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Osram Opto Semiconductors announces efficiency record achieved for warm white LED light source


March 21, 2011
By Alyssa Dalton
The laboratory setup for a warm white LED achieves a peak value of 142 lm/W directly on the Planckian curve at 2700 K; an optimized setup at 3000 K could achieve 160 lm/W.

March 21, 2011

Osram Opto Semiconductors has announced that it has set a new laboratory record of 142 lm/W for a warm white LED light source. With a correlated colour temperature (CCT) of 2755 K the LED achieves a colour rendering index (CRI) of 81. Measurements were taken under standard conditions: room temperature and pulsed mode at an operating current density of 350 mA/mm², said Osram Opto Semiconductors.

The laboratory setup for a warm white LED shows the potential of energy-saving semiconductor light sources. According to Osram Opto Semiconductors, the peak value of 142 lm/W measured under standard conditions is achieved at a color perception that very closely matches that of a classic incandescent lamp (color coordinates cx 0.46/ cy 0.41 on the Planckian curve).

“If we explore this technical approach further and allow deviations from the Planckian curve we should even now be able to achieve higher efficiency values of up to 160 lm/W for a correlated color temperature of 3000 K (cx 0.45/ cy 0.44),” said Dr. Norwin von Malm, predevelopment manager at Osram Opto Semiconductors. “If we apply this approach to a 2 mm² chip we can improve efficiency by a further 10 to 15 percent for the same operating current. We would then expect 180 lm/W for a pure warm white LED and good color rendering.”