Scheme of flash LiDAR employing glass aspherical microlens array with large field of illumination for autonomous vehicles

This study demonstrates a new scheme of flash LiDAR using a glass aspherical microlens array (MLA) to achieve a large field of illumination (FOI) for autonomous vehicles. A wider FOI of up to 100° was obtained. In contrast to a spherical MLA, the FOI is 38.9° which indicates that the proposed aspherical MLA is 2.6 times wider than the spherical MLA. The wider FOI achieved for the glass MLA is due to a novel laser drilling technique that produces conical micro-holes with a high aspect ratio (depth: diameter = 1.8:1), forming elliptical-like aspherical microlenses through wet etching. An FOI estimation model to provide theoretical basis for designing aspherical MLA with wider FOI is presented, which is in good agreement with experimental results. Furthermore, the optical efficiency of 90% for the FOI was calculated. In this study, we have proposed a unique laser drilling technique to produce glass aspherical MLA with wider FOI and higher optical efficiency for flash LiDAR use in autonomous vehicle applications.