JP2002164764A - Composite material vibrating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibrating device which does not have the restriction of a vibration mode to be utilized, does not need a vibration damping part, can be mechanically supported with a simple structure and can be miniaturized. SOLUTION: This composite material vibrating device is provided with a piezoelectric element 2 which is made of material having a first acoustic impedance value Z1 and functions as a vibration member to be a vibration generation source, first and second reflecting layers 3 and 4 which are made of material having acoustic impedance Z2 lower than the first acoustic impedance Z1 and connected to the both sides of the piezoelectric element 2, and first and second holding members 5 and 6 which are connected to the outer sides of the reflecting layers 3 and 4 and made of material having an acoustic impedance value Z3 larger than the second acoustic impedance Z2, and vibrations propagated from the piezoelectric element 2 are reflected at the interfaces between the reflecting layers 3 and 4, and the holding members 5 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite material vibration device having a structure capable of holding various vibration members without affecting the vibration of the vibration members. The present invention relates to a composite material vibration device using an element.

[0002]

2. Description of the Related Art Conventionally, piezoelectric vibrating parts have been widely used for resonators, filters, and the like. For example, in a piezoelectric resonator, various vibration modes are used to obtain a target resonance frequency. These vibration modes include thickness longitudinal vibration, thickness shear vibration, length vibration, width vibration, spreading vibration,
Or, bending vibration or the like is known.

In a piezoelectric resonator, the holding structure differs depending on the type of vibration mode. In the case where the thickness longitudinal vibration or the thickness shear vibration is used, an energy trap type piezoelectric resonator can be formed, so that the piezoelectric resonator can be mechanically held at the end of the piezoelectric resonator. FIG. 33 shows an example of this type of energy trap type piezoelectric resonator utilizing thickness shear vibration. In the piezoelectric resonator 201, a resonance electrode 203 is formed on an upper surface of a strip-shaped piezoelectric plate 202, and a resonance electrode 204 is formed on a lower surface of the piezoelectric plate 202 so as to face the resonance electrode 203. The resonance electrodes 203 and 204 are opposed to each other at the center in the longitudinal direction of the piezoelectric plate 202, and the opposed portions constitute an energy trapping type piezoelectric vibrating portion. Due to the energy confinement type, the vibration is almost confined in the piezoelectric vibrating part. Therefore,
The piezoelectric resonance electrode 201 can be mechanically held at the end without obstructing the vibration of the piezoelectric vibrating portion.

However, in the energy trapping type piezoelectric resonance electrode 201, although vibration energy is confined in the piezoelectric vibrating portion, a vibration damping portion having a relatively large area must be formed outside the piezoelectric vibrating portion. Therefore, for example, in the strip-shaped piezoelectric resonator 201 using the thickness shear mode, the length dimension has to be increased.

On the other hand, in a piezoelectric resonator utilizing length vibration, width vibration, spreading vibration or bending vibration, an energy trapping type piezoelectric resonance section cannot be formed. Therefore, in order not to affect the resonance characteristics, a holding structure is configured by using a metal terminal having a spring property and bringing the metal terminal into contact with a vibration node of the piezoelectric resonator.

On the other hand, Japanese Patent Laying-Open No. 10-270979 discloses a bulk acoustic wave filter 211 shown in FIG. In the bulk acoustic wave filter 211, the substrate 21
A filter is formed by laminating a plurality of films on the surface 2. That is, in this laminated structure, the piezoelectric layer 21
3 are formed, and electrodes 214 and 215 are laminated on the upper surface and the lower surface of the piezoelectric layer 213 to form a piezoelectric resonator. On the lower surface of the piezoelectric resonator, a film such as silicon or polysilicon is laminated to form an upper layer 21.
6, an acoustic mirror 219 having a laminated structure including a middle layer 217 and a lower layer 218 is formed. Here, the middle layer 217
Has a higher acoustic impedance than the acoustic impedance of the upper layer 216 and the lower layer 218. It is said that the acoustic mirror 219 blocks transmission of the vibration generated by the piezoelectric resonator to the substrate 212.

On the other hand, an acoustic mirror 220 having the same configuration is laminated above the piezoelectric resonator, and a passivation film 221 is formed on the acoustic mirror 220. The passivation film 221 is made of epoxy, SiO ₂
Alternatively, it is made of another suitable protective material.

[0008]

In a conventional energy trap type piezoelectric resonator, a vibration damping portion needs to be formed outside the piezoelectric vibrating portion, so that it can be mechanically held using an adhesive or the like. However, the size of the piezoelectric resonator 201 must be increased.

On the other hand, in a non-energy confinement type piezoelectric resonator utilizing a length vibration mode or a spread vibration mode,
Although the vibration damping section is not required, the resonance characteristics are impaired when the piezoelectric resonator itself is fixed and held using an adhesive or solder. Therefore, it is necessary to support using a spring terminal or the like, the supporting structure is complicated, and a large number of parts are required.

[0010] In the bulk acoustic wave filter described in Japanese Patent Application Laid-Open No. H10-270979, a plurality of films are stacked on the substrate 202 as described above so that the piezoelectric resonator and the piezoelectric resonator and the substrate are acoustically separated. An acoustic mirror 119 is provided to insulate the acoustic mirror. Therefore, the piezoelectric resonator is acoustically cut off and supported by the acoustic mirror 219 having a laminated structure with respect to the substrate 212.

However, in the bulk acoustic wave filter 211, a large number of layers are laminated on the substrate 212, and a lower acoustic mirror 219, a laminated structure forming a piezoelectric resonator or a piezoelectric filter, and an upper acoustic mirror 220 are formed. A large number of constituent layers had to be formed, and a passivation film 221 had to be formed at the top. Therefore, the structure is complicated, and the vibration mode of the piezoelectric resonator to be used is limited by the laminated structure.

As described above, conventionally, in order to support a vibration source such as a piezoelectric resonator without impairing its vibration characteristics,
There have been problems in that there are restrictions on the vibration mode, components become large, and the structure becomes complicated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art, and to support a vibration member in various modes with a relatively simple structure without substantially affecting the vibration characteristics of the vibration member. An object of the present invention is to provide a composite material vibration device having a possible structure.

[0014]

According to a broad aspect of the present invention, there is provided a composite vibrating device in which a plurality of material portions having different acoustic impedances are combined, the material having a _first acoustic impedance value Z1. A vibration member serving as a vibration generation source, and a first acoustic impedance value Z ₁
Made of a material having a second acoustic impedance Z ₂ is lower than, and the first which are connected to both sides of the vibration member, and a second reflective layer, a large first second than the acoustic impedance Z ₂ made of a material having a third acoustic impedance Z _3, wherein the first, to the side where the vibrating member of the second reflective layer is connected and a holding member connected to the opposite side, the said reflective layer There is provided a composite material vibration device configured to reflect vibration propagated from the vibration member to the reflection layer at an interface with a holding member.

In a specific aspect of the present invention, the first acoustic impedance value Z ₂ of the _second acoustic impedance value Z _2
The ratio Z ₂ / Z ₁ to ₁ is set to 0.2 or less, more preferably 0.1 or less.

[0016] In another specific aspect of the present invention, the second ratio Z ₂ / Z ₃ for the third acoustic impedance Z ₃ of the acoustic impedance Z ₂ is 0.2 or less, more preferably 0.1 or less I can take it.

In one limited aspect of the present invention, an electromechanical coupling conversion element is used as the vibration member, and in a more limited aspect, a piezoelectric element or an electrostrictive element is used as the electromechanical coupling conversion element.

According to another specific aspect of the present invention, a third reflection member is provided on a side of the first and / or second holding member opposite to a side where the first and second reflection layers are connected. The layer, the second vibration member, the fourth reflection layer, and the third holding member are connected in this order.

According to another broad aspect of the present invention, there is provided a composite material vibrating apparatus in which a plurality of material portions having different acoustic impedances are combined, comprising a material having a _first acoustic impedance value Z ₁ , First and second vibrating members serving as vibration sources, and a first acoustic impedance value Z
A reflective layer made of a material having a lower second acoustic impedance value Z ₂ than _1, the second acoustic impedance Z ₂
A holding member made of a material having a _third acoustic impedance Z3 larger than the first holding member, the first reflection layer, the first vibration member, the second vibration layer, the second vibration member, The third reflection layer and the second holding member are connected in this order, and each vibration generated by the first and second vibration members is transmitted to the first or third reflection layer by the first or second reflection member. The composite material vibration device is reflected by the interface with the holding member of the second reflection layer and the interface between the second reflection layer and the second vibration member or the first vibration member.

[0020] In another specific aspect of the present invention, the reflective layer is formed by laminating a plurality of material layers having different acoustic impedances. In another specific aspect of the present invention, when the wavelength of the vibration when the vibration member vibrates alone is λ, from the interface between the reflection layer and the vibration member to the interface between the reflection layer and the holding member. The distance is n · λ / 4 ±
It is configured to be in the range of λ / 8 (n is an odd number).

In the composite material vibration device according to the present invention, when the vibration displacement direction A of the vibration member, the vibration propagation direction B of the vibration member, and the vibration propagation direction C of the reflection layer, the direction A
About -C, it can be variously combined. For example, the directions A to C may be parallel to each other. Further, the direction A and the direction B may be parallel, and the direction B and the direction C may be in a relationship of being orthogonal. Further, the direction A and the direction B may be orthogonal, and the direction B and the direction C may be parallel. Further, the direction A and the direction B may be orthogonal, and the direction B and the direction C may be orthogonal.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by describing specific embodiments of the present invention with reference to the drawings.

FIGS. 1A and 1B are a perspective view and a longitudinal sectional view showing a piezoelectric resonator as a composite material vibration device according to an embodiment of the present invention. The piezoelectric resonator 1 includes a strip-shaped piezoelectric element 2 as a vibration member, reflection layers 3 and 4 connected to both ends of the piezoelectric element 2 in a longitudinal direction, and a holding member connected outside the reflection layers 3 and 4. 5 and 6.

The piezoelectric element 2 is made of a lead titanate ceramic and has an acoustic impedance Z ₁ of 3.4 × 10
^{It is 7} kg / (m ² · s). The piezoelectric element 2 is polarized in the direction of arrow P, that is, in the length direction.

The piezoelectric element 2 has a strip shape, and the upper surface, the lower surface, and a pair of side surfaces have a rectangular shape. In other words, the piezoelectric element 2 has a square rod shape. Excitation electrodes 7 and 8 are formed on a pair of opposed end faces 2a and 2b of the piezoelectric element 2. Excitation electrodes 7, 8
Is applied to the piezoelectric element 2 so that the end face 2
It vibrates in a length mode with a and 2b as length directions. That is, the piezoelectric element 2 is a piezoelectric resonance element using the length mode. In the piezoelectric resonator 1, terminal electrodes 9 and 10 are formed on the upper surface of the piezoelectric resonator 1 so as to be electrically connected to the excitation electrodes 7 and 8. The terminal electrodes 9 and 10 are provided not only on the upper surface of the piezoelectric resonator 1 but also on the holding members 5 which are end surfaces.
6 are formed so as to reach the outer end faces 5a, 6a.
Therefore, it can be easily surface-mounted on a printed circuit board or the like using the terminal electrodes 9 and 10. Reflective layers 3, 4
In this embodiment, the acoustic impedance is 1.87 × 1
Is composed of 0 ⁶ kg / epoxy resin is a (m ² · s). The holding members 5 and 6 are made of ceramics having an acoustic impedance of 3.4 × 10 ⁷ kg / (m ² · s).

In the piezoelectric resonance element utilizing the length mode, the propagation direction of the vibration is the length direction and the direction parallel to the polarization direction P, so that the end faces 2a and 2b are usually not affected by the vibration. I can't support it.

In this embodiment, the piezoelectric element 2 using the length mode has the reflection layers 3 and 4 and the holding members 5 and 6.
It is possible to support the piezoelectric resonator 1 without affecting the vibration characteristics. This will be described with reference to FIGS. In the following, the length refers to a dimension along the length direction of the piezoelectric resonator 1.

The length L ₁ of the piezoelectric element 2 is 0.98 mm, the resonator frequency F _{1 is} 2 MHz, and the length L ₂ of the reflection layers 3 and 4 is L ₂ =
The displacement state of the piezoelectric resonator 1 was analyzed by the finite element method with 0.25 mm and the length of the holding members 5 and 6 = 0.4 mm. The results are shown in FIG.

As is clear from FIG. 2, the holding members 5, 6
In, there is almost no displacement. Therefore, it is understood that the piezoelectric resonator 1 can be supported by using the holding members 5 and 6 without affecting the resonance characteristics of the piezoelectric element 2. This is because the acoustic impedance Z ₂ of the reflection layers 3 and 4 is lower than the acoustic impedance Z ₁ of the piezoelectric element 2 and lower than the acoustic impedance Z ₃ of the holding members 5 and 6. It is considered that the vibration transmitted from the piezoelectric element 2 is reflected at the interfaces A and B between the holding members 5 and 6, and the vibration hardly propagates to the holding members 5 and 6.

In view of the results of the piezoelectric resonator 1, the present inventors have variously changed the materials constituting the piezoelectric element 2, the reflective layers 3, 4 and the holding members 5, 6 in the piezoelectric resonator 1, and changed the dimensions thereof. As a result, the acoustic impedance Z ₂ of the first and second reflective layers 3 and 4 was determined as described above.
Acoustic impedance Z ₁ and the holding member 5 of the piezoelectric element 2,
If 6 smaller than the acoustic impedance Z ₃ of, found that it is possible to substantially suppress the propagation of vibration from the piezoelectric element 2 to the embodiment similarly to the holding member 5, 6. this,
A description will be given based on a specific experimental example with reference to FIGS. 4 and 5.

FIG. 4 shows impedance-frequency characteristics and phase-frequency characteristics when the piezoelectric resonator 1 is configured according to the following specifications. The solid line indicates the phase-frequency characteristics, and the broken line indicates the impedance-frequency characteristics. In addition, NE + On on the vertical and horizontal axes in FIGS. 4 and 5 indicates N × 10 ⁿ , for example, 1E + O 2 is 1 × 10 ² .

Specifications of the piezoelectric resonator 1 Piezoelectric element 2... Acoustic impedance Z ₁ = 3.4 × 10
It is composed of ⁷ kg / (m ² · s) lead titanate ceramics. Length dimension L ₁ = 412 mm, resonator circumference 5.4
MHZ reflective layers 3, 4... Acoustic impedance Z ₂ = 1.87 ×
Constructed of 10 ⁶ kg / (m ² · s) epoxy resin. Length dimension L ₂ = 0.07 mm Holding members 5, 6... Acoustic impedance Z ₃ = 3.4 ×
Constructed of 10 ⁷ kg / (m ² · s) lead titanate ceramics. Length dimension L ₃ = 300 mm The width dimension of the piezoelectric resonator 1 is 250 mm,
The thickness was 200 mm.

The piezoelectric resonator 1 was fixed to a substrate 11 by using a conductive adhesive 12 as shown in FIG. Note that, by fixing with the conductive adhesive 12, bonding with the conductive adhesive 12 is performed so as to secure a space between the lower surface of the piezoelectric element 2 and the upper surface of the substrate 11 so as not to hinder vibration.

The conductive adhesive 12 joins the terminal electrodes 9 and 10 to the electrodes 13 and 14 on the substrate 11, and the piezoelectric adhesive 2 and the reflective layers 3 and 4 are electrically conductive adhesive 12.
Is not attached.

FIG. 5 shows the frequency characteristics of the piezoelectric resonator 1 after being mounted on the substrate 11. Also in FIG. 5, the broken line shows the impedance-frequency characteristic, and the solid line shows the phase-frequency characteristic.

As is apparent from a comparison between FIG. 4 and FIG.
It can be seen that the frequency characteristics of the piezoelectric resonator 1 itself and the frequency characteristics of the piezoelectric resonator 1 fixed to the substrate 11 hardly change. That is, even if the piezoelectric resonator 1 is mechanically fixed to the holding members 5 and 6, the piezoelectric element 2
It can be seen that the resonance characteristics of are not impaired.

As is apparent from FIGS. 1 to 5, in the piezoelectric resonator 1 as a composite material vibration device constituted according to the present invention, reflection layers 3 and 4 are provided on both sides of a piezoelectric element 2 as a vibration member. It can be seen that by connecting the holding members 5 and 6 to the outside of the reflection layers 3 and 4, the piezoelectric resonator 1 can be supported without hindering the vibration of the piezoelectric element 2. This is shown more comprehensively in FIG. 6, and the composite material vibration device according to the present invention includes a vibration member 2 on both sides of a vibration member 21 as a vibration source.
The reflection layers 22 and 23 are connected so that the vibration from the first member 1 is propagated, and the holding member 2 is provided outside the reflection layers 22 and 23.
This corresponds to a structure in which 4, 25 are connected. In this case, as described above, the acoustic impedance Z ₂ of the reflection layers 22 and 23 is
Acoustic impedance Z ₁ of vibration member 21 and holding member 2
By making the acoustic impedance Z ₃ smaller than the acoustic impedance Z ₃ of the vibration member 21, the composite material vibration device 20 is mechanically supported by the holding members 24 and 25 without affecting the vibration characteristics of the vibration member 21, as in the above embodiment. I can do it.

That is, in the above embodiment, the piezoelectric element 2 was used as the vibration member. However, in the present invention, the impedance values Z _{1 to} Z ₃ of the vibration member As long as the above relationship can be satisfied, the vibration propagated at the interface between the reflective layers 22 and 23 and the holding members 24 and 25 can be reflected in the same manner as in the above-described embodiment. It is not something to be done. That is, as the vibration member 21, other than the piezoelectric element 2, an electrostrictive element or other members that generate various vibrations can be widely used.

The material forming the reflection layers 22 and 23 and the material forming the holding members 24 and 25 are not particularly limited, and any material may be used as long as the material satisfies the above relationship of the acoustic impedance value. it can.

The inventors of the present invention varied the materials forming the reflection layer in the piezoelectric resonator 1 and measured the respective changes in the resonance frequency and the bandwidth of the piezoelectric resonator 1. The results are shown in FIGS. Here, various different causes the epoxy resin constituting the ceramic and the reflection layer 3 and 4 constituting the piezoelectric element 2, the values were normalized acoustic impedance Z ₂ That is, the ratio Z ₂ / Z ₁ was variously different, resonance The frequency change rate (%) and the relative band change rate (%) were measured.

As is clear from FIGS. 7 and 8, the acoustic impedance ratio Z ₂ / Z ₁ is 0.2 or less, preferably 0.1
In the following, it can be seen that the rate of change of the resonance frequency is very small, at 0.2% or less, and is as low as 0.01% at 0.1 or less. Similarly, regarding the rate of change of the relative band, the acoustic impedance ratio Z ₂ / Z ₁ is 0.2 or less and -15% or less,
It turns out that it becomes -8% or less at 0.1 or less.

Therefore, the acoustic impedance ratio Z ₂ / Z ₁ is preferably set to 0.2 or less, more preferably 0.1 or less. In addition, the present inventors differed the materials constituting the reflection layers 3, 4 and the holding members 5, 6, varied the acoustic impedance ratio Z ₂ / Z ₃ , and similarly changed the frequency change rate of the piezoelectric resonator 1. (%) And the specific band change rate (%) were measured. The results are shown in FIGS.

As is clear from FIGS. 9 and 10, by setting the acoustic impedance ratio Z ₂ / Z ₃ to 0.2 or less, the frequency change rate is 0.2% or less and the relative bandwidth is -7%.
Hereinafter, it can be seen that by further setting the value to 0.1 or less, the relative bandwidth can be set to 0.05% or less and the specific bandwidth can be set to -6% or less. Therefore, the acoustic impedance ratio Z ₂ / Z ₃ is preferably
0.2 or less, more preferably 0.1 or less.

Also, the resonance frequency ratio and the ratio band change ratio of the piezoelectric resonator 1 were measured while changing the acoustic impedance ratio Z ₂ / Z ₁ . The results are shown in FIG. 11 and FIG. FIG.
In FIGS. 1 and 12, the acoustic impedance Z ₂ is reduced to the acoustic impedance Z ₁ by mixing epoxy resin, ceramics, or a powder having another acoustic impedance value as a material constituting the reflective layers 3 and 4. It is changed in an arbitrary range from 1/128.

The horizontal axis in FIGS. 11 and 12 is
The length in the length direction of the reflection layers 3 and 4 (the length along the length direction of the piezoelectric resonator 1) is obtained. The lengthwise dimension of the reflective layers 3 and 4 is, in other words, the dimension in the direction connecting the reflective layer surface connected to the piezoelectric element 2 as a vibration member and the reflective layer surfaces connected to the vibration members 5 and 6. That is, the dimension in the direction in which the vibration propagates through the reflecting surface.

As is apparent from FIGS. 11 and 12, the acoustic impedance ratio Z ₂ / Z ₁ is further reduced to 1/32.
Below, more preferably 1/64 or less, the reflective layer 3,
It can be seen that even if the length dimension of F.4 slightly changes from λ / 4, the rate of change of frequency and the rate of change of fractional band do not change much. Therefore, it is understood that, by setting Z ₂ / Z ₁ to preferably 1/32 or less, more preferably 1/64 or less, there are few restrictions on the lengthwise dimensions of the reflective layers 3 and 4.

However, as is apparent from FIGS. 11 and 12, regardless of the value of Z ₂ / Z ₁ ,
When the length dimension of the piezoelectric resonator 1 is at or near λ / 4, the rate of change of the frequency and the rate of change of the relative bandwidth of the piezoelectric resonator 1 are very small.

Further, the relationship between the thickness of the reflection layers 3 and 4 and the rate of change of frequency and the ratio of change in specific band was examined over a wider thickness of the reflection layers 3 and 4. The results are shown in FIGS. 13 and 14, respectively. Therefore, as is apparent from FIGS. 11 to 14, preferably, the length dimension of the reflection layers 3 and 4 is n · λ / 4 ±.
(Λ / 8) (n is an odd number), more preferably λ / 4 and its vicinity.

FIGS. 15A and 15B are a perspective view and a partially cutaway vertical sectional view showing a piezoelectric resonator as a composite material vibration device according to a second embodiment of the present invention. The piezoelectric resonator 31 is
It has a strip-shaped or square rod-shaped piezoelectric element 32.
The piezoelectric element 32 is a piezoelectric element using the sixth harmonic of the length mode. The piezoelectric resonator 31 of the present embodiment uses a piezoelectric element 32 instead of the piezoelectric
It has the same configuration as the piezoelectric resonator 1 of the first embodiment except that the electrode structure for exciting the piezoelectric resonator 2 is different.

In this embodiment, the piezoelectric element 32 is made of a lead zirconate titanate-based piezoelectric ceramic having an acoustic impedance value of 2.6 × 10 ⁷ kg / (m ² · s).

In order to excite the sixth harmonic of the length mode, the piezoelectric element 32 extends in the transverse section of the piezoelectric element 32.
Excitation electrodes 32a to 32f are formed. In other words, the excitation electrodes 32a to 32f are formed so as to be parallel to each other and to be positioned in the cross-sectional direction of the piezoelectric resonator 32 so that five piezoelectric layers exist between the excitation electrodes 32a to 23f. The five piezoelectric layers are uniformly polarized in the length direction.

A terminal electrode 37 is formed on the upper surface of the piezoelectric resonator 31 so as to be electrically connected to the excitation electrodes 32a, 32c and 32e. A terminal electrode 38 is formed on the lower surface of the piezoelectric resonator 31, and the excitation electrodes 32b, 32
d, 32f.

In order to electrically insulate the excitation electrodes 32b, 32d, 32f and the terminal electrode 37, the excitation electrodes 3
2b, 32d, and 32f have insulating materials 39a-
39c is provided. Similarly, the excitation electrodes 32a, 3
Insulating materials 39d to 39f are arranged at lower ends of the excitation electrodes 32a, 32c, and 32e in order to achieve electrical insulation between the terminal electrodes 38 and 2c and 32e.

The reflection layers 33 and 34 are located at both ends in the longitudinal direction of the piezoelectric element 32 and have an acoustic impedance ratio Z _2.
It is made of an epoxy resin satisfying / Z ₁ = 1/16.

Outside the reflection layers 33 and 34, holding members 35 and 36 made of lead zirconate titanate-based ceramics having an acoustic impedance ratio Z ₂ / Z ₃ = 1/16 are connected.

The terminal electrodes 37 and 38 are formed so as to reach the opposing end faces of the piezoelectric resonator 31, that is, the outer end faces 35a and 36a of the holding members 35 and 36.
Also in this embodiment, the reflection layers 33 and 34 and the holding member 3
The cross-sectional shapes of the piezoelectric elements 5 and 36 are the same as those of the piezoelectric element 32. Therefore, the piezoelectric resonator 31 has a square rod shape.

As in the second embodiment, the piezoelectric element 32 as a vibration member may use a harmonic in a length mode. FIG. 17 shows impedance-frequency characteristics and phase-frequency characteristics of the piezoelectric resonator 31. FIG.
As shown in FIG. 6, the impedance-frequency characteristics and the phase-frequency characteristics after the piezoelectric resonator 31 is bonded and fixed on the mounting substrate 41 using the conductive adhesives 42 and 43 are shown in FIG.
FIG. 17 and 18, a solid line indicates a phase-frequency characteristic, and a broken line indicates an impedance-frequency characteristic.

As is clear from the comparison between FIG. 17 and FIG. 18, also in the second embodiment, the characteristics before mounting on the mounting substrate 41 (that is, the piezoelectric resonator 31 alone) and the characteristics before mounting on the mounting substrate 41 are also shown. It can be seen that the characteristics after hardly changing.

Therefore, also in the second embodiment, even if the piezoelectric resonator 31 is mechanically held by the holding members 35 and 36, the resonance characteristics of the piezoelectric element 32 are hardly affected.

As shown in an exploded perspective view in FIG.
The plurality of piezoelectric resonators 31 may be joined via insulating adhesives 51 and 52 and mounted on the mounting substrate 53. In the structure shown in FIG. 19, two piezoelectric resonators 31, 31 are joined and electrically connected to form a filter circuit. Electrical connection between the two piezoelectric resonators 31 is made by conductive patterns 54 a to 54 d formed on the mounting substrate 53. A metal cap 55 is fixed on the mounting board 53. The metal cap 55 is fixed to the mounting board 53 using an insulating adhesive so as to surround and seal the piezoelectric resonators 31. The composite material vibrating device according to the present invention as in the filter component shown in FIG.
The present invention can be applied to not only a piezoelectric resonator but also a filter.

FIG. 20 is a perspective view showing a piezoelectric resonator according to a third embodiment of the present invention. The piezoelectric resonator 61 has a piezoelectric element 62 using a thickness shear mode. In the present embodiment, the piezoelectric element 62 has a rectangular plate shape made of piezoelectric ceramics, and an excitation electrode 63 is formed on an upper surface and an excitation electrode 64 is formed on a lower surface. The piezoelectric element 62 is polarized in its length direction. By applying an AC voltage from the excitation electrodes 63 and 64, the piezoelectric element 62 is excited in the thickness-shear mode.

Unlike the conventional energy trap type piezoelectric resonator 201 utilizing the thickness-shear mode (see FIG. 33), the piezoelectric element 62 has excitation electrodes 63 and 64 formed on the entire upper and lower surfaces. I have. Therefore, the piezoelectric element 62 is not an energy trap type piezoelectric resonator.

However, the reflection layers 65 and 66 and the holding members 67 and 68 are connected to both sides of the piezoelectric element 62 in the longitudinal direction, as in the first embodiment. The reflection layers 65 and 6
6, the piezoelectric element 62 and the holding members 67, 68
Is about λ / 4, where λ is the wavelength of the transmitted vibration. And the resonance electrode 6
3, 64 are connected to terminal electrodes 69, 70. The terminal electrodes 70 and 69 are formed so as to reach the end faces of the piezoelectric resonator 62, that is, the outer end faces 67 a and 68 a of the holding members 67 and 68.

In the piezoelectric resonator 61 of this embodiment, the piezoelectric element 62 is not of the energy trap type,
5, 66 and holding members 67, 68 are configured in the same manner as in the first embodiment. Further, an acoustic impedance Z ₁ of the piezoelectric element 62, the acoustic impedance Z ₂ of the reflective layer 65 and 66, acoustic impedance Z ₃ of the holding member 67 and 68 are selected as in the first embodiment Therefore, the vibration propagated in the length direction from the piezoelectric element 62 is
The light is reflected at the interface between 66 and the holding members 67 and 68. Therefore, even if the piezoelectric element 62 is mechanically supported by the holding members 67 and 68 as in the first embodiment, the resonance characteristics of the piezoelectric element 62 are hardly affected. As described above, even when the thickness-shear mode is used, by using the present invention, the vibration damping portion can be eliminated, and the size of the piezoelectric resonator using the thickness-shear mode can be reduced. .

That is, since the thickness of the reflection layers 65 and 66 (the dimension along the length direction of the resonance 61) may be about λ / 4,
There is no need for a large vibration damping unit as in the conventional energy trap type piezoelectric resonator 201. The holding member 6
The lengths of the piezoelectric resonators 61 and 68 along the length direction of the piezoelectric resonator 61 may be very small, and only the reflection surface is required. Therefore, the piezoelectric resonator 61 has a longer length than the piezoelectric resonator 201. The size can be reduced.

The frequency characteristics of the piezoelectric resonator 61 of the present embodiment,
In addition, as shown in FIG. 21, the frequency characteristics in a state where the piezoelectric resonator 61 is fixed on the mounting substrate 71 using the conductive adhesives 72 and 73 hardly changed. The broken line in FIG. 22 indicates the impedance-frequency characteristic, and the solid line indicates the phase-frequency characteristic. In FIG. 22, the characteristic after being mounted on the mounting board 71 is shown. Is omitted. The piezoelectric resonator as the composite material vibration device according to the present invention is not limited to the one using the vibration mode used in the first to third embodiments, and the vibration mode of the piezoelectric element as the vibration member is not particularly limited. .

FIG. 23 is a schematic sectional view showing a modified example of a piezoelectric resonator as a composite material vibration device according to the present invention. In the piezoelectric resonator 81 shown in FIG. 23, a rectangular plate-like piezoelectric element 82 utilizing thickness longitudinal vibration is used. Excitation electrodes 83 and 84 are formed on the upper and lower surfaces of the piezoelectric element 82 so as to face each other with the piezoelectric element 82 interposed therebetween.
On the upper and lower surfaces of the piezoelectric element 82, ceramic plates 87, 88 as a holding member are laminated via reflection layers 85, 86. Terminal electrodes 89 and 90 electrically connected to the excitation electrodes 83 and 84 are formed on the outer surface of the piezoelectric resonator 81, respectively.

A piezoelectric element utilizing the thickness longitudinal vibration mode, such as the piezoelectric element 82, may be used as the vibration member in the present invention. Further, the piezoelectric element 8 like the piezoelectric resonator 81 is used.
The reflective layers 83 and 84 and the holding members 87 and 88 may be stacked on the upper and lower sides of the two.

Further, the present invention can be applied to a piezoelectric resonator utilizing a laminated thickness longitudinal vibration mode, such as a piezoelectric resonator 91 shown in FIG. Here, the piezoelectric element 92 includes, in addition to the excitation electrodes 93 and 94, the piezoelectric element 92.
It has internal electrodes 95 and 96 formed therein. Therefore,
A piezoelectric element 92 using harmonics of thickness longitudinal vibration is configured. Reflection layers 83 and 84 and holding members 87 and 88 are stacked above and below the piezoelectric element 92, similarly to the piezoelectric resonator 81.

In the composite material vibration device according to the present invention, when the vibration direction of the vibration member is A, the vibration propagation direction of the vibration member is B, and the vibration propagation direction of the reflection layer is C, a combination of directions A to C is provided. Can be appropriately modified.

That is, like the piezoelectric resonators 101 to 103 shown in FIGS. 25A to 25C, the directions A and B are parallel to each other, and the directions B and C are orthogonal to each other. May be. 25 (a) to 25 (c) show piezoelectric resonators using length vibration, and each of the piezoelectric elements 101a, 101b, 101c is polarized in the direction of the arrow shown in the figure. 104a is a reflection layer, 1
04b indicates a holding member.

That is, in the present invention, the vibration member
The reflective layer perpendicular to the vibration propagation direction
Good. Solve the displacement distribution of such a structure by the finite element method.
The results of the analysis are shown in FIG. In FIG. 26, the vibration member
And the acoustic impedance value Z ₁Is 3.0 × 10⁷kg /
(M^Two・ S) The length L₁But
0.98mm, length mode with resonator frequency 2MHz
A piezoelectric element 106 using a metal is formed. This pressure
On the side surface of the piezoelectric element 106,
The reflection layers 107 and 10 extend in a direction orthogonal to the dynamic propagation direction.
8 are arranged. The reflection layers 107 and 108
Impedance value Z_TwoIs 1.87 × 10⁶kg / (m^Two・
s), thickness (piezoelectric element 106 and reflective layers 107 and 108)
From the interface of to the surface on the opposite side of the reflective layers 107 and 108
Direction dimension) is set to 0.15 mm. Holding member 10
9,110 is the acoustic impedance Z_Three= 3.0 × 10
⁷kg / (m^Two・ S) Lead zirconate titanate ceramic
And is connected to the reflection layers 107 and 108.
I have.

As is clear from FIG. 26, the piezoelectric resonator 1
Also in 05, it can be seen that the vibration hardly leaks to the holding members 109 and 110. Therefore, in the composite material vibration device according to the present invention, the reflection layer may be connected in a direction orthogonal to the vibration propagation direction in the vibration member. Such an example is shown in FIGS.
This is embodied in the piezoelectric resonators 101 to 103 shown in FIG.

Also, like the piezoelectric resonators 111 and 112 schematically shown in FIGS. 27A and 27B, the vibration propagation directions of the piezoelectric elements 111a and 112a using the thickness longitudinal vibration mode (indicated by arrows). The reflection layers 113 and 114 may be arranged in a direction perpendicular to the polarization direction (parallel to the polarization direction). Note that the piezoelectric element 112a shown in FIG. 27B is a stacked-type piezoelectric resonance element having internal electrodes and utilizing thickness longitudinal vibration.

In FIGS. 27A and 27B, the reflection layers 113 and 114 are arranged on both sides of the piezoelectric elements 111a and 112a using the thickness longitudinal vibration in the direction orthogonal to the vibration propagation direction of the piezoelectric elements 111a and 112a. Have been. Also,
The holding members 115 and 114 are provided on the surface opposite to the surface where the reflection layers 113 and 114 are coupled to the piezoelectric elements 111a and 112a.
116 are connected.

Further, in the composite material vibration device according to the present invention, as in the piezoelectric resonator 117 shown in FIG. 28, the vibration displacement direction of the vibration member is orthogonal to the vibration propagation direction of the vibration member, and the vibration of the vibration member is The direction of propagation and the direction of vibration propagation in the reflective layer may be parallel. The piezoelectric resonator 117 includes a piezoelectric element 117a.
The piezoelectric element 117a has a structure in which excitation electrodes 118 and 119 are formed on both main surfaces of piezoelectric ceramics, and is polarized in the direction of the paper surface-back direction in FIG. Therefore, the piezoelectric element 117a is a piezoelectric element utilizing the thickness torsional vibration mode. The reflection layer 11 is provided outside the piezoelectric element 117a.
3, 114 and holding members 115, 116 are connected.

FIGS. 25 to 28 and FIGS.
As apparent from (c), in the present invention, the vibration displacement direction of the vibration member, the vibration propagation direction in the vibration member,
It can be configured in various relations with the vibration propagation direction in the reflective layer, and in any case, as long as the above-described acoustic impedances Z _{1 to} Z ₃ satisfy the above-described specific relation, the first
As in the embodiment, the piezoelectric resonator can be mechanically held by the holding member without affecting the resonance characteristics of the piezoelectric element.

The present invention can be applied to other resonators and filters utilizing the piezoelectric effect, for example, surface acoustic wave devices. FIG. 29 is a plan view showing a surface acoustic wave resonator as a fourth embodiment of the composite material vibration device according to the present invention. In the surface acoustic wave resonator 121, the rectangular plate-shaped piezoelectric substrate 12
2, first and second interdigital transducers (IDTs) 123 and 124 are arranged separated from each other in the surface acoustic wave propagation direction. Then, the first and second reflective layers 125, 1 are provided outside the piezoelectric plate 122 in the surface wave propagation direction.
26 are connected, and holding members 127 and 128 made of a ceramic plate are connected to the outside of the reflection layers 125 and 126. Here, the acoustic impedance Z ₁ of the piezoelectric plate 122, the acoustic impedance Z ₃ of the acoustic impedance Z ₂ and the holding member 127 and 128 of the reflective layer 125 and 126 is selected as in the first embodiment, The surface waves are reflected at the interfaces between the reflection layers 125 and 126 and the holding members 127 and 128, and can operate as surface acoustic wave resonators. Therefore, since the reflector can be omitted, the size of the surface acoustic wave resonator can be reduced.

The piezoelectric resonator 1 shown in FIGS.
31 to 133 are vibration displacement directions A of the vibration member, respectively.
FIG. 4 is a schematic cross-sectional view showing a piezoelectric resonator in which a vibration propagation direction B in a vibration member and a vibration propagation direction C in a reflection layer are orthogonal to each other.

In the piezoelectric resonator 131, a piezoelectric element 134 using a thickness-shear mode is used. Here, the piezoelectric element 134 is polarized in the direction of the arrow shown in the figure, has excitation electrodes 135 and 136, and the vibration displacement direction A has a component parallel to the excitation electrode but has a component perpendicular thereto. The vibration propagation direction B of the piezoelectric element 134 is parallel to the excitation electrodes 135 and 136. On the other hand, the reflection layers 137 and 138 are connected to the lower surface of the piezoelectric element 134, and the vibration propagation direction in the reflection layers 137 and 138 is orthogonal to the vibration propagation direction in the piezoelectric element 134. The holding members 139a and 139b are connected to surfaces of the reflection layers 137 and 138 opposite to the surfaces connected to the piezoelectric element 134.

In FIG. 30B, a holding member 140 is used, and the holding member 140 corresponds to a structure in which the holding members 139a and 139b in FIG.

As described above, the holding member provided outside the reflection layer may be connected to both the first and second reflection layers. In the piezoelectric resonator 133 shown in FIG. 30C, a piezoelectric element 141 utilizing thickness torsional vibration is used.
Other points are the same as those of the piezoelectric resonator 1 shown in FIG.

As described above, in the composite material vibration device according to the present invention, a piezoelectric element utilizing various vibration modes can be used as the vibration member, but an electrostrictive effect element is used instead of the piezoelectric element. May be used. Furthermore, not only electromechanical coupling conversion elements such as piezoelectric elements and electrostrictive elements, but also vibration sources that generate various vibrations can be used as the vibration member of the composite material vibration device according to the present invention.

Further, in the present invention, the connection relationship between the vibration member, the reflection layer and the holding member is not limited to the above-described embodiments and modifications. For example, FIGS. 31 (a), (b),
As shown in (c) and FIG. 32, a composite material vibration device using a plurality of vibration members can also be configured.

In the composite vibration device shown in FIG. 31A, the first and second vibration members 151 and 152 are
3, the first and second vibrating members 15
The reflection layers 154 and 155 and the holding members 156 and 157 are connected to the outside of each of the reference numerals 1 and 152. Here, the reflection layers 155 and 156 constitute the first and second reflection layers of the present invention, and the holding members 156 and 157 constitute the first and second holding members of the present invention. The structure in which the first and second vibration members 151 and 152 are connected by the reflection layer 153 can be understood as one vibration member of the composite material vibration device according to the present invention. Further, since the first and second vibration members 151 and 152 are connected via the reflection layer 153, the vibration propagated from the first vibration member to the reflection layer 153 side is transmitted to the reflection layer 153 and the second layer. Vibration member 152
Vibration that is reflected at the interface between the vibration member 152 and the reflection layer 153 is reflected at the interface between the reflection layer 153 and the first vibration member 151.

In the composite vibration device shown in FIG. 31B, the first and second reflection layers 16 are provided on both sides of the vibration member 161.
2, 163 are connected, and the first and second reflection layers 16 are connected.
The holding members 164 and 165 are connected to the outside of the holding members 2 and 163. That is, the structure up to here is the same as that of the first embodiment. The difference is that the third reflection layer 166, the second vibration member 167,
The fourth reflective layer 168 and the third holding member 169 are connected in this order. Here, the vibration generated by the second vibration member 169 is reflected by the interface between the reflection layers 166 and 168 and the holding members 165 and 169. In other words, the structure corresponds to a structure in which two composite material vibrators are connected to each other by preparing two composite material vibrators according to the first embodiment and also serving as one of the holding members.

In the composite material vibrating device 171 shown in FIG. 32, composite material vibrating devices 172 and 173 configured in the same manner as in the first embodiment are connected via a reflective layer 174.

As shown in FIG. 31C, the reflection layers 182 and 183 and the holding member 1 are provided on both sides of the vibration member 181.
84, 185 and each holding member 18
The reflection layers 186, 187 and the holding members 188, 189 may be connected to the outside of the fourth, 185.

[0089]

According to the composite material vibration device of the present invention, the vibration
The first and second reflection layers are connected to both sides of the motion source.
The side of the first and second reflection layers to which the vibration member is connected.
The first and second holding members are connected to the opposite side to
Acoustic impedance value Z of reflective layer _TwoIs a vibration member and holding
Acoustic impedance value Z of the member₁, Z_ThreeLower than
Vibration at the interface between the reflective layer and the holding member
The vibration propagated from the member to the reflection layer is reflected. Follow
Without affecting the vibration characteristics of the vibration member.
1, can be mechanically supported by the second holding member
You.

In the present invention, the reflection layer and the holding member are connected to the vibration member as described above, and the vibration transmitted to the reflection layer is reflected at the interface between the reflection layer and the holding member. The vibration mode and the specific structure of are not particularly limited. Therefore, for example, when a piezoelectric vibration element is used as a vibration member, various vibration modes such as a length vibration mode, a bending vibration mode, and a spreading mode can be used, and a conventional energy trap type piezoelectric vibration element can be configured. By utilizing the vibration mode that was not present, a composite material vibration device that can be supported without requiring a complicated support structure such as a spring terminal can be configured.

Further, even in a conventional piezoelectric resonator or the like utilizing the energy trapping type thickness-shear mode, a vibration damping portion having a relatively large area had to be formed. Does not require such a vibration damping unit. Therefore, when the vibration mode is used, a smaller piezoelectric resonator or piezoelectric filter can be provided by using the present invention as compared with a conventional energy trap type piezoelectric vibration element.

The acoustic impedance ratio Z ₂ / Z ₁ is 0.2
In the case of the following, the composite material vibration device can be supported on the holding member without substantially affecting the vibration characteristics of the vibration member, and similarly, the acoustic impedance ratio Z ₂ / Z ₃ is 0.2 or less. In this case, even if the vibration member is mechanically supported by the holding member, the vibration characteristics of the vibration member can be further reduced.

The first and / or second holding members 1 and 2
When the third reflection layer, the second vibrating member, the fourth reflection layer, and the third holding member are connected in this order on the side opposite to the side where the second reflection layer is connected. According to the present invention, a filter or the like using two vibration members can be easily configured. Further, the first holding member, the first reflection layer, the first vibration member, the second reflection layer, the second vibration member,
According to the present invention, a composite vibration device in which the third reflection layer and the second holding member are connected in this order is also provided.
Since it is possible to mechanically support the first and second holding members without affecting the vibration characteristics of the first and second vibration members, a small piezoelectric filter or composite using various vibration modes can be used. A piezoelectric resonance component or the like can be provided.

In the present invention, the distance from the interface between the reflection layer and the vibration member to the interface between the reflection layer and the holding member is represented by n · λ / 4 ± λ /, where λ is the wavelength of the transmitted vibration.
In the case of the range of 8, the effect of the vibration characteristics of the vibration member when mechanical support is performed by the holding member can be further reduced.

[Brief description of the drawings]

FIGS. 1A and 1B are a perspective view and a longitudinal sectional view showing a piezoelectric resonator as a composite material vibration device according to a first embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing a displacement distribution of the piezoelectric resonator shown in FIG. 1 analyzed by a finite element method.

FIG. 3 is a perspective view showing a state in which the piezoelectric resonator according to the first embodiment is mounted on a mounting substrate.

FIG. 4 is a view showing resonance characteristics of the piezoelectric resonator according to the first embodiment before being mounted on a mounting substrate.

FIG. 5 is a diagram showing resonance characteristics after the piezoelectric resonator according to the first embodiment is mounted on a mounting substrate.

FIG. 6 is a schematic configuration diagram of a composite material vibration device according to the present invention.

FIG. 7 is a diagram showing the relationship between the acoustic impedance ratio Z ₂ / Z ₁ and the rate of change of the resonance frequency in the piezoelectric resonator of the first embodiment.

FIG. 8 is a view showing the relationship between the acoustic impedance ratio Z ₂ / Z ₁ and the rate of change of the specific band in the piezoelectric resonator of the first embodiment.

FIG. 9 is a diagram showing a relationship between an acoustic impedance ratio Z ₂ / Z ₃ and a resonance frequency change rate in the piezoelectric resonator of the first embodiment.

FIG. 10 is a diagram showing the relationship between the acoustic impedance ratio Z ₂ / Z ₃ and the rate of change of the specific band in the piezoelectric resonator of the first embodiment.

FIG. 11 is a diagram showing the relationship between the dimension of the reflection layer along the length direction of the piezoelectric resonator and the rate of change in the resonator frequency when a reflection layer having various acoustic impedances is used.

FIG. 12 is a diagram showing the relationship between the dimension of the reflection layer along the length direction of the piezoelectric resonator and the rate of change of the fractional band when the reflection layer has various acoustic impedances.

FIG. 13 is a diagram showing a frequency change rate when the thickness of the reflection layer, that is, the dimension along the length direction of the piezoelectric resonator is changed.

FIG. 14 is a view showing a ratio band change rate when the thickness of the reflection layer, that is, the dimension along the length direction of the piezoelectric resonator is changed.

FIGS. 15A and 15B are a perspective view and a partially cutaway longitudinal sectional view of a piezoelectric resonator according to a second embodiment of the present invention.

FIG. 16 is a perspective view showing a state in which the piezoelectric resonator according to the second embodiment is mounted on a mounting board.

FIG. 17 is a diagram illustrating resonance characteristics before the piezoelectric resonator according to the second embodiment is mounted on a mounting substrate.

FIG. 18 is a diagram illustrating resonance characteristics of a state after the piezoelectric resonator according to the second embodiment is mounted on a mounting substrate.

FIG. 19 is an exploded perspective view for explaining an application example as a filter component using two piezoelectric resonators.

FIG. 20 is a perspective view showing a piezoelectric resonator using a thickness-shear mode as a third embodiment of the composite material vibration device according to the present invention.

FIG. 21 is a perspective view showing a state in which the piezoelectric resonator of the third embodiment is mounted on a mounting board.

FIG. 22 is a diagram illustrating resonance characteristics when the piezoelectric resonator according to the third embodiment is mounted on a mounting substrate.

FIG. 23 is a schematic cross-sectional view showing a piezoelectric resonator using thickness longitudinal vibration as a modified example of the composite material vibration device of the present invention.

FIG. 24 is a schematic cross-sectional view for explaining a piezoelectric resonator using a laminated thickness longitudinal vibration mode as another modified example of the composite material vibration device according to the invention.

FIGS. 25A to 25C are schematic cross-sectional views showing modifications of the piezoelectric resonator using the length mode configured according to the present invention.

FIG. 26 is a diagram showing a displacement distribution analyzed by a finite element method having a configuration in which a reflective layer is arranged in a direction orthogonal to a vibration propagation direction of a piezoelectric element using a length mode in the present invention.

FIGS. 27 (a) and 27 (b) show modified examples of a piezoelectric resonator configured according to the present invention, in which a reflection layer and a holding member are connected to both sides of a piezoelectric element utilizing thickness longitudinal vibration. FIG.

FIG. 28 is a schematic sectional view of a piezoelectric resonator having a piezoelectric element using a thickness torsion mode as a vibration member, which is a composite material vibration device configured according to the present invention.

FIG. 29 is a plan view showing a surface acoustic wave resonator as another modified example of the composite material vibration device according to the present invention.

FIGS. 30A to 30C are schematic cross-sectional views showing piezoelectric resonators using a thickness shear mode as a modified example of the composite material vibration device according to the present invention.

FIGS. 31 (a) to (c) are schematic block diagrams of a composite material vibrating device according to the present invention.
A modified example of the composite material vibration device having the vibration member of FIG.

FIG. 32 is a schematic block diagram showing another example of the composite material vibrating device according to the present invention having first and second vibrating members.

FIG. 33 is a schematic partial cutaway longitudinal sectional view illustrating a state in which a conventional energy trap type piezoelectric resonator is mounted on a substrate.

FIG. 34 is a longitudinal sectional view showing an example of a conventional bulk acoustic wave filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1: Piezoelectric resonator (composite material vibration device) 2: Piezoelectric element 3, 4 ... 1st, 2nd reflection layer 5, 6 ... 1st, 2nd holding member 7, 8 ... Excitation electrode 9, 10 ... Terminal Electrode 31: Piezoelectric resonator (composite material vibration device) 32: Piezoelectric element (composite material vibration device) 33, 34 ... First and second reflective layers 35, 36 ... First and second holding members 61 ... Piezoelectric resonance Element (composite material vibrating device) 62 piezoelectric element 65, 66 reflective layer 67, 68 holding member 81 piezoelectric resonator 82 piezoelectric element 85, 86 reflective layer 87, 88 holding member 91 piezoelectric resonator 92 ... piezoelectric elements 101 to 103 ... piezoelectric resonators 104 ... piezoelectric elements 105 and 106 ... reflection layers 107 and 108 ... holding members 111 and 112 ... piezoelectric resonators 111a and 112a ... piezoelectric elements 113 ... piezoelectric resonators 113a ... piezoelectric elements 115 and 116 ... Anti Emissive layers 117, 118 ... Holding member 121: Surface wave resonator 122 ... Piezoelectric plates 125, 126 ... Reflective layers 127, 128 ... Holding members 151, 152 ... Vibrating members 153 ... Reflective layers 154, 155 ... Reflective layers 156, 157 ... Holding member 161 First vibration member 162, 163 First and second reflection layers 164, 165 First and second holding members 166 Reflection layer 167 Vibration member 168 Reflection layer 169 Holding member 171 … Composite material vibration device 172,173… Composite material vibration device 174… Reflection layer

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Kaida 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (Reference) 5J108 AA07 BB04 CC04 CC13 DD01 DD02 DD06 DD07 DD08 EE03 EE07 EE18 FF01 GG03 JJ01

Claims (13)

[Claims] 1. A composite material vibration device in which a plurality of material portions having different acoustic impedances are combined, comprising: a vibration member made of a material having a _first acoustic impedance value Z ₁ and serving as a vibration generation source; first and second reflective layer, the second acoustic coupled to both sides of the first of a material having a second acoustic impedance Z ₂ is lower than the acoustic impedance Z _1, and the vibrating member large third than the impedance value Z ₂
Made of a material having an acoustic impedance value Z ₃ of the first, and a retaining member connected to the side opposite to the side where the vibrating member of the second reflective layer are connected, the holding and the reflective layer A composite material vibrating device characterized in that vibrations propagated from the vibrating member to the reflective layer at an interface with the member are reflected. 2. A ratio of the first acoustic impedance Z ₁ of the second acoustic impedance value Z ₂ Z ₂ / Z ₁
The composite material vibration device according to claim 1, wherein is less than or equal to 0.2. Wherein the second third of the ratio Z ₂ / Z ₃ for the acoustic impedance Z ₃ of the acoustic impedance Z ₂ is 0.2 or less, the composite material vibration device according to claim 1 or 2. 4. The composite material vibration device according to claim 1, wherein said vibration member is an electromechanical coupling conversion element. 5. The composite material vibration device according to claim 4, wherein said electromechanical coupling conversion element is a piezoelectric element or an electrostrictive element. 6. A third reflection layer, a second vibrating member, and a first and / or second holding member on a side opposite to a side where the first and second reflection layers are connected. The fourth reflection layer and the third holding member are connected in this order.
The composite material vibrating apparatus according to any one of claims 1 to 5. 7. A composite material vibration device in which a plurality of material portions having different acoustic impedances are combined, wherein the first and second materials are made of a material having a _first acoustic impedance value Z1 and serve as vibration sources. A second acoustic member, a reflective layer made of a material having a _second acoustic impedance value Z2 lower than the _first acoustic impedance value Z1, and a third acoustic impedance Z greater than the _second acoustic impedance Z2. _A first holding member, a first reflection layer, a first vibration member, and a second holding member.
The reflection layer, the second vibration member, the third reflection layer, and the second holding member are connected in this order, and each vibration generated by the first and second vibration members is the first or third vibration member. A reflective layer,
A composite material vibration device, which is reflected by an interface with a first or second holding member and by an interface of the second reflection layer with a second vibration member or a first vibration member. 8. The composite material vibration device according to claim 1, wherein said reflection layer is formed by laminating a plurality of material layers having different acoustic impedances. 9. When the wavelength of vibration when the vibration member vibrates alone is λ, the distance from the interface between the reflection layer and the vibration member to the interface between the reflection layer and the holding member is n ·.
The composite material vibration device according to any one of claims 1 to 8, wherein the composite material vibration device is in a range of λ / 4 ± λ / 8 (n is an odd number). 10. When the vibration displacement direction of the vibration member is A, the vibration propagation direction in the vibration member is B, and the vibration propagation direction in the reflection layer is C, the directions A to C are parallel to each other. 6. The composite material vibration device according to 5. 11. When the vibration displacement direction A of the vibration member, the vibration propagation direction B in the vibration member, and the vibration propagation direction in the reflection layer are C, the direction A and the direction B are parallel, and the direction B and the direction are parallel. 6. C is orthogonal to C.
The composite material vibration device according to claim 1. 12. When a vibration displacement direction A of the vibration member, a vibration propagation direction B in the vibration member, and a vibration propagation direction C in the reflection layer, the direction A is orthogonal to the direction B, and the direction B is 6. The composite vibration device according to claim 5, wherein the direction C is parallel. 13. A vibration displacement direction A of the vibration member, a vibration propagation direction B in the vibration member, and a vibration propagation direction C in the reflection layer, the direction A is orthogonal to the direction B, and the direction B is The direction C is orthogonal to the direction C,
The composite material vibration device according to claim 5.