JPH08125491A - Piezoelectric resonance component - Google Patents

Abstract

PURPOSE: To obtain a stable characteristic in which the characteristic is not changed even with application of an external shock by coating an elastic body to a position of a terminal board except a projection of one side so as to suppress termination resonance thereby suppressing production of spurious vibration without increasing the thickness of the terminal board, the number of components requiring large sizes and assembling man-hours or the like. CONSTITUTION: Electrodes to generate spread vibration are formed to both major sides of series resonators 43, 44 and parallel resonators 45, 46 being piezoelectric elements. Projections 47b-53b are formed in the middle of plates 47a to 53a of terminal boards 47 to 52 and a U-shaped terminal board 53 to hold the series resonators 43, 44 and the parallel resonators 45, 46. Then elastic bodies 54 to 57 are coated to the side except one side with the projections 47b to 54b formed thereon. Thus, the vibration delivered from the piezoelectric element to the terminal boards 47 to 53 is absorbed by the elastic bodies 54 to 57 to attenuate terminal resonance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonance component using a piezoelectric element in a spreading vibration mode, and more particularly to a piezoelectric resonance component used for a piezoelectric filter, a piezoelectric oscillator or the like.

[0002]

2. Description of the Related Art Conventionally, a piezoelectric resonance component used for a piezoelectric filter, a piezoelectric oscillator or the like using a piezoelectric element of a spreading vibration mode includes some piezoelectric elements as series resonators or parallel resonators, and between these elements. It is often used that a terminal plate that is inserted in the terminal and that also functions as an input / output electrode with an external circuit is combined and these are incorporated in a case. The terminal plate usually has a plate-like portion inserted between the piezoelectric elements having substantially the same size as the piezoelectric element, and has a projection portion in the center thereof for electrically conducting while holding the piezoelectric element, and At one end of the plate-shaped portion, there is a pull-out portion that is pulled out from the case to connect with an external circuit.

In the piezoelectric resonance component having such a structure, when vibration or impact is applied from the outside, the protrusion holding the piezoelectric element is displaced and the resonance characteristic is changed.
There is a problem that spurious vibrations may occur.

On the other hand, it has been conventionally proposed to interpose an elastic body between the piezoelectric element and the terminal plate or between the terminal plates in order to prevent the protrusion from being displaced due to an impact. One such example is shown in FIG.

FIG. 3 is a sectional view showing a part of the structure of the conventional piezoelectric resonance component 1. In the figure, 2 and 3 are piezoelectric elements (series resonators or parallel resonators) of a spreading vibration mode in which electrodes (not shown) are formed on both main surfaces,
4-9 has shown the terminal board, respectively. Terminal board 4/6
9 is a plate-like portion 4a, 6a, 9a having substantially the same area as the piezoelectric element.
Has protrusions 4b, 6b, and 9b in the center thereof. The terminal plates 5, 7 and 8 are also plate-shaped parts 5a and 7a.
.Protrusions 5b, 7b, 8b are provided at the central portion of 8a, and a lead-out portion 5c for connection with an external circuit is provided.
It has 7c and 8c. As shown in the drawing, these terminal plates 4 to 9 are assembled two by two so that the protrusions are on the outside, and between the protrusions of adjacent pairs of terminal plates, between 5b-6b and 7b in the figure. Piezoelectric element 2.3 between 8b
Holding Reference numerals 10 to 13 denote conductive rubbers, which are interposed between the piezoelectric elements 2 and 3 and the projections of the terminal plates 4 to 9.

According to such a piezoelectric resonance component 1, the piezoelectric element 2 from the terminal plates 5 to 8 via the conductive rubbers 10 to 13
3 is applied, and at the same time, the conductive rubbers 10 to 13 absorb vibrations from the piezoelectric elements 2.3 to the projections 5a to 8a and shocks from the outside.
Is transmitted to each of the protrusions 5a to 8a to cause spurious vibration due to terminal resonance, and the protrusions are not displaced due to an external impact to change the resonance characteristics.

Further, in Japanese Utility Model Application Laid-Open No. 48-20346, there is used a terminal plate as shown in the sectional view of FIG. 4, in which the back surface of the projection of the terminal board is filled and bonded with a synthetic resin to make the entire back surface flat. Previously disclosed piezoelectric resonant components are disclosed. In the figure, in the piezoelectric resonance component 14, the piezoelectric resonators 16 to 18 and the terminal plates 19 to 23, which are piezoelectric elements, are provided inside the insulating case 15, and the respective terminal plates 19 to
Circular arc-shaped projections 19b-23b formed in the center of 23 to 23 are arranged so as to abut the vibration nodes of the piezoelectric resonators 16-18. On the back surface of each of these protrusions 19b-23b, the protrusions 19b-21
b to the recess on the back surface, and projections 22b and 23b to the entire back surface including the recesses.
c to 23c are filled and adhered. And the insulation case 15
A lid 24 is joined to the inner space to seal the inner space.

Further, Japanese Utility Model Laid-Open No. 5-78033 proposes a piezoelectric resonance component having an elastic body coated on the back surface of the projection of the terminal plate, as shown in the sectional view of FIG. In the piezoelectric resonance component 25 of the same figure, 26 and 27 are series resonators that are piezoelectric elements, 28 and 29 are parallel resonators that are also piezoelectric elements, 30 to 35 are terminal plates, and 36 is a U-shaped terminal plate. Is. The terminal plates 30 to 35 and the U-shaped terminal plate 36 are respectively provided with the plate-shaped portion 30a.
.About.36a have protrusions 30b to 36b in the center thereof, thereby holding the series resonators 26 and 27 and the parallel resonators 28 and 29. Further, the terminal plates 30, 32, 34, 35 have lead portions 30c, 32c, 34c, 35c for connecting to an external circuit. In the piezoelectric resonance component 25, 30c is an input terminal,
34c is an output terminal and 32c and 35c are ground terminals. In addition, 37 and 38 are elastic bodies, and these are projections 36b and 31b.
And it is applied only to the back surface of 33b and 34b. Then, these are incorporated in the case 39 to form the piezoelectric resonance component 14. Incidentally, 40 is an insulator and 41 is a spring.

According to such a piezoelectric resonance component 25, even if the protrusion of the terminal plate is displaced from the node point, the series resonator
26 and the vibration from the parallel resonator 28 are caused by the elastic body 37.
Further, the vibrations from the series resonator 27 and the parallel resonator 29 are absorbed by the elastic body 38 and are not transmitted to the respective terminal plates, so that terminal resonance does not occur, and the series resonators 26 and 27 and the parallel resonators 28 and 29 are not generated. That is, spurious vibrations do not occur, and the characteristics do not change even when an impact is applied to the piezoelectric resonance component 25.

[0010]

However, even the configurations of the above proposals have the following problems.
That is, in the configuration of the piezoelectric resonance component 1 shown in FIG. 3, the conductive rubbers 10 to 13 are provided between the piezoelectric elements 2 and 3 and the terminal plates 5 to 8.
Therefore, the number of components is increased and the piezoelectric resonance component 1
There was a problem that the size of the becomes large.
In addition, the number of assembly steps of the components is increased accordingly, resulting in an increase in the manufacturing cost, which raises the product price of the piezoelectric resonance component or makes it easier to make an assembly error.

The piezoelectric resonance component 14 using the terminal plate proposed in Japanese Utility Model Laid-Open No. 48-20346 also provides an arc-shaped projection.
Filling the back surfaces of the terminal plates 19-23 including the back surfaces (recesses) of 19b-23b with synthetic resins 19c-23c is not suitable for mass production.
There is a problem that the pitch deviation between the terminal plates 19 to 23 easily occurs due to the variation in the amount of synthetic resin.

Further, the structure of the piezoelectric resonant component 25 proposed in Japanese Utility Model Laid-Open No. 5-78033 is similar to the piezoelectric resonant component 14 of Japanese Utility Model Laid-Open No. 48-20346, and terminal plates 30 to 35 and U-shaped terminals are provided. Elastic members 37 and 38 are provided only on the back surfaces of the projections 30b to 36b of the plate 36.
There is a problem in that the application of the product increases the product price because the number of manufacturing steps of the terminal board increases.

The present invention has been completed as a result of intensive research conducted by the present inventors in view of the above problems, and an object thereof is to increase the number of assembling steps without increasing the number of large-sized parts. It is an object of the present invention to provide a piezoelectric resonance component having stable characteristics in which the terminal resonance is suppressed to suppress the generation of spurious vibrations and the characteristics do not change even when an external shock is applied.

Another object of the present invention is to provide an inexpensive piezoelectric resonance component which has stable characteristics such as suppressing terminal resonance and improving impact resistance, while suppressing increase in manufacturing cost and assembly error due to increase in assembly man-hours. To do.

[0015]

A piezoelectric resonance component of the present invention comprises a piezoelectric element having electrodes formed on both principal surfaces thereof for oscillating vibration, and a protrusion for holding the piezoelectric element in contact with the electrodes on one side. In the piezoelectric resonance component including the terminal plate formed in (1), an elastic body is attached to a portion of the one surface of the terminal plate excluding the protruding portion.

[0016]

According to the piezoelectric resonance component of the present invention, the elastic member is attached to a portion of the terminal plate on which the protrusion is formed, excluding the protrusion, so that the piezoelectric element is transmitted from the piezoelectric element to the terminal plate through the protrusion. These vibrations are absorbed by these elastic bodies, and the terminal resonance is damped (damped). Therefore, spurious vibration due to terminal resonance does not occur and the characteristics of the piezoelectric resonance component fluctuate, and even if an external impact is applied, the protrusion does not shift and the resonance characteristic does not change.

Further, since it is only necessary to attach the elastic body to the surface of the terminal plate on the side of the projecting portion excluding the projecting portion, the overall thickness of the terminal plate is increased as compared with the conventional piezoelectric resonance component. There is also no problem that the size of the piezoelectric resonance component becomes large, or that the number of components or the number of component assembling steps increases, leading to an increase in manufacturing cost or the possibility of assembly error.

Therefore, according to the piezoelectric resonance component of the present invention,
It is possible to provide an inexpensive piezoelectric resonance component having stable characteristics that does not change due to terminal resonance or external vibration.

[0019]

EXAMPLES The piezoelectric resonance component of the present invention will be described in detail below based on specific examples of piezoelectric filters. The present invention is not limited to the following examples, and various modifications may be made without departing from the gist of the present invention.

FIG. 1 is a sectional view showing the structure of an embodiment of the piezoelectric resonance component of the present invention. In the piezoelectric resonance component 42 of FIG. 1, 43 and 44 are series resonators as a piezoelectric element, and 45 and 46 are parallel resonators as a piezoelectric element. Electrodes (not shown) are formed. 47 to 52 are terminal plates, and 53 is a U-shaped terminal plate. Terminal boards 47-52 and U-shaped terminal boards
53 is a protrusion 47b at the center of each plate-shaped portion 47a to 53a.
~ 53b are formed thereby holding the series resonators 43,44 and the parallel resonators 45,46 as shown. Further, the terminal plates 47, 49, 51, 52 have lead-out portions 47c, 49c, 51c, 52c for connection with an external circuit,
In the piezoelectric resonance component 42, 47c is an input terminal, 51c is an output terminal, and 49c and 52c are ground terminals.

Reference numerals 54 to 57 are elastic bodies, and in this example, the terminal plates 48, 50, 51 excluding the protrusions and the plate-shaped portion 48 of the U-shaped terminal plate 53.
It is adhered to the main surface (one surface on which the protrusion is formed) on the front side of a, 50a, 51a, 53a by coating or the like. Further, 58 is an insulating spacer, and 59 is a spring for applying a holding pressure to each terminal plate 47-53 holding the piezoelectric elements 43-46.
Then, these are incorporated in the case 60 and sealed by the lid 61 to form the piezoelectric resonance component 42.

The electrical equivalent circuit of the piezoelectric resonance component 42 having such a structure is as shown in FIG. In the figure, the portions corresponding to the respective constituent members in FIG. 1 are designated by the same reference numerals.

According to the piezoelectric resonance component 42 of this example, the piezoelectric elements 43 to 46 are formed by the elastic bodies 54 to 57 attached to the front main surfaces of the U-shaped terminal plate 53 and the terminal plates 48, 50 and 51. Vibrations from the U to the U-shaped terminal plate 53 and the terminal plates 48, 50 and 51 are absorbed, so that the terminal resonance can be damped. That is, the vibrations from the series resonator 43 and the parallel resonator 45 are absorbed by the elastic bodies 54 and 55, and the vibrations from the series resonator 44 and the parallel resonator 46 are absorbed by the elastic bodies 56 and 57, respectively, to dampen the terminal resonance. Let Therefore, spurious vibration does not occur in the series resonators 43 and 44 and the parallel resonators 45 and 46, and the characteristics thereof do not change even when a shock is applied to the piezoelectric resonance component 42.

In attaching the elastic body to the terminal plate, in addition to the structure of the piezoelectric resonance component 42, it may also be attached to the main surface on the front side of the terminal plate other than those illustrated, or the main surface on the front side. You may combine the terminal board adhered to and the terminal board adhered to the back main surface. In addition, elastic bodies may be attached to both main surfaces of the main surface on the front side and the main surface on the back side of the terminal plate,
In addition, an elastic body may be appropriately arranged as desired.

Series resonators 43 and 44 and parallel resonators 45 and 46
Is a piezoelectric element using the spreading vibration mode,
A piezoelectric substrate made of, for example, an electrode of silver or the like formed by a method such as baking or vapor deposition / sputtering is used. The size is appropriately selected according to the desired characteristics, but for a resonance frequency of 455 kHz, one having a size of about 5 mm on a side is usually used.

The terminal plates 47 to 52 and the U-shaped terminal plate 53 are manufactured from a plate material made of a material such as copper alloy and having a thickness of about 0.1 to 0.2 mm by a method such as press forming. The size of each plate-shaped part is usually about 5 mm on a side,
A protrusion with a size of about 0.6 to 1.0 mmφ is formed in the center by a method such as press forming, and a draw-out portion with a width of about 1 mm and a length of about 5 mm is also formed at the end by press forming. It is formed by the method of.

The elastic bodies 54 to 57 are preferably made of a resin material such as epoxy resin or a rubber material, or a metal material such as silver (Ag) or lead (Pb). By a method such as sputtering, the surface of the terminal plate on the main surface except the protrusions is attached.

When a metal material is used for the elastic bodies 54 to 57, the thickness thereof is preferably 1.5 μm or more, and if it is less than this, the effect of absorbing vibration cannot be obtained.

When a resin material or a rubber material is used for the elastic bodies 54 to 57, its thickness is preferably about 10 to 200 μm.

The elastic body used in the piezoelectric resonance component of the present invention is
Among the above materials, a material having a low elastic modulus is preferable because it is easier to absorb the vibration of the terminal plate, and it is preferable to use a material having an elastic modulus of 5,000 kg / mm ² or less.

The insulating spacer 58 is used to avoid a short circuit between the electrodes of the piezoelectric element 45 when making the circuit connection shown in FIG. 2, and the material thereof is made of a material such as Teflon resin or silicone rubber having an elastic modulus. Low resin is used. The dimensions are usually about 5 mm on a side and 0.1 m in thickness.
It is about m.

The spring 59 is used for holding each piezoelectric element by applying an appropriate pressure to each terminal plate, and is usually a bowl shape made of a spring material such as phosphor bronze, and its dimension is one side. The thickness is set to about 5 mm and the thickness is about 0.1 mm.
Due to the spring pressure of the spring 59, the series resonator, the parallel resonator, and each terminal plate are pressed against the inner wall of the case 60 and housed / fixed in the internal space.

The case 60 and the lid 61 are for fixing and sealing each piezoelectric element and each terminal plate, and the material thereof is PBT, PPS, liquid crystal polymer or the like. These materials have a low elastic modulus (approx. 800 kg /
mm ² ), it is possible to absorb the vibration of the terminal plate without attaching an elastic body to the terminal plate in contact with the case. That is, the terminal plate 47 absorbs vibrations in the case 60, the terminal plate 49 and the U-shaped terminal plate 53 in the insulating spacer 58, and the terminal plate 52 in the case 60 via the spring 59. Therefore, in this case, it is not necessary to attach an elastic body to the front main surface or the back main surface of these terminal boards.

Then, the series resonator, the parallel resonator, the terminal plate, the insulating spacer, and the spring are housed in the case, and the case 60 and the lid 61 are sealed and joined with epoxy resin or the like to seal the internal space. By doing so, the piezoelectric resonance component 42 is completed.

The piezoelectric resonance component of the present invention having the above structure
According to 42, the vibration from the piezoelectric element to the terminal plate is absorbed by the elastic body attached to at least one of the main surfaces of the terminal plate excluding the protruding portion, and also by the insulating spacer and the case, to dampen the terminal resonance. In addition to being able to absorb the impact applied from the outside, it becomes a piezoelectric resonance component 42 having stable characteristics excellent in impact resistance without changing resonance characteristics.

Next, specific examples of the piezoelectric resonance component of the present invention will be described. The piezoelectric resonance component A of the present invention having the structure shown in FIG. 1 was manufactured as follows. First, length 5 mm x width 5 mm x thickness 1.2 mm and 0.35 mm made of PZT
Electrodes made of silver and having a thickness of 8 μm were formed on both main surfaces of the piezoelectric substrate by baking to produce a series resonator and a parallel resonator.

Next, a terminal plate and a U-shaped terminal plate were produced from the plate materials made of phosphor bronze and having a thickness of 0.15 mm and 0.1 mm by press forming. Here, the size of the plate-shaped portion of the terminal plate was set to 5 mm × 5 mm, and a protrusion having a size of 0.8 mmφ was formed by press forming in the center thereof. In addition, a lead-out portion having a width of 0.8 mm and a length of 3.5 mm was formed on the terminal plate having the lead-out portion by press forming. Of these terminal boards, terminal boards 48, 50, 51
Also, the U-shaped terminal plate 53 is made of epoxy resin on the main surface of the front side excluding the protrusions and has a thickness of approximately 0.1 mm and a side of 5 mm
An elastic body having an area of 1 was applied by coating.

As the insulating spacer, a length of 5 mm made of Teflon resin, a width of 5 mm and a thickness of 0.1 mm is prepared, and the spring made of phosphor bronze has a length of 5 mm.
A bowl-shaped product with dimensions of width 5 mm and thickness 0.1 mm was prepared. Furthermore, as a case, the length of PBT is 6.5.
mm x width 6.4 mm x height 6.3 mm (outside dimensions), length 5.5 m
m × width 5.1mm × height 5.2mm (inner size) made of paper as a lid, length 5.5mm × width 5.1mm × thickness 0.2m
I prepared m.

Then, the series resonator, parallel resonator, and
The combination of the terminal plate, the U-shaped terminal plate, the insulating spacer, and the spring was assembled in the case, and the lid was joined and sealed with an epoxy resin to obtain the piezoelectric resonance component A of the present invention. The design value of the characteristic of this piezoelectric resonance component A is GD
T (group delay time) deviation 10 μsec or less (450 ± 2 kHz
Within).

On the other hand, a piezoelectric resonance component B of a comparative example having the same design values of the characteristics was also manufactured in the same manner as described above except that the terminal plate not coated with the elastic body was used.

For these piezoelectric resonance components A and B, a network analyzer (gain / phase analyzer) is used.
The initial characteristics were measured by. The results are shown in FIGS. 6 and 7.

FIG. 6 is a diagram showing the characteristics of the piezoelectric resonance component A. In the figure, the horizontal axis represents the frequency (kHz), the vertical axis represents the attenuation [ATT] (dB) on the right side and the left side on the left side. It represents the group delay time [GDT] (μsec). And
The initial characteristics were the results as shown by the solid line of A1 in the ATT and the solid line of G1 in the GDT in the same figure. Also,
FIG. 7 is a similar diagram showing the characteristics of the piezoelectric resonance component B,
The initial characteristic is that the ATT is the solid line of A3 in the figure and is GD
The result was the same as that shown by the solid line of G3. As can be seen from these results, no significant difference was observed between the two in the initial characteristics.

Next, for the piezoelectric resonance components A and B,
An aluminum weight having a weight of 15 g from 3 cm above the case was naturally dropped three times to give an impact, and the characteristics after the impact test were evaluated in the same manner as above. The results are also shown in FIGS. 6 and 7.

The characteristics of the piezo-resonant component A after the impact test are shown in FIG. 6 in which ATT is the dotted line A2 in the figure and GDT is the same as G.
The results are shown by the dotted line in Fig. 2, and as can be seen from the figure, almost no difference from the initial characteristics was seen.

On the other hand, the characteristics of the piezoelectric resonance component B after the impact test are shown by ATT in FIG. 7 by the dotted line A4 in FIG.
T is the same result as shown by the dotted line of G4, and as can be seen from the figure, DIP occurs due to spurious due to resonance of the terminal in the GDT with respect to the initial characteristics, and the GDT deviation deteriorates by 15 μsec. The result is that a ripple of about 1 dB is generated. From this, it was confirmed that the piezoelectric resonance component A of the present invention had stable characteristics with excellent impact resistance.

From the above results, according to the piezoelectric resonance component of the present invention, the total thickness of the terminal plate is not increased, the number of large size components is not increased, and the number of assembly steps is increased. Moreover, it was confirmed that the terminal resonance can be suppressed to suppress the generation of spurious vibrations, and that the characteristics do not change even when an external shock is applied, and stable characteristics can be obtained.

Further, since the number of parts required for assembly does not increase, it is possible to suppress an increase in manufacturing cost and assembly error due to an increase in the number of assembly steps.

[0048]

As described above in detail, according to the present invention, in a piezoelectric resonance component having a terminal plate having a protrusion formed on one surface thereof, an elastic body is attached to one surface of the terminal plate excluding the protrusion. As a result, the terminal resonance is suppressed, the generation of spurious vibrations is suppressed, and the external impact is applied without increasing the number of parts having large thickness and size of the terminal board and increasing the number of assembling steps. However, it was possible to provide a piezoelectric resonance component having stable characteristics, whose characteristics did not change.

Further, according to the present invention, since the number of parts required for assembly does not increase, it is possible to suppress an increase in manufacturing cost and an assembly error due to an increase in assembly man-hours, thereby suppressing terminal resonance and improving resistance. It has been possible to provide an inexpensive piezoelectric resonance component having improved shock resistance and stable characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an embodiment of a piezoelectric resonance component of the present invention.

FIG. 2 is an equivalent circuit diagram of an embodiment of the piezoelectric resonance component of the present invention.

FIG. 3 is a sectional view showing a part of a configuration of a conventional piezoelectric resonance component.

FIG. 4 is a cross-sectional view showing the configuration of another conventional piezoelectric resonance component.

FIG. 5 is a cross-sectional view showing the configuration of another conventional piezoelectric resonance component.

FIG. 6 is a diagram showing a resonance characteristic of a piezoelectric resonance component in an example of the present invention.

FIG. 7 is a diagram showing a resonance characteristic of a piezoelectric resonance component in a comparative example of the present invention.

[Explanation of symbols]

 42 ・ ・ ・ ・ Piezoelectric resonance component 43,44 ・ ・ ・ ・ ・ Series resonator (piezoelectric element) 45,46 ・ ・ ・ Parallel resonator (piezoelectric element) 47〜52 ・ ・ ・ ・ ・ Terminal Plate 53 ... U-shaped terminal plate 47b-53b ... Projection 54-57 ... Elastic body

Claims (1)

[Claims] 1. A piezoelectric resonance component comprising: a piezoelectric element having electrodes formed on both main surfaces thereof and vibrating in a spreading manner; and a terminal plate having a protrusion on one surface for holding the piezoelectric element in contact with the electrodes. A piezoelectric resonance component, wherein an elastic body is attached to a portion of the one surface of the terminal plate excluding a protrusion.