JPH07336184A - Energy confining type piezoelectric resonator - Google Patents

Abstract

PURPOSE:To obtain an energy confining type piezoelectric resonator utilizing a thickness mode, in which energy confining efficiency is improved and resonance characteristics are satisfactory. CONSTITUTION:The piezoelectric resonator of an energy confining type 1 respectively forms first and second resonance electrodes 3 and 4 on the top 2a and the bottom 2b of a rectangular piezoelectric board 2 which is uniformly polarize- processed in the direction of thickness. On the other hand, the resonator is provided with dynamic vibration absorbing parts 9 and 10 by fixing other members to the outside of resonance areas where the first and second resonance electrodes 3 and 4 oppose each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy trapping type piezoelectric resonator using a thickness mode, and more particularly to an energy trapping type piezoelectric resonance provided with a structure capable of effectively trapping vibration energy in a resonance region and its vicinity. Regarding the child.

[0002]

2. Description of the Related Art Various energy trapping type piezoelectric resonators utilizing thickness modes such as a thickness longitudinal vibration mode and a thickness shear vibration mode have been conventionally known. In the energy trap type piezoelectric resonator utilizing the thickness mode, for example, the resonance electrodes are formed on both main surfaces of the piezoelectric plate, and the resonance electrodes formed on both main surfaces are arranged so as to overlap each other via the piezoelectric plate. ing. Further, the resonance electrodes formed on both main surfaces are formed to be narrower than the surface on which the resonance electrodes are formed, so that the resonance region where the resonance electrodes on both main surfaces are overlapped is piezoelectric. The vibration energy is confined in a region narrower than the main surface of the plate.

In the energy trap type piezoelectric resonator, by limiting the resonance region to be narrower than the area of the piezoelectric plate,
Since it is possible to mechanically hold the piezoelectric resonator outside the resonance region, it is widely used in various resonance components and bandpass filters.

[0004]

In the conventional energy trapping type piezoelectric resonator utilizing the thickness mode, the resonance energy is confined by narrowing the resonance region narrower than the surface on which the electrode of the piezoelectric body is formed. Has been done. However, the confinement of this vibrational energy is
It was not perfect so that no vibration leaked out of the resonance region, and some vibration had to leak out of the resonance region.

Therefore, when the piezoelectric resonator is mechanically held outside the resonance region, the resonance characteristic may be affected. It is an object of the present invention to provide an energy trapping type piezoelectric resonator utilizing a thickness mode which is more excellent in energy trapping efficiency and therefore can exhibit excellent resonance characteristics.

[0006]

The present invention is characterized in that an energy trapping type piezoelectric resonator utilizing a thickness mode has a higher energy trapping efficiency by utilizing a dynamic vibration absorption phenomenon.

That is, the energy trap type piezoelectric resonator of the present invention has a piezoelectric body having first and second surfaces facing each other, and a direction connecting the first and second surfaces is a thickness direction. A first resonance electrode and a second resonance electrode which are partially formed on the first and second surfaces and overlap each other in the thickness direction via a piezoelectric body.
An energy trap type piezoelectric resonator utilizing a thickness mode in which a region where the first and second resonant electrodes overlap is a resonant region, and the resonant region is provided on at least one of the first and second faces. It is further characterized by further comprising a dynamic vibration absorbing portion provided outside the.

As described above, the present invention relates to an energy trap type piezoelectric resonator utilizing the thickness mode. Examples of the thickness mode include various conventionally known thickness modes such as a thickness longitudinal mode and a thickness sliding mode.

Further, the energy trap type piezoelectric resonator of the present invention is constituted by using a piezoelectric body having first and second surfaces facing each other. The piezoelectric body used is lead zirconate titanate. It is also possible to use a piezoelectric single crystal such as LiTaO ₃ or LiNbO ₃ or a crystal in addition to a ceramic such as a system piezoelectric ceramic.

In the present invention, the resonance region is formed by forming the resonance electrodes on the first and second surfaces of the piezoelectric body which face each other, and thereby the thickness mode vibration energy is confined in the resonance region. Up to this point, it is the same as the conventional energy trap type piezoelectric resonator using the thickness mode.

In the present invention, the dynamic vibration absorbing portion is further provided in order to enhance the energy trapping efficiency.
The dynamic vibration absorbing portion is a portion that acts to suppress the vibration transmitted by the dynamic vibration absorbing phenomenon. For details of this dynamic vibration absorbing phenomenon, see, for example, Osamu Taniguchi, "Vibration Engineering," pages 113 to 11.
It is described on page 6 (published by Corona). To put it simply, the dynamic vibration absorption phenomenon means that the vibration of the main vibrating body is determined by connecting the sub vibrating body to the main vibrating body whose vibration is to be prevented and appropriately selecting the natural frequency of the sub vibrating body. It is a phenomenon that is suppressed. The dynamic vibration absorbing portion of the piezoelectric resonator of the present invention corresponds to a sub-vibration body in the dynamic vibration absorbing phenomenon, and the propagated vibration is suppressed by the dynamic vibration absorbing portion based on the dynamic vibration absorbing phenomenon.

In the present invention, the dynamic vibration absorbing portion is provided outside the resonance region on at least one of the first and second surfaces of the piezoelectric body, and thereby the vibration propagated from the resonance region is moved. It is possible to suppress it by the vibration absorption phenomenon.

In a certain limited aspect of the present invention, the dynamic vibration absorbing portion is composed of a dynamic vibration absorbing member fixed to at least one of the first and second surfaces of the piezoelectric body. It is not necessary to use a piezoelectric material as a material forming such a dynamic vibration absorbing member, and an appropriate material can be used.
However, in order to damp the vibration propagated by the dynamic vibration absorption phenomenon, the dynamic vibration absorption member is made of a material that can exhibit a natural frequency equal to or close to the frequency of the propagated vibration. Preferably. However, since the natural frequency of the dynamic vibration absorbing part differs not only by the material but also by the shape of the dynamic vibration absorbing part, it is possible to suppress the vibration transmitted as described above by devising the shape of the dynamic vibration absorbing part. As long as it is possible to use an appropriate material.

Further, in the present invention, preferably, the dynamic vibration absorbing member is made of the same material as that of the first and second resonance electrodes. That is, by forming the dynamic vibration absorbing member with the same material as the electrode material, the dynamic vibration absorbing portion can be formed at the same time in the electrode forming step.

Further, according to the present invention, there is provided an energy trap type piezoelectric resonator having the above-mentioned resonance region. In the resonance region, a first resonance electrode is formed with a predetermined gap, and third and fourth resonances are formed. The piezoelectric filter may be divided into electrode parts, and thereby the third resonant electrode part and the fourth resonant electrode part may serve as input / output ends.

Further, in order to form a dual mode piezoelectric filter, two resonance regions are formed in the piezoelectric body, and
The dynamic vibration absorbing portion may be provided between the individual resonance regions.

[0017]

In the energy trapping type piezoelectric resonator of the present invention, the energy trapping type resonance is achieved by partially forming the first and second resonance electrodes on the first and second surfaces of the piezoelectric body which face each other. The area is configured. Therefore, the vibration energy generated in the resonance region is substantially confined in the resonance region.

Further, in the present invention, the dynamic vibration absorbing portion is provided outside the resonance region. Therefore, the energy of vibration leaking from the resonance region is suppressed by the dynamic vibration absorbing portion based on the dynamic vibration absorbing phenomenon. Therefore, in the energy trapping type piezoelectric resonator of the present invention, it is possible to trap the vibrational energy almost certainly up to the portion where the dynamic vibration absorbing portion is formed.

That is, the present invention is characterized in that the conventional energy trapping type piezoelectric resonator is further provided with a dynamic vibration absorbing portion to further enhance the energy trapping efficiency.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be clarified by describing embodiments with reference to the drawings.

FIG. 1 is a perspective view showing an energy trap type piezoelectric resonator according to a first embodiment of the present invention.
3 is a plan view of the piezoelectric resonator, and FIG. 3 is a front cross-sectional view.
The piezoelectric resonator 1 is an energy trap type piezoelectric resonator using a thickness extension mode. In the piezoelectric resonator 1, a piezoelectric plate 2 having a rectangular planar shape is used. In this embodiment,
The piezoelectric plate 2 is made of lead zirconate titanate-based piezoelectric ceramics, and is uniformly polarized in the direction of arrow P shown in the figure, that is, in the thickness direction of the piezoelectric plate 2.

A first resonance electrode 3 having a circular planar shape is formed in the center of the upper surface 2a of the piezoelectric plate 2. On the lower surface 2b of the piezoelectric plate 2, a second resonance electrode 4 having a circular planar shape is formed so as to face the first resonance electrode 3 on the front and back sides. When an AC voltage is applied between the first and second resonance electrodes 3 and 4, the region where the first and second resonance electrodes 3 and 4 overlap, that is, the resonance region is vibrated in the thickness longitudinal vibration mode. It The resonance region is limited to a part of the main surface of the piezoelectric plate 2. Therefore, as in the conventional energy trap type piezoelectric resonator, the vibration energy is substantially trapped in the resonance region.

The first resonance electrode 3 has a pair of connection conductive portions 5
It is electrically connected to the terminal electrode 6 via a and 5b. The terminal electrode 6 is formed along the one edge on the upper surface 2a of the piezoelectric plate 2 and is used for electrical connection with the outside. Similarly, also on the lower surface 2b of the piezoelectric plate 2, so as to be electrically connected to the second resonance electrode 4,
A pair of connection conductive portions 7a and 7b are formed. The second resonance electrode 4 is electrically connected to the second terminal electrode 8 via the connection conductive portions 7a and 7b.

The first and second resonance electrodes 3 and 4, the connection conductive portions 5a, 5b, 7a and 7b and the first and second terminal electrodes 6 and 8 are provided on the upper surface 2a and the lower surface 2b of the piezoelectric plate 2. It can be formed by forming a conductive film on the entire surface by a thin film forming method such as vapor deposition, sputtering or plating, and then patterning. However, the electrode structures on the upper surface 2a and the lower surface 2b of the piezoelectric plate 2 can be formed by screen-printing a conductive paste and curing it, for example.

The first and second resonance electrodes 3 and 4, the connection conductive portions 5a, 5b, 7a and 7b, and the terminal electrodes 6 and 8 may be formed of the same material through the same process as described above. It may be formed through another process. Also, the first
The second resonance electrodes 3 and 4, the connection conductive portions 5a, 5b, 7a,
The conductive material forming 7b and the terminal electrodes 6 and 8 is not particularly limited, and an appropriate material such as Cu, Ag, Al or an alloy thereof can be used.

In the piezoelectric resonator 1 of this embodiment, annular dynamic vibration absorbing portions 9 and 10 are provided on the upper surface 2a and the lower surface 2b of the piezoelectric plate 2 outside the resonance region, respectively. The dynamic vibration absorbing portions 9 and 10 are configured by printing an insulating paste-like material such as resin or glass on the upper surface 2a and the lower surface 2b of the piezoelectric plate 2 in a ring shape.

The dimensions and materials of the dynamic vibration absorbing parts 9 and 10 are selected so that the natural frequency of the dynamic vibration absorbing parts 9 and 10 matches the frequency of the vibration leaking from the resonance region.
By selecting as described above, it is possible to suppress the leaked vibration in the dynamic vibration absorbing units 9 and 10 based on the dynamic vibration absorbing phenomenon. Therefore, in the piezoelectric resonator 1 according to the present embodiment, the vibration energy is trapped in the energy trap type resonance portion, and the vibration that leaks slightly is the dynamic vibration absorbing portion 9 provided outside the resonance region. It is suppressed by 10. Therefore, as compared with the conventional energy trap type piezoelectric resonator, the trapping efficiency of vibration energy can be effectively increased.

Therefore, the portions where the first and second terminal electrodes 6 and 8 are formed are used for external connection, and the regions where the terminal electrodes 6 and 8 are formed are used to mechanically hold them. Even if it does, the resonance characteristics in the resonance region are unlikely to be affected. Therefore, it is possible to provide an energy trap type piezoelectric resonator having excellent characteristics.

FIG. 4 is a perspective view showing an energy trap type piezoelectric resonator according to a second embodiment of the present invention.
FIG. 4 is a front sectional view thereof. The piezoelectric resonator 21 is configured by using a piezoelectric plate 22 having an elongated rectangular plate shape, and is configured as an energy trap type piezoelectric resonator using a thickness shear vibration mode.

In this embodiment, the piezoelectric plate 22 is made of lead zirconate titanate-based piezoelectric ceramics having an elongated rectangular shape in plan view, and is polarized in the direction of arrow P shown in the figure, that is, in the direction parallel to its principal surface. Has been done. Piezoelectric plate 22
A first resonance electrode 23 is formed on the upper surface 22a of the piezoelectric element 22 so as to extend from the one end surface 22c to the center of the piezoelectric plate 22. Further, on the lower surface 22b of the piezoelectric plate 22, the second resonance electrode 24 is formed so as to extend from the end surface 22d to the central region of the piezoelectric plate.

The first and second resonance electrodes 23 and 24 are arranged so as to face each other in the central region of the piezoelectric plate 22, and the first and second resonance electrodes 23 and 24 face each other. The region constitutes a resonance region.

That is, the first and second resonance electrodes 23, 2
By applying an AC voltage between the four, the resonance region is excited in the thickness shear vibration mode. The vibration in this resonance region is configured such that the resonance region is limited to a partial region of the piezoelectric plate 22, so the vibration energy is substantially confined in the resonance region.

In the present embodiment, the dynamic vibration absorbing member 25 is located outside the resonance region, that is, on the upper surface 22a of the piezoelectric plate 22, between the resonance region and the end face 22c and between the resonance region and the end face 22d. , 26 are fixed. The dynamic vibration-damping members 25 and 26 have an elongated striped shape having a rectangular planar shape, and are configured to reach the entire width of the piezoelectric plate 22. However, the shapes of the dynamic vibration absorbing parts 25 and 26 are not limited to the shapes shown in FIG. 4, and can be appropriately changed as long as the vibration leaking from the resonance region can be suppressed by the dynamic vibration absorbing phenomenon. .

In this embodiment, the lower surface 2 of the piezoelectric plate 22 is
Also on 2b, the dynamic vibration absorbing parts 27,
28 is provided. The dynamic vibration absorbing parts 27 and 28 are also configured similarly to the dynamic vibration absorbing parts 25 and 26 on the upper surface 22a.

In the piezoelectric resonator 21 of this embodiment, the first and second resonance electrodes 23 and 24 are connected to the outside in regions outside the dynamic vibration absorbing parts 25 and 26 and outside the dynamic vibration absorbing parts 27 and 28. Like the piezoelectric resonator of the first embodiment, the dynamic vibration absorbing portions are electrically connected and mechanically held in a region outside the portions where the dynamic vibration absorbing portions 25 to 28 are provided. The vibration energy can be reliably confined up to the portion where is provided. Therefore, the energy trapping efficiency can be effectively increased as compared with the conventional energy trapping type piezoelectric resonator utilizing the thickness shear vibration mode.

FIG. 6 is a plan view of an energy trap type piezoelectric resonator according to a third embodiment of the present invention. The energy trap type piezoelectric resonator 31 of the third embodiment is configured by using the piezoelectric plate 2 having a rectangular planar shape. In this embodiment, energy utilizing the thickness longitudinal vibration mode of the rectangular piezoelectric plate 2 is used. It is a confinement type piezoelectric resonator. Therefore, basically, the piezoelectric resonator 31 of the third embodiment is configured similarly to the piezoelectric resonator 1 of the first embodiment. Therefore, the first
The same parts as those of the piezoelectric resonator 1 according to the embodiment are given the same reference numerals, and the description thereof will be omitted.

The third embodiment differs from the piezoelectric resonator 1 of the first embodiment in the structure of the dynamic vibration absorbing portion. That is, as shown in FIG. 6, in the piezoelectric resonator 31 of the present embodiment, the same material as that of the first resonance electrode 3 is used outside the resonance region where the first resonance electrode 3 is formed. The dynamic vibration absorbing parts 33 and 34 are formed. Dynamic vibration absorber 33,
Reference numeral 34 corresponds to a shape obtained by cutting a part of a ring surrounding the resonance electrode outside the resonance region. In other words, the dynamic vibration absorbing parts 33, 34 correspond to a shape obtained by dividing a part of the dynamic vibration absorbing part 9 of the first embodiment.

As described above, the dynamic vibration absorbing portions 33 and 34 are configured so as to have a shape in which the ring is divided, because the dynamic vibration absorbing portions 33 and 34 are made of the same material as the resonance electrode 3. Therefore, it is necessary to electrically insulate the resonance electrode 3.

Note that, as shown in the plan view of the lower electrode shape through the piezoelectric plate 32 in FIG. 7, even on the lower surface of the piezoelectric plate 32, the dynamic vibration absorbing parts 35,
36 is formed. The dynamic vibration absorbing parts 35 and 36 are configured similarly to the dynamic vibration absorbing parts 33 and 34 formed on the upper surface side.

In this embodiment, the dynamic vibration absorbing parts 33 to 36 are used.
However, since it is made of the same material as the first and second resonance electrodes 3, 4, etc., it can be formed in the same step as the first, second resonance electrodes 3, 4 and the terminal electrodes 6, 8. it can. Therefore, it is not necessary to separately perform a new process to form the dynamic vibration absorbing parts 33 to 36, and thus the dynamic vibration absorbing parts can be configured without lowering the productivity.

The dimensions and thickness of the dynamic vibration absorbing parts 33 to 36 are appropriately determined so that the vibration leaking from the resonance region can be suppressed by the dynamic vibration absorbing phenomenon. Figure 8
It is a typical top view for explaining the energy trap type piezoelectric resonator concerning the 4th example of the present invention. The energy trap type piezoelectric resonator 41 of the present embodiment is configured as a dual mode piezoelectric filter utilizing the thickness extensional vibration mode.

The piezoelectric resonator 41 is composed of a piezoelectric ceramic plate 42 having a rectangular planar shape.
In, two resonance regions A and B are formed at a predetermined distance.

In the first resonance region A, the piezoelectric plate 42
On the upper surface 42a of the third and fourth resonance electrode portions 43
a and 43b are formed at a predetermined distance. Third,
The fourth resonance electrode portions 43a and 43b are formed so as to overlap with the second resonance electrode 44 formed on the lower surface 42b of the piezoelectric plate 42. That is, the third and fourth resonance electrode portions 43a and 43b have a shape obtained by dividing the circle formed by projecting the second resonance electrode 44 formed on the lower surface upward. Is configured. Therefore, the third and fourth resonance electrode portions 43a and 43b
Corresponds to a structure in which the first resonance electrode 3 in the first embodiment is divided into two.

Similarly, in the resonance region B, the piezoelectric plate 4
The third and fourth resonance electrode portions 45a and 45b on the upper surface of 2.
The second resonance electrode 46 is formed on the lower surface of the piezoelectric plate 42. Further, on the upper surface of the piezoelectric plate 42, the piezoelectric plate 42
The first terminal electrode 47 is formed in the vicinity of one corner portion of the above, and the second terminal electrode 48 is formed in the other corner portion along the side surface 42c of the piezoelectric plate 42. In addition, the fourth resonance electrode portion 43b and the third resonance electrode portion 45a
And are electrically connected by a conductive pattern. First
The terminal electrode 47 of is electrically connected to the third resonance electrode portion 43a through the connection conductive portion 50. In addition, the fourth resonance electrode portion 45b in the resonance region B is connected to the second terminal electrode 48.
Electrically connected to. On the other hand, the second resonance electrode 4
4, 46 are electrically connected to the ground electrode 49 on the lower surface of the piezoelectric plate 42.

Therefore, in the piezoelectric resonator 41 of this embodiment,
The energy trapping type resonance part using two thickness longitudinal vibration modes is configured with a predetermined distance, and the first terminal electrode 47 serves as an input end and the second terminal electrode 48 serves as an output end. An energy trapping dual mode piezoelectric filter is constructed.

Further, in the piezoelectric resonator 41 of this embodiment,
Between the first and second resonance regions A and B, the piezoelectric plate 4
The dynamic vibration absorbing portion 53 is formed on the upper surface 42a of the second. Similar to the third embodiment, the dynamic vibration absorbing portion 53 is made of the same material as the electrode material for forming the resonance electrode and the like. That is, it is formed by forming a conductive film in a region outside each of the resonance regions A and B so as to have an elongated rectangular shape.

Therefore, also in the fourth embodiment, the dynamic vibration absorbing portion 53 can be simultaneously formed in the step of forming the resonance electrode and the like. However, the dynamic vibration absorbing portion 53 may be configured by fixing a material other than the electrode material, for example, an insulating resin or ceramics.

In the fourth embodiment, the dual mode piezoelectric filter provided with the two resonance regions A and B has been described as an example, but in one resonance region, the third and third resonance regions as described above are used. The present invention can be applied to a piezoelectric filter configured by forming the fourth resonance electrode portion on one surface of the piezoelectric plate so as to face the second resonance electrode.

Furthermore, in the first to third embodiments, the dynamic vibration absorbing portions are formed outside the first and second resonant electrodes on both main surfaces of the piezoelectric plate, respectively. It may be formed on only one of the first surface and the second surface of the piezoelectric plate.

Further, for example, in the piezoelectric resonator 21 of the second embodiment, the upper surface 22a and the lower surface 22b of the piezoelectric plate 22 are arranged.
In any of the above, the dynamic vibration absorbing parts 2 are provided on both sides of the resonance region.
5, 26 or the dynamic vibration absorbing portions 27, 28 are provided, the dynamic vibration absorbing portion may be provided only on one side. That is, in the structure shown in FIG. 4, among the dynamic vibration absorbing parts 25 to 28,
Any three or less dynamic vibration absorbers may be omitted.

However, in order to effectively suppress the vibration leaked from the resonance region by the dynamic vibration absorbing portion, it is preferable to arrange the dynamic vibration absorbing portions symmetrically on both sides of the resonance region. Further, in the present invention, more dynamic vibration absorbing parts shown in the above-mentioned embodiments may be arranged. For example, in FIG.
In, the dynamic vibration absorbing parts may be further provided outside the dynamic vibration absorbing parts 25 to 28 (on the side opposite to the resonance part). Also, FIG.
In, at least one ring-shaped dynamic vibration absorbing portion may be provided outside the dynamic vibration absorbing portion 9.

Further, in the first to fourth embodiments, the piezoelectric plates 2, 22, 42 having a relatively small thickness are used as the piezoelectric body, but the piezoelectric body in the present invention is not limited to the plate-like one. Alternatively, it is possible to use a block-shaped piezoelectric body,
In short, the direction in which the first and second surfaces on which the resonance electrode is formed is connected is the thickness direction, and the present invention is applied to an appropriate energy trap type piezoelectric resonator utilizing the thickness longitudinal mode or the thickness sliding mode. can do.

[0053]

According to the present invention, in the energy trap type piezoelectric resonator utilizing the thickness mode, first, the vibration energy is trapped in the resonance region where the first and second resonance electrodes overlap each other, and the resonance region A small amount of vibration leaked from the device is suppressed by the dynamic vibration absorbing portion provided outside the resonance region based on the dynamic vibration absorbing phenomenon.

Therefore, it is possible to obtain an energy trapping type piezoelectric resonator having a dramatically improved energy trapping efficiency as compared with the conventional energy trapping type piezoelectric resonator. Therefore, when the piezoelectric resonator is mechanically held outside the dynamic vibration absorbing part, the mechanical holding hardly affects the resonance characteristic, and thus the resonator having the good resonance characteristic can be provided.

Preferably, the dynamic vibration absorbing portion is made of the same material as the resonance electrode, so that the energy trapping type piezoelectric resonator excellent in the resonance characteristics as described above can be obtained without increasing the manufacturing process. You can

[Brief description of drawings]

FIG. 1 is a perspective view showing an energy trap type piezoelectric resonator according to a first embodiment of the present invention.

FIG. 2 is a plan view of the energy trap type piezoelectric resonator according to the first embodiment.

FIG. 3 is a front sectional view of the energy trap type piezoelectric resonator according to the first embodiment.

FIG. 4 is a perspective view showing an energy trap type piezoelectric resonator according to a second embodiment of the present invention.

FIG. 5 is a front sectional view of a piezoelectric resonator according to a second embodiment.

FIG. 6 is a plan view showing an energy trap type piezoelectric resonator according to a third embodiment of the present invention.

FIG. 7 is a schematic plan view showing a lower electrode shape through a piezoelectric plate in a third embodiment.

FIG. 8 is a piezoelectric resonator according to a fourth embodiment of the present invention,
The top view which shows the structure comprised as a dual mode piezoelectric filter.

FIG. 9 is a schematic plan view showing the electrode shape on the lower surface of the piezoelectric plate in the fourth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric resonator 2 ... Piezoelectric plate 2a ... Upper surface (first surface) 2b ... Lower surface (second surface) 3, 4 ... First and second resonant electrodes 9, 10 ... Dynamic vibration absorbing portion 21 ... Piezoelectric resonance Child 22 ... Piezoelectric plate 22a ... Upper surface (first surface) 22b ... Lower surface (second surface) 23, 24 ... First and second resonant electrodes 25-28 ... Dynamic vibration absorbing part 31 ... Piezoelectric resonator 32 ... Piezoelectric Plates 33 to 36 ... Dynamic vibration absorbing part 41 ... Piezoelectric resonator 42 ... Piezoelectric plate 42a ... Upper surface (first surface) 42b ... Lower surface (second surface) 43a, 43b, 45a, 45b ... Third and fourth resonances Electrodes 44, 46 ... Second resonance electrode 53 ... Dynamic vibration absorber

Claims (5)

[Claims] 1. A piezoelectric body having first and second surfaces facing each other, wherein a direction connecting the first and second surfaces is a thickness direction; and the first and second surfaces, Each of the first and second resonance electrodes is formed partially and overlaps with each other in the thickness direction through the piezoelectric body, and the overlapping region of the first and second resonance electrodes is resonated. The energy trap type piezoelectric resonator utilizing the thickness mode, which is defined as a region, further includes a dynamic vibration absorbing portion provided outside the resonance region on at least one of the first and second surfaces. Characteristic is an energy trapping type piezoelectric resonator. 2. The energy trap type piezoelectric resonator according to claim 1, wherein the dynamic vibration absorbing portion is constituted by a dynamic vibration absorbing member fixed to at least one of the first and second surfaces of the piezoelectric body. . 3. The energy trap type piezoelectric resonator according to claim 2, wherein the dynamic vibration absorbing member is made of the same material as that of the first and second resonant electrodes. 4. The first resonance electrode has a third resonance electrode portion and a fourth resonance electrode portion which are formed with a predetermined gap, and the third resonance electrode portion and the fourth resonance electrode portion are formed. The energy trap type piezoelectric resonator according to claim 1, wherein a piezoelectric filter having an electrode portion as an input / output end is configured. 5. The two resonance regions are formed in the piezoelectric body so as to form a dual mode filter, and the dynamic vibration absorbing portion is provided between the two resonance regions.
2. An energy trap type piezoelectric resonator according to claim 1.