Vacuum operation characteristics of two-dimensional micro-mirror

We present design, fabrication and characteristics of two-dimensional micro-machined scanner. The resonant frequencies of horizontal and vertical axes are 40 kHz and 162 Hz for the inner mirror and gimbal frame, respectively. The optical scanning angles are obtained to be 11.5 and 14 degrees at the low driving voltages of 12 and 10 V in 1 Pa vacuum for the horizontal inner mirror and vertical gimbal frame, respectively. The scanner can be actuated simultaneously and independently in the two orthogonal axes using a slanted electrostatic comb-drive and silicon conductive V-shaped torsion hinges. The dependence of quality factor on pressure for the inner mirror and gimbal frame was also experimentally investigated and compared with the theoretical calculation based on air-friction models.