JPS61195000A - Manufacture of composite piezoelectric body - Google Patents

Abstract

PURPOSE:To easily form composite piezoelectric body by cutting across laminate surface of more than one piezoelectric ceramic layers with polymeric layers in between, providing terminals for cut laminates, and performing polarization of piezoelectric ceramic material of cut laminates taking advantage of the formed terminals. CONSTITUTION:More than one piezoelectric material 10 with a specified thickness are laminated with a polymeric material, an adhesive 11 for example, between the layers. The laminate is then cut in the direction across the layer surface into thin slices. Next, terminals 12a and 12b are formed for cut slices. Thereafter, a high voltage is applied across the terminals 12a and 12b to completely polarize piezoelectric material 10. As a result, the electromechanical coupling factor of the ceramic is retained, and a composite piezoelectric body with an effective acoustic impedance which depends on the ration of the ceramic to the adhesive as a polymeric material is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a composite piezoelectric body formed by combining a piezoelectric ceramic and a polymer material.

[Technical background of the invention and its problems] In medical ultrasound diagnostic equipment, piezoelectric ceramics are used as a means for transmitting ultrasound into a living body and receiving reflected components of the transmitted ultrasound from the living body. Piezoelectric vibrators are widely used.

By the way, the acoustic impedance of piezoelectric ceramic is about 3
While it is 0x10Bkg/n+2 .S, that of a living body is approximately 1.5x106 kmMm2 .S, which is significantly different. , Therefore, the pressure It? It is common to laminate a matching member on the surface of the lamic for matching the impedance of the living body.

In response, attempts have been made to reduce the acoustic impedance of the piezoelectric vibrator itself and match it with the living body by configuring a piezoelectric vibrator by combining a piezoelectric ceramic and a polymer material.

A method for manufacturing such a composite piezoelectric body is, for example, a method in which ceramic fibers are solidified with a polymeric material, thinned into thin pieces, and then polarized (Mat.

Res, Bull, vol, 15. P. 13
71 (1985)), or a method in which a piezoelectric ceramic subjected to ordinary polarization is finely cut vertically and horizontally and the cut grooves are filled with a polymeric material (43rd Nichicho Medical Lecture Proceedings P, 503 (Showa 1958)) are known.

However, it is technically difficult to turn ceramic into fibers, and cutting piezoelectric ceramic into small pieces vertically and horizontally takes time and ends up being expensive.

[Objective of the Invention 1 The present invention has been made in view of the above circumstances, and its object is to provide a method for easily and inexpensively manufacturing a composite piezoelectric body.

[Summary of the Invention] The outline of the present invention for achieving the above object is as follows: a first step of laminating a plurality of piezoelectric ceramic materials formed to a predetermined thickness via a polymeric material; A second step of cutting the laminated product in the step in the direction intersecting the laminated surface, a third step of forming an electrode on the product cut in the second step, and a third step of forming an electrode on the product cut in the second step. The piezoelectric ceramic material is polarized through the formed electrodes.
By including the fourth step, the composite J[l can be manufactured easily and at low cost.

[Embodiments of the invention] Hereinafter, the present invention will be specifically explained with reference to Examples.

1 to 3 are perspective views for explaining a manufacturing method according to an embodiment of the present invention.

First, as shown in FIG. 1, a plurality of piezoelectric ceramic materials 10 formed to a predetermined thickness are laminated via a polymeric material such as an adhesive 11 (first step).

Here, the piezoelectric ceramic material 10 is fired in advance and formed into a thin plate shape, and has not yet been subjected to polarization treatment.

Further, the adhesive 11 can be epoxy-based or rubber-based. In order to keep the thickness of the adhesive 11 constant, it is preferable to use a suitable spacer or apply the adhesive 11 by a screen transfer method.

Next, the material laminated in the first step is cut into thin plates in a direction intersecting the laminated surface (second step).
. The cut piece is shown in Figure 2.

Next, as shown in FIG. 3, electrodes 12a and 12b are formed on the parts cut in the second step (third step).

The electrodes 12a and 12b can be formed by a vapor deposition method, a coating method, or the like.

Then, the piezoelectric ceramic material 10 is polarized by applying a high voltage through the formed electrodes 12a and 12b (fourth step).

This maintains the electromechanical coupling coefficient of the ceramic, since the ceramic itself is completely polarized, and provides a composite piezoelectric body with an effective acoustic impedance determined by the ratio of the ceramic to the polymer adhesive.

In this example, a plurality of piezoelectric ceramic materials are laminated with an adhesive, the laminated material is cut in a direction intersecting the laminated surface, and electrodes are formed on the cut material. , a composite piezoelectric material is produced by polarization treatment through formed electrodes, and ceramics are produced as in the conventional method.

Since the method does not involve cutting the piezoelectric ceramics or tubes into thin strips in the vertical and horizontal directions and filling the cut grooves with a polymeric material, the composite piezoelectric material can be manufactured easily and at low cost.

Next, a case where the composite piezoelectric body manufactured according to the above embodiment is formed into an array type and applied to an electronic scanning ultrasonic probe will be described with reference to FIG. 4.

FIG. 4 is a perspective view showing the configuration of an electronic scanning type ultrasound probe.

14 in the same figure is a backing material, and this para-kink material 14
A composite piezoelectric body 13 (see FIG. 3) is bonded thereon via one end of the flexible electrode plate 15.

The joined composite piezoelectric body 13 is connected to the flexible electrode plate 15
The cut grooves formed by the cutting are filled with a polymeric material such as an adhesive 16. The unfilled adhesive 16 forms a matrix with the previously filled adhesive 11. As a result, the ceramics of the composite piezoelectric body 13 are formed into columnar shapes as shown by 10a, and are arranged in an array.

Note that 17 is a ground electrode connected to the electrode 12a.

Since the electronic scanning ultrasonic probe having the above configuration includes a composite piezoelectric material, it can be easily matched with a living body and can be provided at a low cost.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a method for easily and inexpensively manufacturing a composite piezoelectric body.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams for explaining a manufacturing method according to an embodiment of the present invention, and FIG. 4 is an electronic scanning ultrasonic probe having a composite piezoelectric material manufactured according to this embodiment. FIG. 10...Piezoelectric ceramic material, 11...
・Polymer material, 12a, 12b... Electrode, 1
3...Composite piezoelectric material. Funeral diagram 2

Claims (2)

[Claims] (1) In manufacturing a composite piezoelectric body capable of transmitting and receiving ultrasonic waves, a first step of laminating a plurality of piezoelectric ceramic materials formed to a predetermined thickness via a polymeric material;
a second step of cutting the layered product in the first step in a direction crossing the laminated surface; a third step of forming electrodes on the layer cut in the second step; A method for manufacturing a composite piezoelectric body, comprising a fourth step of polarizing the piezoelectric ceramic material through the electrode formed in the step. (2) The method for manufacturing a composite piezoelectric body according to claim 1, wherein the polymer material is an adhesive.