Ultrasonic sensor

Abstract

The object of the present invention is to control the diameter of pores in a coupling layer formed of a ceramic porous body and organic glass. An ultrasonic sensor is provided, comprising a piezoelectric body, a casing for containing the piezoelectric body, and a coupling layer arranged on the top of the casing, wherein the coupling layer is composed of a ceramic porous body with uniform glass spheres in the holes, and the The glass spheres are formed from a dried gel of plexiglass. In the ultrasonic sensor, resin particles (4) containing liquefied gas are added to a slurry (3) using an inorganic material, and the resin particles (4) are foamed in a first heating step to form hollow spherical particles (5) In the second heating step, the ceramic porous body is fired to form plexiglass (7) in the controlled pores, and a coupling layer (9) with stable internal density and constant acoustic impedance is produced, thereby providing a stable output Ultrasonic sensor.

Description

technical field [0001] The invention relates to a coupling layer for improving the acoustic performance of an ultrasonic sensor. Background technique [0002] In the past, the manufacturing method of the coupling layer used in the ultrasonic sensor etc. has the following method: for example, as shown in Figure 6 (a), after mixing microspheres 20 and resin 21 in the container 19, as shown in Figure 6 (b) , together with the container 19 is set in the centrifugal separator 22 to drive it. Then, as shown in Figure 6 (c), in the mixture of glass microspheres 20 and resin 21, use the difference in specific gravity to separate into the first resin layer 21a of glass microspheres with a smaller specific gravity as the main component, and the first resin layer 21a only by comparing the specific gravity. The second resin layer 21b that big resin layer is formed, forms the second resin layer 21b that is only made up of resin layer 21 in the bottom of container 19, forms the first res...

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Problems solved by technology

[0007] However, in this conventional manufacturing method, only the second resin layer used for the coupling member is formed because the first resin layer in which the resin adheres to the periphery of the glass microspheres and the second resin layer in which the main component is only a resin with a relatively high specific gravity are formed. One resin layer, the remaining second resin layer is discarded, so the part that can be taken from the manufactured coupling part is limited, so the production efficiency of the coupling part is less manufacturing method

[0008] In addition, in order to form bubbles with a stable bubble diameter in inorganic materials, bubbles are introduced into the slurry using a mixer or the like, but when the slurry is injected into a rod shape with a certain length like a coupling member, the injection operation is difficult. The air bubbles finally introduced disappear, and the bubble diameter distribution in the coupling part becomes uneven. Therefore, in the coupling layer with a certain thickness taken out from the coupling part, a coupling layer with a uniform bubble diameter cannot be obtained, and the air bubbles in the coupling layer The diameter is not stable, so the ultrasonic wave cannot be effectively transmitted into the air through the coupling layer, so there is a problem that the output of the ultrasonic sensor varies with each coupling layer

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