A variable color complementary display device includes a plurality of display areas arranged in a pattern for selectively exhibiting a plurality of display units. Each display area includes a plurality of pairs of light emitting diodes for emitting, when forwardly biased, light signals of respective...http://www.google.com/patents/US6414662?utm_source=gb-gplus-sharePatent US6414662 - Variable color complementary display device using anti-parallel light emitting diodes
