JPH01127947A - Manufacture of ultrasonic probe - Google Patents

Abstract

PURPOSE:To prevent the damage, etc., of a piezoelectric vibrator at the time of assembly, and also, to equalize an adhesive layer and to prevent the deterioration, etc., of the sensitivity characteristic of an ultrasonic element by heating an acoustic lens in a state that it is pressed against the block of an elastic body. CONSTITUTION:With respect to the ultrasonic element whose temporary assembling is ended by applying an adhesive agent, the rib 10 of the 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 and the surface of an elastic body block 14 is brought into contact with each other. 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 by prescribed weight. 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, the piezoelectric vibrator 4 and the rear loading material 3 passes through the inside of the rib part 1 of an 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 back load material 3 and comes out to a space 11, becomes a uniform adhesive layer thereby, and the deterioration of a sensitivity characteristic of the ultrasonic element can be prevented.

Description

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

2. Description of the Related Art Conventionally, this type of ultrasonic probe has had a configuration 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 matching layers 6 are bonded to each other 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, this method of fixing 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 will be slightly different from the desired radius, and if this is attempted to be corrected during assembly, the piezoelectric vibrator may break or the like. A problem had arisen. Further, since the thickness of the acoustic lens 2 varies depending on the curvature of the spherical concave portion 8, the bottom surface of the concave portion surrounded by the rib portion 10 of the acoustic lens 2 is bent in a convex shape, so that the acoustic lens 2,
a second acoustic matching layer 6, a first acoustic matching layer 5, a piezoelectric vibrator 4,
The thickness of the adhesive between the back loading materials 3 is non-uniform, which has the disadvantage of causing poor sensitivity and variations in the ultrasonic elements.

The present invention solves the above-mentioned conventional drawbacks, and prevents the piezoelectric vibrator from being damaged during assembly, and also makes the thickness of the adhesive uniform to prevent 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 the surface on the side of the subject, and the spherical portion of the acoustic lens is brought into contact with a block made of an elastic body having a surface of approximately the same curvature as the acoustic lens, and heated under pressure. Accordingly, the manufacturing method involves fixing and integrating each component.

Function The present invention fixes each component by heating the acoustic lens while it is pressed against an elastic block.
Even if the acoustic lens is formed with some distortion during molding, the block is made of an elastic material, so it can absorb all the deformation and distortion of the acoustic lens, thereby preventing damage to the piezoelectric vibrator when assembling the ultrasonic element. Can be done. In addition, uniform stress is applied to each component due to the action of the elastic block, so that the thickness of the adhesive can be made uniform, 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 cross-sectional view of a fixing jig embodying a method of manufacturing an ultrasonic probe according to an 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. An elastic block 14, which will be described later, is inserted into this counterbore.

Reference numeral 14 denotes an elastic block, which has a desired spherical radius formed accurately on one side and a cylinder with a flat surface on the other side. The elastic block 14 is precisely fitted into the counterbore of the cylinder guide 9 via the spacer 15. The spacer 15 is for preventing deformation and damage of the elastic block 14, and is made of a rigid body.

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 cylindrical cylinder with a step, and has an escape groove for the lead wire 7 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 elastic block 14 come into contact.

In this state, the pressurizing shaft 13 is inserted into a through hole provided on one side of the cylinder 2, 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 jO 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 15, a uniform adhesive layer is formed, and in this state, it is hardened and fixed.

Furthermore, the spherical concave portion of the acoustic lens 2 is connected to the elastic block 1.
4, the entire surface is heated while being subjected to uniform stress, so there are no problems such as partial deformation or distortion of the overall shape. Moreover, the piezoelectric vibrator 4 and the like are not damaged due to the buffering effect of the elastic block 14. Therefore, the focal length of the acoustic lens can be kept accurately and constant at all times, and damage to the piezoelectric vibrator and poor sensitivity and variations in the ultrasonic element 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.

In the above embodiments, the elastic material may be any material having elasticity, such as silicone rubber, urethane rubber, neoprene rubber, or the like. Especially with silicone rubber, there is no need to worry about the elastic body sticking even if the adhesive accidentally sticks to it.

In the above embodiment, the object-side surface of the acoustic lens is 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 will be shaped accordingly. Of course.

Effects of the Invention In summary, the present invention provides an acoustic lens to an elastic block having a surface of approximately the same curvature as the acoustic lens when bonding each component of an ultrasonic element including an acoustic lens having a spherical portion on the surface on the side of the subject. A uniform adhesive layer can be obtained in the process of configuring the element part of an ultrasonic probe by bringing the spherical part of the A well-dispersed bonding state can be ensured, and in the past, if each component had small convexities, stress would concentrate on the convexities and the piezoelectric vibrator would crack, or even pressure could not be measured and the thickness of the adhesive layer would be reduced. However, by using an elastic body, the elastic body absorbs small protrusions, which solves the above problem, improves work efficiency, and drastically reduces the occurrence of defects during the process. However, it has the advantage of being able to prevent poor sensitivity and sensitivity variations of the ultrasonic element.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view of a fixing jig embodying a method for manufacturing an ultrasound probe according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional ultrasound element. 2... Acoustic lens, 3... Back loading material, 4... Piezoelectric vibrator, 5... First acoustic matching layer, 6... Second acoustic matching layer, 14... 5J body block. Name of agent: Patent attorney Toshio Nakao (1st person)
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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; 1. A method of manufacturing an ultrasonic probe, which comprises bringing an elastic block having a curved surface into contact with each other and applying pressure and heating.