Two-dimensional MEMS scanner for dual-axes confocal microscopy

In this paper, we present a novel 2-D microelectromechanical systems (MMS) scanner that enables dual-axes confocal microscopy. Dual-axes confocal microscopy provides high resolution and long working distance, while also being well suited for miniaturization and integration into endoscopes for in vivo imaging. The gimbaled MEMS scanner is fabricated on a double silicon-on-insulator (SOI) wafer (a silicon wafer. bonded on a SOI wafer) and is actuated by self-aligned vertical electrostatic combdrives. Maximum optical deflections of +/- 4.8 degrees and +/- 5.5 degrees are achieved in static mode for the outer and inner axes, respectively. Torsional resonant frequencies are at 500 Hz and 2.9 kHz for the outer and inner axes, respectively. The imaging capability of the HEMS scanner is successfully demonstrated in a breadboard setup. Reflectance images with a field of view of 344 mu m x 417 mu mare achieved at 8 frames/s. The transverse resolutions are 3.94 and 6.68 mu m for the horizontal and vertical dimensions, respectively.