Light emitting device having increased light output

摘要

The light intensity emitted from a package is increased by adjusting a portion of the package encapsulant so that light impacting the side walls of the adjusted encapsulant portion will encounter total internal reflection (TIR) with the reflected light directed toward the top surface of the package. The adjusted portion of the package is positioned so that air can be used as the second (exterior) medium with the critical TIR angle being such that light emitted from a light source (such as from an LED die) will be directed primarily so as to escape the package from the top surface as opposed to being scattered internal to the package. In one embodiment, a lower portion of the encapsulant is surrounded by a casing to inwardly direct light from the light source that impacts the side of the encapsulant with an angle less than the critical TIR angle.