Liquid crystal display matrix - with automatic blanking for non-addressed cross points

摘要

The matrix is a liquid crystal cell with conventional parallel sets of strip elements on opposite faces and at right angles. Column electrodes are connected via switches to a reference potential and row electrodes via further switches to the excitation supply voltage so that when one switch of each set is closed, the relevant cross point is addressed and energized using esp. d.c. or low frequency a.c. exciation. Also applied to the row electrodes via coupling capacitors is an a.c. voltage at a frequency above that which excites the crystal material into optical change and this provides automatic blanking of nonselected cross points to improve resolution by preventing shunt excitation.