JP2001014694A - Disk drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a stable tracking servo control performable even when a beam spot scans a linking section. SOLUTION: In a normal reproducing, switches 70a and 70d are connected to terminals 'a' side to bypass tracking error signals TE. In a linking section, the switches 70a and 70d are switched to terminals 'b' side to supply the signals TE to a hold circuit 70b so that low region components of the inputted tracking error signals TE are outputted. The switches 70a and 70d are controlled by control signals Cs2 supplied from a system controller based on linking signals, address information of the linking section, or the strength of reflected light beams from a disk. Thus, tracking error signals TE are held over a portion or all portion of the linking section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a disk drive capable of holding a tracking error signal corresponding to a data linking portion.

[0002]

2. Description of the Related Art CD (Compact Disc) and CD-ROM (Com
Disc-shaped optical recording media such as pact Disc-Read Only Memory) have become widespread. These CDs and CD-ROMs
At the time of manufacturing, a minute concave portion (physical pit) is formed on the surface of the plastic substrate, and information is recorded by this pit row. The pit train itself is used as a track, and the light beam spot for signal reproduction traces the track based on the pit train. That is, media such as CDs and CD-ROMs are read-only media, and cannot be added or rewritten after manufacturing.

On the other hand, in recent years, a write-once CD-R (R
Discs capable of recording and reproducing data, such as ecordable and rewritable CD-RWs (ReWritable), have become widespread. In these recording media, grooves as guide grooves are formed in a manufacturing process so that a light beam spot can properly trace in a recording area. In the case of a CD-R, data recording is performed by modulating the intensity of a light beam spot, thereby deforming the recording layer on the groove to form physical pits. Also CD
In the case of -RW, this is performed by forming phase pits by a so-called phase change method.

In recent years, DVDs (Digital Versataile Discs or Digital
l Video Discs), read-only discs such as DVD-ROMs, etc., have also been known.
A recordable disk medium such as a DVD + RW having a recording capacity substantially equivalent to a D-ROM has also been proposed.

[0005]

In a phase change type disk, a recording film is heated by a laser beam that modulates recording data, and a phase transition between a crystalline state and an amorphous state is performed. Recording is performed by forming a pattern corresponding to the recording data. When recording is performed on such a disk, data is recorded on a recording area formed in advance by a format process corresponding to the disk based on a required data unit. That is, when data recording is performed, the start position and the end position are determined. For this reason, for example, when additional recording of data is performed, writing is performed following data that has already been recorded. In this case, in order to match the rear end portion of the existing data with the recording start position of the data to be newly recorded, a writing connection area for performing overwriting is formed.

[0006] Therefore, when data writing is performed, data writing involving laser heating is repeatedly performed in a region where writing is performed on the disk. That is, at a position corresponding to a specific address where rewriting is repeatedly performed, the recording film is likely to be deteriorated. This deterioration of the recording film is attributed to thermal flow of the recording film due to writing at a high temperature by laser heating, which is a phenomenon called material flow.

It is difficult to detect a legitimate reproduction signal from a recording area deteriorated due to such a material flow phenomenon. If a high-quality reproduction signal cannot be detected as described above, and a tracking error signal is generated from the reproduction signal, a state may occur in which it is difficult to generate the tracking error signal.

[0008] For example, a tracking error signal is generated by a photodetector divided into four regions.
The reflected light amount of the laser beam applied to the disk in each area is detected as a light receiving current, and is generated based on four light receiving currents (information signals read from the disk signal surface). That is, if the state of the recording film is degraded due to the material flow phenomenon, the degraded state affects the amount of received light, and the tracking error signal does not correspond to the current relative position between the track and the beam spot. Would. Further, for example, by performing the writing connection, a phase shift may occur between the existing data and the added data, and the tracking error signal is also deteriorated by the phase shift. As described above, the tracking error signal is degraded in the writing connection region where the material flow phenomenon and the phase shift have occurred. Therefore, in the tracking control signal generated based on the tracking error signal, the beam spot corresponds to the track. There is a problem that it is difficult to perform control for scanning at a regular position.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a laser which is constituted by a plurality of areas and is irradiated onto a signal recording surface of a disk-shaped recording medium via an objective lens. A light amount signal output unit that detects a reflected light of light in each of the regions and outputs a light amount signal according to a reflected light amount, and based on the light amount signal corresponding to each region output from the light amount signal output unit, A relative position signal generating means for generating a relative position signal indicating a relative position between the track formed on the signal recording surface and the laser beam; and detecting a writing connection region where data writing is performed on the signal recording surface. Detecting means, and the laser light, when scanning a writing connection area where data writing is performed on the signal recording surface, holding means for holding the relative position signal, It includes a tracking drive control means for driving the objective lens in the tracking direction of the disc-shaped recording medium on the basis of the serial relative position signal constituting the disk drive device.

According to the present invention, since the relative position signal is held in the writing connection area, the relative position control between the track and the laser light can be performed even when a required light amount signal cannot be obtained in the writing connection area. Can be realized.

[0011]

Embodiments of the present invention will be described below. In the present embodiment, a disk drive device capable of recording and reproducing data for a predetermined type of disk is provided. The following description will be made in the following order. 1. 1. a disk drive device; 2. Generation of tracking error signal Data structure 4. Keep tracking error signal

1. Disk Drive Device The configuration of the disk drive device of the present embodiment will be described with reference to FIG. The disk D shown in this figure is mounted on a turntable 7 and is rotated at a constant linear velocity (CLV) or a constant angular velocity (CAV) by a spindle motor 6 during a reproducing operation. Then, the data recorded on the signal surface of the disk D is read by the optical pickup 1.

The optical pickup 1 includes a laser diode 4 as a light source of laser light, an optical system including a polarizing beam splitter and an objective lens 2, a photodetector 5 for detecting laser light reflected on the disk D, and the like. It is configured. Here, the objective lens 2 is movably supported by the biaxial mechanism 3 in the tracking direction and the focus direction.

Various signals generated by the RF amplifier 9 are supplied to a binarization circuit 11 and a servo processor 14. In other words, the reproduced RF signal from the RF amplifier 9 is
To push-pull signal PP and focus error signal F
E, the pull-in signal PI is supplied to the servo processor 14. The tracking error signal TE is supplied to the servo processor 14 via the hold unit 70.

The reproduced RF signal output from the RF amplifier 9 is binarized by a binarization circuit 11 to generate a binarized signal (for example, an EFM signal (8-14 modulated signal) or an EFM + signal).
The signals are supplied to the encoder / decoder 12 and a PLL (Phase Locked Loop) circuit unit 20.

The PLL circuit 20 generates a reproduction clock PLCK synchronized with the channel bit frequency of the input binary signal. The reproduction clock PLCK is used as a reference clock for signal processing or the like at the time of reproduction, and is supplied to, for example, the encoder / decoder 12 as shown in FIG. . PLL circuit section 2
In this embodiment, reference numeral 0 denotes, for example, a configuration as shown in FIG. 2, for example, a phase / frequency comparator 21, a low-pass filter 22, a sample-and-hold unit 23, a VCO
(Voltage Controlled Oscilltor) 24 and the like.

In the phase / frequency comparator 21, the binarized signal and the reproduction clock PLCK output from the VCO 24 are output.
Are compared, and the phase error detected by the phase comparator 21 is converted to a voltage level corresponding to the phase error by passing through the low-pass filter 22. Then, this voltage level is supplied to the VCO 24 via the sample and hold unit 23 as a phase error signal. Then, by controlling the oscillation frequency of the VCO 24 with the phase error signal, a reproduction clock PLCK synchronized with the binarized signal is generated.

The sample / hold section 23 has a phase /
The voltage V1 as a phase error signal output from the frequency comparator 21 can be held based on, for example, a control signal Cs1 supplied from the system controller 10. Therefore, the voltage V1 is supplied from the system controller 10. A switch SW for performing on / off control based on the control signal Cs1 to be performed, the amplifier 23a, a charging capacitor C1, and the like are provided.

The control signal Cs1 is turned on by the switch SW when the decoding section of the encoder / decoder 12 detects a required synchronization frame added to the beginning of a required reproduction data unit from the binarized reproduction signal. This is a signal for controlling the connection state. Thus, when the switch SW is turned on, the voltage V1 is amplified by the amplifier 23a and supplied to the VCO 24 as the voltage V2. When the switch SW is turned on, the capacitor C1 is charged until it reaches the voltage V1. When the synchronous frame is not detected, that is, in a period corresponding to a writing connection area (linking unit) described later, the switch SW is turned off. However, as a control voltage supplied to the VCO 24, The required level is maintained by the voltage V1 charged in the capacitor C1 when the ON period is set. That is, for example, even when the linking unit or the like cannot correctly detect the synchronization frame, the input voltage of the VCO 24 can be maintained by the voltage V1 charged in the capacitor C1. Therefore, the frequency of the reproduction clock PLCK can be kept substantially constant.

A configuration for obtaining a stable reproduction clock PLCK while maintaining the control voltage of the VCO 24 is disclosed in Japanese Patent Application No. 9-46671 as a prior application filed by the present applicant. I have.

At the time of reproduction, the decoding unit of the encoder / decoder 12 shown in FIG. 1 performs EFM demodulation or EFM + demodulation, and further performs error correction processing (RS-PC system, CIRC system, etc.) according to a predetermined system. Perform disk D
The reproduction of the information read from is performed. The data decoded by the encoder / decoder 12 is supplied to a host computer (not shown) via the interface unit 13. Also, the encoder / decoder 1
Numeral 2 is adapted to detect a required synchronization frame added to the head of a required reproduction data unit from the binarized reproduction signal, and to supply the detection result to the system controller 10. Has been. Also,
A required interpolation process can be performed on the detected synchronization frame.

When data is recorded on the disk D, for example, data supplied from a host computer (not shown) is sent to the encoder of the encoder / decoder 12 via the interface 13.

In the encoding unit, an error correction code is added to the data input from the interface unit 13 according to a predetermined method, and the data is encoded.
Further, predetermined modulation processing for recording on the disk D is performed to generate recording data WD. This recording data WD is supplied to the laser driver 18. Laser driver 18
Then, modulation is performed based on the input recording data WD to generate a laser diode driving signal in which a required recording level and erasing level are combined to generate a laser diode driving signal.
Drive. Thus, data recording is performed according to the phase change method.

The servo processor 14 generates various servo drive signals for focus, tracking, thread, and spindle from the focus error signal FE, the tracking error signal TE, the push-pull signal PP, and the like, and executes a servo operation. That is, the focus error signal FE,
A focus drive signal FDR and a tracking drive signal TDR are generated according to the tracking error signal TE and supplied to the biaxial driver 16.

The biaxial driver 16 includes, for example, a focus coil driver 16a and a tracking coil driver 16b. The focus coil driver 16a supplies the drive current generated based on the focus drive signal FDR to the focus coil of the biaxial mechanism 3 to drive the objective lens 2 in the direction of moving toward and away from the disk surface. The tracking coil driver 16b supplies the drive current generated based on the tracking drive signal TDR to the tracking coil of the biaxial mechanism 3 to drive the objective lens 2 to move in the disk radial direction. Thereby, the optical pickup 1, the RF amplifier 9, the servo processor 1
4. A tracking servo loop and a focus servo loop by the two-axis driver 16 are formed.

The servo processor 14 supplies a spindle drive signal generated from the spindle error signal SPE to the spindle motor driver 17. The spindle motor driver 17 applies, for example, a three-phase drive signal to the spindle motor 6 in accordance with the spindle drive signal, and drives the spindle motor 6 to rotate at a required rotational speed. Further, the servo processor 14 generates a spindle drive signal in response to a spindle kick (acceleration) / brake (deceleration) signal from the system controller 10, and causes the spindle motor driver 17 to start or stop the spindle motor 6. .

The servo processor 14 generates a thread drive signal based on, for example, a thread error signal obtained from a low-frequency component of the tracking error signal TE or an access execution control from the system controller 10 and supplies the thread drive signal to the thread driver 15. . The thread driver 15 responds to the thread drive signal by the thread mechanism 8.
Drive. The sled mechanism 8 is a mechanism for moving the entire optical pickup 1 in the radial direction of the disk. The sled driver 15 drives a sled motor inside the sled mechanism 8 in accordance with a sled drive signal, so that the optical pickup 1 can slide properly. Is performed.

Further, the servo processor 14 also performs light emission drive control of the laser diode 4 in the optical pickup 1. The laser diode 4 is a laser driver 18
The servo processor 14 generates a laser drive signal for performing laser emission at the time of recording / reproduction based on an instruction from the system controller 10, and generates a laser drive signal based on an instruction from the system controller 10.
To supply. In response, the laser driver 18 drives the laser diode 4 to emit light.

The hold section 70 is adapted to hold the tracking error signal TE at the timing of reading the linking section. This hold unit 70
, A control signal Cs2 is supplied from the system controller 10 in accordance with the timing of reading the linking unit. The holding unit 70 will be described later.

The above-described various operations such as servo and encoding / decoding are controlled by a system controller 10 including a microcomputer and the like. For example, operations such as reproduction start, end, track access, fast forward reproduction, and fast reverse reproduction are realized by the system controller 10 controlling the operation of the optical pickup 1 via the servo processor 14.

The system controller 10 controls the sample / hold section 23 of the PLL circuit 20 to hold the control voltage of the VCO 24 based on the detection state of the synchronous frame in the encoder / decoder 12.
In parallel with outputting 1 and holding the control voltage,
It is possible to perform control for interrupting synchronization frame extraction and interpolation processing. Further, it generates a control signal Cs2 for holding the tracking error signal TE in accordance with the timing of reproducing the linking section, and supplies the control signal Cs2 to the hold section 70.

It should be noted that the decoding unit is, for example, a linking signal which is set to a high level when the linking unit is detected based on the binarized reproduction signal (see FIG. 12).
) Can be supplied to the system controller 10. Therefore, the system controller 10 can perform control for holding the tracking error signal TE based on the linking signal. The address where the linking portion is formed on the recording surface of the disk D is recorded at a required position on the disk D, for example, as recording management information of the disk. Then, by reading these pieces of information, the position (address) of the linking portion formed on the disk D can be ascertained. That is, for example, when the reproducing operation is performed, it is possible to predict the timing of scanning the linking unit from the address information. Therefore, the tracking error signal TE at a required timing before the linking unit can be held in advance.

FIG. 3 shows a structural example of an optical system in the optical pickup 1. In the optical system shown in this figure, a laser beam output from a laser diode 4 is collimated by a collimator lens 101 and then reflected 90 degrees by a beam splitter 102 to a disk D side. Is irradiated. The light reflected by the disk D enters the beam splitter 102 via the objective lens 2, passes through as it is, and reaches the condenser lens 103. After being condensed by the condenser lens 103, the light is incident on the photodetector 5 via a cylindrical lens (cylindrical lens) 104.

Here, the center wavelength of the laser diode 4 is set according to the type of the disk to be actually reproduced (and recorded), and the numerical aperture NA of the objective lens 2 is also set to the type of the disk to be actually reproduced. Is set corresponding to.

The laser light reflected from the disk D by the reproducing operation of the disk drive device is detected by the photodetector 5 as a light receiving current. And
This light receiving current is output to the RF amplifier 9 shown in FIG. 1 as an information signal read from the disk. The RF amplifier 9 includes a current-voltage conversion circuit, an amplification circuit, a matrix operation circuit (RF matrix amplifier), and the like, and generates a necessary signal based on a signal from the photodetector 5. For example, an RF signal as reproduction data, a push-pull signal PP for servo control, and a focus error signal F
E, a tracking error signal TE, a pull-in signal PI which is a so-called sum signal, and the like are generated.

In this case, the photo detector 5 includes
In the direction as shown in FIG. 4A, for example, the detection units A, B,
It is provided with a quadrant detector composed of C and D. In addition,
Hereinafter, the detection signals obtained by the detection units A to D are also referred to as detection signals A to D, respectively.

For the pull-in signal PI, using the detection signals A, B, C, and D, PI = (A + B + C +
D). Since the pull-in signal PI corresponds to the amount of the totally reflected light received from the disk D, it can be said that the pull-in signal PI is a “light intensity signal” indicating the intensity of the reflected light.

For example, when the push-pull signal PP is generated by the quadrant detector 5a, the outputs (detection signals A, B) of the detectors A, B, C, and D of the detector 5a as shown in FIG. , C, D) and the differential amplifier 5
b can be generated by performing the calculation of PP = (A + B)-(C + D).

2. Tracking Error Signal Generation In the RF amplifier 9 of the present embodiment, the detection signals A to
In order to generate the tracking error signal TE based on D, for example, a tracking error signal generation circuit 40 having a configuration shown in FIG. 5 is provided. The tracking error signal generation circuit 40 uses the outputs of the detection units A, B, C, and D of the four-divided photodetector 5a shown in FIG.
For example, a tracking error signal TE detected by a DPD (Differential Phase Detection) method can be generated.

Each output of the detection units A and C is
1 and 42 are supplied to the adder 43. Each output of the detection units B and D is supplied to an adder 46 via buffer amplifiers 44 and 45. The waveform shaping circuits 47 and 48 are configured by, for example, comparators and the like, perform necessary waveform shaping processing on the added signals supplied from the adders 43 and 46, and supply the resultant signals to the phase comparison circuit 50. The phase comparison circuit 50 includes, for example, D flip-flops (D-FF) 51, 52, 53,
4, inverters 55 and 56, OR gates 57 and 58, a differential amplifier 59, a low-pass filter 60, and the like.

In the phase comparison circuit 50, the signal Sa supplied from the waveform shaping circuit 47 is supplied to the clock terminal of the D-FF 52 and the reset terminal R of the D-FF 54.
Further, the signal Sa is supplied to the inverter 55, and after being inverted there, is supplied to the clock terminal of the D-FF 51 and the reset terminal R of the D-FF 53 as a signal Sa−.
On the other hand, the signal Sb supplied from the waveform shaping circuit 48 is D
-The reset terminal of the FF 51 and the clock terminal of the D-FF 53 are supplied. Further, the signal Sb is supplied to the inverter 56 and after being inverted here, the signal Sb−
It is supplied to the reset terminal S of the FF 52 and the clock terminal of the D-FF 54. Further, a power supply voltage is applied to a data input terminal and a set terminal of each of the D-FFs 51 to 54 from a path (not shown).

The OR gate 57 calculates the logical sum of the output signals Sc1 and Sc2 of the D-FFs 51 and 52 and supplies the logical sum (negative input signal Sd1) to the negative input terminal of the differential amplifier 59. The OR gate 58 is connected to the D-FF5
The logical sum of the output signals Sc3 and Sc4 of the first and third output circuits 3 and 54 is calculated, and this logical sum (the positive input signal Sd2) is supplied to the positive input terminal of the differential amplifier 59. The differential amplifier 59 performs a required output according to the difference between the negative input signal Sd1 and the positive input signal Sd2, and the output is output as a tracking error signal TE via a low-pass filter 60.

FIG. 6 is a schematic diagram showing an example of waveform timing for explaining the outline of generating a tracking error signal. FIG. 6A shows a positional relationship between a pit Pit forming a track and a beam spot output from the objective lens 2, wherein the period is a state in which the beam spot follows the track, and the period is a beam. A state in which the spot has shifted to the inner peripheral side of the disk D,
The period indicates a state where the beam spot is shifted to the outside of the disk D. Further, FIG.
6 (c) is a signal obtained by converting the detection signal A and the detection signal C, and FIG. 6 (d) is a signal obtained by adding the detection signal B and the detection signal D in the divided photodetector 5a.
The signal Sb shown in FIG. 4 and the signal Sb shown in FIG.
6F is the signal Sab, FIG. 6F is the signal Sa shown in FIG. 4C, and FIG. 6G is the signal Sa-, FIG. 6H and FIG. ) (J) (k) are D-FF
Output signals Sc1, Sc2 from 51 to D-FF54,
Sc3, Sc4, and FIG. 6 (l) shows the negative input signal Sd1 from the OR gate 57, and FIG.
8 shows a positive input signal Sd2 from FIG.

For example, as shown in the period, the beam spot follows the track, and the signals Sa,
When the phase difference between the signal Sa−, the signal Sb, and the signal Sb− is “0”, the D-FFs 51 to 54 are in a reset state, and the output signals Sc1 to Sc4 are at a low level. As a result, there is no level difference between the negative input signal Sd1 and the positive input signal Sd2 of the differential amplifier 57, and the output of the differential amplifier 57 is at the ground level. Therefore, the tracking error signal TE (not shown) output via the low-pass filter 60 becomes equal to the ground level.

In the state where the beam spot shifts to the inner circumference side of the track as shown in the period, the phase of the signal Sa and the phase of the signal Sa- are shifted more than the phase of the signal Sb and the phase of the signal Sb-. Advance by the angle corresponding to the amount.
As a result, the D-FFs 51 and 52 change their displacement amounts (angles).
Is set for a time corresponding to the output signal Sc1,
Sc2 becomes a high level at a timing according to the amount of displacement. In addition, the D-FFs 53 and 54 remain in the reset state, and the output signals Sc3 and Sc4 remain at the low level. Therefore, only the negative polarity input signal Sd1 becomes high level, and as a result, a negative polarity positive pulse is output from the differential amplifier 59. The negative polarity pulse passes through the low-pass filter 60, and the tracking error signal is output. TE. That is, the tracking error signal TE at this time becomes a negative level, and its absolute value corresponds to the amount of displacement of the beam spot with respect to the inner circumference side.

Further, in the state where the beam spot shifts to the outer circumference side of the track as shown in the period, the phase of the signal Sa, the phase of the signal Sa- is larger than the phase of the signal Sb, the shift amount of the beam spot. Will be delayed by an angle corresponding to. As a result, the D-FFs 53 and 54 enter the set state for a time corresponding to the amount of displacement (angle), and the output signals Sc3 and Sc4 become high level at a timing corresponding to the amount of displacement. Further, the D-FFs 51 and 52 remain in the reset state, and output signals Sc1 and Sc2 are output.
Remains at low level. Therefore, only the positive polarity input signal Sd2 becomes high level, so that the differential amplifier 59
Outputs a positive-polarity pulse, and the positive-polarity pulse passes through the low-pass filter 60 to be used as the tracking error signal TE. That is, the tracking error signal TE at this time becomes a positive level, and its absolute value corresponds to the amount of displacement of the beam spot with respect to the outer peripheral side.

3. Data Structure FIG. 7 is a schematic diagram illustrating the structure of a sector formed on the recording surface of the disk D. This sector has a frame structure, and is composed of, for example, 26 synchronization frames. Each synchronization frame is composed of a sync code of 32 channel bits (SY0 to SY7) and 13 rows of a data area of 1456 channel bits. An ECC block, which is a data unit for recording / reproducing data on / from a disk described later, is formed by 16 sectors. When this sector is used for linking when writing and linking data, the sector is as shown in FIG. 8 and corresponds to the linking section described above. In the linking section, for example, linking data of 91 bytes is formed corresponding to each sync code. Also, the sync code S following the sync code SY0
The linking data corresponding to Y5 is shown in a divided state in order to perform writing connection as described later.

As described above, for example, when data is additionally recorded on the disk D, writing is performed following data that has already been recorded. FIG. 9 is a schematic diagram illustrating a data frame in a recording area where writing is performed. FIG. 9A shows an ECC (Error Collec
tion Code) Block N-1, N, N + 1, N + 2 ...
·It is shown. Each of these ECC blocks is a 32-kbyte recording area composed of, for example, 16 sectors.
The block is a block constituting a recording sector to which a required scramble process is performed and an error correction code is added. The ECC block is a recording unit when data is recorded on the disk D. Each of the ECC blocks has a synchronous frame part SYa, SYb, SYc, SYd,
SYe... Correspond to each other. FIG.
In the example shown in (b), the synchronous frame part SYc is formed as a linking part, and is formed by 26 frames (corresponding to one sector) with frame numbers “0” to “25”. Each frame is provided with a required frame code (for example, SY0, SY5, etc.).

In the illustrated example, the previous recording is performed up to the ECC block N, and the current ECC block N + 1
Assuming that the following data was recorded, in such a case, the start position shift
ft... SPS) will be described. In this case, as shown in FIG.
Then, data of (45 bytes-SPSN) is written as a synchronization frame "0" as a linking unit and a synchronization frame "1" in the synchronization frame unit SYc. Then, when recording data of the next ECC block N + 1 or later, recording is started from the continuation of the synchronous frame “1” in the synchronous frame part SYc, but the theoretical recording start position is the position Sp. That is, recording starts from the position Sp as a starting point, and when viewed from the beginning of the synchronous frame “1”, for example, (46 bytes + SPSN +
The data of the synchronization frame “1” is stored from the position 1). For example, when the SPS is “−10”, the recording end point of the previous synchronization frame “1” is the 55th byte from the beginning, and the current recording start point is 36 bytes from the beginning of the synchronization frame “1”. Will be. That is, 19
Byte data will be overwritten.

Such a linking portion is formed every time overwriting is performed on the disk D, but does not function as actual data. Therefore, power calibration for adjusting the output power of the laser light, for example, may be performed using the linking unit. In other words, in the storage area corresponding to the writing connection area, for example, the frequency of irradiation of the recording power beam spot becomes higher than in other recording areas, and in particular, in the area near the head of the linking portion, deterioration occurs due to the material flow phenomenon. It is possible. In addition, by performing writing, the phase of existing data and the added data are shifted. In the linking section, the reproduced RF signal is deteriorated due to such a reason.
When the PD method is applied, the tracking error signal TE is affected, and a stable tracking servo error signal cannot be realized. Also. When a phase shift occurs due to writing, even if a signal generation method other than the DPD method is used, it is difficult to generate the regular tracking error signal TE.

Therefore, in the present embodiment, the linking section holds the above-described control voltage of the VCO 24 to obtain a stable reproduction clock PLCK, and holds the tracking error signal TE to provide a stable tracking drive. The signal TDR is generated. For this reason, the details of the hold circuit 70 shown in FIG. 1 are as shown in FIG. The hold unit 70 includes switches 70a and 70d for selectively switching an input system and an output system of the tracking error signal TE, and includes, for example, resistors R0, R1, R2, a capacitor C, and a comparator 70.
c, etc., it is constituted by a hold circuit 70b having the function of a low-pass filter.

The switches 70a and 70d are arranged such that, for example, in a normal reproducing operation state, the terminal a is selected and the tracking error signal TE supplied to the hold section 70 is output as it is. Also, the switches 70a, 7
0d is switched to the terminal b at a predetermined timing corresponding to the linking unit based on the control signal Cs2 from the system controller 10. Thereby, the holding unit 70
Is output via the hold circuit 70b. In other words, the tracking error signal TE is output while retaining its low-frequency component via the hold unit 70b.

FIG. 11 is a diagram for explaining the frequency component of the tracking error signal TE held by the hold circuit 70b.
Of the tracking error signal T in the horizontal axis direction
The frequency of E is shown. In this figure, the frequency f1 can be expressed as f1 = 1 / 2π (R1 + R2) × C, and the frequency f2 can be expressed as f2 = 1 / 2π × R1 × C. That is, the tracking error signal TE is integrated in the frequency band from the frequency f1 to the frequency f2, and from the hold circuit 70b,
Output is performed in a state where the frequency components of this frequency band are held. In order to stop holding the low-frequency component and bypass the tracking error signal TE again,
The timing for switching the switches 70a and 70c to the terminal a may be any timing within a period corresponding to the linking unit.

FIG. 12 shows the waveforms of the reproduced RF signal, the linking signal, the tracking drive signal, and the tracking error signal TE corresponding to the timing of the linking section. It should be noted that the linking signal shown in FIG. 12B is a high level signal when the linking unit is detected based on the binarized signal. For example, the linking signal is transmitted from the encoder / decoder 12 to the system controller 10.
Supplied to In this figure, for example, in terms of time, 1.2
An example in which the beam spot scans the linking part during the period of ms is shown. Further, since the linking signal goes high in response to the linking section, the system controller 10 may perform control to start holding the tracking error signal TE at the timing when the linking signal goes high.

When the beam spot scans the linking portion, the reproduced RF signal may have a waveform as shown in FIG. 12A due to, for example, a material flow phenomenon. ), The tracking error signal TE generated based on the reproduced RF signal is also disturbed. In this case, in the present invention, FIG.
On the basis of the linking signal shown in FIG. 2B, the system controller 10 outputs a control signal Cs2 to perform control to switch the switches 70a and 70d of the hold circuit 70 to the terminal b side, respectively, so that the tracking error signal TE becomes low. The area is kept. That is,
The servo processor 14 has a tracking error signal TE
Is supplied, and the tracking drive signal TDR generated based on this low frequency component is as shown in FIG. 12 (c).

In the example shown in FIG. 12, in the 1.2 msec period corresponding to the linking section,
The low-frequency component is held for 0 μsec, and thereafter, the switches 70a and 70d are switched to the terminal a to bypass the tracking error signal TE. However, this is merely an example, and the low-frequency component of the tracking error signal TE may be held over the entire period of the linking unit. That is, the period from when the hold of the tracking error signal TE is started to when it is released is not limited to the example shown in FIG.

The tracking error signal TE may be held during the period when the linking signal is at the high level, for example, for all periods (for example, 1.2 msec). However, as shown in this example, for example, 300 to 400 μm from the rise of the linking signal.
By performing the hold in the sec period, it is possible to deal with at least the first half of the linking portion, which is considered to be largely deteriorated by at least the power calibration. Further, the time during which the tracking error signal TE is held is measured by counter means for measuring the operation timing (master clock) of the system controller 10.

Further, in the present embodiment, an example has been described in which the tracking error signal is held by an analog circuit. However, since the timing of scanning the linking portion can be predicted from the position information such as the sector address, for example, the timing at which the normal reproduction RF signal is detected to some extent before the scanning of the linking portion is detected. The tracking error signal may be converted into digital data and stored in a required memory means, and a tracking drive signal may be generated based on the tracking error signal stored in the memory means at the timing of scanning the linking unit. good.

It is also conceivable to detect the linking portion based on the amount of reflected light, for example, as in the case of detecting a defect on the recording surface. In the linking unit, the power calibration is performed as described above, and a mirror unit may be formed in the linking unit by the power calibration.
That is, since the normal reflectance is different in the mirror portion, the linking portion may be detected using the difference in the amount of reflected light, and control for operating the hold circuit 70b may be performed. Such control is performed by, for example, supplying a pull-in signal PI, which is generated by the RF amplifier 9 and is a “light intensity signal” indicating the intensity of reflected light, to the system controller 10. This can be realized by controlling the hold unit 70 based on the PI level.
Further, the detection of the linking portion by the pull-in signal PI and the detection of the linking portion by the timing of the linking signal may be used together.

[0060]

As described above, in the disk drive device of the present invention, the relative position between the track formed on the signal recording surface of the disk and the laser beam can be determined at the timing corresponding to the writing connection area (linking section). The relative position signal (tracking error signal) shown can be held. Therefore, even when the reproduction signal read from the linking unit is disturbed, a stable tracking drive signal can be generated.
Thereby, even when the beam spot scans the linking section, stable tracking servo control can be realized.

Further, the linking unit detects the signal almost accurately on the basis of a signal (linking signal) detected based on the reproduced data obtained by scanning the linking unit and the management information of the disk recorded on the disk. Will be able to

Further, for example, the tracking error signal is held during a period corresponding to part or all of the linking section. For example, due to the material flow phenomenon caused by power calibration, etc.
It is possible to partially correspond to the first half of the linking portion where the degree of deterioration of the recording surface is large. That is, stable tracking servo control can be realized in a part or the entire period of the linking unit.

Further, since the tracking error signal is held based on the level of light reflected from the disk recording surface, for example, when a mirror portion is formed in the linking portion due to a material flow phenomenon due to power calibration or the like. There is an advantage that it becomes possible to respond to

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a disk drive device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a PLL circuit illustrated in FIG. 1;

FIG. 3 is a structural view conceptually showing a structural example of an optical system of the optical pickup.

FIG. 4 is an explanatory diagram showing a detection operation by a photodetector of the optical pickup.

FIG. 5 is a diagram illustrating a configuration example of a tracking error signal generation circuit.

FIG. 6 is a diagram illustrating waveforms at various parts of the tracking error signal generation circuit shown in FIG.

FIG. 7 is a schematic diagram illustrating a structure of a sector formed on a recording surface of a disk.

FIG. 8 is a diagram showing an example of a case where the sector shown in FIG. 7 is used as a linking unit for linking data writing.

FIG. 9 is a schematic diagram illustrating a data frame in a recording area where writing is performed;

FIG. 10 is a diagram illustrating a configuration example of a hold circuit;

FIG. 11 is a diagram illustrating frequency components of a tracking error signal.

FIG. 12 shows reproduction R corresponding to the timing of a linking unit.
FIG. 3 is a diagram illustrating waveforms of an F signal, a linking signal, a tracking drive signal, and a tracking error signal TE.

[Explanation of symbols]

1. Optical pickup, 2. Objective lens, 3. Biaxial mechanism, 4. Laser diode, 5. Photodetector, 5.
a split detector, 5b differential amplifier, 6 spindle motor, 7 turntable, 8 thread mechanism, 9
RF amplifier, 10 system controller, 11 binarization circuit, 12 decoder, 13 interface unit, 14 servo processor, 15 thread driver, 16 two-axis driver, 16a focus coil driver, 16b tracking coil driver, 17
Spindle motor driver, 18 laser driver, 4
0 tracking error signal generation circuit, 70 hold unit, 70, 70d switch, 70b hold circuit,
70c comparator

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kunihiko Miyake 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5D118 AA27 BA01 BB03 BB07 BF01 CA13 CB01 CB05 CC06 CD03 CD06 CD07 CF06

Claims (5)

[Claims] 1. A reflected light of a laser beam, which is constituted by a plurality of areas and is applied to a signal recording surface of a disk-shaped recording medium via an objective lens, is detected in each of the areas, and the reflected light is determined according to the amount of reflected light. A light amount signal output unit for outputting a light amount signal; and a relative position between a track formed on the signal recording surface and the laser light based on a light amount signal corresponding to each area output from the light amount signal output unit. A relative position signal generating means for generating a relative position signal; a detecting means for detecting a writing connection area where data writing is performed on the signal recording surface; and the laser beam writing data on the signal recording surface. When scanning the writing connection area where the connection is performed,
A disk drive device comprising: holding means for holding the relative position signal; and tracking drive control means for driving the objective lens in a tracking direction of the disk-shaped recording medium based on the relative position signal. . 2. The disk drive device according to claim 1, wherein said detecting means detects said writing connection area based on reproduction data obtained by demodulating said light amount signal. 3. The disk drive according to claim 1, wherein said detecting means detects said writing connection area based on required management information recorded on said disk-shaped recording medium. apparatus. 4. The disk drive device according to claim 1, wherein the holding unit holds the relative position signal during a part or the whole of the writing connection area. 5. The disk drive device according to claim 1, wherein the detection unit detects the writing connection area based on the intensity of the reflected light.