JPH04259108A - Piezoelectric component - Google Patents

Abstract

PURPOSE:To obtain the small sized piezoelectric component with an excellent spurious characteristic by making the distance of adjacent resonators small. CONSTITUTION:Two piezoelectric elements 100a, 100b formed by forming two exciting electrodes 2, 3 and 4, 5 respectively to a 1st major side of rectangular piezoelectric plates 1a and 1b and by forming opposite electrodes to the said two exciting electrodes onto a 2nd major side are adhered between two seal plates 101, 102. Thus, since the piezoelectric elements 100a, 100b are separated by the piezoelectric plates 1a, 1b, the vibration of the both is not interfered mutually even when the distance between the two resonators is decreased and the spurious characteristic is not deteriorated. Thus, the entire piezoelectric element is made small without deteriorating the spurious characteristic.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to piezoelectric components used in filters and the like.

0002

2. Description of the Related Art A component in which a plurality of sets of excitation electrodes and counter electrodes are provided on both principal surfaces of a piezoelectric plate to form a multistage resonator is used in filters and the like. Examples of this type of piezoelectric component are shown in FIGS. 6 and 7. FIG. 6 is a plan view of the piezoelectric plate (A
) shows the electrode pattern on the first main surface, and (B) shows the electrode pattern on the second main surface. On the first principal surface of the piezoelectric plate 1, excitation electrodes 2, 3, 4, and 5, a capacitor electrode 6, and extraction electrodes 7 and 8 of each electrode are formed. The second piezoelectric plate 1
A counter electrode 10 is formed on the main surface to face the excitation electrodes 2 and 3, a counter electrode 11 is formed to face the excitation electrodes 4 and 5, and a counter electrode 10 is formed to face the capacitor electrode 6. 11 is provided.

[0003] In this way, a piezoelectric element 100 is constructed which includes two sets of multimode resonators and a capacitor on a single piezoelectric plate. FIG. 7 is an exploded perspective view of the entire piezoelectric component.
The piezoelectric element 100 is sealed between two sealing plates 101 and 102.

0004

As described above, a piezoelectric component in which a plurality of sets of resonators are formed on a single piezoelectric plate has a feature that the entire component can be miniaturized. However, in response to the recent increase in component mounting density on wiring boards, there is a demand for further miniaturization of the entire component. Since the dimensions of the excitation electrode and the counter electrode are determined by filter characteristics such as the resonance frequency, it is necessary to narrow the distance between the two resonators in order to downsize the entire component. However, as a result, there is a problem in that the vibrations of adjacent resonators interfere with each other, particularly deteriorating spurious characteristics, and there is a limit to miniaturization while maintaining characteristics.

An object of the present invention is to provide a piezoelectric component that solves the above-mentioned problems by making it possible to reduce the distance between adjacent resonators within the piezoelectric component without deteriorating spurious characteristics.

[0006]

[Means for Solving the Problems] The piezoelectric component of the present invention includes:
Each of the rectangular piezoelectric plates has an excitation electrode and an extraction electrode extending the excitation electrode to the edge on the first main surface, and a counter electrode facing the excitation electrode and an extraction electrode that extends the excitation electrode to the edge on the second main surface. a plurality of piezoelectric elements each having a lead-out electrode extending to a portion thereof, each having an external electrode connected to the lead-out electrode, arranging the plurality of piezoelectric elements and sandwiching each piezoelectric element from both principal surfaces; It is characterized by being composed of two sealing plates.

[0007]

[Function] In the piezoelectric component of the present invention, each piezoelectric element is provided with an excitation electrode on the first main surface of the rectangular piezoelectric plate and an extraction electrode that pulls out the excitation electrode to the end edge, and the excitation electrode is provided on the second main surface of the piezoelectric component. A piezoelectric device equipped with a counter electrode facing the electrode and an extraction electrode that extends the counter electrode to the edge is used, and a plurality of piezoelectric elements are arranged and sandwiched between two sealing plates.

By using piezoelectric elements divided for each set of resonators in this manner, mutual interference of vibrations through the separated piezoelectric plates is eliminated. Therefore, even if the spacing between resonators becomes narrow when arranging small rectangular piezoelectric plates, there is almost no mutual interference of vibrations, and as a result, an overall compact piezoelectric component can be obtained without deteriorating spurious characteristics. be able to.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a piezoelectric component according to an embodiment of the present invention is shown in FIGS. 1 to 4.

FIGS. 2 and 3 are diagrams showing two types of piezoelectric elements, in which (A) is a plan view of the first principal surface, and (B) is a plan view of the electrode provided on the second principal surface. It is a diagram seen from the side. In FIG. 2, 1a is a rectangular piezoelectric plate, 2 and 3 are a pair of excitation electrodes, 6a is a capacitor electrode, 7 is an extraction electrode that draws out the excitation electrode 2 to the edge of the piezoelectric plate, and 9a is an excitation electrode 3. and a lead-out electrode that leads the capacitor electrode 6a to the edge of the piezoelectric plate. Further, reference numeral 10 denotes a counter electrode that faces the pair of excitation electrodes 2 and 3 via the piezoelectric plate 1a;
Reference numeral 2a denotes an extraction electrode that faces the capacitor electrode 6a and draws out the counter electrode 10 to the edge of the piezoelectric plate.

In FIG. 3, 4 and 5 are a pair of excitation electrodes, and 6
b is a capacitor electrode, 8 is a lead-out electrode for drawing out the excitation electrode 4 to the edge of the piezoelectric body plate, and 9b is a lead-out electrode for drawing out the excitation electrode 5 and the capacitor electrode 6b to the edge of the piezoelectric body plate. Further, 11 is a counter electrode that faces the pair of excitation electrodes 4 and 5 via the piezoelectric plate 1b, and 12b is a lead-out electrode that faces the capacitor electrode 6b and draws out the counter electrode 11 to the edge of the piezoelectric plate. be.

As is clear from a comparison of FIGS. 2 and 3, the electrode patterns of these two piezoelectric elements are line symmetrical, and in the orientation shown in both figures, the piezoelectric element 100a is placed on the left side, 100
By arranging b on the right side, the extraction electrode 9
a, 9b and 12a, 12b can be placed close to each other.

FIG. 1 is an exploded perspective view showing the overall structure of the piezoelectric component. In FIG. 1, 101 and 102 are sealing plates that seal the two types of piezoelectric elements 100a and 100b, respectively. As shown in the figure, there are two
The different types of piezoelectric elements 100a and 100b are arranged butted against each other as shown in the figure, and a sealing plate 102 is attached using an adhesive.
Paste it on. After that, further piezoelectric elements 100a, 1
A sealing plate 101 is bonded to the upper surface of 00b using an adhesive. Incidentally, recesses are formed on the inner surfaces of the sealing plates 101 and 102 to ensure a vibration space for the two resonators, similar to the conventional example shown in FIG. Or piezoelectric element 1
A vibration space may be secured by an adhesive layer for bonding 00a and 100b together.

FIG. 4 is an external perspective view of the piezoelectric component. In the figure, 13 to 16 are external electrodes, respectively. The external electrode 13 is electrically connected to the extraction electrode 7, and the external electrode 14 is electrically connected to the extraction electrode 8. Further, the external electrode 15 is electrically connected to the extraction electrodes 12a and 12b, and
The extraction electrodes 12a and 12b are electrically connected. Further, the external electrode 16 is connected to the extraction electrodes 9a and 9b, and electrically connects the extraction electrodes 9a and 9b. Note that these external electrodes are formed, for example, by mask sputtering Monel metal and then electrolytic plating or solder dipping.

With the above structure, the excitation electrodes 3 and 5, the capacitor electrodes 6a and 6b, and the extraction electrodes 12a and 12b are electrically connected, respectively. Therefore, equivalently, a piezoelectric component including two multimode resonators and one capacitor is configured.

In the above embodiment, a two-element type piezoelectric component was used as an example, but it is also possible to use a multi-element type piezoelectric component. An example of a three-element type is shown in FIG.

FIG. 5 is a perspective view showing three piezoelectric elements 100a, 100b, and 100c arranged on one sealing plate 102 and bonded together. In this way, a plurality of piezoelectric elements each having one set of excitation electrodes and one set of capacitor electrodes may be used.

[0018] Regardless of whether the piezoelectric component is a two-element type or a two-element or more type piezoelectric component, the sealing plate and the piezoelectric element may be manufactured in the form of a mother substrate, respectively, and then bonded together and then cut.

[0019]

[Effects of the Invention] According to the present invention, since adjacent resonators are separated by the piezoelectric plates themselves, there is almost no mutual interference of vibrations, and spurious characteristics hardly worsen even if the distance between the resonators is shortened. I have nothing to do. Therefore, a piezoelectric component that is small and has excellent spurious characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a piezoelectric component according to a first embodiment.

FIG. 2 is a plan view showing the electrode shape of the piezoelectric element used in the piezoelectric component, in which (A) shows the electrode provided on the first main surface, and (B) shows the electrode provided on the second main surface. Each represents an electrode.

FIG. 3 is a plan view showing the electrode shape of another piezoelectric element used in the same piezoelectric component, in which (A) is an electrode provided on the first main surface, and (B) is an electrode provided on the second main surface. Each electrode is represented by a

FIG. 4 is an external perspective view of the piezoelectric component according to the first embodiment.

FIG. 5 is a perspective view of the main parts of a piezoelectric component according to a second embodiment.

FIG. 6 is a plan view showing the electrode shape of a piezoelectric element used in a conventional piezoelectric component, in which (A) is an electrode provided on the first main surface, and (B) is an electrode provided on the second main surface. represents each electrode.

FIG. 7 is an exploded perspective view of a conventional piezoelectric component.

[Explanation of symbols]

1, 1a, 1b Piezoelectric body plates 2, 3, 4, 5 Excitation electrodes 6, 6a, 6b Capacitor electrodes 7, 8, 9, 9a, 9b Extraction electrodes 10, 11 Counter electrodes 12, 12a, 12b Extraction electrodes 13, 14 , 15, 16 external electrodes 100, 100a, 100b piezoelectric elements 101, 10
2 Sealing plate

Claims (1)

[Claims] 1. Each rectangular piezoelectric plate is provided with an excitation electrode and an extraction electrode extending the excitation electrode to an edge on a first main surface thereof, and a counter electrode facing the excitation electrode and an extraction electrode provided on the second main surface thereof. A plurality of piezoelectric elements each having an extraction electrode that extends a counter electrode to an edge, and an external electrode connected to each of the extraction electrodes, the plurality of piezoelectric elements are arranged, and each piezoelectric element has two main A piezoelectric component consisting of two sealing plates that are sandwiched from the surface.