Interline CCD image sensor with an anti blooming structure

THE APPLICATION OF AN overflow drain and barrier positioned beside the photosensitive area1 has made it possible to suppress blooming of CCD image sensors. However, this method was found to sacrifice photosensitivity and dynamic range. This paper will describe an interline CCD sensor where the vertical overflow drain is positioned under, rather than beside the photodiode. Thus the cell area can now be used effectively for photoelectron generation and storage, and increased photosensitivity and dynamic range can be maintained. Furthermore, this technique eliminates the blooming phenomenon.