Programmable active pixel sensor for low-light biomedical applications

Abstract

Today, the diseases are being treated with less invasive and more sophisticated, technology-oriented methods. The diagnostic tools that were usually used in the hospitals have become available at our homes. Within the heart of this new generation health-care systems, CMOS technology lies with its high capability of integration, low power consumption, and low cost. Within this context, CMOS image sensors require continuous research effort in this field. In this paper, we introduces a novel programmable Active Pixel Sensor (APS), which gives the end-users to choose among different modes of sensor operation by varying the pixel pitch/size vs the sensor output resolution. This method increases the photon collection efficiency and maximum two times the Signal to Noise Ratio (SNR). The final camera chip reaches a very high fill-factor of 79% with a total pixel size of four pixel as 12.64μm × 12.64μm, while the size of each photodiode is 5.6μm × 5.6μm. The full-well capacity and conversion gain are respectively 66629e- and 27μV/e-, while the total chip area is 5 × 5mm2.