軸對稱與二維超音波放大器特性之差異

Abstract

超音波技術已相當成熟，尤其是功率超聲的部分，其有許多延伸出來的技術，如超音波切削、超音波焊接、超音波霧化等等，然而由於換能器能轉換的振幅有其極限，故常會加上超音波放大器放大其振幅。本研究主要探討常見的懸鏈線型、指數型、錐體型、傅立葉型這四種放大器，在軸對稱放大器與二維放大器的差異，並討論各參數對其影響。 本文首先描述四種放大器外形曲線的推導過程，而後將其與三維模擬進行比較，了解其一維近似理論與三維模擬的差異，並討論傅立葉放大器參數變化影響，以找尋更佳傅立葉型外形曲線，在討論軸對稱放大器其形狀因子與長度誤差對其行為的影響，由於微機電製程的限制，利用矽晶片製作厚度不變的二維放大器，故討論軸對稱放大器與二維放大器之差異，討論放大器連接換能器或連接多個放大器等對頻率之影響，而後將最後設計放大器透過微機電製程製作，經過量測結果比較，頻率誤差比從 0.12 % ~ 1.77 %不等。

Ultrasonic technology is quite mature, especially in the part of power ultrasound, which has many extended technologies, such as ultrasonic cutting, ultrasonic welding, ultrasonic atomization, etc. However, since the transducer convert the amplitude has its limit. Therefore, an ultrasonic amplifier is often added to amplify its amplitude. This study mainly discusses the differences between the four types of common catenary, exponential, cone, and Fourier amplifiers,and the difference between the axisymmetric amplifier and the two-dimensional amplifier, and discusses the influence of various parameters on it. First,the study describes the derivation process of the four amplifier shape curves, and then compares it with the three-dimensional simulation to understand the difference between the one-dimensional approximation theory and the three-dimensional simulation, and discusses the influence of the Fourier amplifier parameter variation, and has found a better Fourier shape curve. In the discussion of the influence of the shape factor and length error on the behavior of the axisymmetric amplifier, due to the limitation of the microelectromechanical process, the two-dimensional amplifier with the same thickness is fabricated by using the germaniμm wafer. Therefore, the difference between the axisymmetric amplifier and the two-dimensional amplifier is discussed. The effect of the connection of the transducer or the connection of multiple amplifiers on the frequency, and then the final design of the amplifier through the micro-electromechanical process. After the measurement results are compared, the frequency error ratio ranges from 0.12% to 1.77%.