Theory
Early academic research in nonimaging optical mathematics seeking closed form solutions was first published in textbook form in a 1978 groundbreaking book. A modern textbook illustrating the depth and breadth of research and engineering in this area was published in 2004. A thorough introduction to this field was published in 2008.
Special applications of nonimaging optics such as Fresnel lenses for solar concentration or solar concentration in general have also been published, although this last reference by O'Gallagher describes mostly the work developed some decades ago. Other publications include book chapters.
Imaging optics can concentrate sunlight to, at most, the same flux found at the surface of the sun. Nonimaging optics have been demonstrated to concentrate sunlight to 84,000 times the ambient intensity of sunlight, exceeding the flux found at the surface of the sun, and approaching the theoretical (2nd law of thermodynamics) limit of heating objects up to the temperature of the sun's surface.
The simplest way to design nonimaging optics is called "the method of strings", based on the edge ray principle. Other more advanced methods were developed starting in the early 1990s that can better handle extended light sources than the edge-ray method. These were developed primarily to solve the design problems related to solid state automobile headlamps and complex illumination systems. One of these advanced design methods is the Simultaneous Multiple Surface design method (SMS). The 2D SMS design method (U.S. Patent 6,639,733) is described in detail in the aforementioned textbooks. The 3D SMS design method (U.S. Patent 7,460,985), the most advanced design approach to date, was developed in 2003 by a team of optical scientists at Light Prescriptions Innovators.
Read more about this topic: Nonimaging Optics
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