Design and fabrication of a liquid MEMS sensor

Significance 

Recent technological advancement in the micromechanical systems field has led to the development of more efficient sensors with vast application in numerous areas including military and civil. Currently, solid structures are used as sensing elements in a majority of micromechanical sensors owing to their accuracy and dynamic characteristics. Unfortunately, the complexity of the related fabrication processes of the solid structures has resulted in a corresponding increase in the cost of the sensors thus prompting researchers to look for alternative solutions.

Recent studies have identified liquid droplet as a suitable alternative sensitive element owing to its high overload resilience and less complex fabrication process. However, regardless of such improvements, it is still difficult to fully explore liquid droplet inclinometer sensors which possess great potential applications. For instance, in a recently published literature, using liquid mercury droplets as sensing elements resulted in several challenges such as the need for complex optical equipment and limited fabrication processes that increasing the entire sensor costs, rendering the process unsuitable for fabricating efficient liquid micromechanical systems inclinometer sensors.

To this note, Han-yang Xu (PhD candidate), Professor Yu-long Zhao, Kai Zhang, and Zi-xi Wang at Xi’an Jiaotong University from State Key Laboratory for Manufacturing Systems Engineering in collaboration with Professor Kyle Jiang from the School of Mechanical Engineering at the University of Birmingham developed a liquid micromechanical systems inclinometer sensor based on the liquid droplet as the sensing element. In particular, they proposed a criterion for the design, fabrication, and characterization of the sensors which involved electrodes that functioned to reflect the liquid metal position to determine the tilt angle. Their work is currently published in the research journal, Sensors and Actuators A: Physical.

In brief, the sensor design entailed an array of electrodes and hydrophobic annular groove contained in a bottom substrate. The annular channel provided the path for movement of the liquid metal droplet with the help of gravity. The middle layer comprised of annular channels whose patterns and geometric sizes were designed based on the relationship between the output and input signals of the sensor. Eventually, the proposed fabrication process of the liquid micromechanical systems sensor was verified through the tilting experiments.

The authors observed that the newly developed sensor exhibited a significantly wide measuring angle of ±45o and a resolution of 3.6250. In addition, it was noted that the accuracy and measurement range of the sensors could be improved by increasing the electrodes number and the annular grooves widths. Furthermore, the fabrication process involved a few steps thus reducing the overall manufacturing costs as compared to its solid micromechanical systems gyroscopes counterparts.

In summary, the study by Han-yang Xu and colleagues demonstrated an efficient design, fabrication, and characterization of a liquid micromechanical systems sensor. In general, their work elucidated on the key improvements including the outstanding resilience against impact, enhanced accuracy and sensitivity which will advance their application in various field in measuring accelerations, angles displacements among others.

liquid MEMS inclinometer sensor - Advances in Engineering

liquid MEMS inclinometer sensor- Advances in Engineering 1

About the author

Hanyang Xu received the B.S. degree in Mechanical Design and Automation Engineering from the Huazhong University of Science and Technology, China, in 2014 and the M.S. degree in Mechanical Engineering from the Huazhong University of Science and Technology, China, in 2016. He is currently working toward the Ph.D. degree in the State Key Laboratory for Manufacturing Systems Engineering of Xi’an Jiaotong University, China. His current research topics are related to MEMS liquid sensors.

About the author

Kyle Jiang is a fellow of IET, fellow of HEA, and board member of HKSME. He was awarded PhD degree in mechanical engineering by King’s College London, and Doctor of Science by University of Birmingham.

Kyle Jiang is a professor in the School of Mechanical Engineering, University of Birmingham. He is the Director of Micro/Nanotechnology Research Centre at University of Birmingham. His research interest covers microengines, turbochargers, micro and nano fabrication and nanostructures for energy and biomedical applications. He is active in organising and participating European projects, EPSRC projects and Innovate UK projects.

He has over 230 publications in books, book chapters and research papers in peer reviewed journals and international conference proceedings, including Nature Communications, Journal of Power Sources, Optics Express, and Nanotechnology. He is the inventor of 11 patents and won a prize in 2017 China innovation prize in Diaoyutai State House.

Professor Jiang is a reviewer of grant applications for UK Research Councils and European countries. He was the General Chair of IEEE 12th International Conference on Nanotechnology (IEEENANO 2012), general Co-Chair of NSTSI11, Publicity Chair of IEEE NANO 2013, and chaired many conference sessions. He is an editorial member of several International Journals, and appointed as Birmingham City Ambassador.

About the author

Yulong Zhao received his B.S degree on precise electron and machinery in Beijing Institute of Technology in Beijing, China in 1991. Then, in 1999, he received his M.S. degree in Xi’an Shiyou University in Xi’an, China. In 2003, he received the Ph.D. degree on high temperature MEMS pressure sensor in Xi’an Jiaotong University, Xi’an, China. He is currently a professor of Xi’an Jiaotong University, Xi’an, China.

His main research fields include MEMS sensors, biosensors, precise instrument and micro/nano manufacturing technology, and he has published about 100 scientific articles including 60 SCI indexed papers and 30 EI indexed papers. He also owns 50 china patents.

Prof. Zhao is a Doctoral Advisor & the Vice Director of State Key Laboratory for Manufacturing Systems Engineering. The rewards that Prof. Zhao received include: National Nature Science Foundation for Distinguished Young Scholars, Chang Jiang Scholars Program, National Talents Project, National High-level Personnel of Special Support Program (Scientific and Technological Innovation Leader), Tengfei Scholars Program of Xi’an Jiaotong University, Program for New Century Excellent Talents in University.

Reference

Xu, H., Zhao, Y., Zhang, K., Wang, Z., & Jiang, K. (2019). A liquid MEMS inclinometer sensor with improved sensitivity. Sensors and Actuators A: Physical, 285, 369-377.

Go To Sensors and Actuators A: Physical

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