INTERNALLY ILLUMINATED SIGN

摘要

An illuminated sign (10), internally illuminated by a source such as one or more LED's (32) generally located at one end, and having a character panel (14) with at least partially transmissive portions to define the characters of the sign. The character panel (14) is curved so as to face the source more squarely at distances further from the source. By this means, the geometric fall-off of illumination with increasing distance from the source is compensated for by the curvature of the character panel, such that more uniform illumination is provided than with prior art flat panels. Power management systems for solar charged illuminated signs are also described, in which the illumination level of the sign is adjusted according to the ambient solar flux and according to the charge-holding capacity of the battery. The system also warns of the impending end of battery life without interrupting the sign functionality.