JPH04200097A - Manufacturing method of composite piezoelectric material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a composite piezoelectric material used in sensors such as sonar and ultrasonic diagnostic equipment.

Conventional technology Recently, piezoelectric ceramics and organic materials have been combined as piezoelectric materials used in transducers (ultrasonic probes), which are sensors such as sonar and ultrasound diagnostic equipment for water and living organisms. Composite piezoelectric materials are being studied. Conventionally, in order to manufacture this composite piezoelectric material, for example, Japanese Patent Laid-Open No. 60
A method described in Japanese Patent No.-85699 is known. The method for manufacturing the conventional composite piezoelectric material described above will be explained below as shown in Fig. 3 (
This will be explained with reference to schematic perspective views for explaining the manufacturing process shown in a) to (C+).

First, as shown in FIG. 3 (bl), grid-shaped grooves 32 are formed on one surface of the piezoelectric ceramic plate 31 shown in FIG. After filling the grooves 32 with epoxy resin 34 and curing it by heating, the remaining plate-like surfaces 33 are polished and removed, thereby forming the two-dimensional array of columnar piezoelectric ceramic elements 35 into epoxy resin 34. A composite piezoelectric body can be produced by bonding with

Problems to be Solved by the Invention However, in such a conventional method for manufacturing a composite piezoelectric body, the grooves 3 formed in a lattice shape in the piezoelectric ceramic plate 31
By filling the epoxy resin 34 into the epoxy resin 34 and curing it by heating, the reaction curing shrinkage of the epoxy resin 34 is added to the shrinkage due to the cooling of the epoxy resin 34 that has been cured in the heated state. Due to these contractions, the piezoelectric ceramic element 35 after hardening causes a dimensional difference in its thickness direction, and a large warpage 36 as shown in FIG. In some cases, cracks 37 and the like occur, making it impossible to produce a desired composite piezoelectric body. Furthermore, even if cracks do not occur, the warpage 36 causes a decrease in accuracy during polishing, and it becomes necessary to form the groove 32 deeper by the warpage 36, resulting in a decrease in yield during cutting and a decrease in the yield during cutting. There was also the issue of not causing performance deterioration of the composite piezoelectric material.

The present invention solves these conventional problems, and can suppress the occurrence of warping and cracking when filling and curing organic polymers in the grooves, and also reduce the depth of the grooves formed in the piezoelectric material. Moreover, it is possible to minimize the damage, and to easily and accurately produce a composite piezoelectric material. Therefore, it is possible to improve the manufacturing yield, and also to improve the characteristics of the composite piezoelectric material. To provide a method for manufacturing a composite piezoelectric material that makes it possible to improve the heat resistance, cold/heat cycle resistance, etc. of the composite piezoelectric material, thereby improving the reliability of the composite piezoelectric material. It is an object of the present invention to provide a method for manufacturing a composite piezoelectric material that enables the following.

The technical solution of the present invention to achieve the object described in item 1 of ``Means for Solving the Problems'' is to reduce the thickness from one side of a plate-shaped piezoelectric material, which is thicker than the final target thickness, to the same thickness as the final target thickness. Grooves are formed in a lattice pattern with a depth above, and the grooves are filled with an ultraviolet-curable organic polymer and cured by ultraviolet irradiation. After curing, the uncut plate-like surface of the piezoelectric body is removed. This is what I did.

In addition, grooves are formed in a lattice pattern from one side of the plate-shaped piezoelectric material, which is thicker than the final target thickness, to a depth equal to or greater than the final target thickness. Molecules are filled and cured by ultraviolet irradiation, and after curing, the uncut plate-like surface of the piezoelectric body is removed, and then the ultraviolet and heat curable organic polymer is cured by heating.

Therefore, according to the present invention, the grooves formed in a lattice shape with a portion left in the piezoelectric body are filled with an ultraviolet curable organic polymer and cured by ultraviolet irradiation, so that it can be cured at room temperature. It is possible to minimize the amount of shrinkage that occurs after curing, suppress the occurrence of warpage and cracks, and because it can be cured in a flat state, the depth of the grooves formed in the piezoelectric material can also be minimized. It is possible to easily and accurately produce a composite piezoelectric body.

In addition, by filling the grooves of the piezoelectric body with an organic polymer that can be cured with ultraviolet heat, it is first cured with ultraviolet light, the uncut portion of the piezoelectric body is removed, the piezoelectric elements are separated, and then the piezoelectric body is heated. Since it can be cured to shift the glass transition point to a high temperature, it is possible to improve the heat resistance and cold/heat cycle resistance of the composite piezoelectric material.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described.

FIGS. 1(a) to 1(d) are schematic perspective views for explaining the manufacturing process, showing a method for manufacturing a composite piezoelectric body in a first embodiment of the present invention.

In FIG. 1(a), ■ is a plate-shaped piezoelectric material, for example, PZT type, PhT+O, type (7) piezoelectric Cefmix, LiNb0. , LiTa0. Prepare a plate-like material that is thicker than the final desired thickness using a material such as a single crystal. First, as shown in FIG. 1 (bl), the piezoelectric body 1 is processed into a lattice shape (one-mesh shape) from one side by a mechanical processing method such as a die sink machine or a wire saw, or a processing method using a laser. A groove 2 is formed in the columnar part 3 of the piezoelectric body 1 to form a two-dimensional array of columnar parts 3, and a plate-like surface 4 is left uncut on the other surface. Then, as shown in Figure 1 (C1), an organic polymer that cures with ultraviolet rays is added to the groove 2 of the piezoelectric body 1. Fill with curable resin 5.

As this ultraviolet curable resin 5, for example, ultraviolet curable resin XNR5440 manufactured by Nippon Ciba Geigy Co., Ltd. is used. This ultraviolet curable resin 5 has a -liquid property of 250 to 4
It hardens in a few seconds by irradiating it with 0Qnn ultraviolet light. As for the curing conditions, since it can be cured at room temperature, it can be cured with a considerably smaller amount of M yield than when it is cured by heating as in the conventional example.

Next, the uncut plate-like surface 4 of the piezoelectric body 1 is removed by polishing or grinding, as shown in FIG.
As shown in FIG. 2, the two-dimensional array of columnar piezoelectric elements 6 is separated by separating the two-dimensional array of columnar parts 3, and then polishing or grinding the columnar parts 3 and the ultraviolet curing resin 5 as necessary. A composite piezoelectric body 7 having a desired thickness, that is, a desired frequency, can be produced by bonding them together with an ultraviolet curable resin 5.

After this, although not shown, electrodes are provided on both sides of the composite piezoelectric body 7, lead wires are connected to these electrodes, and a back load material, an acoustic matching layer, an acoustic lens, etc. are provided as necessary. This allows it to be configured as a transducer.

As described above, according to the above embodiment, the groove 2 formed by leaving one side of the piezoelectric body 1 uncut is filled with the ultraviolet curable resin 5, and is cured by irradiating ultraviolet rays at room temperature. The amount of shrinkage after curing of this ultraviolet curable resin 5 is only the curing reaction shrinkage of the resin itself, and since this amount of shrinkage is small, it can be cured in a flat state without warping or cracking due to shrinkage. can be made,
It is possible to improve the accuracy during polishing. Also,
Since it is flat, the amount removed during polishing can be minimized, so the depth of the groove 2 can be made shallow when grooving by dicing or the like. Therefore, there is an advantage that a highly accurate composite piezoelectric body 7 can be easily produced.

Furthermore, in the production of high-definition composite piezoelectric bodies, the convergence of the grooves 2 also becomes narrower, making it difficult to fill with the resin material. On the other hand, the resin before curing has a characteristic in its shell that its viscosity decreases as the temperature increases. Therefore, by heating the grooved piezoelectric body 1 to 60 to 70°C and filling the grooves 2 with the ultraviolet curable resin 5, the resin material can be filled with its viscosity reduced. It also has the advantage that it can be easily filled without the resin curing progressing due to this heat.

Next, a second embodiment of the present invention will be described.

FIGS. 2(a) to 2(d) are schematic perspective views for explaining the manufacturing process, showing a method for manufacturing a composite piezoelectric body in a second embodiment of the present invention.

In this embodiment, instead of the ultraviolet curable resin 5 of the first embodiment, an ultraviolet and heat curable resin 8, such as XNR5440TC manufactured by Nippon Diva Geigy Co., which is cured by both ultraviolet rays and heat, is used. In the present invention, similarly to the first embodiment, the piezoelectric body 1 shown in FIG.
As shown in Figure 2 (bl), lattice-shaped grooves 2 are formed,
As shown in FIG. 2 (C1), the groove 2 is filled with an ultraviolet-thermal curable resin 8 and cured by irradiating ultraviolet rays.Next, the uncut plate-like surface 4 of the piezoelectric body 1 is polished, etc. As shown in FIG. 2(d), the two-dimensionally arranged columnar parts 3 are separated, and then heated at about 100° C. for about 40 minutes to heat and harden the ultraviolet and heat curable resin 8. At this time, the columnar part 3 has already been completely separated, so there is no risk of warping even when the temperature rises or falls.After this, the columnar part 3 and the ultraviolet heat curing resin 8 are polished or ground. By bonding the two-dimensional array of columnar piezoelectric elements 6 with ultraviolet thermosetting resin 8, it is possible to produce a composite piezoelectric body 7 having a desired thickness, that is, matching the desired frequency. This work such as polishing can also be performed before the ultraviolet and heat curable resin 8 is cured.

As described above, according to this embodiment, the groove 2 is filled with the ultraviolet and heat-curable resin 8, which is cured by ultraviolet irradiation, and after the piezoelectric body 1 is completely separated by polishing or the like, the resin is heated and cured. As a result, the glass transition point of the ultraviolet and heat curable resin 8 filled in the groove can be shifted to a high temperature. Thereby, the composite piezoelectric body 7 can improve its heat resistance, cold and heat cycle resistance, and the like. Therefore, it has the advantage that a highly reliable composite piezoelectric body can be easily manufactured.

As described in detail, according to the present invention, ultraviolet-curable organic polymer is filled in the grooves formed in a lattice shape, leaving a portion of the piezoelectric body, and is cured by ultraviolet irradiation, so that it cures at room temperature. The amount of shrinkage that occurs after curing can be minimized, and the occurrence of warping and cracks can be suppressed.Also, since it can be cured in a flat state, it is possible to minimize the amount of shrinkage that occurs after curing. The depth can also be suppressed to the necessary minimum, and a composite piezoelectric material can be manufactured easily and with high precision.

Therefore, manufacturing yield can be improved,
Further, it has an effect such that a composite piezoelectric body with improved characteristics can be manufactured.

In addition, by filling the grooves of the piezoelectric body with an organic polymer that can be cured with ultraviolet heat, it is first cured with ultraviolet light, the uncut portion of the piezoelectric body is removed, the piezoelectric elements are separated, and then the piezoelectric body is heated. Since the glass transition point can be shifted to a high temperature by curing, it is possible to improve the heat resistance, cold/heat cycle resistance, etc. of the composite piezoelectric material. therefore,
In addition to the above-mentioned effects, it is possible to manufacture a composite piezoelectric body with improved reliability.

[Brief explanation of the drawing]

FIGS. 1(a) to (d+) are schematic perspective views for explaining the manufacturing process showing the method for manufacturing a composite piezoelectric material in the first embodiment of the present invention, and FIGS. 2(a) to (d) are A schematic perspective view for explaining the manufacturing process showing the method for manufacturing the composite piezoelectric body in the second embodiment, FIGS. It is a perspective view. 1... piezoelectric body, 2... processed groove, 5... ultraviolet curable resin, 6... columnar piezoelectric element, 7... composite piezoelectric substance, 8... combined use with ultraviolet heat. Curing resin. Name of agent: Patent attorney Akira Okaji Two idiots Figure 1 Figure 2

Claims (2)

[Claims] (1) Form grooves in a lattice pattern from one side of a plate-shaped piezoelectric material thicker than the final target thickness to a depth equal to or greater than the final target thickness, and fill these grooves with UV-curable organic polymer. A method for manufacturing a composite piezoelectric body, which comprises filling the piezoelectric body with a compound and curing it by irradiating ultraviolet rays, and removing the uncut plate-like surface of the piezoelectric body after curing. (2) Form grooves in a lattice pattern from one side of the plate-shaped piezoelectric material that is thicker than the final target thickness to a depth equal to or greater than the final target thickness, and fill these grooves with ultraviolet and heat-curable organic A method for manufacturing a composite piezoelectric material, in which a polymer is filled and cured by ultraviolet irradiation, and after curing, the uncut plate-like surface of the piezoelectric material is removed, and then an ultraviolet and heat-curable organic polymer is heat-cured. .