

Since the push-pull signal (TEDIF) output from the differential amplifier 20 contains a high-frequency component, only the low-frequency component is detected by the LPF 21 so that it can be handled in the servo band. It is input as a push-pull tracking error signal (TEMPP). The balance adjustment circuit 19 is adjusted by the controller 31 by the push-pull tracking error signal (T
While observing the waveform of EPP, the control signal (TBARP)
P).

The address detector 22 detects an address signal included in the push-pull signal (TEDIF), and the wobble detector 23 detects a wobble signal engraved along the track of the optical disk 1. It is.

Numerals 24 and 25 are adders for adding signals of two areas diagonally opposite to each other in the track direction of the four-divided photodetector 5 in order to obtain a phase difference tracking error signal. And the signal of the region d, and the adder 25 adds the signal of the region a and the signal of the region c.

Reference numeral 26 denotes a comparator for binarizing the output of the adder 24 with a predetermined threshold, and reference numeral 27 denotes a comparator for binarizing the output of the adder 25 with a predetermined threshold. 28 is a comparator 2
A balance adjustment circuit for changing the combined balance of the outputs of the circuits 6 and 27, and 29 is a differential amplifier for calculating a push-pull signal from the output adjusted by the balance adjustment circuit 28.

Since the phase difference signal output from the differential amplifier 29 contains a high frequency component, only the low frequency component is detected by the LPF 30 so that it can be handled in the servo band, and the phase difference tracking signal is sent to the controller 31. Input as an error signal (TEPH). The balance adjustment circuit 28 is adjusted by the control signal (TBALPH) while the controller 31 observes the waveform of the phase difference tracking error signal (TEPH).

Reference numeral 32 denotes a traverse drive circuit for a traverse mechanism (not shown) for moving the optical pickup 3 along an axis substantially perpendicular to the track direction axis. 33
Is a tracking drive circuit for controlling the tracking actuator 4 so that the light spot scans on the track. 34 is provided in the controller 31;
This is a tracking offset control circuit that detects a waveform of a folded portion due to eccentricity, cancels the waveform of the portion, and measures an offset value.

Reference numeral 35 denotes a track cross detector which inverts and outputs a tracking error signal output from the LPF 21 or LPF 30 at a timing crossing the VREF voltage, and a push-pull tracking error signal (TEPP).
In the case of, TCR1 and the phase difference tracking error signal (T
In the case of EPP), it is input to the tracking offset control circuit 34 as TCR2.

Next, the internal configuration of the tracking offset control circuit 34, which is a feature of the present invention, will be described in more detail with reference to FIG. FIG. 2 is a block diagram showing an example of an internal configuration of the tracking offset control circuit 34 according to the second embodiment of the present invention. 2 indicates the track cross detector 35 shown in FIG.

In FIG. 2, reference numeral 301 denotes a return detector for detecting an eccentric return portion of the optical disk, and the time from the rising edge to the rising edge of the output signal of the track cross detector 35 or the time from the falling edge to the falling edge. Frequency detector 303 for measuring
And a frequency comparator 304 that compares a value measured by the frequency detector 303 with a predetermined threshold value (th1).

Reference numeral 302 denotes a push-pull tracking error signal (TEPP) which is integrated with respect to the VREF voltage every period (for example, a period from the rising edge to the rising edge of the track cross signal 35). Output frequency comparator 3
An offset value detector that determines whether or not to add the integral value to the offset value every cycle based on the comparison result of No. 04 and detects the offset value. Here, a description will be given of a case where an integral value of a waveform is calculated for each cycle and a determination is made as to whether or not to add the integrated value to an offset value.
The integrated value of the waveform may be calculated at regular intervals, and it may be determined whether or not to add the integrated value to the offset value.

Next, a description will be given of a tracking control operation when an optical disk is reproduced by the optical disk apparatus of the present invention configured as described above, with reference to FIG. FIG.
6 is a timing chart for explaining a tracking control operation of the optical disc device according to the first embodiment of the present invention.

The push-pull tracking error signal (T
3 (a) is output, and the track cross detector 35 compares the push-pull tracking error signal (TEPP) with the VREF voltage, and the push-pull tracking error signal (TEPP) is If it is larger, an "H" level is output. As shown in FIG. 3B, the TCR 1 output from the track cross detector 35 has the same period of the push-pull tracking error signal (TEPP) except for the eccentric fold, but the TCR 1 returns to the fold. The cycle gradually becomes slower as approaching. At the turning point, the push-pull tracking error signal (TEPP) does not cross the VREF voltage and the "H" level is output all the time.

FIG. 3C shows a waveform immediately before the turning point, and the frequency detector 303 of the turning detector 301 has the rising edge to the rising edge of the output signal of the track cross detector 35, or Measure the time from the falling edge to the falling edge,
The measured count value is compared with a predetermined threshold value (th1) by the frequency comparator 304. FIG. 3 (d)
FIG. 3B shows a comparison result between the count value for the waveform shown in FIG. 3C measured by the frequency detector 303 and a predetermined threshold value (th1). As shown in FIG. The count value of the unit 303 does not reach the preset threshold value (th1). Therefore, the aliasing detector 301 determines that the waveform is a normal waveform, and sends a signal to the offset value detector 302 indicating that the waveform for one cycle shown in FIG. Output.

Next, when the offset value detector 302 receives the signal indicating the normal waveform output from the aliasing detector 301, the offset value detector 302 generates a push-pull tracking error signal for one cycle with respect to the VREF voltage for the waveform. The integral value of (TEPP) is added to the offset value.

On the other hand, FIG. 3E shows the waveform at the turning point, and the count value measured by the frequency detector 303 of the turning detector 301 is set in advance as shown in FIG. Threshold value (th1). Therefore, the aliasing detector 301 determines that the waveform is an abnormal waveform, and outputs a signal to the offset value detector 302 indicating that the one-cycle waveform shown in FIG. I do.

When the offset value detector 302 receives the signal indicating the abnormal waveform output from the aliasing detector 301, the offset value detector 302 has a push-pull tracking error signal for one cycle based on the VREF voltage for the waveform. The integrated value of (TEPP) is not added to the offset value.

Note that the predetermined threshold value (th
The value of 1) can be freely set in advance by a user or the like, for example, by setting the value to be approximately 1.5 to 2 times the count value of the aliasing detector 301 for the waveform for one cycle immediately before. it can.

As described above, according to the optical disk device of the first embodiment of the present invention, in measuring the offset value of the tracking error signal, the eccentric fold is detected in advance, and the waveform of the eccentric fold is canceled. Thus, an accurate tracking offset value can be measured.

Note that the return detector 301 of the optical disk device according to the first embodiment of the present invention
3 and a frequency comparator 304.
According to 04, the frequency value which is the count value of the frequency detector 303 is compared with a predetermined threshold value, and if the frequency value is larger than the predetermined threshold value, the waveform is detected as an eccentric folded portion of the optical disk. However, for example, the loopback detector 301 changes the peak value of the output waveform in accordance with the frequency of the tracking error signal, a peak value detected by the low-pass filter, and a predetermined threshold value. And a peak value comparator for comparing the peak value of the push-pull tracking error signal output from the low-pass filter with a predetermined threshold value. If it is larger than the threshold value, the waveform may be detected as an eccentric folded portion of the optical disk.

In the description of the tracking offset control circuit 34 according to the first embodiment of the present invention, measurement of the offset value of the push-pull tracking error signal (TEPP) has been described as an example, but the phase difference tracking error signal (TEPH) has been described. Even when the offset value is measured, by performing the same operation, it is possible to detect the eccentric fold portion of the optical disc every cycle and cancel the waveform of the eccentric fold portion, An accurate tracking offset value can be measured.

(Embodiment 2) Hereinafter, an optical disk device according to Embodiment 2 of the present invention will be described with reference to FIGS. In the optical disc device according to the second embodiment of the present invention, in measuring the offset value of the tracking error signal, by monitoring the continuity of the waveform of the tracking signal, the optical disc apparatus is pre-pitted in advance like a CAPA section of a DVD-RAM. An accurate offset value is detected by detecting an address portion and canceling the waveform of the pre-pitted address portion.

FIG. 4 is a block diagram for explaining an example of the structure of the optical disk device according to the second embodiment of the present invention. In FIG. 4, since the configuration other than the tracking offset control circuit 41 is the same as that of the optical disk device according to the first embodiment described with reference to FIG. Omitted.

FIG. 5 is a block diagram showing an example of the internal configuration of the tracking offset control circuit 41 according to the second embodiment of the present invention. The tracking offset control circuit 3 according to the first embodiment described with reference to FIG.
The same components as those in the configuration of No. 4 are denoted by the same reference numerals, and description thereof is omitted.

Reference numeral 401 denotes a continuity detector which stores a waveform for one cycle of the push-pull tracking error signal (TEPP) and detects continuity of the stored waveform, and a memory for storing a waveform for one cycle. It has an area (not shown) and a memory area (not shown) as an operation area for detecting continuity. By providing at least a memory area for storing a waveform for one cycle and a memory area as an operation area for detecting continuity, storage of a waveform for one cycle and detection of continuity are performed. The operations can be performed simultaneously, and the processing speed for detecting continuity can be improved.

The reference numeral 402 designates an integration of the push-pull tracking error signal (TEEP) with respect to the VREF voltage every one cycle (for example, a period from the rising edge to the rising edge of the track cross signal 35), and the folding detector 301, And an offset value detector that determines whether or not to add the integral value to the offset value every cycle based on the detection result output from the continuity detector 401 and detects the offset value. Here, a description will be given of a case where an integral value of a waveform is calculated for each cycle and a determination is made as to whether or not to add the integrated value to an offset value.
The integrated value of the waveform may be calculated at regular intervals, and it may be determined whether or not to add the integrated value to the offset value.

Next, a tracking control operation when an optical disk is reproduced by the optical disk apparatus of the present invention configured as described above will be described with reference to FIG. FIG.
9 is a timing chart for explaining an example of a tracking control operation of the optical disc device according to the second embodiment of the present invention.

The push-pull tracking error signal (T
EPP) outputs the waveform shown in FIG.
The track cross detector 35 compares the push-pull tracking error signal (TEPP) with the VREF voltage, and outputs an “H” level if the push-pull tracking error signal (TEPP) is larger. Note that the processing for the waveform of the eccentric folded portion shown in FIG. 6 is the same as the tracking control operation according to the first embodiment described with reference to FIG.

The push-pull tracking error signal (TEPP) shown in FIG. 6A also includes a waveform when passing through a pre-pitted address portion like a CAPA section of a DVD-RAM. The output of the track cross detector 35 when passing through the pre-pitted address portion uses a chattering elimination function for the binarized waveform of the pre-pitted address portion shown in FIG. Thus, it is shaped like the waveform shown in FIG.

The continuity detector 401 stores the push-pull tracking error signal (TEPP) for each cycle,
From the stored continuous change degree of the waveform for each cycle, a waveform for one cycle including an address portion pre-pitted is detected. That is, the continuity detector 401 first stores a waveform for one cycle in a memory area of the continuity detector 401, and differentiates the push-pull tracking error signal (TEPP) for the one cycle by using FIG. (D)
To obtain the differential waveform. Next, this differentiated waveform is compared with a preset threshold value (th2), and if there is a waveform larger than the preset threshold value (th2), that portion is regarded as an address portion pre-pitted. judge. Further, the continuity detector 401 outputs the determined waveform position of the pre-pit address portion to the offset value detector 402.

The offset value detector 402 provides an invalid section (FIG. 6) between the leading and trailing edges of the waveform position of the pre-pitted address portion determined by the continuity detector 401.
As (e)), the offset value is detected.

The predetermined threshold value (th
The value of 2) can be freely set in advance by a user or the like, for example, by setting the value to be approximately の of the amplitude of the differential waveform.

As described above, according to the optical disk device of the second embodiment of the present invention, the pre-pitted address portion is detected by monitoring the continuity of the waveform, as in the case of the CAPA of a DVD-RAM. By canceling the waveform of the pre-pitted address portion, the tracking offset value can be accurately detected.

Further, the continuity detector 401 of the optical disk device according to the second embodiment of the present invention has been described as having two independent memory areas, but is not limited to this. If it has an area, it is possible to simultaneously store the waveform for one cycle and detect the continuity, thereby improving the processing speed for detecting the continuity.

(Embodiment 3) Hereinafter, an optical disk apparatus according to Embodiment 3 of the present invention will be described with reference to FIGS. The optical disc device according to Embodiment 3 of the present invention determines a recorded area and an unrecorded area on a disc in which a recorded area and an unrecorded area are mixed, such as a CD-RW, in measuring the offset value of the tracking error signal,
The tracking offset values of the recorded area and the unrecorded area are separately measured using the result, thereby detecting an accurate offset value for each area.

FIG. 7 is a block diagram for explaining an example of the structure of the optical disk device according to the third embodiment of the present invention. In FIG. 7, since the configuration other than the tracking offset control circuit 71 is the same as that of the optical disc device according to the first embodiment described with reference to FIG. Omitted.

FIG. 8 is a block diagram showing an example of the internal structure of tracking offset control circuit 71 according to the third embodiment of the present invention. In FIG. 8, reference numeral 501 designates whether the input tracking error signal is a tracking error signal of a recording area on an optical disk or a tracking error signal of an unrecorded area, and determines the tracking error signal of the recording area as a recording area offset value. The detector 502 is a recording / non-recording discriminator that outputs a tracking error signal of an unrecorded area to the unrecorded area offset value detector 503. Reference numeral 502 denotes a recording area offset value detector that integrates a tracking error signal in the recording area of the optical disk with reference to the VREF voltage and detects an offset value of the tracking error signal in the recording area. 503
Is an unrecorded area offset value detector that integrates a tracking error signal in an unrecorded area of the optical disc with reference to the VREF voltage and detects an offset value of the tracking error signal in the unrecorded area.

Next, a tracking control operation when an optical disk is reproduced by the optical disk apparatus of the present invention configured as described above will be described with reference to FIG. FIG.
9 is a timing chart for explaining an example of a tracking control operation of the optical disc device according to the third embodiment of the present invention.

A tracking error signal in an optical disc such as a CD-RW in which a recorded area and an unrecorded area coexist is such that a push-pull tracking error signal (TEPP) has a large signal amplitude in an unrecorded area and a small signal amplitude in a recorded area. (See FIG. 9A). Also, an envelope signal (RFENV) on an optical disc such as a CD-RW in which a recorded area and an unrecorded area are mixed.
As shown in FIG. 9B, in the unrecorded area,
Since there are no pits on the optical disc, it indicates the amount of reflection on the mirror surface, and in the recording area, since there are pits on the optical disc, the amount of reflection is lower than the amount of reflection on the mirror surface. .

Therefore, the recorded / unrecorded discriminator 501 is
The input envelope signal (RFENV) is binarized by a recording / unrecorded area detection threshold (th3) to generate a switching signal (see FIG. 9C), and the switching is performed based on the generated switching signal. When the signal is "H", an unrecorded area is selected, and when the signal is "L", a recorded area is selected.

As a result, the push / pull tracking error signal (TEPP) in the recorded area and the unrecorded area is accurately separated by the recorded / unrecorded discriminator 501, and the push / pull tracking error signal (TEPP) in the unrecorded area is determined.
(See FIG. 9D) The unrecorded area offset value detector 5
03, the push-pull tracking error signal (TEPP) of the recording area (see FIG. 9E) is output to the recording area offset detector 502.

Thereafter, the push-pull tracking error signal (TEPP) for the recorded area and the unrecorded area is processed separately, and the offset value for each of the recorded area and the unrecorded area is measured.

As described above, according to the optical disc apparatus of the third embodiment of the present invention, when measuring the offset value of the tracking error signal, the recording area of the disc where the recording area and the unrecorded area coexist, such as CD-RW, is measured. By determining the tracking offset values of the recorded area and the unrecorded area separately using the result, an accurate offset value for each area can be measured.

Although the tracking offset control circuit 71 according to the third embodiment of the present invention has been described in which the recording area and the unrecorded area are discriminated and the offset value is detected, the tracking offset control circuit 71
Further, the return detector 301 and the continuity detector 402 described in the first and second embodiments may be provided, and a more accurate offset value can be measured.

[0084]

As described above, according to the optical disc apparatus of the present invention, the return detecting means for detecting the return portion of the tracking error signal, and the tracking error signal is integrated based on the detection result of the return detecting means. With the provision of the offset value detecting means for detecting the offset value from the reference voltage, the waveform of the folded portion due to the eccentricity can be canceled, and the offset value can be accurately measured.

Further, according to the optical disk apparatus of the present invention, continuity detecting means for detecting the continuity of the tracking error signal waveform, and integrating the tracking error signal based on the detection result of the continuity detecting means. And an offset value detecting means for detecting an offset value from the reference voltage, it is possible to detect a pre-pitted address portion, such as a CAPA of a DVD-RAM, , The offset value can be accurately measured.

Further, according to the optical disc apparatus of the present invention, the recording / non-recording discrimination for discriminating whether the input tracking error signal is for a recording area or an unrecorded area on the optical disc. Means, and offset value detecting means for integrating the tracking error signal and detecting an offset value from a reference voltage based on the result of the discrimination by the recorded / unrecorded discriminating means.
It is possible to determine the recording area and the unrecorded area in a disc in which the recording area and the unrecorded area are mixed, such as D-RW, and separately measure the tracking offset values of the recorded area and the unrecorded area. Can be measured accurately.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a configuration of an optical disc device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating an example of an internal configuration of a tracking offset control circuit according to the first embodiment of the present invention.

FIG. 3 is a timing chart for explaining a tracking control operation of the optical disc device according to the first embodiment of the present invention.

FIG. 4 is a block diagram illustrating an example of a configuration of an optical disc device according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing an example of an internal structure of a tracking offset control circuit according to Embodiment 2 of the present invention.

FIG. 6 is a timing chart for explaining a tracking control operation of the optical disc device according to the second embodiment of the present invention.

FIG. 7 is a block diagram illustrating an example of a configuration of an optical disc device according to a third embodiment of the present invention.

FIG. 8 is a block diagram illustrating an example of an internal structure of a tracking offset control circuit according to a third embodiment of the present invention.

FIG. 9 is a timing chart illustrating a tracking control operation of the optical disc device according to the third embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a conventional optical disk device.

FIG. 11 is a timing chart illustrating a tracking error signal.

FIG. 12 is a diagram illustrating types of tracking error signals.

[Explanation of symbols]

Reference Signs List 1 optical disk 2 spindle motor 3 optical pickup 4 tracking actuator 5 4-split photo detector 6 2-split photo detector 7, 8, 9, 10, 11, 12 I / V converter 13, 17, 18, 24, 25 adder 14 peak value detection Circuit 15 Bottom value detection circuit 16, 20, 29 Differential amplifier 19, 28 Balance adjustment circuit 21, 30 LPF 22 Address detection unit 23 Wobble detector 26, 27 Comparator 31 Controller 32 Traverse drive circuit 33 Tracking drive circuit 34, 41 , 71 tracking offset control circuit 35 track cross detector 301 loopback detector 302, 402 offset value detector 303 frequency detector 304 frequency comparator 401 continuity detector 402 offset value detector 501 recording / Unrecorded discriminator 502 Recorded area offset value detector 503 Unrecorded area offset value detector

Claims (10)

[Claims] 1. An optical disc apparatus comprising: a tracking drive unit for moving a light spot in a radial direction such that a tracking error signal indicating a positional deviation between a track on an optical disc and a light spot becomes zero. Folding detection means for detecting a folding part, and offset value detection means for integrating the tracking error signal and detecting an offset value from a reference voltage based on a detection result of the folding detection means, Optical disk device. 2. The optical disc device according to claim 1, wherein the return detecting unit determines, on a cycle basis, whether or not the input tracking error signal is a return portion, and detects the return. Optical disk device. 3. The optical disk device according to claim 1, wherein the return detecting unit monitors a frequency of the tracking error signal, and a frequency value detected by the frequency detecting unit. And a frequency comparison unit that compares the predetermined threshold value, and a frequency value detected by the frequency detection unit is detected as a loopback portion of the tracking error signal, a portion that is later than the predetermined threshold value, An optical disc device characterized by the above-mentioned. 4. The optical disk device according to claim 1, wherein the return detecting unit changes a peak value of an output waveform in accordance with a frequency of the tracking error signal; A peak value comparing unit that compares a peak value detected by the low-pass filter unit with a predetermined threshold value, and a part where the peak value detected by the low-pass filter unit is larger than the predetermined threshold value. An optical disc device, which detects a tracking error signal as a folded portion. 5. An optical disc apparatus comprising: a tracking drive unit for moving a light spot in a radial direction such that a tracking error signal indicating a positional deviation between a track on an optical disc and a light spot becomes zero. Continuity detecting means for detecting continuity of the waveform, and offset value detecting means for integrating the tracking error signal and detecting an offset value from a reference voltage based on a detection result of the continuity detecting means. An optical disc device characterized by the above-mentioned. 6. The optical disk device according to claim 5, wherein the continuity detecting means has at least two or more independent memory areas, and the independent memory area has at least one cycle of a tracking error signal. An optical disc device, which is used as a memory area for storing a waveform and a memory area for performing an operation of a continuity detecting unit. 7. The optical disc device according to claim 5, wherein the continuity detecting means determines and detects continuity of the input tracking error signal every cycle. Optical disk device. 8. An optical disc apparatus provided with a tracking drive means for moving a light spot in a radial direction so that a tracking error signal indicating a positional displacement between a track on an optical disc and a light spot becomes zero, Recording / non-recording discriminating means for discriminating whether a signal is for a recording area or an unrecorded area on an optical disc; and performing the tracking based on a discrimination result of the recording / non-recording discriminating means. An optical disc device, comprising: an offset value detection unit configured to detect an offset value from a reference voltage by integrating an error signal. 9. The optical disc device according to claim 8, wherein the offset value detecting means integrates a tracking error signal in a recording area of the optical disc to detect an offset value from a reference voltage, and a recording area offset value detecting means. An unrecorded area offset value detecting means for integrating a tracking error signal in an unrecorded area of the optical disc to detect an offset value from a reference voltage, wherein the recorded / unrecorded discriminating means comprises an input tracking error signal. Is a tracking error signal in the recording area of the optical disk, the tracking error signal is output to the recording area offset value detection means,
If the input tracking error signal is a tracking error signal in an unrecorded area of the optical disc, the tracking error signal is output to the unrecorded area offset value detecting means. 10. The optical disc device according to claim 8, wherein said recording / non-recording discriminating means discriminates between a recording area and an unrecorded area based on presence / absence of an RF envelope signal or a level difference of a reflected light amount. An optical disc device, characterized by: