JPS60150310A - Piezoelectric vibrator - Google Patents

Abstract

PURPOSE:To obtain easily a high resonance frequency by providing plural adjacent regions different from the direction of polarization and providing an electrode in common to said regions. CONSTITUTION:The polarization direction in the regions 11A, 11B of a piezoelectric ceramic forming body 11 is made opposite as shown in arrows B and C respectively and electrodes 12, 13 are formed in common to the adjacent regions 11A, 11B. Since two-division or three-division structure is adopted in this way, the piezoelectric vibrator having a higher resonance frequency to the piezoelectric ceramic forming body of the same material and size is attained.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a piezoelectric vibrator.

BACKGROUND OF THE INVENTION Piezoelectric vibrators formed from piezoelectric ceramics such as Pb(Zr/MehaT i //, 2) Oa have come to be widely used as resonators and filters.

In such applications, a device having a resonant frequency suitable for the purpose is required. As an example of this German conventional piezoelectric vibrator, as shown in the schematic diagram 'I+i') in FIG. There is one in which the entire piezoelectric ceramic molded body 1 is polarized in the direction shown by arrow A, and electrodes 2 and 3 are applied to the rear and lower surfaces of the piezoelectric ceramic molded body 1 by a method such as vapor deposition.

In a piezoelectric vibrator with such a structure, the resonant frequency is usually determined by randomly selecting the vertical dimension, horizontal dimension, depth, and shape of the ceramic molded body 1. . However, when attempting to select a higher resonance frequency, for example around g00KH7, by using such longitudinal stretching vibration and spreading vibration, the shape of the piezoelectric ceramic molded body for this purpose becomes too small. Therefore, the frequency adjustment method and the method of supporting the piezoelectric element become extremely difficult. Also, when the shape becomes smaller and the difference between the thickness and the vertical and horizontal dimensions becomes smaller,
There was a problem in that parasitic vibrations increased and it became difficult to obtain a clean waveform.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a piezoelectric vibrator that eliminates the apex of the prior art as described above and allows easy control of a crystalline resonant frequency.

Structure of the Invention The piezoelectric vibrator according to the present invention is characterized in that it has at least a adjacent regions with different polarization directions, and that a common electrode is provided for one of the adjacent regions.

Embodiments Next, the present invention will be described in more detail with reference to embodiments of the present invention based on FIGS. 2 to 9 of the accompanying drawings.

Figure Ω is a schematic perspective view showing a piezoelectric element as an example of the present invention. The piezoelectric vibrator of this example is Pb
(Zr//, 2. Ti///, 2) Electrons 1m 12 and 13 are applied to the top and bottom surfaces of the piezoelectric ceramic molded body 11 such as Os.
In this respect, the 1st I:/I
It is exactly the same as the conventional example (2R) explained in connection with the above. However, according to the present invention, the pressure
In the figure, the left half area 11A and the right half area 11B
The polarization directions are opposite to each other as shown by arrows B and C, respectively. Therefore, the electrodes 12 and 13 are
This is common to the adjacent regions 11A and 11B.

An example of a method for manufacturing such a piezoelectric vibrator is described in Part 3.
This will be briefly explained with reference to the drawings. Piezoelectric ceramic molded body 1
Before forming the electrodes 12 and 13 on the L side and bottom surface of 1, the third
As shown in the schematic cross-sectional view of the figure, polarization electrodes 14 and 15 and polarization electrodes 16 and 17 are formed on the L surface and lower surface of each of regions 11A and 11B. Then, by applying voltages in opposite directions between the polarization electrodes 14 and 15 and between the polarization electrodes 14 and 11, the region 11
Polarization is performed by applying electric fields in opposite directions to A and 11B. After performing such polarization, the polarization electrodes 14, 1
5. Remove all 16 and 17 and create areas 11A and 1
The electrodes 12 and 13 common to 1B may be applied by a method such as vaporization a).

FIG. 7 is a schematic perspective view showing a piezoelectric vibrator as another embodiment of the present invention. The piezoelectric vibrator of this example is Pb
(Zr//, 2.71//, 2) Electrodes 22 and 23 are provided on the L surface and lower surface of the piezoelectric ceramic molded body 21 such as Os.
In this respect, it is exactly the same as the conventional example explained with reference to FIG. However, according to the present invention, the pressed ceramic molded body 21 has arrow marks in the left third area 21A, the center third area 21B, and the right third area 21G in the figure.
As shown by E and F, the polarization directions are mutually opposite between adjacent ones. And the electrodes 22 and 23 are connected to the phase 1
! i'i 1 is common to the areas 21A, 21B, and 21G. Such a piezoelectric vibrator can be manufactured according to the manufacturing method ff described with reference to FIG.

As mentioned above, according to the present invention, the resonant frequency of the piezoelectric vibrator changes by creating the co-divided area structure as shown in Figure Ω and the three-divided area structure as shown in Figure 3. lir: The results of experiments to confirm this are shown in Figures S, 6 and 7.

First, the graph in FIG. S shows the conventional structure shown in FIG.
: i 70 +1m, thickness 0 S 1.11+] 1 Like, common 4
9 frequency, approximately 300KHz.

Next, the graph in FIG. 4 shows the resonant frequency when the piezoelectric ceramic molded body 11 having the structure according to the present invention shown in 11m no. This 'W k has a resonant frequency of about 330, as shown by the reference mark +3 days.
It was rare at KHz.

Furthermore, graph 1 in Figure 7, misfire 1 shown in Figure 7,! I
This figure shows the results of examining the resonance frequency when a piezoelectric ceramic molded body 21 of +14 construction according to J is made of exactly the same material and the same dimensions as the piezoelectric ceramic molded body 1; , the resonant frequency is about 300KH
Beta with z.

As described above, by adopting the λ division and three-division structure as in the present invention, it is possible to obtain a piezoelectric vibrator having a higher resonant frequency with the same material and size, pressure '+Jf, and ceramic molded body.

1j; 1. In the above-mentioned embodiment, the structure is divided into two and three parts, but according to the present invention, even if the number of divisions is arbitrary, it is possible to create a pressure oscillator with a better resonant frequency. I can do it. As described above, according to the present invention, piezoelectric vibrators having different resonance frequencies can be obtained by appropriately varying the polarization direction of each region of the piezoelectric ceramic molded body. This is thought to be because the fundamental mode of the piezoelectric vibrator is suppressed when the regions are polarized in the same direction, and only higher-order vibration modes can be used.

Further, in the above-mentioned embodiments, a rectangular piezoelectric vibrator was explained, but the present invention can be similarly applied to a disk-shaped piezoelectric vibrator. As shown in the cross-sectional view of FIG. 7, the center region 31A of the disk-shaped pressurized ceramic molded body 31 is polarized in the direction of the arrow J, and the outer peripheral region 31B is polarized in the direction of the arrow, so that the central region 31A and the outer peripheral region 31B are polarized. By providing a structure in which common electrodes 32 and 33 are provided, a higher resonant frequency can be achieved.

Effects of the Invention As mentioned above, the piezoelectric vibrator of the present invention can have a higher resonance frequency without making the piezoelectric ceramic jA shape particularly small, so it is possible to improve the frequency adjustment method and the element support method @+6. There will be no problems such as L-shape, and there will be no problem of increased raw vibrations due to distortion.

[Brief explanation of drawings]

Figure 1 is a schematic perspective view showing an example of a conventional piezoelectric vibrator.
FIG. 2 is a schematic perspective view showing a piezoelectric vibrator according to an embodiment of the present invention, FIG. 3 is a schematic diagram for explaining an example of a method for manufacturing the piezoelectric vibrator shown in FIG. 1, and FIG. A schematic perspective view showing a piezoelectric vibrator according to another embodiment of the invention, and FIGS. FIG. 5 is a schematic perspective view showing a piezoelectric vibrator according to another embodiment of the present invention, and FIG. 7 is a schematic cross-sectional view of a piezoelectric vibrator of 0!g diagram. .21.31... Pressed ceramic molded body,
11A, 11B, 21A, 21B, 21G, 31A, 3
1B... Area, 12, 13.22.23.32.33... Electrode Figure 1 Figure 4 Figure 6 KHz) -→ Fig. S Fig. 9

Claims (1)

[Scope of Claims] (c) A piezoelectric vibrator characterized by having at least Ω adjacent regions having different directions of polarization, and a common electrode provided for the adjacent regions. 0) The direction of the polarization is , the piezoelectric vibrator according to claim 1, wherein the directions are 2fl perpendicular to the electrodes, and the directions are opposite to each other between the adjacent regions.