JPH11203687A - Tln signal generation device of optical disk device and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to grasp an accurate position of an optical head to an optical disk at the time of moving the optical head. SOLUTION: The optical disk device is a CD-R drive device for recording/ reproducing an optical disk (CD-R). This optical device amplifies AC components of 1 kHz or higher frequencies included in TLN signal in a state in which offset component (DC component) included in the TNL signal is maintained as it is, by letting the TNL signal generated by the track loss (TNL) signal, generating circuit 75 pass through a high-boost filter 71. The TNL signal having passed through the highfilter 71 is binarized by a binarization circuit 76. This binarized TNL signal is inputted to a CD(compact disk) servo controller, and used in fine searching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a TLN signal generation device and an optical disk device for an optical disk device for reproducing or recording / reproducing an optical disk.

[0002]

2. Description of the Related Art Generally, an optical disk device drives a reproduction-only CD (compact disk) such as a music CD and a CD-ROM, and an optical disk such as a recordable / reproducible CD-R. The optical disk device has an optical head (optical pickup) that can move in the radial direction with respect to a disk-shaped optical disk, and an optical head moving mechanism that includes a thread motor that moves the optical head in the radial direction. .

The optical head includes an optical head body having a laser diode and a split photodiode, and an objective lens supported by the optical head body by a suspension spring so as to be movable in the radial direction and the rotation axis direction of the optical disk. And an actuator for moving the objective lens in the rotation axis direction and the radial direction.

[0004] In such an optical disk device, data recorded spirally on the optical disk is reproduced while rotating the optical disk and moving the optical head in the radial direction so as to follow the track.

When the optical head is moved to a predetermined track on the optical disk, track jump control is performed. For example, when a song number (for example, the third song) is selected, the optical head can be automatically moved to the target track by performing track jump control. Therefore, a desired song is immediately selected and reproduced. Can be.

Usually, the track jump in the optical disk drive includes a rough search and a fine search. Of these, the rough search is used when jumping to a relatively distant track, and the fine search is used for a relatively short track. Used when jumping to a track.

Hereinafter, the operation principle of the fine search will be described. FIG. 27 shows pregrooves (WOBBLE) 101a and 101 formed on the optical disc.
b and lands 102 formed at both ends
It is a figure which shows a, 102b ... typically. Information (data) is recorded in the pre-grooves 101a, 101b,. That is, the pits are
a, 101b...

The laser beams (main beam and sub beam) emitted from the laser diode of the optical head are divided into pre-grooves 101a, 101b,.
, And reflected light 103a to 103c
Are respectively received by the divided photodiodes. Various signals such as a track loss signal (hereinafter, referred to as a TLN signal; details of the TLN signal will be described later) are generated based on the signal from the optical head.

Here, when performing a fine search, the optical head is moved in the radial direction of the optical disk (the direction of the arrow "Y" in FIG. 27), so that the optical head is pre-groove, land, pre-groove.・ In other words, the pre-groove and the land cross alternately. As shown in FIG. 28, the level of the TLN signal S1 at this time rises when the main beam passes through the pregrooves 101a, 101b,.
.. A wave-shaped signal whose level drops when passing through the portion

Therefore, when a track jump is performed in the fine search, the number of peaks of the TLN signal S1 may be counted. That is, as shown in FIG. 28, a certain reference level L1 is set, and the TLN signal S1 is binarized based on the reference level L1, and TL
By counting the number of times that the N signal S1 exceeds the reference level L1, it is possible to jump to a desired track. For example, when a command to move 10 tracks is given, the TLN obtained from the received signal
The optical head may be moved until the signal exceeds the reference level L1 ten times.

However, actually, the TLN signal S1
Has an offset component (DC component), not a waveform having the same amplitude up and down around the reference level L1. Therefore, the TLN signal S1 is equal to the reference level L1.
Vibrates up and down around a level L2 which is shifted by a certain value from. The offset component changes depending on various factors such as ambient temperature, aging, the degree of tilt of the optical pickup, the state of mounting the optical disk, and the like. Therefore, depending on the magnitude of the offset component, the TLN signal S1 may vibrate. , TLN signal S1 may not cross the reference level L1. In this case, the TLN signal S1 cannot be binarized with high accuracy. That is, although the optical head actually crosses the track, this is not counted at the time of the fine search, and there is a possibility that the optical head cannot be moved to the target track.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a TLN signal generating apparatus and an optical disk apparatus for an optical disk apparatus which can accurately grasp the position of the optical head with respect to the optical disk when the optical head moves.

[0013]

This and other objects are achieved by the present invention which is defined below as (1) to (6).

(1) A TLN signal generation circuit for generating a TLN signal (track loss signal) based on a signal from an optical head of an optical disk device, and a DC component included in the TLN signal generated by the TLN signal generation circuit A signal correction circuit for amplifying an AC component included in the TLN signal without removing the TLN signal.

(2) The signal correction circuit includes the TLN
Without removing the direct current component and the alternating current component below the first frequency included in the TLN signal generated by the signal generation circuit, the alternating current above the second frequency higher than the first frequency included in the TLN signal is removed. The TLN signal generation device for an optical disk device according to the above (1), wherein the TLN signal generation device is configured to amplify the component.

(3) The TLN signal generating device for an optical disk device according to the above (1) or (2), wherein the signal correction circuit comprises a high boost filter.

(4) The above-mentioned (1) having a binarization circuit for comparing the level of the TLN signal amplified by the signal correction circuit with a reference level and binarizing the TLN signal.
Or the TL of the optical disc device according to any one of (3) to (3).
N signal generator.

(5) An optical disc device having the TLN signal generating device according to any one of (1) to (4).

(6) An optical head, and an optical head moving mechanism for moving the optical head, wherein the diameter of the optical head relative to the optical disk with respect to the optical disk is based on a TLN signal obtained from the TLN signal generating device. The optical disc device according to the above (5), which is configured to grasp the position in the direction.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a TLN signal generating apparatus for an optical disk apparatus according to the present invention and an optical disk apparatus having the same will be described in detail with reference to the preferred embodiments shown in the accompanying drawings.

FIG. 1 is a block diagram showing a state in which the optical disk device of the present invention is connected to a computer, and FIG. 2 is a block diagram showing an embodiment of the optical disk device of the present invention.

The optical disk device 1 shown in these figures is a CD-R drive device for recording and reproducing an optical disk (CD-R) 2.

A spiral pre-groove (WOBBLE: not shown) is formed on the optical disk 2.

This pre-groove meanders at a predetermined period (22.05 kHz at 1 × speed), and the pre-groove has an ATIP (Absolute Time In Pre-Groove).
) Information (time information) is recorded. In this case, A
The TIP information is bi-phase modulated.
It is FM-modulated and recorded at a carrier frequency of 05 kHz.

The pregroove functions as a guide groove when forming pits / lands on the optical disc 2 (pit / land recording). Also, this pre-groove is played,
It is used for controlling the rotation speed of the optical disc 2 and for specifying the recording position (absolute time) on the optical disc 2.

The optical disk device 1 includes a turntable and a spindle motor 8 for rotating the turntable.
It has a rotation drive mechanism (not shown) for mounting the optical disk 2 on the turntable and rotating it. A Hall element 9 is installed near the spindle motor 8.

The optical disk apparatus 1 has an optical head (optical pickup) 3 that can move in the radial direction of the optical disk 2 (radial direction of the turntable) with respect to the loaded optical disk 2 (turntable), and An optical head main body moving mechanism (not shown) including a sled motor 5 for moving the head 3 in the radial direction, that is, an optical head main body (optical pickup base) of the optical head 3 described later in the radial direction, and drivers 6 and 11 And PWM
Signal smoothing filters 7 and 12, control means 13,
Laser control unit 14, HF signal generation circuit 15, HF signal gain switching circuit 16, peak / bottom detection circuit 17, PU drive control signal generation circuit (optical head drive control signal generation circuit) 18, and WOBBLE signal detection Circuit 1
9, a CD servo controller 21, a WOBBLE servo controller 22, an FG signal binarization circuit 23,
EFM / CDROM encoder control unit 24, memories 25, 26 and 29, sync signal generation / ATIP decoder 27, CDROM decoder control unit 28, interface control unit 31, clocks 32, 33, 34
And 35, and a casing 10 for accommodating them. Hereinafter, the radial direction of the optical disk 2 is simply referred to as “radial direction”.

The optical head 3 includes an optical head body (optical pickup base) (not shown) having a laser diode (light source) and a split photodiode (light receiving element),
An objective lens (condensing lens). The driving of the laser diode is controlled by the laser controller 14.

The objective lens is supported by a suspension spring (not shown) provided on the optical head main body, and can move in the radial direction and the rotation axis direction of the optical disk 2 (turntable) with respect to the optical head main body. ing. When the objective lens deviates from its neutral position (middle point), the objective lens is urged toward the neutral position by the restoring force of the suspension spring. Hereinafter, the direction of the rotation axis of the optical disc 2 will be simply referred to as “the direction of the rotation axis”.

The optical head 3 has an actuator 4 for moving the objective lens in the radial direction and the rotation axis direction with respect to the optical head main body.

The control means 13 is usually constituted by a microcomputer (CPU), and comprises an optical head 3 (actuator 4), a sled motor 5, a spindle motor 8, a laser control unit 14, an HF signal gain switching circuit 16, a peak / bottom Detection circuit 17, CD servo controller 2
1, WOBBLE servo controller 22, EFM / C
DROM encoder control unit 24, memories 25 and 26,
29, sync signal generation / ATIP decoder 27, CDR
OM decoder control unit 28, interface control unit 31
For example, the entire optical disk device 1 is controlled.

The address, data, and COMMAN are sent from the control means 13 via the address / data bus 36.
D (command) and the like are input to the EFM / CDROM encoder control unit 24, the memory 26, the sync signal generation / ATIP decoder 27, the CDROM decoder control unit 28, the interface control unit 31, and the like.

An external device (a computer 41 in this embodiment) is detachably connected to the optical disk device 1 via an interface control section 31 so that communication between the optical disk device 1 and the computer 41 can be performed. it can.

The interface control unit 31 includes, for example, ATAPI (IDE) (Attape standard), SC
SI (squay standard) or the like is used.

The computer 41 has a keyboard 4
2. The mouse 43 and the monitor 44 are connected respectively. Note that a transmission unit is configured by the interface control unit 31.

Further, an HF signal generation circuit 15, an HF signal gain switching circuit 16, a peak / bottom detection circuit 17,
Error signal generation circuit 18, WOBBLE signal detection circuit 1
9. The signal processing means is constituted by the CD servo controller 21 and the WOBBLE servo controller 22.

An optical head moving mechanism is constituted by the optical head main body moving mechanism and the actuator 4.

Next, the operation of the optical disk device 1 will be described. The optical disc device 1 records (writes) and reproduces (reads) information (data) on the optical disc 2 while performing focus control, tracking control, thread control, and rotation speed control (rotation speed control) on a predetermined track. I do. Hereinafter, recording, reproduction, focus control, tracking control and thread control,
The operation at the time of track jump control (movement control of the optical head) and rotation speed control (rotation speed control) will be described.

First, as a premise, as shown in FIG. 2, a predetermined COMMAND signal is input from the control means 13 to the CD servo controller 21. Control means 1
From 3, a predetermined COMMAND signal is input to the WOBBLE servo controller 22.

This COMMAND signal is supplied to the control means 13
Is a signal indicating a predetermined command (for example, start of control, etc.) to the CD servo controller 21 or the WOBBLE servo controller 22 from the controller.

Then, a predetermined STATUS signal is input to the control means 13 from the CD servo controller 21. Further, a predetermined STATUS signal is input from the WOBBLE servo controller 22 to the control means 13.

The STATUS signal is a signal indicating a response to the command, that is, information indicating the control (for example, statuses such as control success, control failure, and control execution).

[Recording] Recording (writing) data (signal) on the optical disc 2
At this time, the pre-groove formed on the optical disc 2 is reproduced (read), and thereafter, data is recorded along the pre-groove.

When data (signal) to be recorded on the optical disk 2 is input to the optical disk device 1 via the interface control unit 31, the data is transmitted to the EFM / CRO.
It is input to the M encoder control unit 24.

In the EFM / CDROM encoder control unit 24, the data is encoded based on the clock signal from the clock 34 (at the timing of the clock signal), and is modulated by a modulation method called EFM (Eight to Fourteen Modulation). EFM modulation) and ENC
This is an ORDE EFM signal.

As shown in FIG. 3, this ENCODE
The EFM signal is a signal composed of pulses having a length (period) of 3T to 11T.

As shown in FIGS. 4 and 5, EF
In the M / CDROM encoder control unit 24, the clock 3
4 is divided to generate a SUBCODE-SYNC signal (subcode sync signal) composed of pulses of a predetermined cycle. This SUBCODE-SY
Cycle of NC signal pulse (interval between adjacent pulses)
Is 1/75 second at 1 × speed.

At the time of encoding, the synchronization signal, that is, the SYNC pattern (sync pattern)
Based on the BCODE-SYNC signal (SUBCODE
-At the timing of the SYNC signal), the ENCODE
It is added to the EFM signal. That is, SYNC is added to the portion corresponding to the head of each subcode frame.
A pattern is added.

The ENCODE EFM signal is generated by the EF
The data is input from the M / CDROM encoder control unit 24 to the laser control unit 14.

Also, WRITE P which is an analog signal
An OWER signal (voltage) is output from a D / A converter (not shown) built in
Is input to

The laser control unit 14 has an ENCODE E
On the basis of the FM signal, the WRITE
The level of the POWER signal is switched between a high level (H) and a low level (L) and output, whereby the driving of the laser diode of the optical head 3 is controlled.

More specifically, the laser control unit 14
While the level of the ORDE EFM signal is high (H), the level of the WRITE POWER signal is set to high (H) and output. That is, the output of the laser is increased (write output). And ENCODE
While the level of the EFM signal is low (L), the WRI
The level of the TE POWER signal is set to a low level (L) and output. That is, the output of the laser is reduced (return to read output).

As a result, the optical disc 2 has an ENCO
When the level of the RDE EFM signal is high (H), a pit of a predetermined length is written, and ENCODE EFM is written.
When the level of the FM signal is low (L), a land of a predetermined length is written.

In this way, data is written (recorded) on a predetermined track of the optical disc 2.

EFM / CDROM encoder control unit 24
In, a predetermined ENCODE EFM signal (random EFM signal) is generated in addition to the above-mentioned ENCODE EFM signal. This random EFM signal is output from the OPC (Opti
mum Power Control) is used for laser output adjustment (power control) at the time of test writing to the test area.

At the time of test writing in the test area in the OPC, the random EFM signal is generated by the EFM / CRO
The data is input from the M encoder control unit 24 to the laser control unit 14.

At the time of test writing in the test area in the OPC, the control means 13 generates a WRITE POWER signal of 15 levels and outputs the WRITE POWER signal.
The EPOWER signal is output from a D / A converter (not shown) built in the control unit 13 and input to the laser control unit 14.

Then, the laser control unit 14 receives the WRIT from the control unit 13 based on the random EFM signal.
The level of the E POWER signal is switched between a high level (H) and a low level (L) and output, thereby controlling the driving of the laser diode of the optical head 3. This is performed for each of the WRITE POWER signals of 15 levels.

In the OPC operation, the test writing to the test area is performed with the laser light of 15-step output in this way.

When data is written to the optical disk 2, a read-out laser beam is emitted from the laser diode of the optical head 3 to the pre-groove of the optical disk 2, and the reflected light is received by the divided photodiode of the optical head 3. Is done.

The WOBBLE signal shown in FIG. 6 is output from the divided photodiode. As described above, the WOBBLE signal includes a signal having a frequency of 22.05 kHz at 1 × speed, and a signal obtained by performing biphase modulation on ATIP information and further performing FM modulation at a carrier frequency of 22.05 kHz.

The WOBBLE signal is input to the WOBBLE signal detection circuit 19 and is binarized by the WOBBLE signal detection circuit 19.

The binarized WOBBLE signal is the WOB signal.
This is input to the BLE servo controller 22.

In the WOBBLE servo controller 22, the FM-modulated AT of the WOBBLE signal is used.
The IP information is demodulated to obtain a BIDATA signal (bi-phase data signal) shown in FIG. This BIDATA signal is a signal (pulse signal) of 1T to 3T. Note that this BIDATA signal is bi-phase demodulated and then decoded to obtain ATIP information.

The WOBBLE servo controller 2
2, a digital PLL circuit (not shown) generates a clock based on the BIDATA signal,
The BICLOCK signal shown in FIG. 7 is obtained. This BICLO
The CK signal is used for decoding timing of a BIDATA signal described later.

The BIDATA signal and the BICLOC
The K signals are input to the sync signal generation / ATIP decoder 27, respectively.

The sync signal generation / ATIP decoder 27 bi-phase demodulates the BIDATA signal based on the BICLOCK signal, and then decodes and decodes the ATIP signal.
Information is obtained, and an ATIP-SYNC signal (ATIP sync signal) shown in FIG. 7 is generated.

In this case, as shown in FIG.
When a SYNC pattern included in the A signal is detected, a pulse of the ATIP-SYNC signal is generated. The period of the pulse of the ATIP-SYNC signal (the interval between adjacent pulses) is 1/75 second at 1 × speed.

This ATIP-SYNC signal is input to each of the control means 13 and the WOBBLE servo controller 22.

The decoded ATIP information is input to the control means 13. The control means 13 grasps the absolute time on the optical disc 2 based on the ATIP information.

The SUBCODE-SYNC signal from the EFM / CDROM encoder control unit 24 is input to a sync signal generation / ATIP decoder 27.
And WOBBLE servo controller 22.

FIG. 8 is a diagram showing the format of an ATIP frame. As shown in the figure, the data of the ATIP frame is a 4-bit synchronization signal, that is, a sync (S
yn), an 8-bit minute (Min), an 8-bit second (Sec), an 8-bit frame, and a 14-bit error detection code (CRC: Cyclic Redundancy Code).

The WOBB servo controller 22 detects an error in the ATIP information for each ATIP frame (determines whether the ATIP information is incorrect).

In the error detection of the ATIP information, the ATI
"Normal" means that the result of performing a predetermined operation on the Sync, minute (Min), second (Sec) and frame data of the P frame matches the error detection code (CRC), Say "ATIP error."

In this case, as shown in FIG.
In the E servo controller 22, an error in the ATIP information,
That is, when an ATIP error is detected, a pulse 51 is generated and output.

ATIP E composed of this pulse 51
The RROR signal is input to a counter (counter) 131 of the controller 13. And this counter 13
1, the number of pulses of the ATIP ERROR signal becomes A
It is counted (measured) as a TIP error.

The error detection of the ATIP information is performed by the ATIP
Since it is performed for each frame, the ATIP error is 75 A
There are a maximum of 75 TIP frames (1 second at 1 × speed).

The WOBBLE servo controller 2
2 constitutes a detecting means for detecting an ATIP error.

The count value of the ATIP error is stored in the memory 26 and the interface control unit 3
1 and transmitted to the computer 41 for use in the inspection of the optical disk device 1 (determination of the recording capability of the optical disk device 1).

The ATIP-input to the control means 13
The SYNC signal is used for updating the ATIP time information.

The WOBBLE servo controller 2
2, the ATIP-SYNC signal is input to the SUBCO
Used for synchronization with the DE-SYNC signal.

SUBCODE input to the control means 13
The -SYNC signal is used for interpolation of ATIP time information and measurement of the ATIP error described above.

The WOBBLE servo controller 2
The SUBCODE-SYNC signal input to 2 is used as a reference signal for synchronization, like the ATIP-SYNC signal.

The synchronization is performed so that the position of the SUBCODE-SYNC signal in the EFM data generated at the time of writing substantially coincides with the position on the optical disk 2 where the ATIP-SYNC signal is generated.

As shown in FIG. 9, SUBCODE-SY
The difference between the NC signal and the ATIP-SYNC signal is usually
± 2E at each part of the entire optical disc 2
Up to FM frames are allowed.

[Reproduction] When reproducing (reading) data (signal) from the optical disk 2, the WRITE POW from the laser control unit 14 is used.
The level of the ER signal is a constant D corresponding to the read output.
The output is held at the C level, whereby the output of the laser is held at the read output. The read output (output of the main beam) is usually set to 0.7 mW or less.

When reading data from the optical disk 2,
A read output laser beam is radiated from a laser diode of the optical head 3 onto a predetermined track of the optical disc 2,
The reflected light is received by the split photodiode of the optical head 3.

Currents (voltages) corresponding to the amounts of received light are output from the respective light receiving portions of the divided photodiodes, and these currents, ie, each signal (detection signal) is
Each is input to the HF signal generation circuit 15 and the error signal generation circuit 18.

The HF signal generation circuit 15 generates an HF (RF) signal by adding or subtracting these detection signals.

The HF signal is an analog signal corresponding to pits and lands written on the optical disk 2.

This HF signal is input to the HF signal gain switching circuit 16 and is amplified. The amplification factor (gain) of the HF signal gain switching circuit 16 is
Is switched by a gain switching signal from the controller.

This amplified HF signal (hereinafter simply referred to as “HF signal”
Signal) is input to each of the peak / bottom detection circuit 17 and the CD servo controller 21.

Further, the peak / bottom detection circuit 17 includes:
A tracking error (TE) signal described in the focus control, tracking control, and sled control is input.

As shown in FIG. 10, the peak / bottom detection circuit 17 extracts an amplitude (envelope) of an input signal, for example, an HF signal or a tracking error signal.

The upper side of the amplitude is called PEEK (TOP), the lower side of the amplitude is called BOTTOM, the signal corresponding to the upper side of the amplitude is called a PEEK (TOP) signal, and the signal corresponding to the lower side of the amplitude is called a BOTTOM signal.

The PEEK signal and BOTTOM signal are
A (not shown) built in the control means 13
The signal is input to a / D converter, and is converted into a digital signal by the A / D converter.

The PEEK signal and the BOTTOM signal are used, for example, for amplitude measurement, amplitude adjustment of a tracking error signal, and β in OPC (Optimum Power Control).
It is used for calculating (β value), determining the presence or absence of an HF signal, and the like.

In the CD servo controller 21, the HF signal is binarized, EFM demodulated, and an EFM signal is obtained. This EFM signal is a signal composed of pulses having a length (period) of 3T to 11T.

The CD servo controller 21 responds to the EFM signal by a CIRC (Cross Interl
Error correction (CIRC error correction) using an error correction code called “eaved Read Solomon Code” is performed twice.

In this case, the first CIRC correction is called C1 error correction, and the second CIRC correction is called C2 error correction.

The case where the first CIRC correction, ie, the C1 error correction cannot be performed, is referred to as “C1 error”. The case where the second CIRC correction, ie, the C2 error correction cannot be performed, is referred to as “C2 error”.

As shown in FIG. 11, in the CD servo controller 21, when a C1 error is detected during the C1 error correction, a pulse 52 is generated and output.

C1ERROR composed of the pulse 52
The R signal is input to the counter 131 of the control means 13. The counter counts (measures) the number of pulses of the C1ERROR signal as a C1 error.

Since one subcode frame is composed of 98 EFM frames, the C1 error and the C2 error are
75 subcode frames each (1 second at 1x speed)
, There are a maximum of 7,350.

The CD servo controller 21 constitutes a detecting means for detecting a C1 error.

The count value of the C1 error is stored in the memory 26.
Is transmitted to the computer 41 via the interface control unit 31 and is used for the inspection of the optical disk device 1 (determination of the reproduction capability or the recording / reproduction capability of the optical disk device 1).

In the CD servo controller 21, the CIR
The EFM signal after the C error correction is decoded (converted) into data of a predetermined format, that is, a DATA signal.

[0108] Typically, audio data (music data) is recorded on the optical disc 2 and its EFM
A case where a signal is decoded into a DATA signal in an audio format will be described.

FIG. 12 is a timing chart showing the audio format DATA signal, LRCLOCK signal, and BITCLOCK signal.

As shown in the figure, in the CD servo controller 21, the EFM signal is composed of 16-bit L channel data and 16-bit R channel data based on the clock signal from the clock 33.
Decoded to ATA signal.

In the CD servo controller 21,
BITC based on the clock signal from clock 33
A LOCK signal and an LRCLOCK signal are generated, respectively. This BITCLOCK signal is a serial data transfer clock.

The LRCLOCK signal is a signal for distinguishing between L channel data and R channel data in the DATA signal. In this case, when the level of the LRCLOCK signal is high (H), it indicates L channel data, and when it is low (L), it indicates R channel data.

Even when ordinary data is recorded on the optical disk 2, the EFM signal is decoded into the above-mentioned DATA signal composed of 16-bit L-channel data and 16-bit R-channel data. .

The DATA signal, LRCLOCK signal and BITCLOCK signal are respectively
The data is input to the decoder control unit 28.

The CDROM decoder control unit 28 stores correction information, for example, ECC (Error Correc
If an error correction code of (Edtion Code) / EDC (Error Detecting Code) is recorded, the error correction is performed on the DATA signal.

This ECC / EDC is a CD-ROM M
This is an error correction code in the ODE1 format.
By this error correction, the bit error rate can be reduced to about 10 ⁻¹² .

In the CDROM decoder control unit 28, the DATA signal is decoded into data of a predetermined format for communication (transmission) based on the clock signal from the clock 35, and the decoded data (decoded data) is Is transmitted to the computer 41 via the interface control unit 31.

On the computer 41 side, for example, the decoded data is encoded, and the encoded data (encoded data) is recorded (copied) on a predetermined recording medium (for example, an optical disk).

Further, in the CD servo controller 21,
The FRAME SYNC signal shown in FIG. 13 is generated.

The level of the FRAME SYNC signal becomes a high level (H) when the HF signal is input to the CD servo controller 21 and the EFM signal is synchronized at a specified period (3T to 11T). And HF
When a signal (EFM signal) is not input (when synchronization is lost), FRAME S is output in EFM frame units.
The level of the YNC signal changes from a high level (H) to a low level (L).

The length (period) of one EFM frame
Is 136 μsec at 1 × speed, and 98 EFM frames are one subcode frame.

This FRAME SYNC signal is input to the control means 13 and used for detecting the end of the HF signal.

The SUBQ DATA signal is input from the CD servo controller 21 to the control means 13.

This SUBQ DATA signal is a signal indicating Q data of the subcode data.

The subcodes include P, Q, R, S, T,
There are eight types, U, V and W. One EFM frame has one byte of subcode, and one byte of each of the data P to W is recorded in one byte.

Each data of P to W is 1 bit, and one subcode frame is a 98 EFM frame. Therefore, each data of P to W in one subcode frame is 98 bits. However, the first 2EF
Since the M frame is used for a SYNC pattern (synchronization signal), the actual data is 96 bits.

FIG. 14 is a diagram showing a format of 96 bits of Q data. The controls (4 bits) of Q1 to Q4 shown in FIG. 6 are used for discriminating normal data / audio data.

Addresses Q5 to Q8 (4 bits)
Indicates the contents of data (72 bits) from Q9 to Q80.

The CRC (Cyclic R) of Q81 to Q96
The edundancy code (16 bits) is used for error (error) detection (determination of whether or not data is incorrect).

From the Q data, further, absolute time information on the optical disk 2, current track information, lead-in, lead-out, music number, and a table of contents called TOC (Table Of Contents) recorded in the lead-in. Contents and the like can be obtained.

The control means 13 obtains information from such Q data and performs predetermined control.

The SUBCODE-SYNC signal is input from the CD servo controller 21 to the control means 13.

As shown in FIG. 15, there are 98 bytes of subcode data in a 98 EFM frame. As described above, the two bytes of the first 2 EFM frames, ie, S0 and S1, have a SYNC pattern (synchronous signal ) Is recorded.

In the CD servo controller 21, this S
When the YNC pattern is detected, a pulse is generated and output. That is, one subcode frame (98EF)
For every M frames), a pulse is generated and output. The signal composed of this pulse is SUBCODE-SYN
This is the C signal. The SYNC pattern is detected 75 times per second at 1 × speed.

In the CD servo controller 21,
After detecting the pulse of the SUBCODE-SYNC signal, the above-described Q data is updated. Then, the updated Q data is read into the control means 13.

[Focus Control, Tracking Control, and Thread Control] The PU drive control signal generation circuit 18 performs addition and subtraction of the detection signals from the divided photodiodes described above, thereby obtaining a focus error (FE) signal and a tracking error (FE) signal. A TE) signal, a thread error (SE) signal, and a track loss (TLN) signal are generated.

This focus error signal is a signal indicating the magnitude and direction of the shift of the objective lens from the focus position in the direction of the rotation axis (the shift amount of the objective lens from the focus position).

The tracking error signal is a signal indicating the magnitude of the displacement of the objective lens in the radial direction from the center of the track (pre-groove) and its direction (the amount of displacement of the objective lens from the center of the track).

The thread error signal is an error (error) signal used for thread control, that is, thread servo (feed servo of the optical head body of the optical head 3). In other words, it is a signal indicating the magnitude and direction of the displacement of the optical head 3 in the radial direction (the feed direction of the optical head 3) from the target position (proper position) of the optical head 3. The focus error signal is input to the CD servo controller 21.

The tracking error signal is input to the CD servo controller 21 and also to the peak / bottom detection circuit 17 as described above. The thread error signal is output from the CD servo controller 2
1 is input.

Using the focus error signal, tracking error signal and thread error signal, the optical disc device 1 performs focus control, tracking control and thread control on a predetermined track.

At the time of focus control, the CD servo controller 21 performs focus PWM (Puls Width Modulation) control for driving the actuator 4 in the rotation axis direction.
) A signal is generated. This focus PWM signal is
It is a digital signal (continuous pulse).

The focus PWM signal is input from the CD servo controller 21 to the PWM signal smoothing filter 7 and smoothed by the PWM signal smoothing filter 7, that is, converted into a control voltage (control signal).
Is input to Then, the driver 6 applies a focus signal (predetermined voltage) to the actuator 4 based on the control voltage, and drives the actuator 4 in the rotation axis direction (focus direction).

In this case, the CD servo controller 21
Is to adjust the pulse width (duty ratio) of the focus PWM signal and invert the sign (positive or negative) of the focus PWM signal so that the level of the focus error signal becomes 0 (as much as possible). I do. Thereby, the objective lens of the optical head 3 is located at the focus position.
That is, focus servo is applied.

In the tracking control, the CD servo controller 21 generates a tracking PWM signal for controlling the radial driving of the actuator 4.
This tracking PWM signal is a digital signal (continuous pulse).

The tracking PWM signal is input from the CD servo controller 21 to the PWM signal smoothing filter 7, and is smoothed by the PWM signal smoothing filter 7.
That is, it is converted into a control voltage (control signal) and input to the driver 6. The driver 6 applies a tracking signal (predetermined voltage) to the actuator 4 based on the control voltage, and drives the actuator 4 in the radial direction (tracking direction).

In this case, the CD servo controller 21
The tracking PWM is adjusted so that the level of the tracking error signal becomes zero (as much as possible).
The pulse width (duty ratio) of the signal is adjusted, and the sign (positive or negative) of the tracking PWM signal is inverted. Thereby, the objective lens of the optical head 3 is located at the center of the track (pre-groove). That is, tracking servo is applied.

At the time of thread control, the CD servo controller 21 generates a thread PWM signal for controlling the drive of the thread motor 5. This thread PW
The M signal is a digital signal (continuous pulse).

The sled PWM signal is input from the CD servo controller 21 to the PWM signal smoothing filter 7, smoothed by the PWM signal smoothing filter 7, that is, converted into a control voltage (control signal), and input to the driver 6. You. The driver 6 sends a sled signal (predetermined voltage) to the sled motor 5 based on the control voltage.
To drive the thread motor 5 to rotate.

In this case, the CD servo controller 21
Is to adjust the pulse width (duty ratio) of the thread PWM signal and to reverse the sign (positive / negative) of the thread PWM signal so that the level of the thread error signal becomes 0 (as much as possible). I do. Thereby, the optical head main body of the optical head 3 is located at the target position (appropriate position). That is, the thread servo is applied.

It is to be noted that, in addition to tracking control, for example, the tracking error signal is transmitted to the optical head 3 from the optical disk 2.
When moving to a predetermined track (target track) of
That is, it is also used for track jump control and the like described later.

[Track Jump Control (Optical Head Movement Control)] In the optical disk device 1, when the optical head 3 is immediately moved from the current track of the optical disk 2 to the target track, that is, when the objective lens is moved to the target track. Track jump control is performed. In this track jump control, the thread motor 5 of the optical head body moving mechanism is used.
And the drive of the actuator 4 are controlled, and the objective lens of the optical head 3 is moved to the target track by rough search, fine search, or a combination thereof.

FIG. 16 is a block diagram (a diagram showing a main part in FIG. 2) of a portion for executing the track jump control.

As shown in the figure, detection signals a, b, c, d, e, f,
g and h are input to the PU drive control signal generation circuit 18, and the PU drive control signal generation circuit 18 detects the detection signals a to
By performing addition or subtraction of h, a tracking error signal (hereinafter, referred to as a TE signal) and a track loss signal (hereinafter, referred to as a TLN signal) are generated.

The TE signal and the TLN signal are input to the CD servo controller 21. The CD servo controller 21 sends a drive signal to the driver 6 based on the TE signal and the TLN signal.

The driver 6 includes a first driver 61 and a second driver 61.
And a driver 62. First driver 61
Sends a control signal to the sled motor 5 to drive the sled motor 5, and the second driver 62 sends a control signal to the actuator 4 to drive the actuator 4.

When performing track jump control, the CD
The servo controller 21 grasps a radial position and a moving direction of the optical head 3 (objective lens) with respect to the optical disc 2 based on the TE signal and the TLN signal (S1) generated by the PU drive control signal generation circuit 18. Then, the optical head 3 (objective lens) is moved to the target track.

Here, the number of tracks from the current track to the target track (hereinafter referred to as the number of target passing tracks)
Is relatively large, that is, when exceeds a preset reference value (threshold), rough search is performed. If the optical head 3 is not positioned on the target track at the time of completion of the rough search, then,
Fine search is performed, and by this fine search,
The optical head 3 is moved to a target track.

When the number of target tracks is relatively small, that is, when the number of tracks is smaller than the reference value, fine search is performed.
Is reliably moved to the target track. Hereinafter, the rough search and the fine search will be described in detail.

In the rough search, the CD servo controller 21 sends a drive signal to the first driver 61 while grasping the radial position of the optical head 3 (objective lens) based on the TE signal. As a result, a control signal is sent from the first driver 61 to the sled motor 5, the sled motor 5 is driven, and the optical head body moves in the radial direction. That is, the entire optical head 3 is moved to the target track by moving the optical head body. Hereinafter, this rough search will be described with reference to the schematic diagram shown in FIG.

FIG. 17 is a diagram showing a positional relationship between a divided photodiode and reflected laser light. FIG. 17 shows a state in which the main beam of the main beam and the two sub beams is irradiated on the pre-groove 72.

As shown in FIG.
Adopts a DPP method (Diffexential Push Pull) and uses a pre-groove 7 formed on the optical disc 2.
2 is irradiated with the main beam, and one land 73 adjacent to the pre-groove 72 is irradiated with one sub-beam, and the other land 74 adjacent to the pre-groove 72 is irradiated.
Is irradiated with the other sub-beam.

The reflected light of the main beam from the pre-groove 72 is transmitted to the light receiving sections 81 and 8 of the divided photodiodes.
2, 83 and 84, and the light receiving sections 81, 8
2, 83, and 84 output detection signals a, b, c, and d at levels corresponding to the amount of received light, respectively.

The reflected light of the sub-beam from the land 73 is received by the light receiving portions 85 and 86 of the divided photodiodes.
Detection signals e and f at levels corresponding to the amount of received light are output.

The reflected light of the sub beam from the land 74 is received by the light receiving portions 87 and 88 of the divided photodiodes.
Detection signals g and h at levels corresponding to the amount of received light are output.

The TE signal is represented by the following equation (1). Note that k in the following equation (1) is a constant.

TE signal = {(a + d) − (b + c)} − k {(e + g) − (f + h)} (1)

When the main beam is located at the center of the pregroove 72 or the lands 73 and 74,
(A + d) − (b + c) = k ｛(e + g) − (f +
h)｝, the level of the TE signal becomes 0 (0 level).

In performing the rough search, when the thread head 5 is driven to move the optical head 3 in the radial direction, the laser beam emitted from the optical head 3 becomes a pre-groove, a land, a pre-groove, and so on. , Crossing the pre-groove and land alternately. Since the reflectivity of the laser light is lower in the land than in the pre-groove, the light amount of the laser light reflected on the land is smaller than the light amount of the laser light reflected on the pre-groove. Therefore, the TE signal given by the above equation (1) becomes a wave-shaped (wave-shaped) signal shown in FIG. 18 as it moves in the radial direction, and the optical head 3 passes through one pregroove, that is, one track. Each time, one waveform (one cycle) is generated.

Accordingly, the number of peaks or valleys of the TE signal is represented by C
By counting with a counter (not shown) built in the D servo controller 21, the number of grooves that have passed, that is, the number of tracks that have passed, can be determined, whereby the optical head 3 can be moved to the target track.

For example, when the optical head 3 is moved by 1,000 tracks by the rough search, the thread head 5 is driven to move the optical head 3, and at the same time, the number of peaks or valleys of the TE signal shown in FIG. 18 is counted. Then, the thread motor 5 is stopped so that the counted value becomes 1000.

Next, the fine search will be described.
In the fine search, the CD servo controller 21
The position of the optical head 3 (objective lens) in the radial direction is determined based on the TLN signal, and the moving direction of the optical head 3 (objective lens) is determined based on the TE signal (phase difference between the TE signal and the TLN signal). The drive signal is sent to the second driver 62 while grasping. As a result, a control signal is sent from the second driver 62 to the actuator 4, and the actuator 4 is driven to move the objective lens in the radial direction.
Further, the CD servo controller 21
The drive of the thread motor 5 is controlled via the driver 61 so that the optical head main body follows the objective lens. As a result, the entire optical head 3 moves to the target track.

The TLN signal is represented by the following equation (2).
Note that k ′ in the following equation (2) is a constant.

TLN signal = (a + b + c + d) −k ′ (e + f + g + h) (2)

As shown in FIG. 17, when the main beam is located at the center of the pre-groove 72, the first term (a + b + c + d) on the right side of the above equation (2) becomes the maximum and the second term (e + f + g + h) ) Is minimum, so the level of the TLN signal is maximum.

The level of the TLN signal decreases as the main beam moves away from the center of the pregroove.
The level of the LN signal is at a minimum.

Therefore, when the optical head 3 is moved in the radial direction, the TLN signal S1 becomes a wave-shaped (wave-shaped) signal that fluctuates (vibrates) at a substantially constant cycle as shown in FIG. The TLN signal S1 has one waveform (1) each time the optical head 3 passes through one pre-groove, that is, one track.
Cycle) is generated. That is, the number of valleys (waves) of the TLN signal S1 corresponds to the number of tracks (the number of pre-grooves) that the optical head 3 has passed.
By counting with a counter (not shown) built in the D servo controller 21, the number of passed pre-grooves, that is, the number of passed tracks can be determined, whereby the optical head 3 can be moved to the target track.

For example, when the optical head 3 is moved by 50 tracks by fine search, the actuator 4 and the sled motor 5 are driven to move the optical head 3, and at the same time, the number of valleys of the TLN signal shown in FIG. Is counted, and the actuator 4 and the sled motor 5 are stopped so that the counted value becomes 50.

In PU drive control signal generation circuit 18, TL
Correction and binarization processing are performed on the N signals. That is, in a binarizing circuit 76 of the PU drive control signal generating circuit 18 described later, a predetermined reference level L1 is set in advance as shown in FIG.
By comparing 1 with the corrected level of the TLN signal, the TLN signal is binarized. The correction of the TLN signal will be described later in detail.

[Rotation Number Control (Rotation Speed Control)] In the optical disk device 1, for example, during recording and reproduction,
The rotation speed (rotation speed) of the spindle motor 8 is controlled. The method of controlling the number of rotations includes WOBBLEPWM
(Puls Width Modulation) signal, that is, a spindle servo (W) using a WOBBLE signal.
OBBLE servo) and a method of controlling with an FG PWM signal, that is, a spindle servo (F
G servo) and a method of controlling with an EFM PWM signal, that is, a spindle servo (EFM) using an EFM signal
Servo). Hereinafter, these will be sequentially described.

The WOBBLE PWM signal is WOBBL
This is a spindle motor control signal generated by the E servo controller 22. Specifically, it is a digital signal (continuous pulse) of 0-5V level.

This WOBBLE PWM signal corresponds to WOB
The signal is input from the BLE servo controller 22 to the PWM signal smoothing filter 12, smoothed by the PWM signal smoothing filter 12, that is, converted into a control voltage (control signal), and input to the driver 11. And driver 1
1 drives the spindle motor 8 to rotate based on the control voltage.

In this case, the WOBBLE servo controller 22 sets the pulse width (duty ratio) of the WOBBLE PWM signal so that the frequency (period) of the WOBBLE signal becomes a target value (for example, 22.05 kHz at 1 × speed). Adjust). Thus, the spindle servo is operated so that the rotation speed (rotation speed) of the spindle motor 8 becomes the target value.

The FG PWM signal is a spindle motor control signal generated by the control means 13. In particular,
It is a digital signal (continuous pulse) of 0-5V level.

This FG PWM signal is input from the control means 13 to the PWM signal smoothing filter 12, and the PWM signal is
The signal is smoothed by an M signal smoothing filter 12, that is, converted into a control voltage (control signal) and input to the driver 11. Then, the driver 11 drives the spindle motor 8 to rotate based on the control voltage.

On the other hand, from the Hall element 9, an FG (Frequenc) corresponding to the rotation speed (rotation speed) of the spindle motor 8 is obtained.
y Generator) signal is output. This FG signal is
The signal is binarized by a G signal binarization circuit 23 and input to a frequency measurement unit (period measurement unit) (not shown) of the control unit 13.

The frequency measuring section of the control means 13 measures the frequency (period) of the FG signal based on the clock signal from the clock 32. Then, the control means 13
The pulse width (duty ratio) of the FG PWM signal is adjusted so that the frequency (cycle) of the G signal becomes a target value. Thus, the spindle servo is operated so that the rotation speed (rotation speed) of the spindle motor 8 becomes the target value.

The EFM PWM signal is a spindle motor control signal generated by the CD servo controller 21. Specifically, it is a digital signal (continuous pulse) of 0-5V level.

The EFM PWM signal is input from the CD servo controller 21 to the PWM signal smoothing filter 12, and is smoothed by the PWM signal smoothing filter 12.
That is, it is converted into a control voltage (control signal) and input to the driver 11. Then, the driver 11 drives the spindle motor 8 to rotate based on the control voltage.

In this case, the CD servo controller 21
Adjusts the pulse width (duty ratio) of the EFM PWM signal such that the period of a predetermined pulse of the EFM signal, that is, the pulse having a period of 3T to 11T, becomes a target value. Thus, the spindle servo is operated so that the rotation speed (rotation speed) of the spindle motor 8 becomes the target value.

Next, the operation of the fine search will be described in detail. As mentioned earlier, in fine search,
By counting the number of valleys of the TLN signal S1 shown in FIG. 19, the position of the optical head 3 in the radial direction is grasped, and the optical head 3 is moved to the target track.

In this case, as described above, the reference level L
1, the reference level L1 is compared with the level of the TLN signal S1 to obtain the TLN signal S1.
Is binarized, and by counting the number of pulses of the binarized TLN signal, it is detected how many tracks have crossed during the fine search (track jump).

Here, in practice, the TLN signal S1 contains an offset component (DC component), and this offset component includes the ambient temperature, the change with time, the inclination of the optical head 3, the mounting state of the optical disk 2, and the like. Therefore, the TLN signal S1 does not always fluctuate at a constant amplitude with respect to the reference level L1.

As shown in FIG. 20, when the offset component increases, the TLN signal S1 changes to the reference level L1.
No longer intersects. In such a case, the TLN signal S
Since 1 cannot be properly binarized, the number of times the optical head 3 crosses the track cannot be accurately counted, and the optical head 3 cannot be moved to the target track. That is, the track jump of the optical head 3 cannot be performed correctly.

To solve this problem, for example, FIG.
A method of removing the offset component by installing the circuit shown in FIG. 1 on the output side of the TLN signal is considered. As shown,
In this circuit, since the offset component included in the TLN signal is removed by the capacitor C11 and the like, and the TLN signal is amplified thereafter, a TLN signal having a large amplitude centering on the reference level L1 can be obtained.

However, in the circuit shown in FIG. 21, since the responsiveness accompanying the output fluctuation is poor, once the amplitude of the TLN signal changes, it is affected by the change in the amplitude for a predetermined period.

For example, a CD-R may have a recording portion on which data is recorded and an unrecorded portion on which no data is recorded. When the optical head 3 passes through the recording portion, the amplitude of the TLN signal is increased. Becomes larger, and the amplitude of the TLN signal becomes smaller when passing through the unrecorded portion.

Therefore, as shown in FIG. 22, when the optical head 3 shifts from the recording portion to the non-recording portion, the TLN signal S1
Gradually fluctuates so that the center of vibration becomes the reference level. Therefore, even though the optical head 3 actually crosses the track, the TLN signal S1 changes to the reference level L1.
May not intersect, and the binarization accuracy is poor. For this reason, an error occurs in the number of tracks traversed by the optical head 3, and it may not be possible to accurately move to the target track.

FIG. 23 is a block diagram showing an embodiment of the TLN signal generation device of the optical disk device 1.

The TLN signal generation device 70 shown in FIG. 27 constitutes a part of the above-described PU drive control signal generation circuit 18, and includes a TLN signal generation circuit 75 for generating the above-described TLN signal and a TLN signal generation circuit. TLN from circuit 75
High boost filter (signal correction circuit) that corrects the signal
71, and a binarization circuit 76 for binarizing the TLN signal from the high boost filter 71.

The TLN signal generation circuit 75 includes an operational amplifier O
It comprises a differential amplifier 751 having P2 and the like.

The high-boost filter 71 is composed of resistors R1, R2, R3, R4, a capacitor C1, and an operational amplifier OP1. That is, a series connection circuit of the resistor R2 and the capacitor C1 is connected in parallel to the resistor R1, its output side is connected to the negative terminal of the operational amplifier OP1, and the negative terminal and the output side of the operational amplifier OP1 are connected to the resistor R3. Connected through. Further, a reference voltage Vref is applied to the positive input terminal of the operational amplifier OP1 via a resistor R4.

This high boost filter 71 is similar to that shown in FIG.
As shown in the figure, 10 Hz (first frequency) to 1 kHz
It has the characteristic that the amplification factor increases linearly in the (second frequency) frequency band, has an amplification factor of about 1 (0 dB) below 10 Hz, and about 5 times (14 dB) above 1 kHz. It has an amplification factor.

TLN generated by TLN signal generation circuit 75
The N signal is input to the high boost filter 71 and corrected by the high boost filter 71. That is, T
By passing the LN signal through the high boost filter 71, the DC component and the AC component of 10 Hz or less of the TLN signal pass through without being amplified, and the AC component of 1 kHz or more is amplified about five times.

Since the frequency of the TLN signal at the time of the track jump is usually about 2 to 3 kHz, only the necessary signal component is amplified about 5 times by passing the TLN signal through the high boost filter 71.

The T corrected by the high boost filter 71
As described above, the LN signal is input to the binarization circuit 76, and is binarized by the binarization circuit 76. Then, the binarized TLN signal is input to the CD servo controller 21 and used in fine search, as described above.

FIG. 25 is a diagram showing a TLN signal before passing through the high boost filter 71 (point P1 in FIG. 23).
FIG. 26 is a diagram showing the TLN signal after passing through the high boost filter 71 (point P2 in FIG. 23).

As shown in these figures, TLN after passing through high boost filter 71 (point P2 in FIG. 23)
The signal (FIG. 26) has a higher AC component level than the TLN signal (FIG. 25) before passing through the high boost filter 71 (point P1 in FIG. 23). Therefore, the TLN signal that has passed through the high boost filter 71 is not affected by the offset component included in the TLN signal.
It definitely crosses the reference level L1. As a result, the TLN signal can be binarized with high accuracy, and the number of times the optical head 3 crosses the track can be reliably counted during the fine search, so that the accuracy of the fine search can be significantly improved. it can. The optical head 3 can be moved to the target track with high accuracy even when the optical disk 2 has not been recorded or the optical disk 2 has a recorded portion and an unrecorded portion.

[0209] The amplification factor of the AC component of the first frequency and the second frequency in the high boost filter 71,
The first frequency and the second frequency (frequency band) correspond to the magnitudes of the resistors R1 to R3 and the capacitor C1 respectively.
It is possible to arbitrarily adjust (set) by changing a predetermined one of the capacities.

The optical disk device of the present invention is compatible with the aforementioned CD.
-R drive device, other than this, for example, CD-R
Various optical disk devices for recording and reproducing optical disks having a pre-groove such as W, DVD-R, DVD-RAM,
The present invention can be applied to various optical disk devices for reproducing optical disks such as CDs (compact disks) and CD-ROMs.

The TLN signal generation device and the optical disk device of the optical disk device according to the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this. Any configuration having a function can be used.

For example, in the above embodiment, a high-boost filter is used as a signal correction circuit. However, the signal correction circuit according to the present invention is not limited to this.
Without removing the DC component included in the TLN signal,
Any circuit may be used as long as it amplifies the AC component included in the LN signal.

[0213]

As described above, according to the TLN signal generation device and the optical disk device of the optical disk device of the present invention, the AC component of the TLN signal is removed without removing the DC component of the track loss signal (TLN signal). Since the TLN signal is amplified, the TLN signal can be binarized with high accuracy without being affected by the offset component included in the TLN signal, with good responsiveness accompanying the fluctuation in the amplitude of the TLN signal.

Then, based on the TLN signal, the position of the optical head with respect to the optical disk in the radial direction is grasped, and when the optical head is moved to the target track, the number of times the optical head crosses the track must be counted. Can be
The optical head can be accurately moved to the target track.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a state where an optical disk device of the present invention is connected to a computer.

FIG. 2 is a block diagram showing an embodiment of the optical disk device of the present invention.

FIG. 3 is a timing chart showing an ENCODE EFM signal from an EFM / CDROM encoder control unit and an ENCODE EFM signal from a laser control unit according to the present invention.

FIG. 4 shows an ATIP-SYNC signal according to the present invention and SUBCODE from a sync signal generation / ATIP decoder;
6 is a timing chart showing a -SYNC signal and an ATIP ERROR signal.

FIG. 5 shows an ATIP-SYNC signal according to the present invention and a SUBCODE from a sync signal generation / ATIP decoder.
-SYNC signal and SU from CD servo controller
6 is a timing chart showing a BCODE-SYNC signal.

FIG. 6 shows 1T Biphase ATI according to the present invention.
P timing, WOBBLE signal, WO after binarization
6 is a timing chart showing a BLE signal.

FIG. 7 shows a BIDATA signal and BICL according to the present invention.
5 is a timing chart showing an OCK signal and an ATIP-SYNC signal.

FIG. 8 is a diagram showing a format of an ATIP frame according to the present invention.

FIG. 9 shows an ATIP-SYNC signal and S
6 is a timing chart showing a UBCODE-SYNC signal.

FIG. 10 shows an input signal to a peak / bottom detection circuit according to the present invention, the amplitude (envelope) of the input signal,
6 is a timing chart showing a PEEK signal and a BOTTOM signal.

FIG. 11 is a timing chart showing a SUBCODE-SYNC signal and a C1ERROR signal from a CD servo controller according to the present invention.

FIG. 12 is a timing chart showing a DATA signal, an LRCLOCK signal, and a BITCLOCK signal in an audio format according to the present invention.

FIG. 13 shows a SUBCODE-SYNC signal from a CD servo controller and FRAME SY in the present invention.
6 is a timing chart showing an NC signal and an HF signal (EFM signal).

FIG. 14 is a diagram showing a format of 96 bits of Q data according to the present invention.

FIG. 15 is a diagram showing one subcode frame in the present invention.

FIG. 16 is a block diagram (a diagram showing a main part in FIG. 2) of a portion for performing track jump control in the present invention.

FIG. 17 is a diagram showing a positional relationship between a divided photodiode and reflected laser light according to the present invention.

FIG. 18 is a characteristic diagram illustrating an example of a tracking error signal.

FIG. 19 is a diagram illustrating an example of a track loss signal.

FIG. 20 is a diagram illustrating a state where a track loss signal does not cross a reference level due to the presence of an offset component.

FIG. 21 is a diagram illustrating a circuit that removes a DC component of a track loss signal and amplifies only an AC component.

FIG. 22 is a diagram showing a change in an output signal from the circuit when the amplitude of a track loss signal changes in the circuit shown in FIG. 21;

FIG. 23 is a block diagram illustrating an embodiment of a TLN signal generation device according to the present invention.

FIG. 24 is a graph showing a frequency characteristic of an amplification factor of the high boost filter according to the present invention.

FIG. 25 is a diagram showing a track loss signal before passing through a high boost filter according to the present invention.

FIG. 26 is a diagram showing a track loss signal after passing through a high boost filter according to the present invention.

FIG. 27 is a diagram schematically showing a pregroove formed on an optical disc and lands formed on both ends thereof.

FIG. 28 is a diagram showing a track loss signal and a reference level.

[Explanation of symbols]

 Reference Signs List 1 optical disk device 10 casing 2 optical disk 3 optical head (optical pickup) 4 actuator 5 thread motor 6 driver 61 first driver 62 second driver 7 PWM signal smoothing filter 8 spindle motor 9 Hall element 11 driver 12 PWM signal smoothing filter 13 control means 131 Counter 14 Laser control unit 15 HF signal generation circuit 16 HF signal gain switching circuit 17 Peak / bottom detection circuit 18 PU drive control signal generation circuit 19 WOBBLE signal detection circuit 21 CD servo controller 22 WOBBLE servo controller 23 FG signal binarization circuit 24 EFM / CDROM encoder control unit 25, 26 memory 27 sync signal generation / ATIP decoder 28 CDROM decoder control unit 29 Lee 31 Interface controller 32 to 35 Clock 36 Address / data bus 41 Computer 42 Keyboard 43 Mouse 44 Monitor 51, 52 Pulse 70 TLN signal generator 71 High boost filter 72 Pregroove 73, 74 Land 75 TLN signal generator 751 Differential Amplifier 76 Binarization circuit 81 to 88 Light receiving section 101a, 101b Pregroove 102a, 102b Land 103a to 103c Reflected light S1 TLN signal L1 Reference level L2 Level OP1, OP2 Operational amplifier R1 to R4 Resistance C1, C11 Capacitors P1, P2

Claims (6)

[Claims] 1. A TLN signal generation circuit for generating a TLN signal (track loss signal) based on a signal from an optical head of an optical disk device; A signal correction circuit for amplifying an AC component included in the TLN signal without removing the TLN signal. 2. The signal correction circuit according to claim 1, wherein the signal correction circuit does not remove a DC component and an AC component having a frequency equal to or lower than a first frequency included in the TLN signal generated by the TLN signal generation circuit.
A second frequency higher than the first frequency included in the TLN signal;
2. The TLN signal generation device for an optical disk device according to claim 1, wherein the TLN signal generation device is configured to amplify an AC component having a frequency equal to or higher than the frequency. 3. The TLN signal generation device for an optical disk device according to claim 1, wherein the signal correction circuit includes a high boost filter. 4. The TL amplified by the signal correction circuit
The level of the TLN is compared with the reference level.
4. A circuit according to claim 1, further comprising a binarizing circuit for binarizing the signal.
A TLN signal generation device for an optical disk device according to any one of the above. 5. The T according to claim 1, wherein
An optical disk device comprising an LN signal generation device. 6. An optical head having an optical head and an optical head moving mechanism for moving the optical head, wherein the optical head moves in a radial direction of the optical disk with respect to the optical disk based on a TLN signal obtained from the TLN signal generating device. 6. The optical disk device according to claim 5, wherein the optical disk device is configured to determine the position of the optical disk.