Tailored edge-ray design for illumination with extended sources

A. Rabl, J. M. Gordon, Ong Pang Teng, H. Ries, R. Winston

    Research output: Contribution to journalConference articlepeer-review

    2 Scopus citations


    The goal of the optical design of luminaires and other radiation distributors is to attain the desired illumination on the target with a given source. Usually there are constraints that should be satisfied, such as avoiding glare, maximizing the optical efficiency and respecting practical size limitations (not to mention considerations of fabrication costs, availability of materials and esthetics). While the required design procedure is well known for situations where the source can be approximated as a point or as a line, the development of an explicit analytical design method (as opposed to numerical search) for extended sources has begun only a few years ago. A solution for extended isotropic sources can be obtained by establishing a one-toone correspondence between target points and edge rays, using the tools of nonimaging optics. The designs are called TED (tailored edge-ray designs). Particular solutions have been found in separate papers by Ries and Winston1,2 and by Gordon, Rabl and Ong 3-6. The present paper presents a topological classification of all possible solutions in two dimensions and discusses their general characteristics. We show that any illumination distribution can be obtained exactly in the central region of the target, but in general there will be a certain amount of spillover outside this region. Some flexibility for tailoring designs to specific requirements (size, glare control, etc.) can be gained by the choice of the solution type, the choice of the boundary conditions, and by the use of hybrid configurations that combine several types of solution. The design method is illustrated with specific examples.

    Original languageEnglish
    Pages (from-to)246-261
    Number of pages16
    JournalProceedings of SPIE - The International Society for Optical Engineering
    StatePublished - 1 Nov 1996
    EventCurrent Developments in Optical Design and Engineering VI 1996 - Denver, United States
    Duration: 4 Aug 19969 Aug 1996


    • Edge-ray
    • Extended sources
    • Glare control
    • Illumination
    • Luminaire
    • Nonimaging optics
    • Reflector design

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Computer Science Applications
    • Applied Mathematics
    • Electrical and Electronic Engineering


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