Integrated CMOS Optical Sensor for Light Spectral Analysis

In this paper, a fully integrated photo sensor in standard CMOS technology is reported, which enables light spectral analysis in the visible light range without additional optical components like color filters or gratings. The proposed sensor structure provides a continuously tunable spectral responsivity based on lateral carrier diffusion effects in combination with tunable field electrodes for defined carrier redirection. The tunable responsivity characteristics in combination with digital signal processing can be deployed for light spectral analysis like color measurements or full light spectral reconstruction. The realization of an accurate photometric color measurement based on the CIE X, Y, Z or R, G, B standard will be presented as an example for a basic light spectral analysis. Furthermore, the sensor application in a basic spectrophotometer is presented, providing a unique opportunity to realize a highly integrated low-cost spectrophotometer for basic spectral light measurements using a low-cost standard CMOS technology without process modification.