KR100294894B1 - Apparatus for generating lowest concentricity point and method for seeking optical disk - Google Patents

Abstract

An optical disc lowest eccentricity generator for generating the lowest track eccentricity on a mounted disc using the hall signal of the optical disc spindle motor and an optical disc searching method using the same have been disclosed. The present invention provides a spindle motor means for outputting a plurality of Hall signals at predetermined phase intervals by a plurality of Hall sensors mounted therein when rotating the optical disk; Multiplication means for inputting hall signals of a predetermined phase interval generated by the spindle motor means to generate hall pulse signals multiplied by a predetermined integer multiple; Comparison means for generating an index signal corresponding to the lowest eccentric point whenever the two values coincide by comparing the count value of the hall pulse generated by the multiplication means with a reference value which is a predetermined disk rotation period; And control means for generating a tracking control signal that attempts to re-enter a track whenever an index signal occurs in the comparison means.

Description

Apparatus for generating lowest concentricity point and method for seeking optical disk}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc lowest eccentricity generating device and an optical disc searching method using the same. In particular, an optical disc minimum eccentricity generating device generating a minimum track eccentric point on a mounted disc using a hall signal of an optical disc spindle motor and using the same An optical disc search method.

Generally, the optical disk drive includes an optical disk 130, a spindle motor 110 for rotating the optical disk 130, an optical pick 120, and a transport motor 140 for driving the optical disk drive. The optical pick 120 also includes a focusing actuator (not shown) used to focus the laser on the recording surface on the optical disc 130, and a tracking actuator (not shown), where the laser focus is used to follow the track on the disk. Included.

Since the tracking actuator has a limitation in the moving distance, in the case of the long distance movement, the optical spot is moved by using the optical pick-up feed motor 140 such as a DC motor or a step motor. At this time, when moving the distance as shown in the flow chart of Figure 2 (Coarse Seek) is performed. Referring to the flowchart of FIG. 2, when the coarse search is started, the tracking control is stopped (step 210) and the pick-up feed motor 140 is moved to the target point (step 220). When the motor 140 reaches the target point and the optical pickup is stopped (step 230), the tracking re-entry should be attempted to put the light spot on the track again.

At this time, if the disc's rotation speed was low (e.g. a low speed CD-ROM drive) and the pitch between tracks of the disc was large and the amount of eccentricity was short, tracking reentry was possible immediately. If the speed (speed at which the optical spot by the tracking actuator traverses the track) is so fast that tracking reentry is impossible, the disk is rotated and waits to find the point where the track eccentric frequency is low. That is, while rotating the disc, the minimum track eccentric speed is updated until the current track eccentric speed reaches the lowest point (steps 240, 250, 260). At this time, if the current track eccentric speed is similar to the minimum track eccentric speed, tracking control starts (step 270). As described above, before the track reentry, the point where the track eccentric speed is the lowest is found and used as the reference point of the track reentry point. However, to find this lowest eccentric position, measure the distance between the tracks by rotating the disc at least half a turn. For example, when calculating the time on an 8x CD-ROM drive, the track linear velocity = (1.3m / sec) * 8, and the time required for 1/2 rotation in the inner circumference of the disc (radius 30mm) = 72.5msec / 8. In addition, after finding the lowest eccentric point, it must wait until the next lowest eccentric point for the re-entry of tracking. . As described above, in the conventional method, the time required for coarse seek to move a long distance on the disk becomes inversely proportional to the rotational speed of the disk, which causes the overall performance of the optical disk drive. There was this.

The technical problem to be achieved by the present invention is the lowest eccentricity generating device of the optical disk drive for generating a signal indicating the lowest eccentric point on the disk using the Hall signal of the spindle motor and an optical disk searching method for re-entering the track using the same. To provide.

1 is a perspective view showing a general optical disk drive device.

FIG. 2 is a flowchart illustrating a coarse seek method performed in the optical disk drive apparatus of FIG. 1.

3 is a block diagram of an optical disc lowest eccentricity point generator according to the present invention.

4 (a) to 4 (g) are operation waveform diagrams of the respective block of the apparatus of FIG. 3.

5 is a flowchart illustrating a method of searching for an optical disc using the apparatus of FIG. 4.

In order to solve the above technical problem, the present invention is the lowest eccentric point generating apparatus of the optical disk drive,

Spindle motor means for outputting a plurality of Hall signals at predetermined phase intervals by a plurality of Hall sensors mounted therein when the optical disk rotates;

Multiplication means for generating hall pulse signals multiplied by a predetermined integer by inputting hall signals of a predetermined phase interval generated by the spindle motor means;

Comparison means for generating an index signal corresponding to the lowest eccentric point whenever the two values coincide by comparing the count value of the hall pulse generated by the multiplication means with a reference value which is a predetermined disk rotation period;

And a control means for generating a tracking control signal which attempts to re-enter a track whenever an index signal is generated in the comparing means.

In order to solve the above other technical problem, the present invention includes a spindle motor for generating a hall signal at a predetermined phase interval by rotating the optical disk, and a pick-up feeding motor for transferring the optical pick up, the method for searching for a long distance of the optical disk,

Stopping the tracking control to move the pick-feed motor to a target point when a long-range search is started;

Attempting to enter tracking when the pick-up motor reaches a target point in the process;

Recognizing the track eccentric speed as the lowest point every time the count value of the hall signal generated by the spindle motor and the reference value corresponding to the predetermined rotation of the disk coincide with each other. An optical disk search method.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram of the optical disc lowest eccentric point generating apparatus according to the present invention, the spindle motor 310, multiplier 320, up / down counter 330, comparison unit 340, level The state converter 350 and the controller 360 are configured.

4 (a) to 4 (g) are operation waveform diagrams of the respective block of the apparatus of FIG. 3.

First, the present invention uses a hall signal for detecting the rotational speed generated from the spindle motor 310 during the optical disk operation. The Hall signal is generated in the form of a pulse in accordance with the direction of the external magnetic field by a plurality of Hall sensors mounted at predetermined angular intervals inside the spindle motor 310. That is, the three spindle motors 310 are arranged in the direction of the external magnetic field at phase intervals of 120 ° from each other, as shown in FIGS. 4A to 4C, from three Hall sensors mounted at 120 ° phase difference therein. Accordingly, Hall signals (Hall A, Hall B, Hall C) are generated in parallel.

The multiplication unit 320 combines Hall signals Hall A, Hall B, and Hall C of the spindle motor 310 to generate a multiplied Hall pulse signal as shown in FIG. The down / down counter 330 counts down / down counts the multiplied hall pulses generated by the multiplying unit 320 as shown in FIG. 4E and outputs the count value. At this time, the down / down counter 330 counts pulses generated by the three-phase spindle motor 310 at 36 times per disc revolution and 18 times per half revolution. The comparator 340 compares the count value input from the up / down counter 330 with a reference value (for example, 0-17 corresponding to one-half rotation of the disc) and generates a coincidence signal when the two values match. . The reference value can be set differently according to the spindle motor specification. The level state converting unit 350 converts the level (high or low) state by the coincidence signal generated by the comparing unit 340, and the count value is 1 / s of the spindle motor as shown in FIG. An index signal is generated every '17' times that corresponds to two revolutions. The controller 360 determines the track entry by controlling the tracking actuator in order to re-enter the track whenever the index signal is changed from the level converter 350. In addition, the controller 360 generates a reset signal at the initial track entry point as shown in (f) of FIG. 4 at a necessary moment to clear the count value of the down / down counter 330. At the same time, the index signal is converted to the default value.

Therefore, in the initial stage of operation of the optical disc drive, if the track error is monitored in the focusing only mode to clear the down / down counter 330 at the lowest eccentric speed and there is no slippage between the disc and the spindle motor 310. The track eccentric speed is always lowest at the point where the index signal is changed. Attempting to reenter the track at the point where the index signal level state is changed always attempts to reenter the track at the lowest eccentric speed.

5 is a flowchart illustrating a method of searching for an optical disc using the apparatus of FIG. 4.

First, if coarse search is started in step 510, the tracking control is stopped. In operation 520, the pick transfer motor is operated to move to a desired target point. In step 530, when the pick-up motor reaches the target point and the optical pick-up feed stops, re-entry the tracking to put the light spot on the track again. At this time, it is checked whether the index signal changed in step 540. The level state of the index signal changes whenever the count value for the hall signal reaches a time corresponding to 1/2 rotation of the spindle motor. Accordingly, since the point in time at which the state of the index signal changes in step 550 is the point at which the track eccentric speed is the lowest, the tracking control starts.

The present invention is not limited to the above-described embodiment, and of course, modifications can be made by those skilled in the art within the spirit of the present invention. That is, it is applied to all kinds of optical disc drives, especially when the rotation speed is high.

As described above, according to the present invention, it is possible to save time waiting for finding the lowest eccentric point and waiting time for re-entry the track to the next lowest eccentric point as in the prior art. For example, in the case of an 8x CD-ROM drive, when searching in the innermost circumference (disc center), the time required to find the lowest eccentricity after the pick-up motor stops is the minimum 1/2 disk rotation time. Finding a point and waiting for the next lowest eccentric point to reenter the track also takes half the disk rotation time. However, the application of the present invention only takes a maximum of 1/2 disk rotation time.

Claims (4)

In the lowest eccentricity generating device of an optical disc drive, Spindle motor means for outputting a plurality of Hall signals at predetermined phase intervals by a plurality of Hall sensors mounted therein when the optical disk rotates; Multiplication means for generating hall pulse signals multiplied by a predetermined integer by inputting hall signals of a predetermined phase interval generated by the spindle motor means; Comparison means for generating an index signal corresponding to the lowest eccentric point whenever the two values coincide by comparing the count value of the hall pulse generated by the multiplication means with a reference value which is a predetermined disk rotation period; And control means for generating a tracking control signal which attempts to re-enter a track whenever an index signal is generated in the comparing means. The apparatus of claim 1, wherein the control means is a means for generating a reset signal at an initial track entry point to initialize a count value. 2. The apparatus of claim 1, wherein the comparing means is a means for generating a coincidence signal corresponding to the lowest eccentric point at every 1/2 turn of the spindle motor. In the method of searching for a long distance of the optical disk, including a spindle motor for rotating the optical disk to generate a hall signal at a predetermined phase interval, and a pick-up feeding motor for transferring the optical pick up, Stopping the tracking control to move the pick-feed motor to a target point when a long-range search is started; Attempting to enter tracking when the pick-up motor reaches a target point in the process; Recognizing the track eccentric speed as the lowest point every time the count value of the hall signal generated by the spindle motor and the reference value corresponding to the predetermined rotation of the disk coincide with each other. An optical disc searching method.