Magnetically-driven surface-micromachined mirrors for optical applications

A surface-micromachined plate-type actuator with two torsional support beams has been developed for optical applications. A silicon-nitride plate with an area of 1 x 1 mm(2) is electroplated with a soft magnetic material (permalloy) and can be activated by an external magnetic field. In order to deflect the mirror to a very large angle, the geometry of the beams has been optimized using numerical simulation and theoretical analysis. Experimental data showed that the micro mirror is robust enough to be rotated up to 180 degrees over 10,000 times without any damage. The mirror is demonstrated as a laser beam deflector in this study. The deflection angle of the mirror can be controlled by the rotation of a permanent magnet. Data showed that this mirror could be rotated up to 90 degrees with a maximum frequency of 20 Hz. Details including design, fabrication, analysis, as well as operation, have been presented. Results showed that the device could be used as a scanning mirror for future application.