Abstract A method is disclosed for making multi-component phosphor structures whose emission color depends on the energy of the electrons used to excite them. The method comprises the mixing of two or more component phosphors, each component phosphor having particles with non-luminescent interior core regions and nonluminescent exterior surface regions separated by a luminescent region, the region dimensions and emission color of each component being distinct. These structures are formed by diffusing activating and/or coactivating impurities partially into the particles, or by growth of activated material on the outside of non-luminescent material, and by the subsequent diffusion of luminescence killing impurities partially into the luminescent region.
An electron energy sensitive phosphor as recited in claim 1 wherein said phosphor particle has a substantially non-luminescent outer region surrounding said luminescent region and wherein said phosphor is characterized by an efficienCy of emission which is a maximum at a first predetermined electron energy and which is substantially zero below a second lower predetermined electron energy.
Claim 2
Dependent Claim
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An electron energy sensitive phosphor as recited in claim 1 wherein said phosphor comprises a composition of zinc cadmium sulfide, ZnxCd(1 x)S, where x varies from zero to 1.
Claim 3
Dependent Claim
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An electron energy sensitive phosphor as recited in claim 3 wherein said luminescent region contains a selectively activated region of the material selected.
Claim 4
Dependent Claim
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An electron energy sensitive phosphor as recited in claim 4 wherein an activator is selected from the group consisting of salts of silver, copper and gold.