A novel Bayer-like WRGB color filter array for CMOS image sensors

We have developed a CMOS image sensor with a novel color filter array(CFA) where one of the green pixels of the Bayer pattern was replaced with a white pixel. A transparent layer has been fabricated on the white pixel instead of a color filter to realize over 95% transmission for visible light with wavelengths of 400-700 nm. Pixel pitch of the device was 3.3 um and the number of pixels was 2 million (1600H x 1200V). The novel Bayer-like WRGB (White-Red-Green-Blue) CFA realized higher signal-to-noise ratios of interpolated R, G, and B values in low illumination (3lux) by 6dB, 1dB, and 6dB, respectively, compared with those of the Bayer pattern, with the low-noise pre-digital signal process. Furthermore, there was no degradation of either resolution or color representation for the interpolated image. This new CFA has a great potential to significantly increase the sensitivity of CMOS/CCD image sensors with digital signal processing technology.