KR100713373B1 - Tracking servo regulating method for optical disc reproducing apparatus - Google Patents

Abstract

The present invention provides a tracking servo adjustment method for an optical disc apparatus, by detecting a track pitch difference between an inner circumference and an outer circumference of an optical disc so that the tracking error servo coefficient in the outer circumferential region can be appropriately adjusted based on the detected track pitch difference value. To provide. To this end, the present invention is to detect the track pitch difference value between the inner and outer circumference of the optical disk in the track off state, and to determine the outer circumferential section to adjust the tracking error servo coefficient based on the detected track pitch difference value And adjusting the tracking error servo coefficient if the area for reading data in the on-track state corresponds to an outer circumferential section requiring adjustment of the tracking error servo coefficient.

Optical disc, track, tracking error signal, sensitivity, tracking error servo coefficient

Description

TRACKING SERVO REGULATING METHOD FOR OPTICAL DISC REPRODUCING APPARATUS}

1 is a view showing the configuration of an optical disk apparatus to which the tracking servo adjustment method according to the present invention is applied;

2 is a diagram illustrating track pitch detection states of the inner and outermost circumferences of an optical disc in a track off state according to the present invention;

3 is a view showing a state in which the outermost track pitch is detected across a track of an optical disc according to the present invention;

4 is a view showing a state in which an adjustment section of a tracking error servo coefficient at an outer circumference is set by a difference in the triangular waveform slope between the inner and outer circumferences of an optical disc according to the present invention;

5 is a diagram illustrating a tracking servo control configuration for adjusting tracking error servo coefficients according to the present invention;

6 is a flowchart for explaining the operation of the tracking servo adjustment method of the optical disk apparatus according to the present invention.

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

10: optical disc, 20: optical pickup,

30a: digital recording signal processing section, 30b: digital reproduction signal processing section,

40: channel bit encoder, 41: optical driver,

50: RF signal processing unit, 60: servo unit,

61: servo drive unit, 63: tracking servo drive unit,

64: focusing servo drive unit, 80: microcomputer,

81: memory.

The present invention relates to a tracking servo adjustment method of an optical disc device, and more particularly, to a tracking servo adjustment method of an optical disc device that detects a difference in track pitch of an inner and outer circumference of an optical disc to adjust a sensitivity of a tracking error signal. .

Typically, a Digital Versatile Disc Read Only Memory (DVD-ROM) or a Rewritable Digital Versatile Disc (DVD-RW, DVD-RAM), a recordable digital versatile disc (Recordable) In the case of playing a digital versatile disc (DVD) such as a Digital Versatile Disc (DVD-R) through an optical disc device, a tracking control signal is generated for tracking control.

There are three beam methods, a push pull method, and a differential phase detection (DPD) method for generating a tracking error signal in the digital multifunction disk. A pair of tracking side beam spots are arranged before and after the main beam spot for reading information, and the main light detecting element detecting the light amount of the main beam and the light amount of the side beam are detected. The tracking error signal is generated through the side photodetector.

In the case of the push-pull method, a photodetector for detecting the reflected light from the digital multifunction disk is divided into two along the track direction of the disk, and arranged back and forth with respect to the four divided photodetectors. It is used to detect a tracking error signal from the device in which the intensity distribution of light diffracted and reflected by the track pit and incident through the objective lens is changed by the relative positional change between the pit and the light spot.

In addition, in the case of the phase difference detection method, the light intensity distribution according to the relative positional change of the light beam and the track fit of the disk is used by using the photodetection element divided into four, and thus the signal track direction (that is, the tangential Directions) and four photodetectors divided into four directions in the radial direction are arranged to detect a phase error of an electrical signal according to the amount of light obtained from each photodetector so as to obtain a tracking error signal. It is possible to determine the signal sensitivity of the tracking error signal in consideration of the track pitch for the Groove track.

However, in the method of generating the tracking error signal in the optical disc device, the sensitivity of the tracking error signal can be determined in consideration of the track pitch of the groove track of the optical disc. However, when the track pitch between the inner and outer circumferences of the optical disc is different. In this case, since the magnitude of the tracking error may be different because the degree of interference by the adjacent tracks is different, there is a problem in that accurate tracking error servo cannot be performed for the entire track of the optical disc while the tracking accuracy decreases.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to detect a track pitch difference between an inner circumference and an outer circumference of an optical disc, thereby tracking in an outer circumferential region based on the detected track pitch difference value. It is to provide a tracking servo adjustment method of an optical disk device that can adjust an error servo coefficient appropriately.

According to the present invention for achieving the above object, detecting a track pitch difference value between the inner circumference and the outer circumference of the optical disc in the track off state, and adjusting the tracking error servo coefficient based on the detected track pitch difference value Identifying the necessary outer circumferential section, and if the area for reading data in the on-track state corresponds to the outer circumferential section requiring adjustment of the tracking error servo coefficient, adjusting the tracking error servo coefficient. A tracking servo adjustment method for an optical disk device is provided.

Hereinafter, the present invention configured as described above will be described in detail with reference to the accompanying drawings.

That is, FIG. 1 is a diagram showing the configuration of an optical disk apparatus to which the tracking servo adjustment method according to the present invention is applied.

As shown in Fig. 1, the optical disk apparatus according to the present invention is an optical disk 10 that irradiates a laser beam of a predetermined recording power to the optical disk 10 to record data or to read a signal recorded on the optical disk 10 from the reflected light of the laser light. The pickup 20, a digital recording signal processor 30a for adding an error correction code (ECC) to the input digital data, and converting the binary signal reproduced from the optical disc 10 into an original video / A digital reproduction signal processor 30b for restoring and outputting the audio data, a channel bit encoder 40 for reconverting the data converted into the recordable format into a bit stream, and optically driving the light quantity driving signal according to the bit stream signal. 20) filter the signals from the optical driver 41 and the optical disk 10 read out from the optical pickup 20, and output them as binary signals. Focusing / tracking servo of the optical pickup 20 and rotational drive of the optical disc 10 by the RF signal processing unit 50, the focusing error signal FE and the tracking error signal TE from the optical pickup 20. The servo unit 60 for controlling the control, the servo driver 61 for controlling the rotation of the spindle motor 62 by the servo operation of the servo unit 60, the tracking servo control of the servo unit 60 A tracking servo driver 63 for driving the tracking servo of the pickup 20 and a focusing servo driver for driving the focusing servo of the optical pickup 20 according to the focusing servo control of the servo 60. (64) A servo for adjusting the signal sensitivity of the tracking error signal from the specific outer peripheral region of the optical disk 10 through the track pitch difference by detecting the track pitch difference at the inner and outermost circumferences of the optical disk 10. FIG. Servo unit 60 to control And a memory 81 composed of a non-volatile memory such as EEPROM in which a tracking error servo coefficient value determined by a tracking error servo in the inner circumference of the optical disc 10 is stored as a reference value. .

As shown in FIG. 2, the servo unit 60 converts the track pitch of the groove track with respect to the inner circumference of the optical disc 10 in a track off state to an inclination value represented by a triangular waveform, and the inner circumference thereof. The slope k1 is set to the reference slope (that is, k1 / k1 = 1), and the slope k2 for the triangular waveform of the track pitch with respect to the outermost circumference of the optical disc 10 is detected, and the outermost slope is By comparing (k2) with respect to the slope of the inner circumference (ie k2 / k1 = x), the track pitch difference between the inner circumference and the outer circumference is detected.

That is, as shown in FIG. 4, a tracking error servo coefficient is set based on the track pitch of the inner circumference of the optical disc 10 and stored as a reference value in the memory 81, and then the disk is traversed in the track off state. The track pitch at the outermost circumference of the optical disc 10 is detected as the inclination value in the triangular waveform.

When the tilt value of the triangular waveform according to the track pitch at the outermost circumference of the optical disc 10 is detected, as shown in FIG. 4, the value of the slope k1 at the inner circumference is compared with the value of the outermost slope k2. The inclination difference value (e.g., k2 / k1 = 1.05) is detected, and the difference value indicates that a predetermined outer circumferential section (e.g., inclination ratio differs by more than "A") of the optical disc 10 that requires adjustment of the tracking error servo coefficient. Area).

In the present invention illustrated in FIG. 4, only the case where the track pitch becomes narrower toward the outer periphery of the optical disc is described, but the track pitch may be wider from the inner periphery of the optical disc to the outer periphery. On the contrary, the graph indicating the slope ratio decreases from the inner circumference to the outer circumference, and it is preferable to increase the sensitivity of the tracking error signal toward the outer circumference.

Subsequently, in the state where the data recorded on the optical disc 10 is reproduced (tracking is performed), the disc area read by the optical pickup 20 by irradiating a laser beam is required to adjust the tracking error servo coefficient. In the case of the section, the tracking error servo coefficient is adjusted based on the tracking error servo coefficient at the preset inner circumference in consideration of the inclination value due to the difference in track pitch from the section to the outermost circumference.

As shown in FIG. 5, in the state in which the tracking error signal TE from the optical pickup 20 is amplified and input through the amplifier 65, the tracking error signal is received by the servo unit 60. If (TE) is a signal generated in an outer circumferential section requiring adjustment of the framing error servo coefficient, the signal sensitivity of the tracking error signal TE can be lowered to a specific value by adjusting the gain value of the amplifier 65. The tracking error servo coefficient for the tracking servo drive of the tracking servo driver 63 is adjusted.

Next, FIG. 6 is a flowchart for explaining the operation of the tracking servo adjustment method of the optical disk apparatus according to the present invention.

Hereinafter, the flowchart according to the embodiment of the present invention shown in FIG. 6 will be described in detail in parallel with the operation of the apparatus of FIG. 2.

First, when the optical disc 10 is mounted, the optical pickup 20 detects the track pitch in the inner circumference of the optical disc 10 in the track off state (step S10), and the inclination value of the triangular waveform according to the track pitch. In consideration of this, by setting the tracking error servo coefficient to a reference value, the tracking error servo coefficient to be the reference value is stored in the memory 81 (step S11).

In this state, as shown in FIG. 4, the track pitch of the outermost circumference is detected by crossing the track of the optical disc 10 in the optical pickup 20 (step S12), and the inner and outer circumferences of the optical disc 10 are detected. The track pitch difference value therebetween is detected by comparing the slope k1 value of the triangular waveform of the inner circumference with the slope k2 value of the triangular waveform at the outermost circumference (step S13).

When a track pitch difference value between the inner circumference and the outer circumference of the optical disc 10 is detected, as shown in FIG. 4, an outer circumferential region requiring adjustment of a tracking error servo coefficient according to the detected track pitch difference value (ie, Area where the tilt ratio becomes "A".

On the other hand, when the reproduction operation of the data recorded on the optical disc 10 is started (step S14), the track section read by the optical pickup 20 for reproduction of the data is an outer peripheral area that requires adjustment of the tracking error servo coefficient. In step S15, if it is determined that the section for reading data from the optical pickup 20 is the coefficient adjustment section, as shown in FIG. 5, the tracking error signal TE is determined. By adjusting the gain value of the amplifier 65 for amplifying the signal, the signal sensitivity of the tracking error signal TE can be lowered, so that the tracking error servo coefficient for the tracking error servo is adjusted (step S16). For example, if the tilt ratio becomes larger than "A", this means that the track pitch is narrowed and can be further affected by adjacent tracks, so that the servo coefficient, or gain factor, can be lowered to reduce the sensitivity of the tracking error signal. do.

Then, it is determined whether the reproducing operation of the disc 10 continues (step S17), and if it is determined that the reproducing of the optical disc 10 is continuously performed, the operation of step S16 is repeatedly performed in step S14. When it is determined that the reproduction operation of the optical disc 10 is finished, the setting value of the tracking error servo coefficient is initialized (step S18).

On the other hand, the present invention is not limited to the above-described typical preferred embodiments, but can be carried out in various ways without departing from the gist of the present invention, various modifications, alterations, substitutions or additions are common in the art Those who have knowledge will easily understand. If the implementation by such improvement, change, replacement or addition falls within the scope of the appended claims, the technical idea should also be regarded as belonging to the present invention.

As described above, according to the present invention, the track pitch difference value between the inner circumference and the outer circumference of the optical disc is detected in the track-off state in the optical disk device, and the outer circumferential section requiring adjustment of the tracking error servo coefficient is identified according to the detected difference value. When the optical disc reaches a peripheral section that requires adjustment of the tracking error servo coefficients, the tracking error servo coefficients can be adjusted by lowering the signal sensitivity of the tracking error signal. In addition to minimizing the influence of adjacent tracks caused by the difference in track pitch, the optimum tracking error servo function is possible.

Claims (4)

Detecting a track pitch difference value between an inner circumference and an outer circumference of the optical disc in the track-off state; A second step of identifying a peripheral section requiring adjustment of a tracking error servo coefficient based on the detected track pitch difference value; And If the area for reading data in the on-track state corresponds to an outer section requiring adjustment of the tracking error servo coefficient, the tracking servo adjustment of the optical disc device, characterized in that the third step of adjusting the tracking error servo coefficient is performed. Way. The method of claim 1, In the first step, the track pitch of the optical disc inner circumference is determined as an inclination value for a triangular waveform detected by a phase difference detection method, and the tracking error servo coefficient for the inclination value is set as a reference value. , Detecting a track pitch at the outermost circumference across the track of the optical disc as a slope value for the triangular waveform; And detecting a track pitch difference value between an inner circumference and an outermost circumference of the optical disc as the inclination difference value between the inner circumference and the outer circumference. The method according to claim 1 or 2, The third step is a tracking servo adjustment method of the optical disk device, characterized in that for adjusting the tracking error servo coefficient of the outer peripheral section on the basis of the tracking error servo coefficient set to the reference value in the inner circumference of the optical disk. The method of claim 3, wherein The third step is to adjust the tracking error servo coefficients by adjusting the gain value of the amplifier (Amp) to amplify the tracking error signal to lower or increase the signal sensitivity of the tracking error signal. Tracking servo adjustment method.

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