The Luxeon-exclusive coating process ensures that a uniform layer of phosphor is applied to every facet of the Luxeon LED die, eliminating the varying phosphor thicknesses that cause colour inconsistencies within the beam pattern of white LEDs from other vendors, say the company.
"We wanted to use high-power LEDs in some of our flashlight products to give our customers the maximum light output along with the ruggedness and longevity of solid state lighting, but we rejected most white LEDs because of their poor colour quality," said Robert Galli, CEO of Emissive Energy. "Only Luxeon, with its conformal coating process, came up to our standards. Without it, we would not have been able to bring some of our highest-performing products to market."
The colour uniformity of white Luxeon LEDs compared to other white solid-state light sources is noticeable to the naked eye, say Lumileds, and can also be quantified by measuring the correlated colour temperature (CCT) over the entire 180° LED viewing angle, since the colour variation in conventional LEDs typically manifests itself as a cooler white in the middle with a warmer white or yellowish ring off axis in the light beam. CCT measurements show that conventional white LEDs have roughly 15 times more colour variation than white Luxeon emitters, severely limiting their commercial usefulness.
(Lee Baldock)
