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

US6555958B1 · 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
• Dan Darcy Doxsee · Sagamore Hills, US

Key dates

• Filing date: May 15, 2000
• Grant date: Apr 29, 2003
• Expiry date: May 15, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S502/509

Abstract

There is provided a blue-green illumination system, comprising a light emitting diode, and a luminescent material having emission CIE color coordinates located within an area of a of a pentagon on a CIE chromaticity diagram, whose corners have the following CIE color coordinates:i) x=0.0137 and y=0.4831;ii) x=0.2240 and y=0.3890;iii) x=0.2800 and y=0.4500;iv) x=0.2879 and y=0.5196; andv) x=0.0108 and y=0.7220.The light emitting diode may be a UV LED and the luminescent material may be a Ba2SiO4:Eu2+ phosphor, a Ba2(Mg,Zn)Si2O7:Eu2+ phosphor and/or a Ba2Al2O4:Eu2+ phosphor. The illumination system may be used as the green light of a traffic light or an automotive display.