JPS6321043A - Ultrasonic probe and its production - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ultrasonic probe used in a medical ultrasonic diagnostic apparatus and a method for manufacturing the same.

Conventional technology Recently, convex ultrasound probes with a predetermined curvature have become popular in fields such as medical ultrasound diagnostic equipment due to their ability to expand the detection area compared to linear scanning ultrasound probes. Conventional methods for manufacturing convex ultrasonic probes that have come to be used include, for example, Japanese Patent Application Laid-Open No. 59-20205.
A manufacturing method described in Publication No. 8 is known. Hereinafter, a conventional method for manufacturing a convex ultrasonic probe will be explained with reference to FIG.

A piezoelectric vibrator η having an electrode provided on a first back load material 21 having a thickness of about one inch and made of flat ferrite rubber.
Glue. This piezoelectric vibrator n is cut at regular pitches by a known cutting machine having a diamond wheel to form a piezoelectric vibrator array 22a on the first back load material 21. Next, the gap formed between the piezoelectric vibrator arrays 22a is filled with a synthetic resin n such as polyurethane resin. After the filled synthetic resin n is cured, an acoustic matching layer 24 is poured onto the piezoelectric vibrator array 22a and polished to a predetermined thickness.Next, the first back loading material 21
Similarly, the first back load material 21 is bonded to the second back load material 5 which is made of ferrite rubber and has a curved surface of the curvature to be finally formed. Accordingly, the first back load material 21
is curved along the curvature surface of the second back loading material 5, the piezoelectric vibrator array 22a on the first back loading material 21 is curved at regular intervals, and the acoustic matching layer U is also curved along the piezoelectric vibrator array 22a. curve along. Next, the second back loading material 5 is adhered to a holding base 26 made of aluminum or the like. Thereafter, a flexible wiring board (not shown) is placed along the piezoelectric vibrator array 22a, and each electrical terminal thereof is connected to the piezoelectric vibrator array 22a by brazing or the like.

As a method for forming the piezoelectric vibrator array 223 to have a desired curvature, there is also a method of adhering piezoelectric vibrators having the desired curvature to the back load material in advance, and then cutting the piezoelectric vibrators into multiple pieces in an array shape. According to this method, it is difficult to form a piezoelectric vibrator having a curvature and to cut and divide it into an array, so the above method is mostly used at present. The above method is basically the same as the method for manufacturing a transducer array for a linear scanning ultrasonic probe, but in order to easily bend the transducer array to a desired curvature,
The main difference is that the second back load material 5 is made thinner and bonded to the second back load material 5 having a desired curvature. this is,
This is because ferrite rubber is used as the back load material. In other words, the sound wave attenuation coefficient of ferrite rubber is 3M.
At H2, about 10 dB/drink, first back load material 21
The thickness of this back load material 2 (1 to 3 mm) is insufficient.
Since it is not possible to attenuate unnecessary sound waves incident on 1, a second back loading material 5 made of the same material is required.

Problems to be Solved by the Invention However, in the conventional manufacturing method described above, ferrite rubber is used for the first back load material 21. Since this ferrite rubber does not have sufficient hardness, piezoelectric vibration The child arrays 22a cannot be arranged uniformly, and even if they are bonded to the second back load material 5 with the desired curvature, the individual arrayed piezoelectric vibrators 22a cannot be arranged uniformly to the curvature of the second back load material 5. It is difficult to align. Therefore, it becomes impossible to control the ultrasonic beam with high precision, and it is impossible to obtain an ultrasonic image with a good S/N ratio. In addition, due to acoustic mismatch, sound waves are reflected from the boundary between the adhesive layers bonding the first and second back loading materials 21 and 5 to the piezoelectric vibrator array 22a.
However, there are problems in that these sound waves become noise in the ultrasound image and cause image deterioration.

Therefore, the present invention solves the above-mentioned problems of the prior art, and enables piezoelectric vibrator arrays to be easily and precisely constructed along a desired curved surface, and with a good S/N ratio. The present invention aims to provide an ultrasonic probe that can obtain accurate ultrasonic images, and a method for manufacturing the same.

Means for Solving the Problems The ultrasonic probe of the present invention for solving the above problems is mainly composed of a polymer material whose hardness decreases when heated and has a large acoustic wave attenuation coefficient. A plurality of piezoelectric vibrators are arranged on one surface of the back load material, and the back load material and the piezoelectric vibrators are curved into a desired curved surface.

Furthermore, the method for manufacturing an ultrasonic probe of the present invention includes a piezoelectric vibrator provided with an acoustic matching layer as required, which is made of a polymeric material whose hardness decreases by heating and whose main component is a high acoustic attenuation coefficient. A back loading material is provided, the piezoelectric vibrator is divided into a plurality of pieces from the opposite side of the back loading material, and the back loading material is heated to curve the laminate to a desired curvature.

action The effects of the above technical means are as follows.

In other words, since the back-loading material has high hardness at room temperature, the piezoelectric vibrator array can be constructed along a desired curved surface with high precision, and since the back-loading material has a large acoustic attenuation coefficient, the S/N ratio can be improved. Good ultrasound images can be obtained. Furthermore, since the backside loading material can be made softer by lowering its hardness by heating, the piezoelectric vibrator array can be easily curved along a desired curved surface.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings. ◇ Figures 1 (a), (b), (e), and (d) are cross-sectional views for detailed explanation of the present invention. be.

As shown in FIGS. 1(a) and (bl), electrodes 2.3 are provided on both sides of the piezoelectric element 1 by vapor deposition or baking to form a plate-shaped piezoelectric vibrator 4, and this piezoelectric vibrator Multiple flexible electrical terminals 5.6 are connected to one side of electrode 2.3 of 4 by soldering or conductive adhesive. Next, the epoxy resin is filled with tungsten powder, etc., and the acoustic impedance value is adjusted. A first acoustic matching layer 7 is poured on the surface of the piezoelectric vibrator 4 opposite to the surface to which the electrical terminals 5.6 are connected, or is provided with an adhesive. A back loading material 8 is provided on the opposite side of the layer 70 by bonding or pouring, covering a part of the electrode 5.6.The piezoelectric vibrator 4 is first provided with the back loading material 8, and then the first An acoustic matching layer 7 may be provided.The back loading material 8 is made of a polymeric material, epoxy resin, as a main component, and filled with tungsten powder and microballoons.

The sound wave attenuation coefficient can be changed arbitrarily by adjusting the filling ratio of tungsten powder and microballoon.
Set to dB/lrrm - This is a value approximately 2.6 times larger than that of conventional ferrite rubber.

For example, the dynamic range of the main unit is 150 d.
If B exists, the back load material 8 must provide attenuation of 150 dB or more. Therefore, the thickness of the back loading material 8 should be approximately 3 mm.

Next, as shown in FIG. 1(b), the first acoustic matching layer 7, the piezoelectric vibrator 4, and the electric terminals 5, 6 are cut using a dicing saw or the like.
and part of the back load material 8 are cut at desired intervals,
A plurality of piezoelectric vibrator arrays 4a are formed on the back load material 8.

Next, the back load material 8 is heated to a temperature of 90 to 100 C,
Figure 1 (C)
As shown in the figure, the adhesive is attached along the curved surface of an aluminum holding base 9 having a desired curved surface. Thereby, the laminate consisting of the piezoelectric vibrator array 4a, the first acoustic matching layer 7, and the back load material 8 can be curved along the curved surface of the holding table 9. At room temperature after adhesion, the backside load material 8 has high hardness and is resistant to mechanical shock.

The hardness of the epoxy resin that is the main component of the back loading material 8 is extremely hard with a Shore D of 85 at room temperature, but it is 90
At ~100C, the Shore D becomes 40 or less, making it considerably soft. This tendency is the same when tungsten powder and microballoons are filled.

Next, as shown in FIG. 1(d), a second acoustic matching layer 10 made of epoxy resin or the like is adhered onto the first acoustic matching layer 7, and a silicone An acoustic lens 11 made of rubber or the like is provided. Further, although not shown, electrical terminals 5.6 are connected to a cable. In this way, an ultrasonic probe with a curved transducer array 4a can be obtained.

Since the back load material 8 is made of a material with a large sound wave attenuation coefficient, the thickness can be reduced to about 3 layers, so the back load material 8 can be configured as a single layer, and therefore can be configured as a two-layer structure. There is no multiple reflection at the boundary surface such as the back loading material of the structure9, and there is no deterioration in the resolution of ultrasound images.

In addition, by heating the back load material 8, the hardness decreases and it becomes softer, so that it is possible to easily curve the vibrator array 4a into a required curved surface, and moreover, the piezoelectric vibrator array 4a can be accurately curved. Can be arranged well.

In the above embodiment, a so-called compex-type ultrasonic probe in which the piezoelectric transducer array 4a is arranged in a convex shape is manufactured. It is clear that it can be implemented in sonic probes.

Furthermore, in the above embodiment, the case where the back loading material 8 is mainly composed of epoxy resin and filled with tungsten powder and microballoons is explained, but the main component is polyvinyl chloride 1, polyurethane, etc. A similar effect can be obtained using a polymer material.

Effects of the Invention As is clear from the above description, according to the present invention, a back loading material that can be softened by lowering its hardness by heating and has a large acoustic wave attenuation coefficient is used. Therefore, by heating and softening the back loading material, the piezoelectric vibrator array provided on the back loading material can be freely and easily formed into a required curved surface.

Furthermore, since the backside loading material has high hardness at room temperature, piezoelectric vibrators can be arranged with high precision, and an ultrasonic probe that is resistant to mechanical shock can be obtained. Furthermore, since the back loading material has a large sound wave attenuation coefficient, it is possible to obtain a high resolution ultrasonic image.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1(a), (b), (C), and (d) show the manufacturing order of an ultrasonic probe in an embodiment of the present invention.
1 is a cross-sectional view of the piezoelectric vibrator with electrical terminals connected to its electrodes and the piezoelectric vibrator laminated with the first acoustic matching layer and the back load material, and (b) of the same figure is a cross-sectional view of the piezoelectric vibrator with the piezoelectric vibrator arranged in an array. A vertical cross-sectional view of the formed state; FIG. A schematic vertical cross-sectional view of a completed manufactured state with a second acoustic matching layer and an acoustic lens provided thereon, and FIG. 2 is a schematic vertical cross-sectional view of a conventional ultrasonic probe. l...Piezoelectric element, 2 .3... Electrode, 4... Piezoelectric vibrator, 4a... Piezoelectric vibrator array, 5.6... Electrical terminal, 7... First acoustic matching layer, 8... Back load Material, 9... Holding stand, 10... Second acoustic matching layer, 11
...acoustic lens. Name of agent: Patent attorney Toshio Nakao and one other person (?A) (Figure 1, Figure 2)

Claims (5)

[Claims] (1) A plurality of piezoelectric vibrators are arranged on one side of a back-loading material whose main component is a polymer material whose hardness decreases when heated and has a large sound attenuation coefficient. An ultrasonic probe characterized in that a vibrator is curved into a desired curved surface. (2) The ultrasonic probe according to claim 1, wherein the backside loading material is a single layer. (3) The ultrasonic probe according to claim 1 or 2, wherein the polymer material constituting the back loading material is epoxy resin, polyvinyl chloride, or polyurethane. (4) A piezoelectric vibrator provided with an acoustic matching layer as necessary,
A back-loading material whose main component is a polymer material whose hardness decreases when heated and a high acoustic wave attenuation coefficient is provided, and the piezoelectric vibrator is divided into a plurality of pieces from the opposite side of the back-loading material. A method for manufacturing an ultrasonic probe, comprising heating the material to curve the laminate to a desired curvature. (5) The method for manufacturing an ultrasonic probe according to claim 4, wherein the polymeric material constituting the back loading material is epoxy resin, polyvinyl chloride, or polyurethane.