JPH11328690A - Optical disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve stable tracking, focus servo by controlling a movement of a condenser means for condensing light to a disk by means of a tracking signal from which a header part and a part corresponding to a front and a rear parts of the header part are removed. SOLUTION: A tracking control circuit 30 set at a DVD servo seek control unit outputs a tracking signal obtained by removing a header part from a tracking signal generated from a signal from a servo amplifier. A sample/hold circuit 32 turns on a change switch 32a when a header part detection signal from a header part detection circuit 33 is in a low level, thereby digitizing and outputting the tracking signal from a low pass filter 31 to a driver 17. With the use of the header part detection signal, the switch is turned on, off at a part before and after the header part where the tracking signal is stable. The header part detection signal is not output wrong from reproduction data outside the header part as a result of a signal level fluctuation or noises.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a DVD-RAM.
The present invention relates to an optical disk device that performs tracking servo and focus servo on an optical disk such as an optical disk.

[0002]

2. Description of the Related Art Recently, DVD-RAM is used as an optical disk.
Is being developed. In the case of such a DVD-RAM,
The land and the groove are switched every track (alternately) in one round, and the header portion is preformatted in units of a plurality of sectors existing in one track. The plurality of header portions are provided in a staggered manner so as to be shifted in a direction intersecting the track direction.

For example, the content corresponding to a land as a track consisting of four parts, consisting of two parts in the first half and two parts in the latter half, and recorded in the latter two parts, is recorded. The content corresponding to the groove as a track adjacent to the track is recorded.

Conventionally, switching between tracking and focus servo is performed using the detection timing of the header portion. However, when the header detection signal becomes erroneous due to fluctuation of signal level or noise, there is a disadvantage that stable tracking and focus servo cannot be performed due to erroneous servo switching.

[0005]

SUMMARY OF THE INVENTION According to the present invention, when the header detection signal becomes erroneous due to fluctuation of the signal level or noise, erroneous servo switching by the header detection signal causes a stable operation. This eliminates the drawback that accurate tracking and focus servo cannot be performed, and prevents the header detection signal from becoming erroneous due to fluctuations in signal level or noise, and provides stable tracking using this header detection signal. It is another object of the present invention to provide an optical disk device capable of performing focus servo.

[0006]

SUMMARY OF THE INVENTION An optical disk apparatus according to the present invention has a groove and a land recording track for recording spiral or concentric data, and has a header section composed of a fixed length of groove and land and composed of address data. And a data area in which data is recorded. Data is recorded on an optical disc in which the address of the header section is alternately formed for a groove and a land, or In a device for reproducing recorded data, a light collecting means for condensing light on the optical disc, a detecting means for detecting light from the optical disc, and the light condensing means in a direction orthogonal to its optical axis. And a tracking signal for a track on the optical disk based on a detection signal from the detection means. A first output unit that outputs a header detection signal corresponding to before and after including the header and from which signal level fluctuation and noise have been removed, based on the header detection signal from the first output; A second output means for sampling / holding a tracking signal for a track of the optical disc to output a tracking signal from which a portion corresponding to the header portion and its front and rear portions has been removed, and an output by the second output means. Control means for controlling the movement of the light condensing means by the moving means in accordance with the tracking signal.

The optical disk apparatus of the present invention has a groove and a land recording track for recording spiral or concentric data, and has a header and data consisting of a fixed length of groove and land and address data. It has a plurality of recording areas consisting of a data area,
For recording data on an optical disk in which the address of the header section is alternately formed for a groove and a land, or for reproducing data recorded on the optical disk, light is focused on the optical disk. Light collecting means, light detecting means for detecting light from the optical disk, moving means for moving the light collecting means in a direction orthogonal to the optical axis thereof, and optical disk based on a detection signal from the detecting means. A first low-pass filter for removing and delaying a high-frequency signal of a tracking signal for the track;
A second low-pass filter for removing a high-frequency signal of a tracking signal for the track of the optical disk based on the detection signal from the detection means; and a tracking signal for the track of the optical disk based on the signal from the second low-pass filter. A first binarizing circuit for binarizing the data, a first delay circuit for delaying a binarized output from the first binarizing circuit, and a track for the optical disk based on a detection signal from the detecting means. A high-pass filter for removing a low-frequency signal of the tracking signal; a second binarization circuit for binarizing a tracking signal for a track of the optical disk based on a signal from the high-pass filter; and a second binarization circuit Delay circuit for delaying the binarized output from the first delay circuit, the output of the first delay circuit and the output of the second delay circuit And an AND circuit for outputting a logical product,
A sample / hold circuit for sampling / holding an output signal from the first low-pass filter based on an output from the AND circuit; and a movement of the focusing means by the movement means based on an output from the sample / hold circuit. And control means for performing control.

The optical disk apparatus according to the present invention has a groove and a land recording track for recording spiral or concentric data, and has a header and data consisting of a fixed length of groove and land and composed of address data. It has a plurality of recording areas consisting of a data area,
For recording data on an optical disk in which the address of the header section is alternately formed for a groove and a land, or for reproducing data recorded on the optical disk, light is focused on the optical disk. Light collecting means for causing light from the optical disk to be detected, moving means for moving the light collecting means in the optical axis direction, and a focusing signal for the optical disk based on a detection signal from the detecting means. A first output means for outputting a header detection signal corresponding to before and after including the header and removing a signal level fluctuation and noise, and a header detection signal supplied by the first output means. Sampling / holding of the focusing signal for the optical disc based on the detection signal from the detection means except for the period of time With this, the second output means for outputting a focusing signal from which the portion corresponding to the header portion and its front and rear portions are removed, and the focusing means output from the second output means by the moving means for the focusing means And control means for performing movement control.

The optical disk apparatus of the present invention has a groove and a land recording track for recording spiral or concentric data, and a header and data consisting of a fixed length of groove and land and address data are recorded. It has a plurality of recording areas consisting of a data area,
For recording data on an optical disk in which the address of the header section is alternately formed for a groove and a land, or for reproducing data recorded on the optical disk, light is focused on the optical disk. Focusing means for causing the light from the optical disc to be detected, a moving means for moving the focusing means in the optical axis direction, and a focusing signal of the optical disc based on a detection signal from the detecting means. A first low-pass filter that removes and delays a high-frequency signal, a second low-pass filter that removes a high-frequency signal of the focusing signal of the optical disk based on the detection signal from the detection unit, and a second low-pass filter. A first binarizing circuit for binarizing a focusing signal of the optical disk based on the signal of
A first delaying the binarized output from the first binarizing circuit;
A high-pass filter for removing a low-frequency signal of the focusing signal of the optical disk based on the detection signal from the detection means, and a second signal for binarizing the focusing signal of the optical disk based on the signal from the high-pass filter. , A second delay circuit for delaying the binary output from the second binary circuit, and the logical product of the output of the first delay circuit and the output of the second delay circuit Circuit, a sample / hold circuit for sampling / holding the output signal from the first low-pass filter based on the output from the AND circuit, and the moving means based on the output from the sample / hold circuit. And control means for controlling the movement of the light condensing means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical disk device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an optical disk device. This optical disc device is for recording data on an optical disc (DVD-RAM) 1 and reproducing data from the optical disc 1.

This optical disk device is configured as a device capable of reading data not only from a DVD-RAM but also from other DVD disks and CD disks, and writing data to a rewritable DVD disk. .

Therefore, the optical pick-up 2 has a DV
It has an objective lens 3 for D and an objective lens 4 for CD. In the optical pickup 2, semiconductor laser units (not shown) for DVD and CD are provided corresponding to the objective lens 3 for DVD and the objective lens 4 for CD. Is a DVD disc or C
One of the semiconductor laser units is selected according to whether it is a D disk, and is activated by the laser control unit 5 to generate a laser beam of a corresponding wavelength. When one of the semiconductor laser units for DVD and CD is selected and energized, the laser beam corresponding to the optical disk 1 is directed to the corresponding objective lens 3, 4. The light is converged on the optical disc 1. Data is written to or reproduced from the optical disk 1 by the converged laser beam.

The setting of the laser control unit 5 is set by the DVD data processing unit 6. The setting includes a reproduction mode for obtaining a reproduction signal, a recording mode for recording data, an erasing mode for erasing data, and a DV mode.
The DVD mode for executing data processing on the D disk and the CD mode for executing data processing on the CD disk are different. That is, in the DVD mode, the DVD
The semiconductor laser unit for CD is selected and energized, and in the CD mode, the semiconductor laser unit for CD is selected and energized. The laser beam for DVD or CD has different levels of power in three modes of a reproducing mode, a recording mode, and an erasing mode, and a semiconductor laser is generated so that a laser beam having a power corresponding to the mode is generated. The unit is energized by the laser control unit 5;

The DVD disk or the CD is arranged so that the DVD disk 1 or the CD disk is arranged to face the DVD objective lens 3 and the CD objective lens 4.
The disk is transported into the apparatus by the tray 7 directly or stored in the disk cartridge 1a. A tray motor 8 for driving the tray 7 is provided in the apparatus. The loaded DVD disk 1 or CD disk is rotatably held on a spindle motor 10 by a stamper 9 and rotated by the spindle motor 10. The optical pick-up 2 is a feed mechanism (not shown) driven by a feed motor 11
The optical disc 1 is placed on the optical disc 1 and moved in the radial direction of the optical disc 1 by the feed mechanism.

The optical pickup 2 has a photodetector (not shown) for detecting a laser beam therein. This photodetector is reflected by the optical disc 1 and the objective lens 3,
4 to detect the laser beam returned. A detection signal (current signal) from the photodetector is converted into a voltage signal by a current / voltage converter (I / V) 12, and this signal is
It is supplied to the reference amplifier 13 and the servo amplifier 14. A reproduction signal as an addition signal is output from the reference amplifier 13 to the DVD data processing unit 6. The servo signal from the servo amplifier 14 is DV
In the D mode, the DVD servo seek control unit 15
In the CD mode, the data is output to the CD servo seek control and CD data processing unit 16.

As a method for optically detecting the amount of defocus, there is, for example, the following method. [Astigmatism Method] An optical element (not shown) for generating astigmatism is arranged on a detection optical path of laser light reflected by a light reflection film or a light reflection recording film of the optical disc 1, and is placed on a photodetector. This is a method for detecting a change in the shape of the irradiated laser light. The light detection area is divided into four diagonally. The difference between the diagonal sums of the detection signals obtained from the respective detection areas is calculated in the DVD servo seek control unit 15 to obtain a focus error detection signal (focus signal).

[Knife Edge Method] This is a method of arranging a knife edge that asymmetrically shields a part of the laser light reflected by the optical disc 1. The light detection area is divided into two parts, and a difference between detection signals obtained from each detection area is obtained to obtain a focus error detection signal.

Usually, either the astigmatism method or the knife edge method is employed. The optical disc 1 has spiral or concentric tracks, and information is recorded on the tracks. Information is reproduced or recorded / erased by tracing the converged spot along this track.
In order to stably trace the focused spot along the track, it is necessary to optically detect the relative displacement between the track and the focused spot.

Generally, the following method is used as a track shift detecting method. [Phase difference detection (Differential
Phase Detection) Method] A change in the intensity distribution of the laser light reflected by the light reflection film or the light reflection recording film of the optical disk 201 on the photodetector is detected. The light detection area is divided into four on a diagonal line. The difference between the diagonal sums of the detection signals obtained from the respective detection areas is calculated in the DVD servo seek control unit 15 to obtain a track error detection signal (tracking signal).

[Push-Pull Method] A change in the intensity distribution of the laser beam reflected by the optical disk 1 on the photodetector is detected. The light detection area is divided into two parts, and a track error detection signal is obtained by taking the difference between the detection signals obtained from each detection area.

[Twin-Spot Method] A diffractive element or the like is arranged in a light transmission system between the semiconductor laser element and the optical disk 1 to split the light into a plurality of wavefronts and to irradiate the optical disk 1 with ± first-order diffracted light. The change in reflected light amount is detected. A light detection area for individually detecting the reflected light amount of the + 1st-order diffracted light and the reflected light amount of the -1st-order diffracted light is arranged separately from the light detection area for detecting the reproduction signal. Get.

In the DVD mode, a focus signal, a tracking signal, and a feed signal are sent from the DVD servo seek control unit 15 to a focus and tracking actuator driver and a feed motor driver 17, and the objective lenses 3, 4 are driven by the driver 17. Focus servo control and tracking servo control are performed. Further, the driver 1 responds to the access signal.
7 is supplied to the feed motor 11 from the optical pickup.
Up 2 is transported. The DVD servo seek control unit 15 is controlled by the DVD data processing unit 6. For example, the DVD data processing unit 6
Supplies an access signal to the DVD servo seek control unit 15 to generate a feed signal. DVD
The spindle motor driver 18 and the tray motor driver 19 are controlled by a control signal from the data processing unit 6.
Is controlled, the spindle motor 10 and the tray motor 8 are energized, the spindle motor 10 is rotated at a predetermined rotation speed, and the tray motor 8 appropriately controls the tray. The reproduction signal supplied to the DVD data processing unit 6 stores necessary data in the RAM 20, and the reproduction signal is processed by the DVD data processing unit 6, and the SCSI interface control unit having the RAM 21 as a buffer and the CD-ROM decoder 22 and other devices via SCSI, such as personal
A reproduction processing signal is supplied to the computer.

In the CD mode, a focus signal, a tracking signal, and a feed signal are sent from a CD servo seek control and CD data processing unit 16 to a focus and tracking actuator driver and a feed motor driver 17, and the driver 17 outputs an objective lens. 3 and 4 are focus servo controlled, and
Tracking servo control. Further, an urging signal is supplied from the driver 17 to the feed motor 11 in response to the access signal, and the transport of the optical pickup 2 is controlled. This C
D servo seek control and CD data processing unit 1
Spindle motor driver 18 by control signal from 6
Then, the tray motor driver 19 is controlled, the spindle motor 10 is energized, and the spindle motor 10 is rotated at a predetermined rotation speed. The reproduction signal supplied to the CD data processing unit 16 is processed by the processing unit 16 and output through the CD data output amplifier 23.

Each unit shown in FIG. 1 is controlled by the CPU 25 in accordance with the procedure stored in the ROM 24. RA
M26 is used as a memory of the CPU 25. next,
The structure of the DVD-RAM optical disk 1 created above will be described.

The optical disk 1 has a thickness of, for example, 0.6 m.
m, a disc-shaped substrate made of a transparent resin such as polycarbonate or acrylic, a phase-change recording film, a reflective film, a protective film, and a sheet or adhesive for bonding. Grooves and header information are recorded in an irregular shape on a transparent substrate, a recording film or the like is formed on the irregular surface, and then the irregular surfaces are adhered to each other so that recording and reproduction can be performed on both surfaces.

As shown in FIGS. 2 and 3, the optical disk 1 is composed of a header portion 51 composed of a pre-tracked wobbled groove and a pre-pit (emboss pit) row indicating a track address and the like.

That is, the tracking groove is wobbled at a constant cycle in order to obtain a reference signal for data recording. At this time, the phase of the signal for wobbling the header section 51 and the tracking groove at a constant period is made to substantially match.

The header section 51 first wobbles outward, then wobbles inward, and the wobbles of the tracking groove also wobbles outward, and then wobbles inward.

As shown in FIGS. 4 and 5, the optical disc 1 has a data zone 46 which can be rewritten with the emboss data zone 45 of the lead-in area 42, a zone 43a of the data area 43,... The readout area 44 includes data zones. The clock signal for each zone is the same, and the rotation speed (speed) of the optical disc 1 and the number of sectors for each track are different for each zone.

A plurality of (189) lead-in areas 42 are provided.
6) An emboss data zone 45 composed of tracks and a rewritable data zone 46 composed of a plurality of tracks. The emboss data zone 45 includes a blank zone, a reference signal zone, a blank zone, a control data zone, and a blank zone. In the emboss data zone 45, reference signals and control data are recorded at the time of manufacturing. The rewritable data zone 46 includes a guard track zone, a disk test zone, a drive test zone, a disk identification data zone, and a replacement management zone as a replacement management area.

The data area 43 has a plurality (1) in the radial direction.
888), for example, 24 zones 43a,... 43x. However, only the zone 43a has 1888 tracks including the rewritable data zone 46.

The lead-out area 44 includes a plurality (144
6) The track is a rewritable data zone similar to the rewritable data zone 46, and can record the same contents as the data zone 46.

The zones 43a,... 43 of the data area 43
In x, the number of rotations (speed 39.78 to 16.91H
z) becomes slow, and the number of sectors per track (17 to 4)
0) increases.

The zones 43a of the data area 43,...
As shown in FIGS. 4 and 5, the 43x track has an ECC (error correction cod) as a data recording unit.
e) Block data unit (for example, 38688 bytes)
Each time, data is recorded.

The ECC block is composed of 16 sectors in which 2K bytes of data are recorded. For each sector, two 4-byte (32-bit) sector IDs (identification data) 1 to ID 16 as address data are 2 bytes. A horizontal ECC (error) is added to main data (sector data) together with an error detection code (IED: ID error detection code) of the configuration and serves as an error correction code for reproducing data recorded in an ECC block.
correction code) 1 and ECC2 in the vertical direction are recorded. These ECCs 1 and 2 are
The error correction code is added to the data as a redundant word in order to prevent the data from being unable to be reproduced due to the defect of the data.

Each sector is composed of 172 bytes of 12 rows of data. Each row (line) is provided with a 10-byte horizontal ECC1 and 18 rows.
A vertical ECC2 for one row of a 2-byte configuration is provided. Thus, the error correction circuit 92 described later performs error correction processing for each line using the horizontal ECC 1 and performs error correction processing for each column using the vertical ECC 2. .

When the ECC block is recorded on the optical disc 1, byte synchronization is performed when data is reproduced for each predetermined data amount of each sector (for each predetermined data length interval, for example, 91 bytes: 1456 channel bits). Synchronization code to take (2 bytes: 32 channel bits)
Is given.

Each sector is composed of 26 frames from the 0th frame to the 25th frame, and the synchronization code (frame synchronization signal) given to each frame is:
A specific code (1 byte:
16 bits) and a common code (1 byte: 16 channel bits) common to each frame.

The zones 43a of the data area 43,...
As shown in FIGS. 3 and 4, headers 51,... In which addresses and the like are recorded for each sector are pre-formatted on the 43x track in advance.

The header section 51 is formed when the groove is formed. This header section 51
Is composed of a plurality of header areas 52 composed of a plurality of pits, as shown in FIGS.
3 is preformatted as shown in the figure, and the center of the pit is located on the same line as the center of the amplitude of the boundary line between the groove 53 and the land 54. FIG. 6 shows a header section 51 added to the first sector of each track, and FIG. 7 shows a header section 51 added to a sector in the middle of each track.

In this case, the header portion for the groove and the header portion for the land are formed alternately (in a staggered manner). The format for each sector is shown in FIG.

In FIG. 8, one sector is composed of 2697 bytes (bytes), a 128-byte header area (corresponding to the header section 51) 51, a 2-byte mirror area 57,
It is composed of a recording area 58 of 2567 bytes.

The channel bits recorded in the sector have a format in which 8-bit data is modulated into 16-bit channel bits by 8-16 code. The header area 51 is an area where predetermined data is recorded when the optical disc 1 is manufactured. This header area 51
It is composed of four header 1 areas, two header areas, three header areas, and four header areas.

The header 1 area to the header 4 area are composed of 46 bytes or 18 bytes, and a 36-byte or 8-byte synchronization code part VFO (Variable Frequency O).
scillator), 3-byte address mark AM (Addres
s Mark), 4-byte address part PID (Position Ide)
ntifier), 2-byte error detection code IED (ID Err
or Detection Code) 1 byte postamble PA
(Postambles).

The header 1 area and the header 3 area have a 36-byte synchronization code section VFO1, and the header area 2 and the header 4 area have an 8-byte synchronization code section VFO2.

The synchronization code portions VFO1 and VFO2 are areas for pulling in the PLL. The synchronization code portion VFO1 records a sequence of "010 ..." in channel bits for "36" bytes (576 bits in channel bits) ( (Recording a pattern at a fixed interval), and the synchronization code portion VFO
Reference numeral 2 denotes a sequence of “010...” Of channel bits recorded for “8” bytes (128 bits of channel bits).

The address mark AM is a "3" byte synchronization code indicating where the sector address starts. As a pattern of each byte of the address mark AM, a special pattern which does not appear in the data portion of "0100100000000100" is used.

Address sections PID1 to PID4 are sector addresses (including ID numbers) as 4-byte address information.
Is an area where is recorded. The sector address is a physical sector number as a physical address indicating a physical position on the track. Since this physical sector number is recorded in the mastering step, it cannot be rewritten.

The ID number is, for example, “1” in the case of PID1, and is a number representing the number of the four times overwriting in one header section 51. Error detection code IED
Is an error (error) detection code for a sector address (including an ID number), and can detect the presence or absence of an error in the read PID.

The postamble PA includes state information necessary for demodulation, and also has a role of adjusting the polarity so that the header section 51 ends with a space. The mirror area 57 is used for offset correction of a tracking error signal, timing generation of a land / groove switching signal, and the like.

The recording area 58 has a gap area of 10 to 26 bytes, a guard 1 area of 20 to 26 bytes, and a V area of 35 bytes.
FO3 area, 3-byte pre-synchronous code (P
S) area, data area of 2418 bytes, postamble 3 (PA3) area of 1 byte, guard 2 area of 48 to 55 bytes, and buffer area of 9 to 25 bytes.

The recording area 58 is composed of a non-wobble area 58a provided at the head and an area wobbled with a predetermined wobble amplitude based on a predetermined frequency provided subsequent to this area. .

The gap area is an area where nothing is written. The guard 1 area is an area provided in order to prevent terminal deterioration at the time of repetitive recording peculiar to the phase change recording medium from reaching the VFO3 area.

The VFO3 area is also an area for PLL lock, but is also an area for inserting a synchronization code in the same pattern to synchronize byte boundaries. PS
The (pre-synchronous code) area is a tuning area for connecting to a data area.

The data area includes a data ID and a data ID error correction code IED (Data ID Error Detection Code).
e), synchronization code, ECC (Error Correction Code)
), An EDC (Error Detection Code), user data, and the like. The data ID is a sector ID 1 of 4 bytes (32 channel bits) of each sector.
~ ID16. Data ID error correction code IED
Is a 2-byte (16-bit) error correction code for data ID.

The sector IDs (1 to 16) are composed of 1-byte (8-bit) sector information and 3-byte sector numbers (logical sector numbers as logical addresses indicating logical positions on tracks). ing. The sector information includes a 1-bit sector format type area,
It is composed of a bit tracking method area, a 1-bit reflectivity area, a 1-bit reserved area, a 2-bit area type area, a 1-bit data type area, and a 1-bit layer number area.

The logical sector number becomes different from the physical sector number due to the slip replacement process due to the initial defect. The PA (postamble) 3 area contains state information necessary for demodulation and is an area indicating the end of the last byte of the previous data area.

The guard 2 area is an area provided for preventing the end deterioration at the time of repetitive recording peculiar to the phase change recording medium from reaching the data area. The buffer area is an area provided for absorbing rotation fluctuation of a motor for rotating the optical disc 1 so that the data area does not cover the next header section 51.

The reason why the gap area is expressed as 10 + J / 16 bytes is that a random shift is performed. The random shift is to shift the data write start position in order to reduce the repetitive recording deterioration of the phase change recording medium. The length of the random shift is adjusted by the length of the buffer area located at the end of the data area, and the entire length of one sector is fixed at 2697 bytes.

The zones 43a of the data area 43,...
As described above, spare sectors are prepared in the 43x, and are used as final spares when a sector-based slip replacement process (slipping replacement algorithm) is performed in the same zone. .

Next, a tracking control circuit 30 as shown in FIG. 9 is provided in the DVD servo seek control unit 15. The tracking control circuit 3
Numeral 0 outputs a tracking signal obtained by removing a portion corresponding to the header section 51 from a tracking signal (tracking error signal) generated by a signal from the servo amplifier 14.

As shown in FIG. 9, the tracking control circuit 30 includes a low-pass filter 31, a sample / hold circuit 32, and a header detection circuit 33.

The low-pass filter 31 includes a capacitor C1
The sample / hold circuit 32 includes a changeover switch 32a, a capacitor C2, a resistor R2, and an A / D converter 32b. The header detection circuit 33 includes a low-pass filter 41 and a high-pass filter 42. , Resistors R3, R4, R5,
R6, R7, R8, R9, R10, comparator 43
a, 43b, 43c, 43d, monomultivibrators 44a, 44b, 44c, 44d, OR circuits 45, 4
6, and AND circuits 47 and 48.

The low-pass filter 41, high-pass filter 42, resistors R3, R4, R5, R6, R7, R8,
R9, R10, comparators 43a, 43b, 43c,
A window comparator is constituted by 43d, and a delay circuit 34 is constituted by monomultivibrators 44a, 44b, 44c and 44d.

The low-pass filter 31 is provided as shown in FIG.
And outputs a delayed signal by removing harmonics from the tracking signal. Low-pass filter 31
The delay of the signal in the header portion in the tracking signal caused by this causes the sample / hold switching position to be brought before the front end of the header portion.

The low-pass filter 41 is shown in FIG.
A signal as shown in FIG. 11D in which high-frequency components are removed from the tracking signal as shown in FIG. The high-pass filter 42 outputs a signal obtained by removing a low-frequency component from the tracking signal, that is, a signal fluctuation or a gentle fluctuation due to noise.

The comparators 43a, 43b, 43c, 4
The reference voltage 3d is changed by the low-pass filter 41 in accordance with the drift of the tracking signal and the gradual fluctuation due to noise.

The mono-multi vibrator 44a is provided in FIG.
(A), (b) of FIG. 11 and (b) of FIG. 11 in which the binarized output binarized by the comparator 43a at the plus side slice level from the tracking signal as shown in (a) of FIG. 12 is delayed. ) Is output.

The mono-multi vibrator 44b has the configuration shown in FIG.
11A and FIG. 11C in which the binarized output binarized by the comparator 43b at the minus slice level from the tracking signal shown in FIG. ) Is output.

The mono-multi vibrator 44c has the configuration shown in FIG.
(E) and a signal obtained by delaying the binarized output binarized by the comparator 43c at the plus slice level from the tracking signal as shown in (d) of FIG.

The mono-multi vibrator 44d is provided as shown in FIG.
(E) and a signal obtained by delaying a binarized output binarized by the comparator 43d at the negative slice level from the tracking signal as shown in (d) of FIG.

The OR circuit 45 takes the logical sum of the outputs of the monomultivibrators 44c and 44d, and outputs signals as shown in FIGS. 11 (f) and 12 (e). That is, a mask signal for the header section 51 is output.

The AND circuit 47 outputs a header part detection signal for a part corresponding to the first half of the header part 51 in the tracking signal by taking the AND of the output of the monomultivibrator 44a and the OR circuit 45. .

The AND circuit 48 outputs a header part detection signal for a part corresponding to the latter half of the header part 51 in the tracking signal by ANDing the output of the monomultivibrator 44b and the OR circuit 45. .

The OR circuit 46 outputs a header detection signal for the entire header 51 as shown in FIG. 11F by taking the logical sum of the outputs of the AND circuits 47 and 48. .

In the sample / hold circuit 32, when the header detection signal from the OR circuit 46 in the header detection circuit 30 is at a high level, the changeover switch 32a is off, and the tracking signal from the low-pass filter 31 is When the signal is cut off and the header detection signal from the AND circuit 35 is at the low level, the changeover switch 32a is turned on, and the tracking signal from the low-pass filter 31 is supplied to the A / D converter 32b. A digital value tracking signal is output to the driver 17 from 32b.

Next, the tracking operation in the above configuration will be described. For example, when tracking a predetermined track (groove or land), the DVD servo seek control unit 15 generates a tracking signal as shown in FIG. Low-pass filter 31 in control circuit 30, header detection circuit 33
Are supplied to a low-pass filter 41, a high-pass filter 42, and comparators 43a and 43b.

As a result, a signal obtained by removing the higher harmonics of the header portion output from the low-pass filter 31 and delaying the same is supplied to the sample / hold circuit 32. Also,
In the header detection circuit 33, a binary value is generated at a slice level on the plus side (generated using a signal obtained by removing a high-frequency component from the tracking signal by the low-pass filter 41) from the tracking signal as shown in FIG. The binarized output is output from the comparator 43a and supplied to the mono multivibrator 44a.

Further, in the header detection circuit 33, FIG.
A comparator 4 converts a binarized output from the tracking signal as shown in (a) into a negative slice level (generated by using a signal obtained by removing a high-frequency component from the tracking signal by the low-pass filter 41).
3b and supplied to the mono multivibrator 44b.

Thus, the mono-multi vibrator 44
a outputs a delayed output shown in FIG. 11B to the AND circuit 47 by delaying the rear end of the high level of the binary output from the comparator 43a to the AND circuit 47;
b outputs to the AND circuit 48 a delayed output shown in (c) of FIG. 11 in which the rear end of the high level of the binary output from the comparator 43b is delayed.

Further, in the header detecting circuit 33, FIG.
A comparator binarizes the binarized output from the high-pass filter 42 with a slice level on the plus side (generated by using the low-pass filter 41 by removing a high-frequency component from the tracking signal) as shown in FIG. 43c and supplies it to the mono multivibrator 44c.

Further, in the header detecting circuit 33, FIG.
(E) shows a comparator which binarizes the binarized output from the high-pass filter 42 at the negative slice level (generated by using the low-pass filter 41 using a signal obtained by removing a high-frequency component from the tracking signal). The output from 43d is supplied to the mono-multi vibrator 44d.

Thus, the mono-multi vibrator 44
c outputs a delayed output to the AND circuit 47 via the OR circuit 45 by delaying the rear end of the high level of the binary output from the comparator 43c.
b outputs a delayed output to the AND circuit 48 via the OR circuit 45 with a delayed high-level rear end of the binary output from the comparator 43b.

As a result, the logical sum of the outputs of the AND circuits 47 and 48 is obtained by the OR circuit 46, and this output includes the header shown in FIG. Part detection signal,
Output to the sample / hold circuit 32.

That is, the rising portion of the header detection signal shown in FIG. 11F is sufficiently before the leading portion of the header of the tracking signal from the low-pass filter 31, and FIG. The falling portion of the header detection signal shown is sufficiently later than the trailing end of the header of the tracking signal from the low-pass filter 31.

In addition to the header 51, as shown in FIG. 12A, the recording data causes the tracking signal to exceed the slice level, and the mono multivibrators 44a and 44b move from the monomultivibrators 44a and 44b to FIG. c)
Is output, the outputs of the mono-multivibrators 44c and 44d, that is, the outputs of the OR circuits are at the low level, the outputs of the AND circuits 47 and 48 remain at the low level, and the header detection signal is output. Is not output.

Therefore, the sample / hold circuit 32
Performs the sample / hold by masking the tracking signal from the low-pass filter 31 with the supplied header detection signal.
It is converted into a digital value by the / D converter 32b and output to the driver 17.

As described above, in the case of the DVD-RAM optical disk 1, the header portion shifted in the inner and outer circumferential directions by approximately 1/2 track with respect to the tracking groove or land is previously recorded on the optical disk 1. It is recorded in pre-pits (concavities and convexities).
As shown in (a), the tracking signal is embedded in the header signal. At this time, as a signal for detecting the header portion, the detection when approaching the header portion is performed at a high speed, and the detection of the completion of the header portion is detected by adding a sufficient time delay. is there.

Using this header detection signal, the sample / hold for the tracking signal can be switched on and off when the tracking signal before and after the header is stable.

That is, it is detected that a header section has been reached, and when the tracking signal is sampled / held, a hold switch is performed before the header section of the tracking signal, and the sample mode is set when a sufficient time has elapsed for shifting to the header section. It is designed to be switched.

As a result, the sample / hold operation can be performed at a stable point with respect to the tracking servo, and stable tracking can be performed even when the header portion exists.

Further, it is possible to prevent a header detection signal from being output erroneously due to reproduced data in portions other than the header portion due to fluctuations in signal level and noise, and to perform stable tracking servo using the header portion detection signal.

In the above embodiment, the case where the signal of the header section is removed from the tracking signal has been described. However, the case where the signal of the header section is removed from the focusing signal can be similarly carried out with reference to FIGS. .

Therefore, the sample / hold for the focusing signal can be switched on and off when the focusing signal before and after the header is stable using the header detection signal.

As a result, the sample / hold operation can be performed at a stable point with respect to the focusing servo, and stable focusing can be performed even when the header portion exists. At this time, it is possible to remove the influence of crosstalk and the like in the header portion.

Further, it is possible to prevent a header detection signal from being output erroneously due to reproduced data in a portion other than the header portion due to a fluctuation in signal level or noise, and it is possible to perform a stable focus servo using the header portion detection signal.

In each of the above embodiments, the sample / hold circuit is used. However, the present invention is not limited to this, and the gain may be switched, and the same can be implemented as long as the reference is fixed.

[0098]

As described in detail above, according to the present invention, the header detection signal can be prevented from being erroneous due to fluctuations in signal level or noise, and can be stabilized by using this header detection signal. An optical disk device capable of performing accurate tracking and focus servo can be provided.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a schematic configuration of an optical disc.

FIG. 3 is a diagram showing a wobble situation of a header portion and a groove portion of the optical disc.

FIG. 4 is a plan view showing a schematic configuration of an optical disc.

FIG. 5 is a plan view showing a schematic configuration of an optical disc.

FIG. 6 is a view for explaining the state of preformat data in a header portion of an optical disc, and surrounding grooves and lands.

FIG. 7 is a view for explaining the state of preformat data in a header portion of an optical disc and peripheral grooves and lands.

FIG. 8 is a diagram showing a sector format for each sector.

FIG. 9 is a circuit diagram showing a schematic configuration of a tracking control circuit.

FIG. 10 is a circuit diagram showing a schematic configuration of a header detection circuit.

FIG. 11 is a signal waveform diagram of a main part in the tracking control circuit.

FIG. 12 is a signal waveform diagram of a main part in the tracking control circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... Optical pick-up 3 ... Objective lens 14 ... Servo amplifier 15 ... DVD servo seek control unit 17 ... Driver 30 ... Tracking control circuit 31, 41 ... Low-pass filter 32 ... Sample / hold circuit 33 ... Header part Detector circuit 42 High-pass filter 43a, comparator 44a, monomultivibrator 45, 46 OR circuit 47, 48 AND circuit

Claims (6)

[Claims] The present invention has a groove and land recording track for recording spiral or concentric data, and comprises a header section composed of a fixed length of groove and land and composed of address data, and a data area in which data is recorded. An optical disc device that has a plurality of recording areas and records data on an optical disc in which the address of the header section is alternately formed for grooves and lands, or reproduces data recorded on the optical disc. Condensing means for condensing light on the optical disc; detecting means for detecting light from the optical disc; moving means for moving the condensing means in a direction orthogonal to the optical axis; Using the tracking signal for the track of the optical disc based on the detection signal from First output means for outputting a header detection signal responsive to the signal level and from which signal level fluctuations and noise have been removed, and a tracking signal for a track on the optical disk based on the header detection signal from the first output means. And a second output means for outputting a tracking signal from which a portion corresponding to the header part and the part before and after the header part have been removed, and a tracking signal output by the second output means, An optical disc device comprising: a control unit that controls the movement of the light condensing unit. 2. It has a groove and a land recording track for recording spiral or concentric data, and comprises a header section composed of a fixed length of groove and land and composed of address data, and a data area in which data is recorded. An optical disc device that has a plurality of recording areas and records data on an optical disc in which the address of the header section is alternately formed for grooves and lands, or reproduces data recorded on the optical disc. Condensing means for condensing light on the optical disc; detecting means for detecting light from the optical disc; moving means for moving the condensing means in a direction orthogonal to the optical axis; A first method for removing and delaying a high-frequency signal of a tracking signal for a track of the optical disk based on a detection signal from the optical disk. A pass filter; a second low-pass filter for removing a high-frequency signal of a tracking signal for a track of the optical disk based on a detection signal from the detection means; and a second low-pass filter for removing a track of the optical disk based on a signal from the second low-pass filter. A first binarizing circuit for binarizing the tracking signal; and a first for delaying a binarized output from the first binarizing circuit.
A high-pass filter for removing a low-frequency signal of a tracking signal for the track of the optical disk based on the detection signal from the detection means; and a binary tracking signal for the track of the optical disk based on the signal from the high-pass filter. A second binarizing circuit for converting a binary output from the second binarizing circuit
And an AND circuit that outputs the logical product of the output of the first delay circuit and the output of the second delay circuit. The output from the first low-pass filter based on the output from the AND circuit An optical disc device comprising: a sample / hold circuit for sampling / holding a signal; and control means for controlling the movement of the condensing means by the moving means based on an output from the sample / hold circuit. 3. It has a groove and land recording track for recording spiral or concentric data, and comprises a header section composed of grooves and lands of a fixed length and composed of address data, and a data area in which data is recorded. An optical disc device that has a plurality of recording areas and records data on an optical disc in which the address of the header section is alternately formed for grooves and lands, or reproduces data recorded on the optical disc. Condensing means for condensing light on the optical disc; detecting means for detecting light from the optical disc; moving means for moving the condensing means in the direction of the optical axis; detection from the detecting means Using the focusing signal for the optical disk based on the signal, the signal level corresponding to before and after including the header part is obtained. A first output unit that outputs a header detection signal from which the header and the noise have been removed, and a detection signal from the detection unit except for a period in which the header detection signal is supplied by the first output unit. Second output means for sampling / holding a focusing signal for the optical disc based on the above, thereby outputting a focusing signal in which a portion corresponding to the header portion and its front and rear portions has been removed, and focusing output by the second output means. An optical disk device, comprising: a control unit that controls the movement of the condensing unit by the moving unit by a signal. 4. It has a groove and land recording track for recording spiral or concentric data, and comprises a header section composed of a fixed length of groove and land and composed of address data, and a data area in which data is recorded. An optical disc device that has a plurality of recording areas and records data on an optical disc in which the address of the header section is alternately formed for grooves and lands, or reproduces data recorded on the optical disc. Condensing means for condensing light on the optical disc; detecting means for detecting light from the optical disc; moving means for moving the condensing means in the direction of the optical axis; detection from the detecting means A first low-pass filter for removing and delaying a high-frequency signal of the focusing signal of the optical disk based on the signal; A second low-pass filter for removing a high-frequency signal of the focusing signal of the optical disk based on the detection signal from the means; and a first low-pass filter for binarizing the focusing signal of the optical disk based on the signal from the second low-pass filter. A binarizing circuit, and a first for delaying a binarized output from the first binarizing circuit
A high-pass filter for removing a low-frequency signal of the focusing signal of the optical disk based on the detection signal from the detection means, and a second signal for binarizing the focusing signal of the optical disk based on the signal from the high-pass filter. A second binarizing circuit for delaying a binarized output from the second binarizing circuit.
And an AND circuit that outputs the logical product of the output of the first delay circuit and the output of the second delay circuit. The output from the first low-pass filter based on the output from the AND circuit An optical disc device comprising: a sample / hold circuit for sampling / holding a signal; and control means for controlling the movement of the condensing means by the moving means based on an output from the sample / hold circuit. 5. It has a groove and land recording track for recording spiral or concentric data, and comprises a header section composed of grooves and lands of a fixed length and composed of address data, and a data area on which data is recorded. In the case of recording data on an optical disk having a plurality of recording areas and the addresses of the header portion being alternately formed for grooves and lands, or for reproducing data recorded on the optical disk, The light is condensed on the optical disk by the light condensing means, and the light from the optical disk is detected by the light condensing. Outputs a header detection signal that is compatible and removes signal level fluctuation and noise. Except for the period in which the header part detection signal is supplied, the tracking signal for the track of the optical disk based on the detection signal is sampled / held, whereby the tracking signal obtained by removing the part corresponding to the header part and the part before and after the header part is removed. Outputting the tracking signal, and controlling the movement of the light condensing means in a direction orthogonal to the optical axis by the output tracking signal. 6. It has a groove and a land recording track for recording spiral or concentric data, and comprises a header section composed of grooves and lands of a fixed length and composed of address data, and a data area in which data is recorded. In the case of recording data on an optical disk having a plurality of recording areas and the addresses of the header portion being alternately formed for grooves and lands, or for reproducing data recorded on the optical disk, The light is condensed on the optical disc by a light condensing means, and the light from the optical disc is detected by the condensing. Using a focusing signal for the track of the optical disc based on the detection signal, before and after including the header portion, Outputs a header detection signal that is compatible and removes signal level fluctuations and noise. Excluding the period in which the header part detection signal is supplied, by sampling / holding a focusing signal for the optical disk based on the detection signal, outputting a focusing signal in which a portion corresponding to the header part and its front and rear parts has been removed, Controlling the movement of the condensing means in a direction orthogonal to the optical axis thereof by the output focusing signal.