JPH0740367B2 - Optical information recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical information recording / reproducing apparatus, and more particularly to an optical information recording / reproducing apparatus having a closed loop tracking control system for driving an optical system to perform tracking correction.

[Prior Art] An optical information recording / reproducing apparatus normally records / reproduces information along a track provided on an information recording medium. Therefore, it is necessary to perform tracking control so that the light beam always follows this track. A closed loop control system is often used for this tracking control, a reflected light or a transmitted light from the information recording medium is detected, and a track error signal (hereinafter abbreviated as TES) is generated. Generally, control is performed to drive the optical system to perform tracking correction.

However, a mechanism that is usually used as a driving means of this optical system is a mechanism for electromagnetically moving a mirror or a lens by using a spring and a coil, so that there is a problem that the optical system vibrates when the carriage moves. When performing a seek operation to a specific track, it is necessary to move the carriage itself that has a built-in pickup, but in order to shorten the seek time as much as possible, the carriage movement is speed control accompanied by acceleration changes such as acceleration and deceleration. Must be done. Therefore, even if the seek operation is completed and the carriage stands still at a predetermined position, the spring built in the carriage vibrates, and accordingly, the optical system such as the mirror or the lens vibrates. If the tracking control system based on TES is operated in this state, the component based on this vibration is superimposed on TES, and of course, appropriate control cannot be performed, but on the contrary, it may interfere with the natural damping of vibration. , It may cause excessive force on the spring.

Therefore, conventionally, some methods for coping with the vibration of the optical system have been proposed. For example, the method disclosed in Japanese Patent Application Laid-Open No. 58-26331 is one in which a displacement amount sensor for detecting the vibration of the objective lens is installed in the carriage, and the vibration is controlled based on the sensor output. is there.
Further, in the method disclosed in Japanese Patent Laid-Open No. 59-84353, the optical system is vibrated by performing control such that the optical system is forcibly stopped based on the output of the photodetector while the carriage is moving. This is what you want to prevent. However,
As described above, since it is necessary to shorten the seek time and the carriage movement is accompanied by a rapid change in velocity, there is a drawback that the vibration cannot be completely suppressed by either method.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical information recording / reproducing apparatus capable of performing appropriate tracking control even if an optical system vibrates due to movement of a carriage.

SUMMARY OF THE INVENTION The present invention is an optical information recording / reproducing apparatus for irradiating a light beam on an information recording medium having a track to record information to record / reproduce information. And a carriage means that is equipped with an optical system that guides the optical recording medium and is movable in a direction crossing a track of the information recording medium, and a track error that detects a position of the light beam with respect to the track and generates a track error signal indicating a positional deviation between the two. Signal detecting means, tracking means for adjusting the optical system based on the track error signal, carriage driving means for moving the carriage, and means for monitoring the amplitude of vibration of the optical system due to the movement of the carriage. And the amplitude monitoring means monitors the amplitude of the vibration of the optical system and waits until the amplitude falls below a predetermined reference value. And a means for suppressing the operation of the tracking means.

[Embodiment] The present invention will be described below based on an illustrated embodiment. FIG. 1 is a block diagram of this embodiment. An optical disc 1 as an information recording medium is rotated by a spindle motor 2. The carriage 3 is moved by the carriage driving means 4 in the radial direction of the optical disk 1. The output of the photo detector 6 is given to the track error detection means 7, where it is calculated in a predetermined manner via a differential amplifier or the like and output as a track error signal (TES). The TES switches the control signal CS to the objective lens drive coil 9 in order to adjust the objective lens 5 in the direction of canceling the TES via the drive circuit 8.
And is tracked by a closed servo loop. However, since the switch 10 is closed during the operation of the tracking control system, the optical system is adjusted by the closed loop control system as described above, and the light beam follows the track.

Here, the tracking control operation during the seek operation will be described. The seek operation is performed by the carriage drive means 4 moving the carriage 3 to a predetermined position in response to a seek command from a host CPU (not shown) or the like. By this movement, the objective lens 5 is accelerated and decelerated when the carriage is moved as described above, and starts to vibrate. Therefore, when seeking, the upper CPU causes the carriage driving means 4 to drive the carriage 3
At the same time as issuing a command to move, the deterrent means 11 is given a signal to that effect. The inhibiting means 11 opens the switch 10 when receiving this signal. As a result, the control signal to be given to the objective lens drive coil 9 is cut off,
Tracking control by adjusting the objective lens is suppressed. The suppressing means 11 then monitors the amplitude of the vibration of the objective lens 5 by an electric signal electromagnetically induced through the coil 9, for example, until it reaches a constant reference value, that is, a value that causes no trouble even if tracking control is performed. Once damped, switch 10 is closed again. This will restart tracking control by closed loop,
It is possible to always perform appropriate tracking control.

As another means for monitoring the vibration amplitude of the objective lens 5, a displacement amount sensor for detecting the displacement amount of the optical system 5 may be provided in the carriage 3.

FIG. 2 is a configuration diagram showing one configuration of the inhibiting means 11, and FIG. 3 is an operation explanatory diagram thereof.

The input signal 31 is a signal indicating the amount of vibration of the lens, such as a signal induced in the coil 9 of the lens.

The window comparator 21 compares the input signal 31 with a preset reference signal level. The comparison output 32 is applied to the first input of the AND gate 23 via the retriggerable one-shot multivibrator 22. The lens tracking instruction signal 33 is applied to the second input of the AND gate 23. AND gate 25 has pulse 36 and A from oscillator 24
The output of the ND gate 23 and the D flip-flop 26 are input.
Output the clock. The D flip-flop 26 receives the lens tracking instruction signal 33 at the D terminal and the clear (CL) terminal. The input signal 31 may be the output of a sensor that detects the deviation of the lens.

Now, the lens tracking instruction signal 33 is generated with the completion of the movement of the carriage. Lens tracking instruction signal
A signal 33 indicates that tracking by the lens may be started, and that the movement of the carriage is stopped and the position is stabilized. Since the movement of the carriage is usually observed by an external scale such as a linear encoder, this external scale signal may be used.

On the other hand, the input signal 31, that is, the amount of vibration of the lens, is forcibly or naturally attenuated by the external means with the completion of the movement of the carriage, and exhibits a waveform as shown in FIG. input signal
31 is compared with the upper and lower limit thresholds UL and LL of the window comparator 21, and the portion exceeding the threshold is discriminated (signal 32).
The signal 32 will have a wider pulse width over time and the input signal 31
Shows that it is settling down to zero level. Input signal 32 for retriggerable one-shot multivibrator 22
In response to this, the signal of FIG. 34 is output. The signal 34 indicates that the input signal 31, that is, the vibration of the lens has fallen below a certain amount.

Since AND gate 23 uses signals 33 and 34 as input signals,
The output 35 represents a state where both the condition that the carriage is stopped and the condition that the vibration of the lens is stopped are satisfied. Output 35 is pulsed through AND circuit 25 with pulse 36 (signal 37) before being applied to the clock terminal of D flip-flop 26. Therefore, the Q output 38 of the flip-flop 26 rises in a state where the vibration of the lens is sufficiently suppressed, and the switch 10 that has been opened at the start of the seek operation is closed again, and the tracking operation by the tracking servo loop is restarted.

It should be noted that although the above embodiments have been described as if they had an independent circuit configuration as the suppressing means, it is common to give the function to the controller section of a so-called optical information recording / reproducing apparatus, and it is easily replaced by the configuration by the CPU. It is what is done. In this case, the function described as the switch in the above embodiment is configured by the gate provided in the CPU, the switching transistor, or the like.

Further, the flip-flop means is not limited to the D-type flip-flop, but can be replaced by other various logic circuits having a hold function.

[Advantages of the Invention] As described above, according to the present invention, in an optical information recording / reproducing apparatus having a tracking control system for adjusting an optical system, tracking is performed until the amplitude of vibration of the optical system falls below a certain reference value. Since the control operation is suppressed, appropriate tracking control can be performed even if the optical system vibrates due to the movement of the carriage.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of the configuration of the suppressing means of the embodiment, and FIG.
It is operation | movement explanatory drawing of the circuit diagram shown in a figure. 1 ... Optical disk 2 ... Spindle motor 3 ... Carriage 4 ... Carriage drive means 5 ... Optical system 6 ... Photodetector 7 ... Track error detection means 8 ... Drive circuit 9 ... Optical system drive coil 10 ... Switch 11 ... deterrent

Claims (1)

[Claims] 1. An optical information recording / reproducing apparatus for irradiating an information recording medium having a track to record information with a light beam to record / reproduce information, an optical system for guiding the light beam to the information recording medium. Carriage means for mounting the carriage, which is movable in a direction crossing a track of the information recording medium, and track error signal detecting means for detecting a position of the light beam with respect to the track and generating a track error signal indicating a displacement between the two. Tracking means for adjusting the optical system based on the track error signal, carriage driving means for moving the carriage, means for monitoring the amplitude of vibration of the optical system due to the movement of the carriage, and the amplitude The monitoring means inspects the amplitude of the vibration of the optical system, and the tracker is monitored until the amplitude falls below a predetermined reference value. The optical information recording and reproducing apparatus comprising: an inhibiting means for inhibiting the operation of the unit.