Piezoelectric block for ultrasonic probe, ultrasonic array probe, preparation method of piezoelectric block, and preparation method of ultrasonic array probe

Abstract

The invention is applicable to the technical field of medical instruments, and provides a piezoelectric block for an ultrasonic probe. The piezoelectric block comprises a plurality of piezoelectric array elements arranged in an array, wherein the piezoelectric array elements have an upper surface and a lower surface that are both provided with electrodes, the upper surface is inclined relative tothe lower surface to uniformly gradually change the thickness of the piezoelectric array elements, and the plurality of piezoelectric array elements are arranged in parallel according to the same thickness variation tendency, so that the upper surfaces of the plurality of piezoelectric array elements form a slope and the lower surfaces of the plurality of piezoelectric elements form a bottom surface. The piezoelectric block provided by the invention is formed by a plurality of piezoelectric array elements with uniformly changed thickness, so that the thickness of the piezoelectric block is uniformly changed, and the thickness of the piezoelectric array elements affects the electromechanical coupling coefficient, thereby affecting the resonance frequency and the bandwidth. Since the thickness of the piezoelectric array elements is gradually thinned, a gradual change is brought in the resonance frequency, so that the bandwidth is increased. And the impedance value at the resonant frequency will become smaller, closer to the 50 ohm electrical matching resistor, which is beneficial to the improvement of sensitivity and imaging quality. 本发明适用于医疗器械技术领域，提供了一种用于超声探头的压电块体，包括阵列排布的多个压电阵元，压电阵元设有上表面和下表面，上表面和下表面均设有电极，上表面相对下表面倾斜使压电阵元的厚度均匀渐变，多个压电阵元按照相同的厚度变化趋势并列排布，使多个压电阵元的上表面形成斜面，使多个压电阵元的下表面形成底面。本发明的压电块体由多个厚度均匀渐变的压电阵元形成，使压电块体的厚度均匀渐变，压电阵元的厚度影响机电耦合系数，进而影响谐振频率及带宽，由于压电阵元的厚度逐渐变薄，因此引起谐振频率的渐变，使得带宽增大。且谐振频率处阻抗值会变小，更接近50欧姆的电学匹配电阻，有利于灵敏度的提高，提升了成像质量。