新型熱挫曲式出平面致動器

A Single-layer Step-bridge for Out-of-plane Thermal Actuator

葉柏毅(Po-I Yeh)

指導教授 ： 方維倫

國立清華大學/工學院/動力機械工程學系/碩士(2006年)

摘要

本研究設計並製作一單層薄膜出平面之熱致動器，可解決傳統雙層薄膜出平面熱致動器會有材料脫層及可靠度之問題。其致動原理，採用熱挫曲的方式使出平面致動器之位移量增加。致動器之結構由一微橋式樑結合中央兩階梯結構所構成，藉由此階梯結構之設計可控制挫曲之方向、降低挫曲條件、使挫曲平順和控制動態響應特性等特點。
另外，可透過力學的原理，調整結構之幾何尺寸，達到調變彎曲及挫曲兩種機械力學行為互相耦合的比例，進而產生不同的位移輸出。而在動態特性上，在約46Hz的低頻操作時，有一個因為熱行為所產生的低頻輸出峰值，此外，在結構本身的共振頻率86.5 kHz的操作頻率下，亦有一個高頻輸出峰值，由此研究成果可發現，熱致動器除了適用於一般熟知的低頻操作外，亦可操作於結構共振之高頻範圍。另外，更可利用階梯結構之設計，控制頻率響應上偶數或奇數模態的消失，以充分掌握致動器的動態特性。最後，將本致動器應用在微掃描面鏡與定位平台之上，且可得到不錯的特性輸出。

關鍵字

熱致動器 ； 挫曲 ； 出平面致動器 ； 微機電系統

並列摘要

This study presents the design and fabrication of a single layer step-bridge out-of-plane actuator. It can solve the delamination problem of traditional bi-morph electrothemal actuators. The step-bridge actuator consists of a clamped-clamped beam with two step-structures. Thus, the actuator will be bent as well as buckled in the out-of-plane direction by Joule heating. Moreover, the moving direction of the actuator is determined by the step-structure.
The output displacement can be changed by varying the length d for a given beam length L. It demonstrates that the actuator moved upward with amplitude near 13.2 um when driven at 54 mW. The characteristic of the dynamic response has two peaks at 46 Hz and 86.5 kHz. The first peak is due to thermal behavior and the second peak is resulted from resonance of the structure. Furthermore, by using the design of the step-structure can control disappearance of even or odd structure mode, which can be apply to more applications. Finally, we utilized the actuator in micro scanner and micro position stage applications.

並列關鍵字

thermal actuator ； buckle ； out-of-plane actuator ； MEMS

參考文獻

[1]W. Riethmuller, and W. Benecke, “Thermal excited silicon microactuators,” IEEE Transactions on Electron Devices, 35, pp758-763, 1988.

[2]W. Benecke, and W. Riethmuller, “Applications of silicon-microactuators based on bimorph structures,” Proceedings of the IEEE MEMS’89 Workshop, Salt Lake City, UT, February 1989, pp.116-120.

[3]B. Rashidian, and M. G. Allen, “Electrothermal microactuators based on dielectric loss heating,” Proceedings of the IEEE MEMS’93 Workshop, Ft. Lauderdal, Fla. February, 1993, pp. 24-29.

[4]J. W. Suh, C. W. Stroment, and G. T. A. Kovacs, “Characterization of multi-segment organic thermal actuators,” The 8th Int. Conf. Solid-State Sensors and Actuators, and Eurosensors Ⅸ（Transducer ’95, Eurosensors Ⅸ）, Stockholm, Sweden, Junuary, 1995, pp. 333-336.

[5]J. M. Noworolski, E. H. Klaassen, J. R. Logan, K. E. Petersen, E. Kurt, and N. I. Maluf, “Process for in-plane and out-of plane single-crystal-silicon thermal microactuators,” Sensors and Actuators A, 55, pp. 65-69, 1996