A diffractive multispectral image sensor with on- and off-die signal processing and on-die optics in 0.18 micron CMOS

摘要

On-die optics have been proposed for imaging, spectral analysis, and communications applications. These systems typically require extra process steps to fabricate on-die optics. Fabrication of diffractive optics using the metal layers in commercial CMOS processes circumvents this requirement, but produces optical elements with poor imaging behavior. This paper discusses the application of Wiener filtering to reconstruction of images suffering from blurring and chromatic aberration, and to identification of the position and wavelength of point sources. Adaptation of this approach to analog and digital FIR implementations are discussed, and the design of a multispectral imaging sensor using analog FIR filtering is presented. Simulations indicate that off-die postprocessing can determine point source wavelength to within 5% and position to within ±0.05 radian, and resolve features 0.4 radian in size in images illuminated by white light. The analog hardware implementation is simulated to resolve features 0.4 radian in size illuminated by monochromatic light, and 0.7 radian with white light.