Design and Realization of a Lensless CMOS Image Sensor for Light Source Tracking
Secil Sanseven (TU Delft - Electrical Engineering, Mathematics and Computer Science)
Sten Vollebregt – Mentor (TU Delft - Electronic Components, Technology and Materials)
Joost Romijn – Mentor (TU Delft - Electronic Components, Technology and Materials)
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Abstract
Localization of a light source in the space requires capturing its light intensity and angle information. However, conventional CMOS image sensors can only capture light intensity and wavelength. These sensors need to be augmented with an optical extension such as an aperture or a lens in order to capture the angle information. The use of optical apertures presents various drawbacks regarding the need for calibration, the difficulty of miniaturization, and CMOS integration. This work presents a lensless CMOS image sensor architecture for light source tracking applications, thereby eliminating the need for an optical aperture for angle sensitivity. The proposed design of angle-sensitive pixels (ASPs) with 1 um, 1.5 um, and 2 um grating pitches are implemented on a 5.6x5.6 um2 photodiode array. The fabricated ASP device with 2 um grating pitch can resolve angles up to 0.37∘ accuracy with post-process characterization. Furthermore, a metal shading structure is incorporated into the pixel array for coarse angle detection which determines the incident angle’s location on the periodic ASP response.