JPH097190A - Optical information recording / reproducing device - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the tracking error signal and focus error signal from increasing during acceleration and deceleration of ultrasonic motors. A movable head 104 for irradiating a light beam to the optical card 100, a voice coil motor 113 for relatively reciprocating the optical card and the movable head in the track direction,
The tracking control loop and the ultrasonic motor 21 for relatively moving the movable head and the optical card in the direction orthogonal to the track.
And a subtractor 51 for applying the correction signal to a tracking control loop, and a means for generating a correction signal for correcting a tracking error signal at the time of acceleration / deceleration of a voice coil motor or an ultrasonic motor. The tracking error signal is corrected by applying the correction signal to the tracking control loop in synchronization with the start and stop of driving of the coil motor or the ultrasonic motor.
Further, a correction signal is applied to the focus control loop to correct the focus error signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus for optically recording information on an information recording medium or reproducing the recorded information.

[0002]

2. Description of the Related Art Conventionally, various types of information recording media for optically recording and reproducing information have been known, such as disk-shaped, card-shaped and tape-shaped. Among them,
A card-shaped recording medium (hereinafter referred to as an optical card) has excellent productivity, portability, and accessibility, and is compact, lightweight, and has a large storage capacity, so it is expected that its applications will continue to expand in the future. There is. Generally, when a light beam is scanned on such an optical card, the optical card and the light beam are relatively moved back and forth in the information track direction,
A method of scanning a light beam on an information track of an optical card is adopted.

As a device for relatively scanning the optical card and the light beam, there is, for example, a device as filed in Japanese Patent Application No. 5-289805. That is, a voice coil motor is used to reciprocally move the optical head in the track direction to scan the light beam on the information track, and a shuttle having an optical card mounted thereon is driven in the above-described scanning direction by driving the ultrasonic motor. By moving in the orthogonal direction, the light beam is moved in the cross-track direction.

FIG. 9 is a block diagram showing such an optical information recording / reproducing apparatus. FIG. 9 shows the tracking control loop, the objective lens position control loop, and the drive circuit of the shuttle for mounting the optical card. In FIG. 9, 1a and 1c are photodetectors for tracking control, and the detection signals of these two photodetectors are fed to the differential amplifier 2
A tracking error signal is generated by differentially detecting at. Tracking error signal is comparator 1
It is binarized by 0 and taken into the MPU 5, and is output to the tracking control loop to perform tracking control of the light spot emitted from the optical head. That is, the tracking control loop is configured by the components from the photodetectors 1a and 1c to the differential amplifiers 2 and 3, the phase compensator 6, the changeover switch 22, the AT (auto tracking) coil driver 7, and the AT coil 8. In this control loop, the objective lens 9 is slightly moved in the tracking direction so that the tracking error signal becomes 0, whereby tracking control is performed so that the light spot does not deviate from the information track.

The lens position sensors 11a and 11b are sensors for detecting the position of the objective lens 9 in the tracking direction, and the lens position signal is generated by differentially detecting the detection signals of these sensors by the differential amplifier 12. . That is, a reflecting plate is attached to the side surface of the lens barrel of the objective lens 9, and light is emitted from the light emitting element provided on the apparatus body side, and the reflected light from the reflecting plate is reflected by the lens position sensor 1.
It is detected by 1a and 11b. Therefore, the position sensor 11
Since the light receiving amounts of a and 11b change according to the position of the objective lens 9 in the tracking direction, differential detection of these detection signals by the differential amplifier 12 results in a lens position corresponding to the position of the objective lens 9 in the tracking direction. You can get a signal. This lens position signal is sent to the A / D converter 13
It is taken into PU5.

Further, the position control loop of the objective lens 9 is constituted by the components from the lens position sensors 11a and 11b to the differential amplifiers 12 and 23, the phase compensator 24, the changeover switch 22, the AT coil driver 7 and the AT coil 8. Has been done. The position control loop and the tracking control loop are switched by the changeover switch 22 under the control of the MPU 5.

Next, the shuttle drive circuit will be described. 14 is a D / A for applying an analog voltage to a voltage controlled oscillator (VCO) 15 based on an instruction from the MPU 5.
It is a converter. The VCO 15 performs voltage / frequency conversion that changes the frequency of the output signal in accordance with the input voltage, and outputs the output signal fd having the frequency corresponding to the input voltage as shown in FIG. The output signal of the VCO 15 is output to the ring counter 17, which divides the output signal fd by 4 and divides the divided signal into 4 sets of signals. The output is shifted by 90 degrees. In this way, the signals whose phases are shifted by 90 degrees are A ₁ , A ₂ and B.
₁ and B ₂ are output to the changeover switch 18. The changeover switch 18 has an ON / OFF signal indicating whether to drive the ultrasonic motor 21 from the MPU 5 or to stop the ultrasonic motor 21, and an FWD / to indicate a rotation direction of whether the ultrasonic motor 21 is normally rotated or reversely rotated. The REV signal is input.

The changeover switch 18 instructs the ultrasonic motor 21 to be driven by these signals, and selectively outputs four output signals of the ring counter 17 so as to rotate in the instructed direction. 10B to 10E show output signals C, D, E, and F of the changeover switch 18 when the ultrasonic motor 21 is rotated in the forward direction. The signal thus selected according to the rotation direction is output to the drive circuit 19 as a drive phase output. The drive circuit 19 performs power amplification and the like based on these signals, and boosts the voltage with the booster coil 20. The sinusoidal drive signals G and H having phases shifted by π / 2 as in 10 (f) and 10 (g) are generated and applied to the ultrasonic motor 21. Ultrasonic motor 21
Is a motor that drives the shuttle on which the optical card is placed in a direction orthogonal to the track.When the optical head accesses a desired track or the optical card has a skew, the shuttle is moved in the direction orthogonal to the track. By moving it, the light spot is moved to a target track, and correction control for skew is performed so that the center of the objective lens 9 is located at the center of the track.

Here, when the light spot is to access a desired track, the switch piece x of the changeover switch 22 is turned off and the switch piece y is turned on. In this state, the optical card is placed by driving the ultrasonic motor 21. The shuttle is moved, which causes the light spot to move toward the target track. When the light spot approaches the target track, the driving of the ultrasonic motor 21 is stopped and the MPU 5 causes the D / A
The drive signal of the objective lens 9 is supplied to the differential amplifier 23 via the converter 25. As a result, the objective lens 9 is driven, and the light spot further moves to the target track accordingly. At this time, the MPU 5 takes in a signal obtained by binarizing the tracking error signal when the light spot traverses the track by the comparator 10, and when detecting that the light spot is located on the target track from the binarized signal, The switch piece x of the changeover switch 22 is turned on and y is turned off to turn on the tracking control loop. In this way, the light spot is drawn into the target track, and thereafter, the target track is scanned by tracking control to record or reproduce information. When the light spot is jumped to the adjacent track, the jump pulse is supplied from the MPU 5 to the differential amplifier 3 via the D / A converter 4. By thus supplying the jump pulse and driving the objective lens 9, the light spot jumps to the adjacent track, and recording or reproduction is performed on the adjacent track.

Next, the control operation when the shuttle is moved in the direction orthogonal to the track when the optical card has a skew will be described with reference to FIG. FIG. 11A shows a differential amplifier 12 which detects detection signals from the lens position sensors 11a and 11b.
Is a lens position signal of the objective lens 9 obtained by differential detection at, p is a center position of the objective lens 9, and m is a limit point of a movable range of the objective lens 9. That is, the objective lens 9 has a movable range so as to be movable in a predetermined range in the left and right tracking directions from its center, and m is one movable limit point in the left and right tracking directions. Here, FIG.
The lens position signal of (a) is taken into the MPU 5, and the position of the objective lens 9 in the tracking direction is constantly monitored by the MPU 5.

In the MPU 5, when the objective lens 9 reaches the movable limit point m due to skew of the optical card or the like during tracking control, at the reached q ₁ , an instruction to drive the ultrasonic motor 21 is given as shown in FIG. 11B. The signal is output to the changeover switch 18. Of course, at the same time, a signal instructing the rotation direction of the ultrasonic motor 21 according to the moving direction of the objective lens 9 in the tracking direction is also output. As a result, the ultrasonic motor 21 starts rotating in the instructed direction, the shuttle on which the optical card is placed moves in the direction orthogonal to the track, and control is performed so that the objective lens 9 moves toward its center position. Be seen. The objective lens 9 is shown in FIG.
Returning to q ₂ near its center as in (a), M
An off signal is output from the PU 5 to the changeover switch 18 as shown in FIG. 11B, and the driving of the ultrasonic motor 21 is stopped. In this way, the objective lens 9 is controlled so as to return to the substantially central position of the optical head, and the correction control of the positional relationship between the optical spot irradiated on the optical card and the information track is performed.

[0012]

By the way, in the optical information recording / reproducing apparatus of FIG. 9, an ultrasonic motor is used as a means for moving the shuttle in the track crossing direction. Such an ultrasonic motor is started. And the stopping performance is very good. Therefore, FIG.
Assuming that the ultrasonic motor is started at q ₁ point and stopped at q ₂ point as in (a) and (b), it will start abruptly at that q ₁ point and stop abruptly at q ₂ point. A phenomenon that the tracking error signal increases at the starting point and the stopping point as shown in 11 (c) occurs. This occurs because the acceleration at the time of starting and stopping is large, and when the tracking error signal becomes large in this way, the optical spot may be displaced due to the tracking error and adversely affect the recording / reproduction, or the tracking error may occur. There was a risk of disconnection.

In view of the above conventional problems, the present invention applies optical signals to a tracking control loop by applying a correction signal for correcting the tracking error signal to cancel the increase in the tracking error signal. An object is to provide a recording / reproducing device.

Further, the present invention provides an optical information recording / reproducing apparatus which cancels an increase in the focus error signal by applying a correction signal for correcting the focus error signal to the focus control loop. The purpose is to

[0015]

An object of the present invention is to provide an optical head for irradiating an information recording medium with a light beam and a first optical head for reciprocating the optical head and the recording medium in the information track direction. Driving means, a tracking control loop for controlling the tracking of the light beam of the optical head, and a second driving means for moving the optical head and the recording medium relatively in the direction orthogonal to the information track. In the optical information recording / reproducing apparatus having the following: correction signal generating means for generating a correction signal for correcting the tracking error signal at the time of acceleration / deceleration of the first or second driving means, and correction of the correction signal generating means A correction signal applying unit for applying a signal to the tracking control loop, the driving unit being synchronized with the start and stop of driving of the first or second driving unit. By applying a correction signal to the tracking control loop is achieved by an optical information recording and reproducing apparatus characterized by correcting the tracking error signal during acceleration or deceleration of the first or second driving means.

Another object of the present invention is an optical head for irradiating an information recording medium with a light beam, and a first driving means for relatively reciprocating the optical head and the recording medium in the information track direction. An optical system having a focus control loop for controlling the focus of the light beam of the optical head, and a second drive means for relatively moving the optical head and the recording medium in a direction orthogonal to the information track. In the information recording / reproducing apparatus, a correction signal generating means for generating a correction signal for correcting a focus error signal at the time of acceleration / deceleration of the first or second driving means, and a correction signal of the correction signal generating means for the focus signal. The focus control is provided in synchronization with a driving start and a driving stop of the first or second driving means, which comprises a correction signal applying means for applying to a control loop. By applying a correction signal to-loop is achieved by an optical information recording and reproducing apparatus characterized by correcting the focus error signal during acceleration or deceleration of the first or second driving means.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, a first embodiment of the present invention will be described. FIG. 1 is a diagram showing the overall configuration of the optical information recording / reproducing apparatus of the first embodiment. In FIG. 1, 100
Is an optical card, which is an information recording medium, and is placed on the shuttle 101. The shuttle 101 drives the optical card 100 by driving the ultrasonic motor 21 as described above.
Of the optical card 100 so that the light spot can access a desired track of the optical card 100. If the optical card 100 has a skew or the like, the shuttle 101 is driven to perform correction control for the skew so that the objective lens 9 is returned to the center of the optical head. The ultrasonic motor 21 is in pressure contact with the guide plate 102 and is in contact with the shuttle 101, and the driving force of the ultrasonic motor 21 is transmitted to the shuttle 101 by this structure. In addition, the ultrasonic motor 21
Is controlled by the shuttle drive circuit 103 based on an instruction from the MPU 5. The shuttle drive circuit 103 will be described later in detail.

On the upper surface of the optical card 100, the optical card 10
An optical head for irradiating a recording / reproducing light beam is arranged at 0. The optical head includes a movable head 104 and a fixed head 105. Inside the fixed head 105, a semiconductor laser 106 as a light source, a photodetector 107 for detecting reflected light from the optical card 100, and the like are provided. The photodetector 107 is composed of photodetectors for information reproduction, focusing, and tracking as will be described later, and the photodetectors 1a and 1c shown in FIG. 9 are included therein. On the other hand, in the movable head 104, the objective lens 9 that focuses the light beam of the semiconductor laser 106 into a minute light spot and irradiates the optical card 100, the AT coil 8 that drives the objective lens 9 in the tracking direction, and the objective lens 9 in the focus direction An AF (autofocus) coil 108 to be driven and lens position sensors 11a and 11b for detecting the position of the objective lens 9 in the tracking direction are provided.

A semiconductor laser 106 in the fixed head 105.
Is controlled by the laser drive circuit 109 based on an instruction from the MPU 5, and at the time of recording information, the information is recorded by intensity-modulating the light beam by a predetermined modulation method. At the time of reproducing information, the light beam of the semiconductor laser 106 is controlled to have a low power that cannot be recorded. The detection signal of the photodetector 107 in the fixed head 105 is the AT / AF control circuit 1
10 and the AT / AF control circuit 110 controls the AT coil 8 and the AF coil 108 on the basis of the detection signal to displace the objective lens 9 in the tracking direction and the focus direction, thereby performing tracking control and focus control. Is done. In the reproducing circuit 111, the recorded information is reproduced based on the detection signal of the photodetector 107, and MP
At U5, the reproduction signal is subjected to predetermined signal processing to generate reproduction data.

In the lens position detection circuit 112, the objective lens 9 is detected based on the detection signals of the lens position sensors 11a and 11b.
Position in the tracking direction is detected, and the detection result is MP
Captured by U5. The movable head 104 is driven by a magnetic circuit including a voice coil motor 113 and a magnet 114 so as to reciprocate in the track direction of the optical card.
00 relatively reciprocates in the track direction, and the light spot scans the information track. The voice coil motor 113 is controlled by the head drive circuit 115 based on an instruction from the MPU 5.

FIG. 2 shows the movable head 104 and the fixed head 10.
FIG. 6 is a diagram showing a specific configuration of the optical head composed of 5;
In FIG. 2, first, a semiconductor laser 106 is provided in the fixed head 105, a divergent light beam emitted from the semiconductor laser 106 is collimated by a collimator lens 120, and a predetermined light intensity distribution is obtained by a light beam shaping prism 121. Is shaped into The light beam emitted from the light beam shaping prism 121 is split into three light beams of the 0th-order light beam and the ± 1st-order light beam by the circular grating 122, and the respective divided light beams are transmitted through the polarization beam splitter 123. Then
Further, the light is reflected by the reflection prism 124 in the movable head 104 and guided to the objective lens 9. Then, the three light beams are respectively condensed by the objective lens 9 and imaged on the optical card 100 as minute light spots S1, S2 and S3. S1 is ± 1 next time, S2 is 0 next time, S3 is-
It is the light spot of 1 next time.

The light spots S1 and S3 are irradiated so that a part thereof is applied to the tracking track of the optical card 100 as shown in the enlarged view in the figure, and the light spot S2 is located on the information track between the tracking tracks. Is illuminated. The reflectance of the tracking track is lower than that of the information track, and the light spot S1 ~
When S3 has a track deviation in either direction,
Photodetector 1a for detecting the return light of the light spots S1 and S3
An imbalance occurs in the detection signals of 1 and 1c. That is, FIG.
As described above, by differentially detecting the detection signals of the photodetectors 1a and 1c, a tracking error signal indicating the amount and direction of deviation of the light spot with respect to the track is generated. Then, based on this tracking error signal, the AT coil 8 shown in FIG.
By slightly moving in the tracking direction (Y direction), tracking control is performed so that the information recording / reproducing light spot S2 does not deviate from the information track.

The three light spots applied to the optical card 100 are reflected by the surface of the optical card, pass through the objective lens 9 and are returned to parallel light again. In addition, the reflection prism 12
The beam is guided to the polarization beam splitter 123 via 4 and further focused by the focusing lens system 125 to enter the photodetector 107. The photodetector 107 is composed of photodetectors 1a and 1c and a four-divided photodetector 1b provided therebetween. Among them, the photodetectors 1a and 1c are for tracking control and the photodetection 1b is for focusing as described above. Used for control and information reproduction. The detection signal of the light detection 1a-1c is AT /
It is output to the AF control circuit 110, and tracking control is performed based on the tracking error signal as described above. Further, in the AT / AF control circuit 110, the photodetector 1b
Focus error signal is generated based on the detection signal of
Focus control is performed by controlling the AF coil 108 based on this signal.

FIG. 3 is a block diagram showing the configuration of the main part of the optical information recording / reproducing apparatus of this embodiment. In FIG. 3, the same parts as those of the conventional device of FIG. 9 are designated by the same reference numerals and detailed description thereof will be omitted. In FIG. 3, 1a and 1c are photodetectors for tracking control, and 2 is these photodetectors 1a and 1
It is a differential amplifier that generates a tracking error signal by differentially detecting the detection signal of c. This photodetector 1a,
1c, differential amplifier 2 and differential amplifier 3, phase compensator 6,
The tracking control loop is configured by the constituent elements such as the changeover switch 22, the AT coil driver 7, and the AT coil 8. The components of the above tracking control loop are provided in the AT / AF control circuit 110 of FIG. Although a focus control loop is not shown in FIG. 3, a focus control loop is provided in the AT / AF control circuit 110, and focus control is performed so that the light spot focuses on the optical card surface.

Further, in this embodiment, a subtractor 50 is provided between the differential amplifier 2 and the differential amplifier 3. MPU5
Inputs a correction signal to one input terminal of the subtractor 50 via the D / A converter 51, and thereby a correction signal for correcting the increment of the tracking error signal is applied to the tracking control loop. That is, since the tracking error signal increases as described above when the ultrasonic motor 21 is started and stopped, the correction signal is applied to the tracking control loop in synchronization with the start and stop of the driving of the ultrasonic motor 21, and the subtraction is performed. The subtracter 50 subtracts the correction signal from the tracking error signal to cancel the increase in the tracking error signal.

The EEPROM 52 is a non-volatile memory for storing this correction signal, and is digitized in time series in order from a predetermined head address in response to start and stop of driving of the ultrasonic motor 21. The correction signal is stored. As the correction signal at this time, for example, the value of the correction signal is determined by driving the ultrasonic motor 21 at the time of assembly and adjustment of the apparatus and measuring the tracking error signal at that time. Further, it is not limited to this, and it can be determined by calculation or the like. The D / A converter 51 is of a type that holds the current signal value until the next signal is transferred.
The correction signal read out sequentially from the head address of the PROM 52 and transferred at every predetermined time interval Δt is converted into an analog signal and output to the subtractor 50.

The lens position sensors 11a and 11b detect the position of the objective lens 9 in the tracking direction as in FIG. 9, and the detection signal is differentially detected by the differential amplifier 12 to generate a lens position signal. To be done. The lens position signal is taken into the MPU 5 by the A / D converter 13. Further, the lens position signal is output to the phase compensator 24, the AT coil driver 7, and the AT coil 8 via the differential amplifier 23, and the position control loop of the objective lens 9 controls the position of the objective lens 9. As described above, the tracking control loop and the position control loop are MPUs.
It is switched by the changeover switch 22 based on the instruction of 5. Further, the D / A converter 14, the VCO 15, the ring counter 17, the changeover switch 18, the drive circuit 19
9 is the same as FIG. 9, and these circuits constitute a shuttle drive circuit for driving the ultrasonic motor 21 to move the shuttle in the direction orthogonal to the information track.
The shuttle drive circuit is provided in the shuttle drive circuit 103 of FIG.

Next, the operation of the above embodiment will be described with reference to FIG. First, when recording or reproducing information, the movable head 104 is reciprocally moved in the track direction by the driving of the voice coil motor 113, and the light spot and the optical card are relatively reciprocating. At this time, the light spot from the movable head 104 is controlled by the functions of the tracking control loop and the focus control loop so as to follow the information track for scanning and keep the in-focus state on the card surface.

In such a state, the optical card 100
If there is a skew, the tracking control is working, and the objective lens 9 follows the skew and moves in the tracking direction. Objective lens 9 at this time
The position in the tracking direction is detected by the lens position sensor 11 and is output as a lens position signal as shown in FIG. The lens position signal is a signal obtained by differentially detecting the detection signal of the lens position sensor 11 with the differential amplifier 12. In FIG. 4A, p is the center position of the movable range of the objective lens 9 (center position of the objective lens 9), and m is one limit point of the left and right movable range in the tracking direction. The movable range of the objective lens 9 is determined by the mechanical condition of the tracking actuator and the condition of the optical system, and has a movable range of, for example, about ± 100 μm.

The lens position signal of FIG. 4 (a) is taken into the MPU 5 by the A / D converter 13, and the objective lens 9 in the MPU 5 moves following the skew, and eventually the objective lens 9 moves as shown in FIG. 4 (a). When it moves to the limit point m of the range, at the point q ₁ at which the limit point m is reached, as shown in FIG.
The ON signal for instructing the driving of is output. Of course, M
The PU 5 recognizes the moving direction of the objective lens 9 based on the lens position signal, and accordingly outputs the FWD / REV signal indicating the rotating direction of the ultrasonic motor 21 to the changeover switch 18. The FWD signal is output when instructing forward rotation, and the REV signal is output when instructing reverse rotation.

In this way, the ultrasonic motor 21 is driven, the shuttle 101 on which the optical card 100 is placed starts moving in the direction orthogonal to the track, and the tracking control works in accordance with this movement, so that the objective lens 9 is It returns to the center of the movable head 104 as shown in FIG. On the other hand, M
At the same time that the PU5 outputs the ON signal as shown in FIG. 4B, the reading of the correction signal from the EEPROM 52 is started, and the correction signals are sequentially read from the head address and output to the D / A converter 51 at a predetermined time interval Δt. Go. This correction signal is sequentially converted into an analog signal by the D / A converter 51 and output to the subtractor 50. In this way, the correction signal is applied to the tracking control loop.

W _{1 in} FIG. 4C shows a correction signal after being converted into an analog signal by the D / A converter 51 at this time, and as described above, the correction signal is output at Δt intervals. It has a stepwise waveform as shown in FIG. Points indicate data points. D in the subtractor 50
When the correction signal is output from the A / A converter 51, the correction signal is subtracted from the tracking error signal of the differential amplifier 2, and the correction signal is subtracted from the tracking error signal in this way, thereby increasing the increase in the tracking error signal. Offset. The tracking error signal after this correction is output to the tracking control loop after the differential amplifier 3 in the next stage. The signal shown by the solid line in FIG. 4D shows the tracking error signal after correction by the subtractor 50, and the signal shown by the broken line shows the tracking error signal before correction. The error signal becomes almost 0, and the ultrasonic motor 21
It can be seen that the increase in the tracking error signal at the start of is completely offset.

When the objective lens 9 returns to approximately the center of the movable head 104, the MPU 5 switches to the changeover switch 18 as shown in FIG.
The off signal is output as shown in FIG.
Stop driving. Simultaneously with the output of the OFF signal, the MPU 5 outputs the correction signals of the EEPROM 52 in order from the predetermined head address to the D / A converter 51 at Δt intervals.
Output to. The correction signal at this time is the ultrasonic motor 2
The correction signal corresponds to the driving stop of No. 1 and has a polarity opposite to that of the correction signal at the start of driving according to the polarity of the tracking error signal as shown in FIG. Then, the D / A converter 51 converts the correction signal into an analog signal, and the subtractor 50 similarly subtracts the correction signal from the tracking error signal to correct the tracking error signal. Also in this case, as shown in FIG. 4D, the increase in the tracking error signal when the drive of the ultrasonic motor 21 is stopped is offset, and the tracking error signal becomes almost zero.

In this embodiment, the correction signal is stored in the EEPROM 52 in advance, and the correction signal is applied to the tracking control loop in synchronization with the start and stop of the driving of the ultrasonic motor 21. It is possible to cancel the increase in the tracking error signal generated during deceleration. Therefore, when the ultrasonic motor 21 is accelerated or decelerated, the light spot will not be displaced or the tracking will not be lost, and the operation of the apparatus can be stabilized.

In the embodiment, the subtractor is used to apply the correction signal to the tracking control loop, but an adder may be used. In this case, as shown by W ₂ in FIG. 4C, the correction signal stored in the EEPROM 52 has a polarity opposite to that of the tracking error signal, and this is added to the tracking error signal by using an adder. Then, the increase in the tracking error signal may be offset. Further, in the embodiment, an example in which the tracking error signal at the time of acceleration / deceleration of the ultrasonic motor 21 is corrected when the optical card has a skew has been described. Sound wave motor 2
It goes without saying that increase in the tracking error signal during acceleration / deceleration of 1 can be prevented.

FIG. 5 is a block diagram showing the structure of the main part of the second embodiment of the present invention. In FIG. 5, the same parts as those in FIG. 3 of the first embodiment are designated by the same reference numerals. In this embodiment, the D / A converter 51 for converting the correction signal of the EEPROM 52 into an analog signal is used as a jump pulse conversion D.
The / A converter 4 is also used, and the subtracter 50 for applying the correction signal to the tracking control loop is also used for the jump pulse applying differential amplifier 3. EEPROM5
In the same manner as in the previous embodiment, 2 stores correction signals when the ultrasonic motor 21 is driven and when it is stopped, in the order of addresses. Other configurations are the same as those in FIG.

When the objective lens 9 moves to the limit point m of the movable range due to the skew of the optical card as shown in FIG. 6A, the MPU 5 instructs the changeover switch 18 to drive the ultrasonic motor 21. The signal is output. At the same time, the MPU 5 reads out the correction signals from the EEPROM 52 in the order of addresses, and outputs the correction signals at a predetermined time interval Δt.
It is transferred to the / A converter 4. The transferred correction signal is converted into an analog signal by the D / A converter 4 as shown in FIG. 6C, and is output to the inverting input terminal of the differential amplifier 3 which is the target point of the tracking control loop. This allows
In the differential amplifier 3, the correction signal and the tracking error signal are differentiated, and the increase in the tracking error signal is canceled as shown in FIG. Further, when the objective lens 9 returns to the approximate center of the movable head 104, the MPU 5 causes the movable head 104 to move to the position in FIG.
At the same time when the OFF signal is output as in (b), EEPRO
The correction signal of M52 is sequentially transferred to the D / A converter 4 at a predetermined time interval Δt. As a result, the correction signal is D /
It is converted into an analog signal by the A converter 4 as shown in FIG. 4C, and is output to the inverting input terminal of the differential amplifier 3. Therefore, also in this case, the differential between the tracking error signal and the correction signal is taken, and the increase in the tracking error signal is canceled as shown in FIG. 6D.

As described above, also in this embodiment, similarly to the previous embodiment, it is possible to prevent the tracking error signal from increasing when the ultrasonic motor 21 is accelerated or decelerated, and the light spot is displaced to adversely affect the recording and reproduction. Moreover, it is possible to prevent the occurrence of tracking error. Also,
Since the correction signal is applied using the jump pulse applying D / A converter 4 and the differential amplifier 3, there is no need to provide a new D / A converter or subtractor, and the configuration is simpler than that of the first embodiment. Can be converted.

FIG. 7 is a block diagram showing the construction of the main part of the third embodiment of the present invention. In FIG. 7, the same parts as those in FIG. 3 of the first embodiment are designated by the same reference numerals. In this embodiment, a correction signal generating circuit for generating a correction signal of a tracking error signal is provided in the device, and the obtained correction signal is stored in a memory and used for correcting the tracking error signal during operation of the device. Is. The correction signal generating circuit includes an A / D converter 53 and MPU5,
The ultrasonic motor 21 is actually driven to measure the level of the tracking error signal during acceleration / deceleration.

More specifically, with the light spot scanning the track, the MPU 5 changes the switch 1
An ON signal is output to 8 to test drive the ultrasonic motor 21. At this time, the D / A converter 51 is in the neutral state and the tracking error signal is not corrected. When the ultrasonic motor 21 is driven in this way, the A / D
The tracking error signal of the differential amplifier 2 is taken into the MPU 5 by the converter 53 at every predetermined time interval Δt, and is sequentially stored in order from the head address of the RAM 54. That is, the level of the tracking error signal at the start of driving the ultrasonic motor 21 is measured at predetermined time intervals Δt and stored in the RAM 54. Ultrasonic motor 2
When a predetermined time has elapsed from the start of driving of 1 and the tracking error signal becomes 0 level, the level of the tracking error signal when the driving of the ultrasonic motor 21 is stopped is measured. That is, the MPU 5 outputs an off signal to the changeover switch to stop the driving of the ultrasonic motor 21. At the same time as this driving is stopped, the tracking error signal is taken into the MPU 5 at predetermined time intervals Δt by the A / D converter 53, and RA
The data is stored in M54 in order in time series. This completes the creation of the correction signal.

The correction signal as described above may be created when the optical card is inserted into the apparatus and becomes ready for recording and reproduction, and thereafter, it may be periodically executed at predetermined intervals. Good. Of course, it may be performed each time the optical card is loaded into the device. Further, in the embodiment, the RAM 54 is used as a memory for storing the correction signal. However, since the correction signal is created and stored in the operation state of the apparatus, the RAM 54 is not the nonvolatile memory as in the previous embodiment.
This is because a volatile memory is sufficient.

Further, in FIG. 7, the D / A converter 5
1. The subtractor 50 is the same as that of FIG. 3, and is used for converting the correction signal into an analog signal and applying it to the tracking control loop. Other configurations are the same as those in FIG. The correction operation of the tracking error signal is shown in FIGS.
Since it is exactly the same as the embodiment described above, it will be briefly described. However, when the objective lens 9 moves to the limit point of the movable range due to a skew or the like during the normal operation of the apparatus, the MPU 5 is switched as shown in FIG. 4B. An ON signal is output to the switch 18, and the ultrasonic motor 21 is driven. At the same time M
The PU 5 sequentially outputs the correction signals of the RAM 54 to the predetermined time interval Δt.
Then, the signal is transferred to the D / A converter 51, and the correction signal as shown in FIG. As a result, the subtractor 50 subtracts the correction signal from the tracking error signal to cancel out the increase in the tracking error signal when the ultrasonic motor 21 is started. Further, when the objective lens 9 returns to the approximate center of the movable head 104, as shown in FIG.
An off signal is output from PU5, and driving of the ultrasonic motor 21 is stopped. At the same time, RAM54 in MPU5
4 is sequentially transferred to the D / A converter 51 at a predetermined time interval Δt, and the correction signal as shown in FIG.
Output to 0. Therefore, also in this case, the correction signal is subtracted from the tracking error signal, and the increase in the tracking error signal is offset.

In this embodiment, it is possible to prevent the tracking error signal from increasing when the ultrasonic motor 21 is accelerated or decelerated, just as in the previous embodiments. Further, in the present embodiment, since the correction signal is obtained by actually driving the ultrasonic motor 21 as a test and measuring the tracking error signal at that time, variations in the driving characteristics of the ultrasonic motor 21 and changes over time will occur. Even if there is, an appropriate correction signal can be obtained according to those changes, so that the tracking error signal can be corrected more accurately.

FIG. 8 is a block diagram showing a fourth embodiment of the present invention. In the third embodiment, the correction is performed by measuring the tracking error signal, but in the present embodiment, the correction signal is created by the arithmetic processing. More specifically, the EEPROM 52 is a non-volatile memory, and the transfer characteristic data of the tracking control loop is stored in advance. Before driving the ultrasonic motor 21 in the MPU5, EE
A correction signal is obtained by calculation based on the characteristic data of the PROM 52 and stored in the RAM 54. The process of obtaining the correction signal is performed, for example, when the device is started up or when an optical card is inserted into the device. Also, the subtractor 50,
The D / A converter 51 is the same as that of FIGS.

Next, a method of calculating the correction signal will be described. When calculating the correction signal, first the tracking (AT) is calculated from the open loop transfer characteristic of the tracking control loop.
The error displacement is calculated. That is, AT error displacement = 1 / (1 + AT open loop transfer function) is obtained. Next, a step response is obtained from the obtained AT error displacement, and the AT speed step response, which is a correction pattern signal, is obtained by differentiating the step response.
That is, the correction signal is obtained as follows.

Correction pattern signal = AT speed step response = d / dt (AT error step response) The obtained calculation result is stored in the RAM 54, and in this case also, at the start and stop of the drive of the ultrasonic motor 21, The respective correction signals are stored in the RAM 54 in time series in the order of addresses.

Next, during the normal operation of the apparatus, the correction signals in the RAM 54 are sequentially output at predetermined time intervals Δt in synchronization with the driving start of the ultrasonic motor 21 in the same manner as in the previous embodiment. Transfer to. As a result, the correction signal is converted into an analog signal as shown in FIG.
By outputting this to the subtractor 50, the increment of the tracking error signal is offset. In addition, the ultrasonic motor 21
The correction signals of the RAM 54 are sequentially transferred to the D / A converter 51 at a predetermined time interval Δt in synchronization with the driving stop.
Also in this case, the correction signal is output from the D / A converter 51 as shown in FIG.
By converting to an analog signal as shown in (c) and outputting this to the subtractor 50, similarly, the increment of the tracking error signal is canceled.

Also in this embodiment, as in the previous embodiment, the increase in the tracking error signal generated during the acceleration / deceleration of the ultrasonic motor 21 can be offset, and the operation of the apparatus can be stabilized. Further, in this embodiment, since the correction pattern signal is obtained by calculation, it is not necessary to measure the tracking error signal when the optical card is inserted to create the correction signal, and the adjustment time of the device can be shortened. Further, in the present embodiment, the calculation process for obtaining the correction pattern signal is performed by the MPU 5, but it is possible to speed up the calculation process by using a dedicated processor for calculation. Therefore, in this case, since the correction pattern signal can be calculated in real time by the processor and transferred to the D / A converter 51, it is not necessary to perform the calculation processing in advance to store the data in the memory, and the RAM 54 can be deleted. it can.
Also, in the embodiments of FIGS. 7 and 8, the correction signal may be applied to the tracking control loop by using the adder as described in FIG.

In the above embodiment, the ultrasonic motor 2
Although the example of correcting the tracking error signal when the light spot is moved in the direction orthogonal to the track by driving 1 has been described, the present invention can also correct the focus error signal. That is, if the center of gravity of the movable head 104 is not balanced with respect to the direction orthogonal to the track, the focus error signal may increase during deceleration of the ultrasonic motor 21 to cause defocus. Therefore, in such a case, the increase in the focus error signal can be offset by applying the correction signal to the focus control loop in synchronization with the start and stop of the driving of the ultrasonic motor 21.

Further, in the embodiment, an example in which the optical card and the movable head move relative to each other in the direction perpendicular to the track has been shown, but the present invention also applies to the case where the optical card and the movable head move relative to the track. It is possible to apply. That is, the movable head 104 of FIG. 1 is configured to reciprocate in the track direction along two guide rails (not shown), but the movable head 104 has a balanced center of gravity with respect to the guide rails. If not, the tracking error signal and the focus error signal may increase at the time of acceleration / deceleration due to the driving of the voice coil motor 113 and the magnet 114, and an off-track or out-of-focus may occur. Therefore, even in such a case, by applying the correction signal to the tracking control loop and the focus control loop in synchronization with the start and stop of the driving of the movable head 104, the tracking error signal and the increase in the focus error signal are offset. can do.

When the focus error signal is corrected as described above, the ultrasonic motor and the voice coil motor are actually driven in advance at the time of assembling and adjusting the apparatus as in the embodiment of FIG. Measure the error signal,
From the result, the correction signal may be stored in the EEPROM. Further, as in the embodiment of FIGS. 7 and 8, a device for measuring the focus error signal is provided in the device, or a device for computing the correction signal is provided, and the correction signal obtained from the measurement result or the computation result is stored in the memory. It is also possible to store it in. When the focus error signal is calculated, the open loop transfer characteristic data of the focus control loop is stored in the EEPROM and the correction signal is calculated from this characteristic data, as in the case where the correction signal of the tracking error signal described above is calculated. Should be calculated. As the calculation method, first, the focus (AF) error displacement is obtained as follows from the open loop transfer characteristic of the focus control loop.

AF error displacement = 1 / (1 + AF open loop transfer function) Next, a step response is obtained from the obtained AF error displacement, and an AF step response that is a correction pattern signal is obtained by differentiating the step response. That is, the correction signal is obtained as follows.

Correction pattern signal = AF speed step response = d / dt (AF error step response) The obtained correction signal is stored in the RAM.

Further, in the embodiment, when the optical head unit and the optical card are relatively moved in the direction orthogonal to the track, the shuttle for mounting the optical card is moved in the direction orthogonal to the track. It is needless to say that the present invention can be applied to prevent the tracking error signal and the focus error signal from increasing at the time of acceleration / deceleration of the optical head unit. Also, when the optical head and the optical card are relatively moved back and forth in the track direction, the optical head is moved,
It is needless to say that the optical card may be moved by an appropriate driving means, and in this case as well, the present invention can be applied to prevent the tracking error signal and the focus error signal from increasing when the optical card is accelerated or decelerated.

[0055]

As described above, according to the present invention, when the light beam and the recording medium relatively move in the track orthogonal direction or the track direction, the correction signal is tracking-controlled in synchronization with the driving start and the driving stop thereof. By applying the voltage to the loop, it is possible to cancel the increase in the tracking error signal generated during acceleration / deceleration, thereby preventing the displacement of the light beam and the tracking error, and stabilizing the operation of the device. Similarly, by applying the correction signal to the focus control loop, it is possible to correct the increase of the focus error signal at the time of acceleration / deceleration, thereby preventing out-of-focus or the like and stabilizing the operation of the apparatus.

[Brief description of drawings]

FIG. 1 is a diagram showing the overall configuration of a first embodiment of an optical information recording / reproducing apparatus according to the present invention.

FIG. 2 is a detailed perspective view of the optical head unit of FIG.

FIG. 3 is a block diagram showing a configuration of a main part of the first embodiment of the present invention.

FIG. 4 is a diagram for explaining the operation of the embodiment of FIG.

FIG. 5 is a block diagram showing a second embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the embodiment of FIG.

FIG. 7 is a block diagram showing a third embodiment of the present invention.

FIG. 8 is a block diagram showing a fourth embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a tracking control system of an optical information recording / reproducing apparatus of a conventional example, a position control system of an objective lens, and a drive system of a shuttle for mounting an optical card.

FIG. 10 is a diagram showing signals of respective parts of the drive system of the shuttle shown in FIG.

FIG. 11 is a diagram for explaining a problem that occurs during acceleration / deceleration of the ultrasonic motor of FIG. 9.

[Explanation of symbols]

 1a, 1b, 1c Photodetector 2, 3 Differential amplifier 5 MPU 8 AT coil 9 Objective lens 14 D / A converter 15 Voltage controlled oscillator (VCO) 17 Ring counter 18 Changeover switch 21 Ultrasonic motor 50 Subtractor 51 D / A converter 52 EEPROM 53 A / D converter 54 RAM 100 Optical card 101 Shuttle 104 Movable head 105 Fixed head 106 Semiconductor laser 113 Voice coil motor

Claims (12)

[Claims] 1. An optical head for irradiating an information recording medium with a light beam, and first driving means for relatively reciprocating the optical head and the recording medium in the information track direction.
Optical information having a tracking control loop for controlling tracking of a light beam of the optical head, and second driving means for relatively moving the optical head and the recording medium in a direction orthogonal to the information track. In the recording / reproducing apparatus, a correction signal generating means for generating a correction signal for correcting the tracking error signal at the time of acceleration / deceleration of the first or second driving means, and the correction signal of the correction signal generating means for the tracking control. A correction signal applying means for applying the correction signal to the loop, and applying the correction signal to the tracking control loop in synchronization with the driving start and the driving stop of the first or second driving means. An optical information recording / reproducing apparatus for correcting a tracking error signal during acceleration / deceleration of the first or second driving means. 2. The optical information recording / reproducing apparatus according to claim 1, wherein the correction signal generating means includes a non-volatile memory that stores a correction signal for correcting a predetermined tracking error signal, An optical information recording / reproducing apparatus, wherein the correction signal stored in the non-volatile memory is transferred to the correction signal applying means when the driving of the first or second driving means is started or stopped. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the correction signal generating means measures a signal level of a tracking error signal during acceleration / deceleration of the first or second driving means. Measuring means and a memory for storing a correction signal obtained from the measurement result of the measuring means, and are stored in the memory when the driving of the first or second driving means is started and stopped. An optical information recording / reproducing apparatus, wherein the corrected signal is transferred to the correction signal applying means. 4. The optical information recording / reproducing apparatus according to claim 3, wherein the measuring unit periodically loads the recording medium when the recording medium is loaded or after the recording medium is loaded. The optical information recording / reproducing apparatus, wherein the signal level of the tracking error signal during acceleration / deceleration of the driving means is measured, and the correction signal of the memory is rewritten based on the measurement result. 5. The optical information recording / reproducing apparatus according to claim 1, wherein the correction signal generating means stores a non-volatile memory for storing open loop transfer characteristic data of the tracking control loop, and the non-volatile memory. And a memory for storing the correction signal obtained by the calculation means, the calculation means for calculating the correction signal of the tracking error signal based on the characteristic data stored in An optical information recording / reproducing apparatus, wherein the correction signal stored in the memory is transferred to the correction signal applying means when the driving means starts driving and when the driving means stops driving. 6. The optical information recording / reproducing apparatus according to claim 1, wherein the correction signal generating means stores a non-volatile memory for storing open loop transfer characteristic data of the tracking control loop, and the non-volatile memory. Calculating means for calculating a correction signal of the tracking error signal based on the characteristic data stored in the first or second
2. The optical information recording / reproducing apparatus, wherein the driving means drives the correction signal in real time when the driving means starts driving and when the driving means stops, and the calculation result is transferred to the correction signal applying means. 7. An optical head for irradiating an information recording medium with a light beam, and first drive means for relatively reciprocating the optical head and the recording medium in the information track direction.
Optical information having a focus control loop for controlling the focus of the light beam of the optical head, and a second driving means for moving the optical head and the recording medium relatively in the direction orthogonal to the information track. In the recording / reproducing apparatus, a correction signal generating means for generating a correction signal for correcting a focus error signal at the time of acceleration / deceleration of the first or second driving means, and the correction signal of the correction signal generating means for the focus control. A correction signal applying unit for applying the correction signal to the focus control loop, the correction signal applying unit applying the correction signal to the focus control loop in synchronization with the start and stop of the driving of the first or second driving unit. An optical information recording / reproducing apparatus which corrects a focus error signal during acceleration or deceleration of the first or second driving means. 8. The optical information recording / reproducing apparatus according to claim 7, wherein the correction signal generating means includes a non-volatile memory that stores a correction signal for correcting a predetermined focus error signal, An optical information recording / reproducing apparatus, wherein the correction signal stored in the non-volatile memory is transferred to the correction signal applying means when the driving of the first or second driving means is started or stopped. 9. The optical information recording / reproducing apparatus according to claim 7, wherein the correction signal generating means measures a signal level of a focus error signal during acceleration / deceleration of the first or second driving means. And a memory for storing a correction signal obtained from the measurement result of the measuring means, at the start of driving of the first or second driving means,
And an optical information recording / reproducing apparatus which transfers the correction signal stored in the memory to the correction signal applying means when the driving is stopped. 10. The optical information recording / reproducing apparatus according to claim 9, wherein the measuring unit periodically loads the recording medium when the recording medium is loaded or after the recording medium is loaded. An optical information recording / reproducing apparatus, which measures a focus error signal during acceleration / deceleration of the driving means and rewrites a correction signal of the memory based on the measurement result. 11. The optical information recording / reproducing apparatus according to claim 7, wherein the correction signal generating means stores a non-volatile memory for storing open loop transfer characteristic data of the focus control loop, and the non-volatile memory. And a memory for storing the correction signal obtained by the calculation means, the calculation means for calculating the correction signal of the focus error signal based on the characteristic data stored in An optical information recording / reproducing apparatus, wherein the correction signal stored in the memory is transferred to the correction signal applying means when the driving means starts driving and when the driving means stops driving. 12. The optical information recording / reproducing apparatus according to claim 7, wherein the correction signal generating means stores a non-volatile memory for storing open loop transfer characteristic data of the focus control loop, and the non-volatile memory. Calculating means for calculating a correction signal of the focus error signal based on the characteristic data stored in the first and second driving means and when the driving means stops the driving in real time. An optical information recording / reproducing apparatus, characterized in that a correction signal is calculated by the method and the calculation result is transferred to the correction signal applying means.