A CMOS image sensor obtains color through the use of two or three superposed layers. Each pixel in the image sensor includes a plurality of superposed photosensitive p-n junctions with individual charge integration regions. The combination of each of the superposed layers provides increased sensitivity...http://www.google.ca/patents/US6870149?utm_source=gb-gplus-sharePatent US6870149 - Superposed multi-junction color APS
