White–Red–Green–Blue Lateral Overflow Integration Capacitor Complementary Metal–Oxide–Semiconductor Image Sensor with Color-Independent Exposure and Widely-Spectral High Sensitivity

Abstract

A high sensitivity white–red–green–blue (WRGB) complementary metal–oxide–semiconductor (CMOS) image sensor is proposed with color-independent saturation exposure based on lateral overflow integration capacitor (LOFIC) architecture. In case of conventional WRGB image sensors, the W pixels saturate in lower illuminance than the other pixels due to the same saturation exposure of all pixels. This WRGB LOFIC CMOS image sensor solves this problem by optimizing the size of LOFICs for each pixel color according to its sensitivity. The white (W) pixels have about 2.3 times higher sensitivity than the green (G) pixels and have 102-dB dynamic range (DR). Moreover, W pixels without infrared (IR) cut filter have high sensitivity for luminance through visible light band to near IR wave band. This image sensor realize that good color reproductivity imaging for the visible waveband and high sensitivity imaging for a wide waveband by one image sensor.