JPS5943619A - Piezoelectric ceramic element - Google Patents

Abstract

PURPOSE:To obtain very simply a piezoelectric ceramic element having various characteristics, by designating an angle formed between a polarized axis of the polarized piezoelectric ceramic and an opposite direction of a pair of counter electrodes as a prescribed angle. CONSTITUTION:First, the polarized piezoelectric ceramic block 14 is prepared. The polarized axis of the piezoelectric ceramic block 14 is in the direction as expressed by the arrow A. Further, electrodes 15, 16 are electrodes formed for polarization processing. Then, the piezoelectric ceramic block 14 is sliced along a direction C having (90 deg.-theta) angle to the polarized axis A, that is, cut off. Further, the counter electrodes 12, 13 are formed on a pair of opposite surfaces in the slicing direction C of the piezoelectric ceramic 11 obtained through slicing, that is, on a pair of opposite surfaces of the piezoelectric ceramic 11 by an electrode forming method. Thus, the piezoelectric ceramic element 10 having various piezoelectric characteristics is obtained.

Description

[Detailed Description of the Invention] Ini's invention 4J is based on DE electroceramics element, Hj
The present invention relates to a piezoelectric ceramic vibrator having a polarization axis in the direction of the polarization axis.

Conventional piezoelectric/lamix element J-1''(' is a perspective view in Fig. 1).
゜) Vibrating t-do (thickness longitudinal J1 rib) parallel to
As shown in the perspective view 7, the swing is perpendicular to the convenient direction.
-Only the thickness overlapping vibration has been used/2. However, depending on the composition of the material constituting the piezoelectric ceramic (4f is L), these vibration modes may not be available. For example, the so-called 17-piece series, or Pb (
Zr, Ti) In the 09-based piezoelectric ceramic element, p
Due to the Poisson's ratio relationship between the composition on the b -T' i Os side and the composition on the p bzr Os side, it has been impossible to achieve energy confinement by thickness longitudinal vibration using the usual method. Similarly, in lead titanate ceramics, it is possible to confine the fundamental wave of thickness longitudinal vibration, but it is impossible to confine the fundamental wave of thickness longitudinal vibration. As a result, in conventional piezoelectric ceramics, piezoelectric constants such as permittivity, electromechanical coupling coefficient, and mechanical quality factor vary depending on the vibration mode and composition used. It was severely restricted.

Furthermore, regarding the frequency-temperature characteristics of conventional piezoelectric helical elements, the composition of the material constituting the element and the vibration used
-C was uniquely defined by the code. Therefore, in order to create a piezoelectric ceramic element with arbitrary frequency-temperature characteristics, it is necessary to prototype and experiment with elements with countless types of compositions, which has never been possible.

Therefore, the main object of the present invention is to provide a piezoelectric ceramic element having various piezoelectric constants that cannot be obtained with conventional piezoelectric ceramic elements.

Another purpose of this kidney light is that the frequency temperature characteristics are improved.
An object of the present invention is to provide an electroceramic element.

This invention is summarized as follows:1.
Electroceramics are formed by sandwiching this piezoelectric ceramics.
J3 is a piezoelectric ceramic element having a pair of opposing electrodes, and is characterized in that the angle θ between the polarization axis of the piezoelectric ceramic and the opposing direction of the pair of electrodes is 06×θ×900. , a piezoelectric ceramic element.

FIG. 3 is a schematic side view for explaining the invention more specifically. Referring to FIG. 3, the piezoelectric ceramic element 10 of the present invention includes a polarized piezoelectric ceramic 11 and a 1
A pair of opposing electrodes 12 and 13 are provided, and a portion 14 of the piezoelectric ceramic 11; axis (direction shown by arrow Δ in FIG. 3)
The angle θ between the opposing electrodes 12 and 13 of 1 zu 1 (the direction shown by the arrow in FIG. 3) is Oo<D<9
It was set to 00-(there.

The procedure for producing the piezoelectric ceramic element 10 of the present invention having such a configuration will be explained with reference to FIG. first,
A polarized piezoelectric ceramic block 14 is prepared. The polarization axis of this piezoelectric ceramic block 14 is indicated by the arrow Δ
It is in the direction shown. In addition, 15.16 is the electrode that was formed (2 and 4t) for the TFI process.Next, the piezoelectric ceramic block 1' was moved in the direction C that made an angle of 90°-θ (slice angle to be described later) with the polarization axis △. Slice along”?J
Nawachi cut it off.

Then, as shown in FIG. 5, counter electrodes 12. are formed on the surfaces of the piezoelectric ceramic 11 obtained by slicing in the slicing direction C, that is, on the pair of opposing surfaces 1-1- of the piezoelectric ceramic 11, by a known electrode forming method. By forming 13, the piezoelectric ceramic element 1o can be obtained.

Therefore, it can be said that the angle θ formed by the polarization axis of the piezoelectric ceramic 11 and the opposing method of the opposing electrodes 12, 1ζ3 has a correlation with the slice angle (90' to θ) at which the piezoelectric ceramic 11 is cut out.

11. Used in this invention. As II electric ceramics,
Pi) (Zr, Ti)03 series ceramics,
All piezoelectric ceramics that can be polarized, such as BL-IO and ceramics, can be used.

Friend Tsudan” - P b Z I' o, s2 - T' io/Jg
Os 10 Powder with a composition of -5% by weight of Cr2O3 was prepared, mixed in a wet mixing mill for 20 hours, and dehydrated at 850°.
Calcination was carried out by holding in O for 2 hours. Next, after adding a binder and crushing it into M grains, 35 mm x 35 mm x
It was molded into a block with a size of 12 mm. The thus-formed block was held at 1250°C for 2 hours and fired to produce a ceramic block with a temperature of 30°C.
It had a size of mmx 3 Qv++x 1Qmm. 800 on both sides of the fired ceramic cock.
Form a silver electrode for 'CT' polarization treatment, and then
Polarization was performed by applying a DC voltage of KV, -'mm and holding it for 1 hour.Next, the ramic block was sliced in one direction at an angle of 90'-0 to the polarization axis direction. J3, J angle θ between the polarization axis and the counter electrode is 36.30o, 45', 60'' J:i
Five types of angles, cJ: and 85°, were set, and the sample corresponding to the angle θ of the groove U41 was blue. A counter electrode with a diameter of 1 to 2n+n+ was formed on each of these samples by vacuum evaporation.

For each trial [1] prepared as described above, the attenuation was investigated for its one-frequency stability, and the results are shown in Table 1.

Table 1 O: Usable △, response right direction It is understood that it is possible to utilize the Libery vibration 1 m-1 ~ (the S mode) when the angle is 30 degrees or more. 4-3, the "response right" state shown by τΔ in Table 1 indicates that the vibration IJ detector 1) is strong, but the vibration is not strong enough to use 1q. Figure 6 shows the amount of food loss vs. frequency characteristic when θ-60° (slice angle 305〉), and Figure 7 shows the attenuation maximum frequency characteristic when θ-30° (slice angle 60°). Shown in

Next, for the sample at each angle θ, the dielectric loss l'anδ,
The dielectric constant ε, the electromechanical coupling coefficient, and the mechanical quantity l'! Coefficient Q
m, frequency constant fc, resonant frequency temperature coefficient Cfr, and anti-resonant frequency temperature coefficient Cfa were measured. Apply this result to the second
Shown in the table.

Table 2 Angle θ (slice angle 90° - θ) and piezoelectric properties (thickness longitudinal/
Shear vibration 1 [: Piezoelectric constant of thickness longitudinal vibration mode with opposing Fri poles of 1 mm diameter 1 <, 5 bows 〃7) Piezoelectric constant of thickness shear vibration mode 1-anδ; Dielectric loss,
ε: dielectric constant, 1 (: electromechanical coupling coefficient Qm; friendly quality factor, fc; frequency constant Crr; resonant frequency temperature coefficient, Cra; anti-resonant frequency temperature coefficient, as is clear from Table 2, this example It will be understood that piezoelectric ceramic elements with various piezoelectric characteristics can be realized without changing the composition by appropriately changing the angle θ (slice angle 90° − θ). Unlike conventional piezoelectric ceramic elements, it is no longer necessary to subtly change the composition in multiple stages and conduct prototype production and experiments.

Further, the resonant frequency temperature coefficient C[1'' and the anti-resonant frequency temperature coefficient Cfa shown in Table 2 are shown graphically in FIG. 8 with the angle θ as the horizontal axis. As is clear from Figure 8,
It will be appreciated that the resonant frequency temperature coefficient Cfr and the anti-resonant frequency temperature coefficient (Ja) change by changing the angle θ.

Therefore, a piezoelectric ceramic element having a desired resonant frequency temperature coefficient Cfr can be obtained very easily.

Figure 9 shows the frequency temperature change in the thickness J-shear vibration mode when the angle is 60', and Figure 1 shows the frequency temperature change in the thickness shear vibration mode when the angle is 087°.
As is clear from Figure 0, by changing the angle θ,
It will be appreciated that the frequency temperature change may also be chosen arbitrarily.

Example 2 - In the same process as in Example 1 described in Y, the angle θ is 3°, 3
Five types of Tsukiden ceramic elements of 0°, 45°, 60°, J, and 85° were prepared as follows: P b , 7y l-a o;
o T' i 03+o, 5% by weight Ml102. When the piezoelectric ceramic element made of this J: sea urchin was examined for its reduced table suspension frequency characteristics, the J results shown in Table 3 were obtained.

As is clear from Table 3, the angle ranges from 03° to 45°.
Conventionally, it would be possible to beat the ``)-■- type ceramics by vertically vibrating the thickness and making use of the same force.

Example 3 In the same manner as in Example 1, 1] 71 series ceramics 1 straw Pb ZrxTi+-'X Os +0.51fa%
Using Cr2O, piezoelectric ceramic elements were fabricated at +1° C. with different compositions and angles θ, and their vibration-frequency characteristics were measured. The results are shown in Table 4.

1 thickness vertical □ layer 11 4th
As is clear from the table, by setting the angle θ to (30'), the composition changes to Pb Zr O, side or 1N) 1-i
It will be understood that the thickness longitudinal vibration mode can be utilized in any case on the 03 side. For example, in a composition where It will be understood that in the range of 30° to -87°, the thickness shear vibration limit is always utilized even if the composition changes.

As described above, according to the present invention, since the angle O between the polarization axis of the polarized piezoelectric ceramic and the opposing sides of the pair of opposing electrodes is 0°</7<9Q', It is now possible to extremely easily obtain piezoelectric ceramic elements having various characteristics such as U4+W, 4I:, and 1-, which conventional piezoelectric ceramic elements never had. Also, [)Z bobbin thread or P
It is now possible to utilize a confined vibration top, which has not been available in the past, with l-based piezoelectric ceramics, and the range of use of piezoelectric ceramic elements can be expanded further. Roughly, by appropriately setting the angle θ, the 11-electroceramic element J''-'E (
”=i and b become possible.

[Brief explanation of the drawing]

FIG. 1 is an il perspective view showing a conventional piezoelectric ceramic element. FIG. 2 is a perspective view of the same conventional piezoelectric lamic cord. Figure 33 shows 1. It is a schematic side view for explaining the J3E electroceramics element of the second invention. Fig. 4) From the piezoelectric p-laminate block 11 of this invention)
A schematic side view showing a state in which an electric lamic mulberry tree is cut out is shown. Figure 5 shows piezoelectric ceramics cut out from a piezoelectric ceramic block? A schematic side view of the piezoelectric ceramic element formed by forming a 1ftfi is shown. Figure 6 shows
Figure 7 is a graph showing the vibration-frequency characteristics when the angle θ is 30 degrees. Figure 8 is a graph showing the vibration-frequency characteristics when the angle θ is 30 degrees. Figure 9 is a graph showing the relationship between the chair angle and the frequency temperature coefficient. Figure 9 is a graph showing the frequency temperature change in the thickness vibration L-mode when the angle is 60°. Figure 10 is angle 87
In the figure, J3 shows the piezoelectric ceramic element, 11 is the piezoelectric ceramic element, and 11 is the piezoelectric ceramic element.
Ceramics, 12.13 is a pair of opposing electrodes, θ is minute w
The angle between the i-axis and the opposing direction of T1 (6 is not shown.
and 2 others) -17- 89 T j6 ←) "] 1 ・ 1 person 1 -L La number (MHz) 珀8 figure

Claims (1)

[Claims] 5) A piezoelectric ceramic Kyoko comprising a polar-treated piezoelectric ceramic and a pair of opposing electrodes formed by sandwiching the piezoelectric ceramic, is connected to the polarization axis of the ceramic, and the polarization axis of the ceramic is A piezoelectric lamics element, characterized in that the angle θ between the opposing directions of the electrodes satisfies 0'<o<9Q°C.