JPH06112759A - Piezoelectric resonator and piezoelectric filter - Google Patents

Abstract

PURPOSE:To attain the application of a resonator at the kHz bands and to ensure the characteristic of a wider band by securing such a constitution where a resonance part resonates by receiving the vibrations of a piezoelectric resonance unit via a vibration transmission part. CONSTITUTION:A vibration transmission part 1b is connected to a piezoelectric resonance unit 1a, and a resonance part 1c is connected to the part 1b. One of both ends of a coupling bar 1d is connected to the part 1c and a holding part 1e is connected to the other end of the bar 1d. The part 1b transmits the vibrations of the unit 1a to the part 1c. Thus the part 1c resonates by the vibrations received via the part 1b. In such a constitution, the part 1c resonates in a proper vibration mode like a flection mode, etc., and then eliminates the receive vibrations by the resonance. Thus it is possible to effectively prevent the vibrations from leaking out to the parts 1d and 1e which are connected to the outside of the part 1c.

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 and a piezoelectric filter configured so that vibration energy of a piezoelectric resonance portion is confined in the piezoelectric resonator.

[0002]

2. Description of the Related Art Conventionally, as a piezoelectric resonator in the kHz band, a resonator utilizing a spreading vibration mode of a rectangular plate-shaped piezoelectric plate, and a length mode vibration in which a rod-shaped piezoelectric member expands and contracts in the length direction are used. A resonator used, a piezoelectric tuning fork type resonator, or the like is used.

By the way, a piezoelectric resonator vibrates when a voltage is applied to its resonance portion. Therefore, when the piezoelectric resonator is constructed as an actual component, the piezoelectric resonance should not interfere with the resonance. You need to support your child. However, since the energy trapping type piezoelectric resonator traps the vibrational energy of the resonance portion, it can be mechanically held in a region other than the resonance portion. Therefore, in consideration of application to products, the energy trapping type piezoelectric resonator is easier to use, so that the energy trapping type resonator is also required for the piezoelectric resonator in the kHz band.

[0004]

However, it is impossible to confine the vibration energy in the resonator using the spreading vibration mode and the resonator using the length vibration mode which are known as general kHz band piezoelectric resonators. Met. Therefore, as shown in FIG. 2A, in the piezoelectric resonator 91 utilizing the length vibration mode, a structure in which the piezoelectric resonator 91 is held by sandwiching the node point of vibration between the spring terminals 92 and 93 is adopted. Was there. Similarly, even in a rectangular plate-shaped piezoelectric resonator using the spreading vibration mode, energy confinement was impossible, so the node point of the resonator was changed to
A structure in which it is held by being sandwiched by spring terminals has been adopted. Therefore, in the piezoelectric resonator and the piezoelectric filter using the spread vibration mode and the length vibration mode in the kHz band, the structure of the parts is complicated, and it is very difficult to configure them as a small chip type part that can be surface-mounted. It was

On the other hand, as shown in FIG. 2B, slits 94a to 94c are formed in the piezoelectric plate 94 polarized in the thickness direction.
And a vibrating electrode 95a (the back side is not shown) formed on both main surfaces around the central slit 94b, energy is trapped in the vibrating portion. Therefore, for example, the edge 94 of the piezoelectric plate 94
Even if held in the vicinity of d and 94e, the characteristics do not change, so that it can be configured as a surface mountable chip component.

However, although the piezoelectric tuning-fork type resonator 96 can confine energy, due to its mode restriction, the bandwidth can be secured only at about 2% of the resonance frequency. On the other hand, in the market, there is a strong demand for a piezoelectric resonator having a wide band 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 and a piezoelectric filter which can be used in the kHz band and can obtain a wider band characteristic.

[0008]

According to a first aspect of the present invention, there is provided a piezoelectric resonance unit, a vibration transmission part having one end connected to the piezoelectric resonance unit, and a vibration transmission part connected to the vibration transmission part. A resonance unit configured to resonate by receiving the vibration of the resonance unit; a connection bar having one end connected to the resonance unit; and a holding unit connected to the other end of the connection bar. It is a piezoelectric resonator.

According to a second aspect of the present invention, the first and second piezoelectric resonance units, a connecting member connecting the vibration node points of the first and second piezoelectric resonance units, and a connecting member. The first and second vibration resonance units connected to the surfaces of the first and second piezoelectric resonance units connected to each other on the opposite side to the connection member, and are connected to the respective vibration transmission units, Further, a resonance part configured to resonate by receiving the vibration leaked from the piezoelectric resonance unit, a connecting bar having one end connected to each resonance part, and a holding part connected to the other end of each connection bar. And an input / output electrode is formed on one surface of the first and second piezoelectric resonance units,
This is a piezoelectric filter in which a ground electrode is formed on the other main surface of the first and second piezoelectric resonance units so as to face the input / output electrodes from the front and back.

[0010]

In the piezoelectric resonator of the present invention, the vibration in the piezoelectric resonance unit is transmitted to the resonance section via the vibration transmission section. The resonating unit is configured to resonate with the vibration propagating through the vibration transmitting unit. Therefore, as is clear from the examples described below, the transmitted vibration is almost transmitted to the outside of the resonance part, that is, the coupling bar and the holding part, probably because the displacement vector in the vibration transmission part cancels the displacement vector in the resonance part. Instead, it operates as if the vibration energy was confined to the part up to the resonance part. Therefore, when the holding portion is used to fix the substrate or the case material, the vibration of the piezoelectric resonance unit is hardly affected by the fixing.

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

Further, in the piezoelectric filter according to the present invention as defined in claim 2, the filter is constituted by a plurality of resonance portions constituted by the first and second piezoelectric resonance units, and the piezoelectric resonance unit is provided outside the respective piezoelectric resonance units. The vibration that leaks to the resonator is transmitted to the resonance unit via the vibration transmission unit. Each of the resonance units is configured to resonate with the vibration propagating through the vibration transmission unit.

Therefore, similarly to the case of the invention described in claim 1, it is possible to trap the vibration energy leaked to the portion up to the resonance portion. Therefore, it is possible to fix the piezoelectric filter to the substrate or the case material by using the holding portion without hindering the operation of the piezoelectric filter.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram schematically showing a piezoelectric resonator of the present invention. In the piezoelectric resonator of the present invention, the vibration transmitting unit 1b is connected to the piezoelectric resonant unit 1a, and the resonance unit 1c is connected to the vibration transmitting unit 1b. One end of the connecting bar 1d is connected to the resonance part 1c, and the holding part 1e is connected to the other end of the connecting bar 1d.

The piezoelectric resonance unit 1a is constructed so that it can be excited in an appropriate vibration mode such as a length vibration mode, a contour sliding vibration mode, a spreading vibration mode, and a width vibration mode, as will be apparent from the embodiments described later. ing. The vibration transmission unit 1b is provided to transmit the vibration propagating from the piezoelectric resonance unit 1a to the resonance unit 1c.
Therefore, the structure of the vibration transmitting portion 1b is not particularly limited as long as it supports the piezoelectric resonance unit 1a and can transmit the vibration to the resonance portion 1c.

Further, the resonance section 1c is constructed so as to resonate upon receiving the vibration propagating through the vibration transmission section 1b. The resonance portion 1c is configured to resonate in an appropriate vibration mode such as a bending mode, and acts to cancel the propagated vibration by resonance, as shown in Experimental Examples and Examples described later.

The connecting bar 1d is provided to connect the resonance portion 1c and the holding portion 1e, and the holding portion 1e is
It is provided for fixing the piezoelectric resonator of the present invention to a case material or a substrate.

In the energy trap type piezoelectric resonator of the present invention, the propagating vibration is canceled by the resonance portion 1c, whereby leakage of the vibration to the outside of the device is prevented or suppressed. The leakage or suppression of the vibration due to such a resonance part was discovered by chance by the experiments of the inventors of the present application. 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 erected on the upper surface of the vibration tester 3.
A steel rod 5 capable of vibrating in a bending mode is fixed at an intermediate height position of the support rod 4. Steel rod 5 is 180m long
It is a rod-shaped member made of steel with m × width 12 mm × thickness 15 mm, the weight thereof is 240 g, and the resonance frequency at the time of bending is about 1 kHz. On the other hand, the support rod 4 has a diameter of 8
The steel rod 5 is a cylindrical member made of mm steel.
Is inserted into a through hole provided in the center of the steel rod, and the steel rod 5 and the support rod 4 are fixed in the illustrated state.
Therefore, the vibration tester 3 corresponds to the piezoelectric resonance unit of the present invention, the steel rod 5 corresponds to the resonance portion, and the portion of the support rod 4 below the steel rod 5 corresponds to the vibration transmission portion.

When the vibration tester 3 was vibrated vertically at a frequency of 1 kHz as shown by the arrow in the figure, the steel rod 5
Resonated in the bending mode, and the displacement amount 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 providing the steel rod 5 and the vibration tester 3 was similarly vibrated, the displacement amount of the upper end 4a of the support rod 4 was as shown in the figure. 5, the displacement amount ΔA in the figure was about 22.6 μm.

As is clear from the comparison of FIGS. 4 and 5,
It can be seen that the vibration transmitted from the vibration tester 3 through the support rod 4 is sufficiently damped in the steel rod 5 portion by providing the steel rod 5.

Incidentally, the inventors of the present application thought that the vibration was damped by the mass of the steel rod 5, and changed the frequency of the vibration to be applied, and conducted an experiment without causing the steel rod to resonate. It was confirmed that the displacement amount at the upper end 4a of No. 4 was not suppressed as shown in FIG. That is, as is apparent from this, the propagating vibration is not simply damped by the weight of the steel rod 5, but the propagating vibration is canceled by the steel rod 5 as described above. it is conceivable that.

As described above, the vibration tester 3 which is the 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 tester 3, the propagated vibration is canceled in the resonator. That is, in the piezoelectric resonator of the present invention, the propagated vibration is canceled by the resonance portion, so that the vibration energy of the piezoelectric resonance unit can be confined in the device.

Next, concrete examples will be described to clarify the present invention. Piezoelectric Resonator of Embodiment Utilizing Length Vibration Mode FIGS. 6A and 6B are plan views showing the piezoelectric resonator according to the first embodiment of the present invention and electrodes on the lower surface through the piezoelectric substrate. It is the top view which showed the shape. The piezoelectric resonator 21 has a piezoelectric resonance unit 22 arranged in the center. The piezoelectric resonance unit 22 has a structure in which electrodes 22a and 22b are formed on both main surfaces of a piezoelectric ceramic substrate having a rectangular elongated 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 a and 22b.

At the central portion in the length direction of the piezoelectric resonance unit 22, the vibration transmission portion 23 is connected to one side.
The vibration transmission unit 23 is provided to transmit the vibration associated with the stretching vibration of the piezoelectric resonance unit 22 to the resonance unit 24 described later. In addition, the vibration transmission unit 23 is the piezoelectric resonance unit 22.
The reason why the piezoelectric resonance unit 22 is connected to the central portion in the longitudinal direction is to prevent the vibration of the piezoelectric resonance unit 22 as much as possible.

A resonance portion 24 configured to resonate in a bending mode is connected to the other end of the vibration transmission portion 23. A holding portion 26 having a relatively large area is connected to the resonance portion 24 via a connecting bar 25. The holding portion 26 is configured to have a relatively large area as illustrated 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 the terminal electrode 28a formed on the upper surface of the holding portion 26 by the connecting conductive portion 27a. Even on the side opposite to the side to which the vibration transmission unit 23 is connected, the vibration transmission unit 29, the resonance unit 30, the connecting bar 31, and the holding unit 3 are attached to the piezoelectric resonance unit 22.
2 are connected and configured in the same manner as the side of the vibration transmitting section 23. Of course, as shown in FIG. 6B, the connection conductive portion 27b and the terminal electrode 28b electrically connected to the electrode 22b respectively include the vibration transmission portion 29 and the resonance portion 3 respectively.
0, the connecting bar 31, and the holding portion 32 are formed on the lower surface side.

The piezoelectric resonance unit 22, the first,
The second vibration transmitting portions 23 and 29, the resonance portions 24 and 30, the connecting bars 25 and 31, and the holding portions 26 and 32 may be integrally formed, for example, by processing one ceramic plate into the shape shown. Alternatively, they may all be formed as separate members and combined as shown to be integrated. Further, the vibration transmitting portion 23 and the connecting bar 25 are formed of one rigid member, and the resonance portion 2 is formed in the middle thereof.
4 may be connected so as to extend in at least one of the up and down directions in the drawing. In this case, the vibration transmitting part 23, the connecting bar 25, and the resonance part 24 may be made of different materials. As described above, the “connection” between the members in the present invention is not always used to mean connecting different members, but is simply used to define the positional relationship between a plurality of members. It is pointed out that it is a thing.

In the piezoelectric resonator 21 of this embodiment, by applying an AC voltage 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 transmission units 23 and 29.
Is transmitted to the resonance units 24 and 30 via the. As described with reference to FIGS. 7 and 8, the vibration hardly leaks to the connecting bars 25 and 31 side, probably because the displacement vector in the vibration transmitting unit and the displacement vector in the resonant unit cancel each other. Therefore, since the vibration energy is confined in the parts up to the resonance parts 24 and 30, when the holding parts 26 and 32 are mechanically fixed to the outside, the energy confinement type using the length vibration mode is used. The piezoelectric resonator 21 can be realized.

It should be noted that it is preferable that the resonance parts 24, 30 are provided.
The resonance frequency of is equal to the resonance frequency of the piezoelectric resonance unit 22. This is because, by matching the resonance frequency with the resonance frequency of the piezoelectric resonance unit 22, the displacement vectors are more effectively canceled out.

As described above, it is possible to confine the energy based on the resonance of the piezoelectric resonance unit by connecting the resonance units 24 and 30 to the piezoelectric resonance unit 22 via the vibration transmission units 23 and 29. It was discovered by chance from these experiments that the resonance part 24,
It is considered that the vibration propagated by 30 can be confined by the following mechanism.

As the mechanism capable of confining the vibration propagated as described above, there are two possible mechanisms described with reference to FIGS. 7 and 8 below. That is, FIG. 6 (a)
As is apparent from the above, for example, the resonance part 24 is connected to the outside of the vibration transmission part 23. The resonance part 24 has a pair of resonance parts by cantilever on both sides of the extended part of the vibration transmission part 23. It can be considered as a structure in which they are connected or a structure in which one resonance part 24 is interposed between the vibration transmission part 23 and the connection bar 25. FIG. 7 is a schematic enlarged plan view for explaining the action of the resonance part based on the former structure.
[FIG. 7] is a schematic enlarged plan view for explaining the action of the resonance part based on the latter structure.

First, it is considered that the pair of resonance portions are formed on both sides of the extended portion of the vibration transmission portion, and the operation of the resonance 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 and vibrates, the vibration transmitting portion 23a is moved to the reference numeral 23b by the transmitted vibration.
The state shown by and the state shown by the reference numeral 23c are deformed so as to be repeated.

By the way, the resonance portion 2 is provided in the vibration transmitting portion.
4a and 24b are connected, as shown in FIG. 7, the resonance parts 24a and 24b are connected to the vibration transmission part 23b,
With the deformation of 23c, it tilts and resonates as shown in the figure. As a result, the displacement vector in each of the tilted resonance parts 24a and 24b becomes the direction shown by the arrow A in the figure.

On the other hand, the X shown in the vibration transmitting portion 23b
The displacement vector in the axial direction is as shown by arrow B. Therefore, in any state, X in the resonance section 24
The displacement vector along the axial direction and the displacement vector along the X-axis direction in the vibration transmitting portion are in a canceling direction and balanced. Therefore, it is considered that the vibration energy propagating in the vibration transmission unit is canceled due to the resonance of the resonance units 24a and 24b, so that the vibration energy is trapped in the portions up to the resonance units 24a and 24b.

On the other hand, one resonance part 2 is provided at the other end of the vibration transmission part.
FIG. 8 shows a mechanism when it is considered that the central part of 4 is connected.
Will be described with reference to. 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 and vibrates, the vibration transmission section deforms by repeating the state indicated by reference numeral 23b and the state indicated by reference numeral 23c.

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

Incidentally, the piezoelectric resonator 2 of the embodiment shown in FIG.
In FIG. 1, one resonance part 24, 30 is arranged on each side of the piezoelectric resonance unit 22, but as shown in FIG. 9, a plurality of resonance parts 24, 24 are arranged on each side of the piezoelectric resonance unit 22. , 24, 30, 30, 30
May be arranged. In this case, the vibration transmission parts 23a and 23 are respectively provided between the plurality of resonance parts 24 and between the resonance parts 30.
It means that they are connected by b, 31a and 31b.

Piezoelectric resonance using contour sliding vibration mode
Embodiment of Child FIG. 10 is a perspective view showing an embodiment of a piezoelectric resonator using the contour sliding vibration mode. Piezoelectric resonator 51
Then, the piezoelectric resonance unit 52 utilizing the contour sliding vibration mode is arranged at the center. Piezoelectric resonance unit 52
In, a rectangular plate-shaped piezoelectric ceramic plate is uniformly polarized along a polarization direction P parallel to an excitation electrode described later.

In the piezoelectric resonance unit 52, electrodes 52a and 52b for excitation are formed on the upper surface and the lower surface of the piezoelectric resonance unit 52 shown in an upright state in FIG. The electrodes 52a and 52b are formed so as to reach the main surface of the piezoelectric resonance unit 52 on the illustrated side. Electrode 5
2a and 52b are arranged so as to face each other with the rectangular plate-shaped piezoelectric ceramic plate forming the piezoelectric resonance unit 52 interposed therebetween. Therefore, when an AC voltage is applied between the electrodes 52a and 52b, FIG. It vibrates so that the state shown by the alternate long and short dash line and the state shown by the broken line are repeated.

On the other hand, the vibration transmitting portion 53 is connected to the central portion of one side surface of the piezoelectric resonance unit 52. The resonance part 54 is connected to the other end of the vibration transmission part 53, the connection bar 55 is connected to the center of the outer side surface of the resonance part 54, and the holding part 56 is connected to the other end of the connection bar 55. Electrode 52a
Is the vibration transmission part 53, the resonance part 54 and the connecting bar 55.
The connection conductive portion 57a formed so as to pass through
It is electrically connected to a terminal electrode 58a formed on one surface of the holding portion 56.

Similarly, also on the other side of the piezoelectric resonance unit 52, the vibration transmitting portion 59, the resonance portion 60, and the connecting bar 61.
And the holding part 62 is connected. Then, the holding portion 62
The terminal electrode 58b formed on one surface of the connecting conductive portion 5
It is electrically connected to the electrode 52a of the piezoelectric resonance unit 52 by 7b.

Also in the piezoelectric resonator 51 of this embodiment, when the piezoelectric resonance unit 52 is vibrated in the contour slip vibration mode, the vibration is confined to the resonance parts 54 and 60. This will be described with reference to FIGS. 12 and 13.

FIG. 12 is a schematic diagram for explaining the operation of the resonance part when it is considered that a pair of resonance parts are connected to each other by a cantilever on both sides of the extension part of the vibration transmission part 53.
Now, in the initial state, the vibration transmitting unit is 53a in FIG.
The state is as shown in. And the piezoelectric resonance unit 5
Vibration due to contour slipping vibration associated with 2 vibration (transverse wave)
Is transmitted, the vibration transmitting unit vibrates so as to repeat the states indicated by reference numerals 53b and 53c in FIG. In this case, the vibration transmitting portions 53b and 53c are connected to the resonance portion 54.
Assuming that a and 54b are connected by a cantilever, each of the resonance parts 54a and 54b has the vibration transmission parts 53b and 53b.
It tilts in the direction shown on c.

As a result, the inclined resonance parts 54a, 5a
The direction of the displacement vector in 4b is the direction shown by arrow A in the figure. On the other hand, in the vibration transmitting portions 53b and 53c, the displacement vector is in the direction shown by the arrow B in the figure. Therefore, in any of the states shown in FIG.
The displacement vector at 54b and the displacement vector in the extension distribution of the vibration transmitting portion (displacement vector indicated by arrow B) cancel each other out in the Y-axis direction. Therefore, the propagated vibration is canceled by the resonance of the resonance parts 54a and 54b.

On the other hand, as shown in FIG. 13, the vibration transmitting portion 53
Assuming that the resonance part 54 is connected to the other ends of the b and 53c, the resonance part 54 has a structure in which the vibration transmission part is deformed between a state indicated by reference numeral 53b and a state indicated by reference numeral 53c.
Incline as shown.

As a result, the displacement vector B in the extended portion of the vibration transmitting portions 53b and 53c in the resonance portion 54.
And the displacement vector A in the portion inside the resonance portion that protrudes laterally from the extended portion of the vibration transmission portion are in the directions canceling each other in the Y-axis direction. Therefore, the propagating vibration is canceled due to the resonance of the resonance unit 54,
It is considered that the leakage of vibration to the outside of the resonance section 54 can be effectively prevented.

As described above, even when the transverse wave propagates, the resonance portion 54 is so damped that the propagating vibration is damped by the balance of the displacement vector in the Y-axis direction.
Are believed to resonate.

For a piezoelectric resonator utilizing a spreading vibration mode
Example of with Figure 14 (a), (b) is a plan view showing the lower electrode watermark plan view and a piezoelectric plate of a piezoelectric resonator according to the third embodiment.

The third embodiment is a piezoelectric resonator utilizing the spreading vibration mode of a rectangular plate. The piezo-resonator 81 has a piezo-resonant unit 82 that utilizes a spreading vibration mode of a rectangular 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 rectangular plate-shaped piezoelectric ceramic plate, and the piezoelectric ceramic plate portion sandwiched between the electrodes 82a and 82b is uniform in the thickness direction. Is polarized.

The third embodiment is characterized in that the piezoelectric resonance unit 82 utilizing the spreading vibration mode is used as the piezoelectric resonance unit. In other respects, the piezoelectric resonance unit of the first embodiment is used. It is configured similarly to the child 21. Therefore, in the piezoelectric resonator 81 shown in FIG. 14, the portions corresponding to those of the piezoelectric resonator 21 of the first embodiment shown in FIG. 6 are designated by the corresponding 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 spreads and resonates in a vibration mode. And
Also in this embodiment, the vibration of the piezoelectric resonance unit 82 is
It 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 mode. Therefore, the transmitted vibration is canceled by the resonance of the resonance parts 24 and 30, and the vibration energy is confined to the parts up to the resonance parts 24 and 30.

In the piezoelectric resonator 81 shown in FIG. 14, the resonance parts 24 and 3 are provided on both sides of the piezoelectric resonance unit 82.
Although 0 is connected via the vibration transmission parts 23 and 29, in the drawing of the piezoelectric resonance unit 82, the resonance part that can resonate in the bending mode is similarly connected via the vibration transmission part in the vertical direction. Good.

As described above, in the piezoelectric resonator of the present invention,
A piezoelectric resonance unit capable of resonating in various vibration modes can be used as the piezoelectric resonance unit, and the resonance energy is reliably confined to the resonance area by connecting the resonance area via the vibration transmission area. You can Therefore, it is possible to obtain an energy trapping type piezoelectric resonator utilizing a vibration mode, which has conventionally been unable to trap vibration energy.

In the above-mentioned embodiment, the resonance part which resonates in the bending mode is shown as the resonance part.
Even if the resonance part that resonates in another vibration mode, such as a sliding vibration mode, is configured, the vibration energy can be confined to the part up to the resonance part as in the above-described embodiment.

Application Example FIG. 15 is a schematic perspective view showing an example in which the piezoelectric resonator of the first embodiment is constructed as a concrete component. That is, in the piezoelectric resonance component 85, the piezoelectric resonator 21 shown in FIG. 6 is configured as a component with leads. Piezoelectric resonator 21
Of the terminal electrode 28a formed on the upper surface of the one holding portion 26
The lead terminal 86a is joined to the holding portion 3
The lead terminal 86b is joined to the terminal electrode (not shown) formed on the lower surface of 2. Then, the lead terminal 86
The remaining portion of the a and 86b excluding the tip end side portion is covered with the exterior resin 87 as shown by the dashed line in the figure.
In addition, in the exterior resin 87, the piezoelectric resonance unit 22 is provided.
Also, a cavity is formed so as not to interfere with the vibration of the vibrating portions such as the resonance portions 24 and 30. The cavity is the piezoelectric resonator 21.
Can be formed by applying a wax to the vibrating part of (1), then covering it with a thermosetting exterior resin 87, and applying a heat treatment.

In addition, the piezoelectric resonator of the present invention may be mounted on a case substrate or the like and sealed to form a surface mountable chip type component. Embodiment of Piezoelectric Filter FIG. 16 is a view showing a dual mode piezoelectric filter as an embodiment according to the invention described in claim 2, and FIG.
Is a plan view of the piezoelectric filter, and (b) is a schematic plan view showing a lower electrode shape through a piezoelectric substrate.

The piezoelectric filter 91 has first and second piezoelectric resonance units 92 and 93 utilizing the length vibration mode. The piezoelectric resonance units 92, 93 are electrodes 92 for forming input / output electrodes on one main surface of a piezoelectric ceramic substrate having a rectangular planar shape that is uniformly polarized in the thickness direction.
a, 93a are formed, and electrodes 92b, 93b functioning as ground electrodes are formed on the lower surface.

First and second piezoelectric resonance units 92, 93
Are respectively excited in the length vibration mode, and the node points of the vibration are connected by the connecting member 94. Further, on the lower surface, the electrode 92b and the electrode 93b are connected to the connecting conductive portion 94a formed on the lower surface of the connecting member 94.
Are electrically connected to each other. Therefore, the electrode 9
By using 2a or 93a as an input electrode or an output electrode and using the lower electrodes 92b and 93b as a ground electrode, a dual mode piezoelectric filter utilizing a symmetric mode and an asymmetric mode is constructed.

By the way, in the piezoelectric filter 91 of this embodiment, the vibration transmitting portions 95 and 96 are provided outside the first piezoelectric resonance unit 92 and the second piezoelectric resonance unit 93, respectively.
Are connected. The vibration transmitting portions 95 and 96 are connected to the node points of vibration on the side opposite to the side where the connecting members 94 of the piezoelectric resonance units 92 and 93 are connected.

Further, at the outer ends of the vibration transmitting portions 95 and 96, the resonating portions 97 and 9 resonated in the bending mode, respectively.
8 are configured. The resonance parts 97, 98 are configured to resonate by receiving the vibration leaked from the piezoelectric resonance units 92, 93, and act as a dynamic vibration absorption part for canceling the vibration leaked by the dynamic vibration absorption phenomenon. is there.

Retaining portions 101 and 102 having a relatively large area are connected to the outer ends of the resonance portions 97 and 98 via connecting bars 99 and 100. Holding parts 101, 10
2 is connected as a portion for fixing the piezoelectric filter 91 to the substrate or the case material.

The electrode 92a of the piezoelectric resonance unit 92 is also included.
Is electrically connected to the terminal electrode 101a formed on the upper surface of the first holding member 101 through the connection conductive portion 103, while the electrode 93a of the piezoelectric resonance unit 93 is connected to the terminal electrode 101a.
Are electrically connected to the terminal electrodes 102 a formed on the upper surface of the second holding member 102 via the connection conductive portions 104.

On the lower surface of the piezoelectric filter 91, the ground electrodes 92b and 93b are connected to the terminal electrodes 101b and 102b formed on the lower surfaces of the first and second holding members 101 and 102, respectively, and the connection conductive portion 105 is provided. , 106 are electrically connected.

Therefore, by connecting the terminal electrodes 101a and 102a to the input / output electrodes and connecting the terminal electrode 101b and / or the terminal electrode 102b to the ground potential, the piezoelectric filter 91 operates as a dual mode piezoelectric filter.

As apparent from FIG. 16, the connecting conductive portions 103, 1 formed on the upper surface side of the piezoelectric filter 91.
04, and the connecting conductive portions 105 and 106 formed on the lower surface side.
Are formed so that they do not face each other. Similarly, the terminal electrodes 101a and 102a are also formed at positions not facing the terminal electrodes 101b and 102b on the lower surface side. This is to prevent the stray capacitance from occurring by avoiding the overlapping of these electrodes.

The piezoelectric filter 91 of this embodiment operates as a dual mode piezoelectric filter as described above, but in this case, the piezoelectric resonance units 92 and 93 are vibrated. At this time, since the vibration transmitting portions 95 and 96 are connected to the vibration node points of the piezoelectric resonance units 92 and 93,
No vibration of a large vibration energy leaks to the vibration transmitting portions 95 and 96 side. However, with respect to the leaked vibration, the resonance parts 97 and 98 act as a dynamic vibration absorption part in the dynamic vibration absorption phenomenon, so that the resonance part 9
It is possible to reliably prevent the leakage of vibrations to the members outside the resonance portions 97 and 98, which are consumed by the resonance of the vibration elements 7 and 98.

Therefore, since the vibrations are confined to the parts up to the resonance parts 97 and 98, when the holding parts 101 and 102 are used to fix the parts to the case substrate or the like, the piezoelectric resonance unit 9 is used.
The piezoelectric filter 91 can be mechanically held without interfering with the vibrations of the second and the third motors 93.

The piezoelectric filter 91 of this embodiment can also be constructed as a chip-type electronic component, like the piezoelectric resonator shown in FIG. 6, or the electronic component with leads shown in FIG. Can be configured as.

Further, the piezoelectric resonance units 92 and 93 are not limited to those utilizing the length vibration mode as described above, and piezoelectric resonance units which resonate in other vibration modes such as the sliding vibration mode may be used. .

[0071]

According to the invention described in claim 1, since the resonance portion is connected to the piezoelectric resonance unit through the vibration transmission portion, the vibration propagated through the vibration transmission portion is generated in the resonance portion. It is canceled due to resonance. Therefore, it is possible to effectively prevent the leakage of vibration to the connecting bar and the holding part connected to the outside of the resonance part. In other words, the vibration energy is confined in the part up to the resonance part.

Therefore, if the holding member is used to join and fix the case member, the lead terminal, and the like, it is conventionally thought that it is impossible to construct an energy trap type piezoelectric resonator. The unit can be used to form an energy trap type piezoelectric resonator. Therefore, if the piezoelectric resonator of the present invention is configured by using the piezoelectric resonance unit that uses the length vibration mode or the spread vibration mode of the rectangular plate, the energy trap type piezoelectric resonance that can be used in the kHz band or several MHz band. It is possible to provide a piezoelectric resonator that is a child and has a wide band.

Also, in the invention described in claim 2,
Since the vibration transmission part and the resonance part are connected to the outside of the first and second piezoelectric resonance units, the vibration leaked through the vibration transmission part is canceled by the resonance in the resonance part. Therefore, it is possible to reliably prevent the vibration from leaking to the connecting bar and the holding part connected to the outside of the resonance part.

Therefore, when the holding portion is used to join and fix to the case material or the lead terminal, the piezoelectric filter can exhibit desired characteristics without disturbing the vibration of the first and second piezoelectric resonance units. Is possible.

Therefore, if the piezoelectric filter according to claim 2 is constructed by using the piezoelectric resonance unit utilizing the length vibration mode, the spread vibration mode of the rectangular plate, or the slip vibration mode, in the kHz band or a few MHz band. It becomes possible to provide a piezoelectric filter that can be used.

[Brief description of drawings]

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

2A and 2B are a perspective view and a plan view showing a piezoelectric resonator and a piezoelectric tuning-fork type resonator, respectively, which utilize a conventional length vibration mode.

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

FIG. 4 is a diagram showing a relationship between a displacement amount and time in the test apparatus shown in FIG.

FIG. 5 is a diagram showing a relationship between a displacement amount and time when a resonator is not provided.

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

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

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

FIG. 9 is a plan view showing a modification of the piezoelectric resonator component of the first embodiment and showing a structure in which a plurality of resonance parts are arranged.

FIG. 10 is a perspective view showing a piezoelectric resonator according to a second embodiment.

FIG. 11 is a schematic plan view for explaining a displacement state of the piezoelectric resonance unit used in the second embodiment.

FIG. 12 is a schematic diagram for explaining one mechanism of the action of the resonance section in the second embodiment.

FIG. 13 is a schematic diagram for explaining another mechanism of the operation of the resonance section in the second embodiment.

14A and 14B are respectively a plan view of a piezoelectric resonator according to a third embodiment and a plan view showing a lower electrode shape seen through a piezoelectric plate.

FIG. 15 is a schematic perspective view showing an example in which the piezoelectric resonator of the first embodiment is configured as a leaded piezoelectric resonance component.

16 (a) and 16 (b) are a plan view of a dual mode piezoelectric filter as an embodiment of the invention described in claim 2 and a schematic plan view showing a lower electrode shape through a piezoelectric plate.

[Explanation of symbols]

 1a ... Piezoelectric resonance unit 1b ... Vibration transmission part 1c ... Resonance part 1d ... Connection bar 1e ... Holding part

Claims (2)

[Claims] 1. A piezoelectric resonance unit, a vibration transmission unit having one end connected to the piezoelectric resonance unit, and a vibration transmission unit connected to the vibration transmission unit and configured to resonate by receiving vibration of the piezoelectric resonance unit. A piezoelectric resonator, comprising: a resonance part, a connection bar having one end connected to the resonance part, and a holding part connected to the other end of the connection bar. 2. A first and second piezoelectric resonance unit, a connecting member connecting the node points of vibration of the first and second piezoelectric resonance units, and a first and a second connecting members. Leakage from the piezoelectric resonance unit, which is connected to the first and second vibration transmission units respectively connected to the surface of the second piezoelectric resonance unit opposite to the connection member, and to each of the vibration transmission units. A resonance part configured to resonate by receiving the vibration, a connection bar having one end connected to each resonance part, and a holding part connected to the other end of each connection bar, Input / output electrodes are formed on one surface of the first and second piezoelectric resonance units, and ground electrodes are formed on the other main surfaces of the first and second piezoelectric resonance units so as to face the input / output electrodes. Is a piezoelectric filter.