JP2001209949A - Seek control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize stable seek operation in a lead-in region even when a ROM recording medium and a recoding medium for recording having a recorded region in the lead-in region are used in combination. SOLUTION: The seek controller which controls the seek operation by moving a head in a direction crossing tracks to the lead-in regions respectively formed on the ROM recording medium having reproduction interchangeability and the recordable recording medium having the recorded region in the lead-in regions has a discriminating means for discriminating the kinds of the ROM or recordable recording medium and a control means used selectively for the movement of feed by the counting operation of the number of the tracks to be crossed by the head in seeking to the lead-in region and the movement of feed of the head by a fixed voltage in the seeking by discrimination of the recording medium for recording by the discriminating means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direction crossing a track on an optical information recording medium centered on an optical disk, which can record and reproduce information signals at high speed and high density by an optical method using a laser beam. More particularly, the present invention relates to a seek control method for controlling a seek operation for moving an optical head, particularly, for example, in a so-called DVD (digital video disk or digital versatile disk), a DVD-ROM that is a read-only optical disk, and a write that is a recordable optical disk. The present invention relates to a seek control method suitable for controlling a seek operation of a recording / reproducing head, such as a DVD-R made of an organic dye material for once and a DVD-RW (DVD rewritable) made of a phase-change material that can be repeatedly recorded. is there.

[0002]

2. Description of the Related Art In recent years, DVD-Rs and DVD-Rs have been developed as write-once (hereinafter referred to as write-once) or rewritable DVDs.
RW and the like have been developed or partially commercialized.

[0003] In these write-once optical disks such as DVD-R and DVD-RW, tracks are formed by lands or grooves formed on the recording surface in advance, and the recording film is irradiated by irradiating the tracks with laser light. The data is recorded by changing the reflection characteristics of the data. Therefore, this write-once optical disc is a read-only DVD.
-This is a standard that is compatible with ROM and physical standards.
In such write-once optical discs such as DVD-R and DVD-RW, an area pre-recorded for copyright protection is in a control data area which is a lead-in area. Can be read out by pre-writing in the same manner as in normal recording, but cannot be read out in DVD-RW since this area is formed as embossed pre-pits as pits as a normal method. However, as proposed by the present applicant in Japanese Patent Application No. Hei 11-236629, there are discs configured to be able to read this area, and in such a disc, it is necessary to appropriately read a readable area. is there. Further, in order to perform tracking and recording / reproduction in this area in the recording apparatus, the head can be sought or positioned by using a push-pull or a differential push-pull (or a differential push-pull method) as a tracking method. Therefore, recording and reproduction can be performed without any problem.

[0004]

However, when the reproduction compatibility of the above-mentioned disc is attempted with a DVD-ROM drive or DVD video player which is a reproduction-only machine, a phase difference of a generally used tracking method is used. In the case of using the tracking method, an offset or a fluctuation in amplitude occurs in the tracking error signal, and a problem may occur in that section in which seek and positioning of the head cannot be performed well.

In addition, DVD-R and DVD-RW
For example, in a reproducing apparatus for reproducing data from a write-once optical disc, the optical head is moved at a high speed to a desired track position on the optical disc (by moving a laser spot on the disc in the radial direction of the disc at a high speed, for example). In order to determine the amount of movement of the optical head (laser spot), the number of tracks traversed by the optical head (laser spot) is counted. is necessary.

As described above, a write-once optical disc such as a DVD-R or a DVD-RW causes an offset or a fluctuation in a tracking error signal with respect to a read-only DVD-ROM. Even when the head seeks the recordable area, the number of tracks traversed by the laser spot can be counted, but when the head seeks the recorded area, the number of tracks traversed by the laser spot may not be accurately counted. There has been a problem that reproduction is interrupted due to a seek error, and good reproduction is not performed, and in the worst case, accurate reproduction cannot be performed from a disc.

The present invention has been made in view of the above-mentioned problems, and is intended for use in a case where a recorded area exists on a write-once optical disc, even if the optical disc to be reproduced is read-only. Even if there is, it is an object of the present invention to provide a seek control method capable of realizing a stable seek operation.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, tracks formed on a recording medium having recordable areas on both sides of a pre-recorded area are respectively provided. In the seek control method of moving the head in a direction crossing the head, when seeking the head from the unrecordable area to the track of the recorded area, or when traversing the recorded area from the first recordable area. Determining the type of the recording medium when seeking the head to a second recordable area by
Changing the seek control method of the head according to the result of the type determination of the recording medium. In order to solve the above-mentioned problems, the present invention is to traverse tracks formed on a recordable recording medium having recordable areas on both sides of a previously recorded area. In a seek control method in which a head is moved by using a tracking error detection method of a phase difference method, when the head is sought from the recordable area to a track in the recorded area, or the recording is performed from a first recordable area. Changing the seek control method so as to correspond to the offset or amplitude fluctuation of the tracking error detection signal in the recorded area when seeking the head to the second recordable area across the recorded area. And a seek control method comprising:

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a seek control method according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of an optical disk apparatus as an embodiment to which a seek control method according to the present invention is applied. In the embodiment of the present invention, for example, so-called MPEG2 is adopted as a compression / expansion technique for video and audio data, and a rewritable DVD is used as an example of an optical disc.
An RW disc will be described as an example. FIG.
In this configuration, many parts normally provided in a so-called DVD device or the like are omitted.

In FIG. 1, an optical disk 1 is a recording type optical disk made of, for example, a phase change material. In this embodiment, for example, a DVD-RW disk is used. In the DVD-RW disc, sectors (tracks) are spirally arranged in the disc, the rotation is controlled at a constant linear velocity (CLV), and one block is composed of 16 consecutive sectors. The block is a unit of processing for error correction (ECC block). The data amount of one round of the disk is equivalent to 2 ECC blocks on the inner circumference of the disk.
It is about 4 ECC blocks on the outer circumference. The optical disc 1 is attached to the spindle motor 2 by a chucking mechanism (not shown).

The spindle motor 2 is driven to rotate by a driver 7, and rotates the optical disk 1 chucked by a chucking mechanism. Although not shown, the spindle motor 2 is provided with a rotation position signal detecting means such as an FG generator and a Hall element. The FG signal from the FG generator and the rotation position signal from the Hall element are fed back to the servo unit 8 via the driver 7 as a rotation servo signal.

Although the optical head 3 is not shown, for example, a semiconductor laser is used as a light source, a laser spot is formed on a predetermined track of the optical disk 1 by a collimator lens, an objective lens, and the like, and a biaxial actuator is used. By driving the objective lens, focusing and tracking of the laser spot are performed. The semiconductor laser is driven by a laser drive circuit, and the biaxial actuator is driven by a driver 7.

The key input unit 10 includes a plurality of keys operated by a user, and sends key operation input information from the user to the system controller 9. That is, from the key input unit 10, for example, various key operation input information for instructing recording start, reproduction start, recording stop, reproduction stop, pause, and the like can be input by the user.

The interface unit 13 is an interface for transmitting and receiving data to and from a computer or the like.
face) interface.

The system controller 9 includes a key input unit 1
As key operation input information from 0, for example, according to various key operation input information such as recording start, reproduction start, recording stop, reproduction stop, and pause, LSI (signal processing unit) 5, servo section 8, amplifier section 4,
AV encoding / decoding unit 6). In addition, data is transmitted and received via the interface unit 13.

Here, for example, when a signal is reproduced from the optical disk 1, a reproduction start command is issued from the key input unit 10, and the system controller 9 at this time responds to the reproduction start command, which will be described later. Amplifier (AMP)
4. Control the servo unit 8 and the driver 7. That is,
When a signal is reproduced from the optical disc 1, the system controller 9 first rotates the optical disc 1 and irradiates a laser spot onto the optical disc 1 while rotating the optical disc 1.
An address signal formed in advance on a signal track on the optical disc 1 is read, a type is determined from the address and a disc ID (disc type information) recorded on the optical disc 1, and an object to be reproduced from the address information. The sector (track) is found, and the optical head 3 is moved so that the laser spot is located on the target sector (track). After the movement to the target sector is completed, signal reproduction from the target sector is started.

An amplifier unit 4 during reproduction of the optical disk 1 amplifies an RF signal reproduced from a target sector of the optical disk 1 by the optical head 3, and reproduces a reproduction signal, a tracking servo signal and a focusing servo signal (from this RF signal). Tracking error and focus error signals)
Generate The amplifier unit 4 includes at least an equalizer for optimizing the frequency characteristic of the reproduced signal, a PLL (phase locked loop) circuit for extracting a bit clock from the reproduced signal and generating a speed servo signal, and
A jitter generator for extracting a jitter component from a comparison between the bit clock from the L circuit and the time axis of the reproduced signal. The jitter value generated by the amplifier unit 4 is sent to the system controller 9, and the tracking servo, focusing servo signal and speed servo signal are transmitted to the servo unit 8.
Then, the reproduced signal is sent to the signal processing unit 5.

The servo section 8 receives the speed servo signal from the amplifier section 4, the focusing servo and tracking servo signals of the optical head 3, and also receives the rotation servo signal from the spindle motor 2, and based on these servo signals, Then, the servo control of the corresponding parts is performed. More specifically, the servo unit 8 controls the spindle motor 2 based on a speed servo signal generated by the PLL circuit of the amplifier unit 4 according to the disk rotation speed and a rotation servo signal from the spindle motor 2. A rotation speed servo control signal is generated so as to rotate the optical disk at a predetermined rotation speed, that is, to rotate the optical disk at a predetermined constant linear speed. Further, the servo unit 8 generates an optical head servo control signal for the optical head 3 to accurately perform focusing and tracking on the optical disc 1 based on the focusing and tracking servo signals. The rotation speed servo control signal and the optical head servo control signal are sent to the driver 7.

The driver 7 operates on the basis of each servo control signal supplied from the servo unit 8 and drives the spindle motor 2 to rotate in accordance with the rotational speed servo control signal from the servo unit 8, and also drives The two-axis actuator of the optical head 3 is driven according to the optical head servo control signal from the servo unit 8. In the present embodiment, the driver 7 drives the spindle motor 2 in accordance with the rotation speed servo control signal, thereby rotating the optical disc 1 at a predetermined linear speed.
Is the optical head 3 according to the optical head servo control signal.
By driving the axis actuator, focusing and tracking of the laser spot on the optical disk are performed.

The signal processing unit 5 when reproducing the optical disk 1
The reproduction signal supplied from the amplifier unit 4 is A / D (analog / digital) converted, a synchronization is detected from the digital signal obtained by the A / D conversion, and a so-called EFM + signal applied to the digital signal is performed. (8-16 modulated signal) is decoded into NRZ (Non Return to Zero) data, and error correction processing is further performed to obtain address data of a sector on the optical disc 1 and reproduction data. The address data and the synchronization signal obtained by the signal processing unit 5 are sent to the system controller 9. The details of the error correction processing performed by the signal processing unit 5 will be described later.

Here, the reproduced data is, for example, MPEG.
If the data is compression-encoded at a variable transfer rate, the optical disk device of this embodiment temporarily stores the data in a 256-Mbit D-RAM (track buffer memory 14), By controlling the writing / reading of 14, the time variation of the variable transfer rate of the reproduced data is absorbed. Note that the track buffer memory described in the present embodiment is a buffer memory for temporarily storing compressed data, for example, a buffer for absorbing a variable transfer rate generally provided in a DVD. Including memory. The management of the storage capacity and storage area of the track buffer memory 14 and the write / read control are performed by the system controller 9 via the signal processing unit 5, for example. The reproduction data read from the track buffer memory 14 is transmitted to the AV
It is sent to the encoding / decoding unit (A-V ENDEC) 6.

The AV encoding / decoding unit 6 at the time of reproducing the optical disc 1 is a data in which the reproduction data supplied from the track buffer memory 14 is compression-encoded by, for example, MPEG2 and audio data and video data are multiplexed. At one time, the multiplexed compressed audio data and compressed video data are separated, and
The data is decompressed and decoded in 2 and further subjected to D / A (digital / analog) conversion and output from a terminal 11 as an audio signal and a video signal. The video signal output from this terminal 11 is supplied to an NTSC (National Television not shown).
(System Committee) Processed by an encoder or the like and displayed on a monitor device, and the audio signal is sent to a speaker or the like (not shown) and emitted. The speed of the decompression decoding by the AV encoding / decoding unit 6 at the time of this reproduction is set to a decompression rate corresponding to the recording mode set at the time of recording. In other words, the AV encoding / decoding unit 6 is capable of performing expansion / decoding processing according to a plurality of expansion rates, determines the expansion rate in accordance with a recording mode set at the time of recording, and determines the expansion rate at that rate. Perform decompression decoding. The information of the recording mode is recorded on the optical disk 1 together with the recording data as control data. The control data is read out when the optical disk 1 is reproduced and sent to the system controller 9.
Sets the decompression rate of the AV encoding / decoding unit 6 based on the control data. The D / A conversion can be performed outside the AV encoding / decoding unit 6.

On the other hand, when recording a signal on the optical disk 1, for example, a recording start command is issued from the key input unit 10, and the system controller 9 responds to the recording start command by the amplifier unit 4 and the servo unit 8. And the driver 7. That is, when performing signal recording on the optical disc 1, first, the optical disc 1 is rotated and a laser spot is irradiated on the optical disc 1, and an address signal formed in advance on a signal track on the optical disc 1 is read. The target sector (track) to be recorded is found from the address information, and the optical head 3 is moved so that the laser spot is arranged on the target sector (track). Also, an audio signal and a video signal to be recorded are input from the terminal 11, and these signals are sent to the AV encoding / decoding unit 6.

At the time of recording on the optical disk, the AV encoding / decoding section 6 converts the audio signal and the video signal into A / D signals.
After the conversion, the audio data and the video data are compression-encoded by MPEG2 at a speed corresponding to the recording mode, and are further multiplexed and sent to the signal processing unit 5. That is, the AV encoding / decoding unit 6 can perform compression encoding at a plurality of compression rates according to the recording mode.

It should be noted that, for example, D having a storage capacity of 64 Mbits
The RAM 15 is a memory for temporarily storing data when the AV encoding / decoding unit 6 performs compression / expansion. The D-RAM 15 may have a storage capacity of 128 Mbits or 256 Mbits. Also, A
The / D conversion can be performed outside the AV encoding / decoding unit 6.

The optical disk apparatus of this embodiment can record and reproduce still image information and data such as a program file on a computer in addition to video and audio information. In this case, data such as still image information and a program file is supplied from the interface unit 13, and the data is sent to the signal processing unit 5 via the system controller 9.

In the signal processing unit 5 during recording on the optical disk,
An error correction code is added to the compressed data from the AV encoding / decoding unit 6 and data such as a program file via the system controller 9 to perform NRZ and EFM + encoding, and further supplied from the system controller 9. Recording data is generated by adding a synchronization signal.

Here, after the recording data is temporarily stored in the track buffer memory 14, it is read from the track buffer memory 24 at a reading rate corresponding to the recording rate on the optical disk 1. The recording data read out from the track buffer memory 14 is subjected to a predetermined modulation process in the signal processing unit 5, sent to the amplifier unit 3 as a recording signal, and is sent to the target sector ( Track).

At this time, the system controller 9
A / D (analog / digital) converts the jitter value supplied from the amplifier unit 4 for measurement, and changes the waveform correction amount in the amplifier unit 4 during recording according to the measured jitter value and the asymmetry value. That is, when a signal is recorded on the optical disk 1, the amplifier unit 4 corrects the waveform of the signal from the signal processing unit 5 and sends the corrected signal to the laser drive circuit of the optical head 3.

FIG. 2 is a diagram showing an example of a configuration of a servo system applicable to the embodiment of the present invention. FIG. 2 is an extracted configuration of a servo signal generation unit provided in the amplifier unit 4 of FIG. Is shown. FIG. 3 shows a DVD-R and a DVD-R
FIG. 3 shows signal waveforms at various parts when reproduced on a W-disk. In particular, FIG. 3 shows a DPD (differential phase) in a recorded area and a recordable area when reproduced on a DVD-R or DVD-RW disc. (Detection) tracking error signal.

In FIG. 2, the terminal 21 is connected to the optical head 3.
, For example, an output signal from a multi-segment photodetector is supplied. Each output signal from the multi-segment photodetector of the optical head 3 is
By performing a predetermined matrix operation in 2, R
Output as an F signal, and a focus error signal generator 2
3, a disc type detection section 24, an off-track signal generation section 25, a differential phase detect (hereinafter, appropriately referred to as DPD) signal generation section 26, a push-pull (hereinafter, appropriately referred to as PP) or a differential push-pull ( (Hereinafter, appropriately referred to as DPP).

The focus error signal generation section 23 generates a focus error signal FE from the RF signal from the matrix amplifier 22 and sends the focus error signal FE to the servo section 8 from the terminal 30.

The disc type detecting section 24 includes a read-only optical disc (DVD-ROM) and a recording (write-once).
Optical disk (DVD-R) for recording (rewritable)
And discriminating at least three types of optical disks (DVD-RW), and an RF signal from the matrix amplifier 22 is supplied. That is, the disc type detection unit 24 makes a determination based on the difference between the reflectances of the three types of optical discs, DVD-ROM, DVD-R, and DVD-RW, and the presence or absence of wobble. Specifically, the reflectivity of the DVD-ROM is high, the track is not wobbled, so there is no wobble, the reflectivity of the DVD-R is high, the track is wobbled, there is a wobble, and the DVD-R Since the reflectivity of the RW is low and the track is wobbled, each disc is identified from the feature that wobble is present. That is, if the reflectance is low among the three types of discs, the disc is detected as a DVD-RW. Also, R
The presence / absence of a wobble signal included in the F signal is detected, and if no wobble signal is detected, the DVD-ROM is determined. The remaining disk is determined to be a DVD-R.
Thus, three types of disks can be distinguished.

As described above, the disc type detection unit 24
A disc type detection signal DISCDET corresponding to the discrimination result of the type disc is output. The disc type detection signal DISCDET is sent from the terminal 31 to the servo section 8.

It should be noted that the above-described method of detecting the disk type (type) is merely an example, and the disk type (type) information recorded on the disk in advance can be detected. It may be.

In this embodiment, the tracking error signal T
As E, two types of tracking error signals are generated. One is a so-called differential phase detect (DPD) signal, and the other is a so-called push-pull (PP) or differential push-pull (DPP) signal. In this example, of these two signals, the DPD signal is used as the tracking error signal TE during reproduction, and the PP or DPP signal is used as the tracking error signal TE during recording.

That is, in the optical disk device of the present embodiment, the DPD signal generation section 26 generates a DPD signal from the RF signal from the matrix amplifier 22,
The P signal generation unit 27 generates a PP signal or a DPP signal from the RF signal from the matrix amplifier 22,
The D signal, the PP signal or the DPP signal is sent to the switch 28. The switch 28 is connected to the servo unit 8 via the terminal 35.
In response to the recording / reproduction select signal supplied from the controller, any one of the DPD signal, PP, and DPP signal is switched and output as the tracking error signal TE. More specifically, when the recording / reproduction select signal supplied from the servo unit 8 via the terminal 35 indicates that recording is being performed, the switch 28 is supplied from the PP / DPP signal generation unit 27. PP signal or DPP
The signal is output as a tracking error signal TE. On the other hand, when the recording / reproduction select signal indicates that the reproduction is being performed, the switch 28 sets the DPD signal generation unit 26
Is output as a tracking error signal TE.

The output from the switch 28 during the seek operation becomes a tracking error signal TE, which is sent from the terminal 33 to the servo section 8. The DPD signal is offset-controlled by OFS D / A and GA by a D / A converter of the servo unit 8 described later.
The gain control based on IND / A is configured to be variable.

The off-track signal generator 25 generates an off-track signal OFTR having a phase substantially 90 degrees different from the tracking error signal TE from the RF signal from the matrix amplifier 22, and the off-track signal OFTR
From the terminal 32 to the servo section 8. In the off-track signal generation section 25 of the present embodiment, the reflected light amount signal when the laser spot is formed at a position deviated from the track center on the optical disc is compared with a predetermined reference voltage. By doing so, the off-track signal OF
TR is being generated. However, the off-track signal OFTR
The method of generating is not limited to this example, but may be any other method. Any method can be used as long as a signal having a phase difference of approximately 90 degrees with respect to the tracking error signal TE can be generated.

In the track cross signal generator 29, the tracking error signal TE output from the switch 28
Is compared with a predetermined reference voltage to generate a track cross signal TKC as shown in FIG. That is, the track cross signal T shown in FIG.
KC is a signal composed of a pulse corresponding to a laser spot crossing a track. The track cross signal TKC is sent to the servo section 8 via the terminal 34. For example, as shown in FIG. 3, a TKC signal is obtained by comparing (comparing) a DPD signal, which is a tracking error signal when reproducing a DVD-R disc, with Vref, which is a predetermined reference voltage. Similarly, as shown in FIG. 3, a TKC signal is obtained by comparing (comparing) a DPD signal which is a tracking error signal when reproducing a DVD-RW disc with a predetermined reference voltage Vref.

As described above, the servo section 8 performs focus servo control based on the focus error signal FE supplied from the amplifier section 4, and performs tracking servo control based on the tracking error signal TE.

Further, seek control of the pickup (optical head 3) is performed by the configuration shown in FIG. The track counting section 44 counts the number of tracks crossed by the optical head 3 (laser spot) based on the track cross signal TKC supplied from the amplifier section 4 via the terminal 34.

That is, in the track counting section 44,
By counting the number of pulses of the track cross signal TKC, it is measured how many tracks the optical head 3 (laser spot) has moved in either the outer circumferential side or the inner circumferential side of the optical disk. . In the seek control, a voltage to be supplied to the tracking coil for driving the objective lens is generated from a signal corresponding to the number of movements from the system controller 9 by the seek control signal unit 41 with reference to a table, and the optical head 3 (laser spot) is generated. The number of tracks traversing in the radial direction of the optical disk is obtained from the track counting section 44, and this difference signal (the difference signal between the voltage supplied to the tracking coil and the signal corresponding to the number of traversed tracks) is amplified by the TD amplifier 42. It is driven by the driver 7 shown in FIG. The block of the seek control signal 41 receives a seek number signal from the system controller 9, generates a predetermined forced acceleration signal and a forced deceleration signal of a reference speed target value from a seek table, and obtains the number of seek signals from the track count 44. The error of the current speed with respect to the target is added from the signal and the speed signal generated from the cycle of the number signal, and the acceleration and deceleration signals are generated with a predetermined gain or offset coefficient to control the speed and the position.

In addition, the difference signal output from the seek control signal section 41 for making the objective lens of the laser spot and the optical head 3 mounted with the objective lens movable is integrated into the integration section 4.
FEED (feed) via the FEED SW 46 selected and switched to the terminal A side of the low frequency component signal integrated in 3
By driving the feed motor by the driver 7 shown in FIG. 1 using the signal supplied to the amplifying unit 47 and fed and amplified, the servo of the first seek operation for moving the optical head 3 on the target track is performed. In addition, a signal output from the fixed voltage driver 45 that generates a fixed voltage waveform based on a signal corresponding to the moving distance supplied from the system controller 9 is selected and switched to the terminal B side.
FEED (feed) amplifying section 47 via SW 46
The second seek which enables the objective lens of the laser spot and the optical head 3 equipped with the objective lens to be movable by driving the feed motor with the driver 7 shown in FIG. Also performs operation servo.

Further, as shown in FIG. 7, the servo unit 8 converts the tracking error signal TE into an A / D
The tracking servo control is performed by the tracking controller 55 based on the D-converted and A / D-converted signals, and
When the tracking control is off, the reference voltage Vre is calculated from the upper and lower peak values or integrated values of the tracking error signal TE.
An offset value and a gain (amplitude) value for f are measured by the offset gain measuring unit 52. Offset gain correction unit 5 so that each value falls within a predetermined range.
3, the D / A converter 54 outputs the corrected value to the DPD signal generator 26 in FIG. 2 by using OFS D / A as an offset correction value and GAIN as a gain correction value.
D / A is set and output.

FIG. 3 shows a 4.7 GB version ver2.0 of the DVD-R and a version ver2.0 of the DVD-RW.
A tracking error signal (DPD signal) of a DPD in a recorded area and a recordable area (a state recorded in the recordable area is shown in FIG. 3) when reproduced on a disc based on the 1.0 standard ) And the TKC signal.
To be precise, the DPD signal indicates a state where there is no offset in the recordable area and a state where there is an offset in the recorded area. As shown in FIG. 3, for example, in the recorded area of the DVD-RW, the DPD signal is offset with respect to the Vref voltage and slightly different in amplitude from the recordable area. Therefore, the TKC signal obtained by comparing the DPD signal with the reference voltage cannot be obtained accurately in this region as shown in the figure. The reason for this is that in the case of a DVD-RW, the recorded area is manufactured in advance with pre-pits. On the other hand, in the DVD-R disc, the recorded area is recorded by the same method as the normal recording method, so that the offset and the amplitude do not change much. In the switching section, TKC may not be output correctly.

When reproducing a write-once optical disc such as a DVD-RW disc, the first and second lead-in areas are included in the lead-in area on the inner periphery of the data area according to the standard defined at the time of this application. The first lead-in area of the recorded area, which is manufactured in advance with pre-pits, cannot be read, and it is necessary to read physical information such as the disc type from the readable second lead-in area.

On the other hand, when playing back a DVD-R disc, according to the standard, there are first and second lead-in areas in a lead-in area on the inner periphery of a data area. The second lead-in area is readable, and it is necessary to read physical information such as the type of the disc from both lead-in areas.

Here, for example, in a DVD-RW,
Assuming a case where both the first lead-in area and the second lead-in area can be read similarly to the DVD-R, the DPD signal and the TKC signal cannot be obtained accurately as described above. For example, even if the optical head seeks from the position A to the position B in FIG. 4 across the first lead-in area and the second lead-in area, the first pre-pit which is a pre-pit which is a recorded area is used. Since the number of tracks cannot be counted accurately in the lead-in area,
Since the optical head 3 cannot reach the target track position, the seek of the optical head 3 fails, and the lens shift occurs, the focus servo may be deviated.

Therefore, in the optical disk device of the present embodiment, the disk type detecting section 24 is composed of a read-only optical disk (DVD-ROM) and a recording optical disk (DVD-ROM).
R), discriminating at least three types of optical discs for recording (DVD-RW), in other words, by determining whether or not an optical head (laser spot) and an RF signal include a wobbling signal and a difference in reflectance. The three types of discs are discriminated. The disc type detection signal DISCDET thus obtained is judged by the system controller 9, and based on this judgment, the optical head 3
Is performed as an operation adapted to the type of each disk.

That is, the optical disk device according to the embodiment of the present invention comprises a read-only DVD-ROM and a recording DVD-ROM.
In R, seek control is performed on the first lead-in area or the second lead-in area (a position corresponding to or the position corresponding thereto) by an ordinary method, and in the DVD-RW, the state of the first lead-in area is considered. While controlling the seek operation to the second lead-in area, the occurrence of a seek error in the first lead-in area is prevented.

Next, an example of the first seek operation control when the DVD-RW is used in the optical disk device of the present embodiment having the above configuration will be described below with reference to FIG. Note that the first seek operation control is as follows.
This is mainly performed by the system controller 9 in FIG.

First, the system controller 9 controls the servo unit 8 and the driver 7 when the optical disk is loaded in the optical disk device or when the power of the optical disk device in which the optical disk is previously loaded is turned on. To turn on the laser, move the pickup in the focus direction, determine the disc type, and if it is determined to be DVD-RW, set the parameters of the servo system corresponding to the reflectivity of the DVD-RW and set the data. Apply focus control at the position of the area. Next, as described above, the DPD signal is measured, offset and gain are adjusted, and tracking control is performed.

Then, the second lead-in area optical head 3 provided at, for example, the innermost periphery of the optical disk is moved. In this method, two embodiments will be described. This will be described below as a first embodiment and a second embodiment.

In the first embodiment, as shown in FIG. 5A, the system controller 9 controls the FEED S of FIG.
W is switched to the terminal A side, the first seek method is selected,
The optical head 3 is sought to a position D slightly before the first lead-in area known as an address from the position A in FIG.

Next, the FEED SW is switched to the terminal B side, the second seek method is selected, and a predetermined voltage waveform is set so as to exceed the first lead-in area width by the distance obtained by converting the address into a track in advance. Then, the optical head 3 is sought to the first E position in the second lead-in area.

While moving in the first lead-in area, the offset and amplitude of the DPD signal may be measured by the offset and gain adjustment section having the configuration shown in FIG. In the description here, only the measurement will be used, and this measured value will be used later.

Next, the FEED SW is again switched to the terminal A side, the first seek method is selected, and the B position of the target position of the second lead-in area by the number of tracks calculated from the address of the E position in FIG. To seek. With this method, even if there is an offset or gain change in the DPD signal in the first lead-in area, a stable seek is possible because the DPD signal is not used while seeking in this area.

Next, in the second embodiment, as shown in FIG. 5B, the system controller 9 controls the FEED S
W is switched to the terminal A side, the first seek method is selected,
The optical head 3 is sought to a position D slightly before the first lead-in area known as an address from the position A in FIG. 5B. Next, the FEED SW is switched to the terminal B side, the second seek method is selected, a predetermined voltage waveform is applied to the position H in the first lead-in area, and the optical head is moved. The correction values of the state before the offset and the amplitude of the DPD signal are stored, and measured at this position by the offset and gain adjustment unit shown in FIG. 7, and the offset and amplitude correction values are shown in FIG. To the OFS D / A terminal and the GAIN D / A terminal to correct the offset and the gain. Although the DPD signal and the TKC signal at that time are not shown, a signal like the data area in FIG. 5 is obtained.

In this state, the FEED SW is switched to the terminal A side, the first seek method is selected, and H in FIG.
The seek is performed to the target position J in the first lead-in area by the number of tracks calculated from the position address.

Next, the FEED SW is switched to the B side,
The second seek method is selected, and a predetermined voltage waveform is applied to the position of E in the second lead-in area to move. Next, the stored correction value of the state before the offset and amplitude of the DPD signal is output, the FEEDSW is switched to the terminal A side, the first seek method is selected, and the position E in FIG. The optical head 3 is sought to the target position B in the second lead-in area by the number of tracks calculated from the above address. With this method, a stable seek operation can be performed.

Next, three embodiments for reading data in the first lead-in area when a DVD-RW disc is used will be described. This will be described as a third embodiment, a fourth embodiment, and a fifth embodiment.

In the third embodiment, as shown in FIG. 5C, the operation is the same as that of the first embodiment up to the position B of the second lead-in area. DVD-RW at position B
If it is determined that the disc can read the data of the first lead-in area as the lead-in information, the first lead-in area can be read. Seek to E position.

Next, the seek method in the second embodiment is selected, and a predetermined voltage waveform is applied to the position of J in the second lead-in area to move. At this time, the correction value of the state before the offset and the amplitude of the DPD signal is stored, and measured at this position by the offset gain adjustment unit shown in FIG. OFS shown in
Output to the D / A terminal and GAIN D / A terminal for correction. Although the DPD signal and the TKC signal at that time are not shown, a signal like the data area in FIG. 5 is obtained. Then, the FEEDSW is again switched to the terminal A side, the first seek method is selected, and the number of tracks corresponding to the number of tracks calculated from the address of the J position in FIG.
Seek to position. Thereby, the lead-in information at the position C can be read.

Next, in the fourth embodiment, as shown in FIG. 5D, the system controller 9 switches the FEED SW to the terminal A and selects the first seek method.
The seek is performed from the position A in (d) to the position F slightly before the first lead-in area known as an address in advance.
Next, the FEED SW is switched to the terminal B side, the second seek method is selected, and a predetermined voltage waveform is applied to the position of G in the first lead-in area to move. The correction values of the state before the offset and the amplitude of the DPD signal are stored, and measured at this position by the offset and gain adjustment unit shown in FIG. 7, and the offset and amplitude correction values are shown in FIG. O
Output to the FS D / A terminal and the GAIN D / A terminal for correction. Although the DPD signal and the TKC signal at that time are not shown, a signal like the data area in FIG. 5 is obtained. In this state, the FEED SW is switched to the terminal A side, the first seek method is selected, and the C position of the target position of the first lead-in area by the number of tracks calculated from the address of the G position in FIG. Seek the optical head. Thereby, C
The lead-in information at the position can be read.

Next, in the fifth embodiment, when moving from the first lead-in area to the second lead-in area as shown in FIG.
SW is switched to the terminal B side, the second seek method is selected, and a predetermined voltage waveform is applied to the position of J in the second lead-in area to move. A predetermined voltage waveform is applied to the position of G in the first lead-in area to move. The correction values of the state before the offset and the amplitude of the DPD signal are stored, and measured at this position by the offset and gain adjustment unit shown in FIG. 7, and the offset and amplitude correction values are shown in FIG. It is output to the OFS D / A terminal and the GAIN D / A terminal for correction. Next, the FEED SW is switched to the terminal A side, the first seek method is selected, and the number of tracks calculated from the address of the J position in FIG. 5E is shifted to the target position B of the first lead-in area. Seek the optical head. Thereby, the lead-in information at the position B can be read. In this manner, the optical head can be sought freely between the data area, the first lead-in area, and the second lead-in area.

Thus, in the optical disk apparatus of the present embodiment, a stable seek operation can be realized even when a read-only optical disk and a recording optical disk are used together with the same physical specifications. In addition, the occurrence of a miss count due to the delay time as described above can be prevented. In the present embodiment, an example in which both the offset and the amplitude of the DPD signal are corrected has been described as an example.
Either correction may be performed, or both corrections may be switched according to timing.

Further, according to the optical disk apparatus of the present embodiment, as described above, the best seek can be adaptively realized according to the type of the optical disk. That is, according to the optical disc apparatus of the present embodiment, it is possible to perform stable control in the recording area of the optical disc and to perform stable control without generating a seek error such as runaway even when there is a recordable area. Is possible.

Two examples of the second seek operation control in the DVD-R optical disk device of the present embodiment will be described below with reference to FIG. This will be described below as a sixth embodiment and a seventh embodiment.

The second seek operation control is mainly performed by the system controller 9 shown in FIG. Also, this method may be applicable to the case where data in the first lead-in area is read from a DVD-RW disc.

In the sixth embodiment, since the offset and gain change of the DPD signal in the first lead-in area are at a level that does not matter, when seeking to the position B, as shown in FIG. , The system controller 9 is FEED
The switch is switched to the terminal A side, the first seek method is selected, and the seek is directly performed from the position A in FIG. 4A to the position B of the second lead-in area known as an address in advance.

Similarly, in the seventh embodiment, since the offset and gain change of the DPD signal in the first lead-in area are at a level that does not cause any problem, when seeking to the position C, FIG. Like the system controller 9
Switches the FEED SW to the terminal A side, selects the first seek method, and directly seeks from the position A in FIG. 4A to the position C in the first lead-in area known as an address in advance. At this time, if the offset or gain change of the DPD signal becomes a problem when the lead-in information at the position C is reproduced, the offset and / or amplitude of the DPD signal at this position are shown in FIG. And it can be measured and corrected by the gain adjustment unit.

Next, an eighth embodiment will be described. In this embodiment, the DPD signal is similarly generated at the boundary between the first lead-in area and the second lead-in area or the first lead-in area and the data area in FIG. 4 (including FIG. 5). There is a possibility that it is not possible to obtain an accurate result. At this time, the purpose is to prevent the seek from being performed well. If, for example, a recording signal cannot be accurately recorded from the position where the recording should be started at the boundary portion, a mirror area having no recording signal will result. In this case as well, D
No PD signal can be obtained. Also, if the recording signal is sent from a position before the start of recording at the boundary, the amplitude and the like of the DPD signal similarly fluctuate in the overwritten area.

For example, in the case of skipping the first lead-in area on a disc such as a DVD-R,
As shown in FIG. 5 (b) of the embodiment, the first seek method is selected, the seek is performed from the position A to the position D, and in order to jump over the boundary at this position, the second seek is performed as in the above embodiment. Although the seek method may be selected, in the first seek method, a mirror part is detected by detecting the presence or absence of an RF signal from a boundary detection unit that detects this boundary part.
Alternatively, a detection signal is obtained from the address position on the disk), and at this position, a block of the seek control signal 41 is used to skip over this area. A coefficient such as a feedback gain or offset of the generated velocity position feedback signal and a coefficient of the forced acceleration / forced deceleration signal are changed, and the region is jumped to the position H. Next, a coefficient such as a feedback gain or offset of a speed position feedback signal generated from the number signal obtained from the track count 44 and the speed signal when moving from the position A to the position D,
Return to the forced acceleration and deceleration signals and seek from the H position to the J position. The method of seeking from the J position to the E position is D
The method of seeking from the position to the position H is the same as the method of seeking from the position E to the position B, and the method of seeking from the position E to the position B is similar to that of the second embodiment.
A stable seek can be performed even if the D signal is absent or disturbed.

In this case as well, it is possible to seek freely between the data area and the first lead-in area and the second lead-in area. As a result, the optical disc apparatus of the present embodiment can realize a stable seek operation even when the read-only optical disc and the recording optical disc are used together with the same physical specifications. The occurrence of a miscount due to the delay time as described above can be prevented. Further, according to the optical disc device of the present embodiment, as described above, the best seek can be adaptively realized according to the type of the optical disc. That is, according to the optical disc device of the present embodiment, it is possible to perform a stable seek in the recording area of the optical disc, and to perform stable control without generating a seek error such as runaway even when there is a recordable area. It is possible.

As a disk type detection method, in addition to this embodiment, a disk ID written as control information on a disk may be read to determine a difference in physical characteristics due to a difference in disk type or version. Needless to say.

In the above-described embodiment, tracks (lands or grooves) are spirally cut from the inner circumference to the outer circumference used in a single-layer disc such as a DVD, and the inner circumference is used to move from the outer circumference to the outer circumference. Although an optical disk on which recording and reproduction are performed has been described as an example, the present invention is also applicable to an optical disk whose direction is reversed (optical disk on which recording and reproduction are performed from the outer periphery to the inner periphery).

Finally, the description of each of the above embodiments is an example of the present invention, and the present invention is not limited to the above embodiments. For this reason, even in the embodiments other than the above-described embodiments,
It goes without saying that various changes can be made in accordance with the design and the like without departing from the technical idea according to the present invention.

[0080]

As described above, according to the seek control method of the present invention, the read-in recording medium and the recording medium for DVD-R and DVD-RW as the recording medium have different lead-in areas due to differences in versions and the like. Even if disks having different performances are mixedly used (reproduced), a stable seek operation can be realized by adaptively controlling according to the disk type.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating a schematic configuration of an error signal generation section of an amplifier section of the optical disc device according to the embodiment of the present invention.

FIG. 3 is a waveform diagram showing a structure of a disk, and waveforms of a DPD signal and a TKC signal.

FIG. 4 is a diagram used for describing a seek method of the DVD-R optical disc device according to the embodiment of the present invention.

FIG. 5 is a diagram used for describing a seek method of the DVD-RW optical disk device according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram of a seek control block according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram of an offset and gain adjustment block according to the embodiment of this invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk (recording medium only for reproduction, recording medium for recording) 3 ... Optical head 24 ... Disc type detection part (determination means) 25 ... Off-track signal generation part 26 ... DPD signal generation part 27 ... PP or DPP signal generation part 29 ... Track cross signal generation unit 43. Direction detection unit 44. Track count unit (first and second track count means)

Claims (5)

[Claims] 1. A seek control method for moving a head in a direction traversing tracks formed on a recording medium having recordable areas on both sides of a prerecorded area, the method comprising: When seeking the head from an area to a track in the recorded area, or when seeking the head from a first recordable area across the recorded area to a second recordable area, A seek control method comprising: determining a type of a medium; and changing a seek control method of the head according to a result of the type determination of the recording medium. 2. A tracking error detection system of a phase difference method for traversing tracks formed on a recordable recording medium having recordable areas on both sides of a prerecorded area. A seek control method for moving a head from a recordable area to a track of the recorded area, or a second recording method traversing the recorded area from a first recordable area. Changing the seek control method so as to correspond to a change in the offset or amplitude of the tracking error detection signal in the recorded area when the head is sought to a possible area. Method. 3. The seek control method according to claim 1, wherein a head is moved in a direction crossing the track.
And a second seek control method, when seeking from the recordable area to the track of the recorded area, or crossing the recorded area from the first recordable area to the second recording A step of performing a seek by combining the first and second seek control methods according to a result of the type determination of the recording medium when seeking to a possible area. 4. The seek control method according to claim 1, wherein said pre-recorded area is formed by pre-pits in a lead-in area of said recording medium. 5. The seek control method according to claim 4, wherein said recorded area of said lead-in area is formed of pre-pits whose data cannot be reproduced. .