Wide Dynamic Range CMOS Image Sensors for High Quality Digital Camera, Security, Automotive and Medical Applications

Abstract

Wide dynamic range (DR) CMOS image sensors featuring a lateral overflow integration capacitor in a pixel, which locates next to the floating diffusion and integrates the overflow photoelectrons from the fully depleted photodiode in the same integration term, have been developed. The DR has been extended to 100 dB in a single exposure by adding the minimum number of the circuit elements to the four transistors type CMOS image sensor, with a high sensitivity, a high S/N ratio and a superior moving image quality. The hyper DR extension over 200 dB, with the equivalent light intensity ranging from 10-2 1x to 108 1x has also been achieved by the combination of the voltage readout operations of the above mentioned lateral overflow integration in multiple exposures and the current readout operation of amplifying the photodiode current. The S/N ratio dominated by all the noise components including the photon shot noise exceeds 40 dB in any switching point from low light to bright light.