Method of manufacturing fluoride phosphor

• US 9,222,017 B2
• Filed: 07/21/2015
• Issued: 12/29/2015
• Est. Priority Date: 07/03/2013
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Yoshida, Tomokazu
• Primary Examiner(s): Nguyen, Dao H
• Application Number:
  US14/804,337
• Publication Number:
  US 20150322338A1
• Time in Patent Office: 161 Days
• Field of Search: 313/485, 313/503, 313/512, 438/28, 438/29, 438/34, 257/40, 257/79, 257/89, 257/98, 257/E33.001, 257/E33.025, 257/E33.055, 257/E33.06, 257/E51.001, 257/E51.047, 252/301.4, 349/70
• US Class Current: 1/1
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/617 Silicates
• CPC Class Codes: C09K 11/675 with alkali or alkaline earth metals
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source

Abstract

A method of manufacturing a fluoride phosphor includes mixing a first solution which contains at least Mn and F, a second solution which contains at least K and F, and a third solution which contains at least Si and F to form phosphor cores whose composition is represented by a formula K₂[M_1-aMn⁴⁺_aF₆] wherein a satisfies 0<a<0.2, and M includes at least one selected from group-IV elements of Ti, Zr, and Hf and group IVB elements of Si, Ge, Sn. The phosphor cores and a fourth solution containing a reducing agent are mixed to form a surface region on each of the phosphor cores so that a concentration of tetravalent Mn on the surface region of one of the phosphor cores is lower than in an inner region of the one of the phosphor cores.

Claims

1. A method of manufacturing a fluoride phosphor, comprising:

mixing a first solution which contains at least Mn and F, a second solution which contains at least K and F, and a third solution which contains at least Si and F to form phosphor cores whose composition is represented by a formula K₂[M_1-aMn⁴⁺_aF₆] wherein a satisfies 0<

a<

0.2, and M comprises at least one selected from group-IV elements of Ti, Zr, and Hf and group IVB elements of Si, Ge, Sn; and

mixing the phosphor cores and a fourth solution containing a reducing agent to form a surface region on each of the phosphor cores so that a concentration of tetravalent Mn on the surface region of one of the phosphor cores is lower than in an inner region of the one of the phosphor cores.

2. The method according to claim 1,

wherein the reducing agent comprises hydrogen peroxide.

3. The method according to claim 1,

wherein the surface region is formed by mixing the phosphor cores, a fifth solution which contains at least Si and F, a sixth solution which contains at least K and F, and a seventh solution which contains a reducing agent.

4. The method according to claim 3,

wherein the surface region is formed by charging the phosphor cores in an eighth solution which contains at least Si and F, and adding a ninth solution which contains a reducing agent and a tenth solution which contains at least K and F to the eighth solution including the phosphor cores.

5. A method of manufacturing a fluoride phosphor, comprising:

mixing a first solution which contains at least Mn and F, a second solution which contains at least K and F, and a third solution which contains at least Si and F to form phosphor cores whose composition is represented by a formula K₂[M_1-aMn⁴⁺_aF₆] wherein a satisfies 0<

a<

0.2, and M comprises at least one selected from group-IV elements of Ti, Zr, and Hf and group IVB elements of Si, Ge, Sn;

introducing the phosphor cores into the third solution; and

mixing the third solution including the phosphor cores, a fourth solution containing a reducing agent, and the second solution which does not substantially contain tetravalent Mn to form a surface region on each of the phosphor cores such that a concentration of tetravalent Mn in the surface region of one of the phosphor cores is 0.5% or more and 30% or less with respect to a concentration of tetravalent Mn in an inner region of the one of the phosphor cores.

6. The method according to claim 5,

wherein the reducing agent comprises hydrogen peroxide or oxalic acid.

7. The method according to claim 5,

wherein a concentration of tetravalent Mn is approximately uniform in the inner region of the one of the phosphor cores, and is gradually decreased toward a surface in the surface region of the one of the phosphor cores.

8. The method according to claim 5,

wherein M comprises Si or Si and Ge.

9. The method according to claim 5,

wherein the concentration of tetravalent Mn in the surface region of the one of the phosphor cores is 0.5% or more and 25% or less with respect to the concentration of tetravalent Mn in the inner region of the one of the phosphor cores.

10. The method according to claim 5,

wherein the concentration of tetravalent Mn in the surface region of the one of the phosphor cores is 0.5% or more and 20% or less with respect to the concentration of tetravalent Mn in the inner region of the one of the phosphor cores.

11. A method of manufacturing a fluoride phosphor, comprising:

mixing a first solution which contains at least Mn and F, a second solution which contains at least K and F, and a third solution which contains at least Si and F to form phosphor cores whose composition is represented by a formula K₂[M_1-aMn⁴⁺_aF₆] wherein a satisfies 0<

a<

0.2, and M comprises at least one selected from group-IV elements of Ti, Zr, and Hf and group IVB elements of Si, Ge, Sn; and

mixing the phosphor cores and a fourth solution containing a reducing agent.

12. The method according to claim 11, further comprising:

introducing the phosphor cores into the third solution.

13. The method according to claim 11, further comprising:

introducing the phosphor cores into the third solution; and

mixing the third solution including the phosphor cores and the fourth solution.

14. The method according to claim 11, further comprising:

introducing the phosphor cores into the third solution; and

mixing the third solution including the phosphor cores, the fourth solution, and the second solution.

15. The method according to claim 14,

wherein the second solution does not substantially contain tetravalent Mn.