KR20000014420A - Track search method of optical disk - Google Patents

Abstract

PURPOSE: A track search method of optical disk is provided to correct a slip error according to a load and characteristic of a slide motor and correctly search a track of an optical disk. CONSTITUTION: The method comprises the steps of: detecting a track error with an object track during track search operation, determining whether the track error is included within a predetermined allowable error range, and updating a predetermined correcting value according to a result of the determining operation. The number of the correcting track is updated when a slip error is generated according to a state of a spindle motor or a slide motor.

Description

Track Search Method for Optical Disc

The present invention relates to a track search method for an optical disc that compensates for slip errors. More particularly, the present invention relates to a track error due to slip during a track search operation that traverses a track of the optical disc in a vertical direction. Is a track search method for correcting a slip error according to a load and a characteristic of a spindle motor or a slide motor by updating a track search correction value so as to fall within a preset tolerance range. .

A typical optical disc player, as shown in FIG. 1, has a spindle motor 3 for rotating the optical disc 1 at a constant speed, and an optical pickup for reading out signals recorded on the optical disc. (2), a slide motor (4) for moving the optical pickup in the radial direction of the optical disc, a driver (8) for driving the spindle motor and the slide motor, and the read out A filter shaping part 5 for filtering the recording signal of the optical disk and outputting the RF signal as a radio frequency (RF) signal, and a synchronizing separator 6 for separating a sync signal from the filtered RF signal, and the separation; A digital signal processor (DSP) 9 which processes the RF signal into a digital signal according to the synchronized signal, and an MPEG which decodes the signal processed digital signal and outputs the original video or audio signal. MPEG) decoder 10 and the optical pickup and drive A servo unit 7 for controlling the servo operation of the fiber, a microcomputer 11 for detecting the track position information among the recording information of the optical disc included in the digital signal, and controlling the servo unit, and necessary for the control operation. It is comprised including the memory 12 which stores data.

Referring to FIG. 1, a conventional track search operation applied to a general optical disc player will be described.

First, when a user's track search key is input to the microcomputer 11, the track search mode is switched to recognize the track position to be searched, and the current track position that the optical pickup is reading is detected. The number of tracks corresponding to the difference value is calculated. That is, the number of tracks for moving to the track to be searched is calculated.

Thereafter, the calculated number of tracks and the number of correction tracks previously stored in the memory 12 are summed, and the servo unit 7 controls the driver 8 so that the optical pickup is tracked by the number of tracks obtained as a result. The slide motor is driven. On the other hand, the number of correction tracks is usually set by cumulative calculation of the track error corresponding to the experimental data obtained in the manufacturing process in consideration of the characteristics of the slide motor or spindle motor, the track search error due to the load and characteristics of the motor That is, it is used to prevent the track search error due to slip in advance.

However, in the conventional optical disc track search operation, the correction track number is set according to the experimental data on the manufacturing process performed under the limited conditions, thereby preventing all the slip phenomenon caused by various conditions, namely, changes in the load and characteristics of the motor, that occur during actual product use. In addition, since the number of correction tracks, which are set once, is fixed so that the user cannot arbitrarily correct, there is a problem that track search errors due to slip phenomenon continue to occur.

Accordingly, the present invention was created to solve the above problems, and detects a track error detected at the track search section by a predetermined number of times per track search section to determine whether a slip is detected and for each track search section. The purpose is to achieve accurate track search by updating and storing the error correction track number corresponding to the track error as the track search correction value or by varying and storing the magnitude of the slide driving voltage.

1 is a configuration diagram of a general optical disc player,

2 is a schematic diagram illustrating a track search method of an optical disc according to the present invention;

3 is a flowchart illustrating a track search method for an optical disc according to an embodiment of the present invention.

4 is a detailed flowchart of a track search method of an optical disc according to an embodiment of the present invention;

4 is a detailed flowchart of a track search method of an optical disc according to another embodiment of the present invention.

※ Explanation of code for main part of drawing

7: Servo 11: Micom

12: Memory 13: Position Detector

14: Logic Circuit (Logic)

The track search method for an optical disc according to the present invention for achieving the above object comprises the steps of detecting a track error with a target track during a track search operation, and whether the detected track error is within a preset tolerance range. And determining two steps, and updating the preset correction value according to the determination result.

According to the track search method of an optical disc according to the present invention, when a user's track search key is input, the track search method to calculate the difference between the track position to be searched and the current track position is calculated. The optical pickup is moved to the target moving track number, that is, the target track position by summing the number of correction tracks for each star. After that, if the error track number, which is the difference between the current track position and the target track position, is out of a certain number of times, the slippage is determined to be a slip, and the track search section corresponding to the error track number is determined. By updating and using the corrected track number, or by varying and storing the magnitude of the slide drive voltage, the track search error correction by the learning operation is performed.

Hereinafter, a preferred embodiment of a track search method for an optical disc according to the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a schematic configuration diagram for explaining a track search method of an optical disc according to an embodiment of the present invention. FIG. 2 shows track position information of digital data which is an output signal of a digital signal processor (DSP) 9 as described above. A track position detector 13 for detecting corresponding position data, and the number of correction tracks or slide driving voltages, which are correction values for each track search section, for correcting a slip phenomenon occurring during a track movement are stored. Based on the memory 12 and the position data and the number of correction tracks, the number of target movement tracks to the search track position to be searched, that is, the number of target tracks is calculated, and the correction track number is updated or slide driven. It is composed of a logic circuit (Logic) (14) for variable control of the magnitude of the voltage.

In the description of the operation according to the above configuration, first, when a search track selected by a user, that is, a specific track position is input to the logic circuit unit 14, the logic circuit unit recognizes the position of the specific track and detects the position detection unit. And receiving the current track position detected by the operation of detecting the current track position from the track position information data included in the digital data, and comparing the difference between the specific track position selected by the user and the current track position detected by the position detector. The number of chart tracks corresponding to the difference is calculated, and the number of correction tracks of the corresponding track search section is read out from the number of correction tracks for each track search section stored in the memory 12 and summed with the number of difference tracks for optical pickup. (2) calculate the number of target tracks to be moved. The jump track control signal (JTC: Jump Track Control) is applied to the servo unit 7 so that the track movement is performed as much as the target track number, so that the track movement is performed as much as the target track number calculated in this way.

When the track movement is completed by the above operation, a series of operations for detecting the number of error tracks are repeated a predetermined number of times by recalculating the difference between the current track position detected by the track position detecting unit and the target track position again. If the detected error track number is continuously out of the allowable error track number of a certain range over a predetermined number of times, it is determined as a slip error and a learn operation for updating and storing the corrected track number is performed.

On the other hand, in another embodiment, if the error track number detected through the above-described series of operations continuously out of the allowable error track number of a certain range as described above more than a predetermined number of times, it is also determined that the slip error to determine the slip error The learn operation of applying a slide drive voltage control signal (DVC) that varies the magnitude of the slide drive voltage for correction to the servo means 7 and updating and storing the variable slide drive voltage value in the memory. Will be performed.

Hereinafter, a detailed description of the track search method of the optical disk according to the present invention will be described in detail with reference to FIGS.

3 is an operation flowchart of the track search method of the optical disk according to the present invention, when the user's key input, that is, a key corresponding to the track search key is input, the microcomputer 11 recognizes this and selects the operation mode as the track search mode. By switching (S100), the search track which is the position of the track corresponding to the input track search key and the position of the current track detected by the position detector which is the track position detecting means 13 are compared. The track position difference, that is, the number of chart racks, is calculated (S101).

Thereafter, the calculated number of chart tracks compares whether the predetermined number of tracks (eg, 500) is exceeded (S102), and the predetermined number of tracks is preferably set to about 500 tracks. As a result of comparing the number of tracks below 500 tracks as a result of the comparison with a predetermined reference track number, the number of chart tracks is changed to the fine search mode (S109), so that the optical pickup maintains its current position and the objective lens in the optical pickup (microscope) The tracking servo operation that moves horizontally only, i.e., the short track jump operation, is performed.

On the other hand, when the number of chart tracks exceeds 500 tracks, a long track jump operation in which the optical pickup 2 is moved by the slide motor 4 as a whole is switched to the rough search mode. In this case, the track error correction value, that is, considering the unsafe factors due to the characteristics of the slide motor or the spindle motor, that is, the number of corrected tracks is read from the memory and summed with the number of the chart tracks (S104) to move to move during the long track jump. You get the number of tracks. This is called a target track, and the direction determination of the target track is determined in the circumferential direction or the inner circumferential direction of the optical disc, respectively, depending on whether the calculated number of chart tracks is positive or negative.

When the direction of the target track and the number of tracks are determined as described above, a track jump (S105) for traversing the track which is the recording surface of the optical disc by driving the slide motor is made. After the track movement is completed, the current track is again present. The position is detected and the deviation, that is, the number of error tracks, is calculated (S106) by comparing with the target track intended to be moved. It is determined whether the long track jump operation error occurs according to whether the calculated error track number exists within the tolerance range (S107).

As a result of the determination, when the number of error tracks is smaller than the number of tolerance tracks, it is determined to perform normal operation and is switched to the fine search mode for precise tracking (S109) to perform a series of operations. If larger, a learn operation S108 is performed to determine the track search error and update the preset track search error correction value.

The learning operation will be described in detail with reference to FIG. 4.

First, FIG. 4 is a detailed flowchart of a track search method of an optical disc according to an embodiment of the present invention. When the track search error is determined, the error count m is increased by +1 and the error track is simultaneously increased. The number is accumulated and stored (S201). When the cumulative number (m) of the error count exceeds a predetermined reference number (N), it is determined that the correction rack number setting, which is a track search error correction value preset in the memory, is incorrect (S202), and the cumulatively stored error track number is an average value. By updating and storing one new correction track number in a memory, when the target track (number) for long track jumping is calculated later, the newly updated correction track number is summed to make a more accurate track search operation. On the other hand, in a more specific embodiment, the error count (count) is a cumulative count for each jump track section, and the count number due to the error discrimination, if the normal operation is performed, that is, the error track is a tolerance track If not exceeded, the previously accumulated error count is reset to zero.

Hereinafter, the embodiment of the present invention as described above will be described with a more specific example.

First, assume that the search track position selected by the user is 1500 tracks, and the detected current track position is 500 tracks. The difference between the search track and the current track is calculated as 1000. In particular, it has a positive value, and the track movement direction is determined as the outer circumferential direction of the optical disc. In addition, since the number of chart tracks 1000 exceeds the reference track number 500, it is switched to the rough search mode, and the tracks are moved to the outer circumferential direction by adding the number of correction tracks preset to the chart tracks 1000 (eg, 100 tracks). The target track to be calculated is 1100. Afterwards, the slide motor is driven to move the optical pickup by the circumferential direction and 1100 tracks. At this time, the current track position is detected and the detected current track position is compared with the target track position. As a result, if the error track is 50 and the set reference tolerance track is 30, then the learning operation is performed.

In the learning operation, first, a track search error count corresponding to a search track section, that is, a 1000 to 2000 track section corresponding to 1500 tracks, is +1 accumulated, and the error track number 50 is accumulated and stored. Assuming that the accumulated error count number is 16 and the set predetermined number of times is 15, it is determined that the value of the set correction track number is set incorrectly, and the sum of the accumulated and stored error track numbers is divided by the error count number 16 to calculate the average value. If the calculated average value is 150, it is updated and stored in the memory. Therefore, after the target track calculation, the number of correction tracks updated from 100 to 150 is added up.

In addition, the learning operation according to another embodiment will be briefly described with reference to FIG. 5. FIG. 5 is a detailed flowchart of a track search method for an optical disc according to another embodiment of the present invention. When the track search error count (m) obtained through the series of operations (S100 to S107 and S300 to 302) described above continuously exceeds a predetermined number (N), the slide drive voltage value preset in the memory It is determined that the magnitude is incorrectly set, and an average value of the accumulated error track numbers is calculated. That is, the magnitude of the slide driving voltage preset in the memory is variably stored at a voltage size corresponding to the average error track number (S303). . Therefore, the slide motor which is driven during the track traversal movement is then driven in correspondence with the variable slide driving voltage.

The accurate track search is achieved by updating and storing the number of correction tracks preset by the above operation or by varying and storing the magnitude of the slide driving voltage.

The track search method of the optical disk according to the present invention is configured to update and store the number of correction tracks, which are track search correction values, when a slip error occurs according to the load and characteristics of a spindle motor or a slide motor. It is a useful invention which can suppress the track search error caused by the long time use of the optical disc player or the error in the manufacturing process by using it or by varying and storing the size of the slide drive voltage.

Claims (8)

Detecting a track error with a target track during a track search operation; Determining whether the detected track error is within a preset tolerance range; And And updating the preset correction value according to the determination result. According to claim 1, And based on the correction value updated in step 3, further comprising four steps of performing a requested track search operation. According to claim 1, The step 3 is a track search method for an optical disc, characterized in that the selection is performed by selectively updating different preset correction values for each track search section. Calculating the number of chart tracks between the requested target track position and the current track position detected after the movement; Step 2, transversing the track to a target track position where the calculated number of chart tracks and the number of preset correction tracks are added; Detecting an error track number that is a chart track number between the transversely moved current track position and a target track position; And And a four step of updating the preset number of correction tracks according to the detection result. The method of claim 4, wherein And the detecting operation of the third step is performed by comparing whether the error track number is within a predetermined range of tolerance track numbers. The method of claim 4, wherein Wherein the updating operation of step 4 accumulates at least two error tracks detected in step 3 and updates and stores the number of correction tracks. Calculating the number of chart tracks between the requested target track position and the current track position detected after the movement; Transversing the track to a target track position that adds the calculated number of chart tracks and the number of adaptively updated correction tracks during a search operation; Detecting an error track number that is a chart track number between the transversely moved current track position and a target track position; And And a four step of varying the magnitude of the slide driving voltage according to the detected number of error tracks. The method of claim 7, wherein And the variable operation of step 4 is variable to a magnitude of a slide driving voltage corresponding to an average value of the cumulative calculation of the number of error tracks of at least two times detected in step 3.