JP2000173195A - Optical disk driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the time between a completion of a seek and a start of a data read without disturbing read clock signals during the seek by controlling the frequency of the read clock signals so that the frequency becomes the expected one at a seek destination. SOLUTION: A comparator 220 compares the output of a number of revolution compensator 218 and the period of CK signals being frequency divided and controls a variable oscillator 204 through a switch 211 so that the frequency of the CK signals becomes the data reproducing frequency at a seek destination. When the movement of a unit head is completed, a controller turns on a switch to turn on a tracking control, the switch 211 is switched so that the output of a comparator 210 and the output of a phase comparator 202 pass an address section. Even though the response of a disk motor is slow, the frequency of the CK signals is controlled to be close to a data reproducing frequency at the movement completion point of the head unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk drive for reading information from a disk by converging and irradiating a light beam on the disk, and more particularly to generating a read clock signal as a reference when reading data. It is.

[0002]

2. Description of the Related Art As one of recording media, an optical disk on which video information, computer data, and the like are recorded is widely used. In recent years, there has been a demand for faster data reading and faster seek of an optical disk drive.

In an optical disk drive, in a tracking-on state when reproducing a read-only disk such as a CD medium or a DVD-ROM medium, a read clock signal is controlled so as to be phase-synchronized with an RF signal based on light reflected from the disk. Is done. Conventionally, during a seek operation in which the tracking control is turned off and the head unit is moved to the inner or outer circumference side of the disk, the frequency of the read clock signal is kept at a fixed ratio to the frequency of the specific pattern included in the RF signal. It was controlled to become.

[0004]

Conventionally, when a seek speed is high, the detection operation of a specific pattern is disturbed,
Since the response of the disk motor is delayed, the frequency of the read clock signal greatly deviates from the desired frequency, so that it is not possible to shift to the phase synchronization control immediately after the end of the seek, and the start of the data read is delayed. Was.

[0005] DVD-RAM media and DVD-
When playing recordable discs such as R media,
Since the data is not always present on the track, the RF signal cannot be used, and the frequency of the read clock signal during the period when the light beam irradiates the data unrecorded portion is not fixed.

An object of the present invention is to enable data reading to be started within a short time as possible after the end of seek of an optical disk.

Another object of the present invention is to make it possible to determine the frequency of a read clock signal even when there is a data unrecorded portion on a recordable disc.

[0008]

A first optical disk drive according to the present invention is a device for reading information from a disk by converging and irradiating a light beam on the disk, and for rotating the disk. Means, means for converting reflected light from the disk into an electric signal, clock generating means for generating a variable frequency read clock signal, and so that the read clock signal is phase-synchronized with the electric signal. Phase synchronization control means for controlling the clock generation means, means for moving the light beam toward a target track in the disk, and a frequency of the read clock signal expected at the target track. Frequency control means for controlling the clock generation means such that the movement of the light beam is completed. Immediately before that, the phase synchronization control means to inoperative, and is obtained by adopting a configuration in which a switching means for said frequency control means in an operating state.

A second optical disk drive according to the present invention comprises a plurality of data portions each having a recordable and meandering track, and a plurality of address portions located between adjacent data portions and having addresses previously recorded. A device for reading information by converging and irradiating a light beam on a disk having: a means for rotating the disk; and a means for converting reflected light from the disk to an electric signal. Means for detecting a frequency of a meandering component corresponding to the shape of a track in each of the data portions from the electric signal, clock generating means for generating a read clock signal of a variable frequency, and the read clock signal A phase synchronization control unit for controlling the clock generation unit so as to be phase-synchronized with a signal, and a frequency of the read clock signal, Frequency control means for controlling the clock generation means so as to have a constant ratio with the frequency of the emitted meandering component, and the phase synchronization control means during a period in which the light beam is irradiating each address portion. And a switching unit for setting the frequency control unit to an operating state during a period in which the light beam is irradiating each data unit.

[0010]

Embodiments of the present invention will be described below.

FIGS. 1A, 1B and 1C show a recordable optical disk. The disk 10 is shown in FIG.
As shown in (a), the information area is concentrically divided into a plurality of zones 11, and in each zone 11, the recording linear density becomes lower toward the outer track, and the innermost track of the inner track of each zone 11 is reduced. Information is recorded such that the recording linear density becomes substantially constant. Each zone 11 is shown in FIG.
As shown in (b), it is divided into a plurality of sectors (data portions) 12. Specifically, as shown in an enlarged manner in FIG. 1C, the disk 10 has a plurality of data sections 12 each having recordable and wobble tracks 14 and 15, and a position between adjacent data sections. And a plurality of address portions 13 in which addresses are recorded in advance. Reference numeral 14 denotes a land track of a convex portion, and 15 denotes a groove track of a concave portion. The wobble pitch is set such that the cycle of the wobble signal component in the tracking error signal is about several hundred times the cycle of the read clock signal. The address section 13 is arranged so as to be shifted by a half track in the disk radial direction so that the address section 13 can be read by both the land track 14 and the groove track 15.

FIG. 2 shows an example of the configuration of an optical disk drive according to the present invention. Optical disk drive 10 of FIG.
0 indicates not only a read-only disc (not shown) on which information is recorded so that the recording linear density is substantially constant over the entire recording area, but also a structure as shown in FIGS. 1 (a), 1 (b) and 1 (c). Is configured to be able to reproduce even the recordable disc 10 having the above. The whole operation is controlled by the controller 150. In FIG. 2, a light beam emitted from a light source 101 such as a semiconductor laser is collimated by a collimator lens 102 and then reflected by a polarization beam splitter 103.
The light passes through the 波長 wavelength plate 104, is converged by the converging lens 105, and is irradiated onto the disk 10 rotated by the disk motor 111. The reflected light from the disk 10 passes through a converging lens 105, a quarter-wave plate 104, a polarizing beam splitter 103, and a condenser lens 108, and then irradiates a photodetector 109 for converting this into an electric signal. . The converging lens 105 is an actuator 106
Of the actuator 1
When a current is applied to the focusing coil No. 06, the converging lens 1
05 moves in a direction perpendicular to the information recording surface of the disk 10, and when a current flows through the tracking coil of the actuator 106, the converging lens 105 moves in the radial direction of the disk 10. The head unit 110 includes an actuator 106 and a 波長 wavelength plate 10.
4. Polarizing beam splitter 103, collimator lens 1
02, light source 101, condenser lens 108 and photodetector 10
9 is attached. A slider 113 for moving the head unit 110 toward a target track during a seek operation is provided by the controller 150 by the drive circuit 12.
5 is driven. The rotation speed N of the disk motor 111 is notified to the controller 150, and a CLV (constant
linear velocity) playback, CAV (constant angular v
The rotation speed of the disk motor 111 is controlled via the drive circuit 112 according to the type of playback.

The output of the photodetector 109 consisting of four signals (a to d) passes through an amplifier 114 and is then input to a focus error (FE) circuit 115. This FE circuit 115
Outputs an FE signal indicating the displacement between the focus of the light beam and the information recording surface from the output of the amplifier 114. The FE signal is applied to a focusing coil of the actuator 106 via a phase compensator 117 for compensating the phase and a drive circuit 119 for amplifying the power, and the convergence point of the light beam is adjusted to the information recording surface of the disk 10. Control to be located above.

The output of the photodetector 109 is an amplifier 11
4, a tracking error (TE) circuit 120
Is input to The TE circuit 120 outputs a TE signal indicating a displacement between the focus of the light beam and the track. A phase compensator 122 for compensating the phase of the TE signal is used.
In addition to the tracking coil of the actuator 106 via the switch 123 for turning on and off the tracking control by the controller 150 and the drive circuit 124 for power amplification, the focal point of the light beam is positioned on the track. The convergent lens 105 is controlled.

The output of the photodetector 109 is an amplifier 11
4. After passing through the adder 126, the signal is input to an equalizer (EQ) circuit 130 for amplifying a designated frequency band. This EQ circuit 130 has an RF signal which is an information reproduction signal.
The signal is applied to a PLL (phase-locked loop) circuit 160. The PLL circuit 160 receives various control (CL) signals from the controller 150 and outputs a data (DT) signal and a read clock (CK) signal to a data demodulation circuit (not shown).

The optical disk drive 100 of FIG. 2 uses a wobble circuit 140 for reproducing the recordable disk 10.
And a window comparator 141.
The wobble circuit 140 detects the track 1 from the TE signal.
A wobble (WL) signal is generated according to the shapes of 4 and 15. This WL signal is applied to PLL circuit 160.
The window comparator 141 detects an address (A) indicating the irradiation timing of the address unit 13 from the TE signal.
D) Generate a signal. This AD signal is provided to the controller 150 together with the CK signal.

FIG. 3 shows the PL in FIG. 2 in the case of CLV reproduction.
3 shows a configuration example of an L circuit 160. PLL circuit 160
Is binarized by the binarization circuit 201 and output as a DT signal. When reading data with the tracking control turned on, the phase comparator 202 compares the phase of the DT signal with the CK signal. The phase comparator 202 outputs a signal according to the phase difference between the two signals. This signal is supplied to a switch 211 that is switched according to a switch (SW) signal given from the controller 150.
The phase is corrected by the phase corrector 203 through the filter and input to the variable oscillator 204. The variable oscillator 204 changes the oscillation frequency according to the input signal and outputs an oscillation signal.
This oscillation signal is controlled so as to be phase-synchronized with the DT signal, and is output as a CK signal.

When reproducing a read-only disc (not shown),
When the tracking control is turned off or data cannot be read, the controller 150
11 is switched so that the frequency of the CK signal is controlled to have a fixed ratio with the frequency of the specific pattern included in the RF signal. When the period of the CK signal is T, in the case of a CD medium, the longest pattern included in the RF signal is 11T.
Control is performed so that the frequency of the signal and the frequency of the CK signal are 11: 1. In the case of DVD-ROM media, control is performed so that the frequency of the 14T signal, which is the longest pattern included in the RF signal, and the frequency of the CK signal are 14: 1. In this case, the specific pattern detector 2 is obtained from the DT signal.
07, a specific pattern is detected, and the pattern length is counted by a pulse signal of a fixed frequency clock signal by a pulse width counter 208. The count value is amplified by an amplifier 209 and switched according to a SW signal.
And input to the comparator 210. After the frequency of the CK signal is divided by the frequency divider 205, the cycle is counted by the pulse width counter 206. The count length of the frequency-divided CK signal and the amplified specific pattern length are input to a comparator 210, which outputs a control signal. This control signal is supplied to the switch 211 and the phase corrector 203.
And is input to the variable oscillator 204. In this way, the frequency of the CK signal is controlled so as to have a constant ratio to the frequency of the specific pattern.

When the tracking control is off, an RF signal is not correctly output between tracks. In this case, when a specific pattern is detected from the DT signal, a portion where there is no RF signal is detected, and the specific pattern detector 207 malfunctions to lower the frequency of the CK signal below a desired frequency. For this reason, the RF signal is compared with a threshold level (TH) signal by the comparator 212, and the comparator 2
12 holds (H) if the amplitude of the RF signal is less than a certain value.
D) Output a signal. A specific pattern detector 207 and a pulse width counter 208 are used between tracks by this HD signal.
Suspends operation and prevents disruption between tracks.

When reproducing the read-only disk, the controller 150 switches the switch 123 to turn on the tracking control, and then the frequency of the specific pattern in the RF signal and the frequency of the CK signal have a substantially constant ratio. Then, the switch 211 is switched to switch to the phase synchronization control of the DT signal and the CK signal.

When reproducing the recordable disc 10,
The cycle of the WL signal is counted by the pulse width counter 215, the count value is amplified by the amplifier 216, and input to the comparator 210 through the switch 214 switched by the controller 150. Comparator 210 outputs a control signal such that the period of the CK signal becomes a constant ratio with respect to the period of the WL signal. This control signal is transmitted to the switch 21
1. The signal is input to the variable oscillator 204 through the phase corrector 203. As a result, the frequency control is performed so that the frequency of the CK signal becomes a constant ratio with respect to the frequency of the WL signal.

The PLL circuit 160 shown in FIG. 3 includes a rotational speed corrector 218 and a comparator 2 for a seek operation during CLV reproduction.
20 is further provided. The rotation speed corrector 218 converts the target period TF (or target frequency) of the CK signal for realizing a predetermined data reproduction frequency, the current rotation speed N of the disk motor 111, and the target rotation speed N2 into the controller 1.
50, and outputs a corrected target value obtained by multiplying a target period TF (or a target frequency) by a ratio N / N2 of the target rotation speed N2 and the current rotation speed N. The comparator 220 compares the output of the rotation speed corrector 218 with the cycle of the frequency-divided CK signal, and controls the variable oscillator 204 through the switch 211 so that the frequency of the CK signal becomes the data reproduction frequency of the seek destination.
Control.

FIGS. 4A, 4B and 4C are explanatory diagrams of the wobble circuit 140 in FIG. Wobble circuit 1
4 includes a band-pass filter (BPF) 140a and a binarization circuit 140b, as shown in FIG. The BPF 140a generates a wobble detection (WD) signal from the TE signal. This WD signal is converted into a WL signal by the binarization circuit 140b. FIG. 4B shows the waveform of the WD signal, and FIG. 4C shows the waveform of the WL signal. T12 in the figure indicates that the light beam is the data part 1
2, and T13 represents an address period in which a light beam irradiates the address unit 13, respectively. The WD signal in the data period T12 is TE
These are frequency components corresponding to the wobble pitch of the tracks 14 and 15 extracted from the signal. FIG. 4C shows a frequency change of the WL signal.

FIGS. 5A, 5B and 5C are diagrams for explaining the operation of the optical disk drive 100 of FIG. 2 when reproducing the recordable disk 10. FIG. FIG. 5 (a) and (b)
Indicates the operation of the window comparator 141.
Since the address section 13 is shifted by half a track from the data section 12, the address section T13 is compared with the data section T12.
, The amplitude of the TE signal increases. The window comparator 141 generates a pulse of the AD signal when the level of the TE signal is higher than the upper threshold level (UTH) or when the level of the TE signal is lower than the lower threshold level (LTH). Controller 150
Is the AD given by the window comparator 141.
The data section 12 and the address section 13 can be identified by the signal. FIG. 5C shows the SW signal given from the controller 150 to the switches 211 and 214. That is, the frequency of the CK signal is determined by the frequency control by the comparator 210 using the WL signal in the data period T12, and the phase synchronization control of the DT signal and the CK signal by the phase comparator 202 is selected in the address period T13. Therefore, even when the data section 12 is in an unrecorded state, the frequency of the CK signal does not shift since control is performed based on the WL signal. Further, since the address section 13 switches to the phase synchronization control, the address can be read stably. When reading the data recorded in the data section 12, the controller 150
1 is switched to the phase synchronization control. As a result, the CK signal is controlled so that the phase is synchronized with the DT signal reflecting the read data.

Although the CK signal may be phase-synchronized with the WL signal, once the synchronization is lost, it takes time to recover, so that the above-described frequency control is more advantageous. The pulse width counter 215, the amplifier 216, etc. are replaced with a pulse width counter 208 for detecting a specific pattern, an amplifier 209.
Etc. can be shared. In this way, the circuit scale can be reduced, and the conventional magneto-optical disk (MO)
This is advantageous in terms of circuit size and cost as compared with using a reference clock generation synthesizer used in a drive or the like.

Next, the seek of the recordable disc 10 will be described with reference to FIGS. 6, 7A, 7B and 7C. FIG. 6 shows the rotation speed N of the disk motor 111 with respect to the reproduction position at the time of CLV reproduction of the recordable disk 10. FIGS. 7 (a), (b) and (c)
FIG. 5 is an explanatory diagram of the operation of the PLL circuit 160 in FIG. 3 before and after a seek of the recordable disc 10.

The switch 214 is switched so that the output of the amplifier 216 passes. The switch 211 controls the frequency control using the WL signal in the data unit 12 and the address unit 1.
In step 3, phase synchronization control using the DT signal is selected. In this state, the controller 150 turns off the switch 123, sends a signal to the drive circuit 125, drives the slider 113, and moves the head unit 110 to the target track position. When the switch 123 is turned off, the head unit 11
While moving 0, the controller 150 switches the switch 211 so that the output of the comparator 220 passes.

At the time of CLV reproduction of the recordable disk 10, as shown in FIG. 6, a ZCLV for changing the rotation speed N of the disk motor 111 according to the zone 11 at the reproduction position.
Control is executed. However, for example, when the head unit 110 is moved from the position X1 (the rotation speed N1) to the position X2 at a high speed, if the response of the disk motor 111 is slow, the actual rotation speed N differs from the target rotation speed N2. In this case, since the linear velocity is different from the specified velocity, the data reproduction frequency is also different from the predetermined reproduction frequency. On the other hand, as described above, the rotation speed corrector 218 outputs the target period TF of the CK signal for realizing the predetermined data reproduction frequency.
And the current rotation speed N of the disk motor 111 and the target rotation speed N2 from the controller 150, and calculates the ratio N / N2 of the target rotation speed N2 and the current rotation speed N to the target cycle T
The correction target value multiplied by F is output. The comparator 220 compares the output of the rotation speed corrector 218 with the period of the frequency-divided CK signal, and controls the variable oscillator 204 through the switch 211 so that the frequency of the CK signal becomes the data reproduction frequency of the seek destination. Control. Then, as shown in FIGS. 7A, 7B and 7C, at time t1 when the movement of the head unit 110 is completed, the controller 150
To turn on the tracking control and switch 211
Is switched so that the output of the comparator 210 passes through the data section 12 and the output of the phase comparator 202 passes through the address section 13.

As described above, according to the present invention, even if the response of the disk motor 111 is slow, the head unit 110
Since the frequency of the CK signal has already been controlled near the data reproduction frequency at the end of the movement, the address can be read immediately after the end of the seek, and the time until the start of the data read can be shortened.

Next, FIGS. 8, 9 (a), (b), (c)
The seek of the read-only disc will be described with reference to FIGS. FIG. 8 shows the rotation speed N of the disk motor 111 with respect to the reproduction position at the time of CLV reproduction of the reproduction-only disk. FIGS. 9A, 9B, 9C, and 9D show FIGS. 3A and 3B before and after the seek of the read-only disc.
3 is an operation explanatory diagram of the PLL circuit 160 of FIG.

The switch 214 is switched so that the output of the amplifier 209 passes. The switch 211 is switched so that the output of the phase comparator 202 passes therethrough.
The phase synchronization control between the K signal and the DT signal is executed.
In this state, the controller 150 turns off the switch 123, sends a signal to the drive circuit 125, drives the slider 113, and moves the head unit 110 to the target track position. While the switch 123 is turned off and the head unit 110 is moving, the controller 150 switches the switch 211 so that the output of the comparator 220 passes.
As shown in FIG. 9B, when the track traversing speed increases during the seek, the HD signal is not output.

At the time of CLV reproduction of a reproduction-only disk, as shown in FIG.
The number of rotations N of 1 is continuously changed. However, for example, when the head unit 110 is moved at a high speed from the position X1 (the rotation speed N1) to the position X2, the disk motor 11
If the response 1 is slow, the actual rotation speed N differs from the target rotation speed N2. In this case, since the linear velocity is different from the specified velocity, the data reproduction frequency is also different from the predetermined reproduction frequency. On the other hand, as described above, the rotation speed corrector 218 calculates the target period TF of the CK signal for realizing the predetermined data reproduction frequency, the current rotation speed N of the disk motor 111, and the target rotation speed N2. Ratio N / N of target rotational speed N2 received from controller 150 and current rotational speed N
Then, a correction target value obtained by multiplying the target cycle TF by 2 is output. The comparator 220 outputs the output of the rotation speed corrector 218 and the divided C
The variable oscillator 204 is controlled through the switch 211 so that the cycle of the K signal is compared with the cycle of the K signal so that the frequency of the CK signal becomes the data reproduction frequency of the seek destination. And FIG.
As shown in (a), (b), (c) and (d), at time t1 when the movement of the head unit 110 ends, the controller 150 switches the switch 211 so that the output of the comparator 210 passes, and the switch 123 Is turned on to turn on tracking control, and when the frequency of the specific pattern included in the RF signal and the frequency of the CK signal have a fixed ratio, the switch 211 is further switched to control the phase synchronization of the DT signal and the CK signal. Move to

As described above, according to the present invention, even if the response of the disk motor 111 is slow, the head unit 110
Since the frequency of the CK signal has already been controlled to the vicinity of the data reproduction frequency at the end of the movement, it is possible to shift to the phase synchronization control immediately after the end of the seek, and to shorten the time until the start of the data read. .

FIG. 10 shows P in FIG. 2 in the case of CAV reproduction.
4 shows a configuration example of an LL circuit 160. The configuration in FIG. 10 is such that the rotational speed corrector 218 and the comparator 220 in FIG. The comparator 320
It receives a target frequency F2 (or a target cycle) of the CK signal for realizing a predetermined data reproduction frequency, and controls the variable oscillator 204 through the switch 211 so that the frequency of the CK signal becomes the data reproduction frequency of the seek destination.

Here, FIGS. 11, 12 (a) and 12 (b)
The seek of the recordable disc 10 will be described with reference to FIG. FIG. 11 shows the frequency F of the CK signal with respect to the reproduction position at the time of CAV reproduction of the recordable disc 10. The rotation speed of the disk motor 111 is kept substantially constant. FIGS. 12A and 12B show the recordable disc 1.
FIG. 11 is an explanatory diagram of an operation of the PLL circuit 160 in FIG. 10 before and after a seek of 0.

The switch 214 is switched so that the output of the amplifier 216 passes. The switch 211 controls the frequency control using the WL signal in the data section 12 and the address section 1.
In step 3, phase synchronization control using the DT signal is selected. In this state, the controller 150 turns off the switch 123, sends a signal to the drive circuit 125, drives the slider 113, and moves the head unit 110 to the target track position. When the switch 123 is turned off, the head unit 11
While moving 0, the controller 150 switches the switch 211 so that the output of the comparator 320 passes.

At the time of CAV reproduction of the recordable disk 10, as shown in FIG. 11, the frequency F of the CK signal is changed according to the zone 11 at the reproduction position. For example, when the head unit 110 is moved from the position X1 to the position X2, C
The frequency F of the K signal changes from F1 to F2. Therefore, the controller 150 gives the comparator 320 a target frequency F2 (or a target period) of the CK signal that will be the data reproduction frequency in the seek destination zone. Thereby, as shown in FIG. 12B, the frequency of the CK signal is controlled during the seek so as to be near the data reproduction frequency in the seek destination zone. And head unit 1
At the time point t1 when the movement of No. 10 is completed, the controller 150 turns on the switch 123 to turn on the tracking control,
The switch 211 is switched so that the comparator 21
The output of 0 is switched so that the output of the phase comparator 202 passes through the address unit 13.

As described above, according to the present invention, the frequency of the CK signal is already controlled to the vicinity of the data reproduction frequency at the end of the movement of the head unit 110 even if the data reproduction frequency differs depending on the seek destination zone. The address can be read immediately after the seek is completed, and the time until the start of the data read can be shortened.

Next, the seek operation of the read-only disc will be described with reference to FIGS. FIG. 13 shows the frequency F of the CK signal with respect to the reproduction position at the time of CAV reproduction of the reproduction-only disc. The rotation speed of the disk motor 111 is kept substantially constant. FIGS. 14 (a), (b) and (c) show the PLL circuit 160 of FIG.
It is operation | movement explanatory drawing of FIG.

The switch 214 is switched so that the output of the amplifier 209 passes. The switch 211 is switched so that the output of the phase comparator 202 passes therethrough.
The phase synchronization control between the K signal and the DT signal is executed.
In this state, the controller 150 turns off the switch 123, sends a signal to the drive circuit 125, drives the slider 113, and moves the head unit 110 to the target track position. While the switch 123 is turned off and the head unit 110 is moving, the controller 150 switches the switch 211 so that the output of the comparator 320 passes.
As shown in FIG. 14B, when the track traversing speed increases during the seek, the HD signal is not output.

At the time of CAV reproduction of a reproduction-only disc, as shown in FIG. 13, the frequency F of the CK signal is continuously changed according to the reproduction position. For example, from position X1 to position X2
The frequency F of the CK signal changes from F1 to F2. Therefore, the controller 150 gives the comparator 320 a target frequency F2 (or a target period) of the CK signal that becomes the data reproduction frequency in the seek destination track. As a result, FIG.
As shown in (c), the frequency of the CK signal is controlled during the seek so as to be near the data reproduction frequency of the seek destination track. Then, at time t1 when the movement of the head unit 110 is completed, the controller 150 switches the switch 211 so that the output of the comparator 210 passes therethrough, turns on the switch 123, turns on the tracking control, and sets R
When the frequency of the specific pattern included in the F signal and the frequency of the CK signal reach a fixed ratio, the switch 211 is further switched to shift to the phase synchronization control of the DT signal and the CK signal.

As described above, according to the present invention, the frequency of the CK signal is already controlled to the vicinity of the data reproduction frequency at the end of the movement of the head unit 110 even if the data reproduction frequency differs depending on the seek destination track. ,
It is possible to shift to the phase synchronization control immediately after the end of the seek, and it is possible to shorten the time until the start of the data read.

In the example of the CLV reproduction, the correction is performed based on the target rotation speed N2 of the disk motor 111. However, if the rotation speed fluctuates greatly, the rotation speed of the next rotation greatly differs from the current rotation speed. Therefore, even if the correction is performed, the error increases. On the other hand, for example, the next rotation speed is obtained by linear interpolation from the rotation speed Nold one rotation before and the current rotation speed N, and the CK signal of the CK signal is obtained from the obtained next rotation speed and the target rotation speed N2 at the seek destination. When the target cycle is multiplied by (2 × N−Nold) / N2, the correction can be performed with higher accuracy. Especially head unit 1
When the object 10 is moved over a long distance, the fluctuation of the number of rotations is also large, so that the effect of the above processing is large.

Further, in the above-described reproduction example of the reproduction-only disc, the switch 211 is switched so that the output of the comparator 210 passes after the movement of the head unit 110 is completed. If the switch 211 is changed to a speed lower than or equal to the speed, the process can be shifted to the phase synchronization control quickly, so that the time until the start of data reading can be further reduced.

In each of the above examples, the head unit 110
After the end of the movement, the switch 211 is switched so that the output of the comparator 210 passes. However, when the frequency control accuracy and the movement accuracy of the head unit 110 are high, the frequency of the CK signal is almost immediately controlled to the target frequency at an early stage. Therefore, switching may be performed so that the output of the phase comparator 202 passes immediately after the end of the seek. In this case, the phase comparator 20
Since the process shifts to the phase synchronization control using the output of No. 2, the time until the start of data reading can be further reduced.

In the example of FIG. 10, the target frequency (or target period) of the CK signal during the seek is fixed. However, when the fluctuation of the rotation speed of the disk motor 111 or the control residual is large, In the same manner as in the example of FIG. 3, the current rotational speed N of the disk motor 111 and the target rotational speed
By correcting the target frequency (or target cycle) of the K signal, it is possible to control the CK signal with higher accuracy. In this case, a PLL circuit having the same configuration can be used regardless of CLV reproduction or CAV reproduction, so that the circuit can be simplified and the control can be simplified.

[0047]

As described above, the first aspect of the present invention is as follows.
According to the optical disk drive of the above, since the frequency of the read clock signal is controlled so as to be the expected frequency at the seek destination during the seek, the read clock signal is not disturbed during the seek, and after the seek is completed. The time until the start of data reading can be reduced.

According to the second optical disk drive of the present invention, the read clock signal is generated based on the frequency of the meandering signal component corresponding to the meandering shape of the track during the period in which the data beam is not irradiated on the data unrecorded portion. Is controlled, the frequency of the read clock signal during this period can be determined.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are diagrams showing a configuration example of a recordable disc.

FIG. 2 is a block diagram illustrating a configuration example of an optical disk drive according to the present invention.

FIG. 3 is a block diagram illustrating a configuration example of a PLL circuit in FIG. 2;

4 (a), (b) and (c) are explanatory diagrams of the wobble circuit in FIG. 2;

5 (a), (b) and (c) are explanatory diagrams of the operation of the optical disk drive of FIG. 2 when reproducing a recordable disk.

FIG. 6 is a diagram showing a motor rotation speed with respect to a reproduction position at the time of CLV reproduction of a recordable disc.

7 (a), (b) and (c) are explanatory diagrams of the operation of the PLL circuit of FIG. 3 before and after seeking a recordable disc.

FIG. 8 is a diagram showing a motor rotation speed with respect to a reproduction position at the time of CLV reproduction of a reproduction-only disc.

9 (a), (b), (c) and (d) are explanatory diagrams of the operation of the PLL circuit of FIG. 3 before and after seeking a read-only disc.

FIG. 10 is a block diagram showing another configuration example of the PLL circuit in FIG. 2;

FIG. 11 is a diagram illustrating a frequency of a read clock signal with respect to a reproduction position during CAV reproduction of a recordable disc.

FIGS. 12 (a) and (b) are explanatory diagrams of the operation of the PLL circuit of FIG. 10 before and after seeking of a recordable disc.

FIG. 13 is a diagram illustrating the frequency of a read clock signal with respect to a reproduction position during CAV reproduction of a read-only disc.

14 (a), (b) and (c) are explanatory diagrams of the operation of the PLL circuit of FIG. 10 before and after seeking a read-only disc.

[Explanation of symbols]

 Reference Signs List 10 optical disk 11 zone 12 sector (data part) 13 address part 100 optical disk drive 109 photodetector 110 head unit 111 disk motor 113 slider 115 focus error circuit 120 tracking error circuit 140 wobble circuit 141 window comparator 150 controller 160 PLL circuit 202 phase Comparator 204 Variable oscillator 209 Amplifier 210, 220 Comparator 211, 214 Switch 218 Rotation speed compensator 320 Comparator

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Mitsuro Moriya 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Takashi Kishimoto 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (10)

[Claims] 1. An optical disk drive for converging and irradiating a light beam onto a disk to read information from the disk, comprising: means for rotating the disk; and light reflected from the disk converted into an electric signal. Means for converting; clock generating means for generating a variable frequency read clock signal; and phase synchronization control means for controlling the clock generation means so that the read clock signal is phase-synchronized with the electric signal. Means for moving the light beam toward a target track in the disk; and means for controlling the clock generation means such that the frequency of the read clock signal is the frequency expected in the target track. Frequency control means, at least immediately before the movement of the light beam is completed, Optical disk drive, wherein a means is inoperative, and with a switching means for the operation states the frequency control means. 2. The optical disk drive according to claim 1, wherein information is recorded on the disk such that a recording linear density is substantially constant over the entire information area, and the optical disk drive is configured to control the light beam. The apparatus further comprises means for detecting a rotation speed of the disk that is changed according to a position, wherein the frequency control means determines that a frequency of the read clock signal is a rotation speed of the disk detected and a speed of the target track. An optical disk drive, wherein the clock generating means is controlled to have a frequency determined according to a target rotational speed at a position. 3. The optical disk drive according to claim 1, wherein information is recorded on the disk such that a recording linear density is substantially constant over an entire information area, and the optical disk drive rotates the disk. The apparatus further comprises means for keeping the speed substantially constant, wherein the frequency control means controls the clock generation means so that the frequency of the read clock signal becomes a target frequency at the position of the target track. Optical disk drive. 4. The optical disk drive according to claim 1, wherein the information area of the disk is divided concentrically into a plurality of zones, and in each of the zones, the recording linear density becomes lower toward the outer track, and Information is recorded such that the recording linear density of the innermost track of each of the zones is substantially constant, and the optical disc driving device changes the rotation speed of the disc, which is changed according to the position of the light beam. The frequency control means may further include a frequency for determining the frequency of the read clock signal according to a detected rotational speed of the disk and a target rotational speed in a zone to which the target track belongs. An optical disk drive, wherein the clock generating means is controlled so that the clock generating means is controlled. 5. The optical disk drive according to claim 1, wherein the information area of the disk is divided concentrically into a plurality of zones, and in each of the zones, the recording linear density becomes lower as the track on the outer periphery becomes lower, and Information is recorded such that the recording linear density of the innermost track of each zone is substantially constant, and the optical disk drive further includes means for keeping the rotation speed of the disk substantially constant, An optical disk drive, wherein the frequency control means controls the clock generation means so that the frequency of the read clock signal becomes a target frequency in a zone to which the target track belongs. 6. The optical disk drive according to claim 1, wherein the switching means keeps the phase synchronization control means inactive while the light beam is moving, and keeps the frequency control means operating. An optical disk drive characterized by the following. 7. The optical disk drive according to claim 1, wherein the switching unit is configured to: when the movement of the light beam ends,
An optical disk drive, wherein the frequency control means is set to a non-operation state, and the phase synchronization control means is set to an operation state. 8. A light beam is convergently irradiated on a disk having a plurality of data portions each having a recordable and meandering track and a plurality of address portions located between adjacent data portions and having a pre-recorded address. An optical disk drive for reading information by rotating the disk; a means for converting reflected light from the disk into an electric signal; and Means for detecting the frequency of the meandering component according to the shape of the track; clock generating means for generating a read clock signal of a variable frequency; and the clock so that the read clock signal is phase-synchronized with the electric signal. Phase synchronization control means for controlling the generation means, and the frequency of the read clock signal is Frequency control means for controlling the clock generation means so as to have a constant ratio with frequency, and the phase synchronization control means during the period when the light beam is irradiating each address part, An optical disk drive, comprising: switching means for setting each of the frequency control means to an operating state during a period in which the light beam is being irradiated. 9. The optical disk drive according to claim 8, wherein the switching unit causes the frequency control unit to be in an inoperative state during a period in which the light beam is irradiating each of the address units. Optical disk drive. 10. The optical disk drive according to claim 8, wherein, when reading out data recorded in each of the data sections, the switching section performs the operation during a period in which the light beam is irradiating the data sections. An optical disk drive, wherein the frequency control means is set to a non-operation state, and the phase synchronization control means is set to an operation state.