Design Method for a Total Internal Reflection LED Lens with Double Freeform Surfaces for Narrow and Uniform Illumination
| Autor: | Jae-Hyeung Park, Se-Geun Park, Seung Gol Lee, Beom-Hoan O, Jae Suk Yang |
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| Rok vydání: | 2016 |
| Předmět: |
Surface (mathematics)
Total internal reflection Materials science Differential equation business.industry Physics::Optics Astrophysics::Cosmology and Extragalactic Astrophysics 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Atomic and Molecular Physics and Optics law.invention 010309 optics Lens (optics) Luminous flux Optics law 0103 physical sciences Ray tracing (graphics) 0210 nano-technology business |
| Zdroj: | Journal of the Optical Society of Korea. 20:614-622 |
| ISSN: | 1226-4776 |
| Popis: | In this paper, we propose a novel differential equation method for designing a total internal reflection (TIR) LED lens with double freeform surfaces. A complete set of simultaneous differential equations for the method is derived from the condition for minimizing the Fresnel loss, illumination models, Snell's Law of ray propagation, and a new constraint on the incident angle of a ray on the light-exiting surface of the lens. The last constraint is essential to complete the set of simultaneous differential equations. By adopting the TIR structure and applying the condition for minimizing the Fresnel loss, it is expected that the proposed TIR LED lens can have a high luminous flux efficiency, even though its beam-spread angle is narrow. To validate the proposed method, three TIR LED lenses with beam-spread angles of less than 22.6° have been designed, and their performances evaluated by ray tracing. Their luminous flux efficiencies could be obviously increased by at least 35% and 5%, compared to conventional LED lenses with a single freeform surface and with double freeform surfaces, respectively. |
| Databáze: | OpenAIRE |
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