Illumination source identification using a CMOS optical microsystem

An integrated silicon color sensor system has been designed and fabricated in CMOS without extra masks for color filtering. The application is in low-cost measurement of ambient light conditions, e.g., for display control in portable instruments, or for testing the intensity and spectral distribution of light sources. Signals proportional to the intensity and the spectral distribution of the incident light are available at the output in the form of two bitstreams. It is demonstrated that daylight can be distinguished from other light sources, such as incandescent lamps and fluorescent lamps.