Multi-element self-scanned mosaic sensors

Mosaic sensors incorporating thin-film and silicon techniques are being investigated. An experimental solid-state television camera incorporating a 256 × 256 element photoconductive array, scanned by integrated thin-film decoders, has been built. The array comprises 65,536 photoconductor-diode elements, connected to perpendicular address-strips spaced upon 2.08 mil centers. Vertical scanning is accomplished by means of a 256-output diode decoder deposited by thin-film teehniques on the same substrate with the array. Horizontal scanning circuits, including a transistor decoder, videocoupling transistors, and capacitors are deposited on a second glass substrate, which is joined to the first and interconnected by thin-film techniques. The two substrates are attached to a printed-circuit card for convenient plugging into the camera. The entire array is scanned in 1/60 second at a clock rate of 4.8 MHz, permitting the picture to be displayed on a standard television monitor. Operating sensitivity was increased by the use of a high-gain photoconductor, in combination with charge-storage for a line-period. Silicon photodiode arrays of novel construction, permitting close spacing between elements, have been scanned with thin-film addressing circuits. The relative merits of silicon-vs.-thin-film techniques for image-sensors will be discussed.