Miniaturization of Compensational Spring System using the Highly Nonlinear Curved beams in MEMS

In this work an approach to minimize a non-linear system with a flat region in the force-displacement characteristics is studied. Design, simulation, fabrication and characterization of the initial system with the linear compensational spring and that of a miniaturized one without it are presented. The presented highly nonlinear curved beam system shows the same behavior as that with compensational spring system in terms of force-displacement both in the finite element simulation and in the experiment. Thus, an equivalent miniaturized system is proposed with the surface footprint reduced by 2.38 times only by designing means, without changing the technological steps. 1. Introduction The problematics of miniaturization of separate mechanical elements in micro-electro-mechanical systems (MEMS) remains actual [1]. There are two main techniques that are can be referred in miniaturization of the MEMS devices: either the straightforward decrease in the size of elementary components [2] (which is limited by the available technology of fabrication and design rules, mainly related to anisotropic etching), or by the design of alternative structural elements shapes [3] (general design methodology is not defined in this approach). Springs, as a structural element in MEMS, are considered to be of crucial importance, as far as they are used in an extremely wide variety of devices [4,5]. Typically, non-linear springs are widely used in a variety of energy harvesting applications [6], resonators [7], switches and actuators [8]. In our research, a need for miniaturized nonlinear springs with a flat force-displacement region has arisen. In the present work, a design, simulation, fabrication and experimental verification of a miniaturized spring is presented in comparison to the original non-miniaturized system.