US Patent 7631988 LED lamp

An LED lamp comprises an envelope, two heat sinks respectively disposed at two opposite ends of the envelope, two LED modules respectively received in the two heat sinks, and two light guide plates respectively mounted in the two heat sinks and over the LED modules. Each light guide plate is located at a light route of the LED module to reflect light emitting from the LED module into several light beams. The light beams are first emitted into a central hole of the envelope, spread on an interior of the envelope around the central hole and radiate out of the LED lamp from an exterior of the envelope. The central hole has a round shape, while the exterior has a triangular shape.