A light emitting diode (LED) based light engine that can replace a conventional PAR type bulb with no modifications to a host lighting fixture is provided. The light engine includes a thermally conductive housing including a generally cylindrical wall defining a cavity, an outer surface of the wall includes...http://www.google.co.uk/patents/US7784969?utm_source=gb-gplus-sharePatent US7784969 - LED based light engine
