超音波換能器頻率校正電路設計

Design and Implementation of an Ultrasonic Transducer Frequency Calibration Circuit

黃翔偉(Hsiang-Wei Hwang)

指導教授 ： 陳秋麟 教授

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.10703

摘要

壓電換能器是目前最廣泛應用於力學與電學之間轉換的媒介。藉由壓電原理將電學的振盪轉換為力學的振動並發射超音波為目前產生超音波的主要方法。以壓電式超音波換能器進行發射或是接收等等的技術也廣泛應用在生活的各個領域中，例如：汽車倒車雷達、超音波淨水、超音波物理治療以及超音波影像等等。然而壓電材料的特性會隨著環境或是製程飄移等等因素而有所改變，使得其最佳的操作頻率也會隨之改變。因此在本論文中，將對壓電式超音波換能器的運作原理及其發射的方式作詳細的探討，並將提出一個方法解決操作頻率的尋找和校正的問題。最後，實作該電路並以超音波換能器的阻抗來作對應及驗證。

關鍵字

超音波換能器 ； 頻率校正 ； 最佳操作頻率 ； 校正電路

並列摘要

Piezoelectric material is the most widely used component to transform between mechanical energy and electrical energy. One of the piezoelectric applications is the ultrasonic transducer. The method to transmit ultrasound is driving an ultrasonic transducer by electrical signal at the frequency higher than 20kHz and the ultrasonic transducer will vibrate at the frequency and transmit ultrasound to the air or the other medium. Also, it can be used as an ultrasound receiver. The technique is widely used in our life such as vehicle backing radar, water cleaning system, medical imaging. However, the characteristics of piezoelectric materials will change with the environment, the process deviation, the damage of the material and so on. Thus, the proper operation frequency for an ultrasonic transducer will be different from time to time and from the other transducers. In this thesis, piezoelectricity effect and the operation of the ultrasonic transducer is investigated in detail. Besides, a circuit to trace the proper operating frequency for an ultrasonic transducer is proposed in this thesis. Finally, the calibration circuit is implemented and verified by theoretical calculation and comparison to the impedance of the ultrasonic transducer.

並列關鍵字

Ultrasonic Transducer ； Frequency Calibration ； Optimum Operating Frequency ； Calibration Circuit

參考文獻

[1] P. Curie, and J. Curie, “Bull.Soc.Min de France,” 3, pp. 90, 1880.

[2] 吳朗, “電子陶瓷：壓電陶瓷,” 全欣資訊圖書股份有限公司,1994.

[3] Tokin America Corp., Multilayer Piezoelectric Actuators: User’s Manual, San Jose, California, 1987.

[4] Murata Manufacturing Co. Ltd., Ultrasonic Sensor, Available: http://www.murata.com/products/catalog/pdf/s15e.pdf

[5] Antonio Arnau Vives, “Fundamentals of piezoelectricity,” in Piezoelectric Transducers and Applications, 2nd edition, Springer, 2008.