Open AccessMicro optical pattern shaping for tailored light emission from Organic LEDs
Author(s) -
Norbert Danz,
Christoph Wächter,
Dirk Michaelis,
Peter Dannberg,
Michael Flämmich
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.012682
Subject(s) - optics , light emitting diode , aperture (computer memory) , stray light , light intensity , lens (geology) , photon , numerical aperture , nonimaging optics , led lamp , optoelectronics , materials science , physics , wavelength , acoustics
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.