JP2002298387A - Disk drive device and information reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk drive device to reproduce information from an optical disk on which a land and a groove (groove part) are formed and to realize an accurate half track jumping operation. SOLUTION: The disk drive device reads the information from a recording medium in which the information is recorded in the land and the groove by scan by a reading means. The disk drive device is characterized by providing an RF amplifier 4 to generate a tracking error signal TE to indicate shift of a scanning position of the reading means and a control part 71 to change the scanning position of the reading means between the adjacent land and groove by reducing transfer rate of the reading means by prescribed acceleration in prescribed period including time in which the tracking error signal TE takes an extreme value is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive for recording and reproducing information on a disk-shaped recording medium, and to an information reading method.

[0002]

2. Description of the Related Art Conventional compact disks (CD) and D
VD-ROMs and the like are optical disks that employ a pit recording method. By scanning an optical pickup along a track on which the pits are formed and measuring reflected light,
The information recorded by the pits is reproduced. here,
The position of the optical pickup in the radial direction of the optical disk is controlled by a tracking error signal. Also,
In the information reproduction of the optical disk as described above, a "track jump operation" for continuously accessing information recorded on physically separated tracks is realized, and the transition from pit to pit of the optical pickup is performed as described above. This is the minimum unit in the track jump operation. In addition,
In such a jump operation, the track jump operation is completed by a one-cycle tracking error signal.

On the other hand, when information is read from an optical disk such as a DVD-RAM having lands and grooves (grooves) formed thereon, information recorded in different structural portions such as lands to grooves or grooves to lands. In some cases, a “half track jump operation” for continuously playing back the data is required. However, in such a case, it is necessary to complete the half-track jump operation during a half cycle of the tracking error signal obtained during the jump operation, and the track jump operation is completed by one cycle of the tracking error signal. However, there is a problem that the conventional control method for causing the above cannot be used as it is.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made in the art of DVD-RAM.
A disk drive device for reproducing information from an optical disk having lands and grooves (grooves) formed thereon,
It is an object of the present invention to provide a disk drive device that realizes an accurate half-track jump operation.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for reading information from a recording medium in which lands and grooves are alternately formed in a radial direction and information is recorded on the lands and grooves by scanning by reading means. Achieved by changing the scanning position of the reading means between adjacent lands and grooves by reducing the moving speed of the reading means by a predetermined acceleration during a predetermined period including a time when the tracking error signal takes an extreme value. Is done.

According to such means, the scanning position of the reading means can be automatically and accurately moved by utilizing the tracking error signal.

Another object of the present invention is to generate a pulse signal which is activated while the tracking error signal exceeds a predetermined threshold value, and to accelerate the reading means to move it to an adjacent land or groove. This is achieved by changing the scanning position of the reading means to an adjacent desired land or groove by negatively accelerating the moving speed of the reading means when the pulse signal is activated.

According to such a means, the scanning position of the reading means can be accurately changed from a land to a groove adjacent to the land or from a groove to a land adjacent to the groove by a simple configuration and method. Can be.

Here, the first pulse signal activated when the tracking error signal becomes larger than the first threshold value and the tracking error signal becomes smaller than the second threshold value. And a second pulse signal that is activated in the event that the pulse signal is activated, and controls the movement of the reading unit in accordance with either the selected first pulse signal or the selected second pulse signal. .

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts. FIG. 1 is a block diagram showing an overall configuration of a disk drive device according to an embodiment of the present invention. As shown in FIG. 1, the disk drive device according to the present embodiment is a device for recording and reproducing information on and from an optical disk 1 mounted thereon, and includes a spindle motor (SPM) 2 and an optical pickup 3. , Two-axis mechanism 3a, RF amplifier 4, servo processor 5, drive circuit 6, binarization circuit 7, clock reproduction circuit 8,
A decoding circuit 9, an error correction circuit 10, a buffer memory 11, a data interface 12, a system controller 13, a RAM block 14, a header detection unit 15,
The host computer 4 includes a PID detector 16, a land / groove detector 17, an external data bus 18, a thread mechanism 19, a laser diode 30, an objective lens 34, and a photodetector 37.
It is connected to 0.

In the above, the spindle motor (SP
M) 2 controls the rotation of the turntable on which the optical disc 1 is mounted. The optical pickup 3 irradiates a laser beam to the signal surface of the optical disk 1 by the laser diode 30 and detects reflected light from the signal surface by the photodetector 37, thereby obtaining the optical disk 1.
Of the data recorded in the. Here, the objective lens 34 constituting the optical pickup 3 condenses the laser beam emitted from the laser diode 30 and irradiates the laser beam onto the signal surface of the optical disk 1. The objective lens 34 is moved in the tracking direction by the biaxial mechanism 3a. And movably held in the focus direction. The optical pickup 3 is moved by the thread mechanism 19 to the optical disc 1.
Is movable in the radial direction.

The reflected light detected by the optical pickup 3 is supplied to an RF amplifier 4 as a current signal corresponding to the amount of the light, and the RF amplifier 4 performs current / voltage conversion and matrix calculation processing. Is performed to generate a focus error signal FE and a tracking error signal TE. Further, an RF signal as reproduction information, a PI (pull-in) signal as a sum signal, and the like are generated.

The focus error signal FE and the tracking error signal TE generated by the RF amplifier 4 are supplied to a drive circuit 6 after required processes such as phase compensation and gain adjustment are performed by a servo processor 5. More specifically, the servo processor 5 generates a thread control signal SS for track jump via a built-in low-pass filter (LPF) and supplies it to the drive circuit 6, and focuses in response to an instruction from the system controller 13. A signal SF for a search operation and a signal ST for a track jump operation are supplied to the drive circuit 6. Further, the servo processor 5 generates a track drive signal TD for half-track jump according to the signals JD, HLS, JS, L1, L2 supplied from the system controller 13 and supplies the track drive signal TD to the drive circuit 6. Will be described in detail later.

Further, the drive circuit 6 executes the thread servo control by outputting the track jump thread control signal SS to the thread mechanism 19 as a thread drive signal, and generates a focus drive signal and a tracking drive signal. The focus servo control and the tracking servo control are executed by outputting to the shaft mechanism 3a. Thereby, focus search, track jump / access, and the like of the optical pickup 3 are realized.

On the other hand, the reproduced RF signal generated by the RF amplifier 4 is binarized by a binarization circuit 7 and is subjected to EFM.
A plus signal is generated. Then, the EFM plus signal is supplied to the clock recovery circuit 8, and a recovered clock signal CLK synchronized with the EFM plus signal is extracted and generated.
The reproduced clock signal CLK is supplied as an operation clock in various circuits including the decode circuit and the servo processor 5.

The EFM plus signal from which the clock signal has been extracted as described above is supplied to a decoding circuit 9 and demodulated, and then supplied to an error correction circuit 10. The error correction circuit 10 performs an error correction process according to, for example, the RS-PC method while using the buffer memory 11 as a work area. The error-corrected binarized data is transferred to the data interface 12. The data interface 12 is provided for communication with an external information processing device such as a host computer 40 connected via the external data bus 18, and has the binary data ( (Reproduced data) to the host computer 40.

The system controller 13 controls the entire disk drive and is constituted by a microcomputer. The system controller 13 controls the operation of each unit based on the operation status, instructions from the host computer 40, and the like.

Further, a RAM block 14 is provided corresponding to the reproduction of the DVD-RAM. Where RA
The header detector 15 included in the M block 14 detects the timing at which the trace position of the laser beam passes through the header area of the DVD-RAM. Further, the PID detection unit 16 detects a physical address PID recorded in the header area.

Further, the land / groove detecting unit 17
In reproducing the information recorded in the VD-RAM, it is detected whether the recording area of the sector to be read is formed in the land or the groove, and the signal SLG is generated according to the detection result. Then, the servo processor 5 corrects the focus error signal by the focus bias value according to the supplied signal SLG.
Note that the push / pull signal PP generated in, for example, the RF amplifier 4 is supplied to the land / groove detection unit 17.

FIG. 2 is a block diagram showing a configuration of the half-track jump control circuit 70 included in the servo processor 5 shown in FIG. As shown in FIG. 2, the half track jump control circuit 70 includes a control unit 71, a jump pulse generation unit 73, a TE correction unit 75, a TCMP
It includes a signal generator 77, a track hold filter 79, a track filter 81, and a switch circuit SW.

Here, the control unit 71 is connected to the system controller 13 and the jump pulse generation unit 73
Is connected to the control unit 71. Also, the TE correction unit 7
5 is connected to the RF amplifier 4, and the track hold filter 79 and the track filter 81 are connected to the TE correction unit 75, respectively. The input end of the TCMP signal generation unit 77 is connected to the system controller 13, the TE correction unit 75, and the track hold filter 79, and the output end is connected to the control unit 71. Also, the switch circuit SW
Are connected to the jump pulse generator 73, respectively.
And the track filter 81, and the output terminal is connected to the drive circuit 6. The switching of the switch circuit SW is controlled in accordance with the signal supplied from the control unit 71.

In the half-track jump control circuit 70 having the above configuration, the optical pickup 3
Is determined by the system controller 13 to the control unit 71. The signal JD determines the jump direction, ie, forward jump or reverse jump, or land to groove jump or groove to land jump. Also, the system controller 13
Supplies a control unit 71 with a signal JS for instructing the start of the jump operation and a signal HLS for selecting which of the later-described signals TCMPH and TCMPL to use for half-track jump control, Are supplied to the TCMP signal generation unit 77.

The TE correction unit 75 corrects the tracking error signal TE supplied from the RF amplifier 4 to generate an optimized TE signal, and supplies the optimized TE signal to the TCMP signal generation unit 77, the track hold filter 79, and the track filter 81. I do. The track hold filter 79 supplies a reference value SL, which will be described later, to the TCMP signal generation unit 77, and the TCMP signal generation unit 77 supplies one of the generated signals TCMPH and TCMPL to the control unit 71. And the switch circuit SW
Supplies the optimized TE signal filtered by the track filter 81 to the drive circuit 6 as a track drive signal TD. In a half-track jump operation described in detail below, in accordance with the signal supplied from the control unit 71, The signal generated by the jump pulse generator 73 is supplied to the drive circuit 6 as a track drive signal TD.

Here, a method of generating the signals TCMPH and TCMPL by the TCMP signal generation unit 77 shown in FIG. 2 will be described with reference to FIG. First, the TCMP signal generation unit 77
As shown in FIG.
The slice level L1 supplied from the system controller 13 is set as an upper threshold value, and the slice level L2 is set as a lower threshold value, with the reference value SL supplied from 9 as an origin. Then, the TCMP signal generation unit 77
3B is monitored under the above scale, and as shown in FIG. 3B, a signal which becomes a high level (H) in a period from time T1 to time T2 exceeding the slice level L1. Generate TCMPH. Similarly, as shown in FIG. 3 (c), the TCMP signal generation unit 77 starts from time T3 when the level falls below the slice level L2 to time T
The signal TCMPL which becomes a high level (H) in the period 4 is generated.

Hereinafter, a method of controlling a half-track jump executed by the half-track jump control circuit 70 shown in FIG. 2 will be described with reference to a flowchart shown in FIG. 4 and a waveform diagram shown in FIG. explain.

First, the control unit 71 recognizes a jumping direction according to the signal JD supplied from the system controller 13. Hereinafter, a forward jump operation from a land to a groove will be described as an example. The control unit 71 selects a signal used for controlling the half-track jump operation according to the signal HLS supplied from the system controller 13. Here, the case where the signal TCMPH is selected will be described.

The control unit 71 starts a half-track jump operation in response to the signal JS supplied from the system controller 13. At this time, in step S1, the thread servo control is turned off and a forward kick is executed. Specifically, FIG.
As shown in (2), the jump pulse generator 73 generates a jump pulse having a positive voltage according to the signal supplied from the controller 71, and supplies the generated jump pulse to the switch circuit SW. The switch circuit SW includes a control unit 71
The jump pulse is supplied to the drive circuit 6 as a track drive signal TD from time T1 in accordance with the signal supplied from the drive circuit 6. Then, the drive circuit 6 responds to the high-level track drive signal TD by using the optical pickup 3.
Is moved at a predetermined acceleration from a land currently being scanned to an adjacent groove in a direction in which the radius of the optical disk 1 increases.

Next, the control section 71 executes step S
2, the signal TC supplied from the TCMP signal generation unit 77
It is monitored whether MPH is activated to a high level or not.
As shown in (b), at time T2 when the signal is activated from low level (L) to high level (H), step S2 is performed.
Proceed to 3.

In step S3, the control section 71 starts a reverse kick. That is, as shown in FIG. 5D, the jump pulse generation unit 73 generates a jump pulse having a negative voltage, and the switch circuit SW uses the jump pulse having the low level as the track drive signal TD from time T2. It is supplied to the drive circuit 6.
Accordingly, the drive circuit 6 reduces the speed of the optical pickup 3 moving toward the groove by a predetermined negative acceleration according to the track drive signal TD having the low level.

Then, in step S4, the control section 71 outputs the signal supplied from the TCMP signal generation section 77.
Monitors whether TCMPH has been deactivated to low level,
As shown in FIG. 5B, the process proceeds to step S5 at time T3 when the signal is inactivated from the high level (H) to the low level (L).

In step S5, the control section 71 recognizes the end of the half-track jump operation, and
As shown in (d), the track drive signal TD is set to 0.
Level, and the optical pickup 3 lands on the center of the desired groove. Then, the control unit 71 causes the switch circuit SW to output the optimized TE signal filtered by the track filter 81 as the track drive signal TD. Thus, the track servo control and the thread servo control are continued by the optimized TE signal generated by the RF amplifier 4 and corrected by the TE correction unit 75.

The direction of the half-track jump is specified by the signals JD and HLS supplied from the system controller 13 to the control unit 71 to the direction toward the center of the optical disk 1, and is used as a signal used in the half-track jump control. FIG. 6 shows an example in which the signal TCMPL is selected.

That is, as shown in FIG.
The optical pickup 3 causes the optical disc 1 to be driven by the track drive signal TD which has been set to a negative voltage at time T1.
Is moved (reverse kick) at a predetermined acceleration in the center direction. Then, at time T2 when the optimized TE signal falls below the slice level L2, the track drive signal TD transits to a positive voltage in response to the signal TCMPL activated to a high level, and the moving speed of the optical pickup 3 becomes a predetermined speed. Decreased by negative acceleration (forward kick). Here, the time T3 when the signal TCMPL is inactivated to low level
, The track drive signal TD is set to the 0 level,
Optical pickup 3 for the half track jump
Is stopped.

As described above, according to the disk drive device of the embodiment of the present invention, the moving speed of the optical pickup 3 is set to a predetermined negative value during a predetermined period including the peak of the tracking error signal TE generated by the RF amplifier 4. By reducing the acceleration, the optical pickup 3 can be accurately moved from the land to the adjacent groove or from the groove to the adjacent land.

Further, according to the disk drive of the embodiment of the present invention, the track drive signal TD is R
Tracking error signal T generated by F amplifier 4
Since the optical pickup 3 is generated in accordance with E and the track drive signal TD is used to control the optical pickup 3, it is not necessary to supply a necessary constant from an external device such as a microcomputer in controlling the half track jump. Control can be performed.

From the above, according to the disk drive device of the embodiment of the present invention, the load on the system controller 13 in the half-track jump control can be reduced, so that the information reproducing speed of the entire device can be increased. In addition, the circuit scale can be reduced.

[0037]

According to the disk drive apparatus and the information reading method of the present invention, the scanning position of the reading means can be automatically and accurately moved by using the tracking error signal, so that the reliability is improved. A high information reading operation can be easily realized.

A pulse signal which is activated while the tracking error signal exceeds a predetermined threshold value, and when the pulse signal is activated, the moving speed of the reading means is negatively accelerated. If the scanning position of the reading means is changed to a desired land or groove adjacent thereto, the reading means can be changed from a land to a groove adjacent to the land or from a groove to a land adjacent to the groove by a simple configuration and method. Can be accurately changed.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a configuration of a half-track jump control circuit included in the servo processor shown in FIG.

FIG. 3 shows a signal TCMP by a TCMP signal generator shown in FIG. 2;
FIG. 9 is a waveform diagram illustrating a method of generating H, TCMPL.

FIG. 4 is a flowchart showing a control method by a half-track jump control circuit shown in FIG. 2;

5 is a waveform diagram illustrating a control operation according to a signal TCMPH by a half-track jump control circuit shown in FIG. 2;

6 is a waveform chart illustrating a control operation according to a signal TCMPL by a half-track jump control circuit shown in FIG. 2;

[Explanation of symbols]

1 optical disk, 2 spindle motor (SPM),
Reference Signs List 3 optical pickup, 3a biaxial mechanism, 4 RF amplifier, 5 servo processor, 6 drive circuit, 7 binarization circuit, 8 clock reproduction circuit, 9 decoding circuit, 10
Error correction circuit, 11 buffer memory, 12 data interface, 13 system controller, 14
RAM block, 15 header detector, 16 PI
D detector, 17 land / groove detector, 18 external data bus, 19 thread mechanism, 30 laser diode, 34 objective lens, 37 photodetector, 4
0 host computer, 70 half track jump control circuit, 71 control section, 73 jump pulse generation section, 75 TE correction section, 77 TCMP signal generation section,
79 track hold filter, 81 track filter, SW switch circuit.

Continued on the front page (72) Inventor Kazuyuki Hayashi 134 Kobe-cho, Hodogaya-ku, Yokohama-shi, Kanagawa Prefecture Sony LSI Design Inc. F-term (reference) 5D117 AA02 CC06 EE09 EE24 FF24 FF14 FF18

Claims (5)

[Claims] 1. A disk drive device in which lands and grooves are alternately formed in a radial direction, and said information is read from a recording medium having information recorded on said lands and grooves by scanning by reading means, said reading means. A tracking error signal generating unit that generates a tracking error signal indicating a deviation of the scanning position, and a moving speed of the reading unit is reduced at a predetermined acceleration during a predetermined period including a time when the tracking error signal takes an extreme value. And a half-track jump control means for changing a scanning position of the reading means between the adjacent land and the groove. 2. A disk drive device in which lands and grooves are formed alternately in a radial direction, and the information is read by scanning by a reading unit from a recording medium on which information is recorded on the lands and the groove, wherein the reading unit A tracking error signal generating unit that generates a tracking error signal indicating a deviation of the scanning position, and a pulse signal generating unit that generates a pulse signal that is activated while the tracking error signal exceeds a predetermined threshold. The scanning position of the reading means is accelerated by moving the reading means to the adjacent land or groove, and the moving speed of the reading means is negatively accelerated when the pulse signal is activated. And a half track jump control means for changing the desired land or the adjacent groove. A disk drive device comprising: 3. The method according to claim 2, wherein the pulse signal generating unit is configured to activate a first pulse signal activated when the tracking error signal becomes larger than a first threshold value and to generate a second pulse signal when the tracking error signal is equal to a second threshold value. A second pulse signal that is activated when the value becomes smaller than a threshold value, and the half-track jump control unit generates one of the first pulse signal and the second pulse signal. 3. The disk drive device according to claim 2, wherein one of them is selected, and the movement of said reading unit is controlled in accordance with the selected first pulse signal or second pulse signal. 4. An information reading method in which lands and grooves are alternately formed in a radial direction, and the information is read from a recording medium having information recorded on the lands and grooves by scanning by a reading unit. Generating a tracking error signal indicating a deviation of the scanning position, and, during a predetermined period including a time at which the tracking error signal takes an extreme value, reducing a moving speed of the reading unit by a predetermined acceleration, thereby forming an adjacent scanning error signal. Changing the scanning position of the reading means between the land and the groove. 5. An information reading method in which lands and grooves are alternately formed in a radial direction, and the information is read from a recording medium having information recorded on the lands and grooves by scanning by a reading unit. Generating a tracking error signal indicating the deviation of the scanning position, generating a pulse signal activated while the tracking error signal exceeds a predetermined threshold value, and accelerating the reading unit. Moving the scanning position of the reading means to the adjacent desired land or groove by negatively accelerating the moving speed of the reading means when the pulse signal is activated. Changing to a land or the groove.