JP2013174677A - Piezoelectric actuator drive system and video device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric actuator drive system and a video device which can improve an S/N ratio of a detection signal output according to operation of a piezoelectric actuator.SOLUTION: A piezoelectric actuator drive system includes a piezoelectric actuator and a substrate connected to the piezoelectric actuator. A buffer unit is arranged near the piezoelectric actuator, and receives input of a detection signal output from the piezoelectric actuator according to operation of the piezoelectric actuator.

Description

  The present invention relates to a piezoelectric actuator driving system and a video apparatus having a piezoelectric actuator and a substrate connected to the piezoelectric actuator.

  2. Description of the Related Art Conventionally, a piezoelectric actuator driving system that drives a piezoelectric actuator built in a micro electro mechanical system (MEMS) is known. For example, Patent Literature 1 and Patent Literature 2 describe a piezoelectric actuator and driving means for driving the piezoelectric actuator. A conventional piezoelectric actuator drive system will be described below.

  FIG. 1 is a diagram showing an example of a conventional piezoelectric actuator drive system. The piezoelectric actuator drive system 10 of FIG. 1 is provided on a MEMS unit 1 having a built-in piezoelectric actuator, an FPC (Flexible Printed Circuit) cable 3 that connects the MEMS unit 1 and the substrate 2, and the substrate 2. An FPC connector 4, a buffer unit 5, and a drive unit 6 are included.

  FIG. 2 is a diagram illustrating signals of a conventional MEMS unit driving system. A detection signal from the MEMS unit 1 is supplied to the buffer unit 5 of the substrate 2. A drive signal for driving the piezoelectric actuator is supplied from the drive unit 5 of the substrate 2 to the MEMS unit 1. The detection signal is a signal output from a piezoelectric sensor provided in a piezoelectric actuator built in the MEMS unit 1. The piezoelectric sensor outputs a detection signal corresponding to the displacement of the piezoelectric actuator.

  FIG. 3 is a diagram illustrating a configuration example of a conventional buffer unit. In the buffer unit 5, for example, an SS1 signal and an SS1G signal, which are one system of detection signals, are input to the I / V amplifier 7, and are subjected to charge (current) -voltage conversion and output as Vout.

  FIG. 4 is a diagram for explaining an input signal and an output signal to a conventional MEMS unit. The substrate 2 outputs a drive signal for driving the piezoelectric actuator to the MEMS unit 1 by the signal lines SD1, SD1G, SD2, SD2G, MD, and MDG. The MEMS unit 1 outputs a detection signal to the substrate 2 for detecting the displacement of the piezoelectric actuator through the signal lines SS1, SS1G, SS2, SS2G, MS, MSG.

  The drive signal and the detection signal are output from the MEMS unit 1 to the substrate 2 or from the substrate 2 to the MEMS unit 1 via the FPC cable 3 and the FPC connector 4.

  When the displacement of the piezoelectric actuator is detected by the piezoelectric sensor, the piezoelectric sensor is necessarily adjacent to the piezoelectric element that displaces the piezoelectric actuator. Therefore, when the MEMS unit 1 and the substrate 2 are connected by the FPC cable 3 and the FPC connector 4, the drive signal is superimposed on the detection signal side as crosstalk, and the detection signal is deteriorated.

  Further, the detection signal output from the piezoelectric sensor has a poor S / N ratio when the operating frequency of the piezoelectric actuator is lowered, and is difficult to detect with a general circuit configuration.

  The present invention has been made to solve this problem in view of the above circumstances, and a piezoelectric actuator drive system capable of improving the S / N ratio of a detection signal output according to the operation of the piezoelectric actuator, and The object is to provide a video device.

  In order to achieve the above object, the present invention employs the following configuration.

  The present invention is a piezoelectric actuator drive system having a piezoelectric actuator and a substrate connected to the piezoelectric actuator, and is disposed in the vicinity of the piezoelectric actuator, and the piezoelectric actuator is operated according to the operation of the piezoelectric actuator. Has a buffer unit to which a detection signal output from is input.

  In the piezoelectric actuator drive system of the present invention, the output of the buffer unit is connected to an amplifier unit provided on the substrate.

The present invention is a video apparatus that includes a piezoelectric actuator that swings a mirror and a substrate connected to the piezoelectric actuator, and that scans the light applied to the mirror to display an image, and the piezoelectric actuator And a buffer unit to which a detection signal output from the piezoelectric actuator is input according to the operation of the piezoelectric actuator,
The output of the buffer unit is connected to an amplifier unit provided on the substrate.

  According to the present invention, the S / N ratio of the detection signal output according to the operation of the piezoelectric actuator can be improved.

It is a figure which shows the example of the conventional piezoelectric actuator drive system. It is a figure explaining the signal of the conventional MEMS unit drive system. It is a figure which shows the structural example of the conventional buffer part. It is a figure explaining the input signal and output signal to the conventional MEMS unit. It is a figure explaining the piezoelectric actuator drive system of this invention. It is a 1st figure explaining a piezoelectric actuator. It is a figure explaining a drive beam and a piezoelectric sensor. It is a figure explaining the signal wire | line connected to a piezoelectric actuator. It is a 1st figure explaining the drive signal supplied to a piezoelectric actuator. It is a 2nd figure explaining the drive signal supplied to a piezoelectric actuator. It is a figure explaining the connection of a piezoelectric actuator and a board | substrate. It is a figure explaining a buffer part. It is a figure explaining an instrumentation amplifier part. It is an example of the MEMS unit which has a buffer part.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is a diagram for explaining the piezoelectric actuator drive system of the present invention.

  The piezoelectric actuator driving system 100 according to the present embodiment includes a MEMS unit 110, a buffer unit 120, an FPC (Flexible Printed Circuit) cable 130, a substrate 140, an FPC connector 150, an instrumentation amplifier unit 160, and a driving unit 170. .

  The MEMS unit 110 of the piezoelectric actuator drive system 100 of this embodiment incorporates a piezoelectric actuator. A buffer unit 120 is connected to the MEMS unit 110 of the present embodiment. Specifically, in the present embodiment, a substrate on which a buffer unit 120 that performs current-voltage conversion is mounted is directly connected to the MEMS unit 110. The buffer unit 120 of the present embodiment is preferably arranged as close to the MEMS unit 110 as possible.

  The buffer unit 120 of the present embodiment is connected to the substrate 140 via the FPC cable 130. An FPC connector 150 is mounted on the substrate 140, and an FPC cable 130 is connected thereto. An instrumentation amplifier unit 160 and a drive unit 170 are mounted on the substrate 140.

  The instrumentation amplifier 160 receives a signal output from the MEMS unit 110 via the FPC cable 130 and the FPC connector 150. The driving unit 170 outputs a signal for driving the piezoelectric actuator to the MEMS unit 110 via the FPC cable 130 and the FPC connector 150. Details of signals input and output between the MEMS unit 110 and the substrate 140 will be described later.

  Next, the piezoelectric actuator built in the MEMS unit 110 of this embodiment will be described with reference to FIGS.

  FIG. 6 is a first diagram illustrating the piezoelectric actuator.

  The piezoelectric actuator 200 of this embodiment uses a piezoelectric element. It is known that a piezoelectric element exhibits a reverse piezoelectric effect that causes a distortion proportional to the applied voltage potential, that is, expansion and contraction, when a voltage is applied in the polarization direction. The piezoelectric actuator 200 of this embodiment is configured to transmit a driving force to a driven body using this piezoelectric element.

  For example, the piezoelectric element used in the piezoelectric actuator 200 of the present embodiment exhibits a driving force in a state of being polarized in one direction like a permanent magnet, and electrodes are formed on both end faces in the polarization direction. A driving force is obtained by supplying a driving voltage between the electrodes.

  The above-described polarization can be obtained by applying a certain DC voltage for a certain time in consideration of the composition of the element. An element once polarized is generally driven by applying a voltage between the voltage direction in which the polarization is applied and zero.

  The piezoelectric actuator 200 of the present embodiment scans the light irradiated on the mirror 230 by swinging the mirror 230 in two directions, the X-axis direction and the Y-axis direction. The piezoelectric actuator 200 of this embodiment includes a frame 210, torsion bars 211 and 212, a frame 220, a support beam 221, a mirror 230, driving beams 241, 242, 243, 244, 261, and 262, piezoelectric sensors 251, 252, 253, 254, 271 and 272.

  In the piezoelectric actuator 200 of the present embodiment, the frame 210 is a piezoelectric actuator frame formed on a silicon substrate. The frame 220 is connected to and supported by the frame 210 by torsion bars 211 and 212. The mirror 230 is supported by a support beam 221 connected to the frame 220.

  The driving beams 241 and 242 are connected to the frame 210 and the torsion bar 211, and the driving beams 243 and 244 are connected to the frame 210 and the torsion bar 212. In the present embodiment, the frame 220 operates in a direction twisting around the torsion bars 211 and 212 (direction rotating around the Y axis) by expansion and contraction of the piezoelectric elements formed on the drive beams 241 to 244.

  In the present embodiment, the piezoelectric sensors 251 and 252 whose one ends are supported by the torsion bar 211 and the piezoelectric sensors 253 and 254 whose one ends are supported by the torsion bar 212 are provided. Each piezoelectric sensor of the present embodiment is a means for detecting the operation of the piezoelectric actuator 200. The piezoelectric sensors 251 and 252 output a detection signal corresponding to the twist of the torsion bar 211. The electric sensors 253 and 254 output detection signals corresponding to the twist of the torsion bar 212.

  Furthermore, the piezoelectric actuator 200 according to the present embodiment includes drive beams 261 and 262 connected to the frame 220 and the support beam 221. In this embodiment, the frame 220 operates in a direction twisting around the support beam 221 (direction rotating around the X axis) by expansion and contraction of the piezoelectric elements formed on the drive beams 261 and 262.

  In the piezoelectric actuator 200 of the present embodiment, the angle of the mirror 230 is displaced by the twist of the frame 220 in the Y-axis direction and the X-axis direction, and the light irradiated on the mirror 230 is scanned.

  The drive beams 241 to 244, 261 and 262, and the piezoelectric sensors 251 to 254, 271 and 272 according to this embodiment will be described below with reference to FIG. FIG. 7 is a diagram illustrating the driving beam and the piezoelectric sensor.

  The drive beam 241 of this embodiment includes a diaphragm 241A, a piezoelectric element 241B formed on the top of the diaphragm 241A, and a lower electrode 241C formed on the back surface of the diaphragm 241A. In this embodiment, the piezoelectric element 241B is displaced by applying a driving voltage to the signal line SD (Sub Drive) 1 connected to the piezoelectric element 241B and the signal line SD1G connected to the lower electrode 241C.

  The drive beams 242, 243, 244, 261, and 262 of the present embodiment have the same configuration.

  The piezoelectric sensor 251 of the present embodiment includes a diaphragm 251A, a piezoelectric element 251B formed on the top of the diaphragm 251A, and a lower electrode 251C formed on the back surface of the diaphragm 251A, and is positioned adjacent to the drive beam 241. Provided. In the piezoelectric sensor 251 of this embodiment, the piezoelectric element 251 </ b> B is displaced by the torsion bar 211 being twisted by the driving beam 241. When the piezoelectric element 251B is displaced, an electric charge is charged between the piezoelectric element 251B and the lower electrode 251C, and a potential difference is generated between the piezoelectric element 251B and the lower electrode 251C. In the present embodiment, a potential difference generated between the piezoelectric element 251B and the lower electrode 251C from the signal line SS (Sub Sense) 1 connected to the piezoelectric element 251B and the signal line SS1G connected to the lower electrode 251C is determined. Obtained as a detection signal.

  The piezoelectric sensors 252, 253, 254, 271, and 272 of the present embodiment have the same configuration.

  FIG. 8 is a diagram illustrating signal lines connected to the piezoelectric actuator.

  In the piezoelectric actuator 200 of this embodiment, the signal line SD1 is connected to the piezoelectric element 241B of the driving beam 241 and the piezoelectric element 243B of the driving beam 243. Although not shown in FIG. 8, the signal line SD1G is connected to the lower electrode of each of the drive beam 241 and the drive beam 243. In the present embodiment, the voltage between the signal lines SD1 and SD1G is supplied as the drive voltage for the drive beams 241 and 243.

  In addition, the signal line SD2 is connected to the piezoelectric element 242B of the driving beam 242 and the piezoelectric element 244B of the driving beam 244 according to the present embodiment. Although not shown in FIG. 8, a signal line SD2G is connected to the lower electrode of each of the driving beam 242 and the driving beam 244. In the present embodiment, the voltage between the signal lines SD2 and SD2G is supplied as the drive voltage for the drive beams 242 and 244.

  Further, a signal line MD (Main Drive) is connected to the piezoelectric element 261B of the driving beam 261 and the piezoelectric element 262B of the driving beam 262 of the present embodiment. Although not shown in FIG. 8, a signal line MDG is connected to the lower electrode of each of the driving beam 261 and the driving beam 262. In the present embodiment, the voltage between the signal lines MD and MDG is supplied as the drive voltage for the drive beams 261 and 262.

  In this embodiment, the driving voltage supplied to each driving beam is output from the driving unit 170 of the substrate 140 and supplied to the piezoelectric actuator 200.

  In the piezoelectric actuator 200 of the present embodiment, the signal line SS1 is connected to the piezoelectric element 251B of the piezoelectric sensor 251 and the piezoelectric element 253B of the piezoelectric sensor 253. Although not shown in FIG. 8, the signal line SS1G is connected to the lower electrode of each of the piezoelectric sensor 251 and the piezoelectric sensor 253. In the present embodiment, the potential difference between the signal line SS1 and the signal line SS1G is used as a detection signal for detecting the displacement of the piezoelectric element 241B and the piezoelectric element 243B. The detection signal is output from the piezoelectric actuator 200 and supplied to the buffer unit 120.

  In the piezoelectric actuator 200 of the present embodiment, the signal line SS2 is connected to the piezoelectric element 252B of the piezoelectric sensor 252 and the piezoelectric element 254B of the piezoelectric sensor 254. Although not shown in FIG. 8, the signal line SS2G is connected to the lower electrode of each of the piezoelectric sensor 252 and the piezoelectric sensor 254. In the present embodiment, the potential difference between the signal lines SS2 and SS2G is used as a detection signal for detecting the displacement of the piezoelectric element 242B and the piezoelectric element 244B. The detection signal is output from the piezoelectric actuator 200 and supplied to the buffer unit 120.

  In the piezoelectric actuator 200 of this embodiment, a signal line MS (Main Sense) is connected to the piezoelectric element 271B of the piezoelectric sensor 271 and the piezoelectric element 272B of the piezoelectric sensor 272. Although not shown in FIG. 8, a signal line MSG is connected to the lower electrode of each of the piezoelectric sensor 271 and the piezoelectric sensor 272. In the present embodiment, the potential difference between the signal lines MS and MSG is used as a detection signal for detecting the displacement of the piezoelectric element 261B and the piezoelectric element 262B. The detection signal is output from the piezoelectric actuator 200 and supplied to the buffer unit 120.

  The drive signals of this embodiment will be described below with reference to FIGS. FIG. 9 is a first diagram illustrating a drive signal supplied to the piezoelectric actuator.

  FIG. 9 shows a drive signal when the frame 220 is rotated about the Y axis. In FIG. 9, a drive signal 91 that is a signal between SD1 and SD1G, a drive signal 92 that is a signal between SD2 and SD2G, a drive beam 241 to which the drive signal 91 is supplied, and a drive to which the drive signal 92 is supplied. The relationship between the beam 243 and the torsion bar 211 is shown.

  The drive signal 91 and the drive signal 92 are signals whose phases are inverted by 180 degrees. In FIG. 9, at time t1, the voltage between SD1 and SD1G is zero, and the voltage between SD2 and SD2G is maximum. The driving beam 241 and the driving beam 243 have zero displacement of the piezoelectric element 241B in the driving beam 241 on the left side of the torsion bar 211 as the center (axis), as shown in the schematic diagram below the time t1. Further, in the drive beam 243 on the right side of the torsion bar 211, the displacement of the piezoelectric element 243B is contracted to the maximum. Therefore, the torsion bar 211 is tilted to the right (maximum twist).

  At time t2, both of the drive beams 241 and 243 are in a direction in which the piezoelectric elements 241B and 243B contract in the middle, and the inclination (twist) of the torsion bar 211 becomes zero.

  At time t3, the piezoelectric element 241B contracts to the maximum in the driving beam 241 on the left side of the torsion bar 211, and the displacement of the piezoelectric element 243B becomes zero in the driving beam 243 on the right side of the torsion bar 211. Therefore, the torsion bar 211 is tilted (twisted) to the left to the maximum.

  Note that the relationship between the torsion bar 212 and the drive beams 242 and 244 is the same as the relationship between the torsion bar 211 and the drive beams 241 and 243, and thus the description thereof is omitted.

  The piezoelectric actuator 200 of this embodiment rotates the mirror 300 about the Y axis as described above.

  FIG. 10 is a second diagram illustrating the drive signal supplied to the piezoelectric actuator.

  FIG. 10 shows a drive signal when the mirror 300 is rotated about the X axis. FIG. 10 shows the relationship between the drive signal 93 that is a signal between MD and MDG, the drive beam 261 supplied with the drive signal 93, and the support beam 221.

  In FIG. 10, the voltage between MD and MDG is zero at time t1. At this time, in the piezoelectric actuator 200, the displacement of the piezoelectric element 261B becomes zero on the left side of the support beam 221 at the center, as shown in the schematic diagram below the reference numeral t1. At time t2, the piezoelectric element 261B is contracted in the middle, and the inclination (twist) of the support beam 221 is slightly inclined to the left. At time t3, the piezoelectric element 261B is contracted to the maximum on the left side of the support beam 221, and the support beam 221 is tilted to the left to the maximum.

  In the piezoelectric actuator 200 of the present embodiment, the mirror 300 is thus rotated about the X axis.

  As described above, the drive beams 241 to 244 of the piezoelectric actuator 200 of this embodiment are physically deformed in the piezoelectric elements 241B to 244B with the torsion bar 211 as the center. Therefore, the piezoelectric elements 251B to 254B of the piezoelectric sensors 251 to 254 adjacent to each drive beam are charged with electric charges according to this force, and a voltage is generated.

  The drive beams 261 and 261 are physically deformed in the piezoelectric elements 261B and 262B with the support beam 221 as the center. Therefore, the piezoelectric elements 271B and 272B of the piezoelectric sensors 271 and 272 adjacent to each drive beam are charged with electric charges according to this force, and a voltage is generated.

  This voltage is output from the piezoelectric actuator 200 as a detection signal.

  The connection between the piezoelectric actuator 200 of this embodiment and the substrate 140 will be described below with reference to FIG. FIG. 11 is a diagram illustrating the connection between the piezoelectric actuator and the substrate.

  In the piezoelectric actuator drive system 100 of the present embodiment, a drive signal for the piezoelectric actuator 200 is output from the drive unit 140 provided on the substrate 140 and supplied to the MEMS unit 110. In the piezoelectric actuator drive system 100 of this embodiment, the buffer unit 120 is connected to the subsequent stage of the MEMS unit 110, and the detection signal output from the MEMS unit 110 is input to the buffer unit 120.

  The detection signal input to the buffer unit 120 is output to the instrumentation amplifier unit 160 provided on the substrate 140 as a buffer output. The buffer unit 120 is supplied with power and GND from the substrate 140.

  In this embodiment, as described above, the buffer unit 120 is provided in the subsequent stage of the MEMS unit 110, and the detection signal is stored in the buffer unit 120, so that the parallel wiring of the detection signal and the drive signal that are easily affected by noise is minimized. can do. Therefore, according to the present embodiment, it is possible to minimize the influence of crosstalk on the detection signal.

  Hereinafter, the buffer unit 120 and the instrumentation amplifier unit 160 according to this embodiment will be described with reference to FIGS. FIG. 12 is a diagram illustrating the buffer unit.

  The buffer unit 120 of this embodiment includes a current-voltage conversion (I / V) amplifier 121 and a voltage follower circuit 122. The I / V amplifier 121 of this embodiment is provided on the signal line SS1 side, and the voltage follower circuit 122 is provided on the signal line SSG1 side (GND side).

  In the I / V amplifier 121 of this embodiment, the signal line SS1 is connected to the inverting input terminal and the signal line SS1G is connected to the non-inverting input terminal, and the current extracted from the signal line SS1 is amplified and converted into a voltage. . That is, the I / V amplifier 121 outputs, as the detection signal SS1out, a signal obtained by changing the charge charged between the piezoelectric element 251B and the lower electrode 251C of the piezoelectric sensor 251 to a voltage.

  The signal line SS1 of the present embodiment is a chargeable output from the piezoelectric element. Therefore, in the present embodiment, the charge / voltage conversion, that is, the equivalent current-voltage conversion (I / V conversion) is performed by the I / V amplifier 121 to output a chargeable output as a voltage. Can do.

  The voltage follower circuit 122 of this embodiment functions as a voltage buffer, and the non-inverting input terminal of the amplifier 123 is connected to the signal line SS1G. The non-inverting input terminal of the amplifier 123 is connected to the reference potential terminal GNDsig. The reference potential at the reference potential terminal GNDsig is obtained from the substrate 140. The inverting input terminal of the amplifier 123 is connected to the output of the amplifier 123. The output of the amplifier 123 is output as the signal SS1Gout.

  In the present embodiment, the voltage follower circuit 122 is provided on the signal line SS1G side, and the signal SS1Gout from which the noise component at the GND point is removed can be output by removing noise superimposed on the reference potential terminal GNDsig.

  As described above, in the present embodiment, the detection signal knowledge SS1out on the signal line SS1 side and the signal SS1Gout on the signal line SS1G side are output from the buffer unit 120.

  FIG. 13 is a diagram illustrating the instrumentation amplifier unit.

  The instrumentation amplifier unit 160 of the present embodiment receives the detection signal SS1out output from the buffer unit 120 and the signal SS1Gout from which noise has been removed.

  The instrumentation amplifier 160 of this embodiment includes amplifiers 161, 162, and 163. The detection signal SS1out is input to the non-inverting input terminal of the amplifier 161. The inverting input terminal of the amplifier 161 is connected to the inverting input terminal of the amplifier 162 via the resistor R1. The inverting input terminal of the amplifier 161 is connected to the output of the amplifier 161 via the resistor R2. The signal SS1Gout is input to the non-inverting input terminal of the amplifier 162. The inverting input terminal of the amplifier 162 is connected to the output of the amplifier 162 via the resistor R3.

  The output of the amplifier 161 is connected to the non-inverting input terminal of the amplifier 163 via the resistor R4. The output of the amplifier 162 is connected to the inverting input terminal of the amplifier 163 via the resistor R5. The inverting input terminal of the amplifier 163 is connected to the output of the amplifier 163. The output of the amplifier 163 is output as the output signal Vout of the instrumentation amplifier unit 160.

  In this embodiment, the noise on the signal line SSG1 side (GND side) is removed in the buffer unit 120 in this way, and the noise of the detection signal SS1out is reduced by passing through the instrumentation amplifier 160, and output as the output signal Vout. can do.

  Therefore, in this embodiment, the S / N ratio of the detection signal output according to the displacement of the piezoelectric actuator can be improved. That is, in this embodiment, the S / N ratio of the detection signal can be increased.

  The piezoelectric actuator drive system 100 of the present embodiment may be mounted on a video device that scans light and displays an image, such as a projector.

(Second embodiment)
A second embodiment of the present invention will be described below with reference to the drawings. The second embodiment of the present invention is different from the first embodiment only in that the buffer unit is provided in the MEMS unit. Therefore, in the following description of the second embodiment, only differences from the first embodiment will be described, and those having the same functional configuration as the first embodiment will be used in the description of the first embodiment. The description is omitted.

  FIG. 14 shows an example of a MEMS unit having a buffer unit.

  The MEMS unit 110 </ b> A of this embodiment includes a piezoelectric actuator 200 and a buffer unit 120.

  In the MEMS unit 110A of this embodiment, in addition to the signal lines output from the conventional MEMS unit 1 shown in FIG. That is, in this embodiment, the S / N ratio of the detection signal can be improved by simply adding the buffer unit 120 and the four power supply lines to the conventional MEMS unit 1. That is, in this embodiment, the S / N ratio of the detection signal can be increased.

  As mentioned above, although this invention has been demonstrated based on each embodiment, this invention is not limited to the requirements shown in the said embodiment. With respect to these points, the gist of the present invention can be changed without departing from the scope of the present invention, and can be appropriately determined according to the application form.

DESCRIPTION OF SYMBOLS 100 Piezoelectric actuator drive system 110 MEMS unit 120 Buffer part 140 Board | substrate 160 Instrumentation amplifier 170 Drive part 200 Piezoelectric actuator

JP 2007-226108 A JP 2011-4339 A

Claims (6)

A piezoelectric actuator drive system having a piezoelectric actuator and a substrate connected to the piezoelectric actuator,
A piezoelectric actuator drive system including a buffer unit that is disposed in the vicinity of the piezoelectric actuator and that receives a detection signal output from the piezoelectric actuator in accordance with the operation of the piezoelectric actuator.   The piezoelectric actuator drive system according to claim 1, wherein an output of the buffer unit is connected to an amplifier unit provided on the substrate. The piezoelectric actuator is
An operation detecting means for outputting the detection signal corresponding to the operation of the piezoelectric actuator;
The buffer unit is
A current-voltage converter that converts the detection signal output from the operation detection means from current to voltage;
The piezoelectric actuator drive system according to claim 1, further comprising: a voltage buffer unit connected to a reference potential.   The piezoelectric actuator drive system according to claim 1, wherein the amplifier unit is an instrumentation amplifier.   The piezoelectric actuator drive system according to any one of claims 1 to 4, wherein the buffer unit and the piezoelectric actuator are built in a MEMS unit. A video actuator that has a piezoelectric actuator that swings a mirror and a substrate connected to the piezoelectric actuator, and that scans the light applied to the mirror to display an image;
The video equipment which has the buffer part which is arrange | positioned in the vicinity of the said piezoelectric actuator and into which the detection signal output from the said piezoelectric actuator according to operation | movement of the said piezoelectric actuator is input.