Electroluminescent compositions

Claim 1

AN ELECTROLUMINESCENT DEVICE COMPRISING A PAIR OF ELECTRICALLY CONDUCTING ELECTRODES, AT LEAST ONE OF WHICH IS TRANSLUCENT, AND THEREBETWEEN A SEMI-DIELECTRIC LAYER OF AN ELECTROLUMINESCENT COMPOSITION, THE ACTIVE COMPONENTS OF WHICH CONSIST ESSENTIALLY OF A MIXTURE OF METAL OXIDES IN THEIR CRYSTALLINE STATE, AT LEAST ONE OF SAID OXIDES HAVING A LUMINESCENCE WHICH IS PRODUCED BY ACTIVATION THEREOF BY THE ELECTRONIC EMISSION FROM ANOTHER OXIDE IN SAID MIXTURE, THE PROPORTION OF THE SECOND ACTIVATING OXIDE NOT EXCEEDING 1% BY WEIGHT BASED ON THE WEIGHT OF THE ACTIVATED OXIDE, THE ACTIVATED OXIDE BEING SELECTED FROM THE CLASS CONSISTING OF ZINC, CADMIUM, BARIUM AND CALCIUM OXIDES, WHILE THE ACTIVATING OXIDE IS SELECTED FROM THE CLASS CONSISTING OF MANGANESE, LEAD, COPPER, SILVER, THALLIUM AND GERMANIUM OXIDES, AND SAID ELECTROLUMINESCENT COMPOSITION FURTHER CONTAINING A SMALL AMOUNT OF UNCOMBINED OXYGEN RESULTING FROM THE CRYSTALLIZATION OF A POWDERERD MIXTURE OF SAID OXIDES IN AN ATMOSPHERE OF PURE OXYGEN AT A SUB-ATMOSPHERIC PRESSURE.