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Title: Red phosphors for use in high CRI fluorescent lamps

Abstract

Novel red emitting phosphors for use in fluorescent lamps resulting in superior color rendering index values compared to conventional red phosphors. Also disclosed is a fluorescent lamp including a phosphor layer comprising blends of one or more of a blue phosphor, a blue-green phosphor, a green phosphor and a red a phosphor selected from the group consisting of SrY.sub.2 O.sub.4 :Eu.sup.3+, (Y,Gd)Al.sub.3 B.sub.4 O.sub.12 :Eu.sup.3+, and [(Y.sub.1-x-y-m La.sub.y)Gd.sub.x ]BO.sub.3 :Eu.sub.m wherein y<0.50 and m=0.001-0.3. The phosphor layer can optionally include an additional deep red phosphor and a yellow emitting phosphor. The resulting lamp will exhibit a white light having a color rendering index of 90 or higher with a correlated color temperature of from 2500 to 10000 Kelvin. The use of the disclosed red phosphors in phosphor blends of lamps results in high CRI light sources with increased stability and acceptable lumen maintenance over the course of the lamp life.

Inventors:
; ; ;
Publication Date:
Research Org.:
General Electric Company, Schenectady, NY (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1175550
Patent Number(s):
6,965,193
Application Number:
10/317,423
Assignee:
General Electric Company (Schenectady, NY) OSTI
DOE Contract Number:
FC26-99FT40632
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Srivastava, Alok, Comanzo, Holly, Manivannan, Vankatesan, and Setlur, Anant Achyut. Red phosphors for use in high CRI fluorescent lamps. United States: N. p., 2005. Web.
Srivastava, Alok, Comanzo, Holly, Manivannan, Vankatesan, & Setlur, Anant Achyut. Red phosphors for use in high CRI fluorescent lamps. United States.
Srivastava, Alok, Comanzo, Holly, Manivannan, Vankatesan, and Setlur, Anant Achyut. 2005. "Red phosphors for use in high CRI fluorescent lamps". United States. doi:. https://www.osti.gov/servlets/purl/1175550.
@article{osti_1175550,
title = {Red phosphors for use in high CRI fluorescent lamps},
author = {Srivastava, Alok and Comanzo, Holly and Manivannan, Vankatesan and Setlur, Anant Achyut},
abstractNote = {Novel red emitting phosphors for use in fluorescent lamps resulting in superior color rendering index values compared to conventional red phosphors. Also disclosed is a fluorescent lamp including a phosphor layer comprising blends of one or more of a blue phosphor, a blue-green phosphor, a green phosphor and a red a phosphor selected from the group consisting of SrY.sub.2 O.sub.4 :Eu.sup.3+, (Y,Gd)Al.sub.3 B.sub.4 O.sub.12 :Eu.sup.3+, and [(Y.sub.1-x-y-m La.sub.y)Gd.sub.x ]BO.sub.3 :Eu.sub.m wherein y<0.50 and m=0.001-0.3. The phosphor layer can optionally include an additional deep red phosphor and a yellow emitting phosphor. The resulting lamp will exhibit a white light having a color rendering index of 90 or higher with a correlated color temperature of from 2500 to 10000 Kelvin. The use of the disclosed red phosphors in phosphor blends of lamps results in high CRI light sources with increased stability and acceptable lumen maintenance over the course of the lamp life.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2005,
month =
}

Patent:

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  • A phosphor blend comprises at least two phosphors each selected from one of the groups of phosphors that absorb UV electromagnetic radiation and emit in a region of visible light. The phosphor blend can be applied to a discharge gas radiation source to produce light sources having high color rendering index. A phosphor blend is advantageously includes the phosphor (Tb,Y,LuLa,Gd).sub.x(Al,Ga).sub.yO.sub.12:Ce.sup.3+, wherein x is in the range from about 2.8 to and including 3 and y is in the range from about 4 to and including 5.
  • A phosphor blend comprises at least two phosphors each selected from one of the groups of phosphors that absorb UV electromagnetic radiation and emit in a region of visible light. The phosphor blend can be applied to a discharge gas radiation source to produce light sources having high color rendering index. A phosphor blend is advantageously includes the phosphor (Tb,Y,LuLa,Gd).sub.x(Al,Ga).sub.yO.sub.12:Ce.sup.3+, wherein x is in the range from about 2.8 to and including 3 and y is in the range from about 4 to and including 5.
  • A phosphor, a phosphor blend including the phosphor, a phosphor prepared by a process, and a lighting apparatus including the phosphor blend are disclosed. The phosphor has the formula (Ca.sub.1-p-qCe.sub.pK.sub.q).sub.xSc.sub.y(Si.sub.1-rGa.sub.r).sub.zO.su- b.12+.delta. or derived from a process followed using disclosed amounts of reactants. In the formula, (0<p.ltoreq.0.06); 0.ltoreq.q.ltoreq.0.06; 0.ltoreq.r.ltoreq.0.2; and -0.1.ltoreq..delta..ltoreq.0.4. In one embodiment, 3<x.ltoreq.3.1; 2.ltoreq.y.ltoreq.2.15; and 3.ltoreq.z.ltoreq.3.2. Similarly, in another embodiment, 3.ltoreq.x.ltoreq.3.1; 2<y.ltoreq.2.15; and 2.8.ltoreq.z.ltoreq.3.2.
  • An LED lamp includes a light source configured to emit radiation with a peak intensity at a wavelength between about 250 nm and about 550 nm; and a phosphor composition configured to be radiationally coupled to the light source. The phosphor composition includes particles of a phosphor of formula I, said particles having a coating composition disposed on surfaces thereof; ((Sr.sub.1-zM.sub.z).sub.1-(x+w)A.sub.wCe.sub.x).sub.3(Al.sub.1-ySi.sub.y-)O.sub.4+y+3(x-w)F.sub.1-y-3(x-w) I wherein the coating composition comprises a material selected from aluminum oxide, magnesium oxide, calcium oxide, barium oxide, strontium oxide, zinc oxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, strontium hydroxide, zinc hydroxide, aluminum phosphate, magnesium phosphate, calciummore » phosphate, barium phosphate, strontium phosphate, and combinations thereof; and A is Li, NA, K, or Rb, or a combination thereof; M is Ca, Ba, Mg, Zn, or a combination thereof; and 0<x.ltoreq.1.10, 0.ltoreq.y.ltoreq.0.5, 0.ltoreq.z.ltoreq.0.5, 0.ltoreq.x.ltoreq.x.« less
  • A CFL ballast includes complementary-type switching devices connected in series with their gates connected together at a control node. The switching devices supply a resonant tank circuit which is tuned to a frequency near, but slightly lower than, the resonant frequency of a resonant control circuit. As a result, the tank circuit restarts oscillations immediately following each zero crossing of the bus voltage. Such rapid restarts avoid undesirable flickering while maintaining the operational advantages and high efficacy of the CFL ballast. 4 figs.