Electroluminescent cell and variable frequency source for selective excitation of contrastingly-responsive phosphor components thereof

Claim 1

THE COMBINATION WHICH COMPRISES: (A) A SOURCE OF ALTERNATING ELECTRIC POTENTIAL HAVING AN OUTPUT OF VARIABLE FREQUENCY, A RELATIVELY LOW FREQUENCY ELECTRIC POTENTIAL CONSTITUTING ONE OUTPUT OF SAID SOURCE, AND A RELATIVELY HIGH FREQUENCY ELECTRIC POTENTIAL CONSTITUTING ANOTHER OUTPUT OF SAID SOURCE; (B) AN ELECTROLUMINESCENT CELL COMPRISING, SPACED ELECTRODES AT LEAST ONE OF WHICH IS LIGHT TRANSMITTING, AND A MIXTURE OF PREDETERMINED AMOUNTS OF TWO DIFFERENT ELECTROLUMINESCENT PHOSPHORS INCLUDED BETWEEN SAID SPACED ELECTRODES; (C) MEANS FOR SELECTIVELY APPLYING A DESIRED ONE OF SAID OUTPUTS OF SAID SOURCE ACROSS SAID SPAED ELECTRODES OF SAID CELL, A RELATIVELY HIGH FREQUENCY ELECTRIC FIELD IMPOSED ACROSS SAID MIXED PHOSPHORS BY APPLICATION OF SAID RELATIVELY HIGH FREQUENCY ALTERNATING ELECTRIC POTENTIAL ACROSS SAID SPACED ELECTRODES, AND A RELATIVELY LOW FREQUENCY ELECTRIC FIELD IMPOSED ACROSS SAID MIXED PHOSPHORS BY APPLICATION OF SAID RELATIVELY LOW FREQUENCY ALTERNATING ELECTRIC POTENTIAL ACROSS SAID SPACED ELECTRODES; (D) SAID SOURCE AND SAID CELL COOPERATING IN THE FOLLOWING MANNER, ONE OF SAID MIXED PHOSPHORS RESPONDING TO EXCITATION BY SAID RELATIVELY LOW FREQUENCY ELECTRIC FIELD TO ELECTROLUMINESCE TO PRODUCE AN INDIVIDUAL COLOR, THE OTHER OF SAID MIXED PHOSPHORS RESPONDING TO EXCITATION BY SAID RELATIVELY HIGH FREQUENCY ELECTRIC FIELD TO PRODUCE AN INDIVIDUAL COLOR WHICH SHARPLY CONTRASTS WITH THE COLOR IN WHICH SAID ONE PHOSPHOR ELECTROLUMINESCES WHEN ENERGIZED BY SAID RELATIVELY LOW FREQUENCY ELECTRIC FIELD, SAID ONE PHOSPHOR ELECTROLUMINESCING MORE BRIGHTLY THAN SAID OTHER PHOSPHOR WHEN SAID MIXED PHOSPHORS ARE ENERGIZED BY SAID RELATIVELY LOW FREQUENCY ELECTRIC FIELD, AND SAID OTHER PHOSPHOR ELECTROLUMINESCING MORE BRIGHTLY THAN SAID ONE PHOSPHOR WHEN SAID MIXED PHOSPHORS ARE ENERGIZED BY SAID RELATIVELY HIGH FREQUENCY ELECTRIC FIELD.