GB1169718A - Electroluminescent Device - Google Patents

Abstract

1,169,718. Electroluminescence. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. 24 Oct., 1966 [25 Oct., 1965; 8 June, 1966], No. 47646/66. Heading C4S. An electroluminescent device comprises glass base 1, electroluminescent layer 4, electrode pairs 2<SP>1</SP>, 2<SP>11</SP>, non-linear impedance layer 5 (e.g. a non-linear ferroelectric capacitance layer), A.C. source 3 for applying an A.C. field across layer 4 by means of the A.C. flow in the non-linear impedance layer in the lateral direction thereof, and means, including for instance opaque resistance layer 6, photo-conductive elements 7 with electrode pairs 8<SP>1</SP>, 8<SP>11</SP> and D.C. source 9, for applying a D.C. field to non-linear impedance layer 5 to control its impedance in the lateral direction thereof. In Fig. 3 (not shown), resistance layer 6 is excluded and a non-linear resistance layer (10) in the form of a semiconducting thin film (eg, a SiC varistor or CdS) replaces the ferro-electric layer and a positive rather than negative image is produced. In Fig. 1 (not shown), photo-conductive elements 7 and electrodes 8<SP>1</SP>, 8<SP>11</SP> are single layers. The phosphors may be ZnS: Cu, Al in a binder; the photo-conductive layers CdS: Cu, Cl in a binder of high specific resistance such as epoxy resin; the ferro-electrics may be BaTiO 3 or (Pb, Zn) TiO 3 ceramics, electrodes 2<SP>1</SP>, 2<SP>11</SP> of stannic oxide and electrodes 8<SP>1</SP>, 8<SP>11</SP> of Al, conductive paint or stannic oxide. Phosphor layer 4 may be 30 microns thick; thicknesses of the other layers and electrode widths and separations are also disclosed.