Abstract
The electrostatically driven scanning micro mirrors are fabricated for the application to laser display. Electrostatic drives using comb electrodes are simple in structure and easily fabricated by conventional MEMS processes as well as inherent low loss. However, a high voltage is needed for the operation. In this paper, in order to operate mirror at a high frequency, a low voltage and with a large rotation angle, we investigate the operation characteristics of micro mirror with vertically driven comb in vacuum. The fabricated micro mirrors have torsional resonant frequencies between 9 kHz and 25 kHz. The optical-scanning angle is in the range from 0.37 to 3.75 degrees in air with ac actuation voltage of 60V. Due to the operation in vacuum, the rotation angle increases by 52 times larger than that in atmospheric air at the same operation voltage, which corresponds the decrease of operation voltage by a factor more than 7 for the micro mirror having 24.5 kHz resonant frequency. The quality factor depending on air damping is also investigated in pressure range from 100 Pa to 10^<-1> Pa.
