JPH06252687A - Piezoelectric resonator element - Google Patents

Abstract

(57) [Summary] [Structure] In a piezoelectric resonant element 11 having electrodes 12a and 12b on both sides of a piezoelectric substrate, the piezoelectric resonant element 11 includes a vibrating portion 14, a holding portion 16, and coupling portions 15a and 15b. A piezoelectric resonance element in which 14 and a holding portion 16 which is a substantially immovable portion are coupled by coupling portions 15a and 15b. As the vibrating portion 14 is securely held by the coupling portions 15a and 15b and the holding portion 16, there is a possibility that a shock such as a drop may cause inconveniences such as detachment of the piezoelectric resonance element 11 and occurrence of a shift in resonance frequency. Absent. Further, in the piezoelectric component using the piezoelectric resonance element 11 according to the present invention, the number of components is small and the number of assembling steps can be reduced, so that the total cost can be reduced and the piezoelectric component can be parallel to the protective case. Since the piezoelectric resonance element is installed, the height and the size of the piezoelectric resonance element can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonance element, and more particularly to a piezoelectric resonance element used as a resonator, a filter, a discriminator, a delay line or the like in the fields of information processing, communication and the like.

[0002]

2. Description of the Related Art A structure made of ceramics or the like has a shape,
It has a unique mechanical resonance frequency determined by the material and so on. Piezoelectric ceramics is a conversion element for converting an electric signal and mechanical vibration, and when an AC voltage is applied, mechanical vibration having the same period as that is generated. The amplitude becomes maximum when the period matches the natural resonance frequency, and a constant frequency is selectively extracted by converting this into an electric signal again.

Inherent mechanical resonance has various vibration modes depending on the shape of the substrate, the polarization direction, the application direction of the electric signal, and the like. FIG. 9 shows a typical vibration mode used in, for example, a ceramic filter. Which vibration mode is selected depends almost on the center frequency of the filter to be realized. That is, the bending vibration mode and the length vibration mode in the LF band, the spreading vibration mode in the MF band, and HF to
In the VHF band, the energy confinement type thickness vibration mode is generally used.

When manufacturing the piezoelectric resonance element utilizing the various vibration modes described above, the problem is the method of holding the piezoelectric resonance element. That is, when holding these piezoelectric resonance elements, it is necessary to support the piezoelectric resonance elements so as not to hinder the vibration thereof and to establish electrical continuity with the electrodes. for that reason,
Many contrivances have been made in actual piezoelectric components.

Conventionally, many resonators using the LF band and the MF band utilize the spreading vibration mode (for example, Japanese Utility Model Publication No. 2-143831 and Japanese Utility Model Publication No. 2-148812). FIG. 10 shows a more detailed conceptual diagram of vibration in the case of using this spreading vibration mode. Since the vibration distribution is vibration that isotropically repeats expansion and contraction in the plane direction (XY direction), the central portion E of the piezoelectric resonance element is a node of vibration and the edge is an antinode. Therefore, when manufacturing a piezoelectric component,
The piezoelectric resonance element is supported at one point in the central portion E of the element, which serves as a node of the expanded vibration mode. Therefore, as shown in FIG. 11, the piezoelectric component using the spreading vibration mode generally has a metal sandwiching plate 4 having a protrusion at the central position of the piezoelectric resonance element 41.
The piezoelectric resonance element 41 is supported by the 2a and 42b, and is housed in the resin protective cases 43a and 43b.

[0006]

However, when the piezoelectric resonator 41 and the metal sandwiching plates 42a and 42b are housed in the resin protective cases 43a and 43b, the support points for the piezoelectric resonator 41 are easily displaced, and for example, as shown in FIG. When the support point is displaced from the central position as shown by points A to D, the frequency waveform is disturbed and sufficient oscillation cannot be obtained.

The present invention has been made in view of the above-mentioned problems, and the piezoelectric resonance element can be mechanically firmly fixed, and even if an impact such as a drop is applied, the piezoelectric resonance element is detached or the resonance frequency is shifted. It is an object of the present invention to provide a highly reliable piezoelectric resonance element that can prevent the occurrence of the above-mentioned phenomenon and can reduce the size and height of the piezoelectric component.

[0008]

In order to achieve the above object, a piezoelectric resonance element according to the present invention is a piezoelectric resonance element having electrodes on both surfaces of a piezoelectric substrate, wherein the piezoelectric resonance element includes a vibrating portion, a holding portion and a coupling portion. The vibrating portion and the holding portion, which is a substantially immovable portion, are coupled by the coupling portion.

[0009]

The above-mentioned structure is characterized in that the vibrating portion that actually vibrates when a voltage is applied and the holding portion for holding the vibrating portion are connected. That is, paying attention to the fact that there is a portion of the vibrating portion that is less likely to vibrate when a voltage is applied, so that the vibrating portion can be held in the portion of the vibrating portion that is less likely to vibrate. It is characterized in that the holding portion is integrally formed on one piezoelectric substrate. As described above, since the vibrating portion, the holding portion, and the coupling portion for coupling the two are integrally formed on one piezoelectric substrate, the metal sandwiching plate 42a, which is conventionally required, 42b and the conductive adhesives 54a and 54b are not required, and the vibrating portion is reliably held, and the impact such as a drop does not cause the inconvenience such as the separation of the piezoelectric resonance element and the deviation of the resonance frequency. .

Further, since the vibrating section is coupled to the holding section through the coupling section at a portion which is less likely to vibrate, vibration in the vibrating section is not suppressed, ripples and the like do not occur, and the piezoelectric resonance element. The characteristics as are improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a piezoelectric resonance element according to the present invention will be described below with reference to the drawings.

1A and 1B are schematic views showing a piezoelectric resonance element according to an embodiment, FIG. 1A is a perspective view of the piezoelectric resonance element, and FIG.
FIG. 3 is a front view of a piezoelectric resonance element.

In the figure, 11 indicates a piezoelectric resonance element.
The piezoelectric resonance element 11 includes a vibrating section 14, a holding section 16, and coupling sections 15 a, 1 for coupling the vibrating section 14 and the holding section 16.
5b is provided. Further, the holding portion 16 and the vibrating portion 14 are joined to the vibrating portion 14 which is hard to vibrate.
They are integrated by a and 15b. Vibrating electrodes 12a and 12b (not shown) are formed on both surfaces of the vibrating portion 14, and terminal electrodes 13a and 13b are formed on only one surface of the coupling portions 15a and 15b and the holding portion 16, respectively.
By applying an alternating current to these terminal electrodes 13a and 13b, the vibrating portion 14 having the vibrating electrodes 12a and 12b formed on both surfaces resonates.

Thus, the piezoelectric resonance element 1 according to this embodiment
1 is a vibrating portion 14, a holding portion 16, and coupling portions 15a, 15
Since b is integrally formed by molding a single piezoelectric substrate, the metal holding plates 42a,
2b is no longer necessary, and inconveniences such as the detachment of the piezoelectric resonance element 11 and the shift of the resonance frequency due to the impact such as dropping do not occur. Further, since the vibrating portion 14 is coupled to the holding portion 16 through the coupling portions 15a and 15b at the substantially immovable portion, the vibration in the vibrating portion 14 is not suppressed, ripples and the like are not generated, and the piezoelectric resonant element is formed. The characteristics of can be improved.

FIG. 2 is a schematic diagram showing each component when the piezoelectric component 10 is manufactured by using the piezoelectric resonance element 11 according to the above-mentioned embodiment and the completed piezoelectric component. FIG. It is a disassembled perspective view which shows each component, (b) is a perspective view which shows the piezoelectric component completed by assembly. 1 in the figure
Reference numerals 7a and 17b denote protective cases.
a and 17b are the holding portions 16 of the piezoelectric resonance element 11 on the periphery.
It has a support portion 19a having substantially the same width and shape and a recessed portion 19b which becomes a cavity when assembled. When assembling, as shown in FIG.
Protective cases 17a and 17b are superposed on the upper surface and the lower surface of 1 so that the three are exactly overlapped with each other, and adhered by an adhesive. The support portion 19a does not necessarily have to have the same shape as the holding portion 16, and may have a shape that allows the vibration portion 14 to freely vibrate without coming into contact with the vibration portion 14 when assembled. After the three members are stacked and bonded in this manner, the common terminal electrode 13a,
Solder electrodes 20 are provided on each side so that current can be supplied to 13b.
a and 20b are formed. These solder electrodes 20a, 20b
Is connected to another large board, such as a printed wiring board. Piezoelectric resonator 11 according to the present embodiment
Since the number of constituent parts of the piezoelectric component 10 using is smaller than that of the conventional one, and the assembling is also very simple, it is possible to automate each process at the time of manufacturing the piezoelectric component 10, thereby reducing the cost and improving the product yield. Can be planned. Further, since the flat plate-shaped piezoelectric resonance element 11 is installed in parallel with the protective cases 17a and 17b, not on the structure standing on the substrate 52 (FIG. 9), the piezoelectric component 10 can be made low-profile and compact. Can be achieved.

Next, another embodiment of the piezoelectric resonance element according to the present invention will be described. 3A and 3B are schematic views showing a piezoelectric resonance element according to another embodiment, FIG. 3A is a front view of the piezoelectric resonance element, and FIG. 3B is a rear view of the piezoelectric resonance element.

In the figure, reference numeral 21 denotes a piezoelectric resonance element,
The piezoelectric resonance element 21 includes a vibrating portion 24, a holding portion 26a,
26b and the coupling part 25a, 25b which couple | bonds the vibrating part 24 and the holding parts 26a, 26b. Further, the holding portions 26a, 26b and the vibrating portion 24 are integrated by the joining portions 25a, 25b which are joined to the immovable portion of the vibrating portion 24. The vibrating electrodes 22a, 22 are provided on both sides of the vibrating portion 24.
b is formed, and the connecting portions 25a and 25b and the holding portion 26 are formed.
a and 26b have terminal electrodes 23a, 2
3b are formed and these terminal electrodes 23a, 23b are formed.
By applying an alternating current to the vibrating electrodes 22a, 2
The vibrating portion 24 formed with 2b resonates. The difference from the piezoelectric resonance element 11 shown in FIG. 1 is that the holding portions 26a and 26b are not directly coupled to each other, but are integrally formed only via the coupling portions 25a and 25b and the vibrating portion 24. There is a point.

Also in the piezoelectric component using the piezoelectric resonance element 21 according to the present embodiment, it is possible to automate each process at the time of manufacturing the piezoelectric component as in the case described above, and it is possible to reduce the cost and improve the product yield. Further, it is possible to reduce the height and size of the piezoelectric component.

Next, another embodiment of the piezoelectric resonant element according to the present invention will be described.

FIG. 4 is a perspective view showing a piezoelectric resonance element according to another embodiment.

In the figure, 31 indicates a piezoelectric resonance element.
The piezoelectric resonance element 31 includes a vibrating portion 34, a holding portion 36a,
36b and the connecting part 35a, 35b which connects the vibrating part 34 and the holding parts 36a, 36b. Further, the holding portion 3
6a and 36b and the vibrating portion 34 are integrated by the joint portions 35a and 35b which are joined to the immovable portion of the vibrating portion 34. The vibrating electrodes 32a, 32 are provided on both surfaces of the vibrating portion 34.
b is formed, and the connecting portions 35a and 35b and the holding portion 36 are formed.
a and 36b have terminal electrodes 33a, 3
3b are formed, and these terminal electrodes 33a and 33b are formed.
By applying an alternating current to the vibrating electrodes 32a, 3
The vibrating portion 34 formed with 2b resonates. The difference from the piezoelectric resonance element 11 shown in FIG. 1 is that the holding portions 36a and 36b are not directly coupled to each other, but are coupled only via the coupling portions 35a and 35b and the vibrating portion 34. Also, since the coupling portions 35a and 35b are coupled at a part in the thickness direction of the piezoelectric resonance element 31, only a part in the thickness direction is constrained, and the other parts can freely vibrate.

Using the piezoelectric resonance element 31 according to this embodiment, a piezoelectric component can be manufactured in the same manner as the above case. When manufacturing this piezoelectric component, it is possible to automate each process of the piezoelectric component manufacturing as in the case described above, and it is possible to reduce costs and improve product yield, and further reduce the size and size of the piezoelectric component. Can be achieved.

Next, a measuring method and a result regarding resonance of the piezoelectric resonance element according to the embodiment of the present invention will be described. FIG. 5 is a perspective view showing the measured piezoelectric resonance element. The piezoelectric resonance element 100 is a vibrating part 10 of 10 mm × 10 mm × 0.53 mm.
1 and 2 mm × 5.5 mm × 0.53 mm connecting portions 102 and 103. 102c and 103c
Corresponds to a portion that is fixed during measurement, that is, a holding portion that is a substantially immovable portion. In the vibrating portion 101, the piezoelectric substrate polarized perpendicularly to the electrode surface is formed by the electrodes 101a and 10a.
It has a structure sandwiched between 1b. Coupling 102 and 1
In No. 03, lead electrodes 102a and 103b are provided on one surface and electrically connected to the electrodes 101a and 101b of the vibrating portion.

Next, the measuring jig and the measuring method used for the measurement will be described. FIG. 6 is a perspective view of a measuring jig used for measurement. The measuring jig 200 includes a glass epoxy substrate 201 of 15 mm × 35 mm and a glass epoxy substrate 2
The electrode terminals 202 and 203 are fixed to the pair of through holes provided in 01 with solders 202d and 203d. The electrode terminals 202 and 203 are made of beryllium copper, and the sample holding portions 202a and 202b and 203a and 203b and the measuring instrument side terminal portions 202c and 2 are provided.
03c. FIG. 7 is an enlarged view of the immovable portion 103c of the piezoelectric resonance element fixed to the electrode terminal 203. The sample was fixed by opening the electrode terminals 203a and 203b of the measuring jig 200 as shown in FIG. 7, and sandwiching and fixing the holding portion 103c so as to make surface contact instead of point contact. The electric signal from the electrode 101b of the vibrating portion is supplied to the lead electrode 103b provided in the coupling portion and the electrode terminal 2 of the measuring jig.
The signal is input to the measurement terminal of the impedance analyzer via 03b to 203c, and the impedance is measured.

FIG. 8 shows an example of the result of measuring the impedance characteristic. According to the present invention, it can be seen that good resonance without spurious can be obtained. As a result of the same measurement, it was confirmed that the above-described piezoelectric resonance element resonated in the range of 215 to 225 kHz.

According to the present invention, it is possible to resonate in the frequency range of 10 kHz to 10 MHz by setting the dimension to an appropriate value.

[0027]

As described in detail above, in the piezoelectric resonance element according to the present invention, in the piezoelectric resonance element having electrodes on both surfaces of the piezoelectric substrate, the piezoelectric resonance element includes a vibrating portion, a holding portion and a coupling portion. In addition, since the substantially immovable portion when the vibrating portion vibrates and the holding portion are coupled by the coupling portion, the metal sandwiching plates 42a, 42, which are conventionally required, are provided.
b is not necessary, and the vibrating portion is reliably held, and there is no inconvenience such as detachment of the piezoelectric resonance element or occurrence of deviation of resonance frequency due to impact such as dropping.

Further, in the piezoelectric resonance element according to the present invention, when a piezoelectric component using the piezoelectric resonance element is manufactured, the number of components is small because it is composed of only the piezoelectric resonance element and the protective case. Since the man-hours can be reduced, the total cost can be reduced. Moreover, since the flat plate-shaped piezoelectric resonance element is installed not in a structure standing on the substrate but in parallel with the protective case, the piezoelectric resonance element can be reduced in size. It can be placed in a dorsal position and downsized.

[Brief description of drawings]

FIG. 01 is a schematic view showing a piezoelectric resonance element according to an example of the present invention, (a) is a perspective view of the piezoelectric resonance element, and (b) is a perspective view of the piezoelectric resonance element.
FIG. 4 is a front view of a piezoelectric resonator.

FIG. 02 is a schematic diagram showing each component when assembling the piezoelectric component using the piezoelectric resonance element according to the example of the present invention and the completed piezoelectric component, and (a) is an exploded view showing each component of the piezoelectric component. FIG. 3B is a perspective view showing a piezoelectric component which is assembled and completed.

FIG. 03 is a schematic view showing a piezoelectric resonance element according to another embodiment of the present invention, (a) is a front view of the piezoelectric resonance element,
(B) is a rear view of the piezoelectric resonant element.

FIG. 04 is a perspective view showing a piezoelectric resonance element according to still another embodiment of the present invention.

FIG. 05 is a perspective view showing a piezoelectric resonance element whose resonance frequency is measured.

FIG. 06 is a perspective view showing a measuring jig used for measuring a resonance frequency.

FIG. 07 is an enlarged view showing a non-moving part of the piezoelectric resonance element fixed to the electrode terminal of the measuring jig.

FIG. 08 is a graph showing an example of a result of measuring the impedance characteristic of the piezoelectric resonance element.

FIG. 09 is a schematic view showing a typical vibration mode used for a ceramic filter.

FIG. 10 is a conceptual diagram showing a vibration distribution and an amplitude distribution regarding vibration in the case of utilizing a spreading vibration mode and a length vibration mode.

FIG. 11 is a perspective view showing a piezoelectric component using a conventional spreading vibration mode.

[Explanation of sign]

11, 21, 31 Piezoelectric resonance element 12a, 12b, 22a, 22b, 32a, 32b Vibration electrode 13a, 13b, 23a, 23b, 33a, 33b Terminal electrode 14, 24, 34 Vibration part 15a, 15b, 25a, 25b, 35a , 35b Coupling portion 16, 26a, 26b, 36a, 36b Holding portion

Claims (1)

[Claims] 1. A piezoelectric resonance element having electrodes formed on the surface of a piezoelectric substrate, wherein the piezoelectric resonance element includes a vibrating portion, a holding portion, and a coupling portion, and the holding portion is a substantially immovable portion with the vibrating portion. A piezoelectric resonance element, wherein and are coupled by the coupling portion.