JP3875399B2 - Tracking method for optical disk device and tracking method for DVD-RAM drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention has grooves and lands for recording spiral or concentric data, and includes a plurality of recording areas including a header portion made of address data and a data area in which data is recorded. Data is recorded on an optical disc such as a DVD-RAM disc having the above, or data recorded on an optical disc such as a DVD-RAM disc is reproduced, and the address of the header portion is alternately used for a groove and a land. The present invention relates to a tracking method for a formed optical disk device and a tracking method for a DVD-RAM drive device .
[0002]
[Prior art]
In recent years, it has grooves and lands for recording spiral or concentric data, and has a plurality of recording areas consisting of a header part made up of address data and a data area where data is recorded, made up of grooves and lands of a fixed length. Data is recorded on the optical disk, or data recorded on the optical disk is reproduced, and the address data (prepit string) in the header part is alternately formed for the groove and the land. RAM drive devices have been developed.
[0003]
In such an optical disc device or DVD-RAM drive device, track-on at the time of seek or track jump is performed near the target point, but if a large shake such as a defect occurs near the target point, the track-on is normally performed. Not done.
[0004]
[Problems to be solved by the invention]
As described above, in an optical disk device or a DVD-RAM drive device, track-on at the time of seek or track jump is performed near the target point, but if a large shake such as a defect occurs near the target point, the track-on is normal. There was a problem that was not done.
[0005]
Therefore, an object of the present invention is to provide a tracking method for an optical disc apparatus and a tracking method for a DVD-RAM drive apparatus that can normally perform track-on at the time of seek or track jump.
[0006]
[Means for Solving the Problems]
The tracking method of the optical disk apparatus of the present invention has a groove and land recording track for recording spiral or concentric data, and a header portion and data consisting of address data consisting of a groove and land of a certain length are recorded. Data is recorded on an optical disk having a plurality of recording areas composed of a data area, and the header address is alternately formed for grooves and lands, or data recorded on an optical disk A method of tracking an optical disc apparatus for reproducing, wherein light is collected on the optical disc by a condensing means, the light from the optical disc is detected by the condensing, and tracking on the track of the optical disc is performed based on the detection signal. Generate an error signal, and in this generated tracking error signal Generates a signal that reduces the fluctuation of the header part by passing through the frequency part, generates a slice level from this generated signal, outputs the outer head detection signal by comparing the tracking error signal with the slice level Further, the tracking error signal is compared with the slice level to output an inner head detection signal, a head portion detection signal is output from the outer head detection signal and the inner head detection signal, and the tracking error signal Control for turning on the light converging means in a data area other than the header portion of the optical disc is performed using a header portion detection signal.
[0007]
The tracking method of the DVD-RAM drive device of the present invention has groove and land recording tracks for recording spiral or concentric data, and a header part and data consisting of address data consisting of grooves and lands of a fixed length. Data is recorded on a DVD-RAM disk having a plurality of recording areas composed of data areas to be recorded, and addresses of the header section are alternately formed for grooves and lands, or DVD- A DVD-RAM drive device tracking method for reproducing data recorded on a RAM disk, wherein the light is condensed on the DVD-RAM disk by a light collecting means, and the light from the DVD-RAM disk is detected. Based on this detection signal, the track for the track of the DVD-RAM disc is recorded. A tracking error signal is generated, and a low-frequency portion of the generated tracking error signal is passed to generate a signal with reduced fluctuations in the header portion. A slice level is generated from the generated signal, and the tracking error is generated. The signal is compared with the slice level to output an outer head detection signal, the tracking error signal is compared with the slice level to output an inner head detection signal, and the outer head detection signal and the inner head detection signal are output. A head part detection signal is output, and the generated tracking error signal is used to control to track on the light condensing means in a data area other than the header part of the DVD-RAM disk using the header part detection signal. It is characterized by that.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an optical disk device such as a DVD-RAM drive device. This optical disk apparatus records data on the optical disk 1 using focused light or reproduces recorded data.
[0017]
The optical disk 1 is formed by coating a surface of a substrate formed in a circle with glass or plastics, for example, with a metal film layer such as tellurium or bismuth in a donut shape, and has both concentric or spiral grooves and lands. Is a phase change type rewritable disc in which address data is recorded at predetermined intervals by a recording mark in a mastering process.
[0018]
As shown in FIG. 2, the optical disk 1 is divided into a plurality of zones 1a made up of a plurality of tracks in the radial direction. The clock signal for each zone 1a,... Is the same, and the rotational speed (speed) of the optical disc 1 for each zone 1a,... Is different (slower as it goes from the inner circumference to the outer circumference). The number of sectors per track is different for each zone 1a,. The relationship between the speed data as the rotation speed for each zone 1a,... And the number of sectors per track is recorded in the table 2a of the memory 2 as shown in FIG.
[0019]
Each zone 1a of the optical disk 1, the ... track, the header portion 1 _1, each address and the like are recorded, ... are previously pre-formatted for each sector.
[0020]
The header portion 1 ₁ is configured in forming the groove, it is formed. The header 1 _1, as shown in FIG. 4, is composed of a plurality of pits 101 are pre-formatted as shown in Figure the groove 102, the center of the pits 101 of the groove 102 and the land 103 It exists at the same tangent line.
[0021]
As shown in FIG. 4, pit row ID1 is the header portion of groove 1, pit row ID2 is the header portion of land 1, pit row ID3 is the header portion of groove 2, pit row ID4 is the header portion of land 2, and pit row ID5. Is the header portion of the groove 3 and the pit row ID 6 is the header portion of the land 3.
[0022]
Therefore, the headers for grooves and the headers for lands are formed alternately (staggered).
A format for each sector of each zone 1a of the optical disc 1 is shown in FIG.
[0023]
5, one sector is composed of 2697 bytes (bytes), (corresponding to the header portion 1 ₁₎ 128-byte header area, a mirror mark region of 5 bytes, and a recording area of 2564 bytes.
[0024]
The channel bits recorded in the sector are in the form of 8-16 code modulation of 8 bits of data into 16 bits of channel bits.
The header area is an area where predetermined data is recorded when an optical disc is manufactured. This header area is composed of four address areas PID1, PID2, PID3, and PID4.
[0025]
Each address area PID1 to PID4 consists of 46 bytes or 18 bytes, a 36-byte or 8-byte synchronous code portion VFO (Variable Frequency Oscillator), a 3-byte address mark AM (Address Mark), a 4-byte address portion PID. (Position Identifier) is composed of a 2-byte error detection code IED (ID Error Detection Code) and a 1-byte postamble PA (Postambles).
[0026]
The address areas PID1 and PID3 have a 36-byte synchronization code part VFO1, and the address areas PID2 and PID4 have an 8-byte synchronization code part VFO2.
[0027]
The synchronization code parts VFO1 and 2 are areas for pulling in the PLL, and the synchronization code part VFO1 records “36” bytes (channel bits: 646 bits) of “010... The synchronization code portion VFO2 is a recording of “8” bytes (128 bits in channel bits) of continuous “010...” In channel bits.
[0028]
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 that does not appear in the data portion “0100100000000100” is used.
[0029]
Address portions PID1 to PID4 are areas in which sector addresses (including ID numbers) as 4-byte address information are recorded.
ID number, for example, in the case of PID1 is "1", a number indicating the ordinal number of inner being overwritten four times with one of the header portion 1 _1.
[0030]
The 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.
[0031]
Postamble PA includes a state information necessary for demodulation and has a role of poling as the header portion 1 ₁ is completed by a space.
The mirror mark area is used for offset correction of a tracking error signal, timing generation of a land / groove switching signal, and the like.
[0032]
The recording area is composed of a gap area of 17 to 19 bytes, a VFO3 area of 50 bytes, a data area of 2418 bytes, a guard data area of 30 bytes, and a buffer area of 47 to 49 bytes.
[0033]
The gap region is a region where nothing is written.
The VFO3 area is also an area for PLL lock, but it is also an area intended to synchronize byte boundaries by inserting a synchronization code into the same pattern.
[0034]
The data area is an area composed of a synchronization code, ECC (Error Collection Code), EDC (Error Detection Code), user data, and the like.
The guard data area is an area provided in order to prevent the terminal degradation at the time of repeated recording unique to the phase change recording medium from reaching the data area.
[0035]
Buffer area, so that the data area is not applied to the next header portion 1 _1, which is an area provided for absorbing and rotation fluctuation of the motor for rotating the optical disc 1.
[0036]
The reason why the gap area is expressed as 17 to 19 bytes is that random shift is performed. Random shift is to shift the data writing start position to alleviate repeated 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 to 2697 bytes.
[0037]
In FIG. 1, the optical disk 1 is rotated by a motor 3 at, for example, a different number of rotations for each zone. The motor 3 is controlled by a motor control circuit 4. Data recording and reproduction with respect to the optical disc 1 are performed by the optical head 5. The optical head 5 is fixed to a drive coil 7 constituting a movable part of the linear motor 6, and the drive coil 7 is connected to a linear motor control circuit 8.
[0038]
A speed detector 9 is connected to the linear motor control circuit 8, and a speed signal of the optical head 5 detected by the speed detector 9 is sent to the linear motor control circuit 8. A permanent magnet (not shown) is provided at the fixed portion of the linear motor 6, and the optical head 5 is moved in the radial direction of the optical disk 1 when the drive coil 7 is excited by the linear motor control circuit 8.
[0039]
The optical head 5 is provided with an objective lens 10 supported by a wire or a leaf spring (not shown). The objective lens 10 can be moved in the focusing direction (lens optical axis direction) by driving the drive coil 11, and can be moved in the tracking direction (direction orthogonal to the optical axis of the lens) by driving the drive coil 12. Is possible.
[0040]
A laser beam is emitted from the semiconductor laser oscillator 9 by the drive control of the laser control circuit 13. The laser control circuit 13 includes a modulation circuit 14 and a laser drive circuit 15 and operates in synchronization with a recording clock signal supplied from the PLL circuit 16. The modulation circuit 14 modulates the recording data supplied from the error correction circuit 32 into a signal suitable for recording, that is, 8-16 modulation data. The laser drive circuit 15 drives the semiconductor laser oscillator (or argon neon laser oscillator) 19 according to the 8-16 modulation data from the modulation circuit 14.
[0041]
A PLL (Phase Locked Loop) circuit 16 divides the basic clock signal generated from the crystal oscillator 17 by a frequency division value set by the CPU 30 at the time of recording or a time interval at which the header portion 11 on the optical disc ₁ is reproduced ( The frequency is divided to a frequency corresponding to (header interval), thereby generating a recording clock signal, and at the time of reproduction, a reproduction clock signal corresponding to the reproduced synchronization code is generated. The PLL circuit 16 selectively outputs a clock signal for recording or reproduction in accordance with a control signal from the CPU 30 and a signal from the binarization circuit 41 of the data reproduction circuit 18.
[0042]
A laser light beam emitted from the semiconductor laser oscillator 19 is irradiated onto the optical disc 1 through the collimator lens 20, the half prism 21, and the objective lens 10. The reflected light from the optical disk 1 is guided to the photodetector 24 through the objective lens 10, the half prism 21, the condenser lens 22, and the cylindrical lens 23.
[0043]
The light detector 24 includes four divided light detection cells 24a, 24b, 24c, and 24d. Among these, the output signal of the photodetection cell 24a is supplied to one end of the adder 26a through the amplifier 25a. The output signal of the photodetection cell 24b is supplied to one end of the adder 26b through the amplifier 25b. The output signal of the photodetection cell 24c is supplied to the other end of the adder 26a through the amplifier 25c. The output signal of the photodetection cell 24d is supplied to the other end of the adder 26b via the amplifier 25d.
[0044]
Further, the output signal of the photodetection cell 24a is supplied to one end of the adder 26c via the amplifier 25a. The output signal of the photodetection cell 24b is supplied to one end of the adder 26d through the amplifier 25b. The output signal of the photodetection cell 24c is supplied to the other end of the adder 26d through the amplifier 25c. The output signal of the photodetection cell 24d is supplied to the other end of the adder 26c through the amplifier 25d.
[0045]
The output signal of the adder 26a is supplied to the inverting input terminal of the differential amplifier OP2, and the output signal of the adder 26b is supplied to the non-inverting input terminal of the differential amplifier OP. The differential amplifier OP2 outputs a signal related to the focus point according to the difference between both output signals of the adders 26a and 26b. This output is supplied to the focusing control circuit 27. The output signal of the focusing control circuit 27 is supplied to the focusing drive coil 12. Thereby, the laser light beam is controlled to be always just focused on the optical disc 1.
[0046]
The output signal of the adder 26c is supplied to the inverting input terminal of the differential amplifier (signal generating means) OP1, and the output signal of the adder 26d is supplied to the non-inverting input terminal of the differential amplifier OP1. The differential amplifier OP1 outputs a tracking error signal corresponding to the difference between both output signals of the adders 26c and 26d. This output is supplied to the tracking control circuit 28 and the header part detection circuit 40. The header part detection circuit 40 outputs a header part detection signal in response to the tracking error signal from the differential amplifier OP1, and this header part detection signal is supplied to the tracking control circuit 28. The tracking control circuit 28 generates a track drive signal according to the tracking error signal from the differential amplifier OP1 and the header portion detection signal from the header portion detection circuit 40.
[0047]
The track drive signal output from the tracking control circuit 28 is supplied to the drive coil 11 in the tracking direction. A tracking error signal used in the tracking control circuit 28 is supplied to the linear motor control circuit 8.
[0048]
By performing the focusing and tracking described above, the sum signal of the output signals of the photodetector cells 24a,... 24d of the photodetector 24, that is, the adder 26e, which is the addition of both output signals of the adders 26c and 26d, is added. The output signal reflects the change in reflectance from the pits (recording data) formed on the track. This signal is supplied to the data reproduction circuit 18. The data reproduction circuit 18 reproduces the recorded data based on the reproduction clock signal from the PLL circuit 16.
[0049]
Further, the data reproduction circuit 18 detects a sector mark in the preformat data based on the output signal of the adder 26e and the reproduction clock signal from the PLL circuit 16, and binarizes supplied from the PLL circuit 16. Based on the signal and the reproduction clock signal, the track number and sector number as address information are reproduced from the binarized signal.
[0050]
The reproduction data of the data reproduction circuit 18 is supplied to the error correction circuit 32 via the bus 29. The error correction circuit 32 corrects the error with an error correction code (ECC) in the reproduction data, or adds an error correction code (ECC) to the recording data supplied from the interface circuit 35 and outputs the data to the memory 2.
[0051]
The reproduction data subjected to error correction by the error correction circuit 32 is supplied to an optical disk control device 36 as an external device via the bus 29 and the interface circuit 35. Recording data issued from the optical disk control device 36 is supplied to the error correction circuit 32 via the interface circuit 35 and the bus 29.
[0052]
When the objective lens 10 is moved by the tracking control circuit 28, the linear motor 6, that is, the optical head 5 is moved by the linear motor control circuit 8 so that the objective lens 10 is positioned near the center position in the optical head 5. .
[0053]
The D / A converter 31 is used to exchange data between the focusing control circuit 27, the tracking control circuit 28, the linear motor control circuit 8, and the CPU 30 that controls the entire optical disk apparatus.
[0054]
The motor control circuit 4, linear motor control circuit 8, laser control circuit 15, PLL circuit 16, data reproduction circuit 18, focusing control circuit 27, tracking control circuit 28, error correction circuit 32, etc. are controlled by the CPU 30 via the bus 29. Is done. The CPU 30 performs a predetermined operation by a program recorded in the memory 2.
[0055]
For example, as shown in FIG. 6, the header part detection circuit 40 includes a low-pass filter 41, a slice level generation part 42, comparators 43 and 44, and an OR gate 45.
[0056]
As shown in FIG. 7A, the low-pass filter 41 passes a low-frequency portion in the tracking error signal supplied from the differential amplifier OP1, thereby generating a signal with reduced fluctuation in the header portion. . The slice level generation unit 42 generates a slice level based on the signal from the low pass filter 41. The comparator 43 compares the tracking error signal supplied from the differential amplifier OP1 with the slice level from the slice level generation unit 42, and according to detection of the header portion on the disk outer side (outside) above the slice level, An outer header detection signal as shown in FIG. 7B is output. The comparator 44 compares the tracking error signal supplied from the differential amplifier OP1 with the slice level from the slice level generation unit 42, and according to detection of a header portion on the inner side of the disk (inner side) below the slice level. The inner header detection signal as shown in FIG. 7C is output. The OR gate 45 takes the OR of the outer header detection signal from the comparator 43 and the inner header detection signal from the comparator 44 to output a header part detection signal as shown in FIG.
[0057]
Note that the cases (a) to (d) in FIG. 7 are signals when tracking to the land. When tracking to the groove, the inner header is first and the outer header is behind.
[0058]
Next, the tracking operation in the above configuration will be described with reference to FIGS.
For example, it is assumed that a tracking control circuit 28 performs tracking control using a signal detected by the optical head 5 in an optical disk apparatus.
[0059]
8 shows a tracking error signal during the tracking operation, conventionally, seek and during the track jump, the track-on in the header area is swung header by the above-described header part 1 ₁ of the detection as shown in FIG awake I was doing. Therefore, if you are happening swung header by detecting the header portion 1 _1, track-on has not been successful.
[0060]
Therefore, at the time of seek and track jump in the present invention, the header detection circuit 40 generates the header detection signal shown in FIG. 9B from the tracking error signal shown in FIG. The tracking control circuit 28 performs track-on control in a data area other than the header area detected by the header part detection signal.
[0061]
As described above, according to the embodiment of the present invention, when seek or track jump is performed, track control often fails in the header area due to many track ons, but the header area is detected. By performing tracking control in a data area other than the header area, track-on failure of seek or track jump can be reduced.
[0062]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a tracking method for an optical disc apparatus and a tracking method for a DVD-RAM drive apparatus that can normally perform track-on at the time of seek or track jump.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an optical disc apparatus for explaining an embodiment of the present invention.
FIG. 2 is a diagram for explaining a format example of an optical disc.
FIG. 3 is a diagram for explaining a table in which speed data values corresponding to the number of rotations of the optical disk for each zone are stored.
FIG. 4 is a diagram for explaining preformat data in a header part.
FIG. 5 is a diagram showing a sector format of an optical disc.
FIG. 6 is a block diagram showing a configuration of a header part detection circuit.
FIG. 7 is a diagram showing signal waveforms of a main part of a header part detection circuit.
FIG. 8 is a waveform diagram showing a tracking error signal during a tracking operation.
FIG. 9 is a waveform diagram showing a tracking error signal and a header detection signal.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical disk 1 ₁ ... Header part 5 ... Optical head (condensing means)
24... Photodetector 28... Tracking control circuit (control means)
30 ... CPU
36: Optical disk control device 40: Header section detection circuit (header section detection means)
41 ... Low-pass filter 42 ... Slice level generators 43, 44 ... Comparator 45 ... OR gate

Claims (2)

It has groove and land recording tracks for recording spiral or concentric data, and has a plurality of recording areas consisting of a header section made up of address data and a data area in which data is recorded. A tracking method for an optical disc apparatus that records data on an optical disc in which the address of the header portion is alternately formed for a groove and a land, or reproduces the data recorded on the optical disc. ,
The light is collected on the optical disk by the light collecting means, the light from the optical disk is detected by the light collection, and a tracking error signal for the track of the optical disk is generated based on the detection signal, and the generated tracking is performed. A signal in which the fluctuation of the header part is reduced by passing the low frequency part in the error signal is generated, a slice level is generated by the generated signal, the tracking error signal is compared with the slice level, and the outer head A detection signal is output, the tracking error signal is compared with the slice level, an inner head detection signal is output, a head portion detection signal is output from the outer head detection signal and the inner head detection signal, and the tracking error is output. By using the header part detection signal, Tracking method of the optical disk device characterized by the data area other than the header portion of the optical disk has the condensing means so as to perform control to track-on. It has groove and land recording tracks for recording spiral or concentric data, and has a plurality of recording areas consisting of a header section made up of address data and a data area in which data is recorded. A DVD-ROM that records data on a DVD-RAM disc having the header address alternately formed for grooves and lands, or reproduces data recorded on a DVD-RAM disc. A tracking method for a RAM drive device,
Condensing light on the DVD-RAM disk by a light collecting means, detecting light from the DVD-RAM disk, and generating a tracking error signal for the track of the DVD-RAM disk based on the detection signal; A signal in which the fluctuation of the header portion is reduced by passing a low frequency portion in the generated tracking error signal is generated, a slice level is generated by the generated signal, and the tracking error signal is set as the slice level. The outer head detection signal is output in comparison, the tracking error signal is compared with the slice level, the inner head detection signal is output, and the head part detection signal is output from the outer head detection signal and the inner head detection signal. and, by the generated tracking error signal Tracking process of DVD-RAM drive apparatus being characterized in that to perform the control for track-on the condensing means in the data area other than the header portion of the DVD-RAM disc using the header portion detection signal.

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