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Proceedings Paper

Virtual filaments that mimic conventional light bulb filaments
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Paper Abstract

Conventional incandescent light bulbs have a wire filament acting as an extended light source with nearly constant intensity throughout its quasi-spherical emission pattern. Here we present a novel family of optical devices that make use of commercially available Lambertian or near-Lambertian LED light sources, in conjunction with tailored optical element bonded to the top surface of the LED. These hybrid devices can emulate the output of traditional incandescent filaments, or can be designed to produce a wide range of light output beam patterns. We call these new devices Virtual Filaments, as they can be designed to appear the same as an incandescent filament, with a similar light output pattern, and having a similar focal position above the base. These new lamps can then be used in the same applications as those they replace, thus eliminating the need to redesign or replace the original luminaire. We present several possible optical designs that can be used with a number of standard LEDs to replace standard incandescent bulbs. In one example we show a design that provides an output with near-uniform intensity across a full beam angle of 300 degrees, from a focal position 20 mm above an LED. Other major advantages of these new devices include their ability to be given sharp cutoffs, to homogenize non-uniform LED light sources and to color-mix the output of RGB LEDs.

Paper Details

Date Published: 29 September 2004
PDF: 10 pages
Proc. SPIE 5529, Nonimaging Optics and Efficient Illumination Systems, (29 September 2004); doi: 10.1117/12.561570
Show Author Affiliations
Julio Chaves, Light Prescriptions Innovators, LLC (United States)
Fernando Munoz, Light Prescriptions Innovators Europe (Spain)
Juan Carlos Minano, Light Prescriptions Innovators Europe (Spain)
Pablo Benitez, Light Prescriptions Innovators Europe (Spain)
Bill Parkyn, Light Prescriptions Innovators, LLC (United States)
Waqidi Falicoff, Light Prescriptions Innovators, LLC (United States)
Yupin Sun, Light Prescriptions Innovators, LLC (United States)

Published in SPIE Proceedings Vol. 5529:
Nonimaging Optics and Efficient Illumination Systems
Roland Winston; R. John Koshel, Editor(s)

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