Patent ID: 6180935
Filing Date: 2001-01-30
Classification: H01L,H04N

Abstract:
A method of achieving dynamic range extension (DRE) in a CCD imager exposed to combined low and high intensity illumination, said imager having a CCD imaging surface for converting incident illumination into electrical charge, and gate electrodes acting on said surface having a voltage V.sub.G applied thereto to form pixel signal charge wells at well sites below said surface during charge integration, comprising the steps of:imposing a voltage V.sub.G -LOW on said gate electrodes at the pixel signal charge integration well sites, said voltage V.sub.G -LOW being of a level that results in signal charge wells above the reference signal level for automatic light control used in CCD imager systems and of a time duration equal to a large percentage of the total time of charge integration; andthen imposing a voltage V.sub.G -HIGH on said gate electrodes at the pixel signal charge integration well sites, said voltage V.sub.G -HIGH being of a level that is above the level of voltage V.sub.G -LOW and of a comparatively short time duration with respect to the total time of charge integration.