KR20010080804A - Apparatus and method for controlling track search in optical disc driver - Google Patents

Abstract

PURPOSE: Controlling device and method for a track search are provided to prevent a track search error caused by eccentricity of an optical disk through completing track search at a lowest section of a track traverse signal. CONSTITUTION: A spindle motor is rotated to rotate an optical disk. A pulse signal generate unit outputs a pulse signal corresponding to one rotation of the optical disk by using a frequency signal from the spindle motor. The frequency signals are counted based on the pulse signal. Then, frequency signal values for minimum and maximum levels are stored. In a reproducing mode, number of searching tracks are checked for a target track. Then, an estimated time for track search is checked by detecting an estimating time table stored in a memory. Then, a minimum eccentricity detect unit counts the received frequency signals based on the pulse signal for calculating time of track search to a minimum eccentricity location. A timing controller compares the detected time with the estimated time to perform the track search according to identification of the values.

Description

Apparatus and method for controlling track search in optical disc driver}

The present invention relates to an apparatus and method for controlling a track search in an optical disk apparatus such that a track search operation in consideration of an eccentric component of the optical disk is performed when a track search request is made in the optical disk apparatus.

First, FIG. 1 shows a configuration of a general optical disc apparatus, which includes: an optical pickup 2 for reading out a signal from an optical disc 1 seated and inserted into a tray; A filter forming unit (3) for filtering the high frequency signal read out from the optical pickup and outputting the filtered high frequency signal as a binary signal; A digital signal processor (4) for digitally processing the binary signal and outputting the digital signal; A spindle motor 10 for rotating the optical disc 1; A sled motor (9) for horizontally moving the optical pickup; A motor driver (7) for rotationally driving the spindle motor and the sled motor; A servo unit (5) for controlling the servo operation of the optical pickup and the motor driver; A microcomputer 6 for controlling the operation of the servo unit and the digital signal processing unit; And a memory 9 for storing data necessary for the control operation of the microcomputer, wherein the servo unit 5 in the optical disk device configured as described above is provided with a laser diode (e.g., provided in the optical pickup 2). The light spot emitted from the LD is controlled to track the center of the recording track of the optical disc 1, or to perform and control a track search operation for controlling the search to move to a target track. Hereinafter, the configuration and operation of the servo unit for controlling the track search operation will be described in detail.

First, FIG. 2 shows a detailed configuration of a servo unit in a general optical disc apparatus. In particular, the configuration of the servo unit for controlling the track search operation is a square wave signal S1 of a high frequency ripple component output from the optical pickup 2. And the track crossing signal (TZC: Track Zero Crossing (S2)) and the signal S3 which latches the square wave signal (S1) at the edge of the track yellow end signal (S2) as an input signal. A track / cycle counting unit 51 for counting the period; A reference speed generator 56 which generates and outputs a reference track search speed (Ref Speed) corresponding to the track traverse number counted by the track / cycle counting unit (51); A speed calculator (52) for calculating a current track search speed based on the period of the track crossing signal calculated by the track / count unit (51); A calculator (53) for calculating the reference track search speed and the current track search speed and outputting the difference value as a track search speed error (Error); A track search controller 54 for generating and outputting a pulse for compensating the track search speed error, that is, a kick pulse for track search and a brake pulse for stopping the track search; And a D / A converter 55 for converting the kick pulse or the brake pulse output from the track search controller into a track search driving signal TDO and outputting it as a track search driving signal TDO. In the track search control operation in 5), when the track search operation is first performed in accordance with a key input signal input from a user, the track / cycle counting unit 51 receives the signals S1, S2, and S3. After receiving, after counting the number of track traverses and the period according to the current track search operation, and outputs the counted track traverses to the reference speed generator 56, the cycle of the counted track traverse signal Output to the calculation unit 52, respectively.

Accordingly, the reference speed generator 56 generates and outputs a reference track search speed corresponding to the counted number of track crossings. When the number of track crossings is large, the reference track search speed is generated with a low value. When the number of track crossings is small, the reference track search speed is generated and output as a high value, while the speed calculation unit 52 calculates the current track search speed based on the period of the track crossing signal. If the period of the track crossing signal is long, the current track search speed is calculated and outputted as a low value. If the period of the track crossing signal is short, the current track search speed is calculated and outputted as a high value. .

On the other hand, the calculator 53 subtracts the current track search speed and the reference track search speed, and outputs the difference value between the speeds as the track search speed error value, and in the track search controller 54 which receives it, To generate and output a kick pulse or a brake pulse to compensate for the track search speed error, for example, if the current track search speed is faster than the reference track search speed, to reduce the current track search speed, Since the brake pulse is output, the driving signal TDO converted by the D / A converter 55 to be output is outputted with the reverse driving signal corresponding to the brake pulse.

Therefore, as described above, the actuator of the optical pickup 2 is applied with the forward / reverse driving voltage for compensating the track search speed error value output from the calculator 53, and the track to the target track is applied. Since the track search speed appropriate to the search can be maintained, accurate track search operation can be performed.

However, an eccentric component may exist in an optical disk seated and inserted into a tray of the optical disk apparatus, or an eccentric component may exist due to an error in manufacturing the optical disk, or an eccentric component may exist due to an error in the clamping operation of the optical disk apparatus. As shown in FIG. 3, since the light spot emitted from the laser diode included in the optical pickup of the optical disk apparatus has an abnormal trajectory that irregularly traverses the track of the optical disk by the eccentric component, the track search operation is performed. When the track search is completed, the track search completion operation is completed in a section in which the number of track crossings is generated, that is, a section in which the frequency of the track crossing signal TZC is high. A large error occurs, resulting in the need to restart the servo operation. It was dots.

Accordingly, the present invention was created to solve the above problems, and when the track search operation is performed, the track search operation is completed in the section where the frequency of the track crossing signal TZC generated by the eccentric component of the optical disk is the lowest. Accordingly, an object of the present invention is to provide an apparatus and method for controlling a track search in an optical disk apparatus which can prevent a track search error caused by an eccentricity of the optical disk.

1 shows a configuration of a general optical disk device,

2 illustrates a detailed configuration of a servo unit of a general optical disk device.

3 shows an abnormal trajectory of an optical spot caused by an eccentric component of an optical disc,

4 shows a detailed configuration of the servo unit of the optical disk apparatus according to the present invention,

5A and 5B illustrate an operation flowchart of a track search control method in an optical disk device according to the present invention.

6 is a waveform diagram of a signal used for calculating a track search time required to a minimum eccentric position according to the present invention.

※ Explanation of code for main part of drawing

1: Optical disc 2: Optical pickup (P / U)

3: Filtering part (R / F) 4: Digital signal processing part

5: Servo part 6: Micom

7: Motor Driver 8,63: Memory

9: sled motor 10: spindle motor

51: track / cycle counting unit 52: speed calculating unit

53: calculator 54: track search controller

55: D / A converter 56: reference speed generation unit

57: low pass filter 58: high and low level detector

59: minimum eccentric position detector 60: pulse signal generator

61: timing controller 62: speed detector

In accordance with another aspect of the present invention, there is provided a track search control apparatus for an optical disk apparatus, comprising: calculating means for calculating a track search time required to a minimum eccentric position of an optical disk; When the track search operation time corresponding to the track search command is performed by comparing the calculated track search time to the minimum eccentric position and the estimated track search time to the target track transmitted in the received track search command, the track search operation corresponding to the track search command is performed. Control means for controlling the; And storage means for storing the track search estimated time required for each target track in a table form.

In addition, the track search control method in the optical disk apparatus according to the present invention comprises: a step of detecting a minimum eccentric position of the optical disk when the track search request; And variably controlling the time point at which the track search operation is performed to complete the requested track search operation at the detected minimum eccentric position.

Hereinafter, a preferred embodiment of a track search control apparatus and method in an optical disk apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

First, FIG. 4 shows the configuration of a servo unit of the optical disk apparatus according to the present invention, in particular, a servo unit for controlling a track search operation. As described above with reference to FIG. 2, a high frequency detected and output from the optical pickup 2 is shown. A ripple component square wave signal S1, a track crossing signal TZC, S2, and a signal S3 having the square wave signal S1 latched at the edge of the track crossing signal S2 as input signals, A track / cycle counting unit 51 for counting the track traversal number and its period; A reference speed generator 56 for generating and outputting a reference track search speed corresponding to the number of track traverses counted by the track / cycle counting unit 51; A speed calculator (52) for calculating a current track search speed based on the period of the track crossing signal calculated by the track / count unit (51); A calculator (53) for calculating the generated reference track search speed and the current track search speed calculated and outputting the difference value as a track search speed error (Error); A track search controller (54) which generates and outputs a kick pulse and a brake pulse to compensate for the track search speed error; A D / A converter 55 for converting the kick pulse or the brake pulse output from the track search controller into a track search driving signal TDO; A low pass filter 57 for low-passing the drive signal and outputting the drive signal as a low-frequency drive signal; A highest / low level detector 58 for detecting a highest level and a lowest level of the driving signal of the low frequency component; A pulse signal generation unit 60 for generating and outputting a pulse signal PG for detecting one rotation period of the optical disc by using the frequency signal FG output in correspondence with the rotational speed of the spindle motor for rotating the optical disc; A minimum eccentric position detection unit (59) for detecting a position where the eccentricity of the optical disc is minimized based on the pulse signal (PG), the frequency signal (FG), and the highest / low level detection signal; A rotational speed detection unit (62) for detecting a rotational speed of the optical disc based on the frequency signal (FG); A memory 63 for storing the estimated time required to the target track in the form of a table when performing the track search; On the basis of the rotational speed, the minimum eccentric position, and the estimated time required, the timing controller 61 delays the track search command requested from the microcomputer 6 for a predetermined time and outputs it to the reference speed generator 56. It is configured to include.

In the timing controller 61 of the servo unit configured as described above, when the track search operation is requested, the track search operation is completed in a section in which the frequency of the track crossing signal TZC generated by the eccentric component of the optical disk is the lowest. For this purpose, the track search command requested from the microcomputer 6 is output by delaying a predetermined time, and accordingly, the reference speed generator 56 outputs the generated reference track search speed by delaying the track search operation. Since the starting point of performance can be varied, the track search completion operation can be completed in the section where the frequency of the track crossing signal TZC is lowest, that is, in the center or the outermost portion of the optical disk where the optical disk has the smallest eccentricity. It will be controlled so that, the operation will be described in detail as follows.

First, FIG. 5 illustrates an operation flowchart of a track search control method in an optical disk apparatus according to the present invention. When the optical disk is seated and inserted, the spindle motor 10 as described above with reference to FIG. 1 is driven to rotate. The optical disk is rotated at a constant speed (S10), and the minimum eccentric position detection unit 59 counts the frequency signal FG generated by the rotational drive of the spindle motor 10, and the pulse. As shown in FIG. 6, the signal generator 60 generates and outputs a pulse signal PG corresponding to one rotation period of the optical disk using the frequency signal FG (S11).

Accordingly, the minimum eccentric position detection unit 59 counts the received frequency signal FG on the basis of the pulse signal PG (S12), and also from the highest / low level detection unit 58. The minimum level position and the highest level position of the detected track search driving signal TDO are respectively received, and the frequency signal count value up to the lowest level position, that is, counted to the lowest level position, is referred to the pulse signal. The value FG_cnt_bottom of the frequency signal and the value FG_cnt_peak of the frequency signal counted up to the highest level position are stored based on the pulse signal (S13).

Subsequently, a playback operation is performed according to a user key input (S14). During the playback operation, when a track search operation is requested, that is, according to the user key input, as described above with reference to FIG. 1, When a track search command is transferred from the microcomputer 6 to the timing controller 61, the track search command is held in the timing controller 61 while the track search command is held. The number of search tracks up to and including the target track included in the transmission is checked (S16).

On the other hand, the speed detector 62 detects the current optical disk rotation speed by using the frequency signal FG output from the spindle motor 10, and then outputs it to the timing controller 61. In the timing controller 61, the track search estimated time t-target corresponding to the current rotational speed of the optical disc and the number of search tracks to the target track is estimated by the track search estimated in the memory 63. The time table is searched and confirmed (S17).

On the other hand, the minimum eccentric position detection unit 59 counts the received frequency signal FG on the basis of the pulse signal PG output from the pulse signal generation unit 60 (S18). Using the current frequency signal count value FG_cnt_current, the track search time required to the minimum eccentric position (t_peak, t_bottom) is calculated (S19).

That is, when the optical disk is inserted and placed, the current signal FG_cnt_bottom counted to the lowest level position detected and stored by the operations S10 to S13 and the frequency signal FG_cnt_peak counted to the highest level position are present. Subtracting the frequency signal count value (FG_cnt_current) of each, the track search time required to the minimum eccentric position converted into time (t_peak = FG_cnt_peak-FG_cnt_current, t_bottom = FG_cnt_bottom-FG_cnt_current) is calculated (S19). The search time t_peak and t_bottom are transmitted to the timing controller 61.

Accordingly, in the timing controller 61, the track search time required (t_peak, t_bottom) from the minimum eccentric position detection unit 59 to the minimum eccentric position provided, and the target track searched and confirmed from the memory 63. It is determined whether or not the estimated time t-target is equal to, and when the determination result is matched (S19), the track search command held up to now is outputted to the reference speed generator 56 ( S21), the track search operation described above with reference to FIG. 2 is performed (S22).

In this way, the timing controller 61 holds the track search command received from the microcomputer 6 until the moment when the track search time required to the minimum eccentric position matches the estimated track search time required to the target track. By delayed output, the track search operation can be completed in the section where the frequency of the track crossing signal (TZC) generated by the eccentric component of the optical disk is the lowest, that is, the center portion or the outermost portion of the optical disk where the eccentricity of the optical disk is minimal To control.

The track search control apparatus and method in the optical disk apparatus according to the present invention as described above, when performing the track search operation, so that the track search operation can be completed in the center portion or the outermost portion of the optical disk to minimize the eccentricity of the optical disk By doing so, it is possible to prevent a track search error caused by an eccentric component of the optical disk due to an error in manufacturing the optical disk or an error in the clapping operation, and thus it is a very useful invention to perform and maintain a stable servo operation.

Claims (8)

Detecting a minimum eccentric position of the optical disc when the track search request is made; And And at the detected minimum eccentric position, variably controlling the timing of performing the track search operation to complete the requested track search operation. The method of claim 1, The minimum eccentric position is a track search control method of an optical disk apparatus, characterized in that the center portion or the outermost portion of the optical disk corresponding to a section in which the frequency of the track crossing signal (TZC) generated by the eccentric component of the optical disk is the lowest. . The method of claim 1, In the second step, the start time of the requested track search operation is controlled to be delayed by a predetermined time. A first step of identifying the optical pickup position on the optical disc when the track search request is made; Calculating a track search time corresponding to a movement distance from the identified optical pickup position to the requested target track position; And And variably controlling the movement speed of the optical pickup such that the track search operation is completed when the target track is located at the longest distance or the shortest distance from the center by the eccentricity based on the calculated required time. A track search control method in an optical disk device, characterized in that the configuration. The method of claim 4, wherein The first step is a track search control method for an optical disc apparatus, characterized in that the optical pickup position on the optical disc is grasped while the requested track search command is held. The method of claim 4, wherein The track search time required is calculated based on the number of track traverses to the target track. Calculating means for calculating a track search time required to the minimum eccentric position of the optical disc; When the track search operation time corresponding to the track search command is performed by comparing the calculated track search time to the minimum eccentric position and the estimated track search time to the target track transmitted in the received track search command, the track search operation corresponding to the track search command is performed. Control means for controlling the; And And a storage means for storing the estimated track search time for each target track in a table form. The method of claim 7, wherein And the control means delays the output timing of the received track search command so that the track search operation corresponding to the track search command is completed at the minimum eccentric position of the optical disc. Track Search Control.