Fraunhofer Institute for Applied Optics and Precision Engineering IOF
Optics
Recent progress in high-power LED development enables new approaches for illumination tasks.
The required optics is usually composed of a collimating and a beam shaping element. Efficient collimation is achieved with concentrators, while beam shaping fly´s eye condensers provide homogeneous illumination of circular, square or oblong areas or line foci. These homogenizers are realized with tandem microlens arrays, providing high system transmission, minimum loss of etendue and very short system length. Stray light suppression for hexagonally packed circular lenslet arrays is achieved by buried absorbing aperture arrays.
Manufacturing
Concentrators are manufactured by injection molding. For prototyping, direct diamond-turning of PMMA offers short development cycle times. Tandem lens arrays are replicated reflow lenses with numerical apertures up to 0.25. Replication is carried out into UV-curing polymer on both sides of a float glass substrate wafer. Alternative technologies are injection molding or hot embossing of plastics or glass.
Competencies
- Design and prototyping of miniaturized illumination system
- Support for assessment of large scale manufacturers