A novel quasi-static MEMS piezoelectric micromirror array with a high fill factor and three degrees of freedom

This paper presents the design of a novel 3x3 piezoelectric micromirror array (PMMA) with an 84.6 % fill factor and describes a three-dimensional hidden fabrication platform. The fabricated device operates with quasi-static mode in 3-degree-of-freedom, namely tip, tilt, and piston. In order to achieve a high fill factor, a threedimensional hidden micromirror array structure is introduced, and is realized through multi-layer bonding. In addition, a double-stop-layer's glass cover for optical device was employed to realize transparent wafer-level packaging. The device testing result achieves a mechanical tilting angle of 4.4 mrad at 82.5 VDC with over 99.5 % linearity. This design has the potential to achieve a larger size of micromirror arrays.