7.4 A 256×128 3D-Stacked (45nm) SPAD FLASH LiDAR with 7-Level Coincidence Detection and Progressive Gating for 100m Range and 10klux Background Light

Abstract

3D vision is an increasingly important feature in many applications of consumer, automotive, industrial, and medical imaging. Long range, high depth resolution, high spatial resolution, and high frame rates, are often conflicting requirements and difficult to be simultaneously achieved, especially in extreme ambient light conditions. In order to address range and depth resolution, direct time-of-flight has emerged as a powerful technique to perform light detection and ranging (LiDAR), thanks to advances in low-jitter optical detectors, such as single-photon avalanche diodes (SPADs), and accurate time-to-digital converters (TDCs) [1]–[5]. High spatial resolution can be achieved using scanning, at a cost of system complexity and somewhat lower frame rates [1], [3], while FLASH sensors [2], 4, [5] offer an alternative for both high frame rates and large pixel counts, but at limited ambient light conditions, due to typically long exposure times.