JP2003168268A - Optical pickup feeder - Google Patents

Abstract

(57) [Problem] To provide an optical pickup feeding device capable of accurately and quickly positioning an optical pickup and achieving low noise and low power consumption. An optical disc having a traverse mechanism for moving an optical pickup in a radial direction of a recording medium while controlling a relative position between the optical pickup and the recording medium so that information can be recorded or reproduced on the recording medium. An optical pickup feeder in an apparatus, comprising: a position detecting means for detecting position information of an optical pickup; and a drive waveform switching means for switching a drive current waveform of a stepping motor for driving a traverse mechanism, wherein the position is detected by the position detecting means. The drive current switching means switches the drive current waveform according to the position of the optical pickup.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup feeding device for moving an optical pickup in an optical disc recording / reproducing apparatus for recording / reproducing an optical disc.

[0002]

2. Description of the Related Art In an optical disk recording / reproducing apparatus, in order to record an information signal on a predetermined track on a disk or reproduce an information signal recorded on the track, an optical pickup is moved onto a target track. It is necessary to irradiate a target track with laser light. For that purpose, the optical pickup has to be positioned on a target track, and there is a seek (servo) system as a servo system for moving the optical pickup to a target position in the radial direction of the optical disk in order to perform such positioning.

The seek servo system is composed of a sled (coarse movement) motor system and an actuator system in the optical pickup. The sled motor system is a system in which, for example, a stepping motor roughly seeks an optical pickup to detect a position with an encoder for positioning. The actuator system finely seeks the optical pickup by a biaxial actuator, for example.

The operation sequence of such a seek servo system will be described below. First, the seek operation is roughly performed near the target track position. Even if the optical pickup stops near the address indicating the target track,
The movable part of the actuator in the optical pickup does not stop immediately, but stops with a predetermined settling time while vibrating.

Next, a track pull-in operation is performed to read the arrived address information. Here, if a track pull-in operation is executed at a time when the track eccentric speed is large, a pull-in error is likely to occur. Therefore, the track pull-in operation is waited until the eccentric speed approaches zero.

Then, the laser beam tracks the track,
When tracking is performed, the address is read and a difference from the target address is detected, fine seek is executed by the difference. Even at this time, if the eccentric speed is high, it is difficult to perform stable seek control.Therefore, the system waits until the eccentric speed becomes small, and the target track address is reached after the eccentric speed becomes sufficiently small and Alternatively, the reproduction operation is executed.

The following are prior arts relating to a drive circuit of a stepping motor which performs such a seek operation.

First, in Japanese Utility Model Publication No. 1-153030, a stepping motor drive signal is a sine wave.
There is disclosed a head feeding device that enables accurate and precise head feeding by driving a stepping motor by stepping with a signal obtained by finely dividing the sine wave into a plurality of steps.

In Japanese Utility Model Application Laid-Open No. 2-128211, the drive control circuit sets the drive current at the stable point of the stepping motor to 0 (based on the position error information by the detecting means for detecting the position error information of the optical pickup). (0) to form a tilted trapezoidal wave drive pulse, and drive the stepping motor by the drive pulse to move the optical pickup, thereby reducing the power consumption of the optical pickup feeding device and smoothing the optical pickup. Also disclosed is an optical pickup moving device that can be sent quietly.

Further, Japanese Patent Laid-Open No. 9-63069 discloses an optical pickup device in which a system controller calculates the number of tracks to a target position for positioning the optical pickup, and the control method of the optical pickup is changed according to the number of tracks. Has been done. That is, when the number of tracks is larger than the predetermined number, the system controller calculates the number of steps, and based on the number of steps, the stepping motor is driven in the steady high-speed feed excitation mode to move the optical pickup at high speed. On the other hand, when the number of tracks is smaller than the predetermined number, the stepping motor is micro-step-driven in the high-speed trace excitation mode based on the number of steps to move the optical pickup at a speed slower than the steady high-speed moving speed. As a result, the range of the track jump can be widened and the optical pickup can be quickly positioned at the track center.

[0011]

As described above, in the conventional drive circuit for the stepping motor which performs the seek operation, the suspension holding the lens inside the optical pickup is used to realize high-speed access with an inexpensive structure. We have already adopted the method of driving the stepping motor in micro steps so as not to shake. Therefore, when performing the seek operation, first, the optical pickup is fed at high speed by the high-speed feed exciting means over a long distance,
The microstep excitation means performs microstep feed so as not to shake the optical pickup.

However, in order to stop the optical pickup at a predetermined position more accurately and at high speed, it is necessary to measure the radial position of the recording medium during the seek operation. That is, the optical pickup needs to read the position information of the recording medium previously recorded on the recording medium during high-speed feeding.

Then, in order to perform high-speed feeding, the stepping motor is generally driven by two-phase excitation. As a result, the vibration of the suspension holding the lens inside the optical pickup becomes large, the lens is likely to vibrate, and there is a possibility that the position information of the recording medium cannot be read.

Further, when the optical pickup is moved by the high-speed feed excitation means, the noise generated is larger than that in the microstep drive. Therefore, when the optical disk recording / reproducing device equipped with such an optical pickup feeding device is applied to a portable AV device, for example, a camera-integrated recording device, the drive sound during seek operation may be recorded by the microphone. There was a problem that there was.

Further, as a measure against the driving sound during the seek operation,
If the seek operation is performed by the micro-step excitation means, the electric power supplied to the stepping motor is reduced, and the load margin is reduced. Or it becomes impossible to transfer the optical pickup,
Furthermore, there is a problem in that it is necessary to increase the applied voltage supplied to the stepping motor, which increases power consumption.

Further, in order to solve the problem,
It is more preferable to use a motor with a large generated torque as the stepping motor, but in general, in order to obtain a larger generated torque, the volume of the motor tends to be large, and there is also a problem that the entire device becomes large. there were.

In order to solve the above-mentioned problems, the present invention provides an optical pickup feeding device which can position an optical pickup accurately and at high speed, and can achieve low noise and low power consumption. The purpose is to provide.

[0018]

In order to achieve the above object, an optical pickup feeding device according to the present invention includes an optical pickup and a recording medium so that information can be recorded on or reproduced from the recording medium. An optical pickup feeding device in an optical disk device having a traverse mechanism for moving an optical pickup in a radial direction of a recording medium while controlling a relative position, the position detecting means for detecting position information of the optical pickup, and the traverse mechanism. Drive waveform switching means for switching the drive current waveform of the stepping motor, wherein the drive current waveform is switched by the drive waveform switching means according to the position of the optical pickup detected by the position detecting means.

With this configuration, the optical pickup can be positioned at high speed, and the power consumption of the stepping motor can be reduced during the seek operation.

Further, in the optical pickup feeding device according to the present invention, it is preferable that the drive current waveform is a current waveform having different duty ratios, or a substantially square wave shape and a substantially trapezoidal wave shape.

Further, in the optical pickup feeding device according to the present invention, the same effect can be expected even if the drive waveform switching means switches the drive system instead of the drive current waveform. Two-phase driving and micro-step driving are preferable as the switching driving method.

In order to achieve the above object, the optical pickup feeding device according to the present invention sets the relative position of the optical pickup and the recording medium so that information can be recorded or reproduced on the recording medium. An optical pickup feeding device in an optical disc device having a traverse mechanism for moving an optical pickup in a radial direction of a recording medium while controlling, wherein a moving speed of the traverse mechanism is changed according to an operation mode of the optical disc device. To do.

With this configuration, it is possible to reduce the seek operation sound captured by the microphone during recording, and it is possible to reduce noise.

In order to achieve the above object, the optical pickup feeding device according to the present invention controls the relative position of the optical pickup and the recording medium so that information can be recorded or reproduced on the recording medium. While being an optical pickup feeding device in an optical disc device having a traverse mechanism for moving an optical pickup in the radial direction of a recording medium, a drive waveform switching means for switching a drive current waveform of a stepping motor for driving the traverse mechanism is provided. The drive current waveform is switched by the drive waveform switching means according to the operation mode of the device.

With this configuration, the driving sound taken in by the microphone during the seek operation can be reduced, the positioning accuracy of the optical pickup can be improved, and high-speed access and low power consumption during reproduction can be realized. It becomes possible.

Further, in the optical pickup feeding device according to the present invention, it is preferable that the drive current waveform has a substantially square wave shape or a substantially trapezoidal wave shape.

Further, in the optical pickup feeding device according to the present invention, the same effect can be expected by switching the driving method instead of the driving current waveform in the driving waveform switching means. Two-phase driving and microstep driving are preferable as the switching driving method.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An optical pickup feeding device according to a first embodiment of the present invention will be described below with reference to the drawings. 1 is a configuration diagram of an optical pickup feeding device according to a first embodiment of the present invention.

As shown in FIG. 1, an optical pickup 2 for reading information from an optical disc 1 which is a recording medium for optically recording information has a laser diode 3 for outputting a laser beam for reading information, and an optical disc 1. The objective lens 4 for irradiating the laser light output from the laser diode 3 to the optical disk 1, the photodetector 6 to which the reflected light of the laser light from the optical disk 1 is guided through the beam splitter 5, and the laser light for reading information on the optical disk 1. The objective lens 4 to irradiate is in the optical axis direction (focusing direction)
And a biaxial actuator 7 for moving the optical disc 1 in the radial direction (tracking direction).

FIG. 2 is a diagram showing a moving state of the optical pickup 2 in the optical pickup feeding device according to the first embodiment of the present invention. As shown in FIGS. 2 (a) and 2 (b), the optical pickup 2 is provided with a connector 9a for transmitting / receiving an electric signal and for allowing the optical pickup 2 to move in the disc radial direction. And is electrically connected to the substrate 9 by the wiring substrate 8 made of an elastic member.

The optical pickup 2 having such a configuration supplies the tracking detection signal detected by the photodetector 6 to the differential amplifier 10 of the tracking servo system, and the tracking error obtained by the differential amplifier 10 via the tracking servo circuit 11. The signal will be fed back to the biaxial actuator 7. By doing so, the tracking servo can be applied so as to accurately trace the track on the optical disc 1.

Similarly, the focus detection signal detected by the photodetector 6 is also supplied to the differential amplifier 12 of the focus servo system, and the focus servo circuit 13 is supplied.
The focus error signal obtained by the differential amplifier 12 is fed back to the biaxial actuator 7 via. By doing so, focus servo is applied so that the objective lens 4 is focused on the recording surface on the optical disc 1.

Further, the optical pickup 2 is screwed onto a feed screw shaft 21 which is rotationally driven by a stepping motor 20, and can reciprocate in the radial direction of the optical disc along a guide shaft (not shown).

Further, the optical pickup 2 obtains the position information already recorded on the optical disc 1 by the position detecting means 14 based on the signal from the photodetector 6, and as a result, the optical pickup 2 moves in the radial direction of the optical disc 1. It is possible to determine which position of the.

A drive stage 15 composed of a power transistor or the like for applying a voltage to the stepping motor 20 is connected to a terminal portion (not shown) of the stepping motor 20. Further, the drive stage 15 has a control unit 16 which determines the rotation speed and drive waveform of the stepping motor 20 based on the signal from the position detection means 14.
And a drive waveform switching means 17 for switching the drive current waveform of the stepping motor 20 are connected.

Here, FIG. 4 is a structural example of the drive stage 15 in the optical pickup feeding device according to the first embodiment of the present invention. As shown in FIG. 4, a digital signal processing circuit 38 for supplying a control signal to the stepping motor 20, LPFs 39 and 40 for converting the control signal from the digital signal processing circuit 38 into a linear signal, and an LP
It is composed of a drive unit 50 for amplifying the power level of the linear control signal from F39 and F40.

Further, the digital signal processing circuit 38 outputs the command signal for the operation to the stepping motor 20 and, depending on the command signal from the control unit 16, the number of command steps is for A phase or B phase. Drive voltage switching means 17 for outputting a voltage value for use with the waveforms and waveform output devices 22 and 23 for converting the A-phase or B-phase voltage from the drive waveform switching means 17.

Here, all or a part of the digital signal processing circuit 38 is composed of a DSP (digital signal processor). Further, the control unit 16 and the drive waveform switching unit 17 may be configured by software.

Further, inside the drive waveform switching means 17,
A memory (not shown) capable of storing predetermined information is incorporated.

The control section 16 and the drive waveform switching means 1
7 has a waveform correction means for correcting the drive current waveform for driving the motor so that the drive distance by the rotation of the motor for each step is linearly controlled. LPF3
9 is the LPF 40 from the resistor 24 and the capacitor 26.
Is composed of a resistor 25 and a capacitor 27, respectively.

Further, the driving section 50 includes an amplifier 28 for amplifying the power level of the linear control signal, and a level shift circuit 30 for shifting the center of the amplitude of the amplified linear control signal to the midpoint potential. Reference numeral 34 amplifies a control signal output from one output terminal of the level shift circuit 30 and supplies it to one end of the A phase coil of the stepping motor 20 as an A phase stepping motor drive current. The control signal output from the other output terminal of 30 is inverted and amplified, and is supplied to the other end of the A-phase coil of the stepping motor 20 as the A-phase inversion stepping motor drive current.

Similarly, an amplifier 29 for amplifying the power level of the linear control signal and a level shift circuit 31 for shifting the center of the amplitude of the amplified linear control signal to the midpoint potential are also provided, and the amplifier 36 has a level. The control signal output from one output terminal of the shift circuit 31 is amplified and supplied to one end of the B-phase coil of the stepping motor 20 as a B-phase stepping motor drive current, and the inverter 33 controls the other of the level shift circuit 31. The control signal output from the output terminal is inverted and amplified, and is supplied to the other end of the B-phase coil of the stepping motor 20 as a B-phase inversion stepping motor drive current.

With the above configuration, the control unit 16 calculates the number of pulses of the stepping motor 20 required for the optical pickup 2 to move to a predetermined position in response to the seek command. Further, the control unit 16 controls the constant feed speed at which the optical pickup 2 designated beforehand is movable,
The seek profile required for movement is calculated based on the acceleration until reaching the steady speed, the acceleration at deceleration from the steady speed to the stationary state, and the like. Figure 3
FIG. 3 is an exemplary diagram of a seek profile in the optical pickup feeding device according to the first embodiment of the present invention, and such a seek profile is calculated for each seek command.

The control unit 16 creates a signal necessary for driving the stepping motor 20 according to the calculated seek profile, and the driving stage 15 drives the stepping motor 20.
Is powered.

FIG. 7 is a diagram showing an example of a drive waveform of a specific phase in the optical pickup feeding device according to the second aspect.

The operation of the optical pickup feeding device according to the first embodiment will be described below. Waveform output device 22
And 23 are configured to be capable of PWM (pulse width modulation) driving, and are stored in a memory arranged inside the drive waveform switching means 17 according to a command from the control unit 16 as shown in FIG. The drive waveform and the drive waveform as shown in FIG. 6 are switched.

Here, FIG. 5 is an exemplary diagram of a drive waveform at a duty ratio of 100%, and FIG. 6 is an exemplary diagram of a drive waveform at a duty ratio of 100% or less (in the present embodiment, a duty ratio of 70%). Is.

For example, FIG. 7 shows an optical pickup feeding device which can feed the optical pickup 2 at a duty ratio of 100% with a voltage applied to the stepping motor 20 of 5 V, an acceleration start speed of 300 pps, a steady feed speed of 1700 pps. So at the start of acceleration
Duty ratio of 1 pulse and 3 pulses at the end of deceleration
It has been confirmed that the optical pickup 2 can be moved even when the duty ratio is set to 00% and the remaining pulse is set to 70%.

In this way, about 25% of the power consumption can be reduced by driving a part of the pulses during acceleration and deceleration with a duty ratio of 100% and the remaining pulses with a duty ratio of 70%. It will be possible.

This is because the electric power is required to move the optical pickup 2 at the start of acceleration, but once it starts moving, it can move even if the supplied electric power is small due to inertia or the like. On the contrary, at the time of deceleration, it is necessary to drive at a duty ratio of 100% for the last few pulses because it is necessary to decelerate so as to overcome such inertia.

When the optical pickup 2 moves in the X direction as shown in FIG. 2 (a), the wiring board 8 is deformed as shown in FIG. 2 (b). As a result, due to the elasticity of the wiring board 8, a load is generated in the direction opposite to the moving direction X.

Therefore, since the position of the optical pickup 2 in the radial direction can be known by the position detecting means 14, the reaction force due to the bending elasticity of the wiring board 8 can be overcome, so that the wiring board 8 can be overcome.
By increasing the duty ratio of the drive waveform from the position where the bending elasticity of
You can increase the force to move in the direction. By doing so, it is possible to reduce the influence of the bending elasticity of the wiring board 8.

As described above, according to the first embodiment,
Low power consumption can be realized by changing the pulse width during the seek operation. Furthermore, by changing the pulse width depending on the position of the optical pickup, it is possible to correct the reaction force due to the elasticity of the wiring board 8, and it is possible to reliably secure the movement amount required for the optical pickup 2.

In the first embodiment, only the pulse width of the applied current is changed, but the same effect can be expected by changing the applied voltage.

Further, in the first embodiment, the elastic force of the wiring board is corrected. However, depending on the optical disk recording / reproducing apparatus, whether the optical pickup is at the inner peripheral position or the outer peripheral position is determined. Some are configured to detect by a push-type switch. Therefore, the position at which the drive waveform is switched is not limited to that in the first embodiment, and the drive waveform may be switched from the position where the pressing of the switch is started.

(Second Embodiment) An optical pickup feeding device according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 8 shows the second embodiment of the present invention.
FIG. 6 is an exemplary diagram of a trapezoidal wave drive waveform in the optical pickup feeding device according to the first embodiment.

Here, the optical pickup feeding device according to the second embodiment differs from the optical pickup feeding device according to the first embodiment in that the drive waveform switching means 17 is used.
The waveforms to be switched by are the substantially square wave shape as shown in FIG. 5 and the substantially trapezoidal wave shape as shown in FIG. That is, the drive waveform switching means 17 sets the several pulses at the start of acceleration and the last few pulses at the end of deceleration into drive waveforms of a substantially square wave shape, and the remaining pulses into a drive waveform of a trapezoidal wave shape. .

For example, FIG. 9 shows an example of a drive waveform of a specific phase in the optical pickup feeding device according to the second embodiment of the present invention. As shown in FIG. 9, the voltage applied to the stepping motor 20 is 5V, acceleration starts at 300
pps, steady feed is 1700 pps, and in an optical pickup feed device capable of transferring the optical pickup 2 with a square-wave drive waveform, the drive waveforms of the first three pulses at the start of acceleration and the last three pulses at the end of deceleration are square. It has been confirmed that the optical pickup 2 can be transferred even in the case of a wavy shape and the driving waveform of the remaining pulse has a sine wave shape.

As described above, by driving the driving waveform in a part of the section during acceleration / deceleration in the seek operation in a square wave shape and driving waveforms in the remaining steps in a trapezoidal shape, the first embodiment is provided. In addition to the effect of the optical pickup feeding device, the power consumption at the time of seek can be reduced by the difference of the waveform area, and when the optical pickup 2 is transferred, the drive waveform in most of the section is made into a trapezoidal wave, so that stepping It is possible to reduce the rotation noise of the motor 20.

Further, since the change in the torque generated when the stepping motor 20 rotates can be made smooth as compared with the square wave shape, it is possible to reduce the driving sound generated from the screwed portion. .

As described above, according to the second embodiment,
Low power consumption can be realized by changing the drive waveform to a substantially trapezoidal wave. Further, the gradual switching of the current reduces the vibration generated from the screwing portion when the optical pickup 2 moves. That is, low noise can be realized and the biaxial actuator 7
It is also possible to suppress the vibration of the objective lens 4 elastically supported by.

Here, FIG. 10 is a diagram showing the measurement results of the generated acceleration applied to the biaxial actuator 7 when the stepping motor 20 is driven by a square wave during the seek operation,
FIG. 11 shows the stepping motor 2 during the seek operation.
FIG. 10 is a diagram showing a measurement result of generated acceleration applied to the biaxial actuator 7 when 0 is driven with a drive waveform as shown in FIG. 9.

As is clear from FIGS. 10 and 11,
Compared to the case of driving only with a square wave as shown in FIG. 10,
As shown in FIG. 11, when the trapezoidal wave drive is incorporated during the seek operation, the generated acceleration applied to the biaxial actuator 7 is smaller and the vibration is smaller. Therefore,
The focus servo circuit 13 can perform focus servo during the seek operation. As a result, the position detection unit 14 can acquire the position information already recorded on the optical disc 1 in real time even during the seek operation, and the position information and the drive pulse number are collated to provide feedback. As a result, the accuracy of the stop position of the optical pickup 2 can be improved.

In the second embodiment, the current waveform is described as a substantially trapezoidal waveform using a waveform as shown in FIG. 8. However, the substantially trapezoidal wave has a sine wave shape as shown in FIG. May be In that case, the switching state of the drive waveform at the time of startup is as shown in FIG. Also,
As shown in FIG. 14, it can be understood that it is preferable to drive in a sinusoidal shape from the viewpoint of noise reduction and improvement of stop position accuracy, but since it may be possible to drive depending on load conditions, It suffices to select the current waveform to be switched depending on the load condition.

(Third Embodiment) An optical pickup feeding device according to a third embodiment of the present invention will be described below with reference to the drawings. FIG. 15 is a block configuration diagram of an optical pickup feeding device according to the third embodiment of the present invention, and FIG. 16 is a configuration diagram of a drive stage 15 in the optical pickup feeding device according to the third embodiment of the present invention. .

The optical pickup feeding device according to the third embodiment differs from the optical pickup feeding devices according to the first and second embodiments in that the waveform switched by the drive system switching means 17 is as shown in FIG. This is the point where there are two-phase drive waveforms and microstep drive waveforms as shown in FIG.

As described above, the drive waveform switching means 17 capable of switching the drive method between two different methods causes the remaining several pulses at the beginning of acceleration and the last few pulses at the end of deceleration to be two-phase driven and the remaining pulses. The pulse will be switched to be driven by microstep driving.
FIG. 18 is a view showing an example of drive waveform switching at the time of starting the optical pickup feeding device according to the third embodiment.

For example, the voltage applied to the stepping motor 20 is 5 V, the acceleration start is 300 pps, and the steady feed 17
In the optical pickup feeding device capable of transferring the optical pickup 2 with a square wave drive waveform,
As shown in FIG. 18, even when the driving method of the first three pulses at the start of acceleration and the last three pulses at the end of deceleration is two-phase driving and the driving method of the remaining pulses is microstep driving, It has been confirmed that the optical pickup 2 can be transported.

As described above, the driving method in a part of the section during acceleration / deceleration in the seek operation is the two-phase driving, and the driving method in the remaining steps is the micro-step driving, so that only the difference in the area of the waveform is consumed. Electric power can be reduced.

Further, when the optical pickup 2 is transferred, the driving method of most of the sections is set to the micro step drive, so that the rotation noise of the stepping motor 20 is reduced and the torque generated when the stepping motor 20 rotates. Since the change can be made smoother than that in the case of driving by two-phase driving, the driving sound generated from the screwing portion can be reduced.

Further, FIG. 19 shows that when the stepping motor 20 is micro-step driven during the seek operation,
It is a figure which shows the result of having measured the generated acceleration applied to the biaxial actuator 7.

As is clear from FIGS. 10 and 19,
Compared to the case of driving only with a square wave as shown in FIG. 10, the case where the micro step drive is incorporated during the seek operation as shown in FIG.
It can be seen that there is little vibration applied to.

As described above, according to the third embodiment,
Low power consumption can be realized by using two-phase driving and microstep driving together as a driving method and driving most of the seek operation by microstep driving. Further, the gradual switching of the current reduces the vibration generated from the screwing portion when the optical pickup 2 moves. That is, noise reduction can be realized, and vibration of the objective lens 4 elastically supported by the biaxial actuator 7 can be suppressed,
The focus servo circuit 13 can perform focus servo during the seek operation.

As a result, the position detecting means 14 can obtain the position information already recorded on the optical disk 1 in real time even during the seek operation, and by comparing the position information with the number of drive pulses. By applying the feedback, the accuracy of the stop position of the optical pickup 2 can be improved.

(Fourth Embodiment) Next, an optical pickup feeding device according to a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 20 shows the fourth embodiment of the present invention.
FIG. 21 is a block configuration diagram of an optical pickup feeding device according to the present invention, and FIG. 21 is a configuration diagram of a drive stage according to a fourth embodiment of the present invention.

The optical pickup feeding device according to the fourth embodiment differs from the optical pickup feeding device according to the first embodiment in that the drive current waveform switching means 17 does not exist as shown in FIGS. It is in.

The operation procedure of the optical pickup feeding device according to the fourth embodiment is as follows. The control unit 16 gives a command to change the seek speed according to the operation mode of the device. Here, the operation mode of the device means a mode for recording information, a mode for reproducing information, and the like. For example, in the recording mode, the seek speed is slowed down, or in the reproduction mode, the seek speed is reduced. The control unit 16 gives a command to increase the speed.

Specifically, for example, when the operation mode is the recording mode, a seek command is issued so that the seek speed becomes 40 mm / sec, and when the operation mode is the reproducing mode,
It is assumed that the seek command is issued so that the seek speed becomes 48 mm / sec. The difference in the driving sound generated during the seek operation due to the difference in seek speed at this time is 48
40 mm / more than the driving sound when driven at mm / sec
It has been confirmed that the driving sound when driven in sec is lower by 2 to 3 dBA.

As described above, according to the fourth embodiment,
By changing the seek speed depending on the operation mode, it is possible to reduce the drive sound during the seek operation during recording. As a result, it is possible to prevent or reduce the sound generated during the seek operation during recording from jumping into the recording microphone.

Here, FIG. 22 shows a seek speed of 40 mm / s.
FIG. 23 is a diagram showing the measurement result of the generated acceleration applied to the biaxial actuator 7 in the case of ec.
It is a figure which shows the measurement result of the generated acceleration applied to the biaxial actuator 7 in the case of mm / sec.

From the results shown in FIGS. 22 and 23, it can be confirmed that the vibration applied to the biaxial actuator 7 is smaller in FIG. 22 where the seek speed is slower. Therefore, it is possible to apply the focus servo by the focus servo circuit 13 during the seek operation.

As a result, the position detecting means 14 can obtain the position information already recorded on the optical disc 1 in real time even during the seek operation, and the position information and the driving pulse number are collated and fed back. By applying, it is possible to improve the accuracy of the stop position of the optical pickup 2.

By doing so, it is possible to accurately reach the recordable disc area during recording, so that it is possible to reduce recording mistakes and a buffer provided in the apparatus for reducing recording mistakes. Since the capacity of the memory (not shown) can be reduced, the device itself can be constructed at low cost.

(Fifth Embodiment) An optical pickup feeding device according to a fifth embodiment of the present invention will be described below with reference to the drawings. The block configuration of the optical pickup feeding device according to the fifth embodiment and the configuration of the drive stage 15 are the same as those in FIGS. 1 and 4 shown in the first embodiment, and therefore a detailed description thereof will be omitted.

FIG. 24 is a diagram comparing drive waveforms during recording and reproduction when a trapezoidal waveform is used when the operation mode of the optical pickup device is in the recording mode, and FIG. FIG. 27 is a diagram comparing drive waveforms at the time of recording and reproduction when a sine waveform is used in a certain case, and FIG. 26 is also at the time of recording and reproduction when microstep drive is used in the same recording mode. It is the figure which compared the drive waveform. In FIGS. 24 to 26, the solid line part indicates the reproduction time, and the broken line part indicates the recording time.

The optical pickup feeding device according to the fifth embodiment differs from the optical pickup feeding device according to the first embodiment in that the timing at which the waveform is switched by the drive current waveform switching means 17 shown in FIGS. 1 and 4. Is a point that depends on the operation mode.

In the optical pickup feeding device according to the fifth embodiment, the control unit 16 gives a command to switch the drive waveform according to the operation mode of the optical pickup device. That is, when the operation mode of the optical pickup device is the recording mode, the drive waveform is instructed to be driven by a trapezoidal wave or a sine wave, or in the reproduction mode, the drive waveform is driven by a square wave. Will be given.

It has been confirmed that the driving sound generated during the seek operation can be reduced by 2 to 3 dBA by driving with the trapezoidal wave as described above as compared with the case of driving with the square wave. On the other hand, when driving with a sine wave, it has been confirmed that it can be lowered by 3 to 4 dBA. This is also clear by comparing FIGS. 24 to 26.

As described above, according to the fifth embodiment,
By changing the drive voltage waveform applied to the stepping motor according to the operation mode of the optical pickup device, it is possible to reduce the drive sound during the seek operation during recording. As a result, it is possible to prevent or reduce the sound generated during the seek operation during recording from jumping into the recording microphone.

Further, as shown in FIGS. 10, 11 and 14, it has been confirmed that the slower the seek speed is, the less vibration is applied to the biaxial actuator 7. Therefore, it is possible to apply the focus servo by the focus servo circuit 13 during the seek operation.

As a result, the position detecting means 14 can obtain the position information already recorded on the optical disc 1 in real time even during the seek operation, and the position information and the driving pulse number are collated and fed back. By applying, it is possible to improve the accuracy of the stop position of the optical pickup 2.

By doing so, at the time of recording,
Since the recordable disc area can be accurately reached, the recording error can be reduced, and the capacity of the buffer memory (not shown) provided in the device to reduce the recording error can be reduced. Therefore, the device can be constructed at low cost.

In this embodiment, when driving with a sine wave and a trapezoidal wave, the driving voltage is higher than when driving with a square wave. When it is difficult to drive, the drive voltage may be lowered. In that case, since the drive load margin decreases, the drive frequency may be slower than that of the square wave.

Further, in the present embodiment, the driving waveform is switched, but two driving methods of two-phase driving and microstep driving may be switched, and the same applies in this case. You can expect to get the effect of.

[0095]

As described above, according to the optical pickup feeding device of the present invention, the power consumption can be reduced by switching the drive waveform or the drive system according to the situation.

Further, since the switching of the current becomes gentle, it is possible to reduce the vibration generated from the screwing portion when the optical pickup moves, and it is possible to reduce the noise.

Further, since the vibration of the objective lens elastically supported by the biaxial actuator can be suppressed, the focus servo can be applied during the seek operation, and the position information already recorded on the optical disk can be searched. It can be acquired in real time even during operation, and the accuracy of the stop position of the optical pickup can be improved by applying feedback by comparing the position information with the number of drive pulses.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an optical pickup feeding device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a moving state of the optical pickup in the optical pickup feeding device according to the first embodiment of the present invention.

FIG. 3 is an exemplary diagram of a seek profile.

FIG. 4 is a configuration diagram of a drive stage in the optical pickup feeding device according to the first embodiment of the present invention.

FIG. 5 is an exemplary diagram of a drive waveform at a duty ratio of 100%.

FIG. 6 is a view showing an example of drive waveforms at a duty ratio of 70%.

FIG. 7 is an exemplary diagram of a drive waveform of a specific phase in the optical pickup feeding device according to the first embodiment of the present invention.

FIG. 8 is an exemplary diagram of a trapezoidal wave drive waveform.

FIG. 9 is an exemplary diagram of a drive waveform of a specific phase in the optical pickup feeding device according to the second embodiment of the present invention.

FIG. 10 is a diagram showing measurement results of generated acceleration applied to a biaxial actuator.

FIG. 11 is a diagram showing measurement results of generated acceleration applied to a biaxial actuator.

FIG. 12 is a view showing an example of a sine wave drive waveform.

FIG. 13 is an exemplary diagram of drive waveforms of a specific phase in the optical pickup feeding device according to the second embodiment of the present invention.

FIG. 14 is a diagram showing measurement results of acceleration generated on a biaxial actuator.

FIG. 15 is a block configuration diagram of an optical pickup feeding device according to a third embodiment of the present invention.

FIG. 16 is a configuration diagram of a drive stage in an optical pickup feeding device according to a third embodiment of the present invention.

FIG. 17 is a view showing an example of a microstep drive waveform.

FIG. 18 is an exemplary diagram of drive waveform switching at startup of the optical pickup feeding device according to the third embodiment of the present invention.

FIG. 19 is a diagram showing measurement results of generated acceleration applied to a biaxial actuator.

FIG. 20 is a block configuration diagram of an optical pickup feeding device according to a fourth embodiment of the present invention.

FIG. 21 is a configuration diagram of a drive stage in an optical pickup feeding device according to a fourth embodiment of the present invention.

FIG. 22 is a diagram showing measurement results of generated acceleration applied to a biaxial actuator.

FIG. 23 is a diagram showing measurement results of generated acceleration applied to a biaxial actuator.

FIG. 24 is a drive waveform comparison diagram during recording and reproduction.

FIG. 25 is a drive waveform comparison diagram during recording and reproduction.

FIG. 26 is a drive waveform comparison diagram during recording and reproduction.

[Explanation of symbols]

1 optical disc 2 optical pickup 3 Laser diode 4 Objective lens 5 Beam splitter 6 Photo detector 7 2-axis actuator 8 wiring board 9 substrates 10, 12 Differential amplifier 11 Tracking servo circuit 13 Focus servo circuit 14 Position detection means 15 drive stages 16 Control unit 17, 42 Drive waveform switching means 20 stepping motor 21 Feed screw shaft 22, 23 Waveform output device 24, 25 resistors 26, 27 capacitors 28, 29, 34, 36 amplifiers 30, 31 Level shift circuit 32 inverter 38 Digital signal processing circuit 39, 40 LPF 50 Drive

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02P 8/12 H02P 8/00 B 8/22 H C (72) Inventor Eiji Ueda Kadoma City, Osaka Prefecture Kadoma Address 1006 Matsushita Electric Industrial Co., Ltd. F-term (reference) 5D088 NN03 NN15 NN17 NN26 PP02 SS03 SS14 TT04 UU07 5D117 AA02 CC06 EE08 EE13 FF25 FF28 JJ06 JJ10 5H580 AA02 BB01 BB02 BB05 CB04 FA04 H08FA14 FA14 FA14 FA14 FA14 FA14 FA14 FA14 FA14 FA14 FA14 FA14 FA14 FA14 FA01

Claims (10)

[Claims] 1. A traverse for moving the optical pickup in a radial direction of the recording medium while controlling a relative position between the optical pickup and the recording medium so that information can be recorded or reproduced on the recording medium. An optical pickup feeding device in an optical disc device having a mechanism, comprising position detecting means for detecting position information of the optical pickup, and drive waveform switching means for switching a drive current waveform of a stepping motor for driving the traverse mechanism, An optical pickup feeding device characterized in that the drive current waveform is switched by the drive waveform switching means in accordance with the position of the optical pickup detected by the position detection means. 2. The optical pickup feeding device according to claim 1, wherein the drive current waveform is a current waveform having a different duty ratio. 3. The optical pickup feeding device according to claim 1, wherein the drive current waveform has a substantially square wave shape and a substantially trapezoidal wave shape. 4. The optical pickup feeding device according to claim 1, wherein the drive waveform switching means switches the drive system instead of the drive current waveform. 5. The optical pickup feeding device according to claim 4, wherein the driving method is two-phase driving and microstep driving. 6. A traverse for moving the optical pickup in a radial direction of the recording medium while controlling a relative position between the optical pickup and the recording medium so that information can be recorded or reproduced on the recording medium. An optical pickup feeding device in an optical disc device having a mechanism, wherein the moving speed of the traverse mechanism is changed according to an operation mode of the optical disc device. 7. A traverse for moving the optical pickup in a radial direction of the recording medium while controlling a relative position between the optical pickup and the recording medium so that information can be recorded or reproduced on the recording medium. An optical pickup feeding device in an optical disc device having a mechanism, comprising: a drive waveform switching means for switching a drive current waveform of a stepping motor for driving the traverse mechanism, the drive waveform switching device according to an operation mode of the optical disc device. An optical pickup feeding device, characterized in that the driving current waveform is switched by means. 8. The optical pickup feeding device according to claim 7, wherein the drive current waveform has a substantially square wave shape and a substantially trapezoidal wave shape. 9. The optical pickup feeding device according to claim 7, wherein the drive waveform switching means switches the drive system instead of the drive current waveform. 10. The optical pickup feeding device according to claim 9, wherein the driving method is two-phase driving and microstep driving.