Patent GB-997783-A (GB)
Title: Improvements in or relating to electroluminescent elements
IPC: H05B33/20
Filed: 1961-02-03
Abstract: <PICT:0997783/C1/1> <PICT:0997783/C1/2> A glass enamel contains not more than 17.5 mol. per cent of alkali metal oxide and can have the mol. percentage composition, Li2O-5, Na2O-10, CaO-6, SrO-4.5, ZnO-14.5, TiO2-3.5, Al2O3-3.5, SiO2-23, B2O3-30. The electroluminescent device shown in Fig. 1 comprises a metal carrier 1 including a surface layer 2 consisting of zirconium, titanium, tantalum, aluminium or chromium which form a coherent surface oxide film 3 adherent to the metal, a layer 4 of glass enamel upon the surface layer of the carrier, in which glass enamel layer electroluminescent material is embedded, and a transparent conductive layer 5 of tin oxide serving as an electrode on the side of the glass-enamel layer remote from the carrier.  The oxide film can be about 4000 <\>rA or about 0.2 micron thick.  The thickness of the metal surface layer on the carrier should be at least several hundreds of Angstrom units.  The layer 5 is provided with a glass layer 6.  The metal carrier 1 can comprise chromium-plated metal, a body of iron covered with a layer of the surface metal, or a body of iron covered with a nickel layer and/or a copper layer covered in turn with a chromium layer. The glass enamel layer can have a thickness of from 20 to 80 microns and can be a composite layer 15, Fig. 2, comprising a first layer 16 adjacent to the metal carrier 11 and containing titanium dioxide pigment, and a second layer 17 remote from the metal carrier and containing the electroluminescent material.  The first layer 16 can have a thickness of from 5 to 50 microns and a content of titanium dioxide pigment of from 5 to 20% by volume.  The second layer 17 can have a thickness of from 15 to 50 microns and a content of electroluminescent material of from 20 to 50% by volume.  Specification 997,782 is referred to.ALSO:<PICT:0997783/C4-C5/1> <PICT:0997783/C4-C5/2> An electroluminescent device comprises a metal carrier 1 including a surface layer 2 consisting of zirconium, titanium, tantalum, aluminium or chromium which form a coherent surface oxide film 3 adherent to the metal, a layer 4 of glass enamel upon the surface layer of the carrier, in which glass-enamel layer electroluminescent material is embedded, and a transparent conductive layer 5 of tin oxide serving as an electrode on the side of the glass-enamel layer remote from the carrier.  The oxide film can be about 4000 <\>rA or about 0.2 micron thick.  The thickness of the metal surface layer on the carrier should be at least several hundreds of Angstrom units. The layer 5 is provided with a glass layer 6. The metal carrier 1 can comprise chromiumplated metal, a body of iron covered with a layer of the surface metal, or a body of iron covered with a nickel layer and/or a copper layer covered in turn with a chromium layer. The glass-enamel layer can have a thickness of from 20 to 80 microns and can be a composite layer 15, Fig. 2, comprising a first layer 16 adjacent to the metal carrier 11 and containing titanium dioxide pigment, and a second layer 17 remote from the metal carrier and containing the electroluminescent material.  The first layer 16 can have a thickness of from 5 to 50 microns and a content of titanium dioxide pigment of from 5 to 20% by volume. The second layer 17 can have a thickness of from 15 to 50 microns and a content of electroluminescent material of from 20 to 50% by volume.  The electroluminescent material can be zinc sulphide activated with copper, silver, gold or manganese and coactivated with aluminium or chlorine.  The glass enamel layer can contain not more than 17.5 mol. per cent of alkali metal oxide and can have the mol. percentage composition, Li2O-5, Na2O-10, CaO-6, SrO-4.5, ZnO-14.5, TiO2-3.5, Al2O3-3.5, SiO2-23 B2O3-30. Specification 997,782 is referred to.