Hybrid assembled MEMS scanner array with large aperture for fast scanning LIDAR systems

Abstract

Abstract This article presents a large aperture micro scanning mirror (MSM) array especially developed for the panoramic 3D-ToF camera Fovea-3D. The Fovea-3D system uses a fiber amplified pulsed laser ToF technique at λ = 1550 nm \lambda =1550\hspace{0.1667em}\text{nm} with 1 MVoxel distance measuring rate. It targets for real time 3D imaging with a panoramic optical field of view (FOV) of 360 ° × 60 ° 360^\circ \times 60^\circ (horizontal × vertical) combined with a large distance measurement range of 100 m and a video-like frame rate of 10 Hz. For fast vertical scan axis a MEMS scanner module with large receiver aperture was especially developed. It increases the scanning rate to 3200 Hz which is four times faster in comparison to state-of-the-art fast macroscopic polygon scanning systems used for LIDAR systems. To guarantee at the same time a large reception aperture of D eff = 23 mm {D_{\mathit{eff}}}=23\hspace{0.1667em}\text{mm} , large FOV of 60 ° 60^\circ and high vertical scanning rate of 3200 Hz, a hybrid assembled MSM array was developed consisting of 22 reception mirrors and a separate emitting mirror for laser scanning of the target. For Fovea3D hybrid assembly of frequency selected scanner elements was chosen instead of a monolithic MEMS scanner array to guaranty a high yield of MEMS fabrication. All MSM are driven in parametric resonance to enable a fully synchronized operation of all individual MEMS scanner elements. Therefore, piezo-resistive position sensors are integrated on each MEMS chip for position feedback of driving control. The paper discusses details of the MEMS system integration including the synchronized operation of multiple MEMS scanning elements.