Hughes Aircraft Company

Alex M Leupp

Hans G Dill

Henry T Peterson

Denis J McGreivy

Lewis T Lipton

A liquid crystal display addressable by a backplate semiconductor MOSFET switching matrix is made light insensitive by ion implanting the backplate around the MOSFETs to prevent the formation of photon generated inversion layers and by extending the reflective back electrodes over the MOSFETs to prevent incident light from striking those areas of the backplate which are not protected by ion implantation.

Light-insensitive matrix addressed liquid crystal display system

Substantial advantages over existing integrated transistorized matrices for driving flat panel liquid crystal displays may be achieved by the use of silicon on sapphire (SOS) and related technologies. Among the advantages are good isolation to prevent cross talk between circuit elements, simplified processing, reduced pinhole sensitivity, the possibility of utilizing the display in a back-lighted, transmissive mode of operation, and a greatly reduced sensitivity to ambient light. In the preferred embodiment disclosed, an integrated storage capacitor is associated with each transistor in the array. One plate of this capacitor, as well as the transistor and a plurality of vertical drain buses for the carrying of video signals may all be formed in a single processing step. In another single processing step it is possible to form the second plates of the capacitors, the gate electrodes and a plurality of horizontal gate buses upon which control signals may be impressed for line at a time addressing. Also in the preferred embodiment each bottom capacitor plate of a given vertical array is electrically shorted one to another thereby reducing the number of external ground connections required.

Method of making integrated transistor matrix for flat panel liquid

In forming the back panel of a liquid crystal display, layers of an insulating material and aluminum are successively deposited on the surface of a semiconducting substrate having an array of electrodes thereon. Openings are then formed through the insulating material and the aluminum layer to expose the electrodes, thereby defining a spacer lattice which is integral with the substrate and whose walls are of a uniform height which corresponds to the desired spacing between the front and back panels of the liquid crystal display.

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Costa Mesa, CA, United States of America

Alex M Leupp