JP2557587Y2 - Optical disk player - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an optical disk player such as a CD player.

[0002]

2. Description of the Related Art In an optical disk player, during normal reproduction, a tracking actuator follows a track, a sled motor operates intermittently to move a pickup, and the tracking actuator operates only near the center thereof. ing. This will be described with reference to FIGS. In the generation of the tracking error signal by the three-beam method, the main beam spot 11, the sub-beam A spot 12, and the sub-beam B spot 13 are arranged at positions shifted from the track 50 as shown in FIG. Each spot is finally returned to the light receiving elements 20 to 25 shown in FIG. 7 by the optical system in the optical pickup, and is tracked via the OP amplifier 26 based on the difference between the outputs of the light receiving elements 24 and 25. It is configured to generate an error signal. That is, when the sub beam A spot 12 and the sub beam B spot 13 are evenly displaced from the track 50 as shown in FIG. 6, the outputs of the light receiving elements 24 and 25 become equal, and the tracking error signal becomes It becomes zero as shown by the dot. When the respective beams are displaced in the direction a with respect to the track 50 as shown in FIG. 6, the output of the light receiving element 24 decreases and the output of the light receiving element 25 increases. Ha-side. Conversely, in the case of FIG. 6, the tracking error signal is in the + direction as shown by the point in FIG. Thus the truck 50
Since an error signal having a polarity opposite to the direction of deviation from the error signal is obtained, the error signal is amplified by the OP amplifier 26 and controlled so that the main beam is always positioned at the center of the track 50.
That is, as shown in FIG. 5, the actuator (tracking coil 3 ') inside the pickup is controlled via the tracking drive unit 2'. FIG.
In the above, the tracking phase compensator 1 'is a filter circuit for optimizing the frequency response characteristics of the control system so that tracking control is performed stably, and is generally constituted by an OP amplifier and a CR. As the three beams follow the track 50 by the tracking control, the position of the objective lens 52 with respect to the main body of the pickup 51 also moves in the direction A from position A to position B as shown in FIG. At the same time, the tracking coil drive voltage changes from point A to point B in FIG. As shown in FIG. 11, only the DC component of about 1 Hz or less of the tracking coil driving voltage waveform is taken out by the thread LPF section 4 ', and the thread motor 6' is driven via the thread drive section 5 'to drive the pickup body. I try to make it. That is, in this thread control operation, as shown in FIG. 9, when the objective lens 52 moves in the A direction from A to B,
The sled motor drive voltage rises from a in FIG. 11 to b,
When the voltage becomes sufficient to drive the motor, the pickup main body moves in the direction A, and the objective lens 52 is positioned near the center of the main body of the pickup 51 as shown in FIG. At this time, the tracking coil driving waveform becomes as shown in FIG. 10 and the sled motor driving waveform also drops as shown in FIG. This operation is repeated in the thread control operation.

[0003]

In the above configuration, when the load on the sled operation mechanism is increased, the motor is not driven by the voltage at point B in FIG. The lens 52 further moves in the direction A and follows the track. As a result, both the tracking coil drive voltage and the sled motor drive voltage continue to rise, and when the sled motor drive voltage overcomes the load, the pickup 51 moves as shown by the point J in FIG. At this time, since the objective lens 52 moves suddenly over a larger distance than usual, there is a problem that the tracking servo is easily disengaged and sound skipping is likely to occur. The purpose of the present invention is to improve such problems.

[0004]

In order to achieve the above object, an optical disk player according to the present invention is provided.
Optical pickup that reproduces the information
Sled motor that moves the tape in the radial direction of the optical disk
And the reflected light of the optical disk received by the optical pickup
That generates a tracking error signal using
And a tracking error signal.
Therefore, a signal for driving the thread motor is generated.
A thread drive section to be driven and an output of the thread drive section.
Force is detected and the output value is higher than the specified value
While the gain of the thread drive section is increased
And gain switching means for switching between the two.

[0005]

A tracking error signal is generated due to a shift of an optical spot of an optical pickup for reproducing information recorded on an optical disk, and a signal for driving a thread motor for driving the pickup is generated by the tracking error signal. Generated in the department. By detecting the output of this thread drive unit, the
While the output value is equal to or greater than a predetermined value, it switches the gain of said sled drive unit to a larger gain, suppressing generation of thereby skipping.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a tracking error signal is input to a tracking drive section 2 via a tracking phase compensating section 1 to control a tracking coil 3 to move the objective lens 52 so that the objective lens 52 is always positioned at a correct position. The output of the tracking drive unit 2 shown in FIG. 2 is input to the sled LPF unit 4, where the drive of the sled motor 6 is controlled via the sled drive unit 5 from which only the DC component is extracted, and the sled control operation is performed. It is configured. The output of the thread drive unit 5 is detected by the voltage detection unit 7 and compared with a predetermined value VTH. When the output is equal to or higher than the predetermined value VTH, a gain switching signal is output to the thread drive unit 5. In the above configuration, as shown in FIG. 3, when the voltage of the thread drive unit 5 becomes equal to or higher than the predetermined value VTH at the point B, the voltage detection unit 7 outputs a gain switching signal to the thread drive unit 5, whereby the thread drive unit 5 is the output voltage of FIG.
As shown in the figure rises sharply. By the large voltage at the β point, the sled motor 6 overcomes a large load and moves the pickup. Therefore, as shown in FIG. 13, the objective lens 52 does not largely move, and it is possible to suppress the occurrence of sound skipping.

When the displacement of the objective lens 52 relative to the main body of the pickup 51 during normal operation is d, the sled motor drive waveform Vs has a substantially proportional relationship, and the drive torque of the motor is substantially proportional to Vs. The displacement of the objective lens 52 at which sound skipping is likely to occur when the thread load increases is about three times or more of d, and there is almost no problem if it is less than d. That is, if the driving load is increased to a level at which the feed operation of the pickup occurs when Vs is about three times or more than normal, sound skipping is likely to occur.
Assuming that VTH = 2Vs and the gain of the thread drive unit 5 at the time of gain switching is twice the normal value, when the driving load is about 2 to 4 times the normal, the conventional Vs becomes about twice or less the normal value by the gain switching. Perform the same playback operation. Further, until the driving load becomes about six times the normal value, the conventional Vs performs a reproduction operation equivalent to about three times or less the normal value, and the skipping is likely to occur more than that. Conventionally, skipping is likely to occur when the driving load is about three times or more than normal, whereas in the above-described configuration, occurrence of skipping is prevented even if the load is increased to about six times or more than normal. Becomes possible.

FIG. 4 shows an example of a specific circuit of the thread drive section 5 and the voltage detection section 7. The voltage detection unit 7 includes a transistor TR3 and resistors R2 and R3. When the gain switching signal is L, the gain GN is

(Equation 1) However, when the gain switching signal is H, the transistor T
Since R3 turns on, the gain GU at that time is

(Equation 2) Becomes here

(Equation 3) If,

(Equation 4) Therefore, the ratio of GN to GU can be selected by R2 and R3. what if

(Equation 5) given that,

(Equation 6) Becomes Note that the above circuit is an example, and the present invention is not limited to this. The circuit can be realized by another gain-switchable amplifier circuit.

As described above, in the above configuration, the output of the sled drive section 5 is configured to increase as shown in FIG. 3 by the voltage detection section 7 when the output reaches the predetermined value VTH. It is possible to suppress the occurrence of sound skipping.

[0010]

As described above, the optical disc player of the present invention detects the output of the thread drive unit and increases the gain of the thread drive unit while the output value is equal to or higher than the predetermined value. since the switching so that the even if the thread operating mechanism is abrasion in the sliding portion or the like is deteriorated becomes larger the load occurs, the operation performance of the sled mechanism unit without reduced, skipping the generation Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the operation of the embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of one embodiment of the present invention.

FIG. 4 is a circuit diagram showing an embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional configuration.

FIG. 6 is an explanatory diagram of a configuration for generating a tracking error signal.

FIG. 7 is an explanatory diagram of a configuration for generating a tracking error signal.

FIG. 8 is an explanatory diagram of a configuration for generating a tracking error signal.

FIG. 9 is an explanatory diagram of a thread control operation.

FIG. 10 is an explanatory diagram of a thread control operation.

FIG. 11 is an explanatory diagram of a thread control operation.

FIG. 12 is an explanatory diagram of the operation of the conventional configuration.

FIG. 13 is an explanatory diagram of the operation of the conventional configuration.

[Explanation of symbols]

1: tracking phase compensator, 2: tracking drive, 3: tracking coil, 4: thread LPF
Section, 5: thread drive section, 6: thread motor,
7: voltage detector, 11: main beam spot, 12: sub beam A spot, 13: sub beam B spot, 20: light receiving element, 21: light receiving element, 22: light receiving element, 23: light receiving element, 24: light receiving element , 25: light receiving element, 26: OP amplifier, 50: track, 51: pickup, 52: objective lens.

Claims (1)

(57) [Scope of request for utility model registration] 1. A tracking by using the optical pickup for reproducing information recorded on an optical disc, a thread motor for moving the optical pickup in a radial direction of the optical disk, the reflected light of the optical disk is received by the optical pickup error A tracking error signal generating means for generating a signal; a sled drive section for generating a signal for driving the sled motor in accordance with the tracking error signal; and detecting an output of the sled drive section to obtain an output value.
An optical disc player, comprising: gain switching means for switching the gain of the thread drive unit to a larger gain while the value is equal to or more than a predetermined value .