Liquid crystal display matrix array employing ovonic threshold switching devices to isolate individual pixels

DETAILED DESCRIPTION The present invention discloses an active matrix liquid crystal display panel including: 1) a plurality of liquid crystal display elements distributed in a matrix of rows and columns; 2) means for supplying video signals and display element selection signals, including row and column conductors; and 3) a plurality of threshold switching elements each serially coupled between the corresponding row or column conductor and the liquid crystal display element, said threshold switching elements acting as display element selection devices and current isolation devices; said threshold switching elements having an off state resistance of at least 1.
times.
10.
sup.
9 ohms.
Preferably the off-state resistance of the threshold switches is greater than about 1.
times.
10.
sup.
10 ohms.
More preferably the off-state resistance is greater than about 1.
times.
10.
sup.
11 ohms.
Most preferably the off-state resistance is greater than about 1.
times.
10.
sup.
12 ohms.
The threshold switching materials of the present invention may be formed from As-Te based chalcogenides and they additionally include one or more elements such as Ge, Si, P and Se.
When needed, a resistive element may be added in series with the Ovonic threshold switch to insure the liquid crystal display element is properly charged before the current flowing through the threshold switch falls below the holding current thereof.