GB1232405A - - Google Patents

Abstract

1,232,405. Electroluminescence. GERBER SCIENTIFIC INSTRUMENT CO. 29 Aug. 1968 [16 Feb., 1968], No. 41226/68. Heading C4S. [Also in Division H1] A display matrix (monochrome or colour) comprises an array of 4-layer semi-conductor switches, each of which may be rendered conductive by the application of pulses simultaneously to the two central layers thereof, and an array of light-emitting dots 30, each dot 30 being associated with and activated by a corresponding switch. The central layers of the switches are constituted by two mutually perpendicular superimposed sets of semiconductor strips 22, 24 respectively aligned with the rows and columns of the array of dots 30, so that any particular dot may be activated by the application of suitable pulses simultaneously to the appropriate strips 22, 24. The semi-conductor switch array may be formed as a series of epitaxial layers and the light-emitting dots 30 may comprise two layer diodes. One of the layers of each dot 30 may be constituted by the adjacent end of the corresponding switch. Insulating material is provided between the elements of the matrix. As shown, a transparent conductor 32 is provided below the light-emitting dots 30, and above each switch is provided a resistive dot 38 and a common conductor 40, each dot 38 serving as a current limiter for the corresponding switch and lightemitting device. The resistive dots 38 may be omitted or replaced by an array of dielectric dots, e.g. of barium titanate, providing a capacitance in series with each switch whereby the current through each switch will drop below the value required to sustain conduction a predetermined time interval after the switch has been rendered conductive. In a modified arrangement of this type, a conductive dot (68), Fig. 7 (not shown), is provided between each switch and the corresponding dielectric dot (74), the dots (68) being connected through resistive material (70) to a common conductor (72).