Phosphors for down converting ultraviolet light of LEDs to blue-green light

US6466135B1 · kind B1 · utility

Assignee

• General Electric Company · US

Inventors

• Alok Mani Srivastava · San Francisco, US
• Thomas Francis McNulty · Ballston Lake, US
• Holly Ann Comanzo · Niskayuna, US

Key dates

• Filing date: May 15, 2000
• Grant date: Oct 15, 2002
• Expiry date: May 15, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S362/80
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

There is provided a blue-green illumination system, comprising a light emitting diode, and at least one luminescent material having at least two peak emission wavelengths, wherein the emission CIE color coordinates of the at least two peak emission wavelengths are located within an area of a pentagon on a CIE chromaticity diagram, whose corners have the following CIE color coordinates:e) x=0.0137 and y=0.4831;b) x=0.2240 and y=0.3890;c) x=0.2800 and y=0.4500;g) x=0.2879 and y=0.5196; andh) x=0.0108 and y=0.7220.The illumination system may be used as the green light of a traffic signal. The luminescent material may be a blend of (Ba1-xEux)Mg2Al6O27 (&#8220;BAM&#8221;) and (Ba1-xEux)Mg2-yMnyAl16O27 (&#8220;BAMMn&#8221;) phosphors, where 0<x&lE;0.2 and 0<y&lE;0.5.