Osram Opto demonstrates 142 lm/W warm-white LED

The R&D result was measured under standard conditions at room temperature and the LED had a CCT of 2755K with a color point on the Planckian curve.

Mar 15th, 2011
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Osram Opto Semiconductors claims to have set a new laboratory record of 142 lm/W for the efficiency of a warm-white LED light source.

The LED had a correlated color temperature (CCT) of 2755 K, the LED has a color-rendering index (CRI) of 81.

Measurements were taken under standard conditions at room temperature and under pulsed-mode operation at an operating current density of 350 mA/mm2.

The laboratory setup for a warm white LED
Bright warm-white light with high efficiency is particularly important for lighting applications in the residential sector. The peak value of 142 lm/W measured under standard conditions is achieved at a color point – with color coordinates of (x=0.46, y=0.41) on the Planckian curve - that very closely matches the perception of a classic incandescent lamp.

“If we explore this technical approach further, and allow deviations from the Planckian curve, we should be able to achieve higher efficiency values of up to 160 lm/W for a CCT of 3000 K at (x=0.45, y=0.44),” said 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 with good color rendering.”

The increase in efficiency was made possible by combining new procedures in thin-film and UX:3 chip technologies and in conversion (i.e. phosphor technology). Osram Opto says that its development engineers have benefited from combined know-how in all aspects of the production process. These include epitaxial growth, thin-film chip architectures, conversion processes and package technologies.

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