JPH04207698A - Production of composite piezoelectric body - Google Patents

Abstract

PURPOSE:To allow the exact and accurate two-dimensionally arrangement of columnar piezoelectric elements by packing an org. high polymer which cures at the temp. near room temp. into grooves like gratings, curing the high polymer and removing at least the uncut planar surface of the piezoelectric body. CONSTITUTION:The grooves 2 are formed like gratings (network) by mechanical working, etc., on the planar piezoelectric body 1 from one surface to form the two-dimensionally arranged columnar parts 3. The planar surface 4 is made to remain without being cut on the other surface. The grooves 2 are so formed that the depth of the grooves, i.e., the height of the two-dimensionally arranged columnar parts 3 of the piezoelectric body 1 attain the finally desired thickness of the composite piezoelectric body or above. The org. high polymer 5 which cures at about room temp. and is increased in glass transition temp. by heating is packed into the grooves 2 of the piezoelectric body 1. The uncut planar surface 4 of the piezoelectric body 1 is removed by polishing, etc., to separate the two-dimensionally arranged columnar parts 3. The piezoelectric elements 6 are exactly and accurately two-dimensionally arranged in this way.

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, probes), which are sensors for sonar and ultrasound diagnostic equipment for water and living organisms. Composite piezoelectric materials are being investigated. Conventionally, in order to manufacture this composite piezoelectric material, for example, Japanese Patent Laid-Open No. 6
1-. A method described in Japanese Patent No. 210799 is known. Hereinafter, the method for manufacturing the conventional composite piezoelectric body will be described with reference to schematic perspective views for explaining the manufacturing process shown in FIGS. 2(a) and 2(bl).

First, as shown in FIG. 2(a), a piezoelectric ceramic plate 20 having a desired thickness is placed on a holding base 20 with wax 21.
2, a cutting groove 23 is formed in the piezoelectric ceramic plate 20 in a lattice shape to a depth of about half the thickness of the piezoelectric ceramic plate 20 using a dicing machine, etc., and a resin 24 is placed in the cutting groove 23.
Fill it with. Next, as shown in FIG. 2(b), the piezoelectric ceramic plate 20 is removed from the holding stand 22, turned over and fixed to the holding stand 22 in the same manner as above, and this piezoelectric ceramic plate 20 is It is cut into a lattice shape so as to reach the grooves 23, and the cutting grooves 25 are filled with resin 26.

After that, by removing these from the holding stand 22,
A composite piezoelectric body 28 can be manufactured by bonding two-dimensionally arranged columnar piezoelectric ceramic elements 27 with resins 24 and 26.

Problems to be Solved by the Invention However, in such a conventional method for manufacturing a composite piezoelectric material, since the piezoelectric ceramic plate 20 is cut approximately in half from the front side and the back side, the cutting grooves 2 on the front side and the back side are cut in half.
3.25 is very difficult in terms of manufacturing technology. As a result, the cutting groove 23.2
5, it becomes impossible to form the piezoelectric ceramic into the desired shape, the vibration form of the piezoelectric ceramic changes, and the characteristics as a composite piezoelectric body deteriorate.

Furthermore, when an epoxy resin that is hard after curing is used as the resin 24, 26, there are problems such as difficulty in forming the desired shape of the composite piezoelectric material, for example, a concave surface. Ta.

The present invention solves these conventional problems, and enables columnar piezoelectric elements to be arranged two-dimensionally with accuracy and accuracy, thereby improving the characteristics of a composite piezoelectric material. It is also possible to prevent distortion and breakage, thus improving the manufacturing yield, and also to form the composite piezoelectric body into a desired shape, thus making the composite piezoelectric body concave. To provide a manufacturing method for a composite piezoelectric material that can be easily processed into a desired shape such as It is an object of the present invention to provide a method for manufacturing a composite piezoelectric material that can be maintained and, therefore, can improve reliability.

Means for Solving the Problems The technical solution of the present invention for achieving the above object is as follows:
Grooves are formed 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 in these grooves are organic polymers that harden at temperatures around room temperature. After curing, at least the uncut plate-like surface of the piezoelectric material is removed.

In addition, grooves are formed in parallel to one surface of a plate-shaped piezoelectric material that is thicker than the final target thickness and deeper than the final target thickness, and these grooves are filled with an organic polymer that hardens at a temperature near room temperature. After curing, grooves are formed in the uncut plate-like surface of the piezoelectric body in a direction orthogonal to the grooves, deeper and parallel than the final target thickness, and these grooves are filled with an organic polymer that hardens at a temperature near room temperature. After curing, at least the uncut portions on both sides of the piezoelectric body are removed.

Further, as the organic polymer that hardens at around room temperature, a material whose glass transition temperature increases when heated can be used, and an epoxy resin can be used as such a material.

Therefore, according to the present invention, a groove is formed deeper than the final target thickness without completely cutting a plate-shaped piezoelectric material thicker than the final target thickness, and an organic material that hardens at a temperature near room temperature is filled in the groove. Since the polymer is filled and cured, and then at least the uncut portion of the piezoelectric body is removed, the piezoelectric elements can be accurately and accurately two-dimensionally arranged.

Further, by using a material that hardens at room temperature as the organic polymer as described above, shrinkage that occurs after curing can be reduced, and distortion and damage to the piezoelectric body can be prevented. Furthermore, by heating the composite piezoelectric material after curing it at room temperature, the organic polymer can be softened and the composite piezoelectric material can be made flexible, so that it can be formed into a desired shape.

In addition, by using a material that increases the glass transition temperature i when heated as an organic polymer, when constructing the transducer, the desired shape can be maintained even when heated as long as the temperature is below the glass transition temperature. can do.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

1(a) to (di) show a method for manufacturing a composite piezoelectric material in one embodiment of the present invention, FIGS. 1(a) to (C1 are schematic perspective views for explaining the manufacturing process, and FIG. 1(di) FIG. 2 is a schematic cross-sectional view for explaining the manufacturing process.

In FIG. 1(a), 1 is a piezoelectric material, for example, P
ZT series, PbTl0. piezoelectric ceramics, LiNb
Using materials like single crystals such as O3 and LiTaO3,
Prepare a plate that is thicker than the final desired thickness. First, this plate-shaped piezoelectric body 1 is processed into a lattice shape (mesh shape) from one side by a mechanical processing method such as a dicing machine or a wire saw, or a processing method using a laser.
A groove 2 is formed in the groove 2 to form a two-dimensional array of columnar parts 3, and a plate-like surface 4 is left uncut on the other surface. At this time, the depth of the groove 2, that is, the height of the columnar portions 3 of the two-dimensional array of the piezoelectric body 1 is formed so that it is greater than or equal to the thickness of the final target composite piezoelectric body.

Next, as shown in FIG. 1 (bl), the grooves 2 of the piezoelectric body 1 are filled with an organic polymer 5 that hardens near room temperature and whose glass transition temperature increases when heated. is a material such as epoxy resin, for example, Structbond EH-454NF and EH-4 manufactured by Mitsui Toatsu Chemical Co., Ltd.
55NF etc. is used. Since this epoxy resin is cured by being left at a temperature near room temperature for 12 hours or more, the curing shrinkage rate is smaller than when it is cured by heating. Therefore, when heated and cured, there is almost no risk of cracking or deformation of the uncut plate-like surface 3 caused by curing shrinkage due to curing shrinkage.Next, as shown in FIG. Plate-like surface 4 due to uncut portion in 1
is removed by a method such as polishing or grinding, and the two-dimensional array of columnar parts 3 is separated. Next, by polishing or grinding the columnar part 3 and the organic polymer 5, the two-dimensionally arranged columnar piezoelectric elements 6 are joined with the organic polymer 5, and the desired thickness, that is, the desired frequency is achieved. A suitable composite piezoelectric body 7 is produced. Next, in order to make the composite piezoelectric body 7 into a desired shape, for example, a concave shape, as needed, as shown in FIG. The piezoelectric body 7 is installed, and the composite piezoelectric body 7 is heated while being pressurized by the mold 8.9, and the composite piezoelectric body 7 is heated.
The organic polymer 5 in is softened. At this time, as mentioned above, the organic polymer 5 uses a material that hardens around room temperature, and the glass transition temperature Tg is not so high.
It softens by heating for a short time at 0-200°C. By softening the organic polymer 5, the composite piezoelectric body 7 is made flexible and can be easily shaped into a desired shape. When an acoustic matching layer, a back load material, etc. are adhered to the composite piezoelectric body 7 formed into a desired shape, and lead wires are taken out to form a transducer, heating may be applied. Therefore, by setting the temperature when heating the composite piezoelectric body 7 while pressurizing it as high as 100 to 200°C as described above, the glass transition temperature T'll of the organic polymer 5 can be increased.
It becomes possible to increase T, and it is possible to prevent changes in shape due to heating during the production of the transducer. Next, after heating and pressurizing the composite piezoelectric body 7 as described above, when the organic polymer 5 is completely cured and the composite piezoelectric body 7 has the desired shape, it is removed from the mold 8.9. Composite piezoelectric material 7
Electrodes are provided on both sides, and lead wires are connected (both not shown). Furthermore, a back load material, an acoustic matching layer, an acoustic lens, etc. are provided as necessary to construct a transducer.

In this way, grooves are formed in the piezoelectric body 1 in a lattice pattern with a depth equal to or greater than the final target thickness, and the grooves are filled with an organic polymer 5 that hardens at around room temperature and cured, and after curing, at least Since the uncut plate-like surface 4 of the piezoelectric body is removed, the piezoelectric elements 6 can be accurately and accurately two-dimensionally arranged. Furthermore, since the organic polymer 5 shrinks less after curing, distortion and damage to the piezoelectric body 1 can be prevented. Moreover, the organic polymer 5 can be softened, and the composite piezoelectric body 7 can be easily formed into a desired shape. In addition, since a material whose glass transition temperature increases when heated is used as the organic polymer 5, it is possible to maintain the desired shape not only at room temperature but also even when slightly heated during assembly of the transducer. I can do it.

In the above embodiment, when a part of the piezoelectric body 1 is left, the grooves 2 are processed in a lattice shape (mesh shape) deeper than the final target thickness, and the grooves 2 are filled with the organic polymer 5. However, in addition to this, a part of the piezoelectric body 1 is left on one side, a groove is machined deeper and parallel to the desired thickness than the final target thickness, and this groove is filled with an organic polymer 5 and then heated at room temperature. After curing, a parallel groove is formed from the other uncut surface of the piezoelectric body in a direction perpendicular to the above groove and deeper than the final target thickness, and this groove is filled with organic polymer 5 and cured at room temperature. , hereafter,
Even if a composite piezoelectric body is manufactured in the same manner as in the above embodiment, the same effects as in the above embodiment can be obtained.

In the above example, after polishing to the final desired thickness and forming a composite piezoelectric material, this composite piezoelectric material is placed in a mold and heated to form the desired shape, and then electrodes are formed on both sides. In addition, after forming a composite piezoelectric material and providing electrodes on both sides, the composite piezoelectric material with the electrodes attached is placed in a mold and heated to form it into the desired shape. The same effect can be obtained.

As described in detail, according to the present invention, a groove is formed deeper than the final target thickness without completely cutting a plate-shaped piezoelectric material thicker than the final target thickness, and the groove is heated at around room temperature. It is filled with an organic polymer that hardens at a temperature of
Since at least the uncut portion of the piezoelectric material is removed, the piezoelectric material elements can be accurately and accurately two-dimensionally arranged. Therefore, the properties of the composite piezoelectric material can be improved.

Furthermore, by using a material that hardens at room temperature as described above as the organic polymer, shrinkage that occurs after hardening can be reduced, and distortion and damage to the piezoelectric body can be prevented. Therefore, manufacturing yield can be improved. In addition, after the composite piezoelectric material is formed by curing at room temperature, heating partially softens the organic polymer and makes the composite piezoelectric material flexible, so it can be shaped into a desired square shape. 4 can be formed. Therefore, the composite piezoelectric body can be easily processed into a desired shape such as a concave surface.

In addition, by using a material whose glass transition temperature increases when heated as an organic polymer, when constructing the transducer, the desired shape can be maintained as long as the temperature is below the glass transition temperature even when heated. be able to. Therefore, reliability can be improved.

[Brief explanation of the drawing]

FIGS. 1(a) to (di) show a method for manufacturing a composite piezoelectric material in an embodiment of the present invention, and FIGS. di is a schematic cross-sectional view for explaining the manufacturing process, and FIGS. Body, 2... groove, 3... columnar part, 4...
- Plate surface, 5...: organic polymer, 6... piezoelectric element, 7... composite piezoelectric material, 8.9... type. Name of agent: Patent attorney Osamu Koebi Two Akibaka Figure 1 (a) Figure 1 (cl.

Claims (4)

[Claims] (1) 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, and the grooves are cured at a temperature near room temperature. A method for manufacturing a composite piezoelectric body, which comprises filling an organic polymer and curing it, and after curing, removing at least an uncut plate-like surface of the piezoelectric body. (2) Form parallel grooves deeper than the final target thickness from one side of the plate-shaped piezoelectric material that is thicker than the final target thickness, and fill these grooves with an organic polymer that hardens at a temperature around room temperature. Then, from the uncut plate-like surface of the piezoelectric body, grooves are formed in a direction orthogonal to the grooves, deeper and parallel than the final target thickness, and these grooves are filled with an organic polymer that hardens at a temperature near room temperature. A method for manufacturing a composite piezoelectric body, which comprises curing the piezoelectric body, and removing at least uncut portions on both sides of the piezoelectric body after curing. (3) The method for manufacturing a composite piezoelectric material according to claim 1 or 2, wherein the organic polymer that hardens at around room temperature is a material whose glass transition temperature increases when heated. (4) The method for manufacturing a composite piezoelectric material according to claim 1 or 3, wherein the organic polymer is an epoxy resin.