KR100186388B1 - Actuator protection device and method of optical disk reproducing system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing abnormal operation of a focus actuator and a tracking actuator in an optical pickup device of a CD player (CD-P) or a DVD player (DVD-P). In a conventional optical disc reproducing system, a focus actuator and a Even if the tracking actuator is in a situation in which it cannot be operated normally due to poor contact, external shock, or disconnection, the tracking actuator is not recognized and is driven as it is, resulting in a problem of expensive pickup device being damaged.

Therefore, in order to solve this problem, the present invention includes: actuator drive voltage detection means for detecting a drive voltage supplied to the focus actuator and the tracking actuator in the initial driving state; The focus actuator driving voltage and the tracking actuator driving voltage detected by the actuator driving voltage detecting means are compared with a preset reference voltage, respectively, and when the one or more deviations from the allowable value, the player is suspended and the control is notified to the outside. It comprises a means.

Description

Actuator protection device and method for optical disc playback system

1 is a block diagram showing an embodiment of an actuator protection device of an optical disc reproducing system according to the present invention.

2 is a signal flowchart of an actuator protection method of an optical disc reproducing system of the present invention.

* Explanation of symbols for main parts of the drawings

1: disc motor 2: disc

3: optical pickup device 4: focus error generating unit

5: Focus actuator driving voltage detector 6: Tracking error generator

7: Tracking actuator drive voltage detection unit 8: A / D conversion unit

9: Digital servo integrated device 10: Error display unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing abnormal operation of a focus actuator and a tracking actuator in an optical pickup device of a CD player (CD-P) or a DVD player (PV-P). Particularly, the present invention relates to a focus actuator or tracking device in an initial driving stop state. The present invention relates to an actuator protection apparatus and method for an optical disc reproducing system, which is configured to suspend a player's driving when there is a possibility of abnormal operation by judging whether the actuator can be driven normally and to notify the outside thereof.

Typically, servo systems in optical disc playback systems, such as CD-P (Compact Disc-Player) or DVD-P (Digital Video-Player), are laser output servos that keep the oscillation output of the laser diode constant. CLV servo that drives the disc motor at a constant linear velocity, a focus servo that focuses on the disk reflecting surface, a tracking servo that tracks a constant track, and an optical transmission servo that moves the optical pickup body. The following describes the operation of the tracking servo system.

First, the operation of the focus servo system is described. In the optical disc reproducing system, the objective lens mounted on the optical pickup device has a small depth of focus (CD: ± 1 μm). Getting it right is not difficult at all. Even if the focus is corrected at any moment, the distance between the disc and the optical pickup will continue to change due to the disc deflection and eccentricity.

Thus, the coil is wound around the objective lens block placed in the magnetic field and moved to the optical axis direction with a servo signal like the voice coil of the speaker so that the position of the lens is adjusted so that the reflective surface of the disk is brought into the depth of focus.

To this end, first, the disc is inserted into an optical disc reproducing system, and then the objective lens is moved up and down with a signal of a 1-2 s oscillation circuit called a focus servo circuit. This brings the disk's reflecting surface closer to the depth of focus of the lens, so the first noise-focusing error starts to be output from the focus-error detection circuit. Immediately after detecting the error signal, the focus servo system is operated to fall within the depth of focus of the objective lens.

In addition, explaining the operation of the tracking servo system, the tracks of the optical disc are arranged at very fine intervals (CD: 1.6 μm), and the number of tracks is about 20,000 tracks on the disc of 1 hour of running time. have. Therefore, if you look at the disk microscopically, it is a realistic problem that there is no choice but to rotate with more or less eccentricity.

In the optical pickup apparatus, a track (pit group) having a predetermined width (CD: 0.5 mu m) is rotated like a waveform of an irregular wave. The function of tracking servo is to inject the laser while accurately searching the track, and the basic operation is performed by the tracking detection circuit, which generates an electric signal corresponding to the beam trace state, and based on the signal, the objective lens and The predetermined track is tracked by moving the optical pickup main body in the radial direction to correct the position of the beam.

On the other hand, as a driving device for performing the focus servo and tracking servo as described above, the focus actuator and the tracking actuator installed in the direction in which the focus coil and the tracking coil are orthogonal to the objective lens block are used. It is no exaggeration to say that system performance depends.

Nevertheless, in the conventional optical disc reproducing system, even if the focos and tracking actuators cannot operate normally due to contact failure, external shock, or disconnection, they are not recognized and are driven as they are. Problems such as damage to the pickup device have occurred.

Accordingly, a first object of the present invention is to provide an apparatus for protecting a pickup actuator by detecting an abnormality of a servo signal, and detecting a abnormality of pickup by detecting a voltage of an optical pickup actuator. A second object of the present invention is to provide an apparatus for detecting the presence or absence of an abnormal signal for a servo and indicating an error in an abnormality. A third object of the present invention is to provide an apparatus that combines A / D conversion of an servo input signal and A / D conversion for an optical pickup actuator protection device.

The actuator protection device of the optical disc reproducing system of the present invention for achieving the above object comprises: actuator drive voltage detection means for detecting a drive voltage supplied to a focus actuator and a tracking actuator in an initial state of driving; In the normal driving state, the focus error and tracking error are corrected based on the focus error signal and the tracking error signal, and in the initial driving state, the focus actuator drive voltage and the tracking actuator drive voltage detected by the actuator drive voltage detection means are preset. It includes a control means for holding the player's driving when any one or more of the voltage is compared with each other, and notifying the fact to the outside.

FIG. 1 is a block diagram showing an embodiment of an actuator protection device of an optical disc reproducing system of the present invention for achieving the above object. As shown in FIG. 1, a CLV servo system is controlled to rotate at a predetermined speed (CLV). An optical pickup apparatus (3) for scanning a laser at a designated position of the disc motor (1) and the disc (2) rotated by the disc motor (1), and converting the reflected light into a plurality of electrical signals and outputting the same. ) And a focus error generator 4 and a tracking error signal et that generate a focus error signal ef by subtracting and subtracting an electrical signal af converted into an electrical signal by the optical pickup device 3. A tracking error generator 6 for generating a tracking error, a focus actuator drive voltage detector 5 and a tracking actuator drive voltage detector 7 for detecting drive voltages supplied to the focus actuator and the tracking actuator, respectively, and a switching agent. Under the control of the signal SC, the output signals of the focus actuator driving voltage detector 5 and the tracking actuator driving voltage detector 7 are selected in the driving initial state, and in the driving state, the focus error generator 4 and the tracking error are selected. Switches SW1 and SW2 for selecting and outputting the output signal of the generator 6 and A / D converters 8 for converting the analog signals output from the switches SW1 and SW2 into digital signals. And the focus error and tracking error are corrected based on the focus error signal and the tracking error signal supplied through the A / D converter 8 in the normal driving state, and the A / D converter ( 8) the focus actuator driving voltage and the tracking actuator driving voltage supplied through the reference voltage are compared with the preset reference voltage, respectively, to suspend the player's driving when one or more deviations are allowed, and the fact is displayed on the error display unit 10. The digital servo integrated device 9 to be displayed is described in detail with reference to FIG. 2 attached to the operation and effect of the present invention configured as described above.

If it is normal in the initial state when the power is started to be supplied, a voltage of almost zero level will be detected since no driving voltage is supplied to the focus actuator and the tracking actuator.

To check this, in the initial state, the digital servo direct element 9 outputs the switching control signal SC to the switches SW1 and SW2 so that the respective switches SW1 and SW2 are fixed terminals b1, It is shorted to (b2).

Accordingly, the analog voltage detected through the focus actuator drive voltage detector 5 and the tracking actuator drive voltage detector 7 is supplied to the A / D converter 8 through the respective switches SW1 and SW2. It is converted into a digital signal and then supplied to the digital servo integrated device 9.

In this case, the digital servo integrated device 9 supplies the focus actuator driving voltage and the tracking actuator driving voltage input through the path to OV corresponding to a predetermined reference voltage, that is, a ground potential, and an allowable error α. When the focus actuator driving voltage or the tracking actuator driving voltage is higher than the reference voltage, it is regarded as an abnormal state in which the system cannot be normally operated, and an error state is displayed on the error display unit 10 and the cause of error is resolved. Suspend operation of the system until

However, if the focus actuator driving voltage or the tracking actuator driving voltage is lower than the reference voltage as a result of the determination, the switch SW1 and SW2 are switched to the fixed terminals a1 and a2. Let's do it. In this state, the disc motor 1 and the optical pickup device 3 are driven.

At this time, the light reflected from the disk 2 is converted into a plurality of electrical signals af through the optical pickup device 3 and then transmitted to the focus error generating unit 4 and the tracking error generating unit 6. do. Accordingly, the focus error generating unit 4 adds the electrical signal (a-b + c-d), amplifies the result value to a specified level, generates a focus error signal ef, and the tracking error. The generation unit 6 obtains the difference signal af of the electrical signal, amplifies the resultant value to a specified level, and generates a tracking error signal et.

The analog focus error signal ef and tracking error signal et generated as described above are converted into digital signals through the switches SW1 and SW2, and the digital servo integrated device 9 is converted into the digital signals. The focus error signal and the tracking error signal are compensated for based on the focus error signal and the tracking error signal, thereby performing a normal playback function.

As described in detail above, the present invention detects whether the driving voltage is unexpectedly supplied to the focus coil and the tracking coil in the initial driving stop state, and based on this, the focus actuator or the tracking actuator is normally driven. It is possible to prevent the pickup device from being unstable and damaged by suspending the driving of the player when there is a possibility of abnormal operation by determining whether it is possible and notifying the fact to the outside.

Claims (4)

Actuator driving voltage detecting means for detecting a driving voltage supplied to the focus actuator and the tracking actuator in the initial driving state; The focus actuator driving voltage and the tracking actuator driving voltage detected by the actuator driving voltage detecting means are compared with a preset reference voltage, respectively, and when the one or more deviations from the allowable value, the player is suspended and the control is notified to the outside. Actuator protection device for an optical disc playback system comprising a means. 2. The actuator protection apparatus of an optical disc reproducing system according to claim 1, further comprising error display means for informing an error message to a user when the level of said actuator driving voltage is out of a predetermined value. The method of claim 1, wherein the focus actuator driving voltage and the tracking actuator driving voltage are configured to be converted into a digital signal through a D / A converter for converting the focus error voltage and the tracking error voltage into a digital signal and supplied to the control means. Actuator protection device for optical disc playback system. An actuator control method of an optical disc reproducing system, comprising: detecting an actuator driving voltage; Comparing the drive voltage to a reference value and switching the system to a normal mode if the reference value is within a reference value, and stopping the operation of the system and displaying an error if the reference value is out of the reference value. .