JPS6335417Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a support for measuring the resonant frequency of a piezoelectric vibrator, and utilizes edge mode vibration in which vibration energy is concentrated at one longitudinal end of a thin rectangular piezoelectric ceramic plate. The present invention relates to a support for measuring the resonance frequency of a piezoelectric vibrator.

In the edge mode vibration of a rectangular piezoelectric ceramic plate, the vibration energy is concentrated at the tip where the drive electrode is provided, so the distance from the front end surface of the piezoelectric ceramic plate where the drive electrode is provided is approximately 1.5 of the width of the piezoelectric ceramic plate. Even if you fix the other end while leaving a part that is more than twice as large, it will not only have almost no effect on the vibration characteristics, but by fixing the rear end, spurious vibrations such as width vibration or length vibration can be suppressed. I can do it.

Therefore, in order to accurately measure the resonance characteristics of the edge mode resonator, it is desirable to actively fix the rear end.

FIG. 1 shows an example of the electrode configuration of a three-terminal ceramic filter constructed using edge mode vibration. As shown in FIG. Electrodes 2, 3 and 4 are provided, and each drive electrode 2,
3 and 4 are extended to the other end of the piezoelectric ceramic plate 1 to provide an input terminal 2', a ground terminal 3', and an output terminal 4' as connection terminals with external lead terminals.
Furthermore, as shown in FIG. 1b, two floating electrodes 5 and 5' are provided on the back surface of the piezoelectric ceramic plate 1 at positions corresponding to the drive electrodes 2, 3 and 3, 4, respectively.

Generally, the center frequency of a ceramic filter is determined by the resonant frequency of the piezoelectric vibrator used.
In order to set the center frequency of a ceramic filter within a certain range, it is necessary to set the resonant frequency within a certain range in advance. Furthermore, when cascading multiple ceramic filters to configure a multi-element ceramic filter,
Unless the center frequencies of each ceramic filter are matched with high accuracy, ripples may occur. As an example, 2 with a center frequency of 455KHz
For element type ceramic filters, the center frequencies of the two ceramic filters are each required to fall within the range of 455±1 KHz.

The resonant frequency of a piezoelectric vibrator is determined by the sound velocity, which is a material constant of the piezoelectric ceramic used, and the dimensions of the piezoelectric vibrator. It is inevitable that the resonance frequency will vary by about ±1%. Therefore, selection and adjustment of the resonant frequency is generally required.

The present invention aims to provide a support base for efficiently and stably measuring the resonant frequency of edge mode resonators by utilizing the characteristics of the edge mode resonators. Using an equal boat bottom type support for piezoelectric vibrator measurement, a raised pedestal for fixing the piezoelectric vibrator to be measured is provided at one end of the bottom, and the opposite end and both sides of the fixed pedestal are provided. It is characterized by having a slope on the inside so that the upper opening is wider than the bottom.

The present invention will be explained below with reference to the drawings. Figure 2 is a top view of the measurement support of the present invention;
The figure is a sectional view taken along line A-A' in FIG. Second
In the figure, the shape and dimensions of the bottom part 6 are almost the same as the shape and dimensions of the vibrator to be measured, and the shape and dimensions of the opening part 7 are similar to those of the vibrator to be measured.
The dimensions are larger than the shape and dimensions of the vibrator to be measured. Further, a pedestal 8 for supporting and fixing one end of the vibrator to be measured is provided at one end of the bottom.

A method for measuring the resonant frequency of an edge mode ceramic filter resonator using the measurement support of the present invention will be described with reference to FIGS. 4 and 5.

When the vibrator 1 to be measured is placed in the support base according to the present invention, the vibrator is stabilized at the position shown in FIG. 4, where the bottom of the support base is designed to have approximately the same shape and dimensions as the vibrator. Next, when the vibrator to be measured is fixed on the pedestal 8 using the holding plate 9, the vibrator is fixed as shown in FIG. Avoid contact. In this state, by bringing the measurement terminal 10 into contact with the external connection terminals 2', 3' or 3', 4' near the holding plate 9, the resonant frequency of the edge mode ceramic filter vibrator can be measured.

If you measure an edge mode vibrator using the support stand of the present invention, the position of the vibrator will automatically become constant just by placing the vibrator in the boat-bottom support stand, allowing you to always measure in a constant state. This eliminates most of the variation in measured values due to support. Furthermore, since the vibrator is easy to handle, the mechanism for constructing an automatic measuring device is simplified.

As described above, by using the measurement support of the present invention, it becomes possible to efficiently and stably measure the resonance frequency of an edge mode piezoelectric vibrator, and its practical effects are significant.

[Brief explanation of the drawing]

Figure 1 shows an example of the electrode configuration of a three-terminal ceramic filter constructed using edge mode vibration.
The figure is a top view of the measuring support according to the present invention, FIG. 3 is a sectional view of the measuring support according to the present invention, and FIG.
FIG. 5 is a state diagram when measuring an edge mode ceramic filter vibrator using the measuring support of the present invention. In the figure, 1...piezoelectric ceramic plate, 2,
3, 4... Drive electrode, 2', 3', 4'... External connection terminal, 5, 5'... Floating electrode, 6... Bottom,
7...Opening, 8...Pedestal, 9...Press plate, 10
...Measurement terminal.

Claims (1)

[Scope of utility model registration request] A boat bottom-shaped piezoelectric vibrator measurement support whose bottom dimension is approximately equal to the dimension of the piezoelectric vibrator to be measured is provided with a higher fixing pedestal at one end of the bottom portion for fixing the piezoelectric vibrator to be measured; A support stand for piezoelectric vibrator measurement, characterized in that the opposite end and both sides of the fixing stand are sloped so that the upper opening is wider than the bottom.