JP2927315B2 - Rotary servo circuit of optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk drive.
More specifically, the optical servo circuit
When recording or reproducing data to or from an optical head,
Drive mode so that the disk linear velocity (CLV) is constant.
The present invention relates to a rotation servo circuit of an optical disk device that controls the rotation speed of a motor (spindle motor) .

[0002]

Conventionally, the rotation servo circuit of this kind of optical disc apparatus, for example, as shown in FIG. 3, ATIP signal included in the tracking error signal (TES signal) (absolute time-in pregroo
ve: a wobble signal) and a band-pass filter (BPF) unit 1 of a predetermined band, and an AT passing through the filter unit 1.
A frequency divider 2 for dividing an IP signal by a predetermined ratio, an oscillator 3 for oscillating a clock of a constant frequency, and a frequency divider 4 for dividing the oscillation clock to a clock of a predetermined frequency required for the rotary servo control. A phase comparator 5 for comparing the phase difference between the signals divided by the frequency dividers 2 and 4, and a CLV motor for controlling a drive motor (spindle motor) 7 of the optical disk 6 based on the phase comparison result Servo circuit 8
And

In FIG. 3 , reference numeral 9 denotes an optical head (optical pickup) which irradiates the optical disk 6 with a laser beam and receives and detects the reflected light from the optical disk 6.
Reference numeral 10 denotes a tracking error signal generation unit that generates a tracking error signal (TES signal) based on the detection signal output from the optical head unit 9, and 11 controls the movement of the optical head unit 9 based on the tracking error signal. It is a tracking servo circuit.

[0004] According to this rotation servo circuit, the driving motor 7 based on the bets Rakkin <br/> clock synchronized in phase with ATIP signal included in Guera signals that are controlled, FIG.
As shown in FIG. 4, the center frequency of the ATIP signal is almost 2
From Rukoto is set to 2.05kHz, 22.05kHz ± α passband of filter section 1 accordingly
(3 kHz).

That is, as shown in FIGS. 5 and 6 ,
The optical disc 6, a spiral 6a shape ATIP signal (Wo
Enable signal) 6b is carved, when the optical disk 6 is of a predetermined linear velocity (about 1.4 m / s), the period T of the ATIP signal is such that a 1 / (22.05 kHz)
I have .

[0006]

[SUMMARY OF THE INVENTION Incidentally, frequency of the ATIP signal included in the preparative Rakkin <br/> Guera signal 2
It becomes 2.05 kHz when the linear velocity of the disk 6 with respect to the optical head 9 becomes a regular value (regular rotation speed).

Therefore,,lightThe head 9 is an optical disk 6
Moves greatly from the inner circumference to the outer circumference,ThatFor the optical head 9
ILightDisk 6LineSpeed is half of 1.4m / s
0.7m / sTattoThen, as shown in FIG.,
GOf the ATIP signal included in the racking error signal
The center frequency is almost 11.25 kHz.Therefore, 2
2.05kHz ± 3kHz band filter unit 1
Without tasteATIP signalYou will not get it.

[0008] In this case, until the rotational speed of the optical disk 6 is the vicinity of the normal value, to enter the pass band of the ATIP signal gaff filter unit 1 contained in the knob lithograph tracking error signal, the optical if coarsely adjust the rotation of the disk 6 in any way, the rotation of the optical disk 6 can not be phase locked to the a TIP signal, therefore it is impossible to form a phase locked by the ATIP signal.

The present invention has been made to solve such a problem.
By made is in things, the purpose, the tracking error signal
The ATIP signal included in the signal can be obtained at a high S / N ratio regardless of the rotation number of the optical disk, and the rotation of the optical disk device can be synchronized in phase with the ATIP signal. It is to provide a servo circuit.

[0010]

In order to achieve the above object, the present invention provides a method for rotating an optical disk by a drive motor.
Record or reproduce information with an optical head
At this time, a tracking error signal used for tracking servo control of the optical disk is passed through a filter of a predetermined pass band , and the ATI is extracted from the tracking error signal.
Extract the P signal, driving on the basis of the ATIP signal dynamic motor
Line to control the rotational speed, the optical disc against the optical science head
In a servo circuit of an optical disk device in which the speed is kept constant, an ATIP signal is converted from a tracking error signal.
A digital BPF (band pass filter) having a variable frequency pass band for extracting
Generates a clock signal with a frequency corresponding to the output of the phase comparator
Oscillator and clock of the same
Includes a frequency divider that divides the signal by a predetermined division ratio, and performs phase comparison
ATIP signal extracted by digital BPF
The phases of the divided clock signal that passed through the frequency divider are compared, and the
Predetermined frequency output from voltage controlled oscillator according to phase difference
PLL section that supplies a number of clock signals to a digital BPF
ATIP signal extracted by the digital BPF
Clock signal synchronized with the digital BPF
Used as the base clock synchronized in phase to the ATIP signal
It is characterized by being adapted to control the drive movement motor
You.

[0011] The movement of the optical science head, versus the optical head
If the linear velocity of the optical disc is changed, it is also the frequency of the ATIP signal contained in the companion turned by <br/> tracking error signal varies, according to the present invention, by the PLL section
Thus, a clock of a predetermined frequency synchronized with the ATIP signal is output.

Namely, the basic clock of the clock is de Ijitaru BPF obtained by the PLL unit, to
The passband of the digital BPF is made variable, and the ATI
Since it is set to a value corresponding to the frequency of the P signal, a high S /
Can be obtained ATIP signal N ratio, the driving motor of the optical disc can be C LV servo controlled by the this A TIP signal.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described in more detail based on an embodiment.

FIG . 1 shows a first embodiment of the present invention.
According the rotation servo circuit of the optical disk apparatus, a tracking error signal in those optical disc device (TE
A digital BPF ( band-pass filter) unit 12 that allows the passage of an ATIP signal included in the STI signal, and an ATI extracted by the digital BPF unit 12.
And synchronized in phase with the P signal and a PLL circuit 13 for outputting a clock of a predetermined frequency to the de Ijita <br/> Le BPF section 12.

[0015] The P LL circuit 13, phase comparator 13a,
A clock of a predetermined frequency is output according to the output of the in-phase comparator 13a.
Frequency divider 13c for dividing the VCO for generating a click signal (voltage controlled oscillator) section 13b and a clock signal to a predetermined is
The digital BPF is included in the phase comparison unit 13a.
ATIP signal passing through the section 12 and the signal from the frequency divider 13c
The phase difference between the peripheral clock signals is detected. V CO unit 13b
Since the oscillation frequency of is depending on the CR time constant, the
Oscillation frequency of the clock signal is variable in accordance with the phase difference by the phase comparator 13a.

[0016] For example, the movement of the optical science head portion 9,
0 linear velocity of the optical disk 6 from the normal value 1.4 m / s.
Fluctuate 7m / s, in proportion to the linear velocity, ATIP signal included in the preparative Rakkin <br/> Guera signal 22.05
and changes in 11.025kHz from kHz.

In this case , the frequency division ratio of the frequency divider 13c is set to 1/4.
If, in the V CO unit 13b, 4 × 22.05
kHz = 88.2 kHz to 4 × 11.025 kHz =
So that the oscillation frequency varies in the range of 44.1 kHz, the CR time constant is variable in accordance with the phase difference by the phase comparator 13a.

[0018] Therefore, by a change in the linear velocity as described above, it is included in the tracking error signal ATIP
Also the frequency of the signal changes, the oscillation frequency of the V CO unit 13b according to the phase comparison result by position-phase comparison unit 13a is variable, the clock signal of the variable oscillation frequency A
It is output in phase synchronization with the TIP signal.

[0019] Then, output from the VCO unit 13b
Since the clock signal is a reference clock of de Ijitaru BPF section 12 that, ATI passband of the digital BPF 12 is included in the current tracking error signal
This is the frequency band of the P signal.

[0020] For example, the linear velocity of the optical disc 6 is 1.4m
/ S to 0.7 m / s, the frequency of the ATIP signal included in the current tracking error signal is 2
It changes from 2.05 kHz to 11.25 kHz. At this time, it is sometimes the linear velocity 1.4 m / s V CO unit 13b
22.05 of the oscillation frequency is 88.2kHz, the 1/4 clock of the oscillation frequency by the frequency divider 13c
kHz and this 22.05 kHz clock and A T
The phase difference between the IP signal is obtained by the phase comparator 13 a, the oscillation frequency of the V CO portion 13b in response to the phase comparison result is controlled.

[0021] The change of the linear velocity, the frequency of the ATIP signal contained in the tracking error signal 22.
When the frequency fluctuates from 05 kHz to 11.25 kHz, the oscillation frequency of the VCO unit 13 b is changed to 88.2 k in accordance with the fluctuation.
Hz to 44 . Variable to 1kH z. Since the the variable frequency of the basic clock of the clock is de I di Tal BPF unit 12, so that the pass band of the same di-di Tal BPF unit 12 moves I accompanied Do to variations in the frequency of the ATIP signal .

[0022] Thus, regardless of the rotational speed of the optical disk 6 (irrespective of the variation of the line speed during the rotation of the optical disc 6), AT contained in the tracking error signal
From passing through the I P signal is de Ijitaru BPF unit 12, it is possible to perform conventional similar servo control based on the ATI P signal this was passed.

[0023] That is, the and the ATI P signal and signals the output clock of the oscillating unit 3 obtained by dividing obtained by de Ijitaru BPF unit 12 phase comparison by the phase comparator 5, the phase results in the CLV motor servo circuit 8 Because it is added.

[0024] Thus, creating a clock synchronized in phase with ATIP signal passed through the de-Ijitaru BPF section 12, since as to vary the passband of the digital BPF section 12 by the clock, the movement of the optical head 9 Changes the rotation speed of the optical disk 6, for example, the linear velocity during rotation changes from the normal value of 1.4 m / s to 0.7 m / s.
Be varied to, since the passband of de Ijitaru BPF section 12 is varied accompanied Tsu name to this change, irrespective of the rotational speed of the optical disc 6, regardless of variations in other words line speed, de Ijita < br /> can the ATIP signal included in the tracking error signal by the Le BPF unit 12 to obtain a high S / N ratio,
The drive motor 7 of the optical disk 6 can be controlled by the obtained ATIP signal.

FIG. 2 is a schematic block diagram of a rotary servo control circuit showing a second embodiment of the present invention. In the figure,
The same parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 2 , the rotation servo control circuit of the optical disk device according to the second embodiment is the same as that of the first embodiment.
As a first PLL circuit, in addition to the above,
A rotation speed detector (tach generator) 14 for detecting the rotation speed of the drive motor 7 of the optical disk 6, and outputting a clock of a predetermined frequency in phase synchronization with a detection signal from the rotation speed detector 14; A second PLL circuit 15 that outputs a clock of a predetermined frequency when the operation is stopped ,
Clock output from PLL circuit 13 and second PLL
A switch 16 for switching between the clock output from the circuit 15 and outputting the clock to the digital BPF unit 12 is further provided.

The second PLL circuit 15 includes a phase comparator 15
a, is composed of a VCO portion 15b and divider unit 15c and the like, since the oscillation frequency of the VCO portion 15b is by the CR time constant, the oscillation frequency in accordance with the phase difference by the phase comparator 1 5 a It is the variable.

[0028] In the second embodiment, to rotate the optical disc 6 from the rest, up to a tracking error signal by at least as the optical disk 6 is obtained (until the start), the di-di barrel using a second PLL circuit 15 BPF unit 1
The second pass band is secured. In other words, the
In the first PLL circuit 13 shown in 1 embodiment, although by varying the oscillation frequency by the CR time constant, it is impossible to change the lock at rest state of the optical disc <br/> 6.

By the way, when the driving dynamic motor 7 is stopped, not output rotational speed detection signal from the motor co-generator 14. Therefore , the voltage of the second PLL circuit 15
The CO unit 15b initially generates a clock of a predetermined frequency to set the pass band of the digital BPF unit 12 to a predetermined value,
Thereafter the second PLL circuit 15 outputs a clock of a predetermined frequency phase-locked to the rotation speed detecting signal from the tacho generator 14 I Do with the rotation of the drive motion motor 7.

Further, the predetermined position of the optical disc 6 (e.g. r
= When in 25 mm) of the linear velocity of 1.4 m / s, motor co-generator 14 and outputs the rotational speed detection signal, for example 60 Hz, the frequency divider 15 of the second PLL circuit 15 was or
The frequency division ratio of c is 1/1470, and the oscillation frequency of the VCO unit 15b is 88.2 kHz.

[0031] Then, at the time of startup of the optical disk apparatus, the rotational speed detection signal from the motor co-generator 14 0
From 60 Hz to 60 Hz under the above conditions (r = 25 mm, linear velocity 1.4 m / s).

In this case , the VCO of the second PLL circuit 15
Part 15b already since oscillating at a CR time constant as described, 0 by the rotation speed detection signal and the division ratio 1/1470 of 60Hz from Hz and divided clock are compared at positions phase comparison unit 15a, The VCO unit 15 according to the phase difference
b is oscillation controlled.

[0033] Therefore, and from the second PLL unit 15 outputs a clock phase-synchronized in time <br/> rotation number detection signal, yet it SWITCHING unit 16 at the time of the startup is switched to the terminal 16a side, Further, since the output clock is proportional to the frequency (0 Hz to 60 Hz) of the same rotation speed detection signal, the pass band of the digital BPF section 12 is varied by the proportional predetermined frequency clock.

[0034] Thus, in the startup of the optical disc apparatus, according to the rotation speed of the optical disk 6, i.e. according to the linear velocity of the optical disc 6, the frequency of the ATIP signal contained in the tracking error signal varies, the pass band of de Ijitaru BPF unit 12 also changes by the digital BPF unit 12 can obtain the ATIP signal.

Further, similarly to the conventional case, the above-obtained ATIP
The phase of the signal and the signal obtained by dividing the output clock of the oscillating unit 3 are compared with each other by a phase comparing unit 5.
To be added to the motor servo circuit 8, drive dynamic motor 7 is servo-controlled.

[0036] This servo-control, speed normalization value of driving dynamic motor 7, when the linear velocity of the rotating wife Rihikari disc 6 is substantially 1.4 m / s, the normal operation of the optical disk apparatus, that is recorded , for playback operation, sWITCHING 16
Is switched to the terminal 16b side.

By the switching of the switching unit 16, the first
As described in the embodiment, the pass band of the de Ijitaru BPF section 12 is determined by the output clock from the first PLL unit 13.

As described above, at the time of starting the optical disc apparatus, the lock is applied by the second PLL unit 15,
At times other than at the time of activation, the lock can be applied by the first PLL unit 13.

The first and second PLL units 13, 1
5 locks applied by ATIP signal contained in the tracking error signal, the pass band of de Ijitaru BPF section 12 the first and second PLL unit 13, 15
From being determined to the clock, it is possible to obtain a A TIP signal, the driving motor 7 of the optical disc 6 by the resultant ATIP signal can be CLV control.

[0040]

As described above, according to the present invention ,
Keep the linear velocity of an optical disc in constant with respect to the optical science head
In controlling the urchin drive motor, digital BP the ATIP signal included in the tracking error signal
Removed by F (filter) unit, and the ATI
With a clock of a predetermined frequency phase-locked obtained by the PLL section in the P signal, and the resulting clock and the basic clock de I di <br/> Tal BPF section, the digital BPF
Variable according to the pass band parts to the frequency of the A TIP signal
By the way, Kakawaruko the rotational speed of the optical disc
And without tracking error signal to the de Ijitaru BPF unit
The can be obtained reliably ATIP signal through, the but
It can be faithfully CLV servo controls the drive motor of the optical disc by the ATIP signal obtained with Tteko.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a rotary servo circuit of an optical disk device showing one embodiment of the present invention.

FIG. 2 is a schematic block diagram of a rotary servo circuit of an optical disk device showing another embodiment of the present invention.

FIG. 3 is a schematic block diagram of a rotary servo circuit of a conventional optical disk device.

FIG. 4 is a diagram illustrating a tracking error signal and an ATIP signal in the optical disc device.

FIG. 5 is a schematic front view of the optical disc.

FIG. 6 is a schematic partial enlarged view of an optical disc.

FIG. 7 is a diagram illustrating bands of a tracking error signal, an ATIP signal, and a filter (BPF) in the optical disc device.

[Explanation of symbols]

2, 4, 13c, 15c Frequency divider 3 Oscillator 5, 13a, 15a Phase comparator 6 Optical disk 7 Drive motor (of optical disk 6) 8 CLV motor servo circuit 9 Optical head 10 Tracking error signal generator 12 Digital BPF Reference Signs List 13 first PLL unit 13b, 15b VCO unit 14 rotation speed detector (tach generator) 15 second PLL unit 16 switching unit

Claims (1)

(57) [Claims] An optical disk is rotated by a drive motor.
Record or reproduce information with an optical head
At this time, a tracking error signal used for tracking servo control of the optical disk is passed through a filter having a predetermined pass band , and A
Extract the TIP signal to control the rotational speed of the drive <br/> movement motor based on the ATIP signal, on which pairs to the optical head
In the servo circuit of the optical disc <br/> click device to keep the linear velocity of the serial optical disc constant, the ATIP signal from the upper Symbol tracking error signal extraction
A digital BPF having a variable frequency pass band for output, a phase comparator, and a frequency clock corresponding to the output of the in-phase comparator.
Voltage-controlled oscillator for generating a clock signal and the voltage-controlled oscillator
Frequency divider that divides the clock signal of the oscillator by a predetermined frequency division ratio.
Included, extracted by the digital BPF in the phase comparison section
Divided ATIP signal and the frequency-divided clock that passed through the frequency divider.
Are compared with each other, and according to the phase difference,
The clock having a predetermined frequency output from the pressure-controlled oscillator
And a PLL section for supplying a signal to the digital BPF.
For example, the ATIP signal extracted by the digital BPF
The above clock signal synchronized with the digital BPF itself
Basic used as a clock, the rotation servo circuit of the optical disc apparatus being characterized in that so as to control the upper Symbol driving motor in phase synchronization with the ATIP signal.