The LED lightbulb: are we there yet? progress and challenges for solid state illumination

Author

Holcomb, Man Ochiai ; Mueller-Mach, Regina ; Mueller, Gerd O. ; Collins, Dave ; Fletcher, Robert M. ; Steigerwald, Daniel A. ; Eberle, Stefan ; Lim, Yoke Keem ; Martin, Paul S. ; Krames, Mike

Author_Institution

Lumileds Lighting, San Jose, CA, USA

fYear

2003

fDate

6-6 June 2003

Abstract

Rapid improvement in light emitting diode (LED) performance and an annual multibillion dollar lighting market is motivating worldwide development of LED based illumination systems. In addition to the traditional figures of merit of efficiency and high flux density, the white LED lamps must also have appropriate color characteristics. Current commercial white LED lamps have undesirable color temperatures and uniformity, and inferior color rendering. As discussed below, color uniformity in single phosphor lamps has been improved by deposition of thin uniform phosphor layers conformal to the LED die. Also, 2-phosphor LED lamps with white color characteristics typical of conventional incandescent and halogen sources are described. Furthermore, LED illumination offers additional features not practically achievable with conventional sources.

Keywords

LED lamps; colour; filament lamps; halogens; phosphors; 2-phosphor LED lamps; LED lightbulb; color rendering; color temperatures; color uniformity; halogen sources; incandescent lamps; solid state illumination; thin uniform phosphor layers deposition; white LED lamps; white color characteristics; LED lamps; Light emitting diodes; Lighting; Optical feedback; Optical mixing; Optical pumping; Phosphors; Solid state circuits; Stimulated emission; Temperature;

fLanguage

English

Publisher

ieee

Conference_Titel

Lasers and Electro-Optics, 2003. CLEO '03. Conference on

Conference_Location

Baltimore, MD, USA

Print_ISBN

1-55752-748-2

Type

conf

Filename

1297797