JPH01127948A - Manufacture of ultrasonic probe - Google Patents

Abstract

PURPOSE:To keep the radius of curvature of an acoustic lens constant, to equalize an adhesive layer and to prevent the deterioration, etc., of the sensitivity characteristic of an ultrasonic element by heating the ultrasonic element in a state that it is pressed by a block which the radius of curvature is set correctly. CONSTITUTION:With respect to an ultrasonic element whose temporary assembling is ended by applying an adhesive, the rib part 10 of an acoustic lens 2 is fitted and inserted into the through-hole of a cylinder 12. When fitting of the cylinder 12 and a cylinder guide 9 advances, the spherical recessed part of the acoustic lens 2 is pressed against a block which the radius of curvature is set correctly. In this state, a pressurizing shaft 13 is inserted into the through-hole of the cylinder 12, and heated, while pressing it against the ultrasonic element through a rear loading material 3. As a result, the adhesive inserted and held among the acoustic lens 2, a second acoustic matching layer 6, a first acoustic matching layer 5, a piezoelectric vibrator 4 and the rear loading material 3 passes through the inside of the rib pat 10 of the acoustic lens 2, a second acoustic matching layer 6, a first acoustic matching layer 5, the piezoelectric vibrator 4 and the side face of the rear loading material 3 and comes out to a space 11, by which it becomes a uniform adhesive layer and is cured and fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an ultrasonic generator that electrically drives a piezoelectric vibrator to emit ultrasonic waves into a medium and receive reflected echoes reflected from the medium. The present invention relates to a method for manufacturing a probe.

BACKGROUND OF THE INVENTION Conventionally, this type of ultrasonic probe has been constructed as shown in FIG.

In order to efficiently radiate ultrasonic waves to a propagation medium, the ultrasonic element 1 is provided with a back loading material 3 that absorbs unnecessary ultrasonic waves toward the back side of the piezoelectric vibrator 4.

Further, on the front surface of the piezoelectric vibrator 4, a first acoustic matching layer 5 and a second acoustic matching layer 5 are provided.
An acoustic matching layer 6 is provided. Furthermore, an acoustic lens 2 molded from thermoplastic resin is provided on the front surface of the second acoustic matching layer 6 in order to focus the ultrasonic waves. This acoustic lens 2 is provided with a spherical concave portion 8 having a predetermined radius of curvature to maintain an arbitrary focusing distance, and a rib portion 10 is provided on the opposite side. 7 is a lead wire.

In order to assemble the ultrasonic element having the above configuration, adhesive is applied to one surface of the back load material 3, and both surfaces of the piezoelectric vibrator 4, both surfaces of the first matching layer 5, the second matching layer 6, and the acoustic lens 2
Apply adhesive to one flat surface of the Then, the back load material 3 coated with adhesive, the piezoelectric vibrator 4 and the first acoustic matching layer 5
, the second acoustic tethering layers 6 are bonded together and integrated.

Next, the thus-integrated lens is inserted into a recess surrounded by one of the ribs 10 of the acoustic lens 2, and the adhesive is heated and hardened to fix it.

Problems to be Solved by the Invention However, fixing in this manner has several drawbacks. That is, since the acoustic lens 2 is molded from thermoplastic resin, the radius of curvature of the spherical concave portion 8 is slightly different from the desired radius, and the radius of curvature of the spherical concave portion 8 is slightly different from the desired radius.
Since the thickness of the acoustic lens 2 differs depending on the curvature of the acoustic lens 2, the bottom surface of the concave portion surrounded by the rib portion 10 of the acoustic lens 2 is bent in a convex shape. , second acoustic matching layer 6, first acoustic matching layer 5
, the thickness of the adhesive between the piezoelectric vibrator 4 and the back loading material 3 is non-uniform, resulting in poor sensitivity and variations in the ultrasonic elements.

The present invention solves the above-mentioned conventional drawbacks, and aims to maintain the radius of curvature of the acoustic lens accurately and constant, and to make the thickness of the adhesive uniform, thereby preventing deterioration and variation in the sensitivity characteristics of the ultrasonic element. The purpose is to

Means for Solving the Problems The present invention achieves the above object, and its technical means consists of a back loading material, a piezoelectric vibrator having electrodes on both sides, at least one acoustic matching layer, and a thermoplastic resin. An adhesive is interposed between an acoustic lens having a spherical portion on a surface facing the subject, and a block having at least a surface made of a rigid body and having a surface of approximately the same curvature as the acoustic lens is brought into contact with the spherical portion of the acoustic lens; The manufacturing method involves fixing and integrating each component by pressurizing and heating.

Function The present invention fixes each component by pressing and heating a block of surface rigid body whose radius of curvature is set correctly. In addition to correcting the block according to its curvature, the thickness of the adhesive can be made uniform because uniform stress is applied to each component, and poor sensitivity and variations in sensitivity of the ultrasonic element can be prevented.

Furthermore, an acoustic focusing lens made of thermoplastic resin can be easily shaped by heating the resin to its softening point and applying pressure.

Furthermore, heating has the effect of removing internal residual stress generated during resin molding.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a partial sectional view of a fixing jig that embodies the method for manufacturing an ultrasonic probe according to the first embodiment of the present invention.

In the figure, 2 is an acoustic lens with a spherical radius on the surface, 3
4 is a piezoelectric vibrator, 5 is a first acoustic matching layer,
6 is a second acoustic matching layer, and 7 is a lead wire, which constitute an ultrasonic element. This configuration is essentially the same as that shown in FIG.

Reference numeral 9 denotes a cylinder guide which is cylindrical in shape and has a counterbore in the center of one surface. A rigid block 14, which will be described later, is inserted into this counterbore.

Reference numeral 14 denotes a rigid block having a desired spherical radius formed accurately on one side and a cylinder with a half face on the other side. The rigid block 14 is precisely fitted into the counterbore of the cylinder guide 9.

Reference numeral 12 denotes a cylinder, and one side is provided with a counterbore that fits accurately with the cylinder guide 9, and the other side is provided with a through hole.

Reference numeral 13 denotes a pressurizing shaft, one of which is a cylinder with a step, and an escape groove for the lead wire 7 is provided in the longitudinal direction of the side surface. The pressurizing shaft 13 fits accurately into a through hole provided on one side of the cylinder 12.

Next, the operation of the configuration of this embodiment will be explained.

First, as a preliminary work, the ultrasonic elements are temporarily assembled. That is, adhesive is applied to the bottom surface of the concave portion surrounded by the rib portion 10 of the acoustic lens 2.

Next, adhesive is applied to both surfaces of the second acoustic matching layer 6, and the layer is brought into close contact with the bottom surface of the concave portion of the acoustic lens 2 on which the adhesive is applied.

Further, an adhesive is applied to both surfaces of the first acoustic matching layer 5, and the layer is stacked on the second acoustic matching layer 6. Similarly, piezoelectric vibrators 4 are stacked together with an adhesive interposed therebetween. Further, adhesive is applied to one surface of the back load material 3 provided with a relief portion for the lead wire 7, and the piezoelectric vibrator 4 is overlapped with the adhesive.

With the above contents, the temporary assembly of the ultrasonic element is completed.

Of course, the order of assembling the ultrasonic elements is not limited to this.

Next, it is inserted into the fixing jig shown in FIG. 1 and fixed, and the procedure is as follows.

The ultrasonic element, which has been temporarily assembled by applying adhesive, is inserted into a through hole provided on one side of the cylinder 12 by fitting the rib portion 10 of the acoustic lens 2 into the through hole.

At this time, the fit between the rib portion 1o of the acoustic lens 2 and the through hole of the cylinder 12 must not be too loose or too hard.

While the ultrasonic element is fitted and inserted into the through hole of the cylinder 12 in this manner, the cylindrical portion of the cylinder guide 9 is gradually fitted into one of the counterbore portions of the cylinder 12.

By advancing the fitted state between the cylinder 12 and the cylinder guide 9, the spherical recess of the acoustic lens 2 and the surface of the rigid block 14 come into contact.

In this state, the pressure shaft 13 is inserted into a through hole provided in one side of the cylinder 12, and the ultrasonic element is heated while applying pressure with a constant weight through the back load material 3.

As a result, the adhesive sandwiched between the acoustic lens 2, the second acoustic matching layer 6, the first acoustic matching layer 5, the piezoelectric vibrator 4, and the back load material 3 is removed from the inside of the rib portion 10 of the acoustic lens 2 and the second acoustic matching layer 5. By passing through the side surfaces of the acoustic matching layer 6, the first acoustic matching layer, the piezoelectric vibrator 4, and the back load material 3 and exiting into the space 11, a uniform adhesive layer is formed, and in this state, it is hardened and fixed.

Furthermore, since the spherical concave portion of the acoustic lens 2 comes into surface contact with the rigid block 14 and is heated while receiving uniform stress, the rigid block 14 is corrected to have an accurate curvature surface, and is not partially deformed or the overall shape is distorted. There are no other problems. Further, unnecessary convex curvature of the bottom surface of the acoustic lens 2 surrounded by the rib portion 10 is also corrected. Therefore, the focal length of the acoustic lens can be kept accurately and constant at all times, and poor sensitivity and variations in the ultrasonic elements can also be prevented.

Furthermore, the heating temperature is changed by using a heat curing adhesive, the first stage is annealing to correct distortion of the acoustic lens and remove internal residual stress, and the second stage is shaping to adjust the spherical radius shape of the acoustic lens. In the third step, the temperature program is changed in one operation, such as curing and fixing the adhesive, making it possible to manufacture an ultrasonic element with optimal characteristics.

FIG. 2 shows a partially cutaway sectional view of a fixing jig as a second embodiment of the present invention.

The difference between this embodiment and the first embodiment lies in the structure of the block. In this embodiment, the block is a rigid block 16.
and an elastic body 17. The rest is exactly the same as the first embodiment, so a detailed explanation will be omitted, but in this embodiment, a reinforcing square 15 is provided on the bottom surface of the counterbore portion of the cylinder guide 9. This spacer 15 is provided to prevent the elastic body 17 from being damaged when the block is removed.

In the case of this embodiment, the same effects as in the first embodiment can be obtained, but since the block is further composed of a rigid block 16 and an elastic body 17, each of the ultrasonic transducers is affected by the action of the elastic body 17. In addition to being able to apply stress uniformly to the components, the elastic body 17 acts as a buffer even if careless loading is applied at the moment of contact with the block, thereby preventing the piezoelectric vibrator from cracking. can do.

In the above embodiment, an example was described in which the surface of the acoustic lens on the subject side was provided with a spherical concave portion, but it may also be a spherical convex portion, and in this case, the surface shape of the block may also be shaped accordingly. Of course.

Effects of the Invention In short, the present invention provides the following advantages: When bonding each component of an ultrasonic element including an acoustic lens having a spherical portion on the surface on the subject side, the spherical surface of the acoustic lens is bonded to a block having a surface of approximately the same curvature as the acoustic lens. This method has the advantage that the thickness of the adhesive layer between each component can be made uniform, and poor sensitivity and sensitivity variations of the ultrasonic element can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view of a fixing jig embodying the method of manufacturing an ultrasonic probe according to the first embodiment of the present invention, and FIG. Partially broken sectional view of the fixing jig embodying the manufacturing method, Part 3
The figure is a sectional view showing a conventional ultrasonic element. 2...-acoustic lens, 3... back loading material, 4... piezoelectric vibrator, 5... first acoustic matching layer, 6... second acoustic matching layer, 14... rigid block. Name of agent: Patent attorney Toshio Nakao Haka 1st person
1 Figure 13 Exhaust Shaft 7 Lee Jotaku\ / / /? Wrinkle = Ri 2 Fri r No. 2 Figure 13

Claims (1)

[Claims] a piezoelectric vibrator having electrodes on both sides; an acoustic matching layer disposed on one side of the piezoelectric vibrator; an acoustic lens made of thermoplastic resin and having a spherical portion on the surface facing the subject; and the other side of the piezoelectric vibrator. a back loading material disposed on the surface of the acoustic lens, an adhesive is interposed between the back loading material, the piezoelectric vibrator, the acoustic matching layer, and the acoustic lens, and at least the surface of the acoustic lens is made of a rigid body. A method of manufacturing an ultrasonic probe, which comprises bringing a block having a surface of approximately the same curvature as that of an acoustic lens into contact with the acoustic lens, and heating and pressurizing the block.