KR20060068655A - Method for tilt control in optical recorder - Google Patents

Abstract

The present invention relates to a tilt control method of an optical recorder, and if the optical disc is recognized, extracting a unique code of the optical disc and checking whether there is tilt control information corresponding to the extracted unique code among previously stored tilt information; When the tilt control information corresponding to the extracted unique code does not exist, after performing the tilt servo control according to the known tilt control process according to the type of the optical disc, the extracted unique code and each region of the corresponding disc Storing the tilt control information for each star; and performing tilt servo control based on previously stored tilt control information when there is tilt control information corresponding to the extracted unique code. Save the tilt control information for each area of the disk and save the By performing the tilt control based on the stored tilt control information, there is an advantage that the loading time of the optical disc can be minimized and the load of the optical pickup portion can be reduced.

Description

Tilt control method of optical recorder {METHOD FOR TILT CONTROL IN OPTICAL RECORDER}

1 is a block diagram of a general optical recorder;

2 is a flowchart illustrating a tilt control process of an optical recorder according to the prior art;

3 is a block diagram of an optical recorder to which the tilt control method according to the present invention can be applied;

4A and 4B are flowcharts illustrating a tilt control process according to the present invention.

<Explanation of symbols for the main parts of the drawings>

11 optical disc 12 optical pickup

13 RF and Servo Error Generator 14 Focus Servo Driver

15 control unit 16 tracking servo drive unit

17: tilt drive unit 100: disk tilt information storage unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt control method of an optical recorder, and more particularly, to a tilt servo for controlling a tilt component between an optical disk recording surface and an objective lens in an optical pickup generated due to the bending of the optical disk.

In general, laser data is incident on the opposite side of a reflective surface having a pit in recording and reproducing data on a recordable optical recording medium, i.e., an optical disc. Therefore, in terms of laser incidence, the pit appears as a projection.

Such an optical disk may be warped during the injection and curing of the resin in the manufacturing process, and this may cause an eccentricity even when a central hole is drilled. Further, even if the disc track is accurately recorded in a spiral shape at a pitch of a predetermined standard, an eccentricity is generated because the center hole is varied. Thus, the disk rotates with eccentricity, so it is difficult for the central axis of the motor and the center of these tracks to completely coincide.

For this reason, since it is difficult to read exactly the signal of the desired track accurately, the CD and DVD systems set the standard for this misalignment amount, and tracking servo is performed so that the light beam can follow the desired track even if such eccentricity occurs.

That is, the tracking server generates an electrical signal corresponding to the beam trace state and based on the signal, moves the objective lens or the optical pickup main body in the radial direction to correct the position of the beam so that the track can be accurately followed.

On the other hand, when the beam deviates from the track, not only the eccentricity of the disc but also the case where the disc is inclined. This may occur due to mechanical problems such as an error in mounting the disk to the spindle motor. That is, the focusing and tracking do not exactly match vertically, but are distorted. The tilted state of the disc is called tilt.

This tilt was not a big problem for CDs with large track pitches because of their wide track pitch. Here, the tilt margin is an amount that can be corrected even if the disk is inclined to some extent. However, in DVDs where optical pitches such as optical discs have become larger and more dense, the track pitch narrows, the radial tilt margin for jitter is small, so that even if a little tilt occurs, i.e., even if the disc is tilted slightly, the beam will move to the next track. Detrack occurs, but tracking servo alone is not enough. That is, even if the beam is moved to the next track by tilt, if the beam is in the center of the track, the tracking servo can determine that the track is accurately tracked.

In this case, data cannot be read correctly during reproduction, and since the data cannot be recorded accurately on the track during recording, double distortion occurs when the recorded data is reproduced.

FIG. 1 is a block diagram of a general optical recorder, in which laser light emitted from a laser diode of the optical pickup unit 12 is mounted on a drive, or the optical disk 11 rotates during recording / reproducing. Overlying the signal track, the reflected light is incident on the photo detector.

The photo detector consists of a plurality of photo detectors, and an electrical signal proportional to the amount of light obtained from each photo detector is output to the RF and servo error generator 13.

The RF and servo error generator 13 combines the electrical signals output from the respective optical detection elements to generate an RF signal for data reproduction, a tracking error signal TE for servo control, a focus error signal FE, and the like. To the control unit 15.

The controller 15 processes the focus error signal FE to output a drive signal for focusing control to the focus servo driver 14, and processes the tracking error signal TE to track the drive signal for tracking control. Output to the servo driver 16.

The focus servo driver 14 moves the optical pickup 12 up and down by driving the focus actuator in the optical pickup 12 so that the optical disk 11 follows the vertical movement along with the rotation. That is, the focus actuator for driving the focused objective lens up and down, that is, in the focus axis direction, keeps the distance between the objective lens and the optical disc 11 constant according to the focus control signal.

The tracking servo driver 16 drives the tracking actuator in the optical pickup section 12 to move the objective lens of the optical pickup section 12 in the radial direction to correct the position of the beam and follow a predetermined track.

In addition, when the optical disk is inserted into the drive, the controller 15 adjusts the tilt through the tilt driver 17 for each designated tilt adjustment position.

On the other hand, the tilt adjustment performed by the tilt driver 17 is controlled according to the type of the optical disc 11. When the optical disk 11 is a blank disk that can be recorded, the controller 15 performs tilt control through the tilt driver 17 by using a push-pull signal, and the other disks use the jitter value of the RF signal. The tilt control is performed by using the tilt driver 17.

Here, the push-pull signal is a tracking error signal TE detected by the push-pull method, and splits the reflected light from the optical disk 11 and compares the respective intensities. That is, when the laser beam is irradiated to the pit, diffraction occurs. In the correct tracking state, the left and right diffraction light is symmetrical about the optical axis. When the reflected light is detected by the two-segment photodetector in the optical pickup section 12, the output difference is detected as zero. In other words, the push-pull signal becomes zero. However, if the spot deviates to the left with respect to the pit, the diffraction effect of the laser light incident on the left side of the pit decreases, and the diffraction light becomes asymmetrical to detect a push-pull signal in which the reflected light on the left side increases. On the contrary, if the signal deviates to the right side, a push pull signal in which the right side increases is detected.

Referring to Figure 2 will be described in more detail the tilt control process according to the prior art.

First, when the optical disk 11 is inserted into the drive, the control unit 15 recognizes the type of the optical disk (S31, S33).

As a result of the recognition, when the optical disk 11 is a blank disk which can be recorded, the recording area of the optical disk 11 is equally divided into N areas (S51), and the push-pull signal according to the tilt change in each area is measured. do. That is, the tracking error signal TE output from the push-pull amplifier in the RF and servo error generation unit 13 is measured while going from the inner circumference of the optical disk 11 to the outer circumference (S53).

Here, an optimal tilt offset value in which the push-pull signal is maximized in each area is set (S55).

As a result of the recognition in step S33, when the optical disc 11 is not a recordable blank disc, the recording area of the optical disc 11 is equally divided into N areas (S41), and the RF signal according to the tilt change in each area. The jitter amount of the (playback signal) waveform is measured (S43).

Here, an optimal tilt offset value in which jitter of the RF signal is minimized in each region is set (S45).

After performing step S45 or S55, the sections having similar tilt values are regrouped to group the N regions into M groups (S61), and the optimal tilt servo operation is performed using the tilt control values of the M groups grouped into M regions. In step S63, data is read from or written to the optical disc 11 (S65).

However, according to the conventional tilt control method as described above, the loading time of the optical disc is adversely affected by performing the process of dividing the tilt area every time an optical disc is inserted and obtaining an optimal value thereof. There was a problem of providing a high load to the wealth.

The present invention has been proposed to solve such a conventional problem, and after performing the tilt control process, the tilt control information for each region of the corresponding disk is stored, and then the same disk is controlled based on the previously stored tilt control information. By doing this, the object is to minimize the loading time of the optical disc and reduce the load of the optical pickup.

It is another object of the present invention to improve tilt servo performance by performing tilt servo by resetting tilt information using jitter values after test recording based on previously stored tilt control information for a recordable blank disc.

In the tilt control method of the optical recorder according to the present invention for realizing the above object, if the optical disc is recognized, there is a tilt control information corresponding to the extracted unique code from the stored tilt information after extracting the unique code of the optical disc The step of checking whether or not the tilt control information corresponding to the extracted unique code does not exist, and after performing the tilt servo control according to a known tilt control process according to the type of optical disk, the extracted unique code and the corresponding code Storing tilt control information for each region of the corresponding disk; and performing tilt servo control based on previously stored tilt control information when there is tilt control information corresponding to the extracted unique code.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. This embodiment allows for a better understanding of the objects, features and advantages of the present invention. However, the present invention is not limited to this embodiment.

FIG. 3 is a block diagram of an optical recorder to which the tilt control method according to the present invention can be applied. Like reference numerals denote like elements when compared with the conventional optical recorder shown in FIG.

The laser light emitted from the laser diode of the optical pickup unit 12 while the optical disk 11 is mounted in the drive or during recording / reproducing is placed on the signal track of the rotating optical disk 11, where the reflected light is the optical detector Incident.

The photo detector consists of a plurality of photo detectors, and an electrical signal proportional to the amount of light obtained from each photo detector is output to the RF and servo error generator 13.

The RF and servo error generation unit 13 combines the electrical signals output from the respective optical detection elements to generate an RF signal for data reproduction, a tracking error signal TE for servo control, a focus error signal FE, and the like. To the control unit 15.

The controller 15 processes the focus error signal FE to output a drive signal for focusing control to the focus servo driver 14, and processes the tracking error signal TE to track the drive signal for tracking control. Output to the servo driver 16.

The focus servo driver 14 moves the optical pickup 12 up and down by driving the focus actuator in the optical pickup 12 so that the optical disk 11 follows the vertical movement along with the rotation. That is, the focus actuator for driving the focused objective lens up and down, that is, in the focus axis direction, keeps the distance between the objective lens and the optical disc 11 constant according to the focus control signal.

The tracking servo driver 16 drives the tracking actuator in the optical pickup section 12 to move the objective lens of the optical pickup section 12 in the radial direction to correct the position of the beam and follow a predetermined track.

In addition, when the optical disk is inserted into the drive, the controller 15 adjusts the tilt through the tilt driver 17 for each designated tilt adjustment position.

The tilt adjustment performed by the tilt driver 17 varies its control depending on the type of the optical disc 11. The process in which the controller 15 performs the tilt control through the tilt driver 17 will be described again with reference to FIGS. 4A and 4B.

On the other hand, the controller 15 stores the tilt control information for each area of the disk in the disk tilt information storage unit 100 after performing the tilt control process, and then stores the same disk based on the previously stored tilt control information. Perform tilt control. The disc-specific tilt information storage unit 100 may use an EEPROM provided in the optical pickup unit.

4A and 4B are flowcharts illustrating a tilt control process according to the present invention.

As described above, when the optical disc is recognized, the tilt control method of the present invention includes extracting a unique code of the optical disc, and then checking whether there is tilt control information corresponding to the extracted unique code among previously stored tilt information. S211 to S215), and when there is no tilt control information corresponding to the extracted unique code, after performing the tilt servo control according to a known tilt control process according to the type of the optical disk, the extracted unique code and the corresponding code The second step (S231 to S243) for storing the tilt control information for each region of the disk, and the tilt servo control based on the previously stored tilt control information when there is a tilt control information corresponding to the extracted unique code The third step (S221 to S263, S215 to S253) is included. Thereafter, in step S271, data is read or recorded from the optical disc 11 in the second or third step.

The second step includes the step of determining the type of the optical disc (S231), the step of equally dividing the recording area of the optical disc into N areas (S233), and each area when the optical disc is a recordable blank disc. Measuring the push-pull signal according to the tilt change in the step of measuring the jitter amount of the reproduction signal waveform according to the tilt change in each region (S235), and the push-pull signal in each region is the maximum Setting the optimum tilt offset value at which the jitter of the playback signal is minimized or the reproduction signal is minimized (S237), grouping N regions into M groups by regrouping sections having similar tilt values (S239), and by M Performing an optimal tilt servo operation using the tilt control values of the grouped regions (S241), and storing tilt control information for each region of the corresponding disk together with the unique code of the optical disk (S243). ).

The third step is to determine the type of optical disc (S221), and if the optical disc is not a recordable blank disc, read tilt control information corresponding to the extracted unique code and extract it from each region grouped into M pieces. Performing a tilt servo operation based on the obtained tilt control information (S261, S263); if the optical disk is a recordable blank disk, reading the tilt control information corresponding to the extracted unique code (S251); Based on the tilt control information extracted from each M grouped area, random test recording is performed in the recording test section of the relevant area, and then the tilt servo operation is redefined by minimizing the tilt servo value that minimizes the jitter by the test recording. A step S253 is performed.

The process performed by the tilt control method according to the present invention configured as described above in the optical recorder of FIG. 3 will be described in detail below with reference to FIGS. 3, 4A, and 4B.

First, when the optical disk 11 is inserted into the drive, the control unit 15 extracts a unique code (disc volume ID) included in the control data of the optical disk 11 (S211). The tilt information stored in the tilt information storage unit 100 is searched (S213) to check whether there is tilt control information corresponding to the extracted unique code (S215). Here, the pre-stored tilt information means tilt control information for each area of the corresponding disk stored in step S243 which will be described later.

If it is determined in step S215 that there is no tilt control information corresponding to the extracted unique code, the tilt servo control is performed according to a known tilt control process according to the type of the optical disc 11.

This known tilt control process determines whether the optical disc 11 is a recordable blank disc (S231), divides the recording area of the optical disc 11 into N areas (S233), and writes a blank disc. In one case, the push-pull signal according to the tilt change in each region is measured, and in the case of other discs, the jitter amount of the reproduced signal waveform according to the tilt change in each region is measured (S235). Subsequently, an optimal tilt offset value in which the push-pull signal is maximized or the jitter of the reproduction signal is minimized is set in each region (S237), and the N regions are grouped into M by regrouping sections having similar tilt values. In operation S239, an optimal tilt servo operation is performed using the tilt control values of each of the M groups.

At this time, the tilt control information (group tilt area address, tilt value, etc.) for each region of the disk along with the unique code of the optical disk 11 is stored in the tilt information storage unit 100 for each disk (S243).

Then, data is read from or written to the disk 11 while the tilt servo operation is performed (S271).

On the other hand, if it is determined that the tilt control information corresponding to the extracted unique code is present in the tilt information storage unit 100 for each disc, the type of the optical disc 11 is again determined (S221).

If the optical disc 11 is not a recordable blank disc, the tilt control information corresponding to the unique code extracted in step S211 is read from the disc-specific tilt information storage unit 100 (S261) and grouped into M pieces. The tilt servo operation is performed based on the tilt control information extracted from each region (S263).

If the optical disc 11 is a recordable blank disc as a result of the determination in step S221, the tilt control information corresponding to the unique code extracted in step S211 is read from the disc-specific tilt information storage unit 100 (S251). Based on the tilt control information extracted from each of the M grouped areas, arbitrary test recording is performed in a recording test section of the corresponding area, that is, a power calibration area (PCA).

Then, the test section is read and the tilt servo value at which the jitter amount of the reproduction signal waveform is minimized is redefined, and the tilt servo operation is performed based on the redefined tilt servo value (S253).

Finally, while performing the tilt servo operation as in step S253 or S263, data is read from or written to the disk 11 (S271).

In the foregoing description of the present invention, only one embodiment has been described, but it is obvious that the technology of the present invention can be easily modified by those skilled in the art. Such modified embodiments should be included in the technical spirit described in the claims of the present invention.

As described above, the present invention stores the tilt control information for each region of the disc after the tilt control process, and then performs the tilt control on the basis of the previously stored tilt control information for the same disc, thereby loading the optical disc. The time can be minimized and the load of the optical pickup portion can be reduced.

Further, the tilt servo performance is improved by performing tilt servo by re-defining the tilt information using the jitter value after the test recording on the basis of the previously stored tilt control information for the recordable blank disk.

Claims (4)

A first step of extracting a unique code of the optical disc after the optical disc is recognized and checking whether there is tilt control information corresponding to the extracted unique code among pre-stored tilt information; If there is no tilt control information corresponding to the extracted unique code, after performing the tilt servo control according to a known tilt control process according to the type of the optical disc, the extracted unique code and the corresponding disc A second step of storing the tilt control information for each region; A third step of performing tilt servo control based on previously stored tilt control information when there is tilt control information corresponding to the extracted unique code; Tilt control method of the optical recorder comprising a. The method of claim 1, The unique code of the optical disk is a disk volume ID Tilt control method of an optical recorder characterized in that. The method of claim 1, The second step, Determining a type of the optical disc; Dividing the recording area of the optical disk into N areas equally; As a result of the type discrimination, when the optical disc is a recordable blank disc, the push-pull signal according to the tilt change in each area is measured, and in the case of other discs, the jitter of the reproduction signal waveform according to the tilt change in each area is measured. Measuring the quantity, Setting an optimal tilt offset value at which the push-pull signal is maximum or the jitter of the reproduction signal is minimum in each area; Regrouping sections having similar tilt values based on the set tilt values to group N regions into M groups; Performing an optimal tilt servo operation using the tilt control values of each of the M groups; Storing tilt control information for each area of the disk by the tilt servo together with the unique code of the optical disk Tilt control method of the optical recorder comprising a. The method of claim 1, The third step, Determining a type of the optical disc; If the optical disc is not a recordable blank disc as a result of the type discrimination, the tilt servo is read based on the tilt control information extracted in each of the M grouped regions by reading the tilt control information corresponding to the extracted unique code. Performing an action, In the case where the optical disc is a recordable blank disc as a result of the type discrimination, the tilt control information corresponding to the extracted unique code is read and recorded in the corresponding area based on the extracted tilt control information in each of the M grouped areas. Performing a random servo operation by performing a random test recording on a test section and resetting a tilt servo value that minimizes the amount of jitter by the test recording. Tilt control method of the optical recorder comprising a.

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