Remote Pyramid-Shaped Phosphor Coating for Phosphor-Converted White LEDs
Abstract
Increasing light extraction efficiency is an important task when it comes to
manufacturing a powerful white light emitting diode with high luminous flux
per watt. In this paper the fabrication of a pyramid-shaped 3-dimensional
phosphor coating is reported. It is represented by a phosphor cover, shaped
into an array of pyramid like formations. It is proposed that such a structure
can improve the light extraction efficiency and the color distribution characteristics
of any phosphor-converted white LED. The luminous flux and luminous
efficacy are being studied as a function of the forward current across
the die. It was found out that with this kind of technique it was possible to
achieve an 8% - 14% increase in the efficacy of the pc-LED. This increase of
light output power is being attributed to the reduction of the phenomena of
total internal reflection (TIR) inside the packaging module