A scanning micromirror with stationary rotation axis and dual reflective surfaces for 360° forward-view endoscopic imaging

We report a novel dual-reflective MEMS mirror for full-circumferential-scanning (FCS) (360deg), forward-view endoscopic imaging applications. A unique electrothermal dual-folded-bimorph (DFB) actuator that can generate large rotation angles with a stationary rotation axis is employed. The fabricated devices demonstrate over 90deg mechanical rotation angles at frequencies up to 60 Hz with driving voltages of less than 12 V. A fast response with a cut-off frequency above the device's mechanical resonance of 447 Hz has been achieved. FCS patterns have been experimentally obtained by combining both the mirror surfaces. The measured radius curvature and surface roughness of the mirror are about 0.65 m and 30 nm, respectively.