Micro Cantilever-Based Flow Meter for High Airflow Velocity Measurement

• Main Authors: Yu-Hsiang Wang, 王禹翔
• Other Authors: Chia-Yen Lee
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/24560890219622203053

碩士 === 大葉大學 === 機電自動化研究所碩士班 === 94 === This paper exploits a bending-up cantilever caused by residual stress to manufacture a micro gas flow sensor. Micro sensors not only have a smaller physical size than their traditional counterparts, but also provide a greater measurement accuracy and a higher sensitivity. In this study, mems techniques are used to deposit a silicon nitride layer on a silicon wafer to create a piezoresistive structure. A platinum layer is deposited on the silicon nitride layer to form a resistor and the structure is then etched to form a freestanding micro-cantilever. It is found that the cantilever bends upward slightly as a result of the released residual stress induced in the beam during the fabrication process. When an airflow passes over the cantilever beam, a small deformation occurs. Variations in the airflow velocity can therefore be determined by measuring the change in resistance caused by the beam deflection using an LCR meter. e experimental data indicate that the proposed gas flow meter has a high sensitivity (0.0533 Ω/ms-1), a high measurement limit (44.47 ms-1) and a rapid response time.