JPH1032458A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate at a high frequency and to improve electro-machine conversion efficiency by providing electrodes which extend in the length direction of an oscillation part and which are not brought into contact with each other an parts which are on the surfaces of the oscillation part and which are divided into two by a center line in the width of the oscillation part and constituting a piezoelectric device. SOLUTION: A piezoelectric body, especially a supporting part 11, the oscillation part 12, the first electrode 13, a second electrode 14 and a connection part 15 are provided. The electrodes which extend in the length direction of the oscillation part 12 and which are not brought into contact with each other are provided at the parts which are on the surfaces of the oscillation part 12 and which are divided into two by the center line in the width of the oscillation part 12 so as to constitute a piezoelectric device. The forms of the oscillation part 12 and the connection part 15 are made so that the width of the oscillation part 12 and that of the connection part 15 reduce in a thickness direction. When electric signals are applied to the first electrode 13 and the second electrode 14, the dielectric constant of the piezoelectric body is sufficiently larger than that of air. Thus, the lines of electric force between the two electrodes pass through almost the piezoelectric body. Thus, the efficiency of electro- machine conversion can considerably be improved in the oscillation part 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a piezoelectric device, and more particularly, to a piezoelectric device which can operate at a high frequency of about 50 MHz or higher, has high electro-mechanical conversion efficiency, and can secure mechanical strength.

Generally, the vibration frequency of a piezoelectric device is determined by its physical dimensions. In the case of the sliding vibration mode, the vibration frequency is determined by the width or thickness of the piezoelectric device. As the thickness decreases, mechanical processing becomes difficult, and it becomes difficult to secure the mechanical strength.

However, the speeding up of communication devices has been progressing without knowing where to stop, and there is a strong demand for a piezoelectric device that satisfies these conflicting requirements.

[0004]

2. Description of the Related Art Conventionally, various types of piezoelectric devices have been developed, but typical piezoelectric devices suitable for a high-frequency region include a device in which a piezoelectric material is AT-cut and a device in which a piezoelectric material is SL-cut or HT-cut. Some have done.

FIG. 6 shows a general AT-cut thickness shear vibrator, which utilizes the shear vibration in the thickness direction of a piezoelectric body. FIG. 6 shows a perspective view of a part of the piezoelectric body cut out.

In FIG. 6, reference numeral 101 denotes a piezoelectric flat plate;
02 is a first electrode pattern formed on one surface of the flat plate of the piezoelectric body, 103 is a second electrode formed on the other surface of the piezoelectric body, and 104 and 105 are flat plates of the piezoelectric body. A pair of external lead terminals that support and connect the two electrodes 102 and 103 to the outside.

In the configuration shown in FIG. 6, the two electrodes and the portion of the piezoelectric body sandwiched between the two electrodes are a vibrating section for converting electric field energy and vibration energy of the piezoelectric body. The electrical equivalent circuit of the vibrating portion is a resonance circuit in which an inductance and a capacitance are connected in series and a second capacitance is connected in parallel. Since the outer periphery of the flat plate is unrelated to vibration, an external lead terminal for supporting the flat plate and connecting electrodes to the outside is provided there.

Assuming that A is a constant and t is the thickness of the flat plate of the piezoelectric body, the vibration frequency f of the vibrator having this configuration is given by f = A / t (1). In order to make the vibrator vibrate at the fundamental frequency of 50 MHz, the piezoelectric body needs to be polished to a thickness of about 35 microns.

FIG. 7 shows a monolithic crystal filter (M) using a general AT-cut thickness shear resonator.
CF). In FIG. 7, reference numeral 111 denotes a piezoelectric flat plate;
112 and 113 are signal electrodes formed on one surface of the piezoelectric flat plate, 114 are ground electrodes formed on the other surface of the piezoelectric flat plate, and 115 and 116 connect the two electrodes to the outside. An external lead-out terminal 117 for supporting the flat plate of the piezoelectric body is an external lead-out terminal for connecting the ground electrode to the outside and supporting the flat plate of the piezoelectric body.

Then, the first electrode 112 and the ground electrode 1
A first vibrator is constituted by 14 and the piezoelectric body sandwiched therebetween, and a second vibrator is constituted by the second electrode 113, the ground electrode 114, and the piezoelectric body sandwiched therebetween,
Vibration energy is coupled between the first and second vibrators by the piezoelectric body in a portion between the first electrode and the second electrode. That is, the equivalent circuit of the MCF having the configuration shown in FIG. 7 is represented by a circuit in which the input and output sides have resonance circuits in parallel branches and the two resonance circuits are coupled by a capacitor.

That is, the configuration of FIG. 7 is a so-called multiple resonance circuit. When the resonance frequencies of the two resonance circuits are equal, in the multiple resonance circuit, the resonance frequency is divided into two, and the transmission amount is substantially constant in a specific band, and the band where the transmission amount is substantially constant is the band of each resonance circuit. The change in the transmission amount becomes sharper outside the band in which the transmission amount is wider than the band and the transmission amount is substantially constant, so that a so-called band-pass filter is formed.

FIG. 8 shows a diaphragm type AT-cut thickness-sliding vibrator in which a vibrating portion is thinned by etching to increase the frequency and integrated with a supporting structure. In FIG. 8, 121 is a piezoelectric body, 122 is a vibrating part obtained by thinning the piezoelectric body by etching, 123 is a supporting part that retains the original thickness of the piezoelectric body, and 124 is on one surface of the vibrating part. The first electrode 125 formed is not visible in the drawing, but is a second electrode formed on the other surface of the vibrating part.

Although not shown in FIG. 8, a feature of the vibrator of FIG. 8 is that an external lead-out terminal can be provided on a thick portion of the piezoelectric body, that is, a support portion.
Otherwise, the principle of vibration is the same as that of the vibrator having the configuration shown in FIG.

FIG. 9 shows an MCF to which the configuration shown in FIG. 8 is applied. In FIG. 9, 131 is a piezoelectric body, 132 and 133
Is a first and second signal electrode formed on one surface of the vibrating portion of the piezoelectric body, and 134 is a ground electrode formed on the other surface of the vibrating portion of the piezoelectric body.

Although not shown in FIG. 9,
The feature is that an external lead-out terminal can be provided at a place where the piezoelectric body is thick, that is, at the support portion. Otherwise, the principle as a filter is the same as that of the MCF having the configuration shown in FIG.

FIG. 10 shows a general SL-cut or HT-cut width shear oscillator. In FIG.
Is a piezoelectric body, 142 is a first electrode formed on one surface of the piezoelectric body, 143 is not visible in the drawing, but second electrodes 144 and 145 formed on the other surface of the piezoelectric body are An external lead terminal that supports the piezoelectric body and connects the two electrodes to the outside.

The width-slip vibrator oscillates in the longitudinal direction of the vibrator symmetrically with respect to the center line of the width of the vibrator by an electric field applied in the thickness direction. Now, assuming that B is a constant and w is the width of the vibrator, the vibration frequency f of the vibrator is given by f = B / w (2) In order to manufacture a width-slider vibrating at a fundamental frequency of 50 MHz, the width w needs to be about 50 microns.

The vibrator is symmetrical about the center line of its width,
The center line does not oscillate, as it oscillates at the end of its width to maximize the amplitude. Therefore, if an external lead terminal is connected to the center line of the two electrodes, input and output of an electric signal can be performed without damaging the energy of vibration.

FIG. 11 shows an SL-cut or HT-cut width shear oscillator integrated with a support structure using etching. In FIG. 11, reference numeral 151 denotes a piezoelectric body, particularly a supporting portion; 152, a vibrating portion; 153 and 154, connecting portions for mechanically connecting the vibrating portion to the supporting portion; and 155, a first portion formed on one surface of the vibrating portion. One electrode 156 is a second electrode formed on the other surface of the vibrating part, which is not visible in the drawing.

In the configuration shown in FIG. 11, the vibrating portion performs width-shear vibration symmetrical with respect to a center line of the width by an electric field applied between the first and second electrodes. Now, the width w of the vibrating part and the fundamental frequency f of the electric field applied between the two electrodes
Is set so as to satisfy the relationship of the expression (2), if the width of the connecting portion is gradually reduced from the portion connected to the vibrating portion toward the portion connected to the supporting portion, the connecting portion Cannot oscillate at the fundamental frequency. Therefore, the vibration can be confined in the vibrating section, and the efficiency of electro-mechanical conversion in the vibrating section is not impaired.

Also, since the center line of the width of the vibrating portion does not originally vibrate, if the distal end of the connecting portion is located on the center line and the distal end of the connecting portion is connected to the supporting portion, The vibration energy is not impaired by the support.

FIG. 12 shows an MCF to which the configuration of FIG. 11 is applied.
It is. In FIG. 12, reference numeral 161 denotes a piezoelectric body, in particular, a support portion; 162, a first vibrating portion; 163, a second vibrating portion;
64 is a coupling part that couples the vibration energy of the first and second vibration parts, 165 and 166 are connection parts that connect each vibration part to the support part, 167 and 168 are first and second signal electrodes, 169 is a ground electrode, not visible in the figure. The principle of the MCF shown in FIG. 12 as a filter is the same as that of the MCF shown in FIG. 7 or FIG.

FIGS. 13 (a) and 13 (b) are SL-cut or HT-cut width-slip vibrators which are also integrated with the support structure by means of etching, wherein (a) is a perspective view and (2) is a central part of the vibrator. It is sectional drawing.

In FIG. 13, reference numeral 171 denotes a piezoelectric body, particularly a supporting portion; 172, a vibrating portion; 173 and 174, connecting portions;
75 is a first electrode formed on the surface of the vibrating portion, 176
Is a second electrode formed on the back surface of the support portion facing the first electrode.

The features of the configuration shown in FIG. 13 are that the width of the vibrating section is reduced in the thickness direction of the vibrating section, and that the bottom of the vibrating section is mechanically connected to the supporting section. . First, the width of the surface of the vibrating part is determined by the fundamental frequency of the applied electric field (2).
Is set so as to satisfy the relationship, vibration cannot be performed at the fundamental frequency at the position where the width is reduced, so that the vibration energy is not dispersed in the thickness direction. Therefore, the efficiency of the electromechanical conversion in the vibrating portion is not impaired.

Next, when the bottom of the vibrating section is connected to the supporting section, the force for supporting the vibrating section increases, and it is possible to secure mechanical strength. Moreover, if the bottom of the vibrating part is aligned with the center line, the vibrating part can be supported without damaging the vibration energy of the vibrating part.

The vibrating portion whose width changes in the thickness direction of the vibrating portion performs dry etching using plasma or reactive ions from a direction oblique to the surface of the vibrating portion. The details are disclosed in JP-A-07-254838.

FIG. 14 shows an MCF to which the configuration of FIG. 13 is applied.
It is. In FIG. 14, reference numeral 181 denotes a piezoelectric body, particularly a support portion; 182, a first vibrating portion; 183, a second vibrating portion;
84 is a connecting part for mechanically connecting the two vibrating parts, 185
And 186 are first and second signal electrodes formed on one surface of the first and second vibrating portions, and 187 is opposed to the first and second signal electrodes although not shown in the drawing. And a ground electrode formed on the back surface of the supporting portion.

The configuration of FIG. 14 is different from the configuration of FIG. 12 in that the widths of the vibrating portion and the coupling portion are reduced in the thickness direction, and the bottom of the vibrating portion and the coupling portion is a supporting portion. Is that it is mechanically connected to This advantage and the method of manufacturing a vibrator with such a structure have been outlined in the description of FIG.
838 discloses the details.

The principle of the filter of FIG. 14 is the same as that of FIG.

[0031]

In the AT-cut thickness-sliding vibrator shown in FIG. 6, it is necessary to polish the vibrator to a thickness of about 35 microns in order to make the vibration frequency about 50 MHz. Since the diameter of the flat plate is usually about 3 to 5 mm with respect to this thickness, it is difficult to secure the strength against the bending force applied to the flat plate. Accordingly, the frequency band in which the vibrator having the configuration shown in FIG. 6 can be used is naturally limited. Further, it is necessary to provide the external lead-out terminal in a place where the thickness is not large, and there is still a problem in the adhesive strength of the external lead-out terminal.

The same applies to the MCF having the structure shown in FIG. In the case of the AT-cut vibrator integrated with the support structure shown in FIG. 8, the vibrating part can be thinned by etching to increase the vibration frequency, and the supporting part can be set to a thickness that can maintain mechanical strength. Therefore, it is possible to simultaneously increase the frequency and secure the strength.

However, since the thickness of the supporting portion is larger than the thickness of the vibrating portion, it is possible to vibrate at the fundamental frequency even at the portion where the vibrating portion transitions to the supporting portion, and the vibration energy is vibrated. The difficulty is that it is difficult to confine it to the department.

The same applies to the MCF shown in FIG. In the vibrator shown in FIG. 10, the structure of the external lead-out terminal for supporting the vibrator and connecting it to the outside is impossible.
It is difficult to maintain mechanical strength.

The vibrator shown in FIG. 11 has a drawback that the vibration energy is dispersed in the thickness direction of the vibrating portion because the width of the vibrating portion is constant in the thickness direction. In order to reduce the effect of this, it is necessary to reduce the thickness of the vibrating part, but in view of the ease of machining of the whole vibrator, the thickness of the supporting part itself must be reduced, It is still difficult to secure mechanical strength.

The same applies to the MCF shown in FIG. The vibrator shown in FIG. 13 has been invented in order to solve the above problem, but has a thickness of the vibrating portion of 30 to 5 mm.
Since the thickness of the supporting portion is preferably about 0.2 to 0.5 mm with respect to 0 μm, the first electrode formed on the surface of the vibrating portion and the second electrode formed on the back surface of the supporting portion. Is basically large, and it is difficult to keep the efficiency of electro-mechanical conversion in the vibrating part high.

The same applies to the MCF shown in FIG. SUMMARY OF THE INVENTION The present invention provides a vibrator and an MC that can be used at a high frequency, secure mechanical strength, and have high electro-mechanical conversion efficiency in order to solve many problems as described in detail.
F, that is, to provide a piezoelectric device.

[0038]

The principle of the present invention is to integrate a vibrating part and a support part, reduce the width of the vibrating part in the thickness direction, and change the width of the connecting part from the vibrating part to the support part. In the width-slip vibrator where the bottom of the vibrating part is formed on the center line of the width of the vibrating part and the connecting point of the connecting part and the supporting part is formed on the center line of the vibrating part, This is a technique for forming an independent electrode that bisects the surface in the width direction.

According to the principle of the present invention, an electrode can be formed on the surface of a vibrating portion having a small width by a commonly used fine processing technique, so that the distance between the electrodes is reduced and the electric field intensity is increased. The efficiency of the electro-mechanical conversion is increased. That is, the Q of the vibrator is increased, and the selection characteristics can be made sharp even when a filter is formed.

Therefore, it is possible to solve all of the problems of the prior art described in detail in the section of the problem to be solved by the invention.

[0041]

FIG. 1 shows a first embodiment of the present invention, in which (a) is a perspective view and (b) is a cross-sectional view of a central portion of a vibrator.

In FIG. 1, reference numeral 11 denotes a piezoelectric member, in particular, a supporting portion, 12 a vibrating portion, 13 a first electrode formed on the vibrating portion, 14 a second electrode formed on the vibrating portion, and 15 and 1.
Reference numeral 6 denotes a connecting portion that connects the vibrating portion to the support portion.

The vibrator having the structure shown in FIG. 1 can be obtained by subjecting a piezoelectric body to dry etching using plasma or reactive ions to form a vibrating section integrally with a supporting section.

The shape of the vibrating portion and the connecting portion is such that the width of the vibrating portion and the connecting portion decreases in the thickness direction.
The vibrating part has a certain width in the longitudinal direction, but the width of the connecting part decreases as it approaches the connecting point between the vibrating part and the support part.

Since the width of the vibrating portion is reduced in the thickness direction, the vibration frequency of the vibrating portion increases in the thickness direction. Therefore, if an electric field that can oscillate at the fundamental frequency on the surface of the vibrating part is applied, vibration at the fundamental frequency cannot be performed on parts other than the surface of the vibrating part, and the energy of the mechanical vibration is applied to the surface of the vibrating part. Can be confined.

Also, by decreasing the width of the connecting portion from the vibrating portion to the supporting portion, the vibration frequency of the connecting portion becomes higher than the vibration frequency of the vibrating portion. Energy can be confined in the vibrating part.

Therefore, in the vibrator having the structure shown in FIG. 1, the efficiency of electro-mechanical conversion is increased. Moreover, the vibrating part and the connecting part are formed symmetrically with respect to the center line of the width of the vibrating part,
The vibrating part and the bottom of the connecting part are connected to the supporting part on the center line, and the end of the connecting part and the supporting part are connected on the center line, so that the vibration energy is not easily damaged by the supporting. .

In addition, the configuration of FIG. 1 is characterized in that the first electrode and the second electrode are formed so as to bisect the surface of the vibrating portion in the width direction. When an electric signal is applied to the two electrodes formed in the above, the dielectric constant of the piezoelectric body is sufficiently larger than the dielectric constant of air, so that the lines of electric force between the two electrodes almost pass through the piezoelectric body. Become.

For example, in the case of an SL-cut or HT-cut width-sliding vibrator vibrating at 50 MHz, the width of the surface of the vibrating part is about 50 μm, and two electrodes are placed on the surface with a processing accuracy of a micron unit. Therefore, in the case of the same signal voltage, the electric field strength in the vibrating portion in the piezoelectric body can be increased as compared with the vibrator having the configuration shown in FIG.

Therefore, in the vibrator having the structure shown in FIG. 1, the efficiency of electro-mechanical conversion can be further increased. FIG. 2 shows a second embodiment of the present invention.

In FIG. 2, reference numeral 21 denotes a piezoelectric member, in particular, a support portion, 22 a first vibrating portion, 23 a second vibrating portion, and 24 a mechanical vibration of the first vibrating portion and the second vibrating portion. Coupling portions for coupling energy, 25 and 26, are first and second electrodes formed on the surface of the first and second vibrating portions, respectively.
7 is a ground electrode formed so as to connect the surfaces of the first and second vibrating parts, 28 and 29 are connecting parts for connecting each of the two vibrating parts to the supporting part, and 30 is the grounding part. This is a bonding wire for leading the electrode to the electrode formed on the support.

In the configuration of FIG. 2, an equivalent resonance circuit is formed between the first electrode and the ground electrode, and an equivalent resonance circuit is also formed between the second electrode and the ground electrode. Thus, a multiple resonance circuit is formed in which the two equivalent resonance circuits are coupled by the equivalent capacitance of the coupling unit. This forms a band-pass filter having the band-pass characteristic in the configuration of FIG.

In the configuration of FIG. 2, the structural relationship between the vibrating portion, the coupling portion, the connecting portion, and the support portion is the same as that of FIG.
The relationship between the first electrode and the ground electrode and the relationship between the second electrode and the ground electrode are the same as those in FIG. Accordingly, the MCF having the configuration shown in FIG. 2 has exactly the same advantages as the configuration shown in FIG.

FIG. 3 shows a third embodiment of the present invention. In FIG. 3, reference numeral 31 denotes a piezoelectric body, particularly a support portion, 32 denotes a first vibrating portion, 33 denotes a second vibrating portion, 34 denotes a first electrode formed on the surface of the first vibrating portion, and 35 denotes the first electrode. A second electrode formed on the surface of the second vibrating portion, 36 is a common electrode formed continuously with the rest of the first and second electrodes, and 37 is between the common electrode and the ground. The capacitors to be inserted, 38 and 38a, are a pair of first connecting portions that connect the first vibrating portion and the supporting portion, and 39 and 39a are a pair of second connecting portions that connect the second vibrating portion and the supporting portion. It is a connection part.

In the configuration shown in FIG. 3, the first vibrating portion between the first electrode and the common electrode forms a resonance circuit to form a series branch,
A band-pass filter is formed in which the second vibrating portion between the second electrode and the common electrode forms a resonance circuit to form a series branch, and the capacitor between the common electrode and the ground forms a parallel branch.

In the configuration of FIG. 3, the structural relationship between the vibrating portion, the coupling portion, the connecting portion, and the support portion is the same as that of FIG.
The relationship between the first electrode and the common electrode and the relationship between the second electrode and the common electrode are the same as those in FIG. Therefore, the MCF having the configuration shown in FIG. 3 has exactly the same advantages as the configuration shown in FIG.

Although FIG. 3 shows an example in which two vibrating parts are formed on the same piezoelectric body, the number of vibrating parts to be formed is basically not limited, What is necessary is just to form the number of vibrating parts matching the characteristic to be performed.

So far, a piezoelectric device that can be used up to a high frequency range and can secure mechanical strength has been described. However, a piezoelectric device that can be used in a low-frequency region can be configured with a structure similar to that described above.

FIG. 4 shows a fourth embodiment of the present invention. In FIG. 4, reference numeral 41 denotes a supporting portion, 42 denotes a vibrating portion, and 43 and 44 denote first and second electrodes formed on the surface of the vibrating portion.

In the configuration shown in FIG. 4, the vibrating portion is cut out of the piezoelectric body into a prism shape, the width of the upper surface is the widest, the width of the bottom surface is the narrowest, and the vibration portion passes through the center line of the width of the upper surface. It is formed symmetrically with respect to a vertical plane. Then, the bottom surface is adhered and fixed to the support portion. Note that a conductive adhesive may be used in a portion where the electrode on the vibrating portion is connected to the electrode on the supporting portion.

Since the vibrating portion is formed by cutting as described above, its size is naturally limited and cannot be used up to a very high frequency. However, the efficiency of electro-mechanical conversion is high and the mechanical strength is also high. A vibrator that can be secured can be obtained.

In the case of FIG. 4, the material of the supporting portion does not need to be a piezoelectric material, but may be a substrate made of, for example, an inorganic substance. FIG. 5 shows a fifth embodiment of the present invention.

In FIG. 5, reference numeral 51 denotes a supporting portion; 52, a first vibrating portion; 53, a second vibrating portion; 54, a first electrode formed on the surface of the first vibrating portion; A second electrode 56 formed on the surface of the second vibrating part, a common electrode formed on the remaining part of the surface of the first and second vibrating parts,
57 is a capacitor inserted between the common electrode and the ground.

The configuration shown in FIG. 5 is a filter having the same equivalent circuit as the configuration shown in FIG. The configuration in FIG. 5 is based on the same configuration principle as in FIG. Therefore, further description is omitted here.

[0065]

As described above in detail, according to the present invention, a piezoelectric device which can be used at a high frequency, has high electro-mechanical conversion efficiency, and can secure mechanical strength can be realized. Therefore, it is possible to provide a high-performance and highly-reliable piezoelectric device for a communication device that operates at a higher speed.

Further, it is possible to provide a piezoelectric device that can be used not only in a high frequency region but also in a low frequency region, and it is possible to contribute to improvement of performance and reliability of a communication device over a wide range.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention.

FIG. 2 shows a second embodiment of the present invention.

FIG. 3 shows a third embodiment of the present invention.

FIG. 4 shows a fourth embodiment of the present invention.

FIG. 5 shows a fifth embodiment of the present invention.

FIG. 6 is a typical AT-cut thickness shear resonator.

7 is an MCF to which the configuration of FIG. 6 is applied.

FIG. 8 is an AT-cut thickness shear vibrator integrated with a support structure.

9 is an MCF to which the configuration of FIG. 8 is applied.

FIG. 10 is a typical SL-cut or HT-cut width shear resonator.

FIG. 11 shows an SL-cut and HT-cut width shear oscillator integrated with a support structure (part 1).

12 is an MCF to which the configuration of FIG. 11 is applied.

FIG. 13 shows an SL-cut and HT-cut width shear oscillator integrated with a support structure (part 2).

14 is an MCF to which the configuration of FIG. 13 is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Piezoelectric body especially support part 12 Vibration part 13 First electrode 14 Second electrode 15 Connection part 16 Connection part

Claims (4)

[Claims] 1. A piezoelectric device comprising: a vibrating portion made of a piezoelectric material having a surface width set in a predetermined relationship with a vibration frequency; and a support portion connected to the vibrating portion; A piezoelectric device, wherein electrodes that do not contact each other and extend in the length direction of the vibrating part are provided at a portion bisected by a center line of a width of the vibrating part. 2. The piezoelectric device according to claim 1, wherein the vibrating portion is made of a piezoelectric material having a predetermined width over a predetermined length, and at an end of the vibrating portion, the vibrating portion extends from the end of the vibrating portion. A piezoelectric device, comprising: a vibrating part connected to a connecting part whose width is gradually reduced toward a connecting point to the supporting part. 3. The piezoelectric device according to claim 1, wherein the vibrating portion comprises: two independent electrodes extending in a longitudinal direction of the vibrating portion;
A piezoelectric device comprising: a vibrating section provided with a common electrode independent of each of the two electrodes extending in a length direction of the vibrating section. 4. A plurality of piezoelectric devices according to claim 1, which are connected to a common supporting portion, wherein a center line of a width of the vibrating portion is provided on a surface of the vibrating portion of the plurality of piezoelectric devices. An electrode that extends in the longitudinal direction of the vibrating portion and that is not in contact with each other is provided on one of the two piezoelectric devices, and one of the electrodes on the surface of the two piezoelectric devices among the plurality of piezoelectric devices is an electrode that connects to the outside; A piezoelectric device characterized in that the remaining electrodes on the surface of the piezoelectric device are connected between the piezoelectric devices without duplication or omission, and a capacitive element is connected between the electrode connected between the piezoelectric devices and the ground.