波動方式提升超音波換能器效能之研究

Research on improving Ultrasonic Transducer efficiency by wave propagation method

呂宗諺(Tsung-Yen Lu)

指導教授 ： 張所鋐

國立臺灣大學/工學院/機械工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02497

摘要

隨著科技的發展，傳統的電磁骨刀開始無法滿足在生醫方面之應用，而具有較低噪音量、較低疼痛感及較高舒適度等優勢的超音波骨刀漸漸在此領域展露頭角，但由於切割功率不彰，對部分較硬之骨質或法瑯質仍不具切削力。本研究的目的便是在提升超音波換能器的輸出位移量、以及輸出功率，以提高超音波骨刀切削能力。本研究著重在壓電換能器效能的提升，主要方式是使由壓電陶瓷環所發出的應力波能有效傳遞到切削端，增加骨刀刀頭位移量以及切削能力，提升方法包含(1)改善壓電環與壓電環間接合介面的不平整、(2)用膠合方式改善壓電環的機電耦合係數、以及(3)改善與提升能量往切削端的傳遞方式。
在改善表面粗糙度方面，本研究將壓電環與壓電環之間加入銀膠，由銀膠將表面的不平整填平，改變銀膠種類，找出適合參數將換能器的前端位移量提升，降低換能器作動時的溫度，我們發現塗布液狀銀漆能夠提升位移量36%，塗布加熱銀膠可以降低溫度10℃。在提升機電耦合係數方面，本研究將壓電陶瓷環間加入絕緣膠體，目的是透過適當的膠體種類與適當的膠體厚度，提升機電轉換效率，我們發現使用硬度高的絕緣AB膠厚度0.5 mm能提升機電耦合係數8%。在提升單方向波傳方面，若能在夾持點之前將能量波反射，能量波將不會被浪費在夾持固定換能器的邊界上，此提前反射的能量將有助於前端刀頭的振動，我們發現使用有網格狀的不鏽鋼網，確實能提升換能器前端刀頭的位移量60%與輸出功率115%，缺點是同時會造成壓電陶瓷環溫度上升，若是能有效降低溫度，那麼此反射器確實能對位移量有提升效果。

關鍵字

超音波換能器 ； 壓電材料 ； 表面粗糙度 ； 機電耦合係數 ； 反射器

並列摘要

With the advance of technology, piezoelectric transducer with the advantages of low noise, light pain, and well comfortable become more and more popular than electromagnetic motor-driven transducer. Due to low cutting, ultrasonic transducer does not have the advantages of cutting quantity for hard tissue. The purpose of this research is to promote tip displacement and power of ultrasonic transducer.this research is focused on promoting efficiency of piezoelectric transducer, and the main method is that wave propagation is excited by piezoelectric is able to transmit to cutting edge, improving efficiency methods is including (1) improving surface roughness between piezoelectric ceramic. (2) improve Dynamic Electro Mechanical Coupling Coefficient of piezoelectric ceramic by adhesive method, and (3) improving and promoting the transmission of energy to cutting edge.
In the way of improving surface roughness between piezoelectric ceramic, we fill silver adhesive between piezoelectric ceramic, and the roughness would be improved by silver adhesive. Then we change the kind of silver adhesive to find the best parameter to promote the displacement of transducer. We find out displacement could be promoted 36% by silver adhesive and the temperature could be reduce about 10℃ by using silver adhesive with heating. In the way of improve Dynamic Electro Mechanical Coupling Coefficient of piezoelectric ceramic by adhesive method, we fill isolation adhesive between piezoelectric ceramic, the purpose is that promoting Dynamic Electro Mechanical Coupling Coefficient of piezoelectric ceramic by proper sort and thickness of adhesive. We find out the EMCC could be promoted 8% by using of high hardness AB adhesive 0.5 mm. In the way of improving and promoting the transmission of energy to cutting edge, if we could reflect the energy before it pass through fixed plane, the energy would not be wasted at fixed plane. We find out the stainless steel mesh could improving the displacement of tip 60% and output power of cutting 115% exactly. But it has disadvantage of higher temperature of piezoelectric ceramic. If we could cool temperature effectively, the reflector is helpful to promote displacement of tip.

並列關鍵字

ultrasonic transducer ； piezoelectric material ； surface roughness ； EMCC ； reflector

參考文獻

[3] Li Zhanhui, Wu Yunxin and Long Zhili, “Effect of Contact Interface on Ultrasonic Characteristic of Wire Bond Transducer,” Advanced Materials Research Vols. 139-141 (2010) pp 2350-2353

[4] Li Zhanhui, Wu Yunxin and Long Zhili, “Effect of Contact Interface Pressure on Higher-Order Harmonic Wave and Bond Strength,” Advanced Materials Research Vols. 148-149 (2011) pp 36-39

[5] P. Harkness, A. Cardoni, J. Russell and M. Lucas, “Designing a Hollow Langevin Transducer for Ultrasonic Coring,” Applied Mechanics and Materials Vols. 24-25 (2010) pp 65-70

[6] A M Chaston, C Edwards, S L Evans and K M Holford“Shear wave ultrasonic coupling performance of different adhesives,” Insight - Non-Destructive Testing and Condition Monitoring, 50 (11) pp 633-636

[7] Yun-long Geng, Li-mei Xu, Yi Wang, “Optimization of a circular piezoelectric micro-mechanical ultrasonic transducer on electromechanical coupling coefficient,”2009 China Symposium on Frequency Control Technology (2009)