Importance of efficacy
The efficiency of transforming electrical energy into visible light is one of the crucial parameters for lighting applications. Since 19% of worldwide energy consumption is accounted for lighting applications, there is a clear demand for all lighting technologies to achieve greater efficiency.
Conventional lamp technologies have already derived standards for the measurement of lighting efficiency. However, the field is still open for OLED light sources. “It is very important for a new lighting technology such as OLEDs to have early clear standards defined for its most important light parameters,” says Karsten Diekmann of Osram Opto Semiconductors, co-author of the white paper. "The OLED lamp as a large-area, flat light source bears already a high degree of final luminaire characteristics. Therefore we want to set a standard for its efficacy, so that all early adopters of OLED lighting technology have a good expectation of what light output they can expect”.
In May this year, the OLLA project reported OLEDs with an efficacy of 25 lm/W, which is twice as efficient as a standard incandescent lamp. Several other groups have reported even higher figures, but without mentioning how these figures were measured.
This article was published in the November/December 2007 issue of LEDs Magazine.
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