JPH0478033B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a piezoelectric element, and in particular to a method for manufacturing a piezoelectric element, in which a large number of surface electrodes are formed on a large unpolarized piezoelectric ceramic plate, the plate is polarized all at once, and then the piezoelectric elements are cut and separated into individual piezoelectric elements. , relates to a method for simultaneously manufacturing a large number of piezoelectric elements.

Conventionally, in order to simultaneously obtain a large number of piezoelectric elements from a large piezoelectric ceramic plate as described above, the following process has been adopted as shown in FIG.

(1) Prepare a large unpolarized piezoelectric ceramic plate 1 (Fig. 1A), and attach it to the piezoelectric element plate 1 with predetermined dimensions and shape.
1, 12..., 21, 22..., 31, 32...
..., 41, 42... (Fig. 1B).

(2) Both electrodes P are formed on both sides of each cut and separated piezoelectric element plate (representatively represented by reference numeral 11) by an appropriate method such as sputtering or vapor deposition (see Fig. 1C). ).

(3) Each piezoelectric element plate is polarized by connecting the above-mentioned surface electrode P to both poles of a high voltage source E for voltage division to form a piezoelectric element (FIG. 1D).

As described above, in the conventional manufacturing method, electrode formation and polarization were performed after cutting and separating the large unpolarized piezoelectric ceramic plate 1 into small-sized piezoelectric element plates. It is difficult to homogenize the electrical characteristics of the material, and it is inconvenient and time-consuming to handle, which has the disadvantage of not increasing production efficiency and increasing manufacturing costs.

One possible way to improve this shortcoming is to form electrodes and polarize the large plate as it is. When attempting to form individual particles and perform polarization, there are the following difficulties.

(1) It is difficult to uniformly connect (bring in contact with) all the electrodes to a high-voltage power source for polarization, resulting in variations in contact resistance.

(2) For this reason, variations occur in the polarization voltage actually applied to each piezoelectric element, and variations also occur in the strength of polarization itself.

(3) If the difference in polarization voltage between adjacent piezoelectric elements becomes larger than a certain level, leakage may occur between the piezoelectric elements and damage the high voltage power supply for polarization.

The present invention provides a novel method for manufacturing a piezoelectric element that overcomes the above-mentioned drawbacks and difficulties.

Below, one example of the manufacturing method of the present invention will be described.
This will be explained with reference to the figures. The manufacturing method of the present invention consists of the following steps. In addition, in Figure 2, the first
The same reference numerals as in the figures represent the same or equivalent parts.

(1) Prepare a large unpolarized piezoelectric ceramic plate 1 (A in Fig. 2), and apply piezoelectric element surface electrodes P11, P12..., P21, P22... to at least one surface thereof.
. . , P31, P32 . . . are formed in a matrix, and thin wire-like electrodes Q for interconnecting these surface electrodes are formed (B in FIG. 2).

As is well known, the pattern of the electrodes on the other side (not shown) may be in the same matrix shape as shown, or electrodes may be formed extending over the entire surface. .

(2) Connect at least one electrode on each side of the large unpolarized piezoelectric ceramic plate 1 to a polarization high-voltage power source E, and apply a high voltage to the large piezoelectric ceramic plate 1 to polarize it all at once. (C in Figure 2).

(3) Cut and separate the piezoelectric ceramic plate along the dotted line shown in FIG. 2D so as to include each individual surface electrode. In this case, the cutting line is the thin wire electrode Q.
pass through the intersection of

(4) Through the above steps 1 to 3, a large number of piezoelectric elements 11, 12..., 21, 22... each having predetermined electrodes formed on both sides of a piezoelectric ceramic plate can be obtained at the same time (see Fig. 2). E).

In the manufacturing method of the present invention described above, as described above, thin wire electrodes are formed to interconnect individual surface electrodes provided in a matrix, and all surface electrodes are electrically connected. Therefore, when applying a high voltage for polarization, there is no possibility that variations in contact resistance occur for each electrode on each surface. Therefore,
There is no risk of variations in polarization voltage applied to individual piezoelectric elements or leakage between adjacent electrodes.

Therefore, according to the present invention, the electrical characteristics of the piezoelectric element can be made homogeneous and the process can be simplified, and the number of steps required for polarization can be significantly reduced.
Overall, manufacturing costs can be reduced and manufacturing efficiency can be improved.

Furthermore, as shown in FIG. 2E, in each piezoelectric element after being cut and separated, a part of the thin wire electrode Q remains in addition to the surface electrode P for actuation. The results of an experiment in which a piezoelectric element obtained using the manufacturing method was incorporated into a Ragout type ceramic filter of a well-known radio intermediate frequency (455 KHz) amplifier circuit showed that such residual thin wire electrodes did not have any effect on its operation. It was confirmed that there was no occurrence of spurious signals (for example, no spurious emissions were generated).

Among the piezoelectric elements manufactured by the method illustrated and explained above, for example, one thin wire electrode remains in the piezoelectric elements indicated by numerals 11, 14, etc. in FIG. Two thin wire electrodes will remain in the case where the electrode is removed.

For this reason, when precision is particularly required, it becomes necessary to distinguish between one remaining thin wire electrode and two remaining thin wire electrodes, and as shown in Figure 2E, cut and separate the piezoelectric elements into individual piezoelectric elements. This poses a problem in that these items must be identified and separated and stored separately.

FIG. 3 shows an example of a thin line electrode pattern to solve the above-mentioned problem.
In the figure, the same reference numerals as in FIG. 2 represent the same or equivalent parts. Surface electrode P1 for each piezoelectric element
1, P12..., P21, P22..., etc. are the second
As in the case shown in the figure, they are arranged in a matrix.

As is clear from the figure, the first thin wire electrode Q1
In this case, four adjacent surface electrodes in two rows and two columns, such as a set of P11, P12, P21, and P22, or a set of P13, P14, P23, and P24, are connected in a cross-over manner.

Further, the second thin wire electrode Q2 is located at the intersection R11, R1 of the cross-shaped first thin wire electrode Q1.
2, R21, and R22 are electrically connected. Furthermore, this second thin wire electrode Q2
are formed to coincide with the cutting lines (dotted lines in FIG. 3) when the piezoelectric ceramic plate 1 is cut and separated into individual piezoelectric elements after polarization.

If the thin wire electrode Q2 is configured as described above, the thin wire electrode Q2 disappears when the piezoelectric ceramic plate 1 is cut and separated after being collectively polarized. the result,
All piezoelectric elements will have exactly the same electrode pattern as shown in FIG. 4, ie, in addition to the required surface electrodes, only one residual thin wire electrode.

Therefore, if the thin wire electrodes Q1 and Q2 are formed into an electrode pattern as shown in FIG. 3, all of the problems described above with respect to the embodiment shown in FIG. 2 can be solved.

[Brief explanation of drawings]

Fig. 1 is a process diagram showing a conventional piezoelectric element manufacturing method, Fig. 2 is a process diagram of an embodiment of the present invention, and Fig. 3 is another example of an electrode pattern on a piezoelectric ceramic plate according to the present invention. The plan view, FIG. 4, is a plan view of one piezoelectric element cut and separated from FIG. 3. 1...Unpolarized piezoelectric ceramic plate, 11, 12, 21,
22...Piezoelectric element, P11, P12, P22...
Surface electrodes for piezoelectric elements, Q1, Q2...thin wire electrodes.

Claims (1)

[Scope of Claims] 1. A large number of surface electrodes having a predetermined shape and thin wire electrodes connecting the surface electrodes are formed at a predetermined position on at least one surface of an unpolarized piezoelectric ceramic plate, and A method of manufacturing a piezoelectric element, which comprises polarizing the piezoelectric ceramic plate by connecting at least one location to one pole of a high-voltage power source for polarization, and then cutting and separating the piezoelectric ceramic plate into electrodes on each surface. 2. The plurality of surface electrodes are arranged in a matrix, and a set of four surface electrodes arranged in two rows and two columns adjacent to each other is formed, and two surface electrodes are arranged in each set, and the first thin wire electrodes are arranged in a matrix. Claim 1, characterized in that they are connected to each other in a cross-crossing manner, and the intersection points of each set of cross-crossing fine wire electrodes are electrically connected to each other by a second thin wire electrode for communication. A method for manufacturing a piezoelectric element. 3. The method of manufacturing a piezoelectric element according to claim 2, wherein the thin wire electrode for communication is formed to correspond to a portion of the piezoelectric ceramic plate to be cut.