JP3139145B2 - Piezoelectric resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonator, and more particularly, to a piezoelectric resonator configured so that vibration energy of a piezoelectric resonance portion is confined in the piezoelectric resonator.

[0002]

2. Description of the Related Art Heretofore, as a piezoelectric resonator in the kHz band, a resonator utilizing a spreading vibration mode of a square plate-like piezoelectric plate, and a length mode vibration which expands and contracts in the length direction of a rod-like piezoelectric body have been used. The used resonator or the piezoelectric tuning fork resonator is used.

[0003] Since a piezoelectric resonator vibrates when a voltage is applied to a resonance portion thereof, when the piezoelectric resonator is configured as an actual component, the piezoelectric resonator is so designed as not to hinder resonance. You need to support your child. However, in the energy-trap type piezoelectric resonator, the vibration energy of the resonance portion is confined, so that it is possible to mechanically retain the vibration energy in a region other than the resonance portion. Therefore, in consideration of application to a product, an energy trapping type piezoelectric resonator is easier to use, and therefore, an energy trapping type resonator is also required for a kHz-band piezoelectric resonator.

[0004]

However, it is impossible to confine vibration energy in a resonator using a spread vibration mode or a resonator using a length vibration mode, which is known as a general kHz-band piezoelectric resonator. Met. Therefore, as shown in FIG. 2A, in the piezoelectric resonator 91 using the length vibration mode, a structure is adopted in which the vibration resonance node 91 is held between the spring terminals 92 and 93 to hold the piezoelectric resonator 91. I was Similarly, in a square plate-shaped piezoelectric resonator using the expansion vibration mode, energy cannot be confined.
A structure of sandwiching and holding by a spring terminal has been adopted. Therefore, in the case of a piezoelectric resonator using a spreading vibration mode or a length vibration mode in the kHz band, the component structure is complicated, and it has been extremely difficult to configure a small chip-type component that can be surface-mounted.

On the other hand, as shown in FIG. 2B, slits 94a to 94c are formed in a piezoelectric plate 94 polarized in the thickness direction.
In the piezoelectric tuning fork resonator 96 in which the vibrating electrodes 95a (the back side is not shown) are formed on both main surfaces around the central slit 94b, energy is confined in the vibrating portion. Therefore, for example, the edge 94 of the piezoelectric plate 94
Even if held near d and 94e, the characteristics do not fluctuate, so that a chip component that can be surface-mounted can be configured.

However, in the piezoelectric tuning fork resonator 96, energy can be confined, but due to mode restrictions, a bandwidth of only about 2% of the resonance frequency can be secured. On the other hand, in the market, there is a strong demand for a broadband piezoelectric resonator even in the kHz band, and the piezoelectric tuning fork resonator 96 cannot meet such a demand.

An object of the present invention is to provide an energy-trap type piezoelectric resonator that can be used in the kHz band and can obtain wider band characteristics.

[0008]

According to the present invention, there is provided a piezoelectric resonance unit having a piezoelectric body and a plurality of excitation electrodes formed on the piezoelectric body, the piezoelectric resonance unit being excited in a predetermined vibration mode, and one end having the piezoelectric resonance unit. a vibration transmitting portion connected to the resonant unit, the vibrating
A rectangular plate extending in the direction intersecting with the direction in which the transmission section extends
Shaped, said being connected to the vibration transmitting portion in a portion other than the node points of the vibration of the vibration transmitting portion when vibrated by the vibration propagating from the piezoelectric resonant unit, and has been propagated from the piezoelectric resonator unit To cancel the vibration
At a resonance frequency substantially equal to the frequency of the vibration.
And a resonance unit that resonates in a mode .
It is a piezoelectric resonator.

[0009]

According to the piezoelectric resonator of the present invention, the vibration in the piezoelectric resonance unit is transmitted to the resonance unit via the vibration transmission unit. The resonance unit is connected to a portion other than the node point of the vibration transmission unit, and resonates at a frequency substantially equal to the resonance frequency of the piezoelectric resonance unit by the vibration propagated via the vibration transmission unit. It is configured as follows. Therefore, as is apparent from the examples described later, because the displacement vector in the vibration transmission unit cancels the displacement vector in the resonance unit, the propagated vibration is hardly transmitted outside the resonance unit, and it is as if to the resonance unit. It operates in such a state that vibration energy is confined in the part.

Therefore, by adopting an appropriate structure such as a piezoelectric resonance unit using the length vibration mode or a piezoelectric resonance unit using the expansion vibration mode of the square plate as the piezoelectric resonance unit, the kHz band or several MHz is adopted. It is possible to realize a wide-band energy trap type piezoelectric resonator that can be used in a band.

[0011]

Figure 1 [Description of Embodiment] is a block diagram schematically showing a piezoelectric resonator of the present invention. In the piezoelectric resonator of the present invention, the vibration transmission unit 1b is connected to the piezoelectric resonance unit 1a. Further, the resonance section 1 c is connected to a node Ten以 outside portion of the vibration transmitting portion 1b.

The piezoelectric resonance unit 1a is configured so as to be able to be excited in an appropriate vibration mode such as a length vibration mode and a spread vibration mode, as will be apparent from embodiments described later. Further, the vibration transmitting unit 1b includes a piezoelectric resonance unit 1a.
It is provided to transmit the vibration propagated from the to the resonance unit 1c . Accordingly, the structure itself of the vibration transmission unit 1b as long as it can transmit vibrations to support the piezoelectric resonator unit 1a, and the resonance part 1 c, are not particularly limited.

The resonating section 1c is configured to resonate upon receiving the vibration propagated via the vibration transmitting section 1b. The resonating portion 1c is configured to resonate at the bending vibration mode, as shown in Experimental Examples and Examples below, by resonance, it acts to cancel the vibration propagated. In the energy trap type piezoelectric resonator of the present invention, the transmitted vibration is generated by the resonance portion 1c.
It is counteracted, thereby preventing or suppressing the leakage of the vibration out of the device. Leakage or suppression of vibration due to such resonance part are those Desa seen Ri by the experiments of the present inventors. Hereinafter, a more specific description will be given with reference to FIGS.

FIG. 3 is a front sectional view showing an experimental apparatus for clarifying the principle of the present invention. Referring to FIG.
A support rod 4 is provided upright on the upper surface of the vibration testing machine 3.
A steel rod 5 capable of vibrating in a bending vibration mode is fixed at an intermediate height position of the support rod 4. The steel bar 5 has a length of 18
It is a rod-shaped member made of steel having a size of 0 mm x 12 mm x 15 mm, weighs 240 g, and has a resonance frequency of about 1 kHz when bent. On the other hand, the support rod 4 is a columnar member made of steel having a diameter of 8 mm, is inserted into a through hole provided at the center of the steel rod 5, and the steel rod 5 and the support rod 4 are shown in the drawing. The state is fixed. Therefore, the vibration testing machine 3 corresponds to the piezoelectric resonance unit of the present invention, the steel bar 5 corresponds to the resonance unit, and the portion of the support rod 4 below the steel bar 5 corresponds to the vibration transmission unit.

When the vibration tester 3 was vibrated at a frequency of 1 kHz in the vertical direction as shown by the arrow in the figure, the steel rod 5
Resonated in the bending vibration mode, and the amount of displacement of the upper end 4a of the support rod 4 was as shown in FIG. In FIG. 4, the amount of displacement ΔB was about 2.6 μm. For comparison, when the support rod 4 was erected on the vibration tester 3 without the steel bar 5 and the vibration tester 3 was similarly vibrated, the displacement of the upper end 4a of the support rod 4 was As shown in FIG.
The displacement ΔA in the figure was about 22.6 μm.

As is clear from the comparison between FIGS. 4 and 5,
It can be seen that the vibration transmitted from the vibration tester 3 via the support rod 4 is sufficiently attenuated at the steel rod 5 by providing the steel rod 5. The inventors of the present application also considered that the vibration was damped by the mass of the steel rod 5 and changed the frequency of the applied vibration and performed an experiment without causing the steel rod to resonate. It was confirmed that the displacement amount in 4a was not suppressed as shown in FIG. That is, as is apparent from this, the transmitted vibration is not simply damped by the weight of the steel rod 5, but the transmitted vibration is canceled by the steel rod 5 as described above. it is conceivable that.

As described above, the vibration tester 3 as a vibration source
On the other hand, since the steel rod 5, that is, the resonator is connected via the support rod 4 arranged to receive the vibration of the vibration testing machine 3, the transmitted vibration is canceled in the resonator. That is, in the piezoelectric resonator according to the present invention, the transmitted vibration is canceled by the resonance unit, so that the vibration energy of the piezoelectric resonance unit can be confined in the device. Next, the operation of the resonance unit will be described based on a more specific embodiment, thereby clarifying the present invention.

The piezoelectric resonator of the embodiment using the length vibration mode
FIGS. 6A and 6B are a plan view showing a piezoelectric resonator according to the first embodiment of the present invention and a plan view showing the shape of an electrode on a lower surface through a piezoelectric substrate. The piezoelectric resonator 21 has a piezoelectric resonance unit 22 disposed at the center. The piezoelectric resonance unit 22 has a structure in which electrodes 22a and 22b are formed on both main surfaces of a rectangular piezoelectric ceramic substrate having a slender planar shape that is uniformly polarized in the thickness direction. Electrode 22
The piezoelectric resonance unit 22 is configured to expand and contract in a length vibration mode by applying an AC voltage from the terminals a and 22b.

At the center in the length direction of the piezoelectric resonance unit 22, a vibration transmitting section 23 is connected to one side.
The vibration transmission unit 23 is provided to transmit vibration accompanying expansion and contraction vibration of the piezoelectric resonance unit 22 to a resonance unit 24 described below. Further, the vibration transmission unit 23 is
Is connected to the central portion in the length direction in order to prevent the vibration of the piezoelectric resonance unit 22 as much as possible.

The other end of the vibration transmitting section 23 has a frequency substantially equal to the resonance frequency of the piezoelectric resonance unit 22 and a bending vibration.
A resonating unit 24 configured to resonate in a dynamic mode is connected. Note that the other end of the vibration transmitting unit 23 is in an area other than the node point when the vibration transmitting unit 23 vibrates due to the vibration from the piezoelectric resonance unit 22. Also, the resonance unit 24
Is connected to a holding portion 26 having a relatively large area via a connection bar 25. The holding portion 26 is configured to have a relatively large area as shown in the drawing so as to be suitable for mechanically holding the piezoelectric resonator 21 on another member such as a case substrate.

The electrode 22a is electrically connected to a terminal electrode 28a formed on the upper surface of the holding section 26 by a connection conductive section 27a. Also on the side opposite to the side to which the vibration transmitting unit 23 is connected, the vibration transmitting unit 29, the resonance unit 30, the connection bar 31, and the holding unit 3 are attached to the piezoelectric resonance unit 22.
2 are connected to each other, and have the same configuration as the vibration transmission unit 23 side. However, as shown in FIG. 6B, the connection conductive portion 27b and the terminal electrode 28b electrically connected to the electrode 22b are respectively connected to the vibration transmission portion 29 and the resonance portion 3
0, the connecting bar 31 and the holding portion 32 are formed on the lower surface side.

In the piezoelectric resonator 21 of this embodiment, when an AC voltage is applied between the terminal electrodes 28a and 28b, the piezoelectric resonance unit 22 expands and contracts in the length vibration mode. As a result, the vibration is transmitted to the vibration transmitting units 23 and 29.
Is transmitted to the resonance units 24 and 30 via the. Then, as described with reference to FIGS. 7 and 8, the vibration hardly leaks to the connection bars 25 and 31 because the displacement vector in the vibration transmission unit and the displacement vector in the resonance unit cancel each other. Therefore, the vibration energy is confined in the portion up to the resonance parts 24 and 30. Therefore, when mechanically fixed to the outside using the holding parts 26 and 32, the energy confinement type using the length vibration mode is used. The piezoelectric resonator 21 can be realized.

As described above, by connecting the resonance units 24 and 30 to the piezoelectric resonance unit 22 via the vibration transmitting units 23 and 29, it is possible to confine energy based on the resonance of the piezoelectric resonance unit. It was discovered by accident by these experiments that the resonance part 24,
The following mechanism is considered to be able to confine the vibration transmitted by 30.

As mechanisms capable of confining the vibrations propagated as described above, there are two types of mechanisms described with reference to FIGS. That is, FIG.
As is clear from FIG. 3A, for example, the resonance unit 24 is connected to the outside of the vibration transmission unit 23.
Is a structure in which a pair of resonating sections are connected by cantilever beams on both sides of a portion where the vibration transmitting section 23 is extended, or the vibration transmitting section 2
This is considered to be a structure in which one resonating portion 24 is interposed between 3 and the connecting bar 25. FIG. 7 is a schematic enlarged plan view for explaining the operation of the resonance unit based on the former structure, and FIG. 8 is a schematic enlarged view for explaining the operation of the resonance unit based on the latter structure. It is an enlarged plan view.

First, it is assumed that a pair of resonating portions are formed on both sides of a portion where the vibration transmitting portion is extended, and the operation of the resonating portions will be described with reference to FIG. Now, it is assumed that there is a vibration transmitting portion 23a connected to the piezoelectric resonance unit. In this case, when the piezoelectric resonance unit expands and contracts, the transmitted vibration causes the vibration transmitting unit 23a to generate the reference numeral 23b.
And a state indicated by reference numeral 23c is repeated.

By the way, the vibration transmitting section is connected to the resonance section 2.
Assuming that the vibration transmitting parts 23a, 24b are connected to each other, the resonance parts 24a, 24b are connected to the vibration transmitting parts 23b, 23b, as shown in FIG.
As shown in the figure, it resonates and resonates with the deformation of 23c. As a result, the displacement vector in each of the inclined resonance parts 24a and 24b becomes the direction shown by the arrow A in the figure.

On the other hand, X in the vibration transmitting portion 23b shown in FIG.
The displacement vector in the axial direction is as shown by arrow B. Therefore, in any state, X
The displacement vector along the axial direction and the displacement vector along the X-axis direction of the vibration transmitting unit are in a direction in which they cancel each other. Therefore, it is considered that the vibration transmitted through the vibration transmitting unit is canceled by the resonance of the resonance units 24a and 24b, so that the vibration energy is confined to the portions up to the resonance units 24a and 24b.

On the other hand, one resonance section 2 is connected to the other end of the vibration transmission section.
FIG. 8 shows a mechanism in a case where the central portion of
This will be described with reference to FIG. Now, it is assumed that there is a vibration transmitting portion 23a connected to the piezoelectric resonance unit. In this case, when the piezoelectric resonance unit expands and contracts, the transmitted vibration causes the vibration transmission unit to deform so as to repeat the state indicated by reference numeral 23b and the state indicated by reference numeral 23c.

The other end of the vibration transmitting section is connected to the resonance section 2.
In the case where 4 is connected at the center, as shown in FIG. 8, the resonating unit 24 bends and vibrates as shown in FIG. As a result, the displacement vector in the resonance section 24 is as shown in the figure. That is, as in the case shown in FIG. 7, the displacement vector B in the portion where the vibration transmitting portions 23b and 23c are extended and the displacement vector A in the remaining portion of the resonance portion 24 cancel each other out in the X-axis direction. balance. Therefore, it is considered that the vibration propagating through the vibration transmitting unit is canceled with the resonance of the resonance unit 24, so that the vibration energy is confined to the portion up to the resonance unit 24.

The above two types of vibration energy confinement mechanisms are based on estimation, but in any case, as shown in FIG. The vibration transmitted through the transmission unit 23 is canceled by the resonance unit 24, thereby confining the vibration energy. The operation of the resonance unit 24 will be described based on specific experimental results.

FIG. 9 shows a structure prepared for comparison. The piezoelectric resonance unit 35 is configured to be capable of vibrating in the length vibration mode at one side center thereof in a direction perpendicular to the piezoelectric resonance unit 35. An extending bar 36 is connected. The bar 36 is similarly connected to the center of the other side surface.

On the other hand, FIG. 10 has a structure in which a resonance section 37 is provided in the structure shown in FIG. That is, FIG.
In the structure of FIG.
And a bar 39 is connected to the surface of the resonance unit 37 opposite to the side to which the vibration transmission unit 38 is connected. In other words, the vibration transmission unit 3
8 and the bar 39, the resonance portion 37
Corresponds to the structure formed with. In the structure of FIG. 10,
The same structure as described above is connected to the other side surface of the piezoelectric resonance unit 35.

When the piezoelectric resonance unit 35 is vibrated in the length vibration mode in the piezoelectric resonator shown in FIG. 9, the displacement distribution is as shown in FIG. the absolute value of the displacement amount V _x in the X-axis direction at each portion is as shown in FIG. 11 (b).

On the other hand, the displacement distribution of vibration when the piezoelectric resonance unit 35 is resonated in the piezoelectric resonator shown in FIG. 10 is as shown in FIG. FIG.
The absolute value V of the amount of displacement in the X-axis direction at each part on the X-axis
_x was as shown in FIG. FIG.
As apparent from a comparison between FIG. 12B and FIG.
It can be seen that the provision of the resonating portion 37 causes the bar 39 ahead of the resonating portion 37 to have a very small displacement due to the transmitted vibration. In other words, it can be understood that the vibration energy can be confined in the portion up to the resonance section 37.

As described above, it can be seen that the vibration propagated by the action of the resonating portion is canceled. In the present invention, the resonating portion is connected to a portion other than the node of the vibration transmitting portion. For this reason, the transmitted vibration is more effectively canceled by the resonance unit. This will be described with reference to FIGS. When the piezoelectric resonance unit 35 resonates in the structure shown in FIG.
The vibration leaks to the bar 36. In this case, the bar 36
Are as shown in an enlarged manner in FIG. That is, the bar 36 is displaced as shown in FIG. 13 by the propagated vibration (high wave) (arrows in FIG. 13 indicate displacement vectors).

As is apparent from FIG. 13, the bar 36 has a portion that is largely displaced and a portion that is hardly displaced, that is, a node point, due to the transmitted vibration. That is, the relative scale in the X-axis direction shown in the upper part of FIG.
It can be seen that there is almost no displacement in the part. Therefore, in the piezoelectric resonator shown in FIG. 10, the operation of the resonance unit 37 was confirmed by changing the distance P, that is, the distance between the side surface of the piezoelectric resonance unit 35 and the center of the resonance unit 37.

FIGS. 14 to 17 show the distance P, respectively.
Are set to 0.5, 1.0, 1.5, 2.0,... And the absolute value of the displacement amount in the X-axis direction at each portion along the X-axis direction. As is clear from FIG. 16, the distance P = 1.5
In the case of, it can be seen that a considerable amount of vibration is propagated outside the resonating portion. This is the distance P = 1.5
When the resonance unit is connected to the position, that is, the node point,
This means that the vibration cannot be canceled sufficiently by resonance. In contrast, in FIG. 14 (when the distance P = 0.5), FIG. 15 (when the distance P = 1.0), and FIG. It can be seen that the leakage of the vibrations is very small. Therefore, in the present invention, it is preferable that the resonating portion is connected to a portion other than the node point of the vibration transmitting portion, so that the vibration propagated by the resonating portion can be effectively canceled.

As is apparent from a comparison between FIG. 11B and FIG. 16, even when the resonance section 37 is connected to the node point, FIG. In comparison with the piezoelectric resonator, the suppression of leakage of vibration to the outside can be achieved. In addition, in the piezoelectric resonator 21 of the embodiment shown in FIG.
Although the holding portions 26 and 32 are connected via 31, this is merely provided for facilitating mechanical fixing at the time of commercialization. That is, as shown in FIG. 18, connecting portions 40a and 40b for connecting with other portions are formed on the side of the resonance portions 24 and 30 opposite to the side where the vibration transmitting portions 23 and 29 are connected. In other words, as in the case of the embodiment shown in FIG. 6, the vibration energy can be confined in the portion up to the resonance portions 24 and 30. Therefore, as in the embodiment shown in FIG. Can be used as

The piezoelectric resonator 2 of the embodiment shown in FIG.
In FIG. 1, one resonating portion 24, 30 is disposed on each side of the piezoelectric resonance unit 22. However, as shown in FIG. , 24,30,30,30
May be arranged. In this case, the vibration transmitting parts 23a and 23a
b, 29 a, so that it is attached in 29 b.

For a piezoelectric resonator utilizing a spreading vibration mode
Example of with Figure 20 (a), (b) is a plan view showing the lower electrode watermark plan view and a piezoelectric plate of a piezoelectric resonator according to the second embodiment. The second embodiment is a piezoelectric resonator using a spread vibration mode of a square plate. Piezoelectric resonator 81
Has a piezoelectric resonance unit 82 utilizing a spread vibration mode of a square plate. The piezoelectric resonance unit 82 has a structure in which electrodes 82a and 82b are formed on the entire surfaces of both main surfaces of a square plate-shaped piezoelectric ceramic plate, and a portion of the piezoelectric ceramic plate sandwiched between the electrodes 82a and 82b is one in the thickness direction. It is polarized.

The second embodiment is characterized in that the above-described piezoelectric resonance unit 82 utilizing a spreading vibration mode is used as the piezoelectric resonance unit. In other respects, the piezoelectric resonance unit 82 of the first embodiment is used. It is configured similarly to the child 21. Therefore, in the piezoelectric resonator 81 shown in FIG. 20, portions corresponding to those of the piezoelectric resonator 21 of the first embodiment shown in FIG. 6 are given the same reference numerals, and the description thereof will be omitted. .

In the piezoelectric resonator 81, the terminal electrodes 28a, 2
By applying an AC voltage between 8b, the piezoelectric resonance unit 82 vibrates in the expansion vibration mode. And
Also in this embodiment, the vibration of the piezoelectric resonance unit 82 is
The vibration is transmitted to the resonance units 24 and 30 via the vibration transmission units 23 and 29, and the resonance units 24 and 30 resonate in the bending vibration mode at substantially the same frequency as the resonance frequency of the piezoelectric resonance unit. Therefore, the transmitted vibration is canceled by the resonance of the resonance units 24 and 30, and the vibration energy is reduced to the resonance unit 2.
It is trapped in up to 4,30 parts.

In the piezo-resonator 81 shown in FIG.
0 is connected via the vibration transmitting units 23 and 29, but also in the vertical direction in the drawing of the piezoelectric resonance unit 82, a resonating unit capable of resonating in a bending vibration mode is similarly connected via the vibration transmitting unit. You may.

As described above, in the piezoelectric resonator of the present invention,
As the piezoelectric resonance unit, a piezoelectric resonance unit that can resonate in various vibration modes can be used, and by connecting the resonance unit via the vibration transmission unit, the vibration energy is reliably confined to the portion up to the resonance unit. Can be. Therefore, it is possible to obtain an energy-trapping type piezoelectric resonator utilizing a vibration mode in which vibration energy cannot be confined conventionally.

[0045]

[0046]

According to the present invention, since the above-mentioned resonating portion is connected to a portion other than the node point of the vibration transmitting portion, the vibration propagated via the vibration transmitting portion is caused by the resonance in the resonating portion. Effectively countered. Therefore, it is possible to effectively prevent the vibration from leaking to a portion connected to the outside of the resonance portion. In other words, the vibration energy is confined to the portion up to the resonance section.

Therefore, an energy trapping type piezoelectric resonator can be constituted by using a vibration mode piezoelectric resonance unit which has conventionally been considered impossible to construct an energy trapping type piezoelectric resonator. Therefore, if the piezoelectric resonator of the present invention is configured using a piezoelectric resonance unit utilizing a length vibration mode or a square plate expansion vibration mode, an energy trapping type piezoelectric resonance that can be used in a kHz band or a few MHz band is used. It is possible to provide a piezoelectric resonator that is a child and has a wide band.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a configuration of the present invention.

FIGS. 2A and 2B are a perspective view and a plan view, respectively, showing a piezoelectric resonator and a piezoelectric tuning fork resonator using a conventional length vibration mode.

FIG. 3 is a front sectional view showing a test apparatus for explaining the principle of the present invention.

FIG. 4 is a diagram illustrating a relationship between a displacement amount and time in the test apparatus illustrated in FIG. 3;

FIG. 5 is a diagram showing a relationship between a displacement amount and time when no resonator is provided.

FIGS. 6A and 6B are a plan view of the piezoelectric resonator of the first embodiment and a schematic plan view showing a lower electrode shape through a piezoelectric plate, respectively.

FIG. 7 is a schematic diagram for explaining one possible mechanism of the operation of the resonance unit in the first embodiment.

FIG. 8 is a schematic diagram for explaining another mechanism of the operation of the resonance unit in the first embodiment.

FIG. 9 is a plan view showing a structure in which a bar is connected to a piezoelectric resonance unit using a length vibration mode.

FIG. 10 is a plan view having a structure in which a resonance unit is connected to a piezoelectric resonance unit using a length vibration mode.

11A and 11B are diagrams showing a displacement distribution in the structure shown in FIG. 9 and a diagram showing an absolute value of a displacement amount in each portion along the X-axis direction, respectively.

12A and 12B are a diagram showing a displacement distribution in the structure shown in FIG. 10 and a diagram showing an absolute value of a displacement amount in each portion along the X-axis direction, respectively.

FIG. 13 is a diagram showing a displacement state of a vibration transmission unit in the structure shown in FIG.

FIG. 14 is a diagram showing the absolute value of the displacement amount in the X-axis direction at each portion along the X-axis direction when the distance P = 0.5 in FIG. 10;

FIG. 15 is a diagram showing the absolute value of the displacement amount in the X-axis direction at each portion along the X-axis direction when the distance P = 1.0 in FIG. 10;

FIG. 16 is a diagram showing the absolute value of the displacement amount in the X-axis direction in each part along the X-axis direction when the distance P = 1.5 in FIG. 10 (in the case of a node point).

FIG. 17 is a diagram showing the absolute value of the displacement amount in the X-axis direction at each portion along the X-axis direction when the distance P in FIG. 10 is 2.0.

FIG. 18 is a plan view showing a modified example of the piezoelectric resonator of the first embodiment.

[Figure 19] shows another modification of the piezoelectric resonator of the first embodiment, a plan view showing a plurality of resonator units are arranged structure.

FIGS. 20A and 20B are a plan view of the piezoelectric resonator of the second embodiment and a plan view showing the shape of the lower electrode seen through the piezoelectric plate, respectively.

[Explanation of symbols]

1a ... piezoelectric resonant unit 1b ... vibration transmitting portion 1 c ... resonator portion

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-207614 (JP, A) JP-A-1-241210 (JP, A) JP-A 1-222913 (JP, A) JP-A-55- 121728 (JP, A) JP-A-55-85120 (JP, A) JP-A-54-51498 (JP, A) JP-A-4-49707 (JP, A) JP-A-3-284007 (JP, A) JP-A-3-265209 (JP, A) JP-A-3-108810 (JP, A) JP-B-45-36780 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H03H 9/00-9/215

Claims (1)

(57) [Claims] 1. A piezoelectric resonance unit having a piezoelectric body, a plurality of excitation electrodes formed on the piezoelectric body, and excited in a predetermined vibration mode, and a vibration transmission one end of which is connected to the piezoelectric resonance unit. Part, and a rectangle extending in a direction intersecting with a direction in which the vibration transmitting part extends.
It has a shape of a plate, is connected to the vibration transmitting unit at a portion other than a node point of vibration of the vibration transmitting unit when vibrated by vibration propagated from the piezoelectric resonance unit, and the piezoelectric resonance unit so as to cancel out the vibration that has been propagated from, shake
In the bending vibration mode at a resonance frequency approximately equal to the frequency of the motion
A piezoelectric resonator comprising: a resonance unit that resonates.