Cree's High-Power White LED Delivers 121 lm/W
Cree's commercial high-power white LEDs can now deliver 121 lm/W at 35A/cm2 current density. These particular Cree XLamp® XP-G LEDs deliver 267 lumens at a drive current of 700 mA and an operating voltage of 3.14 V, and generate white light with a CCT of 6850K and a CRI of 72. These XLamp XP-G LEDs are based on Cree's latest generation EZBright® LED chip platform, the first generation of which was developed in part with funding from DOE.
In a separate DOE-funded project that was recently completed, Cree focused on developing LED chips incorporating photonic crystal elements for improved light extraction and novel package technology for higher down-conversion efficiency compared with conventional LEDs. This work ultimately resulted in a 15 percent brightness increase for packaged blue LEDs, compared with the baseline at the start of the two-year project.
The blue chip wall plug efficiency has the greatest improvement potential for white LEDs, since their performance depends on the quality of the blue LED light engine. White LEDs are produced by combining one or more saturated-color LEDs with a phosphor or other light down-converting media to achieve white broad-band illumination. Part of the challenge is moving the efficacy curve up at a reasonable cost. Improving the blue LED provides the broadest access of performance leverage to the applications base and benefits stakeholders at the various levels in the SSL value chain (chips, components, and systems).