JPS62219896A - Method for working curved surface of ultrasonic vibrator - Google Patents

Abstract

PURPOSE:To simply obtain curved surface ultrasonic vibrators having small variance of the thickness of curved surface piezoelectric bodies and small variance of the thickness of electrodes at high reproducibility by holding a flat plate ultrasonic vibrator between a concave surface block and a convex surface block, deforming the flat plate ultrasonic vibrator by heating and forming a curved surface ultrasonic vibrator. CONSTITUTION:If a flat plate ultrasonic vibrator made by providing electrodes on both sides of a flat plate piezoelectric body 3b cut at high thickness accuracy is held between a concave surface block 5 and a convex surface block having a radius of curvature R and heated, plastic distortion is formed just before brittle fracture due to load stress. Distortion starts at three places, that is near the contact line with the convex R surface block 7 and two places near the contact line with concave R surface block, and speed of distortion near the contact line with the convex R surface block 7 is more than double compared with other two places as the load differs by twice. Accordingly, the center portion of flat plate ultrasonic vibrator starts distortion faster than other parts. With generation of distortion, load applied per unit area becomes smaller and speed of distortion decreases. After lapse of a certain time, the flat plate ultrasonic vibrator is deformed to a curved face vibrator having a radius of curvature R.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a curved surface processing method for providing a curved surface in the thickness direction of an ultrasonic transducer.

[Conventional technology]

Traditionally, the ceramics that form ultrasonic transducers are processed by cutting using a 9-turn diamond grindstone.

Cutting processing and those using laser light, ultrasonic processing using abrasive grains, lapping, and polishing.

Or, very rarely, it is performed by electric field discharge machining. As a processing method for obtaining a curved surface on a ceramic surface, a cutting method has been used in which a deformed diamond grindstone is rotated and moved in the longitudinal direction of the ceramic. As shown in Figure @3, the irregularly shaped diamond grinding wheel has a hole (1a) for mounting the rotating shaft in the middle and large part of the drum-shaped metal (11), and a diamond grinding wheel part (2) with a curvature R on the outer peripheral surface. There are two types of noodles, concave and convex in shape, and Fig. 3 shows the concave.Furthermore, Figs. 4 to 7 show the conventional curved surface processing method in the order of steps, A convex piezoelectric material (3) obtained by cutting ceramics using a deformed diamond magnet having a concave curvature R shown in Fig. 3 is shown. Fig. 5 shows a convex piezoelectric material (3) with a 0 curvature. This shows a configuration in which a convex piezoelectric material (3) is attached to a concave R-face block (5+) with the same curvature R on the concave surface through an adhesive (41). The figure shows a state in which a shaped piezoelectric body (3) is cut by rotating and moving a deformed diamond grindstone with a convex curvature R, and a curved piezoelectric body (3) having a surface pressure curved surface in the thickness direction of a rectangular piezoelectric body ( 3a)
It is processed into.

FIG. 1 is a perspective view of a curved vibrator in which electrodes (61) are provided vertically in the thickness direction of the curved piezoelectric body (5a) obtained in this manner.

[Problem that the invention seeks to solve]

In the conventional curved machining method of an ultrasonic pendulum, the machining process of forming an adhesive layer (4) at 5 as shown in FIG. Block (510
Curved piezoelectric material after concave processing due to misalignment (3
A) Thickness variation defects are likely to occur.

There were also five problems in that the diamond body surface moved on the convex piezoelectric body (3), resulting in defects in the curved surface due to positioning errors. Also, when installing it on the electrode (6) after processing the curved surface 1
For example, when a conductive paste is used, the thickness of the electrode becomes uneven due to the paste's own weight when the paste dries, and this curved surface processing method is unsuitable for mass production.

This invention was made in order to solve the above-mentioned problems, and it is an ultrasonic transducer that can easily and reproducibly obtain a curved transducer with reduced thickness variations of nine curved piezoelectric bodies and electrodes. The purpose is to provide a curved surface processing method.

[Means for solving problems]

The method for processing a curved surface of an ultrasonic pendulum according to the present invention includes a step of providing #L poles on both sides of a piezoelectric body processed into a flat plate shape to form a flat plate ultrasonic vibrator, and combining this flat plate ultrasonic vibrator with a concave block and a convex block. A step of heating the flat plate ultrasonic transducer between the blocks to form a nine-curved ultrasonic transducer is performed.

[Effect]

In addition to providing a concave surface on the top surface of the flat ultrasonic transducer, the convex block in this invention also serves as a load, and when heated, causes grain boundary sliding in the flat piezoelectric material and the electrodes, thereby generating a flat ultrasonic transducer. deformation occurs. By receiving the deformation with the concave block, a convex surface is formed on the lower surface of the flat ultrasonic transducer, and a curved surface is processed.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. 1st
The figure is a perspective view for explaining a method for processing a curved surface of a flat plate ultrasonic transducer according to an embodiment of the present invention.

In the figure, (3b) is a flat piezoelectric material, and (7) is a convex block having a curvature R, that is, a 68-sided block.

A concave block having a curvature R, that is, a concave R-plane block (5
) and the 68-sided block (7), there are 1! This figure shows a flat plate ultrasonic transducer with poles.

Here, the material for the convex R [lfi block or concave R surface block is alumina, which does not react with the electrodes.

Ceramic materials such as zirconia, heat-resistant metal materials such as stainless steel, etc. are used.

When a flat ultrasonic transducer is set as shown in FIG. A downward load of l is applied.

An upward load of 501 is applied to each of the two contact line portions with the concave R surface block (5).

When heated in this state, plastic strain occurs on the verge of brittle rupture due to load stress. Strain starts at three locations simultaneously, near the contact line with the 68-sided block (7) and near the contact line with the two concave R-sided blocks, but the strain rate differs by twice the load, so ), the area near the first part of MMII has a speed that is more than twice that of the other two locations. Therefore, the central part of the lithographic ultrasonic transducer begins to distort more quickly. However, as strain occurs, the tangential M line portion gradually has an iiO product, and the strain rate decreases because the load applied per unit area becomes smaller. Such a phenomenon continues continuously, and after a certain period of time, the flat ultrasonic transducer is transformed into a curved transducer having the curvature R of the concave R-plane block (5) and the 68-plane block (7).

By processing the curved surface of the ultrasonic transducer according to the embodiment of the present invention through the above-described steps, a curved ultrasonic transducer with small variations in the thickness of the nine-curved piezoelectric body and small variations in the thickness of the electrodes can be easily obtained.

In addition, as another example, grooves are provided in the 68 faces of the 68-face block (7) around the overnight line to form a 68-face block with grooves (7a), thereby achieving curved surface processing with higher precision. It will be done. Grooved 68-sided block (7a) and flat piezoelectric body (
At the two contact line parts with 3a), the initial maximum bending load is 0.7 times the degree of bending when using the convex R[ll] block (7), and the strain rate is 68-sided block (7). , the concave R surface block (51) and the planar piezoelectric material (3b
) contact in two places? The speed approaches the stop speed near the fM section.

Therefore, by using this grooved 68-sided block (7a), harmonious strain deformation is applied to each contact line portion, and curved surface processing with good curvature accuracy can be obtained. In addition, the groove width in this case is the width of the flat piezoelectric body (3b) and the concave R surface block.
15-40% of the length between the two contact lines.

Further, in the above embodiment, the weight of the 68-sided block (7) or the grooved 68-sided block (7a) can be adjusted during heating.

〔Effect of the invention〕

As explained above, the present invention includes a step of forming a planar ultrasonic transducer by providing electrodes on both sides of a piezoelectric body processed into a flat plate shape, sandwiching the planar ultrasonic transducer between a concave block and a convex block, Since the step of heating and deforming the planar ultrasonic transducer to form a nine-curved ultrasonic transducer is performed, it is possible to easily produce a curved ultrasonic transducer with small thickness variations in the nine-curved piezoelectric body and small thickness variations in the electrodes. Moreover, it is possible to provide a method for processing a curved surface of an ultrasonic transducer that can be obtained with good reproducibility.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a state in the middle of processing to explain a method of processing a curved surface of an ultrasonic transducer according to an embodiment of the present invention;
The figure is a perspective view showing a state in the middle of processing to explain another embodiment of the present invention, Fig. 3 is a perspective view of a deformed diamond grindstone used in the conventional curve (2) processing method, and Fig. 4 7 is a perspective view showing the curved surface force of a conventional ultrasonic transducer in order of process. (3a) - Flat piezoelectric body, (51... concave R surface block. (61... electrode, (7)... 68 surface block,
(7a)...Grooved 68-sided block Note that the same reference numerals in Figure 9 indicate the same or equivalent parts.

Claims (4)

[Claims] (1) Step of forming a flat ultrasonic transducer by providing electrodes on both sides of a piezoelectric body processed into a flat plate shape. This flat ultrasonic vibrator is sandwiched between a concave block and a convex block, and heated to form the flat plate. A method for processing a curved surface of an ultrasonic transducer, which includes performing a step of deforming the ultrasonic transducer to form a curved ultrasonic transducer. (2) A method for processing a curved surface of an ultrasonic transducer according to claim 1, wherein grooves are formed in the convex portion of the convex block around the ridge lines thereof. (3) The method for processing a curved surface of an ultrasonic transducer according to claim 1 or 2, wherein the material of the convex block or the concave block is a ceramic material. (4) The method for machining a curved surface of an ultrasonic transducer according to claim 1 or 2, wherein the material of the convex block or the concave block is a heat-resistant metal material.