Ultrasonic transducer, acoustic impedance matching layer and preparation method of acoustic impedance matching layer

Abstract

The invention discloses an ultrasonic transducer, an acoustic impedance matching layer and a preparation method of the acoustic impedance matching layer. The acoustic impedance matching layer comprises magnetic particles coated with a low-density material layer and an adhesive, wherein the magnetic particles coated with the low-density material are in graded distribution in the adhesive based on different acoustic impedance, such that the acoustic impedance of the acoustic impedance matching layer are in gradient distribution from one end to the other end. The preparation method of the acoustic impedance matching layer is appropriate in difficulty. Operation equipment is simple. The prepared acoustic impedance matching layer is in uniform gradient variation of acoustic impedance, has an accurately controllable thickness, can improve the transmission efficiency of acoustic waves in the ultrasonic transducer and improves the sensitivity and the bandwidth of the ultrasonic transducer.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic transducers, in particular to an ultrasonic transducer, an acoustic impedance matching layer and a preparation method thereof. Background technique [0002] In biomedical ultrasound engineering, a large amount of acoustic energy is lost due to impedance mismatch between the piezoelectric layer with high acoustic impedance (about 30 MRayl) and the working medium with low acoustic impedance (about 1.5 MRayl). In addition, the significant difference in impedance will also cause the piezoelectric element to resonate with a high Q value, resulting in longer pulse width and narrower bandwidth, which seriously affects the sensitivity, axial resolution and information richness of the ultrasonic transducer. In order to solve this problem, the method of installing a matching layer between the piezoelectric layer and the working medium is often used for product preparation. In order to ensure the matchin...

AI Technical Summary

Problems solved by technology

[0004] 1) There is still an impedance mismatch between the matching layers, resulting in energy loss;

[0005] 2) Since the transmitted wave is a pulse wave, which contains a variety of frequency components, the wavelength difference in the matching layer is large, and the theoretical thickness calculated according to λ / 4 is also different. The thickness of the matching layer with a fixed thickness will inevitably lead to Acoustic waves with different frequency components produce different losses in the matching layer, causing signal integrity problems;

[0006] 3) The frequency of the high-frequency ultrasonic transducer is high, and the thickness of the matching layer calculated according to the λ / 4 theory is small, the processing technology is more difficult, and the precision is difficult to control

[0007] The best way to solve the above problems is to prepare matching layer materials with gradual impedance changes. However, according to the relevant patents published at present, some matching layer materials are difficult to prepare or cannot be obtained with continuous and uniform impedance changes. More importantly, matching layer materials The thickness of the layer cannot be precisely controlled, which makes the preparation of later products more difficult (such as array element cutting, etc.)

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