Color stable red-emitting phosphors

Patent metadata

Field	Value
Publication number	US-2017145304-A1
Application number	US-201715402606-A
Country	US
Kind code	A1
Filing date	Jan 10, 2017
Priority date	Mar 15, 2013
Publication date	May 25, 2017
Grant date	—

Abstract

A lighting apparatus includes a semiconductor light source in direct contact with a polymer composite comprising a color stable Mn 4+ doped phosphor, wherein the lighting apparatus has a color shift of 1.5 MacAdam ellipses after operating for at least 2,000 hour at a LED current density greater than 2 A/cm 2 , a LED wall-plug efficiency greater than 40%, and a board temperature greater than 25° C.

First claim

1 . A lighting apparatus comprising a semiconductor light source in direct contact with a polymer composite comprising a color stable Mn 4+ doped phosphor, wherein the lighting apparatus has a color shift of ≦2 MacAdam ellipses after operating for 30 minutes at a LED current density greater than 70 A/cm 2 , a LED wall-plug efficiency greater than 18%, and a board temperature greater than 25° C.

2 . A lighting apparatus according to claim 1 , wherein the color stable Mn 4+ doped phosphor is of formula I

wherein
A is Li, Na, K, Rb, Cs, or a combination thereof;
M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof;
x is the absolute value of the charge of the [MF y ] ion; and
y is 5, 6 or 7.

3 . A lighting apparatus according to claim 1 , wherein M is Si, Ge, Sn, Ti, Zr, or a combination thereof.

4 . A lighting apparatus according to claim 1 ,
wherein A is Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Ti, or a combination thereof; and Y is 6.

5 . A lighting apparatus according to claim 1 , wherein the color stable Mn 4+ doped phosphor is K 2 SiF 6 :Mn 4+ .

6 . A color stable Mn 4+ doped phosphor of formula I,

wherein
A is Li, Na, K, Rb, Cs, or a combination thereof;
M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof;
x is the absolute value of the charge of the [MF y ] ion;
y is 5, 6 or 7; and

wherein % intensity loss of the phosphor after exposure to light flux of at least 80 w/cm 2 at a temperature of at least 50° C. for at least 21 hours is ≦4%.

7 . A color stable Mn 4+ doped phosphor according to claim 6 , wherein the % intensity loss of the phosphor is ≦3%.

8 . A color stable Mn 4+ doped phosphor according to claim 6 , wherein the % intensity loss of the phosphor is ≦1.5%.

9 . A color stable Mn 4+ doped phosphor according to claim 6 , of formula K 2 SiF 6 :Mn 4+ .

Assignees

• Gen Electric

Inventors

• Murphy James Edward
• Setlur Anant Achyut
• Garcia Florencio
• Lyons Robert Joseph
• Chowdhury Ashfaqul Islam
• Karkada Nagaveni
• Nammalwar Prasanth Kumar
• Beers William Winder

Classifications

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title

• C09K11/025

  non-luminescent particle coatings or suspension media · CPC title

• C08K3/34

  Silicon-containing compounds · CPC title

• H01L33/502

  Electricity · mapped topic