Study of a new spring structure for a mechanically reliable micromirror

This paper reports that the mechanical reliability of the micromirror can be improved by a new spring structure called interdigitated cantilevers without any help of mechanically reliable materials and any control of operation condition. The micromirror with interdigitated cantilevers was subjected to 2 times lower maximum Von Mises stress for cyclic rotations than a conventional micromirror with a hinge when two micromirrors have the same performance and the same rotation angle in analytical calculations and FEM simulations. The micromirror with interdigitated cantilevers made of a pure aluminum was operated successfully without any failure over an operation time of 500 hours and 2 × 10¹⁰ cycles at air condition (23°C and 45 %).