A Thermo-Pneumatically Actuated Tip-Tilt-Piston Mirror

We present a novel, high stroke tip-tilt-piston micro-mirror actuated by thermo-pneumatic forces. A circular silicon mirror plate is mounted on top of three balloons, made of a 50 μm thick elastomer membrane. The balloons are inflated under thermo-pneumatic pressure, thus driving the mirror plate into tip-tilt and piston motion. Very large stroke values of 385 μm as well as tip-tilt angles of 5° were measured. The triangular arrangement of the balloon actuator yields a high flexibility in mirror motion, including tip-tilt in any direction.