JP6010335B2 - Drive control system - Google Patents

Description

  The present invention relates to a drive control system for driving an actuator structure that moves a minute distance.

As is well known, a known image sensor such as a CCD or CMOS mounted on a video camera, an electronic still camera, or the like is configured by arranging a large number of minute optical sensors vertically and horizontally. Each optical sensor outputs a signal corresponding to the intensity of light at a minute point.
Although the resolution (resolution) of the image pickup device has been improved by technical innovation in the technical field, there is a limit to increasing the degree of integration of the photosensors, that is, to make the distance between adjacent photosensors short. Therefore, in order to increase the resolution by artificially reducing the distance between the optical sensors, a method of moving the image sensor by a minute distance in the vertical direction and the horizontal direction is employed. Hereinafter, this technique is referred to as “pixel shifting” in the present specification.
Patent document 1 discloses the technical content regarding pixel shifting by the same applicant and the same inventor.

Japanese Patent No. 3907560

As disclosed in Patent Document 1, pixel shifting is performed by fixing an image pickup element to an actuator structure that can move a minute distance, and applying a voltage to a piezoelectric element incorporated in the actuator structure for only a minute distance. Realized by driving.
Since the image sensor is driven at a minute distance in order to improve the resolution, it is desirable that the time required for the movement of the minute distance of the image sensor is shorter. In particular, when the subject moves, the time required for driving a minute distance is greatly related to the shutter speed.
However, when the actuator structure is driven by a piezoelectric element, ringing due to natural vibration of the actuator structure occurs, and it takes time to reach a static state.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a drive control system that minimizes ringing and quickly stabilizes an actuator structure.

In order to solve the above problems, a drive control system of the present invention includes a first actuator unit that drives a driven carrier in one direction, a first piezoelectric element that applies a driving force to the first actuator unit, A second actuator unit that drives one actuator unit in one direction, a second piezoelectric element that applies a driving force to the second actuator unit, a first driver that applies a driving voltage to the first piezoelectric element, And a second driver for applying a driving voltage to the second piezoelectric element.
The control unit gives a drive control signal with a time difference to the first driver and the second driver, and when driving one of the plurality of piezoelectric elements connected to the control unit, A time difference obtained by dividing the time corresponding to the wavelength of ringing generated in the second actuator unit by the number of the plurality of piezoelectric elements is given to the drive control signal .

According to the present invention, it is possible to provide a drive control system that suppresses ringing of an actuator structure to a minimum and quickly settles.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is an external appearance perspective view of the camera unit which has an actuator structure in connection with embodiment of this invention. It is a disassembled perspective view of the camera unit which has an actuator structure in connection with embodiment of this invention. It is a top view of an actuator unit. It is explanatory drawing which drawn the part except an inner side carrier and a leaf | plate spring among actuator units with the dotted line. It is a schematic block diagram of the drive control system of a camera unit. It is a circuit diagram of a driver. It is a time chart which shows the displacement of an on-off control signal, the voltage applied to a piezoelectric element, and an actuator unit. It is a time chart for demonstrating a mode that the ringing of an actuator unit is canceled.

[Appearance and structure of actuator structure]
FIG. 1 is an external perspective view of a camera unit having an actuator structure according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view of a camera unit having an actuator structure according to the embodiment of the present invention.
The camera unit 101 includes an image sensor substrate 102, a first actuator 103, a second actuator 104, a third actuator 105, a fourth actuator 106, and a base 107.
An image sensor 108 is fixed to the center of the image sensor substrate 102. The image sensor substrate 102 is screwed to the first actuator 103.
The first actuator 103 is screwed to the second actuator 104.
The second actuator 104 is screwed to the third actuator 105.
The third actuator 105 is screwed to the fourth actuator 106.
The fourth actuator 106 is screwed to the base 107.

The first actuator 103, the second actuator 104, the third actuator 105, and the fourth actuator 106 have exactly the same shape. Hereinafter, the first actuator 103, the second actuator 104, the third actuator 105, and the fourth actuator 106 are collectively referred to as an actuator unit 301. An assembly of the first actuator 103, the second actuator 104, the third actuator 105, and the fourth actuator 106 is referred to as an actuator structure 109. That is, the camera unit 101 includes the image sensor substrate 102, the actuator structure 109, and the base 107.
When each actuator unit 301 is screwed, it is screwed with a washer (not shown) interposed therebetween. Therefore, a gap corresponding to the thickness of the washer exists between the actuator units 301, between the imaging element substrate 102 and the first actuator 103, and between the fourth actuator 106 and the base 107. Due to the existence of these gaps, the actuator units 301, the image sensor substrate 102, the first actuator 103, the fourth actuator 106, and the base 107 can be relatively displaced by a piezoelectric element that will be described later with reference to FIG. It is.
By driving the actuator structure 109 by a minute distance in the vertical direction and the horizontal direction, higher resolution than the distance between the optical sensors constituting the image sensor 108 can be realized.

FIG. 3 is a top view of the actuator unit 301.
FIG. 4 is an explanatory diagram in which portions of the actuator unit 301 excluding the inner carrier and the leaf spring are drawn with dotted lines.
The actuator unit 301 is formed by cutting square stainless steel having a thickness of 2.5 mm. Note that the shape of the actuator unit 301 is not necessarily square.
The actuator unit 301 is divided into an outer edge container 302, an inner carrier 303, and leaf springs 304a, 304b, 304c, and 304d by the cutting process. A driving space S305 is provided between the outer edge container 302 and the inner carrier 303, and a piezoelectric element P615 is press-fitted into the driving space S305.
The two screw holes H306 and H307 provided in the inner carrier 303 are tapered so that the head of a countersunk screw (not shown) is fitted.
The two screw holes H308 and H309 provided in the outer edge container 302 are processed with screw grooves corresponding to the countersunk screw shafts.
A line L310 connecting two screw holes H308 and H309 provided in the outer edge container 302 is parallel to the moving direction of the outer edge container 302. The outer edge container 302 and the inner carrier 303 are formed symmetrically with respect to the line L310.

  As can be seen from FIG. 4, the actuator unit 301 is screwed into the screw hole of the base 107 on which the screw hole of the inner carrier 303 is arranged on the lower side or the outer container of the other actuator unit 301. When a DC voltage of about +80 V, for example, is applied to the piezoelectric element P615, the piezoelectric element P615 expands in the direction of the arrow parallel to the line. Then, since the inner carrier 303 is screwed to another member, the outer edge container 302 relatively moves in the direction of the arrow. In the case of the actuator unit 301 of the present embodiment, the actuator unit 301 can move relatively by a maximum of about 17 μm. Further, the amount of displacement can be controlled by controlling the voltage applied to the piezoelectric element P615.

As can be seen from FIG. 2, the first actuator 103 is fixed in a direction perpendicular to the arrangement of the second actuator 104.
Similarly, the second actuator 104 is fixed in a direction perpendicular to the arrangement of the third actuator 105. The third actuator 105 is fixed in a direction perpendicular to the arrangement of the fourth actuator 106.
Here, the first actuator 103 and the third actuator 105 drive the outer edge container 302 in the direction of the arrow R205 in FIG. 2, and similarly, the second actuator 104 and the fourth actuator 106 move the outer edge container 302 to the arrow R205. Note that the drive is orthogonal and in the direction of arrow R206 in FIG.

The actuator unit 301 is required to be line symmetric with respect to the dotted line in FIG. 3 in order to realize strict linear movement.
For example, the plate springs 304a, 304b, 304c, and 304d may not be arranged in a square shape as shown in FIG. 3, for example, at positions corresponding to the vertices of the trapezoid. May be. However, since it must be line symmetric, a non-line symmetric arrangement such as a parallelogram is not desirable.

[Configuration of drive control system and driver]
FIG. 5 is a schematic block diagram of the drive control system 501 of the camera unit 101.
When the command information is transmitted from the command information output device 502 such as a personal computer, the first control unit 503 configured by an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) or the like includes the first driver 504 and the first driver 504. A control signal for driving the piezoelectric element P615 is output to the three driver 505.
The first driver 504 and the second driver are configured by exactly the same circuit, and a drive voltage of about +80 V, for example, is applied to the piezoelectric element P615 according to the control signal.
The first driver 504 applies a driving voltage to the first piezoelectric element P201 press-fitted into the first actuator 103.
The third driver 505 applies a driving voltage to the third piezoelectric element P203 press-fitted into the third actuator 105.
The first control unit 503 includes a first control signal generation unit 506, a second control signal generation unit 507, and a delay 508.
The delay 508 delays the output timing of the command information input from the command information output device 502 by a time corresponding to a half period of the natural vibration frequency of the actuator structure 109.

In addition to the first control unit 503, a second control unit 509 is also connected to the command information output device 502.
The second control unit 509 has the same internal configuration as the first control unit 503.
When the command information output device 502 transmits the command information, the second control unit 509 outputs a control signal for driving the piezoelectric element P615 to the second driver 510 and the fourth driver 511.
The second driver 510 and the fourth driver 511 are configured by the same circuit as the first driver 504 described above.
The second driver 510 applies a driving voltage to the second piezoelectric element P202 press-fitted into the second actuator 104.
The fourth driver 511 applies a drive voltage to the fourth piezoelectric element P204 press-fitted into the fourth actuator 106.
Hereinafter, the first driver 504, the third driver 505, the second driver 510, and the fourth driver 511 are collectively referred to as a driver 601.

FIG. 6 is a circuit diagram of the driver 601.
A DC drive voltage E601 (+80 V) is applied to the resistors R602 and R603.
When the transistor switch Q604 is turned on, a voltage divided by the resistors R602 and R605 is applied to the gate of the FET Q606.
When the transistor switch Q607 is turned on, a voltage divided by the resistors R602 and R608 is applied to the gate of the FET Q606.
Either or both of the transistor switches Q604 and Q607 are turned on / off.
Since the resistance values of the resistors R605 and R608 are different, the voltage applied to the gate of the FET Q606 changes depending on which of the transistor switches Q604 and Q607 is on-controlled.

A drive voltage E601 is applied to the drain of the FET Q606 through a resistor R603.
The emitter of the transistor switch Q609 is connected to the source of the FET Q606.
A resistor R610 is connected to the emitter and base of the transistor switch Q609.
A transistor switch Q612 is connected to the base of the transistor switch Q609 through a resistor R611.
A capacitor C613, a resistor R614, and a piezoelectric element P615 are connected to the collector of the transistor switch Q609.
The collector of the transistor switch Q616 is connected to the resistor R614.
Transistor switches Q604, Q607, Q612, and Q616 are each supplied with + 5V through resistors R617, R618, R619, and R620.

[Operation]
The operation of the driver 601 in FIG. 6 will be described with reference to FIG.
FIGS. 7A, 7 </ b> B, and 7 </ b> C are time charts showing the on / off control signal, the voltage applied to the piezoelectric element P <b> 615, and the displacement of the actuator unit 301.
FIG. 7A shows an excerpt of the on / off control signal for the transistor switch Q609 from the command information output by the command information output device 502. FIG.
FIG. 7B is a waveform of a voltage applied to the piezoelectric element P615.
When charging the capacitor C613, Q604 or Q607 is turned on at time t701, Q612 is turned on, and Q616 is turned off.
Then, the capacitor C613 is charged, and the potential (substantially equal to the potential of the source of Q606) rises to the time point t702. The slope of the potential rise is determined by the time constant formed by the resistor R603 and the capacitor C613.
When the potential of the source of the FET Q606 becomes equal to the potential of the gate of the Q606, the Q606 is controlled to be off. Therefore, the voltage divided by the resistor R602 and the resistor R605 is the source voltage of the FET Q606.
When discharging the capacitor C613, Q604 and Q607 may be turned off or on, but Q612 is turned off and Q616 is turned on.
When Q612 is turned off at time t703, the base potential of Q609 becomes the same as that of the emitter by the resistor R610, and the base current stops flowing, so that Q609 is controlled to be off.
When Q616 is turned on at time t703, the charge remaining in the capacitor C613 and the piezoelectric element P615 is discharged through R614 until time t704. The slope of the potential of the capacitor C613 that decreases due to the discharge is determined by the time constant formed by the resistor R614 and the capacitor C613.

As shown in FIG. 7B, in the ON operation in which a voltage is applied to the piezoelectric element P615, the potential increases with a predetermined slope depending on the time constant formed by the resistor R603 and the capacitor C613. Then, in the off operation for releasing the voltage applied to the piezoelectric element P615, the potential decreases with a predetermined slope depending on the time constant formed by the resistor R614 and the capacitor C613. The inclination of the drive voltage is provided to suppress the ringing because strong ringing occurs when an abrupt force is applied to the actuator unit 301.
However, the displacement of the actuator unit 301 that is actually driven by the piezoelectric element P615 is accompanied by the ringing R705 as shown in FIG. 7C, even if the driving voltage of the piezoelectric element P615, in turn, tilts the driving force. . This ringing R705 matches the resonance frequency of the actuator unit 301. The piezoelectric element P615 has a role like a hammer that strikes the actuator unit 301. Since this ringing R705 occurs, the actuator unit 301 cannot stabilize the position until the ringing R705 is settled.
Therefore, in order to suppress this ringing R705, two actuators that drive in the same direction are provided, and from the time when one of the actuators is driven, it is delayed by a time corresponding to a half wavelength of the resonance frequency of the actuator unit 301 and Drive the actuator.

8A, 8B, and 8C are time charts for explaining how the ringing of the actuator unit 301 is canceled.
FIG. 8A is a time chart showing the displacement of the first actuator 103.
FIG. 8B is a time chart showing the displacement of the third actuator 105.
As shown in FIG. 2, the first actuator 103 and the third actuator 105 drive the outer edge container 302 in the same direction.
Now, at time t801 in FIG. 8A, the first actuator 103 is driven. The third actuator 105 is driven at a time point t802 delayed by a time corresponding to a half wavelength of the ringing frequency of the actuator unit 301. Then, since the frequency component of the ringing is opposite in phase, the ringing component disappears as shown in FIG. 8C and the displacement amount of the two actuator units 301 is added. The As a result, the settling time of the image pickup device substrate 102 which is a driven carrier is shortened, and the displacement amount of the minute piezoelectric element P615 can be doubled.

  From the above description, in order to effectively cancel the ringing of the actuator unit 301, it is desirable that the piezoelectric elements P615 press-fitted into the first actuator 103 and the third actuator 105 have the same shape. It is necessary to apply the same voltage to cause stretching deformation of the same distance.

In the embodiment described above, the following application examples are possible.
(1) The material of the actuator unit 301 is not limited to stainless steel. From the viewpoint of cutting and forming the leaf springs 304a, 304b, 304c, and 304d, it is desirable that the metal be elastic. As an example, iron or brass can be considered.

  (2) Although the camera unit 101 is disclosed in the present embodiment, the target driven by the actuator structure 109 is not limited to the image sensor 108. As an example, if it is a member related to optical equipment, it is conceivable to attach a light projection element such as a light emitting element such as a laser diode or a polarizing filter.

  (3) The actuator unit 301 of the present embodiment has a configuration in which the inner carrier 303 is fixed to another member and the outer edge container 302 is driven by the piezoelectric element P615. Since this driving relationship is relative, the inner carrier 303 may be driven in a state where the outer edge container 302 is fixed.

  (4) The actuator structure 109 of this embodiment cancels ringing using two actuator units 301. The ringing cancellation process is not limited to two stages, and a plurality of stages of three or more stages may be used. As an example, if the ringing wavelength is λ in the case of three stages, the ringing is delayed by a time corresponding to λ / 3 (λ corresponding to the number of stages). That is, a time delay corresponding to λ / 3 is set for the second piezoelectric element, and a time delay corresponding to 2λ / 3 is set for the third piezoelectric element.

In the present embodiment, the drive control system 501 that drives the actuator structure 109 has been disclosed.
The first piezoelectric element P201 that drives the first actuator 103 and the third piezoelectric element that drives the third actuator 105 in order to reduce ringing that occurs from the actuator structure 109 driven by the piezoelectric element P615 for a minute distance. The timing for driving the element P203 is relatively shifted by a time corresponding to a half wavelength of the natural vibration frequency of the actuator structure 109. The ringing generated from the first actuator 103 is canceled by the ringing generated with a half wavelength delay from the third actuator 105, and as a result, the settling time of the driven carrier is shortened.

The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and other modifications may be made without departing from the gist of the present invention described in the claims. Includes application examples.
For example, the above-described exemplary embodiments are detailed and specific descriptions of the configuration of the apparatus and system in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. . Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
Each of the above-described configurations, functions, processing units, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Further, each of the above-described configurations, functions, and the like may be realized by software for interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function is stored in a memory, a hard disk, a volatile or non-volatile storage such as an SSD (Solid State Drive), or a recording medium such as an IC card or an optical disk. be able to.
In addition, the control lines and information lines are those that are considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

  DESCRIPTION OF SYMBOLS 101 ... Camera unit, 102 ... Image sensor board | substrate, 103 ... 1st actuator, 104 ... 2nd actuator, 105 ... 3rd actuator, 106 ... 4th actuator, 107 ... Base, 108 ... Image sensor, 109 ... Actuator structure , P201 ... first piezoelectric element, P202 ... second piezoelectric element, P203 ... third piezoelectric element, P204 ... fourth piezoelectric element, 301 ... actuator unit, 302 ... outer edge container, 303 ... inner carrier, 304a, 304b, 304c, 304d ... leaf spring, H306, H307, H308, H309 ... screw hole, 501 ... drive control system, 502 ... command information output device, 503 ... first control unit, 504 ... first driver, 505 ... third driver, 506 ... First control signal generation unit, 507, second control signal generation unit, 508 Delay, 509 ... second control unit, 510 ... second driver, 511 ... fourth driver, 601 ... driver, Q606 ... FET, Q604, Q607, Q609, Q612, Q616 ... transistor switch, R602, R603, R605, R608, R610, R611, R614, R617 ... resistor, C613 ... capacitor, P615 ... piezoelectric element

Claims (3)

A first actuator unit for driving the driven carrier in one direction;
A first piezoelectric element for applying a driving force to the first actuator unit;
A second actuator unit for driving the first actuator unit in the one direction;
A second piezoelectric element for applying a driving force to the second actuator unit;
A first driver for applying a driving voltage to the first piezoelectric element;
A second driver for applying a driving voltage to the second piezoelectric element;
A controller that provides a drive control signal with a time difference to the first driver and the second driver ;
The control unit sets a time corresponding to a wavelength of ringing generated in the first actuator unit and the second actuator unit when driving any one of the plurality of piezoelectric elements connected to the control unit. A time difference divided by the number of piezoelectric elements is given to the drive control signal.
Drive control system. The first actuator unit includes:
A carrier made of metal,
A container made of metal of the same material as the carrier;
Wherein interposed between the carrier and the container comprises a plate spring made of a metal of the same material as the carrier, the drive control system according to claim 1, wherein. The drive control system according to claim 2 , wherein four leaf springs are provided at positions symmetrical with respect to a line parallel to a drive direction of the driven carrier.

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