JPH07134835A - Optical disk reproduction device - Google Patents

Abstract

PURPOSE:To achieve the reproduction operation of an optical disk reproduction device by equipping a means for detecting that a tracking servo control does not converge and a means for increasing the sensitivity of a servo means when the non-convergence of tracking servo control is detected by the detection means. CONSTITUTION:Digital signal read by a pick-up 14 is amplified to a specific level by a preamplifier 15 and sent to a signal conversion circuit 16 and then is input to a tracking error detection part 17, a focusing error detection part 18, a mirror detection circuit 19, and a disk servo circuit 20. The detection part 17 detects that the focusing position of reading rays applied from the pick-up 14 deviates to the inside/outside from the track of an optical disk 11 according to the output signal of the pick-up 14 and then outputs it to a tracking servo circuit 21. This circuit 21 controls operation/non-operation according to the output signal from a microcomputer 22 and drives an actuator for tracking (not shown here) so that reading rays follow the track of the optical disk 11 in response to the signal from the tracking error detection part 17 in operation state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc reproducing apparatus for reproducing a compact disc or the like.

[0002]

2. Description of the Related Art An optical disk reproducing apparatus optically reads and reproduces a signal recorded on an optical disk. That is, the signal recording portion (hereinafter referred to as a track) arranged in a spiral shape of the optical disc is irradiated with a light beam, and the reflected light that changes according to the signal recorded on the track is received, so that the signal is recorded on the optical disc. Read and play the signal. However, in order to read the signal recorded on the optical disk, it is necessary to follow the track of the optical disk and irradiate the light beam accurately, and it is also necessary to focus the optical system.

For this reason, the optical disc reproducing apparatus has
Various servo devices are provided. This is to control various actuators by a feedback system from the state of the signal recorded on the optical disc which is read by a pickup which irradiates the track of the optical disc and receives the reflected light which changes according to the signal recorded on the track. The main ones are a tracking servo that controls the pickup to follow the track spirally arranged on the optical disc, a focus servo that focuses the optical system, and a disc rotation servo that controls the rotation speed of the optical disc. There is a pickup feed servo for feeding the pickup to a portion where a predetermined signal is recorded according to the operation of the operator.

By the way, in the optical disc reproducing apparatus, there is an operation called a track jump in order to jump over tracks to select a desired music. The pickup feed servo moves the pickup across the track group in the radial direction of the optical disc in order to quickly align the pickup with the position of the track on which the desired song is recorded according to the key operation by the operator. When the pickup is moved to, and the target track is approached, the objective lens built in the pickup is driven by the tracking servo device to match the desired track. That is, when performing this track jump, the microcomputer first issues a pickup movement command to the pickup feed servo device, and the pickup feed servo for controlling the pickup starts the pickup movement. Then, the microcomputer counts the track crossing signals, issues a pickup movement stop command when crossing the target number of tracks, and thereafter finely adjusts the pickup position by the tracking servo and controls so that a recording signal (subcode) is input.

[0005]

However, for example, in a vehicle-mounted optical disc reproducing apparatus, there is a subtle change due to a change in ambient temperature and a temperature rise of the pickup due to heat generation from the optical disc reproducing apparatus itself or a secular change. Tracking servo systems that require control may not work well. Especially when the track jump is instructed to the desired song by the operator's key operation, the servo is unlocked and the focus position of the pickup deviates more than the track, so that the tracking servo control does not converge, that is, the focus position of the pickup. Sometimes swayed around the track and could not follow the track well. An object of the present invention is to improve the above-mentioned drawbacks of the prior art and to operate a pickup in an optical disk reproducing apparatus under appropriate operating conditions.

[0006]

In order to achieve the above object, the present invention is an apparatus for reproducing an optical disk, which follows a signal recorded in a signal recording section spirally arranged on the optical disk. In an optical disk reproducing device having a tracking servo means for performing tracking servo control for reading by reading, detecting means for detecting that the tracking servo control does not converge, and detecting that the tracking servo control does not converge by the detecting means Then, a sensitivity increasing means for increasing the sensitivity of the servo means is provided.

[0007]

According to the present invention, when the servo control of the tracking servo device for reading the signal recorded on the spirally arranged track on the optical disk does not converge due to a change in the environment, the servo control is performed. The fact that convergence does not occur is detected by the detecting means, and the sensitivity of the servo means is increased by the sensitivity increasing means that increases the sensitivity of the servo means, so that the servo control can be easily converged.

[0008]

FIG. 1 is a block diagram showing an embodiment of the present invention. This embodiment will be described below with reference to this drawing. On the track of the optical disc 11, information to be reproduced (music information), a synchronizing signal necessary for reproducing the information, a sub-code, etc. are recorded as digital signals. This optical disc 11
Is loaded or ejected on a disc mounting portion (turntable) (not shown) by a loading mechanism (not shown) in accordance with an operation of the key operation unit 12 or the like.
The disk motor 13 drives the mounted optical disk 11 at a predetermined rotation speed. The digital signal recorded on the track of the optical disk 11 is transferred to the pickup 14
Read optically by. The digital signal read by the pickup 14 is amplified to a predetermined level by the preamplifier 15 and sent to the signal conversion circuit 16, and also to the tracking error detection unit 17, the focus error detection unit 18, the mirror detection circuit 19 and the disk rotation servo circuit 20. Is entered.

The tracking error detector 17 detects that the focus position of the reading light beam emitted from the pickup 14 is
The deviation from the inside or outside of the track of the optical disk 11 is detected from the output signal of the pickup 14 and output to the tracking servo circuit 21. The tracking servo circuit 21 is controlled in operation and non-operation by an output signal from the microcomputer 22, and in the operating state, the reading light beam follows the track of the optical disk 11 in response to the signal from the tracking error detection unit 17, A tracking actuator (not shown) is driven. Also, for a large movement that cannot be followed by the tracking actuator, the pickup feed servo circuit 23 operates in response to a signal from the tracking error detector 17, and the pickup feed mechanism (not shown) moves the pickup 14 to a predetermined position by a feed motor. To move.

The focus error detector 18 detects from the output signal of the pickup 14 that the focus position of the reading light beam is displaced upward or downward from the track of the optical disk 11, and outputs it to the focus servo circuit 24. The focus servo circuit 24 is controlled to operate or not to operate by an output signal from the microcomputer 22, and in an operating state, in response to a signal from the focus error detector 18, an unillustrated objective lens of the pickup 14 is operated by a focus actuator. Move it up and down.

The mirror detection circuit 19 includes a pickup 14
Is used to detect the focus position of the light beam read by the pickup 14, and when the focus is on the mirror surface between the tracks, it is a high level, and when it is on the track, it is a low L level (transverse The microcomputer 22 receives this output and counts the number of tracks that cross a track to a desired song during a track jump. Then, by using this crossing signal, the microcomputer 22 detects that the tracking servo device oscillates around the track and cannot follow well due to the temperature rise of the pickup 14 or secular change. That is, when the mirror detection circuit 19 outputs the cross-cut signal even after the microcomputer 22 has counted the cross-cut signal corresponding to the number of tracks after the track jump to the desired song or after a predetermined time has elapsed after the track jump is started, the tracking servo is performed. A detection means is provided for determining that the control does not converge.

The disk rotation servo circuit 20 controls the motor 13 so that the frequency of the internal reference signal and the frequency of the sync signal included in the output signal of the pickup 14 match.
Servo operation for controlling the rotation speed of the, and kick-up operation for driving the motor 13 at a predetermined rotation speed at the start of reproduction,
There are three kinds of operation states, that is, non-operation, and the operation state is switched by the microcomputer 22.

The tracking servo circuit 21 adjusts the sensitivity of the servo circuit (the feedback gain of the amplifier of the feedback circuit which constitutes the servo circuit) by the sensitivity adjustment signal from the microcomputer 22, and for example, SO
CXD2515, a digital signal processing LSI with built-in digital servo for compact disc player manufactured by NY
It can be realized by using Q etc. Therefore, the microcomputer 22 and the tracking servo circuit 21 constitute a sensitivity increasing means for increasing the sensitivity of the tracking servo means.

The signal conversion circuit 16 performs error correction and EFM demodulation processing on the signal from the pickup 14 to convert it into a digital audio signal, and outputs it to an analog circuit through a digital-analog converter (not shown). , A sub-code which is a control signal recorded by being mixed with a digital audio signal is extracted to obtain the microcomputer 22.
Output to. In addition, the signal conversion circuit 16 is the optical disc 1
An error signal is output to the microcomputer 22 when the signal cannot be read due to scratches in 1 or when the extracted subcode is abnormal.

Next, the operation of this embodiment will be described. FIG. 2 is a flow chart showing the procedure of the processing operation of the microcomputer 22. The process starts when the optical disc 11 is newly mounted or when the player operates the key operation unit 12 during the performance to instruct to move the track transversely to a desired song.

In step S1, the microcomputer 22 issues a move command to the pickup 14 according to the operation of the key operation unit 12 to start the track jump. Specifically, a signal for stopping the tracking servo operation is sent to the tracking servo circuit 21, and the pickup sending servo circuit 23 is also sent.
A signal for moving the pickup 14 is sent to. In step S2, the microcomputer 22 counts the number of traverse signals output from the mirror detection circuit 19 to the microcomputer 22, that is, the number of tracks traversed by the pickup 14, and reaches the target number (the number of tracks corresponding to the movement amount). Then step S3
Move on to. In step S3, a movement stop command for the pickup 14 is issued. Specifically, a signal for stopping the pickup feed servo circuit 23 is sent and a signal for activating the tracking servo operation is sent to the tracking servo circuit 21. However, the tracking servo control may not converge due to a change in the performance of the pickup 14 due to a temperature rise, a change over time, or the like. Therefore, in step S4, the microcomputer 22 monitors the track crossing signal to check whether the track jump really ends. That is, it is confirmed whether or not the track crossing signal is output, and if not, the process proceeds to step S5. Also,
When the track crossing signal is output, it is determined that the tracking servo control is not converged, the process proceeds to step S6, and the tracking gain is increased by one step. That is,
Raise the sensitivity of the servo means and return to step S4, and repeat this operation until the tracking servo control converges.
Gradually increase the tracking gain.

Next, at step S5, it is determined whether or not the track jump ends and the recording signal recorded on the track is read (when the focus of the pickup 14 follows the track, and when the focus is achieved, the pickup 14 is optically operated. The signal recorded on the disk 11 is output). That is, it is determined whether or not the recording signal is input to the microcomputer 22, and when the recording signal is input, step S
The process proceeds to 6 and the tracking gain is set to the original value (initial setting value), and the process is ended.

If the track crossing signal does not reach the target number even after the lapse of a predetermined time in step S2, or if the recording signal is not input to the microcomputer 22 after the lapse of the predetermined time in step S5, it is determined as an abnormality. Judgment is made and an abnormality is displayed and the processing is terminated. As described above, according to the present embodiment, when the tracking servo control does not converge due to environmental changes due to temperature rise, changes in parts over time, and the like, the tracking gain can be increased to converge the tracking servo control.

[0019]

As described above, according to the present invention, in the optical disk reproducing device, the servo control of the tracking servo device is not converged due to the change of the pickup performance due to the temperature change or the secular change. Even in this case, it is possible to raise the sensitivity of the servo means to converge the servo control and enable the reproducing operation of the optical disk reproducing device.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing a procedure of processing operation of a microcomputer according to the present invention.

[Explanation of symbols]

 11 optical disk 14 pickup 21 tracking servo circuit 22 microcomputer 23 pickup feed servo circuit

Claims (1)

[Claims] 1. A device for reproducing an optical disc, comprising:
In an optical disc reproducing apparatus having a tracking servo means for performing tracking servo control for reading a signal recorded in a signal recording section spirally arranged on the optical disc, the tracking servo control does not converge. An optical disk reproducing apparatus comprising: a detection unit for detecting the above, and a sensitivity increasing unit for increasing the sensitivity of the servo unit when it is detected by the detecting unit that the tracking servo control is not converged.