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Proceedings Paper

Remote phosphor with recycling blue-pass mirror
Author(s): Bill Parkyn; Julio Chaves; Waqidi Falicoff
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Paper Abstract

Phosphor-conversion (PC) LEDs are the leading type of white solid-state lighting (SSL), due to the high efficacy of the yellow wavelengths of blue-stimulated photoluminescence. Conventional phosphor-conversion LEDs have the photoluminescent phosphor in immediate contact with the blue LED. Major types are the thin conformal phosphor and the thick or in-cup phosphor. The first trades away efficiency for increased luminance, while the latter gains efficiency at reduced luminance. In both cases the phosphor suffers from the elevated temperature of the blue chip, particularly the thermal quenching that reduces phosphor quantum efficiency. Also, the inevitable 15% Stokes heat of the phosphor conversion of blue light to longer-wave yellow light adds to the chip's heat load, as does much of a conformal phosphor's back-emission into the chip. It would be preferable to relocate the phosphor away from the chip illuminating it. Although remote phosphors have recently been showcased, their phosphor is much larger than the chip, greatly reducing luminance. A new design is presented of a Dual-Optic-based remote phosphor configuration with minimal increase in phosphor etendue over that of the source, as well as greatly improved spatial uniformity. Moreover, the yellow phosphor back-emission is recycled with a blue-pass mirror that re-illuminates the phosphor to increase its luminance. The result is a new white-light source with superior luminance, efficacy, and uniformity.

Paper Details

Date Published: 8 September 2005
PDF: 12 pages
Proc. SPIE 5942, Nonimaging Optics and Efficient Illumination Systems II, 59420M (8 September 2005); doi: 10.1117/12.619155
Show Author Affiliations
Bill Parkyn, Light Prescription Innovators (United States)
Julio Chaves, Light Prescription Innovators (United States)
Waqidi Falicoff, Light Prescription Innovators (United States)

Published in SPIE Proceedings Vol. 5942:
Nonimaging Optics and Efficient Illumination Systems II
Roland Winston; R. John Koshel, Editor(s)

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