A 28 mega pixel large area full frame CCD with 2/spl times/2 on-chip RGB charge-binning for professional digital still imaging

Abstract

CCD imagers for professional digital still cameras (DSCs) require in general high resolution. However for some applications, high sensitivity and high speed are more important and can be exchanged for resolution. A concept is presented in which the resolution of the imager will be decreased in binning mode while the sensitivity and frame rates are increased. For color CCDs, the RGB Bayer color filter pattern should be preserved after charge binning without discarding charge. The first results of this new concept are presented. IntroductionA 28 Mega pixel CCD image sensor with a novel 2x2 onchip RGB charge-binning concept for the high-end digital still camera market is presented. Although the resolution of the imager will be decreased in charge binning mode, the advantages of the binning concept can be found in higher sensitivity (4x), better signal to noise ratio (2x) and increased frame rates (3-4x) for applications that are less demanding with respect to resolution. Examples are motion (sport) digital still images, low-light image capturing and auto-focus information gathering. On-chip charge binning is a common technique for monochrome CCDs [1]. However, for color CCDs it is required that the RGB Bayer color filter pattern is reconstructed after the charge binning, and preferably, this should be done without discarding any of the captured charge packets. The new binning concept presented here meets these requirements and the first evaluation results and the overall device performance are reported.