Patent · US Expired

LED lighting system for producing white light

US6234645A · kind A · utility

225Cited by

4References

8Claims

0Family size

Assignee

U.S. Philips Corporation · US

Inventors

Herbert Friedrich Borner · Hamburg, DE
Wolfgang Busselt · Roetgen, DE
Thomas Justel · Witten, DE
Hans Nikol · Aachen, DE
Cornelis Reinder Ronda · Aachen, DE

Key dates

Filing date	Sep 15, 1999
Grant date	May 22, 2001
Priority date	—
Expiry date	Sep 15, 2019

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10S362/80
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

As a white light source, the lighting system (1) has at least three light-emitting diodes (6, 7, 8) for providing visible light at preselected wavelengths. The invention is characterized in that the lighting system (1) is provided with at least one fourth light-emitting diode (9) which, in operation, emits visible light in a further wavelength region, the maximum of the spectral emission of the fourth light-emitting diode (9) lying in the further wavelength region from 575 to 605 nm. Preferably, the further wavelength region ranges from 585 to 600 nm. Preferably, the color rendition of the lighting system (1) is above 60. Preferably, the luminous efficacy of the lighting system (1) is above 30 lm/W, preferably above 40 lm/W. In another preferred embodiment, the color temperature of the lighting system (1) can be adjusted by selectively switching the light-emitting diodes (6, 7, 8, 9).

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.