US Patent 8444299 Dimmable LED bulb with heatsink having perforated ridges

A light-emitting diode lamp includes a light engine, a power assembly, and a heatsink. The light engine includes a plurality of light-emitting diodes, and the power assembly includes a socket disposed at one end of the power assembly and a heat spreader plate disposed at another end of the power assembly opposite the socket. The light engine is mounted to the heat spreader plate. The power assembly further includes a power supply circuit that is electrically coupled to the socket and to the light engine. The socket is configured to electrically couple the power supply circuit to an external electrical source. The heatsink encircles the power assembly and is thermally connected to the light engine. The heatsink also includes a plurality of perforations, which are arranged to facilitate a natural convection airflow over and through the heatsink.