Zhang Ye, Rajamani Rajesh, Sezen Serdar
Department of Mechanical Engineering, University of Minnesota at Twin Cities, Minneapolis, Minnesota, 55455, USA.
St. Cloud State University, St. Cloud, MN 56301, USA.
IEEE Sens Lett. 2017 Dec;1(6). doi: 10.1109/LSENS.2017.2766198. Epub 2017 Oct 24.
Traditional capacitive sensors suffer from significant parasitic noise when used in liquid environments or inside the human body. The parasitic noise overwhelms the force response of the sensor and makes it impossible to calculate the absolute force experienced by the sensor. This article focuses on the development of a supercapacitor based force sensor that is immune to parasitic noise. The supercapacitor consists of co-planar electrodes and a solid state ionic gel electrolyte on a deformable membrane. Force exertion causes deformation of the electrolyte membrane, increases its area of contact with the electrodes, resulting in a change of capacitance. The sensor is sealed, waterproof, and shows absolutely no changes in capacitance when immersed in water or enclosed in extracted sheep tissue. At the same time, its force sensitivity of 0.13 F/N exceeds the 0.3 pF/N sensitivity of a traditional capacitive sensor by 6 orders of magnitude. The developed sensor could have many biomedical applications in which parasitic capacitance is a serious challenge.
传统电容式传感器在液体环境或人体内部使用时会受到严重的寄生噪声影响。寄生噪声会掩盖传感器的力响应，使得无法计算传感器所经历的绝对力。本文重点介绍一种基于超级电容器的力传感器的开发，该传感器不受寄生噪声影响。超级电容器由位于可变形膜上的共面电极和固态离子凝胶电解质组成。施加力会导致电解质膜变形，增加其与电极的接触面积，从而导致电容变化。该传感器是密封防水的，浸入水中或包裹在取出的羊组织中时，电容绝对不会发生变化。同时，其0.13 F/N的力灵敏度比传统电容式传感器的0.3 pF/N灵敏度高出6个数量级。所开发的传感器在寄生电容是严重挑战的许多生物医学应用中可能会有应用。
