Image sensors based on charge transfer by integrated bucket-brigades

Image sensors which are internally scanned by bucket-brigade or charge-coupling offer the opportunity fcr improved signal-to-noise ratio and ease of fabrication over conventional x-y addressed sensors. A completely-integrated self-scanned bucket-brigade sensor having 32 × 44 elements spaced on 3 mil centers has been built. As few as nine leads are required for scanning and signal output, High signal-to-noise ratio and reduction of spurious switching transients are possible by the transfer of all elemental charges to a single output terminal whose capacitance is no more than that of each elemental capacitor. A 32-stage bucket-brigade shift register is used as a vertical scanner for gating the horizontal clock drives to successive lines. Operating characteristics will be described and compared with published data on x-y addressed and charge-coupled sensors.