23 September 2008 Highly efficient photometrics tailoring by means of optimized bell-shaped lens arrays
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An innovative optical panel provided with an hexagonal array of refractive lenses having a properly optimized doublecurvature profile has been simulated by ray-tracing and fabricated by injection-moulding. Such lenses are constituted by a concave profile (having negative curvature radius) on their bottom and a convex profile (having positive curvature radius) on their top. We demonstrate that, if compared to refractive elements with conventional geometry, bell-shaped microlenses allow to collect incident rays within a wider angular range (so reducing the number of rays lost by TIR ) and to properly re-direct them. When installed on fluorescent tubes-based professional lighting systems, such refractive elements allow to reduce undesirable glare as prescribed by EN12464-1 Interior Lighting Design Standards and to finely control photometric outputs of luminaries. Besides, bell-shaped microlenses-based films were also simulated to be applied onto a bottom-emitting lambertian OLED. We demonstrate that, by properly tailoring both concave and convex profile shape, it is possible to increase the outcoupling efficiency, as well as the luminous flux emitted by the exit surface, by a factor up to 1.95 and, at the same time, to produce far-field photometric outputs characterized by uniform isocandela distribution maps with an aperture angle up to 60°.
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Michele Manca, Francesco Quercetti, Massimo Gattari, Roberto Cingolani, Giuseppe Gigli, "Highly efficient photometrics tailoring by means of optimized bell-shaped lens arrays", Proc. SPIE 7103, Illumination Optics, 71030E (23 September 2008); doi: 10.1117/12.802628; https://doi.org/10.1117/12.802628

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