A light emitting sign comprising a light box housing a plurality of blue LEDs operable to generate blue excitation light and a light emitting display surface overlaying the light box opening. The light emitting display surface comprises a light transmissive substrate configured as a light transmissive window such that light generated by the sign is emitted from the substrate and a phosphor overlaying at least a portion of one face of the substrate. The phosphor is configured to absorb at least a portion of the blue light generated by the LEDs and, in response, to emit light of a selected color.