JP6515723B2 - Rotary actuator - Google Patents

Description

  The present invention relates to a rotary actuator.

  In recent years, rotary actuators have been developed. The rotary actuator is used, for example, in a light scanner. Patent Documents 1 to 3 describe an example of a rotary actuator. In this example, the rotary actuator comprises a movable electrode, a fixed electrode, and a detection electrode. The movable electrode is rotated by the voltage between the movable electrode and the fixed electrode. The rotation of the movable electrode is detected by the capacitance between the movable electrode and the detection electrode.

JP, 2005-208251, A JP, 2014-21188, A JP, 2014-21189, A

  As described above, in the rotary actuator, the movable electrode is rotated by the electrical signal input to the fixed electrode. The rotation of the movable electrode is detected by the capacitance between the movable electrode and the detection electrode, that is, the electric signal output from the detection electrode. In the application of the rotary actuator, an electrical signal synchronized with the electrical signal output from the detection electrode may be generated. In this case, the difference between the phase of the electrical signal output from the detection electrode and the phase of the electrical signal synchronized with the electrical signal output from the detection electrode is the condition of the electrical signal input to the fixed electrode (for example, the frequency It is important to make it constant regardless of).

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to generate an electrical signal synchronized with an electrical signal output from a detection electrode in a rotary actuator. The purpose of the present invention is to make the phase difference between the phase of the electrical signal and the phase of the electrical signal synchronized with the electrical signal output from the detection electrode constant regardless of the condition of the electrical signal input to the fixed electrode.

  The rotary actuator according to the present invention comprises an actuator body and a circuit. The actuator body includes a movable electrode, a shaft member, a fixed electrode, and a detection electrode. The shaft member serves as the rotation axis of the movable electrode. The fixed electrode faces the movable electrode in plan view. The detection electrode faces the movable electrode in plan view. The circuit includes a signal output unit, a phase control unit, and a first multiplier. The signal output unit outputs the drive electrode to the fixed electrode. The phase control unit controls the phase of the adjustment signal extracted from the drive signal. The first multiplier multiplies the electrical signal from the phase control unit and the electrical signal from the detection electrode. The phase control unit controls the phase of the adjustment signal based on time integration of the electric signal output from the first multiplier.

  A rotary actuator according to the present invention includes the above-described actuator body, and further includes a circuit. The circuit includes a signal output unit, a phase control unit, and a first multiplier. The signal output unit outputs a drive signal. The phase control unit controls the phase of the drive signal and outputs an electrical signal to the fixed electrode. The first multiplier multiplies the adjustment signal extracted from the drive signal by the electrical signal from the detection electrode. The phase control unit controls the phase of the drive signal based on the time integration of the electrical signal from the first multiplier.

  According to the present invention, when the rotary actuator generates an electrical signal synchronized with the electrical signal output from the detection electrode, the phase of the electrical signal output from the detection electrode and the electrical signal output from the detection electrode It is possible to make the phase shift of the electrical signal synchronized with the signal be constant regardless of the condition of the electrical signal input to the fixed electrode.

It is a figure which shows the structure of the actuator main body used for the rotary actuator (FIG. 2) which concerns on 1st Embodiment. It is a figure showing composition of a rotary type actuator concerning a 1st embodiment. (A) is a figure for demonstrating the voltage V1 and the voltage V2, (b) is a figure for demonstrating the voltage V3. (A) is a figure for demonstrating the relationship of the voltage V1 and the voltage V4, (b) is a figure for demonstrating the relationship of the voltage V5 and the voltage V4. It is a figure which shows the modification of FIG. It is a figure which shows the detail of a structure of the analog multiplier shown in FIG. It is a figure showing composition of a rotation type actuator concerning a 2nd embodiment. (A) is a figure which shows the relationship between the voltage V4 and the voltage V82, (b) is a figure which shows the relationship between the voltage V4 and the voltage V84. It is a figure showing composition of a rotary type actuator concerning a 3rd embodiment. (A) is a figure which shows the relationship between the voltage V4 and the voltage V86, (b) is a figure which shows the relationship between the voltage V4 and the voltage V88. It is a figure which shows the structure of the rotary actuator which concerns on 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

First Embodiment
FIG. 1 is a view showing the configuration of an actuator main body 100 used in a rotary actuator (FIG. 2) according to the first embodiment. The actuator main body 100 includes a frame 110, a movable electrode 120, a holding member 130, a fixed electrode 140, and a detection electrode 150. In the example shown in the figure, the control unit 300 is provided outside the actuator body 100. The holding member 130 (shaft member) attaches the movable electrode 120 to the frame 110, and serves as a rotation axis of the movable electrode 120. The fixed electrode 140 faces the movable electrode 120 in plan view. The detection electrode 150 is aligned with the fixed electrode 140 and faces the side of the movable electrode 120 facing the fixed electrode 140.

  The planar shape of the movable electrode 120 is rectangular. And two fixed electrodes 140 are provided so as to sandwich the movable electrode 120 in a plan view. The side (the side extending in the X direction in FIG. 1) of the movable electrode 120 facing the fixed electrode 140 has a comb shape. The frame 110 is opposed to two of the four sides of the movable electrode 120 which are not opposed to the fixed electrode 140 (sides extending in the Y direction in FIG. 1). The holding member 130 is provided for each of two sides of the movable electrode 120 facing the frame 110. Specifically, the holding member 130 is connected to the center of the side of the movable electrode 120 facing the frame 110. The line connecting the two holding members 130 is the rotation axis of the movable electrode 120. In the present embodiment, the frame 110, the movable electrode 120, and the holding member 130 are integrally formed.

  The side of the fixed electrode 140 facing the movable electrode 120 has a comb-like shape, and is engaged with the comb-tooth portion of the movable electrode 120. For this reason, the area of the part which the fixed electrode 140 and the movable electrode 120 mutually oppose becomes large, As a result, the driving force of the movable electrode 120 becomes large.

  The upper surface of the movable electrode 120 of the actuator body 100 is, for example, a mirror surface. The mirror surface is formed, for example, by forming a metal film (for example, an Al film) on the upper surface of the movable electrode 120. Then, by changing the angle of the movable electrode 120, the reflection angle of the light incident on the movable electrode 120 is changed. The actuator body 100 is used, for example, for a light scanner or a motion sensor.

  The detection electrode 150 is aligned with the fixed electrode 140 and faces the side of the movable electrode 120 facing the fixed electrode 140. In the example shown in the figure, the fixed electrode 140 is opposed to the central portion of the side of the movable electrode 120. The detection electrode 150 is provided to sandwich the fixed electrode 140, and is opposed to both ends of the side of the movable electrode 120. The fixed electrode 140 is larger than the detection electrode 150. In the example shown in the figure, the detection electrodes 150 are provided on two opposing sides of the movable electrode 120. That is, the detection electrodes 150 are provided so as to be line symmetrical with respect to the holding member 130. However, the detection electrode 150 may be provided only on one side of the movable electrode 120.

  When the movable electrode 120 rotates, the capacitance generated between the movable electrode 120 and the detection electrode 150 changes. Therefore, the control unit 300 can calculate the rotation angle of the movable electrode 120 based on the magnitude of the capacitance. That is, the control unit 300 detects the capacitance between the movable electrode 120 and the detection electrode 150, and controls the DC voltage based on the magnitude of the detected capacitance. Thereby, the control unit 300 can control the rotation angle of the movable electrode 120 to a desired value.

  FIG. 2 is a view showing the configuration of the rotary actuator according to the present embodiment. FIG. 1 corresponds to a view showing the configuration of the actuator main body 100 shown in FIG. The rotary actuator comprises an actuator body 100 and a circuit 200. In the example shown in the figure, the control unit 300 is a computer, more specifically, for example, a desktop computer or a laptop computer. The control unit 300 is provided outside the rotary actuator (the actuator body 100 and the circuit 200). The circuit 200 includes a voltage conversion unit 210, a signal amplification unit 220, a phase control unit 230, an XOR gate 240, and a low pass filter 250. The control unit 300 includes a clock generation unit 310.

  The clock generation unit 310 generates a clock. The clock generation unit 310 is, for example, a clock of a central processing unit (CPU). The clock generation unit 310 outputs a clock to the outside of the control unit 300. In the example shown in the figure, the clock is a square wave of a fixed frequency.

  The clock from the clock generation unit 310 is input to the voltage conversion unit 210 (signal output unit). The voltage conversion unit 210 converts the voltage of the clock from the clock generation unit 310 into a predetermined voltage. In this case, the voltage conversion unit 210 does not change the frequency and phase of the clock from the clock generation unit 310. Thus, the voltage conversion unit 210 generates a drive signal.

  The drive signal from the voltage conversion unit 210 is output to the fixed electrode 140 via the signal amplification unit 220. In detail, the signal amplification unit 220 includes a capacitor C22, resistors R22, R24, R26, and an amplifier A1. The capacitor C22, the resistor R22, the resistor R24, and the resistor R26 are connected in series in this order from the voltage conversion unit 210 toward the ground. The capacitor C22 is provided to remove the DC component of the drive signal from the voltage conversion unit 210. The resistors R22, R24, and R26 are provided to divide the voltage of the drive signal from the voltage conversion unit 210. In the example shown in the figure, the amplifier A1 can be electrically connected at any position from between the resistor R22 and the resistor R24 to between the resistor R24 and the resistor R26. As a result, the input voltage of the amplifier A1 is variable from the voltage between the resistors R22 and R24 to the voltage between the resistors R24 and R26. The drive signal amplified by the amplifier A1 is input to the fixed electrode 140 of the actuator body 100.

  The movable electrode 120 of the actuator body 100 vibrates by the voltage applied to the fixed electrode 140. Therefore, the period of the vibration of the movable electrode 120 is the same as the period of the voltage applied to the fixed electrode 140 (that is, the period of the drive signal output from the voltage conversion unit 210). As described above, when the fixed electrode 140 vibrates, the capacitance between the fixed electrode 140 and the detection electrode 150 changes. The period of the change (vibration) of the capacitance is the same as the period of the voltage applied to the fixed electrode 140 (that is, the period of the drive signal output from the voltage conversion unit 210). The change in capacitance (vibration) is detected by the voltage of the detection electrode 150. In the example shown in the figure, the voltage of the detection electrode 150 is amplified by the amplifier A2. In this case, the cycle of the electrical signal output from the amplifier A2 is the same as the cycle of the drive signal output from the voltage conversion unit 210.

  The inventor examined the timing when the electric signal output from the amplifier A2 takes the maximum value or the minimum value, and the electric signal output from the voltage conversion unit 210 transitions from one of the low level signal and the high level signal to the other. It has become clear that the difference between the timings to be performed may change depending on the period of the drive signal from the voltage conversion unit 210. As described in detail below, the circuit 200 outputs a rectangular wave electrical signal from the phase control unit 230. In the example shown in the figure, the timing at which the electric signal output from the phase control unit 230 transitions from one of the low level signal and the high level signal to the other and the electric signal output from the voltage conversion unit 210 is a maximum value or a minimum value. The difference from the timing of taking a value can be made constant regardless of the period of the drive signal from the voltage conversion unit 210.

  The phase control unit 230 is electrically connected between the voltage conversion unit 210 and the signal amplification unit 220. Thereby, the adjustment signal extracted from the drive signal (the electric signal output from the voltage conversion unit 210) is input to the phase control unit 230. The phase control unit 230 controls the phase of the adjustment signal. As described in detail later, the phase control unit 230 controls the phase of the adjustment signal based on the electrical signal from the low pass filter 250. The electrical signal output from the phase control unit 230 may be distorted. Therefore, in the example shown in the drawing, this distortion is removed by the comparator U1, as described later.

  The electrical signal from the phase control unit 230 is input to the XOR gate 240 (first multiplier) via the comparator U1. The electrical signal from the detection electrode 150 (amplifier A2) is input to the XOR gate 240 via the comparator U2. Thereby, the electric signal from the phase control unit 230 and the electric signal from the detection electrode 150 are multiplied by the XOR gate 240. Specifically, XOR gate 240 outputs a low level signal when the electric signal level from phase control unit 230 and the electric signal level from detection electrode 150 are the same, and the electric signal from phase control unit 230 When the level and the electrical signal level from the detection electrode 150 are different from each other, a high level signal is output.

  The comparator U1 compares the potential of the electrical signal from the phase control unit 230 with a reference potential (for example, the ground potential), and outputs a high level signal or a low level signal based on the comparison result. For example, the comparator U1 outputs a high level signal when the potential of the electrical signal from the phase control unit 230 is higher than the ground potential, and the potential of the electrical signal from the phase control unit 230 is lower than the ground potential. Outputs a low level signal. As a result, even if the electrical signal output from the phase control unit 230 is distorted as described above, this distortion can be removed.

  The comparator U2 compares the potential of the electric signal from the amplifier A2 with a reference potential (for example, the ground potential), and outputs a high level signal or a low level signal based on the comparison result. For example, comparator U2 outputs a high level signal when the potential of the electrical signal from amplifier A2 is higher than the ground potential, and low when the potential of the electrical signal from amplifier A2 time integration is lower than the ground potential. Output level signal. Thereby, the electric signal from the amplifier A2 (the electric signal output from the amplifier A2 is a curved wave) can be converted into a rectangular wave.

  In the example shown in the figure, the amplitude of the rectangular wave output from the comparator U1 and the amplitude of the rectangular wave output from the comparator U2 are equal to each other.

  The electrical signal from XOR gate 240 passes through low pass filter 250. The low pass filter 250 is an integrator. Thereby, the low pass filter 250 outputs the time integration of the electric signal from the XOR gate 240.

  The electrical signal from the low pass filter 250 is input to the phase control unit 230 via the comparator U3 (details of the comparator U3 will be described later). As described in detail later, the phase control unit 230 controls the phase of the adjustment signal (the electric signal extracted from the drive signal from the voltage conversion unit 210) based on the electric signal from the low pass filter 250.

  FIG. 3 (a) is a diagram for explaining the voltage V1 and the voltage V2, and FIG. 3 (b) is a diagram for explaining the voltage V3. As shown in FIG. 2, voltage V1 is a voltage between comparator U1 and XOR gate 240, voltage V2 is a voltage between comparator U2 and XOR gate 240, and voltage V3 is XOR gate 240 and low pass filter 250. Voltage between As shown in FIG. 3, the voltage V3 is a low level signal when the level of the electric signal of the voltage V1 and the level of the electric signal of the voltage V2 are the same, and the level of the electric signal of the voltage V1 and the electric signal of the voltage V2 When the level of the signal is different from each other, it becomes a high level signal.

  The function of the phase control unit 230 will be described using FIGS. 2 and 3. As described above, the phase control unit 230 controls the phase of the adjustment signal (a signal extracted from the drive signal from the voltage conversion unit 210) based on the electrical signal from the low pass filter 250. Specifically, the phase control unit 230 controls the phase of the adjustment signal so that the electric signal from the low pass filter 250 has a certain value. In the example shown in the figure, the phase control unit 230 controls the phase of the adjustment signal so that the electrical signal from the low pass filter 250 is substantially zero.

  The difference between the phase of the electric signal (voltage V1) from the phase control unit 230 and the phase of the electric signal (voltage V2) from the detection electrode 150 is the case where the electric signal from the low-pass filter 250 has a certain value. Is fixed. In other words, the phase control unit 230 controls the phase of the adjustment signal so that the electric signal from the low pass filter 250 has a desired value (for example, zero). In the example shown in the figure, the difference between the phase of the electric signal (voltage V1) from the phase control unit 230 and the phase of the electric signal (voltage V2) from the detection electrode 150 is that the signal of voltage V2 is a high level signal. Time integration (+ A) of high level signal of voltage V3 in a certain case, time integration (-A) of low level signal of voltage V3 when signal of voltage V2 is high level signal, signal of voltage V2 is low level signal So that the sum of the time integral (+ B) of the high level signal of voltage V3 and the time integral (−B) of the low level signal of voltage V3 when the signal of voltage V2 is a low level signal is zero It is fixed to

  Even when the phase control unit 230 controls the phase of the adjustment signal so that the electric signal from the low pass filter 250 becomes zero, the electric signal from the low pass filter 250 may deviate from zero. In the example shown in the figure, by using the comparator U3 (first comparator), the electric signal input from the low pass filter 250 to the phase control unit 230 is made substantially zero.

  In detail, the low pass filter 250 is electrically connected to the first input terminal (one of the inverting input terminal and the non-inverting input terminal) of the comparator U3. The adjustment circuit 260, the resistors R52, R54, R56 and the capacitors C52, C54 are electrically connected to the second input terminal (the other of the inverting input terminal and the non-inverting input terminal) of the comparator U3.

  The adjustment circuit 260 includes a variable resistor VR, resistors R62 and R64, and a capacitor C62. A predetermined voltage is applied to both ends of the variable resistor VR. The resistor R62 and the capacitor C62 form a low pass filter. A voltage is applied to the resistor R62 from the variable resistor VR. The capacitor C62 is grounded. A resistor R64 is electrically connected between the resistor R62 and the capacitor C62. Thereby, current flows in the direction from the resistor R62 to the resistor R64. Then, this current is output from the adjustment circuit 260. In this case, the voltage applied to the resistor R62 can be adjusted by adjusting the resistance value of the variable resistor VR. In other words, by adjusting the resistance value of the variable resistor VR, the value of the current output from the adjustment circuit 260 can be adjusted.

  An adjustment reference potential can be applied to the aforementioned second input terminal of the comparator U3. Specifically, the resistor R52 and the capacitor C52 form a low pass filter. The resistor R52 is electrically connected to the above-described second input terminal of the comparator U3. The capacitor C52 is grounded. One end of the resistor R54 is electrically connected between the resistor R52 and the capacitor C52, and the other end of the resistor R54 is grounded. The current from the adjustment circuit 260 flows to the resistor R52. Thus, the adjustment reference potential can be applied to the above-described second input terminal of the comparator U3. As described above, the value of the current from the adjustment circuit 260 can be adjusted by adjusting the resistance value of the variable resistor VR. Therefore, the adjustment reference potential described above can be adjusted by adjusting the resistance value of the variable resistor VR.

  In the example shown in the figure, the output signal from the comparator U3 is fed back to the above-described second input terminal of the comparator U3 via the resistor R56 and the capacitor C54. In this case, the output signal from the comparator U3 is blocked by the low pass filter of the resistor R64 and the capacitor C62, and blocked by the low pass filter of the resistor R52 and the capacitor C52. Therefore, the flow of the output signal from the comparator U3 to the adjustment circuit 260 and the resistor R52 is suppressed. Further, the current from the adjustment circuit 260 is interrupted by the capacitor C54. Therefore, the current from the adjustment circuit 260 is suppressed from flowing to the output terminal of the comparator U3.

  In the example shown in the figure, even if the electric signal from the low pass filter 250 deviates from zero, it is input from the low pass filter 250 to the phase control unit 230 by adjusting the above-mentioned adjustment reference potential of the comparator U3. The electrical signal (that is, the electrical signal input from the comparator U3 to the phase control unit 230) can be made substantially zero.

  FIG. 4A is a view for explaining the relationship between the voltage V1 and the voltage V4, and FIG. 4B is a view for explaining the relationship between the voltage V5 and the voltage V4. As shown in FIG. 2, voltage V1 is a voltage between comparator U1 and XOR gate 240, voltage V4 is a voltage between amplifier A2 and comparator U2, and voltage V5 is output from first divider 272 Voltage of the electrical signal

  The first frequency divider 272 and the second frequency divider 274 will be described with reference to FIGS. 2 and 4. The electrical signal from the phase control unit 230 is input to the first frequency divider 272 and the second frequency divider 274 via the comparator U1. The first frequency divider 272 and the second frequency divider 274 output an electrical signal to the outside of the circuit 200 (the control unit 300 in the example shown in the figure).

  The first frequency divider 272 and the second frequency divider 274 are both provided to divide the frequency of the electric signal from the comparator U1 into 1/2. More specifically, at the timing when the electric signal (voltage V1) from the comparator U1 transitions from the high level signal to the low level signal, the first frequency divider 272 holds the low level signal, and the high level signal Output a low level signal when holding a high level signal (for example, FIG. 4 (b)). On the other hand, at the timing when the electric signal (voltage V1) from the comparator U1 transitions from the low level signal to the high level signal, the second frequency divider 274 holds the low level signal, and the high level signal Output a low level signal when holding a high level signal. The first frequency divider 272 and the second frequency divider 274 are formed using, for example, flip-flops.

  FIG. 5 is a view showing a modification of FIG. In the example shown in the figure, the XOR gate 240 (FIG. 2) is replaced with the analog multiplier 242 (first multiplier). Furthermore, the electrical signal from the detection electrode 150 (amplifier A2) is directly input to the analog multiplier 242 without passing through the comparator U2 (FIG. 2). Also in the example shown in the figure, the difference between the phase of the electric signal from the phase control unit 230 and the phase of the electric signal from the detection electrode 150 can be fixed.

  FIG. 6 is a diagram showing details of the configuration of the analog multiplier 242 shown in FIG. In the example shown in the figure, the analog multiplier 242 calculates the product of the electric signal from the comparator U1 (phase control unit 230) and the electric signal from the amplifier A2 (detection electrode 150), and the low pass filter Output to 250.

  In detail, the analog multiplier 242 includes an operational amplifier O42 and switches S42, S44, S46, and S48. The switches S42, S44, S46, and S48 all open when a high level signal is input and close when a low level signal is input. The switches S42 and S46 are electrically connected to the inverting input terminal (-) of the operational amplifier O42, and the switches S44 and S48 are electrically connected to the non-inverting input terminal (+) of the operational amplifier O42. In the example shown in the figure, the comparators U1 (phase control unit 230) are electrically connected to the switches S42 and S48 via the NOT gates N42 and N44 connected in series, and the switches S44 and S46 are not connected. The amplifier A2 (detection electrode 150) is electrically connected through the gate N46. In the example shown in the figure, a high level signal is input from the comparator U1 (phase control unit 230) to the analog multiplier 242. In this case, the switches S42 and S48 open and the switches S44 and S46 close.

  In the example shown in the figure, the resistors R41 and R43 and the capacitor C42 are electrically connected to the inverting input terminal (-) of the operational amplifier O42. The resistor R41, the switch S42, and the capacitor C42 are connected in series in this order from the amplifier A2 (detection electrode 150) to the ground. Thus, when the switch S42 is closed, the resistor R41 and the capacitor C42 form a low pass filter. Further, from the point between the switch S42 and the capacitor C42 to the ground, the switch S46 and the resistor R43 are connected in series in this order.

  Similarly, the resistors R42 and R44 and the capacitor C44 are electrically connected to the noninverting input terminal (+) of the operational amplifier O42. The resistor R42, the switch S44, and the capacitor C44 are connected in series in this order from the amplifier A2 (detection electrode 150) to the ground. Thus, when the switch S44 is closed, the resistor R42 and the capacitor C44 form a low pass filter. Further, from between the switch S44 and the capacitor C44 to the ground, the switch S48 and the resistor R44 are connected in series in this order.

  A resistor R45 is electrically connected to the inverting input terminal (-) of the operational amplifier O42. The resistor R45 electrically connects the inverting input terminal (-) of the operational amplifier O42 between the switch S42 and the capacitor C42. A resistor R47 and a capacitor C46 are provided in parallel between the output terminal of the operational amplifier O42 and the inverting input terminal (-) of the operational amplifier O42. When an electrical signal is input to the non-inverting input terminal (+) of the operational amplifier O42, the operational amplifier O42, the resistors R45 and R47, and the capacitor C46 function as an integrating circuit (low pass filter).

  Resistors R46 and R48 and a capacitor C48 are electrically connected to the noninverting input terminal (+) of the operational amplifier O42. The resistor R46 and the capacitor C48 are connected in series in this order in the direction from between the switch S44 and the capacitor C44 to the ground. Thus, when the switch S44 is closed, the resistor R46 and the capacitor C48 become a low pass filter. The resistor R48 connects between the resistor R46 and the capacitor C48 to the ground.

  When a high level signal is input from the operational amplifier O42 (phase control unit 230) to the analog multiplier 242, the switches S42 and S48 open and the switches S44 and S46 close. In this case, the electric signal from the amplifier A2 (detection electrode 150) is non-inverted and amplified by the operational amplifier O42. On the other hand, when a low level signal is input from the comparator U1 (phase control unit 230) to the analog multiplier 242, the switches S44 and S46 open and the switches S42 and S48 close. In this case, the electric signal from the amplifier A2 (detection electrode 150) is inverted and amplified by the operational amplifier O42. Thus, the analog multiplier 242 multiplies the electric signal from the comparator U1 (phase control unit 230) and the electric signal from the amplifier A2 (detection electrode 150).

  As described above, according to the present embodiment, the adjustment signal extracted from the drive signal output from the voltage conversion unit 210 is input to the phase control unit 230. The phase control unit 230 controls the phase of the adjustment signal based on the electrical signal from the low pass filter 250. Thus, the shift between the phase of the electric signal output from the phase control unit 230 and the phase of the electric signal output from the detection electrode 150 can be made constant regardless of the frequency of the drive signal.

Second Embodiment
FIG. 7 is a view showing a configuration of a rotary actuator according to a second embodiment, which corresponds to FIG. 2 of the first embodiment. The rotary actuator according to this embodiment has the same configuration as the rotary actuator according to the first embodiment except for the following points.

  In the example shown in the figure, the circuit 200 of the rotary actuator includes a determination circuit 280. Determination circuit 280 includes a NOT gate N82, analog multipliers M82 and M84, low pass filters L82 and L84, and a comparator U82. As shown in the figure, the electric signal from the first frequency divider 272 is input to the analog multiplier M82 (second multiplier), and the electric signal from between the amplifier A2 and the comparator U2 is the analog multiplier M82. (The second multiplier). Furthermore, the electric signal from the first frequency divider 272 is input to the analog multiplier M84 (third multiplier) via the NOT gate N82, and the electric signal from between the amplifier A2 and the comparator U2 is an analog multiplier. M84 (third multiplier) is input. The electrical signal from the analog multiplier M82 is input to the comparator U82 (second comparator) via the low pass filter L82. The electrical signal from the analog multiplier M84 is input to the comparator U82 (second comparator) via the low pass filter L84.

  As described above, the electrical signal output from the first frequency divider 272 is a rectangular wave that transitions from one of the high level signal and the low level signal to the other at the timing when the electrical signal from the amplifier A2 has a local minimum value. . In other words, the electric signal (rectangular wave) output from the first frequency divider 272 becomes either the high level signal or the low level signal at the timing when the electric signal from the amplifier A2 has the maximum value. As described later with reference to FIG. 8, depending on the state of the actuator main body 100, the electric signal from the amplifier A2 alternately repeats the first maximum value and the second maximum value which are different from each other. In this case, in the example shown in the figure, by using the determination circuit 280, it can be determined in which direction the movable electrode 120 (FIG. 1) is rotating.

  FIG. 8 (a) is a diagram showing the relationship between the voltage V4 and the voltage V82, and FIG. 8 (b) is a diagram showing the relationship between the voltage V4 and the voltage V84. As shown in FIG. 7, voltage V4 is a voltage between amplifier A2 and comparator U2, V82 is a voltage between first frequency divider 272 and analog multiplier M82, and V84 is an analog of NOT gate N82 and an analog It is a voltage between the multipliers M84. As shown in FIG. 8, the electric signal (voltage V4) from the amplifier A2 has alternately repeated first maximum values and second maximum values which are different from each other.

  A method of determining in which direction the movable electrode 120 (FIG. 1) is rotated will be described with reference to FIGS. 7 and 8. The analog multiplier M82 multiplies the voltage V4 by the voltage V82, and the analog multiplier M84 multiplies the voltage V4 by the voltage V84. The low-pass filter L82 calculates the time integration of the electrical signal from the analog multiplier M82, and the low-pass filter L84 calculates the time integration of the electrical signal from the analog multiplier M84.

  In the example shown in FIG. 8, the time integration (corresponding to FIG. 8 (a)) from the low pass filter L82 is larger than the time integration (corresponding to FIG. 8 (b)) from the low pass filter L84. This is because, in the example shown in FIG. 8A, the voltage V4 takes a large maximum value between the first maximum value and the second maximum value at the timing when the voltage V82 is a high level signal. In the example shown in b), the voltage V4 takes a smaller maximum value between the first maximum value and the second maximum value at the timing when the voltage V84 is a high level signal.

  The electrical signal from the low pass filter L82 and the electrical signal from the low pass filter L84 are input to the comparator U82. Comparator U82 compares the magnitude of the electrical signal from low pass filter L82 with the magnitude of the electrical signal from low pass filter L84. Then, the comparator U82 outputs the high level signal or the low level signal to the control unit 300 based on the comparison result. For example, the comparator U82 outputs a low level signal when the electric signal from the low pass filter L82 is larger than the electric signal from the low pass filter L84, and the electric signal from the low pass filter L82 is higher than the electric signal from the low pass filter L84. If it is too small, it outputs a high level signal.

  The control unit 300 includes a storage unit 320 and a determination unit 330. Storage unit 320 calculates the direction in which movable electrode 120 (FIG. 1) is rotated, and the difference between the electrical signal from low pass filter L82 and the electrical signal from low pass filter L84 (ie, the output signal from comparator U82). I remember the relationship between The determination unit 330 reads the above-described relationship from the storage unit 320. Further, determination unit 330 receives an output signal from comparator U82. Thereby, the determination unit 330 can determine the direction in which the movable electrode 120 (FIG. 1) is rotating based on the above-described relationship and the output signal from the comparator U82.

Third Embodiment
FIG. 9 is a view showing a configuration of a rotary actuator according to a third embodiment, which corresponds to FIG. 7 of the second embodiment. The rotary actuator according to the present embodiment has the same configuration as the rotary actuator according to the second embodiment except for the following points.

  In the example shown in the drawing, the determination circuit 280 includes a NOT gate N82, S / H circuits (sample and hold circuits) SH82 and SH84, low pass filters L82 and L84, and a comparator U82. As shown in the figure, the electric signal from the second frequency divider 274 is input to the S / H circuit SH82, and the electric signal from between the amplifier A2 and the comparator U2 is input to the S / H circuit SH82. . Further, the electric signal from the second frequency divider 274 is input to the S / H circuit SH84 through the NOT gate N82, and the electric signal from between the amplifier A2 and the comparator U2 is input to the S / H circuit SH84. Ru. The electrical signal from the S / H circuit SH82 is input to the comparator U82 (second comparator) via the low pass filter L82. The electrical signal from the S / H circuit SH84 is input to the comparator U82 (second comparator) via the low pass filter L84.

  As described above, the electric signal output from the second frequency divider 274 is a rectangular wave that transitions from one of the high level signal to the other at the low level signal at the timing when the electric signal from the amplifier A2 has a maximum value. . As described later with reference to FIG. 10, depending on the state of the actuator body 100, the electric signal from the amplifier A2 alternately repeats the first maximum value and the second maximum value which are different from each other. In this case, in the example shown in the figure, by using the determination circuit 280, it can be determined in which direction the movable electrode 120 (FIG. 1) is rotating.

  FIG. 10A shows the relationship between the voltage V4 and the voltage V86, and FIG. 10B shows the relationship between the voltage V4 and the voltage V88. As shown in FIG. 9, voltage V4 is a voltage between amplifier A2 and comparator U2, V86 is a voltage between second frequency divider 274 and S / H circuit SH82, and V88 is NOT gate N82 and It is a voltage between the S / H circuit SH84. As shown in FIG. 10, the electric signal (voltage V4) from the amplifier A2 has alternately repeated first maximum values and second maximum values which are different from each other.

  A method of determining in which direction the movable electrode 120 (FIG. 1) is rotated will be described with reference to FIGS. 9 and 10. The S / H circuit SH82 outputs the same electrical signal as the voltage V4 when the voltage V86 is a high level signal (sample mode), and the voltage V86 is high when the voltage V86 is a low level signal. The voltage V4 (that is, the maximum value of the electric signal of the voltage V4) at the timing of transition from the level signal to the low level signal is output (hold mode). The S / H circuit SH84 outputs the same electrical signal as the voltage V4 when the voltage V88 is a high level signal (sample mode), and the voltage V88 is high when the voltage V88 is a low level signal. The voltage V4 (that is, the maximum value of the electric signal of the voltage V4) at the timing of transition from the level signal to the low level signal is output (hold mode). The low-pass filter L82 calculates the time integration of the electric signal from the S / H circuit SH82, and the low-pass filter L84 calculates the time integration of the electric signal from the S / H circuit SH84.

  In the example shown in FIG. 10, the time integration (corresponding to FIG. 10 (a)) from the low pass filter L82 is larger than the time integration (corresponding to FIG. 10 (b)) from the low pass filter L84. This is because the electric signal (corresponding to FIG. 10A) output by the S / H circuit SH82 in the hold mode is different from the electric signal output (corresponding to FIG. 10B) the S / H circuit SH84 outputs in the hold mode. Is also large. The reason why such a difference occurs is that, as described above, in the electric signal of the voltage V4, the first maximum value and the second maximum value which are different from each other are alternately repeated.

  The electrical signal from the low pass filter L82 and the electrical signal from the low pass filter L84 are input to the comparator U82. Comparator U82 compares the magnitude of the electrical signal from low pass filter L82 with the magnitude of the electrical signal from low pass filter L84. Then, the comparator U82 outputs the high level signal or the low level signal to the control unit 300 based on the comparison result. For example, the comparator U82 outputs a low level signal when the electric signal from the low pass filter L82 is larger than the electric signal from the low pass filter L84, and the electric signal from the low pass filter L82 is higher than the electric signal from the low pass filter L84. If it is too small, it outputs a high level signal.

  The control unit 300 includes a storage unit 320 and a determination unit 330. Storage unit 320 calculates the direction in which movable electrode 120 (FIG. 1) is rotated, and the difference between the electrical signal from low pass filter L82 and the electrical signal from low pass filter L84 (ie, the output signal from comparator U82). I remember the relationship between The determination unit 330 reads the above-described relationship from the storage unit 320. Further, determination unit 330 receives an output signal from comparator U82. Thereby, the determination unit 330 can determine the direction in which the movable electrode 120 (FIG. 1) is rotating based on the above-described relationship and the output signal from the comparator U82.

Fourth Embodiment
FIG. 11 is a view showing the configuration of a rotary actuator according to a fourth embodiment, which corresponds to FIG. 2 of the first embodiment. The rotary actuator according to this embodiment has the same configuration as the rotary actuator according to the first embodiment except for the following points.

  The clock generation unit 310 generates a clock. The clock from the clock generation unit 310 is input to the voltage conversion unit 210 (signal output unit). The voltage conversion unit 210 converts the voltage of the clock from the clock generation unit 310 into a predetermined voltage. Thus, the voltage conversion unit 210 generates a drive signal.

  The drive signal from the voltage conversion unit 210 is input to the phase control unit 230. The phase control unit 230 controls the phase of the drive signal. As described in detail later, the phase control unit 230 controls the phase of the drive signal based on the electrical signal from the low pass filter 250.

  The electrical signal output from the phase control unit 230 may be distorted. Therefore, in the example shown in the drawing, this distortion is removed by the comparator U1, as described later.

  The electrical signal from the phase control unit 230 is input to the signal amplification unit 220 via the comparator U1. As described with reference to FIG. 2, the comparator U1 compares the potential of the electric signal from the phase control unit 230 with the reference potential (for example, the ground potential), and based on the comparison result, the high level signal or the low level Output a signal. Thereby, distortion of the electrical signal from the phase control unit 230 can be removed. Furthermore, as described with reference to FIG. 2, the signal amplification unit 220 amplifies the electric signal from the comparator U1 and outputs the amplified electric signal to the fixed electrode 140.

  The movable electrode 120 of the actuator body 100 vibrates by the voltage applied to the fixed electrode 140. When the fixed electrode 140 vibrates, the capacitance between the fixed electrode 140 and the detection electrode 150 changes. The change in capacitance (vibration) is detected by the voltage of the detection electrode 150. In the example shown in the figure, the voltage of the detection electrode 150 is amplified by the amplifier A2.

  An adjustment signal is extracted from the drive signal between the voltage conversion unit 210 and the phase control unit 230. Then, the adjustment signal is input to the XOR gate 240 (multiplier). The electrical signal from the detection electrode 150 (amplifier A2) is input to the XOR gate 240 via the comparator U2. Thereby, the electric signal (adjustment signal) from between the voltage conversion unit 210 and the phase control unit 230 and the electric signal from the detection electrode 150 are multiplied by the XOR gate 240. As in the example shown in FIG. 2, the comparator U2 is provided to convert the electric signal from the amplifier A2 into a rectangular wave.

  The electrical signal from XOR gate 240 passes through low pass filter 250. The low pass filter 250 is an integrator. Thereby, the low pass filter 250 outputs the time integration of the electric signal from the XOR gate 240.

  The electric signal from the low pass filter 250 is input to the phase control unit 230 via the comparator U3 (the function of the comparator U3 is the same as the example shown in FIG. 2). The phase control unit 230 controls the phase of the drive signal based on the electrical signal from the low pass filter 250. Specifically, the phase control unit 230 fixes the difference between the phase of the electrical signal (adjustment signal) from between the voltage conversion unit 210 and the phase control unit 230 and the phase of the electrical signal from the detection electrode 150. The phase of the drive signal is controlled such that the electric signal output from the low pass filter 250 has a certain value (for example, zero).

  A first frequency divider 272 and a second frequency divider 274 are electrically connected between the voltage conversion unit 210 and the XOR gate 240. Similar to the example shown in FIG. 2, the first frequency divider 272 and the second frequency divider 274 receive the electric signal input to the first frequency divider 272 and the electric power input to the second frequency divider 274. It is provided to divide each signal.

  According to the present embodiment, the drive signal output from the voltage conversion unit 210 is input to the phase control unit 230. Further, the adjustment signal extracted from the drive signal is input to the XOR gate 240. The phase control unit 230 controls the phase of the drive signal based on the electrical signal from the XOR gate 240. Thus, the shift between the phase of the electrical signal (drive signal) output from the voltage conversion unit 210 and the phase of the electrical signal output from the detection electrode 150 can be made constant regardless of the frequency of the drive signal. .

  Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than the above can also be adopted.

100 actuator body 110 frame 120 movable electrode 130 holding member 140 fixed electrode 150 detection electrode 200 circuit 210 voltage conversion unit 220 signal amplification unit 230 phase control unit 240 XOR gate 242 analog multiplier 250 low pass filter 260 adjustment circuit 272 first portion Peripheral device 274 Second divider 300 Control unit 310 Clock generation unit A1 Amplifier A2 Amplifier C22 Capacitor C42 Capacitor C44 Capacitor C46 Capacitor C48 Capacitor C52 Capacitor C54 Capacitor C42 Capacitor N42 NOT gate N46 NOT gate O42 Op amp R22 Resistor R24 Resistor R26 Resistor R41 Resistor R42 Resistor R43 Resistor R44 Resistor R45 Resistor R47 Resistor R48 Resistor R52 Resistor R54 Resistor R56 Resistor R62 Resistor R62 Anti-R64 resistance S42 switch S44 switch S46 switch S1 switch U1 comparator U2 comparator U3 comparator V1 voltage V2 voltage V3 voltage V4 voltage V5 voltage V82 voltage V84 voltage V86 voltage V88 voltage VR variable resistor

Claims (5)

An actuator body,
Circuit,
Equipped with
The actuator body is
A movable electrode,
A shaft member serving as a rotation axis of the movable electrode;
A fixed electrode facing the movable electrode in plan view;
A detection electrode facing the movable electrode in plan view;
Equipped with
The circuit is
A signal output unit that outputs a drive signal to the fixed electrode;
A phase control unit that controls the phase of the adjustment signal extracted from the drive signal;
A first multiplier that multiplies the electric signal from the phase control unit and the electric signal from the detection electrode;
Equipped with
The said phase control part controls the phase of the said signal for adjustment based on the time integral of the electric signal output from said 1st multiplier. In the rotary actuator according to claim 1,
The circuit is
A first comparator compares the time integration of the electrical signal output from the first multiplier with the adjustment reference potential, and outputs the electrical signal to the phase control unit.
The rotary actuator wherein the adjustment reference potential is variable. The rotary actuator according to claim 1 or 2
The circuit is
A frequency divider that switches an output signal from one of a high level signal and a low level signal to the other when the electric signal from the phase control unit transitions from a high level signal to a low level signal;
A second multiplier that multiplies the electrical signal from the divider and the electrical signal from the detection electrode;
A third multiplier that multiplies the inverted signal of the electrical signal from the divider and the electrical signal from the detection electrode;
A second comparator that compares the time integral of the electrical signal from the second multiplier with the time integral of the electrical signal from the third multiplier;
Rotary actuator. The rotary actuator according to claim 1 or 2
The circuit is
A frequency divider that switches an output signal from one of a high level signal and a low level signal to the other at a timing when the electric signal from the phase control unit transitions from a low level signal to a high level signal;
A first S / H (sample and hold) circuit that processes the electrical signal from the detection electrode based on the electrical signal from the frequency divider;
A second S / H circuit that processes the electrical signal from the detection electrode based on the inverted signal of the electrical signal from the frequency divider;
A second comparator that compares the time integration of the electrical signal from the first S / H circuit with the time integration of the electrical signal from the second S / H circuit;
Rotary actuator. An actuator body,
Circuit,
Equipped with
The actuator body is
A movable electrode,
A shaft member serving as a rotation axis of the movable electrode;
A fixed electrode facing the movable electrode in plan view;
A detection electrode facing the movable electrode in plan view;
Equipped with
The circuit is
A signal output unit that outputs a drive signal;
A phase control unit that controls the phase of the drive signal and outputs an electrical signal to the fixed electrode;
A first multiplier that multiplies the adjustment signal extracted from the drive signal and the electrical signal from the detection electrode;
Equipped with
The said phase control part controls the phase of the said drive signal based on the time integration of the electric signal from a said 1st multiplier.

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