Design, fabrication, and characterization of out-of-plane W-form microsprings for vertical comb electrodes capacitive sensor

Abstract

The vertical comb electrodes capacitive sensor ͑VCECS͒ has been widely used in inertia sensors, resonant sensors, and pressure sensors, etc. In this paper, we present an improved microspring, called a W-form spring, that provides a large stiffness ratio in an out-of-plane direction while retaining a long sensing range for a VCECS. The stiffness ratio, defined as the ratio of the stiffness in the lateral direction to the out-of-plane direction, is an important parameter for determining the stability of the VCECS. To realize the properties of the W-form spring, such as the spring constant and stiffness ratio, theoretical analysis and numerical simulations are performed. In addition, VCECSs with W-form and other springs have been fabricated using microelectromechanical systems ͑MEMS͒ micromachining technology. The spring constants of the sensor have been calculated from simulations and measured results. The characteristics among different suspension springs are compared. According to the numerical simulations and experiment results, the working range and stability of the device are both improved for the VCECS by using the W-form suspension spring. © 2009 Society of Photo-Optical Instrumentation Engineers.

Geometric Effect on the Nonlinear Force-Displacement Relationship of Awl-Shaped Serpentine Microsprings for In-Plane Deformation

“…Therefore, the microsprings in MEMS devices have many applications. Microsprings can be used in MEMS actuators [1][2][3][4][5], MEMS sensors [6][7][8], in the micro-2D stage (micro-X-Y stage) [9][10][11][12], and for energy harvesting [13,14]. Improving the performance of microsprings is a key research topic.…”

“…Therefore, different types of microsprings [19][20][21][22] have been designed. The types of microsprings proposed in the literature are folded beam-type springs [21], double-clamped beam-type springs [23], crab-leg springs [24], serpentine springs [25,26], W-form springs [6], L-shape planar springs [27], and conical springs [28]. Among these types of microsprings, serpentine springs could be used in out-of-plane and in-plane motion.…”

Fabrication and analysis of awl-shaped serpentine microsprings for large out-of-plane displacement

“…To achieve a better performance, many researchers have intensively studied the different features of microsprings, such as stability [5], reliability [6], coupling [7], and in-plane or out-of-plane [8] motion for particular applications. Different types of microsprings, with their characteristics, have been proposed in the literature, as shown in table 1 [9][10][11][12][13][14][15][16]. Among them, serpentine springs are widely used in microdevices for their capabilities in larger deflection and appropriate layout area.…”