Building on developments achieved through multiple DOE-funded R&D projects, Lumileds’ warm-white high-power LEDs now exceed the SSL program milestone of 210 lm/$. At a CCT of 3000K and CRI of 80, Lumileds’ LUXEON TX can produce more than 260 lumens under the normalized condition of 1 W/mm² (2 watts of input power from a 2 mm² die). At current pricing this corresponds to 210 lm/$ or better. The metric - lumens per dollar (lm/$) - reflects advancements in both efficacy and pricing. Increases in efficacy result in increased light output per LED package and improvements in manufacturing result in reductions in production costs and pricing. Achieving this milestone in a high-power LED means that the associated cost and performance benefits are now available not only in non-directional lighting applications (which are often served by mid-power LEDs) but also in directional applications, which require a small source size and optimized angular radiation distribution.

The advancements that enabled this performance include various improvements in efficacy in multiple areas of the package. Advancements were made to the epitaxial design and growth process, which improved internal quantum efficiency. At the die level, improvements were made to the reflectance of the p-contact, which increases light extraction efficiency. Finally, package level advancements were made at the phosphor/silicone layer resulting in improved phosphor conversion efficiency and package efficiency. This progress resulted in a 9% gain in efficacy (lm/W) without increasing production costs, resulting in advancement of the combined metric – lm/$. (September 2017)