High power LEDs for solid state lighting

For solid stated lighting high light output in combination with high conversion efficacy is essential. High efficiencies are relatively easy to realize at low current densities, but efficiency tends to decline as the current is cranked up. In order to overcome the barriers for high flux LEDs, both epitaxy and chip design have to be optimized. In this paper we report on the improvement of ThinGaN®PowerLED structures in epitaxy, chip design, phosphor efficiency and package design. A key for improving LED performance is understanding the carrier loss mechanisms in blue and green epitaxy structures. Assuming an indirect Auger effect as one of the major loss mechanisms in InGaN LEDs, a reduction of the carrier density per emitting well is enabling efficiency improvement for blue/green LEDs. Along with improved epi designs the extraction efficiency had to be improved. A new chip design allows high current operation in combination with efficiencies beyond 1001m/W for white. New conversion schemes allow the fabrication of extremely efficient green light sources, which enable new generations of high flux projection applications.