A lighting device comprises groups of solid state light emitters, a sensor and circuitry. If the emitters are illuminated, the sensor is exposed to combined light from the groups, and senses only a portion of the combined light. The circuitry adjusts current applied to at least one of the emitters based...http://www.google.ca/patents/US20080309255?utm_source=gb-gplus-sharePatent US20080309255 - LIGHTING DEVICES AND METHODS FOR LIGHTING
