相位式線陣列超音波換能器幾何參數對聲場之影響

超音波量測系統在水利及海洋工程、非破壞檢測、醫療等領域應用已行之有年。其中超音波換能器又是系統中的重要元件之一。換能器，顧名思義即是將不同形式的能量彼此轉換，例如壓磁換能器、壓電換能器等。超音波換能器屬於壓電換能器，在進行分析時常需要機械與電子電路相關知識才能完整描述，因此國內外有許多領域的學者根據各式各樣的模擬方法，結合不同的模擬軟體或演算法，建立能夠表示真實系統的模型，如此一來能省去試誤法所需支出的成本。除了模擬方法以外，聲學材料的實際製造、選擇也深深影響著成品設計的優劣。而單一個換能器所能夠的輻射出的聲波能量有限，因此不管在醫療上或是工程上的應用會朝向以陣列式的方式，使聲束能夠達到最佳的建設性干涉以達到能量較集中的目的。本研究透過模擬以探討不同幾何參數對於相位式線陣列超音波換能器的聲場之影響，探討的參數包括：陣元間距、陣元寬度、陣元長度以及陣元個數。本研究在實驗室中自行製造超音波換能器，並將數個陣元組合成一維線陣列的形式，利用一發一收系統實際量測換能器的指向性，找出陣列超音波換能器的指向性趨勢。並藉由模擬的方式將實驗的結果作比較與驗證並證明其可行性。研究中也歸納出了相位式線陣列設計的最佳規格，希望能提供未來其相關設計一些參考。

關鍵字

壓電式超音波換能器；線陣列；指向性；聲場

並列摘要

Ultrasonic measurement has been used for ocean engineering, noninvasive medical application, and nondestructive testing for years. Ultrasound transducer plays a significant role in whole system. Ultrasonic transducer is piezoelectric transducer, it takes a wide range of relevant knowledge to fully describe it when conducting analyzes; therefore, there are many areas of domestic and foreign scholars, integrating a wide range of simulation methods, simulation software, or a combination of different algorithms to establish model that can represent the real system in order to reduce the costs of trial and error. In addition to the simulation, the actual manufacture and selection of acoustic material also deeply affect the merits of the finished design. However, the energy emitted from single ultrasound transducer is too small, so the array type of the ultrasound transducers is considered no matter in medical or engineering, hope that sound beam can achieve the best constructive interference in order to achieve the purpose of energy which is more concentrated. The research discuss different parameters which have impact on the sound field of linear phased array through simulation, the parameters including：element spacing, element width, element length, element numbers. The research fabricate ultrasound transducers to form a linear array, using a pairs of transducers to measure the directivity of it and figure out the directivity tendency of linear phased array. The results between experiment and simulation are compared to prove the feasibility of the study. Besides, the design of the linear phased array transducers is explored in this research. Hope to provide some reference for future work.

並列關鍵字

piezoelectric ultrasonic transducer ； linear array ； directivity ； sound field

參考文獻

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國際替代計量

相位式線陣列超音波換能器幾何參數對聲場之影響

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