Development of a MEMS digital accelerometer (MDA) using a microscale liquid metal droplet in a microstructured photosensitive glass channel

This paper introduces the operational concept, fabrication and experimental validation of a microelectromechanical systems (MEMS) digital accelerometer (MDA) that consists of a microscale (∼350 nL) liquid metal droplet in a microstructured channel etched into photosensitive glass. The MDA exploits not only the liquid metal droplet's high surface tension, high density and electrical conductivity, but also the photosensitive glass's mechanical stability and capacity to be photo-etched anisotropically. Photo-etching is used to etch an anisotropic channel into the device. During the etching process, microstructures form uniformly on the glass channel surface; they minimize contact angle hysteresis and allow the liquid metal droplet to move easily on the glass surface. By integrating the liquid metal droplet as a proof-mass to measure an input acceleration inside the microstructured photosensitive glass channel, a simple yet effective digital accelerometer is realized.