Kyung-mi Moon

Phosphor concentration and geometry for high power white light emitting diode

The most common method of making white light emitting diode (LED) is to mix the blue light from the LED die and the wavelength converted yellow light from the phosphor layer. The color conversion efficiency depends on the geometry and concentration of the phosphor layer including phosphor material. Thus the optimization of the phosphor geometry and concentration make increase the luminous efficiency of the white LED. In this paper, the remote phosphor scheme is optimized focusing on increasing the luminous efficiency in high power. The phosphor layer is separated by the silicone resin from the LED die. The silicone resin covers the LED die with dome shape to increase the extraction efficiency. The phosphor layer has very large volume with dilute concentration. The separation of phosphor layer from LED die and very large volumetric dilute phosphor layer were great important role in increasing the luminous flux. The improved luminous flux was 15% for 1mm2 LED die at 700mA.