Interchangeable lenses allow for differentiated light distribution in ...
+++++This article was published in the June 2011 issue of LEDs Magazine. View the Table of Contents and download the PDF file of the complete June 2011 issue.
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Discussions concerning the efficiency of LED lighting largely revolve around the high luminous efficacy of the semiconductor light sources. As a result, the potential of the light-guidance system is often pushed into the background. However, while the development of increasingly more efficient LEDs occupies the research laboratories of the major corporations in the electronics industry, the optimisation of LED technology gives luminaire manufacturers the chance to optimize their own lighting engineering and to provide users with definite advantages in terms of lighting quality, flexibility and economic efficiency.
The optical systems for LED lighting products are very different from conventional luminaires with reflector technology. Because transmission with lenses is more efficient than reflection with reflectors, LED luminaires fitted with the appropriate lens systems deliver a better light output ratio. In architectural lighting, interchangeable Spherolit lenses offer the big advantage that differentiated light distributions can be obtained. Alternative lenses can be exchanged simply to suit altered lighting tasks with one and the same luminaire.
Spherolit technology
As described in this article, lighting manufacturer Erco has developed Spherolit lenses for LED optical systems.
Spherolit technology is based on dividing up a large lens surface into individual, three dimensionally domed facets that control the light using refraction. By individually shaping each “spherolite” facet, the characteristics of the lens can be extensively controlled. Depending on the curvature of each individual facet, the parallel incident light is dispersed to a greater or lesser extent. This results in different lenses that, for the same basic geometry, can have different beam angles ranging from “narrow spot” to “wide flood.” Made of optical polymer, the lenses are extremely high precision components and place exacting demands on tool making and on manufacturing via the injection-molding process.
Photometric systems
The quality of an optical system has a major influence on the overall efficiency of an LED luminaire.
Large Fresnel Lens - News
In contrast to normally- used collimators, therefore, the middle lens section in this case is replaced by a Fresnel lens of reduced component thickness in order to simplify the injection molding process (Fig. 4). However, the very narrow-beam light
as he walks over to a large glass fixture rotating inside an encased closing. He opens the door to the glass box and walks in, "abrass oil lamp went right in the middle of this lense here," said Enright. The Fresnel lens, on loan from the US Coast
many finding their way to large corporations such as Campbell's Soup. Other great facts came when we passed the Absecon Lighthouse. Most of us from the area know about the 228 steps to the top, and that it still has its original Fresnel lens.
As many lives as the 6 1/2-foot, handcrafted Fresnel lens has saved over the years, the early warning system wasn't foolproof. Lying submerged beneath the waves are thousands of hidden rocks and reefs that have claimed far too many human lives and
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Greenpowerscience.com This is a large Fresnel Lens focused on a copper tube with a 12 V pump (powered by two 6 watt solar panels) with water circulating through the unit. Water, seven gallons, was raised from 63 F to 106 F in one hour. It is not super efficient as heat is lost at the open top of the glass tank. This is designed to illustrate one method of solar heating a swilling pool with a Large Fresnel Lens. TESTING HDD AQUA BLOCK.
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Nonimaging Fresnel lenses, design and performance of solar concentrators
This book offers a detailed and comprehensive account of the engineering of the world's first nonimaging Fresnel lens solar concentrator.Solar Energy Projects for the Evil Genius
Note Very large Fresnel lenses can generate truly awesome power—start the experiments in this chapter with smaller Fresnel lenses such as those used as ...Lighthouses for Kids, History, Science, and Lore with 21 Activities
As you hold a cell phone or music player in your palm, it may be hard to comprehend just how large Fresnel lenses had to be to do their job. ...Beamed energy propulsion, First International Symposium on Beamed Energy Propulsion : Huntsville, Alabama, 5-7 November 2002
Large Space Telescopes Using Fresnel Lens For Power Beaming, Astronomy and Sail Missions James T. Early Lawrence Livermore National Laboratory, ...Encyclopedia of optical engineering
Because these curves are not flat across large bandwidth regions, refractive fresnel lenses tend to have large chromatic aberrations. ...Information Today Directory
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Fresnel lens - Wikipedia, the free encyclopedia
The design allows the construction of lenses of large aperture and short focal length without the mass and ... to conventional bulky lenses, the Fresnel lens is much thinner, ...
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