A Day and Night Vision MOS Imager With Robust Photonic-Crystal-Based RGB-and-IR

This paper demonstrates a day and night vision MOS imager with red, green, blue (RGB) and extra near-infrared filters placed over individual pixels. The on-chip RGB and IR filters are fabricated from an inorganic photonic crystal color filter (PCCF) technology, thereby realizing a robust and reliable camera module for indoor and outdoor use without mounting a mechanical IR-cut filter. These PCCFs allow the IR band as well as the RGB bands to pass through to the RGB photodiodes from which RGB signals, each involving some amount of IR component, are derived. During the daytime, however, chromatically almost pure RGB colors are reproduced by subtracting a weighed IR signal of an extra IR pixel from the raw RGB signals of the surrounding IR pixels. As a result, the IR components in the resultant RGB signals are minimized from 25%, 21%, and 50% to 9%, 4%, and 21%, respectively. During the night, on the other hand, an IR image having a resolution match with a conventional IR imager can be captured by using the IR components of the raw RGB signals with the IR signal.