Angle Sensitive Pixels in CMOS for Lens less 3D Imaging

We present a pixel-scale CMOS sensor for near-field, lensless 3D imaging. This angle-sensitive pixel (ASP) uses local, stacked diffraction gratings over a photodiode to discriminate the incident angle of incoming light. The ASPs, measuring 20 mu m wide and 40 mu m long, have been built in an unmodified 130nm CMOS process. Metal wiring layers provide the required gratings, while intrinsic pn-junctions act as photodiodes. We present operating principles and design considerations of the ASP, as well as results demonstrating desired angle sensitivity. Arrays of ASPs enable lensless microscale imaging that reconstructs the 3-dimensional structure of light sources.