Micro-mirror laser scanner combined with a varifocal mirror

A laser beam scanning system consisting of a scanning micro-mirror and a varifocal micro-mirror is fabricated for laser beam sensing with variable beam diameter. The scanning micro-mirror is operated under the resonant oscillation condition with an electrostatic comb-drive actuator. The varifocal micro-mirror is driven by a bending moment generated at the circumference of mirror with a parallel-palate electrostatic actuator. The scanning micro-mirror and the varifocal mirror are fabricated on a silicon on insulator wafer. The rotational angle of 9° at 766 Hz is obtained at the voltage of 300 V. The spot size of the laser beam is adjusted from 0.5 to 3.5 cm at the distance of 43 m by changing varifocal voltage. The proposed scanning system can be useful for several sensing techniques.