MEMS Based Light Modulation for Lidar and Display Applications

Abstract

Resonant MEMS mirror has been recognized as one of the solid-state laser beam steering (LBS) solutions for AR display and lidar. Such MEMS resonant mirrors’ large angular throw achieves over tens of degrees in scanning field of view (FOV) with operation speed exceeding tens of kHz in resonant frequency. In LBS, beam area is critical especially for lidar to access targets located at a far distance. Having both a large angular throw and beam area or large Etendue, it is feasible to simultaneously satisfy requirement. For Time of Flight (ToF) lidar transmitter, we proposed and experimentally characterized a large Etendue LBS architecture employing a 2-dimensional MEMS mirror and diffractive LBS by Digital Micromirror Device (DMD). The fine scan of 2D resonant MEMS mirror device is multiplexed into five diffraction orders that the DMD produces to achieve m*n scan points, where n is the number of scan points produced from the resonant MEMS mirror and m is a diffraction orders supported by DMD.