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Associative FET Image Sensor Array

IP.com Disclosure Number: IPCOM000075101D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Jutzi, WW: AUTHOR

Abstract

This retina-like image sensor array of integrated bistable cells for optical pattern recognition each including a photosensitive field-effect transistor which is selectively set optically and in parallel. The cells representing the picture points are then electrically accessed in an associative search operation. With proper search pattern input into the mask and I/O register to investigate the cell states, the match pattern output of the selectors provides a transform of the optical input, thus performing a first step of pattern recognition already in the optical sensor terminal.

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Associative FET Image Sensor Array

This retina-like image sensor array of integrated bistable cells for optical pattern recognition each including a photosensitive field-effect transistor which is selectively set optically and in parallel. The cells representing the picture points are then electrically accessed in an associative search operation. With proper search pattern input into the mask and I/O register to investigate the cell states, the match pattern output of the selectors provides a transform of the optical input, thus performing a first step of pattern recognition already in the optical sensor terminal.

Each of the about 1000 cells per chip comprises a bistable pair of cross- coupled transistors, one of which is light-controlled. Two load resistors, four additional transistors for access, and two isolating diodes complete the cell. Space saving MESFET technology permits integration of these diodes into the Schottky drain contact of the respective output transistor. All MESFETs are of the normally off type.

Optical sensing is performed with a MESFET of GaAs. Light through a window acts on a semitransparent gate region of one of the transistors and changes its source-drain resistance from a high to a low value. The light sensitivity threshold can be influenced by the supply of voltage at the photo flip- flop load resistors and the size of the window.

The cells of the matrix are connected in column direction via a pair of digit lines D1 and D0 for write a...