A light-responsive light-emitting diode display comprises a light-emitting diode circuit including a series connection of light-emitting diodes and a light-responsive current-controlling circuit connected in series to said light-emitting diode circuit for supplying a current thereto in correspondence...http://www.google.com/patents/US4329625?utm_source=gb-gplus-sharePatent US4329625 - Light-responsive light-emitting diode display
