JP2003204683A - Method of inspecting and adjusting piezoelectric actuator, and inspection device for piezoelectric actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To readily and accurately inspect the vibration of a piezoelectric actuator. <P>SOLUTION: The vibration locus at a piezoelectric actuator in normal action drive of the target of drive (hereinafter, referred to as 'normal vibration locus') is measured in advance. Next, the vibration locus at driving of the piezoelectric actuator, which is the target of inspection driving the target of drive is measured. Then, if this vibration locus lies outside of a certain range centered around the normal vibration locus, the action of the piezoelectric actuator which is the target of inspection is considered defective. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method for inspecting the vibration state of a piezoelectric actuator, an adjusting method for adjusting the vibration state of the piezoelectric actuator according to the inspection result,
And inspection equipment.

[0002]

2. Description of the Related Art Since a piezoelectric element is excellent in conversion efficiency from electric energy to mechanical energy and responsiveness, various piezoelectric actuators utilizing the piezoelectric effect of the piezoelectric element have been developed. As this piezoelectric actuator, generally known is one that vertically vibrates only in the longitudinal direction, but in recent years, a piezoelectric actuator that vibrates by combining this longitudinal vibration and bending vibration in the width direction orthogonal to the longitudinal direction has been proposed. Being developed. This piezoelectric actuator performs vertical vibration and bending vibration when an AC voltage having a frequency intermediate between the natural frequency of longitudinal vibration and the natural frequency of bending vibration is applied. in this way,
In order for the piezoelectric actuator to simultaneously perform longitudinal vibration and bending vibration, it is necessary that the respective natural frequencies be within the standard. Therefore, conventionally, in the manufacturing process of the piezoelectric actuator, each of the natural frequency of the longitudinal vibration and the natural frequency of the bending vibration is measured, and it is determined whether or not each measured value is within the standard. Tests are being conducted to determine whether the piezoelectric actuator will vibrate normally.

[0003]

However, there is a problem that it is technically difficult to measure each of the natural frequency of longitudinal vibration and the natural frequency of bending vibration.
Further, in the conventional inspection, there was a problem that even if each natural frequency of the piezoelectric actuator was within the standard, it was not guaranteed that the piezoelectric actuator would normally vibrate when attached to the device. .

The present invention has been made in view of the above-mentioned circumstances, and a method of inspecting a piezoelectric actuator capable of easily and accurately inspecting the vibration of the piezoelectric actuator, and the vibration of the piezoelectric actuator according to the inspection result. An object of the present invention is to provide a method for adjusting a piezoelectric actuator to be adjusted, and an inspection device for the piezoelectric actuator.

[0005]

In order to achieve the above object, the present invention provides a first process for obtaining a vibration locus as a normal vibration locus when a piezoelectric actuator operating as a non-defective product drives an object by vibration. A second process of acquiring a vibration locus when the piezoelectric actuator to be inspected drives the object by vibration, a normal vibration locus acquired in the first process, and a normal vibration locus acquired in the second process. Provided is a method for inspecting a piezoelectric actuator, which comprises a third step of comparing the vibration locus with each other and setting the operation of the piezoelectric actuator to be inspected as a malfunction when the deviation between the two vibration loci is outside a certain range. .

In order to achieve the above object, the present invention provides a first acquisition means for acquiring a vibration locus as a normal vibration locus when a piezoelectric actuator operating as a non-defective product drives an object by vibration, and an inspection target. Second acquisition means for acquiring a vibration locus when the piezoelectric actuator drives the object by vibration, a normal vibration locus acquired in the first step, and a vibration locus acquired in the second step. And an output unit that outputs information indicating that the operation of the piezoelectric actuator to be inspected is defective when the deviation of the vibration loci of both is out of a certain range. I will provide a.

According to the piezoelectric actuator inspecting method and the piezoelectric actuator inspecting device of the present invention, the vibration locus when the non-defective piezoelectric actuator drives an object by vibration is acquired as a normal vibration locus.
Further, a vibration locus when the piezoelectric actuator to be inspected drives the object by vibration is acquired. Then, the normal vibration locus and the vibration locus of the piezoelectric actuator to be inspected are compared, and when the deviation of the vibration loci of both is out of a certain range, the operation of the piezoelectric actuator to be inspected is malfunctioning. To be done.

Therefore, according to the piezoelectric actuator inspecting method and the piezoelectric actuator inspecting apparatus of the present invention, it is not necessary to measure the natural frequencies of the longitudinal vibration and the bending vibration, and one end of the piezoelectric actuator to be inspected is measured. The motion can be easily inspected simply by acquiring the vibration locus and comparing it with the normal vibration locus. Further, in the piezoelectric actuator inspecting method and the piezoelectric actuator inspecting apparatus according to the present invention, a non-contact method such as a laser Doppler vibrometer can be used to obtain the vibration locus, and the piezoelectric actuator to be inspected is inspected. It is not necessary to provide an electrode or the like, and it is possible to easily inspect a piezoelectric actuator already attached to the device.

By the way, the natural frequencies of the longitudinal vibration and the bending vibration of the piezoelectric actuator fluctuate according to the load applied to the piezoelectric actuator. That is, at the time of manufacturing the piezoelectric actuator, even if each natural frequency is within the standard, when the piezoelectric actuator drives the drive target, repulsive force (load) from the drive target is applied to the piezoelectric actuator, Each natural frequency fluctuates. Therefore, in the conventional piezoelectric actuator inspection method, the operation when the piezoelectric actuator attached to the device drives the drive target is not guaranteed.

On the other hand, according to the piezoelectric actuator inspection method and the piezoelectric actuator inspection apparatus of the present invention, the vibration locus when the piezoelectric actuator drives the drive target of the attached device, that is, the actual use A vibration locus according to the aspect is acquired, and whether or not the piezoelectric actuator to be inspected is a non-defective item is acquired from the vibration locus,
In other words, it is judged whether or not it is operating normally,
If it is determined that the operation is normal, the operation when the piezoelectric actuator is attached to the device to drive the drive target is guaranteed.

Here, in the piezoelectric actuator inspecting method and the piezoelectric actuator inspecting apparatus according to the present invention, the normal vibration locus has a width so as to include each of the vibration loci of the plurality of piezoelectric actuators that operate as non-defective products. When the vibration locus to be inspected is not included in the normal vibration locus, it is desirable that the operation of the piezoelectric actuator to be inspected be a malfunction.

In order to achieve the above object, the present invention combines a longitudinal vibration having a longitudinal direction and vibrating in the longitudinal direction with a bending vibration bending in a width direction orthogonal to the longitudinal direction. In a method of adjusting a natural frequency of a bending vibration of a piezoelectric actuator that generates a vibration, a vibration locus when a piezoelectric actuator that operates as a non-defective product drives an object by vibration is acquired as a normal vibration locus. Process 1, a second process of acquiring a vibration locus when the piezoelectric actuator to be adjusted drives the object by vibration, a normal vibration locus acquired in the first process, and the second process The vibration loci acquired in the process are compared, and when the deviation between the vibration loci of both is out of a certain range, the piezoelectric actuator of the adjustment target It provides a preparation method of a piezoelectric actuator and a fourth step of adjusting the weight balance in the longitudinal direction.

In the fourth step, when increasing the natural frequency of the flexural vibration, the bias of the weight balance is reduced, while when decreasing the natural frequency of the flexural vibration, the weight balance is decreased. Increase the bias. The adjustment of the deviation of the weight balance is preferably performed by laser trimming, and the adjustment of the weight balance is also preferably performed by mechanical trimming. Further, the piezoelectric actuator to be inspected is
It is preferable to provide a member to be trimmed by an amount according to the result of the comparison in the above step 3. According to this method for adjusting a piezoelectric actuator, in the third step, the piezoelectric actuator which has malfunctioned is adjusted so as to draw a normal vibration locus.

In order to achieve the above-mentioned object, the present invention provides a vibration in which a longitudinal vibration having a longitudinal direction and vibrating in the longitudinal direction and a bending vibration bending in the longitudinal direction are combined. In the method of adjusting a piezoelectric actuator, which is generated and adjusts the natural frequency of the bending vibration of the piezoelectric actuator mounted on the calendar mechanism of the portable timepiece by the support member having the longitudinal direction, the piezoelectric actuator that operates as a non-defective product is subject to vibration. A first step of acquiring a vibration locus when driving a normal vibration locus, and a second step of acquiring a vibration locus when a piezoelectric actuator to be inspected drives the object by vibration.
The normal vibration locus obtained in the first step and the vibration locus obtained in the second step are compared, and when the deviation of the two vibration loci is out of a certain range, the longitudinal direction of the support member is increased. Fourth trimming in the width direction orthogonal to each other
And a method for adjusting a piezoelectric actuator, the method including: As described above, when the width direction of the support member is shaved, the restraining force of the piezoelectric actuator by the support member becomes weak, and the natural frequency of the bending vibration decreases. Thereby, the natural frequency of the bending vibration can be brought close to the natural frequency of the longitudinal vibration.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments,
A case where the piezoelectric actuator to be inspected is attached to the calendar display mechanism of the wristwatch will be exemplified.

FIG. 1 is a plan view showing the main structure of a calendar display mechanism in which a piezoelectric actuator is incorporated in the structure of a wristwatch. The piezoelectric actuator A1 is a diaphragm 1 that expands and contracts in an in-plane direction (direction parallel to the plane of the drawing).
It has 0. One end of the vibration plate 10 is in contact with the rotor 100 that is a drive target. The rotor 100 is rotatably supported by the main plate 103, and the vibration plate 10
When the outer peripheral surface of the vibrating plate 10 is struck by vibration generated in the vibrating plate 10, the vibrating plate 10 is rotationally driven in a direction indicated by an arrow in the figure. The detailed structure of the piezoelectric actuator A1 will be described later.

The calendar display mechanism is connected to the piezoelectric actuator A1 and is driven by its driving force. The main part of the calendar display mechanism is roughly composed of a reduction gear train that reduces the rotation of the rotor 100 and a ring-shaped date wheel 50. The reduction gear train includes a date driving intermediate wheel 40 and a date driving wheel 60. With such a structure, when the diaphragm 10 vibrates in the in-plane direction, the rotor 100 in contact with the diaphragm 10 is rotated clockwise. The rotation of the rotor 100 is transmitted to the date indicator driving wheel 60 via the date indicator driving intermediate wheel 40, and the date indicator driving wheel 60 rotates the date indicator 50 in the clockwise direction.

FIG. 2 is a diagram showing the structure of the piezoelectric actuator. As shown in the figure, the piezoelectric actuator A1
Is a diaphragm 1 in the shape of a long plate formed long in the left-right direction in the figure.
0 and a support member 11 that supports the vibration plate 10 on the main plate 103 (see FIG. 1). This support member 11
Is formed of a metal such as stainless steel. A protrusion 36 made of metal such as stainless steel is provided on the end portion 35 of the vibration plate 10 in the longitudinal direction of the rotor 100.
Projecting toward the side of the rotor 1.
00 is in contact with the outer peripheral surface. By providing such protrusions 36, only the protrusions 36 need to be polished in order to maintain the state of the contact surface with the rotor 100, etc., so that the management of the contact portion with the rotor 100 is easy. Becomes Further, by providing such a protrusion 36, the weight balance of the diaphragm 10 is imbalanced, and the protrusion 36 moves along an elliptical orbit as described later in detail. .

One end portion 37 of the support member 11 is attached to the rotor 100, which is slightly closer to the rotor 100 side than the longitudinal center thereof. The other end 38 of the support member 11 has a screw 39
Is supported by the main plate 103 (see FIG. 1). Under this structure, the support member 11 supports the diaphragm 10 in a state of being urged toward the rotor 100 by its elastic force,
As a result, the protrusion 36 of the diaphragm 10 is brought into contact with the side surface of the rotor 100. When the protruding portion 36 brought into contact with the rotor 100 is displaced in this manner, the rotor 100 and the protruding portion 3 are also caused by friction between the rotor 100 and the protruding portion 36.
6 and is driven to rotate in the direction indicated by the arrow in FIG.

As shown in FIG. 3, the vibration plate 10 has the same shape as the piezoelectric elements 30 and 31 between the two rectangular piezoelectric elements 30 and 31, and the piezoelectric elements 30 and 31 have the same shape.
It has a laminated structure in which a reinforcing plate (reinforcing portion) 32 such as stainless steel having a smaller thickness than 31 is arranged. By disposing the reinforcing plate 32 between the piezoelectric elements 30 and 31 as described above, the vibration plate 1 caused by the over-amplitude of the vibration plate 10 or the external force is generated.
0 damage can be reduced. Further, as the reinforcing plate 32, one having a smaller thickness than the piezoelectric elements 30 and 31 is used so that the vibration of the piezoelectric elements 30 and 31 is not disturbed as much as possible.

Electrodes 33 are respectively arranged on the surfaces of the piezoelectric elements 30 and 31 arranged vertically. A voltage is supplied to the piezoelectric elements 30 and 31 via the electrode 33. Here, as the piezoelectric elements 30 and 31, lead zirconate titanate (PZT (trademark)), crystal, lithium niobate, barium titanate lead titanate,
Lead metaniobate, polyvinylidene fluoride, zinc lead niobate ((Pb (Zn1 / 3-Nb2 / 3) 03 1-x-Pb Ti03 x) x depends on the composition. X = 0.09), scandium lead niobate ( (Pb ((Sc1 / 2Nb1 / 2) 1-x Tix)) 03) x depends on the composition. x = 0.09) or the like.

The diaphragm 10 having such a structure is adapted to vibrate when the piezoelectric elements 30 and 31 expand and contract when an alternating voltage is applied to the piezoelectric elements 30 and 31 from the drive circuit via the electrodes 33. ing. At that time, as shown in FIG. 4, the diaphragm 10 vibrates by longitudinal vibration that expands and contracts in the longitudinal direction, whereby the diaphragm 10 vibrates in the direction indicated by the arrow in FIG. When an alternating voltage is applied to the piezoelectric elements 30 and 31 in this way to excite longitudinal vibration, bending vibration in the width direction is induced in the vibrating plate 10 due to the imbalance of the weight balance of the vibrating plate 10, as shown in FIG. Will be done. Specifically, when the vibration plate 10 vibrates longitudinally, a rotational moment about its fulcrum (the center of gravity when no load is applied) acts, and the bending vibration as shown in the drawing is induced in the vibration plate 10. ing. When such a longitudinal vibration and a bending vibration occur and they are coupled, the protrusion 36 of the diaphragm 10 moves along an elliptical orbit as shown in FIG.

In order to induce bending vibration in the diaphragm 10, the piezoelectric elements 30 and 31 have an alternating current having a frequency intermediate between the natural frequency fa of longitudinal vibration and the natural frequency fb of bending vibration. A voltage needs to be applied. FIG. 7 is a diagram showing an example of the relationship between the vibration frequency of the diaphragm 10 and the impedance. As shown in the figure, the natural frequency fa, which is the minimum value of the impedance in the longitudinal vibration mode, and the natural frequency fb, which is the minimum value of the impedance in the bending vibration mode.
And have different values. Therefore, the natural frequency f
If the piezoelectric elements 30 and 31 are driven at a frequency fb ′ between the frequency f1 at which the impedance has a maximum value between a and the natural frequency fb, and the natural frequency fb in the bending vibration mode, the piezoelectric elements 30 and 31 are driven. Along with longitudinal vibration of 30, 31, bending vibration is induced. Furthermore, since the piezoelectric elements 30 and 31 are driven at the frequency fb ′ close to the natural frequency fb of bending vibration, large bending vibration is induced, and the protrusion 36 of the diaphragm 10 draws a larger ellipse. . In this way, the ellipse drawn by the protrusion 36 becomes large, so that the protrusion 3
6, the rotational force applied to the rotor 100 also increases, and the driving efficiency (the amount of electric power supplied to the piezoelectric elements 30 and 31 versus the number of rotations of the rotor 100) increases.

Now, the inspection apparatus according to the present embodiment detects the elliptical orbit drawn by the projection 36 of the piezoelectric actuator A1 to be inspected and judges whether this elliptical orbit is normal or not. FIG. 8 is a block diagram showing the functional configuration of the inspection apparatus according to this embodiment. As shown in the figure, the inspection device 200 includes a control unit 202. The control unit 202 includes a CPU (Central Processing Uni
t) and other control means, and RAM (Random Access Memory)
And a storage unit such as a ROM (Read Only Memory) and controls the operation of each unit of the inspection apparatus 200. Display unit 208
Has a CRT (Cathode Ray Tube) display or a liquid crystal display, for example, and displays various information under the control of the control unit 202.

The vibration measuring unit 204 measures the movement speed of the protrusion 36 of the piezoelectric actuator A1 due to the vibration without contact, and outputs the measurement result to the control unit 202. Specifically, as shown in the figure, the vibration measuring unit 204 includes two laser Doppler vibrometers 300-X and 300-Y. Laser Doppler vibrometer 300-X, 300-Y
Each includes a laser light source such as an LD (Laser Diode). As illustrated in FIG. 9, when the laser Doppler vibrometer 300-X receives a measurement start command from the control unit 202, the laser Doppler vibrometer 300-X emits the laser beam Rx from the X-axis direction toward the protrusion 36 of the piezoelectric actuator A1 that is vibration-driven. Irradiate. Then, the laser Doppler vibrometer 300 detects the movement speed of the projection 36 in the X-axis direction at regular time intervals from the Doppler shift amount of the returned light, and sequentially outputs it to the control unit 202 as an X-axis speed signal at each time. To do.

On the other hand, laser Doppler vibrometer 300-Y
When receiving the measurement start command from the control unit 202, irradiates the two protrusions 36 of the piezoelectric actuator A1 that are oscillatingly driven with two laser beams Ry1 and Ry2 from the X-axis direction. The laser light Ry2 is obtained by splitting the laser light Ry1 with a beam splitter or the like, and has the same phase as the laser light Ry1. The laser Doppler vibrometer 300-Y detects the moving speed of the protrusion 36 in the Y-axis direction at regular intervals from the time variation of interference fringes (fringes) obtained by interfering the respective return lights,
It is output to the control unit 202 as a Y-axis speed signal for each time. Here, the laser Doppler vibrometer 300-X, 30
The measurement time intervals of 0-Y are set to be equal to each other, and the laser Doppler vibrometers 300-X and 300-Y are set.
Each of them detects the movement speed of the protrusion 36 at approximately the same time. Note that, in FIG. 9, the laser light from each of the laser Doppler vibrometers 300-X and 300-Y is illustrated so as to be incident substantially parallel to the main plate 103 toward the protrusion 36. However, in practice, the laser Doppler vibrometers 300-X, 3
In order to prevent the laser light from each of 00-Y from being blocked by each part of the calendar display mechanism such as the date indicator 50,
These laser lights obliquely enter the main plate 103.

In FIG. 8, the control unit 202 time-integrates the X-axis velocity signal and the Y-axis velocity signal for each fixed time to obtain the X-axis displacement amount and the Y-axis displacement amount for each time, and the constant is obtained. The vibration locus of the protrusion 36 is specified from the X-axis displacement amount and the Y-axis displacement amount for each time. The storage unit 206 is a storage device such as a magnetic disk or a magneto-optical disk, and stores various data. The data stored in the storage unit 206 is, for example, a normal vibration locus data table TBL1 obtained from the normal vibration locus of the piezoelectric actuator A1 incorporated in the calendar display mechanism.

FIG. 10 is a diagram showing an example of a vibration locus of the protrusion 36, that is, an example of a normal vibration locus when the normally operating piezoelectric actuator A1 is incorporated in the calendar display mechanism. FIG. 11 is a schematic diagram showing the configuration of the normal vibration trajectory table. As shown in FIG. 10, the vibration locus of the piezoelectric actuator A1 that operates normally is an elliptical locus. In the present embodiment, the normal elliptical locus is provided with a predetermined width (shown by diagonal lines in the figure). This width is set so as to include a vibration locus that can be regarded as normally driving the rotor 100. That is, if the vibration locus of the piezoelectric actuator is included in the normal ellipse locus, the piezoelectric actuator is assumed to operate normally.

Further, as shown in FIG. 11, the normal vibration locus data table TBL1 records the correspondence between the X coordinate and the Y coordinate of the normal vibration locus. Here, since the normal vibration trajectory draws an ellipse, there may be two Y coordinate ranges corresponding to one X coordinate (indicated by Xa in the figure). For example, as shown in FIG. 9, the X coordinate is X coordinate X.
When the two coordinates of a and the X coordinate Xb are determined, the X coordinate Xa corresponds to two Y coordinate ranges Y1a to Y1a 'and Y2a to Y2a'. On the other hand, the Y coordinate corresponding to the X coordinate Xb is one Y coordinate range of Y1b to Y1b ′. In the following description, this Y coordinate range is referred to as a “normal Y coordinate range”. The normal vibration locus shown in FIG. 10 is merely an example when the piezoelectric actuator A1 is incorporated in the calendar mechanism. That is, the normal vibration locus may be set to be different for each device in which the piezoelectric actuator A1 is incorporated.

Now, with such a configuration, the inspection device 20
0 detects the vibration locus of the piezoelectric actuator A1 to be inspected and inspects the vibration state of the piezoelectric actuator A1. FIG. 12 is a flowchart showing a processing operation procedure of the CPU 202 of the inspection device 200. As shown in the figure, first, the control unit 202 outputs a measurement start command to the vibration measuring unit 204 (step S1). Laser Doppler vibrometer 300-X, 300- of vibration measuring unit 204
When each of the Ys receives the measurement start command, each Y measures the motion velocity due to the vibration of the protrusion 36 of the piezoelectric actuator A1 to be inspected. That is, the laser Doppler vibrometer 300-X measures the displacement speed of the protrusion 36 in the X-axis direction at regular time intervals, and outputs the X-axis speed signal at each time.
Output to 2. In addition, laser Doppler vibrometer 300-
Y measures the displacement speed of the protrusion 36 in the Y-axis direction at regular time intervals, and outputs a Y-axis speed signal to the control unit 202 at each time interval.

The control unit 202 time-integrates each X-axis velocity signal received from the laser Doppler vibrometer 300-X to obtain an X-axis displacement amount at constant time intervals, while receiving from the laser Doppler vibrometer 300-Y. The respective Y-axis velocity signals are time-integrated to obtain the Y-axis displacement amount at constant time intervals, and the vibration locus of the piezoelectric actuator A1 to be inspected is specified from each of the X-axis displacement amount and the Y-axis displacement amount (step S2). ), And the control unit 202 creates a measurement data table TBL2 in the RAM from this vibration locus (step S).
3). FIG. 13 is a schematic diagram showing the configuration of the measurement data table TBL2. As shown in the figure, in the measurement data table TBL2, the vibration locus specified in step S2 is recorded as coordinate information. That is, the measurement data table TBL2 is associated with the X coordinate value (hereinafter, referred to as “measurement X coordinate value Xs”) of the vibration locus and the Y coordinate value (hereinafter, referred to as “measurement Y coordinate value Ys”). There is.

Now, the control unit 202 carries out the following processing from the normal vibration locus data table TBL11 and the measurement data table TBL2 to judge whether the piezoelectric actuator A1 to be inspected is normally vibrating. That is, the control unit 202 extracts the top record from the measurement data table TBL2 (step S4). Next, the control unit 202 determines whether or not the measured Y coordinate value Ys recorded in this record is included in the normal Y coordinate range. Specifically, the control unit 202 searches each record of the normal vibration locus data table TBL1 using the measured X coordinate value Xs of this record as a search key for the X coordinate, and extracts the corresponding record (step S5). Then, the control unit 202 controls the normal Y recorded in the extracted record.
It is determined whether the measurement Y coordinate value Ys is included in the coordinate range (step S6). If the result of this determination is "YES", the control unit 202 determines whether the record processed in steps S5 and S6 is the last record in the measurement data table TBL2 (step S7). If the determination result is “NO”, the control unit 202 retrieves the next record from the measurement data table TBL2 to process the next record (step S8), and returns the processing procedure to step S5.

The determination result in step S6 is "NO".
If so, the vibration operation of the piezoelectric actuator A1 to be inspected is not normal, so the control unit 202 causes the display unit 208 to display that the piezoelectric actuator A1 is malfunctioning (step S9). If the determination result in step S7 is "YES", the vibration operation of the piezoelectric actuator A1 to be inspected is normal, and therefore the control unit 2
02 causes the display unit 208 to display that the operation of the piezoelectric actuator A1 is normal (step S10).

Thus, the inspection device 200 of this embodiment
Is a non-defective piezoelectric actuator because it is judged from the vibration locus when the piezoelectric actuator A1 actually drives the drive target (the rotor 100 of the calendar display mechanism of the wristwatch in this embodiment). If it is determined that the piezoelectric actuator is incorporated in the device, the operation when driving the drive target is guaranteed. Further, according to the inspection device 200, it is not necessary to measure the natural frequencies of the longitudinal vibration and the bending vibration, and the inspection device 2
00 acquires the vibration locus of one end of the piezoelectric actuator to be inspected, and the operation of the piezoelectric actuator is easily inspected simply by comparing this with a normal vibration locus. Furthermore, since the inspection apparatus 200 acquires the vibration locus of the piezoelectric actuator A1 using the laser Doppler vibrometers 300-X and 300-Y, which are non-contact methods, even if the piezoelectric actuator is incorporated in the apparatus. , Can be easily inspected. Note that the piezoelectric actuator to be inspected does not have to be actually incorporated in the device as long as it drives an object equivalent to the object to be actually driven. Here, the object equivalent to the driven object means an object designed such that the repulsive force received by the piezoelectric actuator from the driven object is substantially equal.

When the natural frequency fa of the longitudinal vibration of the piezoelectric actuator A1 and the natural frequency fb of the bending vibration are close to each other, the vibration locus of the piezoelectric actuator A1 is close to an ellipse. However, when the natural frequencies of the piezoelectric actuators A1 and A2 are far from each other, the vibration locus of the piezoelectric actuator A1 deviates from the elliptical orbit, and the piezoelectric actuator A1 does not normally vibrate. Therefore, when the vibration locus of the piezoelectric actuator A1 specified in step S2 is away from the elliptical orbit, the natural frequency fb of the bending vibration is
Can be adjusted so that the piezoelectric actuator A1 normally vibrates by bringing the natural frequency fa close to the natural frequency fa.

Specifically, the width of the support member 11 is adjusted according to the specified vibration locus. FIG. 14 shows the support member width W.
It is a figure which shows an example of the relationship between and the natural frequency fb of bending vibration. As shown in the figure, as the support member width W becomes narrower, the constraining force of the piezoelectric actuator A1 by the support member 11 becomes smaller, so that the natural frequency fb of the bending vibration also becomes smaller. In this way, by adjusting the support member width W,
The natural frequency fb of the bending vibration is also adjusted. Therefore, when the natural frequency fb of the flexural vibration is specified to be higher than the natural frequency of the longitudinal vibration from the vibration locus of the piezoelectric actuator A1 to be inspected, the width direction of the support member 11 is used for processing such as YAG laser. By trimming with a laser, the natural frequency fb of the bending vibration can be brought close to the natural frequency of the longitudinal vibration, and the piezoelectric actuator A1 can be caused to normally vibrate.

By the way, the natural frequency fb of the bending vibration cannot be increased by the method of adjusting the natural frequency fb such as trimming the support member width W. Therefore, if the width of the support member 11 is made larger than the design value in advance, the natural frequency fb of flexural vibration is always larger than the natural frequency fa of longitudinal vibration. In this way, if the width direction of the support member 11 is trimmed in accordance with the vibration locus of the piezoelectric actuator A1 and the natural frequency fb of bending vibration is adjusted to be lower, the natural frequency fb of bending vibration becomes longer. Since the natural frequency fa of the vibration is approached, the piezoelectric actuator A1 can be adjusted to operate normally.

<Modification> The above-described embodiment shows one aspect of the present invention, and can be arbitrarily modified within the scope of the present invention. Therefore, various modifications will be described below.

(Modification 1) In the above-described embodiment,
The case where the inspection device 200 inspects the vibration state of the piezoelectric actuator A1 incorporated in the calendar display mechanism of the wristwatch has been exemplified, but the device in which the piezoelectric actuator A1 is incorporated is not limited to this, and an inkjet nozzle of a printer or a mobile phone. It may be any electronic device such as. Further, the inspection apparatus 200 measures the vibration locus of the protrusion 36 of the piezoelectric actuator A1, but not limited to this, it may measure the vibration locus of the end portion 35 of the diaphragm 10 in the piezoelectric actuator A1.

(Modification 2) In the inspection apparatus 200 according to the above-described embodiment, the laser beam is used for trimming the support member 11. However, the invention is not limited to this, and for example, mechanical processing such as wire saw or dicing. The device may be used. The member to be trimmed is not limited to the support member 11. More specifically, since the flexural vibration of the piezoelectric actuator A1 is induced by the rotational moment resulting from the imbalance of the weight balance in the longitudinal direction of the diaphragm 10, its natural frequency fb is
It depends on the rotation moment of the diaphragm 10. That is, if the rotational moment is changed by adjusting the weight balance of the diaphragm 10, the natural frequency fb of the bending vibration is also changed. Therefore, the inspection apparatus 200 may trim the diaphragm 10 so as to increase or decrease the weight balance, instead of trimming the support member 11.

More specifically, the natural frequency of object vibration due to the moment of inertia generally increases as the moment of inertia decreases. Therefore, the inspection device 200
When the adjustment is made to increase the natural frequency fb of the bending vibration, the protrusion 3 is to reduce the weight balance of the diaphragm 10.
The vicinity of the end portion 35 where 6 is provided is trimmed. Also,
The inspection device 200 trims the vicinity of the end portion opposite to the end portion 35 provided with the protrusion 36 in order to increase the weight balance of the diaphragm 10 when adjusting the natural frequency fb of the bending vibration to be low. To do. It should be noted that which part of the diaphragm 10 is trimmed by the inspection device 200 in order to adjust the weight balance is arbitrary. However, it is desirable that the portions of the diaphragm 10 other than the electrodes be trimmed. Further, in the manufacturing process of the piezoelectric actuator A1, for example, a metal such as copper or gold is vapor-deposited on the end portion 35, and the vapor-deposited portion is removed by laser irradiation or the like according to the specified vibration locus, thereby reducing the weight. You may adjust the balance.

(Modification 3) In the above-described embodiment,
The inspection device 200 includes a piezoelectric actuator A1 to be inspected.
When comparing the vibration locus of No. 1 and the normal vibration locus, it was determined whether the coordinates of the vibration locus are included in the normal vibration locus. Not limited to this, the inspection apparatus 200 may represent each vibration locus by image data and compare each image data. Further, the piezoelectric actuator A1 drives the rotor 100 by the contact and separation of the tip end portion 36 with respect to the rotor 100 repeatedly. Therefore, if the trajectory drawn during the period in which the tip portion 36 contacts the rotor 100 is normal, the rotor 100 is driven normally. Therefore,
The inspection device 200 determines that the rotor 1 is included in the identified vibration locus.
Only the portion corresponding to the contact period with 00 may be compared with the normal vibration locus.

[0043]

As described above, according to the present invention,
Provided are an inspection method capable of easily and accurately inspecting the vibration of a piezoelectric actuator, an adjusting method for adjusting the vibration of the piezoelectric actuator according to the inspection result, and an inspection device.

[0044]

[Brief description of drawings]

FIG. 1 is a plan view showing a main configuration of a calendar display mechanism including a piezoelectric actuator in a wristwatch.

FIG. 2 is a plan view showing the overall configuration of the piezoelectric actuator.

FIG. 3 is a side sectional view showing a diaphragm which is a component of the piezoelectric actuator.

FIG. 4 is a diagram showing how the diaphragm vibrates vertically.

FIG. 5 is a diagram for explaining flexural vibration induced by longitudinal vibration of the diaphragm.

FIG. 6 is a diagram showing how the tip portion of the piezoelectric actuator operates.

FIG. 7 is a diagram showing an example of a relationship between a vibration frequency and an impedance of the diaphragm.

FIG. 8 is a block diagram showing a functional configuration of the inspection device according to the embodiment of the present invention.

FIG. 9 is a diagram for explaining measurement of the same vibration locus.

FIG. 10 is a view showing the normal vibration locus.

FIG. 11 is a schematic diagram showing a configuration of the normal vibration locus data table.

FIG. 12 is a flowchart showing a processing procedure executed by the inspection apparatus.

FIG. 13 is a schematic diagram showing the configuration of the measurement data table.

FIG. 14 is a diagram showing an example of the relationship between the support member width and the natural frequency of bending vibration.

[Explanation of symbols]

A1 ... Piezoelectric actuator, TBL1 ... Normal vibration locus data table, TBL2 ... Measurement data table, 10 ...
Vibration plate 11, 11 ... Support member, 35 ... Projection 36 ... Projection,
30 ... Piezoelectric element, 32 ... Reinforcing plate, 100 ... Rotor, 20
0 ... Inspection device, 202 ... CPU, 204 ... Vibration locus measuring unit, 206 ... Storage unit, 208 ... Display unit, 300-X, 3
00-Y ... Laser Doppler vibrometer

Continued front page    (72) Inventor Kunihiko Takashiro             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation F term (reference) 2F069 AA06 BB40 CC05 DD08 DD30                       EE04 EE26 FF07 GG04 GG63                       GG72 GG74 GG77 HH09 NN09                       QQ03                 5D107 AA20 BB06 CC01 DD03 FF01                 5H680 AA10 BB04 BB13 BB20 BC02                       CC02 DD02 DD15 DD23 DD37                       DD63 DD66 DD82 FF26 GG02

Claims (11)

[Claims] 1. A first process of acquiring a vibration locus as a normal vibration locus when a piezoelectric actuator that operates as a non-defective product drives an object by vibration, and a piezoelectric actuator that is an inspection target drives the object by vibration. The second process of obtaining the vibration locus at the time, the normal vibration locus obtained in the first process, and the vibration locus obtained in the second process are compared, and the deviation between the two vibration loci is within a certain range. Thirdly, if the operation is outside, the operation of the piezoelectric actuator to be inspected is regarded as a malfunction.
The method for inspecting a piezoelectric actuator, comprising: 2. The normal vibration locus has a width so as to include each of the vibration loci drawn by a plurality of piezoelectric actuators that operate in good quality, and the vibration locus acquired in the second process in the third process is If it is not included in the normal vibration locus,
The method of inspecting a piezoelectric actuator according to claim 1, wherein the operation of the piezoelectric actuator to be inspected is a malfunction. 3. In the third step, of the vibration locus obtained in the second step, only the portion drawn when the piezoelectric actuator to be inspected is in contact with the object is the normal path. The method for inspecting a piezoelectric actuator according to claim 1 or 2, wherein the method is compared with a vibration locus. 4. A flexural vibration of a piezoelectric actuator which has a longitudinal direction and which generates a vibration by combining a longitudinal vibration vibrating in the longitudinal direction and a flexural vibration bending in a width direction orthogonal to the longitudinal direction. In a method of adjusting a piezo-electric actuator for adjusting a natural frequency, a first step of acquiring a vibration locus as a normal vibration locus when a non-defective piezoelectric actuator drives an object by vibration, A second process of obtaining a vibration locus when driving the object by vibration, a normal vibration locus obtained in the first process, and a vibration locus obtained in the second process are compared, and both are compared. Adjusts the weight balance in the longitudinal direction of the piezoelectric actuator to be adjusted when the deviation of the vibration locus of is outside a certain range. 4. A method for adjusting a piezoelectric actuator, which comprises the step 4). 5. In the fourth step, when increasing the natural frequency of the flexural vibration, the bias of the weight balance in the longitudinal direction of the piezoelectric actuator to be adjusted is reduced while the natural frequency of the flexural vibration is reduced. The piezoelectric actuator adjusting method according to claim 4, wherein when the frequency is lowered, a deviation of a weight balance in a longitudinal direction of the piezoelectric actuator to be adjusted is increased. 6. The method for adjusting a piezoelectric actuator according to claim 5, wherein, in the fourth step, the adjustment of the weight balance deviation in the longitudinal direction is performed by laser trimming. 7. The method of adjusting a piezoelectric actuator according to claim 5, wherein, in the fourth step, the deviation of the weight balance in the longitudinal direction is adjusted by mechanical trimming. 8. A portable type having a longitudinal direction and a combination of longitudinal vibration vibrating in the longitudinal direction and flexural vibration bending in the longitudinal direction, and being a portable member having a longitudinal direction. In the method of adjusting the natural frequency of the bending vibration of the piezoelectric actuator attached to the calendar mechanism of the watch, in the piezoelectric actuator that operates as a good product, the vibration locus when the object is driven by vibration is taken as the normal vibration locus. A first step of acquiring, a second step of acquiring a vibration trajectory when a piezoelectric actuator that is an inspection target drives the object by vibration, a normal vibration trajectory acquired in the first step, and The vibration loci acquired in the second process are compared, and if the deviation of the vibration loci of both is out of a certain range, the length of the support member is increased. The fourth to trim the width direction orthogonal to the hand direction
And a method of adjusting a piezoelectric actuator. 9. The method of adjusting a piezoelectric actuator according to claim 8, wherein the trimming is performed by laser trimming. 10. A first acquisition means for acquiring a vibration locus as a normal vibration locus when a non-defective piezoelectric actuator drives an object by vibration, and a piezoelectric actuator to be inspected drives the object by vibration. The second acquisition means for acquiring the vibration locus at the time of performing, the normal vibration locus acquired in the first step, and the vibration locus acquired in the second step are compared, and the deviation of the two vibration loci An inspection device for a piezoelectric actuator, comprising: an output unit that outputs information indicating that the operation of the piezoelectric actuator to be inspected is defective when the piezoelectric actuator is out of a certain range. 11. The normal vibration locus has a width that includes the vibration loci of a plurality of piezoelectric actuators that operate in good quality, and the output means sets the vibration locus acquired by the second acquisition means to the normal vibration locus. 11. The piezoelectric actuator inspection device according to claim 10, wherein, if not included, the operation of the piezoelectric actuator to be inspected is determined to be a malfunction.