Hybrid grated pixel cluster for local light angle and intensity detection

Abstract

Detecting local light incident angle is a desirable feature for CMOS image sensors for 3D image reconstruction purpose. Advances in the CMOS technologies in the lasts years have enabled integrated solutions to perform such a job. However, it is still not viable to implement such a feature in regular CMOS image sensors due to the great number of pixels necessary in a cluster to perform incident angle detection. In this paper, it is proposed a hybrid cluster with only four pixels, instead of eight pixels of previous solutions, that is able to detect both local light intensity and incident angle. The technique to detect local incident angle is widely exploited in the literature. Two novelties are explored in this work, the first is the new paradigm in polarization pixel-cluster design, and the second is extend ability of metal-shielded pixels to detect both local light angle and intensity. Experimental results show a dynamic range difference of less than 2.5 dB between a pixel with 40 % of metal shielding and a pixel no metal shielding.