Optical device for semiconductor based lamp

摘要

An optical device for a semiconductor based lamp includes a base and a semiconductor based light-emitting device mounted on the base. A transparent body encapsulates the semiconductor based light-emitting device. A reflective surface is in contact with the transparent body and covers a predetermined region on a top of the transparent body. The reflective surface has an opening. At least a portion of the transparent body protrudes through the opening in the reflective surface. Light emitted from the semiconductor based light-emitting device transmits upwardly through the opening in the reflective surface.