Title:
ELECTROLUMINESCENT DEVICE FOR DERIVING A BRIGHT OUTPUT IMAGE FROM A DARK INPUT IMAGE
United States Patent 3465202


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 21, 211, 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 81, 811 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 81, 811 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 21, 211 of stannic oxide and electrodes 81, 811 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.



Inventors:
Kohashi, Tadao
Application Number:
US3465202DA
Publication Date:
09/02/1969
Filing Date:
10/17/1966
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
Primary Class:
Other Classes:
345/76, 345/78, 348/800
International Classes:
H05B44/00; (IPC1-7): H05B37/02; H05B39/04; H05B41/14
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