The energy-efficient use of LED light requires the development of compact illumination systems for the customized homogenization and shaping of partially-coherent LED light. Therefore a design concept which is based on arrays of aperiodic micro structures, namely cells, for primary or secondary optics is introduced. Each cell of the array deflects locally the light into predefined directions and results in a light spot in the target plane. The light spots of all array cells together form the desired light pattern. The performance of three different cell geometries (linear gratings, micro prisms andmicromirrors) on the homogenization and shaping ofmonochromatic as well as white light LEDs is demonstrated. For the realistic evaluation of the illumination system an LED model including power spectrum, polarization, spatial and temporal coherence is chosen. Furthermore wave-optical effects like diffraction at the cell apertures are taken into account. For the grating cells arrays a rigorous analysis of the diffraction efficiencies is included.

Date Published: 9 March 2015
PDF: 8 pages
Proc. SPIE 9383, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XIX, 93831B (9 March 2015); doi: 10.1117/12.2079064

Published in SPIE Proceedings Vol. 9383:
Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XIX
Klaus P. Streubel; Heonsu Jeon; Li-Wei Tu; Martin Strassburg, Editor(s)