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Micro optical pattern shaping for tailored light emission from organic LEDs

: Danz, Norbert; Wächter, Christoph; Michaelis, Dirk; Dannberg, Peter; Flämmich, Michael

Postprint (1 MByte; PDF; )

Optics Express 20 (2012), Nr.12, S.12682-12691
ISSN: 1094-4087
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IOF ()

The application of large area OLEDs for lighting and signage purposes potentially requires essential changes of the common Lambert-like emission pattern. We demonstrate an array based micro optical approach for pattern shaping of area light sources based on distorted Fourier imaging of an aperture array with a micro lens array. Narrow angular emission patterns of ± 35° and ± 18° FWHM obtained experimentally demonstrate the pattern shaping with low stray light levels. The internal recycling of initially rejected photons yields intensity enhancements exceeding a factor two in forward direction that is still well below the theoretical limits due to limited reflectivity.