Long decay phosphors

Patent metadata

Field	Value
Publication number	US-9394480-B2
Application number	US-201313759104-A
Country	US
Kind code	B2
Filing date	Feb 5, 2013
Priority date	Feb 10, 2012
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

The present invention relates to long decay phosphors comprising rare earth activated strontium aluminates and methods for producing them. The phosphors comprise a matrix of the formula Sr 4 Al 14 O 25 comprising europium as an activator and a further rare earth element as a co-activator, wherein the molar ratio of Al/Sr in the starting materials is in the range of 3.1 to less than 3.5 and the ratio of Eu/Sr is in the range of 0.0015 to 0.01. The process for the preparation of a phosphor comprises the steps of milling the starting materials for the synthesis of the phosphor, the starting materials comprising a boron compound selected from boric acid, boric oxide or a borate salt in an amount such that the B/Sr molar ratio is between 0.1 and to 0.3, treating the milled composition with heat, grinding the block material which is obtained through the heat treatment, ball-milling the crushed material, sieving the material, and washing the material with an aqueous solution.

First claim

The invention claimed is:

1. A process for the preparation of a phosphor comprising a matrix of the formula Sr 4 Al 14 O 25 comprising europium and dysprosium,
the starting materials including at least an aluminum compound, a strontium compound, a boron compound, an europium compound and a dysprosium compound, wherein

the range of the molar ratio of Al/Sr is 3.1 to 3.45,
the range of the molar ratio of Eu/Sr is 0.0025 to 0.0075,
the range of the molar ratio of B/Sr is 0.15 to 0.25 and
the range of the molar ratio of Dy/Sr is 0.0075 to 0.015,
the process comprising the steps of
providing a homogeneous mixture of the starting materials for the synthesis of the phosphor by milling the starting materials,
treating the milled composition with heat,
grinding the block material which is obtained through the heat treatment,
ball-milling the ground material, and
sieving the material.

2. The process according to claim 1 , wherein
the range of the molar ratio of Eu/Sr is 0.004 to 0.006,
the range of the molar ratio of B/Sr is 0.15 to 0.20 and
the range of the molar ratio of Dy/Sr is 0.008 to 0.012.

3. The process according to claim 1 , wherein
the molar ratio of Al/Sr is 3.3,
the molar ratio of Eu/Sr is 0.005,
the molar ratio of B/Sr is 0.175 and
the molar ratio of Dy/Sr is 0.01.

4. The process according to claim 1 , wherein the range of the molar ratio of Al/Sr is 3.2 to 3.4.

5. The process according to claim 2 , wherein
the range of the molar ratio of Eu/Sr is 0.004 to 0.006,
the range of the molar ratio of B/Sr is 0.15 to 0.20 and
the range of the molar ratio of Dy/Sr is 0.008 to 0.012.

6. The process according to claim 1 , wherein the range of the molar ratio of Al/Sr is 3.2 to 3.35.

7. The process according to claim 6 , wherein
the range of the molar ratio of Eu/Sr is 0.004 to 0.006,
the range of the molar ratio of B/Sr is 0.15 to 0.20 and
the range of the molar ratio of Dy/Sr is 0.008 to 0.012.

8. A process for the preparation of a phosphor comprising a matrix of the formula Sr 4 Al 14 O 25 comprising europium as an activator and a further rare earth element as a co-activator,
the starting materials including at least an aluminum compound, a strontium compound, a boron compound, an europium compound and a compound of a further rare earth element,
wherein the Al/Sr molar ratio in the starting materials is in the range of 3.2 to 3.4,
the B/Sr molar ratio in the starting materials is in the range of 0.15 to 0.25,
the Eu/Sr molar ratio in the starting materials is in the range of is 0.0025 to 0.0075, and
the Dy/Sr molar ratio in the starting materials is in the range of is 0.0075 to 0.015,

the process comprising the steps of
providing a homogeneous mixture of the starting materials for the synthesis of the phosphor by milling the starting materials,
treating the milled composition with heat,
grinding the block material which is obtained through the heat treatment,
ball-milling the ground material, and
sieving the material.

9. The process according to claim 8 , wherein
the range of the molar ratio of Al/Sr is 3.2 to 3.35,
the range of the molar ratio of Eu/Sr is 0.004 to 0.006,
the range of the molar ratio of B/Sr is 0.15 to 0.20 and
the range of the molar ratio of Dy/Sr is 0.008 to 0.012.

10. The process according to claim 8 , wherein
the molar ratio of Al/Sr is 3.3,
the molar ratio of Eu/Sr is 0.005,
the molar ratio of B/Sr is 0.175 and
the molar ratio of Dy/Sr is 0.01.

Assignees

• Rolex Sa

Inventors

• Berner Detlef
• Güdel Hans U
• Rigot Isabelle
• Girod Romain
• Kenzelmann Christoph

Classifications

• C09K11/7792 Primary

  Aluminates · CPC title