JPS627213A - Piezoelectric resonance component - Google Patents

Abstract

PURPOSE:To miniaturize a external size, to make a size constant and to eliminate a temperature change in a frequency characteristic by overlapping a spacer and an element to form a laminator, connecting a lead electrode to one terminal of the element and a lead terminal to the other terminal. CONSTITUTION:Plural elements 3 each arranged with one set of filter elements on a piezoelectric substrate 1 and a spacer 4 arranged between the elements 3 and on the outer face of an outer element 3 are overlapped, the corresponding ends of lead electrodes 12, 14 at one end of each element 3 is connected by a short terminal 10, and an input lead terminal 7, an output lead terminal 8 and an earth lead terminal 9 are connected to the lead electrodes 12, 14 of the other terminal to form a laminator 5. In containing the laminator 5 in a case 6, the terminals 7-9 are projected externally from the opening. Then the opening is packed by a sealing agent 17 to complete the component.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a piezoelectric resonant component, and more particularly to a combination of three-terminal piezoelectric resonant elements and a package structure thereof.

<Prior Art> Piezoelectric resonant components using three-terminal dual-mode energy-confined vibration are used, for example, in filters, discriminators in FM demodulation circuits, and the like.

The conventional piezoelectric resonant component described above employs the application of energy confinement theory to arrange a plurality of filter elements each consisting of divided vibrating electrodes and a common vibrating electrode facing each other on a single piezoelectric substrate made of ceramic or the like. The piezoelectric substrate is further coated with an exterior body coated by dip coating, and a vibration space is formed on a surface of the exterior body corresponding to each vibrating electrode.

<Problems to be Solved by the Invention> By the way, when the exterior finish is done by dip coating, the external shape is large and the dimensions are not constant, making chucking difficult when automating the mounting on the wiring board, and the mounting is a major obstacle to automation.

In addition, to secure the vibration space, wax is applied to the surface of the piezoelectric substrate, then dip coating is applied, and then heat treatment is performed to absorb the wax into the exterior resin, forming a cavity in the vibrating part. .

Although the method for forming the vibration space described above can be manufactured at low cost, there is a problem in that stress due to thermal expansion and contraction of the exterior resin causes piezoelectric force to act on the piezoelectric substrate, causing temperature changes in the frequency characteristics of the filter.

Furthermore, in a structure in which multiple filter elements are provided on a single piezoelectric substrate, there are local errors in the thickness of the piezoelectric substrate, and the differences in characteristics of each filter element due to this error affect the overall characteristics, so the filter characteristics There is a problem that variations occur.

This invention was made in order to solve various problems as mentioned above, and it is possible to reduce the size of the external shape, prevent the foot from moving,
Moreover, it is an object of the present invention to provide a piezoelectric resonant component whose frequency characteristics do not change with temperature and whose overall characteristics do not vary.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a structure in which a divided vibrating electrode and an extraction electrode of each electrode are provided on one surface of a rectangular piezoelectric substrate. A common vibrating electrode and its lead electrodes are provided on the other surface so that the vibrating electrodes on both sides face each other with the piezoelectric substrate in between, and each lead electrode is drawn out in a symmetrical manner that reaches two opposing sides of a pair of piezoelectric substrates. A laminate of a plurality of elements and a plurality of spacers stacked together with the elements so as to overlap between each element and on the outer surface of the outer element, and a vibration cavity is formed on the surface facing the vibration electrode of the element, and the element and the spacer. The stack consists of a case that houses the elements, and lead terminals that are connected to the lead electrodes of the elements in the laminate so as to protrude in the same direction. The opening of the case from which the lead terminals are pulled out is sealed.

<Operation> Spacers and elements are stacked alternately in a predetermined number to form a laminate, and the corresponding lead electrodes of each element in this laminate are connected at one end of the element with a short terminal, and at the other end of the element. The piezoelectric resonant component is assembled by connecting lead terminals to the extraction electrodes and pulling them out in the same direction, storing this element in a case, and then sealing the opening of the case from which the lead terminals have been pulled out.

<Example> Hereinafter, an example of the present invention will be described based on the accompanying drawings.

As shown in the figure, the piezoelectric resonant component of the present invention includes a plurality of elements 3 in which a set of filter cords 2 are arranged on a piezoelectric substrate 1 made of ceramic or the like, and the areas between each element 3 and the outer surface of the outer element. A plurality of spacers 4 arranged one on top of the other, a case 6 that houses the stacked body 5 of the elements 3 and spacers 4, lead terminals 7, 8, 9 connected to the extraction electrodes of the outer elements, and correspondence between each element 3. It is composed of terminals 1 to 10 that connect the lead electrodes.

The element 3 has a divided vibrating electrode 11.11 in the center of one side of a piezoelectric substrate 1 formed in a rectangular shape, and a common vibrating electrode 13 on the other side of the lead electrode 12.12 of each electrode. The extraction electrode 14 is connected to the vibrating electrodes 11 and 11 on both sides.
and 13 are provided to face each other with the piezoelectric substrate 1 in between, and the lead electrodes 12, 12 and 14 on both sides are drawn out symmetrically so as to reach one set of two opposing sides of the piezoelectric substrate 1. used as is.

The spacer 4 is made of an insulating material such as synthetic resin, and the piezoelectric substrate 1
When overlapped with the element 1, a vibration space 15, which is slightly larger than the vibration electrode, is formed at a position corresponding to the vibration electrode 11.11 or 13, and each extraction electrode 12. A notch 16 is provided at a position corresponding to the end of the lead electrode 12 or 14, so that lead terminals and short terminals can be soldered to the extraction electrodes 12 and 14 without any problem.

The vibration space 15 may be formed by a recessed step in addition to a through hole, and in the case of the spacer 4 sandwiched between the elements 3, the recessed step must be provided on both surfaces thereof.

Each of the elements 3 and the spacer 4 are stacked and bonded together to form a laminate 5, and on one side of the laminate 5, the ends of the corresponding extraction electrodes of the adjacent elements 3 are connected to each other. Connect with short terminal 10, and then connect with the third
As shown in the figure, lead terminals 7.8.9 are connected to the ends of predetermined extraction electrodes on the other side of the laminate 5.

As mentioned above, the filter elements of each element 3 are connected in series by the shorting terminal 10, and each lead terminal 7.8.9 for input and output grounding is led out in the same direction.

The case 6 is made of synthetic resin or the like and is formed into a box shape with one end open so that the laminate 5 can fit therein.
When the laminate 5 is housed in the case 6, each lead terminal 7.
8.9 protrudes outside from the opening.

After housing the laminate 5, the opening of the case 6 is sealed by filling it with a sealing material 17 as shown in FIG.

The piezoelectric resonant component of the present invention has the above-mentioned configuration, in which a plurality of elements 3 (three in the illustrated case) and spacers 4 arranged between each element and on the outer surface of the outer element are stacked, and each element 3 is Connect the corresponding end of the extraction electrode on one end side with a short terminal 10 as shown in FIG.
Furthermore, the input lead terminal 7 is connected to the extraction electrode 12.14 on the other end side.
The output lead terminal 8 and the ground lead terminal 9 are connected to form a laminate 5 as shown in FIG.
After the piezoelectric resonant component is housed inside, the opening is sealed to complete the piezoelectric resonant component as shown in FIG.

<Effects> As described above, according to the present invention, the above configuration provides the following effects.

(I) The laminate formed by stacking the vibrating element and the spacer is housed in a case, and the mouth of the case from which the lead terminals are pulled out is sealed, so the exterior can be formed by the case, and thermal expansion similar to a dip exterior is avoided. As a result, stress is not applied to the piezoelectric substrate, and the frequency characteristics are not affected by temperature changes.

(I) The exterior can be formed by a case, and due to improved dimensional accuracy, automatic mounting on wiring boards can be easily implemented.

(I) The exterior can be formed by a case, making it possible to reduce the overall size.

■ Since it is constructed using a small number of elements in which single elements are formed, by selecting and using elements with uniform characteristics, there is no variation in overall characteristics, and performance can be significantly improved.

(■ By selecting and using elements with uniform characteristics, there is no variation in overall characteristics, there is no occurrence of defective elements, and it is possible to reduce costs by improving yield.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing the connected state of elements in a piezoelectric resonant component according to the present invention, Fig. 2 is a perspective view of an element used in the same, Fig. 3 is a side view of a laminate, and Fig. 4 is a piezoelectric resonant component. Required for cross-sectional views of parts.

Claims (1)

[Claims] A divided vibrating electrode and an extraction electrode for each electrode are placed on one side of a rectangular piezoelectric substrate, and a common vibrating electrode and its extraction electrode are placed on the other side so that the vibrating electrodes on both sides face each other with the piezoelectric substrate in between. a plurality of elements, each of which is provided in a piezoelectric substrate, and whose respective extraction electrodes are symmetrically extended to reach two opposing sides of a pair of piezoelectric substrates;
A case that stores multiple spacers stacked together with the elements so as to overlap between each element and the outer surface of the outer element, and with a vibration cavity formed on the surface facing the vibration electrode of the element, and a laminate of the elements and spacers. and lead terminals connected to the lead electrodes of the elements in the laminate so as to protrude in the same direction, and the laminate is housed in a case with the corresponding lead electrodes of each element connected by short terminals, A piezoelectric resonant component that seals the opening of the case where the lead terminal is pulled out.