Electroluminescent digital display device

Claim 1

AN ELECTROLUMINESCENT DIGITAL-TYPE DISPLAY DEVICE, COMPRISING A TRANSPARENT ELECTRICALLY INSULATING SUBSTRATE PLATE BEARING A SERIES OF SPACED APART INDICIA, A FIRST LAYER AT LEAST PARTIALLY OVERLYING ONE SIDE OF SAID PLATE AND HAVING RESPECTIVE PORTIONS ALIGNED WITH EACH OF SAID INDICIA, SAID FIRST LAYER BEING FORMED OF A SUBSTANTIALLY TRANSPARENT MATERIAL CAPABLE OF CARRYING AN ELECTRICAL CURRENT BUT HAVING A SUBSTANTIAL ELECTRICAL RESISTANCE, A SECOND ELECTRICALLY CONDUCTIVE LAYER ALIGNED WITH BUT SPACED FROM SAID FIRST LAYER, ELECTROLUMINESCENT PHOSPHOR MEANS DISPOSED IN THE SPACE BETWEEN SAID LAYERS AND BEING ELECTRICALLY INSULATED FROM SAID LAYERS, A SERIES OF SPACED ELECTRICAL CONTACT ELEMENTS MOUNTED ON SAID PLATE AND EACH BEING IN ELECTRICAL CONTACT WITH SAID FIRST LAYER AND IN ALIGNMENT WITH A RESPECTIVE ONE OF SAID INDICIA, AND MOVABLE ELECTRICAL CONTACT MEANS ARRANGED TO TRAVERSE SUCCESSIVELY SAID CONTACT ELEMENTS, THE ELECTRICAL RESISTANCE OF SAID FIRST LAYER AND THE SPACINGS BETWEEN SAID CONTACT ELEMENTS AND SAID PORTIONS OF SAID FIRST LAYER ALIGNED WITH SAID INDICIA BEING SELECTED SO THAT WHEN AN ENERGIZING POTENTIAL IS APPLIED TO SAID MOVABLE CONTACT MEANS AND TO SAID SECOND LAYER THE RESULTING ILLUMINATION OF THE INDICIA ALIGNED WITH THE CONTACT ELEMENT CONTACTED BY SAID MOVABLE CONTACT MEANS WILL BE SUBSTANTIALLY GREATER THAN THE ILLUMINATION OF ALL OTHERS OF SAID INDICIA AND SO THAT AN ILLUMINATION GRADIENT WILL EXIST BETWEEN THE INDICIA ALIGNED WITH THE CANTACT ELEMENT CONTACTED BY SAID MOVABLE CONTACT MEANS AND ADJACENT INDICIA.