JPS6125251B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric device characterized by a support structure for a piezoelectric resonant plate.

There is a piezoelectric resonator that utilizes areal vibration or radial vibration as shown in FIG. While being supported in the vicinity thereof, the electrodes 6 and 7 provided on the plate 1 and the metal terminals 2 and 3 are electrically connected to each other.
In this case, the metal terminals 2 and 3 are generally structured to have spring properties to ensure support and electrical continuity, but due to structural and material limitations, vibrations and It has been difficult to improve impact beyond a certain level. In other words, in order to ensure support,
If the contact surfaces of the projections 4 and 5 to the electrodes 6 and 7 are widened, changes in the resonance frequency, anti-resonance frequency, resonance resistance, and anti-resonance resistance become too large to be practical.

A first object of the present invention is to provide a piezoelectric device having a support structure that is electrically and mechanically stable even when vibrations or shocks are applied to the resonator.

A second object of the invention is to provide a piezoelectric device having a support structure with small changes in resonant frequency, anti-resonant frequency, resonant resistance, and anti-resonant resistance.

A third object of the present invention is to provide a piezoelectric device having a support structure that has good working efficiency, improves the rate of non-defective products, and reduces costs.

That is, the present invention is characterized in that in a piezoelectric device in which a conductive elastic material is placed between a terminal with a protrusion and a piezoelectric resonator plate, the contact protrusion area is made larger than in a case where the conductive elastic material is not placed. This is a piezoelectric device.

This invention, its objects and features will become more apparent from the following examples.

In the drawings, the same parts are denoted by the same numbers and the description thereof will be omitted. Reference numerals 8 and 9 are metal terminals, the protrusions 10 and 11 of which are characterized by a larger contact area A than the protrusions 4 and 5 of conventional metal terminals 2 and 3. Reference numerals 12 and 13 are conductive elastic sheets. , have approximately the same size as the piezoelectric resonator plate 1, and are located between the piezoelectric resonator plate 1 and the metal terminals 8 and 9, respectively. In the assembled state, the projections 10 and 11 mechanically hold the piezoelectric resonator plate 1 via the conductive elastic sheets 12 and 13, and also establish electrical connection. Conductive elastic sheets 12, 13
The material itself is commercially available, and is not limited to isotropic conductive elastic sheets, but may also be recently commercially available anisotropic conductive rubber sheets or pressure-sensitive anisotropic conductive rubber sheets. The shape of the sheet itself is square, circular,
It can be rectangular, hexagonal, octagonal, oval, or any other shape. The size is also arbitrary. Further, the sizes of the conductive elastic sheets provided on both sides of the piezoelectric resonator plate may be different. It may be provided only on one side and provided only on the other side, and the other side may have a conventional structure. Moreover, the present invention
It is not only applicable to a resonator device as shown in Fig. 2, but also a ladder-type filter using such a resonator, or a split electrode provided on one surface using area vibration or radial vibration mode. , it can be applied to so-called three-terminal piezoelectric filters (such as those disclosed in Japanese Unexamined Patent Publication No. 52-110547 and Utility Model Application Publication No. 52-122630-2) using a full-surface electrode on the other surface. Of course. Although various examples of applying the present invention to a ladder-type filter can be considered, typical examples are listed below. An elastic conductive sheet is placed between the protrusion input terminal, the output terminal, and the direct fissure resonator in contact therewith. A conductive elastic sheet is placed entirely between the parallel resonator and the protruding terminal in contact with the parallel resonator.
A conductive sheet is placed entirely between the series resonators and the parallel resonators and the terminals that contact them. etc. Resonant frequency, anti-resonant frequency, resonant resistance when changing the contact area A of the protrusions 10 and 11,
Changes in antiresonance resistance are shown in FIGS. 3, 4, 5, and 6. As is clear from these results, by applying a conductive elastic sheet, the support area of the protrusion can be widened, and even if the contact pressure is increased, the characteristics do not change much, so the impact resistance is improved. can be improved.

As is clear from the above embodiments, according to the present invention, in a piezoelectric device in which a conductive elastic material is located between a terminal with a protrusion and a piezoelectric resonator plate, when no conductive material is located. Since the contact protrusion area is made wider, the following effects are achieved.

It is electrically and mechanically stable even when vibrations or shocks are applied to the resonator. Furthermore, changes in the resonant frequency, anti-resonant frequency, resonant resistance, and anti-resonant resistance are small.

When a conventional ladder-type filter is constructed with the structure shown in Figure 1, the characteristics in the attenuation range around -90 to 110 dB are extremely unstable and do not change significantly even if there is a slight impact or drop. Ta. Furthermore, the characteristic curve (rebound portion) in the frequency ranges higher and lower than the frequency showing the maximum attenuation amount exhibited a severe unevenness. Furthermore, although it was not possible to obtain a pole of about -80 to 90 dB, when the present invention is applied to a filter with the same number of stages, the pole becomes around -120 dB, and there is no unevenness in the bent area. In that case, failures would have started occurring around the 20th cycle, but according to the present invention, at least
Stable characteristics have been obtained up to 100 cycles. In the event of a light shock or drop, the conventional structure would generate a lot of shock noise, which would cause defects, but these defects have been reduced to 0, and the level fluctuation within the passband has been reduced to 0.5~ I was able to suppress the change from 1.~1.0dB to 0~0.2dB with almost no change. Conventionally, the terminal protrusions with a narrow contact area are in direct contact with the resonator electrodes, so if the resonator is given a light shock, dropped, or subjected to vibration, the resonator electrodes will rub against the terminal protrusions, causing the electrodes to be scraped. There were cases where the characteristics became poor.
In addition, the resonator plate itself could break if subjected to a strong impact. However, according to the present invention, these defects are eliminated and the piezoelectric resonator plate can be made thinner, resulting in a smaller device. Therefore, according to the present invention, the rate of non-defective products increased by 30%, and costs were significantly reduced. Note that a structure in which elasticity and conductivity are provided between the electrode and the terminal plate is disclosed in Japanese Utility Model Application Publication No. 52-60278. This prior invention does not mention the contact area of the terminal protrusion. These prior ideas include forming the terminal itself from a conductive polymer composite, forming only the protrusion from a conductive polymer composite and adhering it to the metal terminal, or coating the terminal with a conductive polymer composite. Therefore, the structure is more complicated than the present invention, and it is difficult to put it into practical use. However, according to the present invention, it is only necessary to position the conductive elastic material between the terminal and the piezoelectric resonator plate, and there is no need to precisely align the protrusions with the node points of the piezoelectric resonator plate and bring them into contact, as in the conventional row of FIG. This facilitates automatic assembly of piezoelectric devices.

[Brief explanation of the drawing]

Fig. 1 is a side view of a conventional example, Fig. 2 is a side view of an embodiment of the present invention, Fig. 3 is a diagram showing the relationship between changes in terminal protrusion area and changes in resonant frequency, and Fig. 4 is a diagram showing the relationship between terminal protrusion area and change in resonance frequency. A diagram showing the relationship between changes in area and changes in anti-resonant frequency. Figure 5 is a diagram showing the relationship between changes in terminal protrusion area and changes in resonant resistance. Figure 6 is a diagram showing the relationship between changes in terminal protrusion area and anti-resonance resistance. FIG. 1... Piezoelectric resonator plate, 8, 9... Terminal, 10, 1
1... Protrusion.

Claims (1)

[Claims] 1. In a piezoelectric device in which a conductive elastic material is positioned between a terminal with a protrusion and a piezoelectric resonator plate,
A piezoelectric device characterized in that the contact protrusion area is larger than that in a case where a conductive elastic material is not placed.