Narrow band emitting SiAlON phosphor
AssigneeLumileds LLC
InventorsPeter Josef Schmidt, Philipp-Jean Strobel, Volker Weiler, Andreas Tücks
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Abstract
This specification discloses a method of enhancing the stability and performance of Eu2+ doped narrow band red emitting phosphors. The resulting phosphor compositions are characterized by crystallizing in ordered structure variants of the UCr4C4 crystal structure type and having a composition of AE1−xLi3−2yAl1+2y−zSizO4−4y−zN4y+z:EUx(AE=Ca, Sr, Ba; 0<x<0.04, 0≤y<1, 0<z<0.05, y+z≤1). It is believed that the formal substitution (Al,O)+ by (Si,N)+ reduces the concentration of unwanted Eu3+ and thus enhances properties of the phosphor such as stability and conversion efficiency.
Claims17
A luminescent composition of matter characterized by the formula:
- AE1−xLi3−2yAl1+2y−zSizO4−4y−zN4y+z:EUx;
- AE=Ca, Sr, Ba;
- 0<x<0.04;
- 0.4<y<0.6;
- 0<z<0.05;
- and
- a concentration of Si is in a range of a concentration of Eu so that ⅕≤z/x≤4,
- the luminescent composition of matter having a tetragonal crystal structure.
A light emitting device comprising:
- a semiconductor light emitting device;
- and
- a phosphor composition characterized by the formula
- AE1−xLi3−2yAl1+2y−zSizO4−4y−zN4y+z:EUx;
- AE=Ca, Sr, Ba;
- 0<x<0.04;
- 0.4<y<0.6;
- 0<z<0.05;
- and
- a concentration of Si is in a range of a concentration of Eu so that ⅕ ≤z/x≤4;
- the phosphor composition having a tetragonal crystal structure and positioned to absorb light emitted by the semiconductor light emitting device and in response emit light of a longer wavelength.
Dependencies are inferred from the claim text.