Twin-Channel (P and N) CCD Image Sensor with Cross Anti-Blooming

A new class of Frame-Transfer CCD image sensors is presented which uses both electrons and holes as information carriers and has a novel cross anti-blooming structure for overexposure protection. The device consists of alternate columns of p- and n-channel CCD's shown in Fig. 1 which forms two separately operating pand n-type imagers. This concept uses the n channel as a channel isolator for the p-channel and vice versa, and has these advantages: (1) The complete area of the image section is active because no light-insensitive channel-stop area is required; (2) Both photon generated carriers - electrons and holes - can be stored and transported, thus doubling the useful information; (3) In a typical four-phase clocking system as shown in Fig. 1, the electron pixels and the hole pixels are separated by half a pixel pitch in both the vertical and horizontal directions, thereby improving the pixel-packing density, aliasing, and Moire suppression; (4) The pattern also forms a line-quincunx sampling grid, which offers many advantages for signal processing, especially when the pand n-output signals are simultaneously available; (5) This pixel configuration is also ideally suited for realizing a progressive-scan imager.