March 15, 2011…Osram Opto Semiconductors reports that it has set a new laboratory record of 142 lm/W for the efficiency of a warm white LED light source. The LED with a correlated color temperature (CCT) of 2755 K achieves a color 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.
According to the company, the peak value of 142 lm/W was measured under standard conditions. It was achieved at a color perception that the company says very closely matches that of a classic incandescent lamp (color coordinates cx 0.46/ cy 0.41 on the Planckian curve). Osram Opto says that the increase in efficiency was enabled through the combining of new procedures in thin-film and UX:3 chip technologies and in conversion. Further development reportedly benefited from knowledge of epitaxial growth, thin-film chip architectures, conversion processes and package technologies.
“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 mm? 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.”