Luminophores made of doped garnet for pcLEDs

• US 8,088,304 B2
• Filed: 02/13/2008
• Issued: 01/03/2012
• Est. Priority Date: 03/06/2007
• Status: Expired due to Fees

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Winkler, Holger, Vosgroene, Tim, Juestel, Thomas, Moeller, Stephanie
• Primary Examiner(s): Lorengo, Jerry
• Assistant Examiner(s): EDMONDSON, LYNNE RENEE
• Application Number:
  US12/530,075
• Publication Number:
  US 20100084962A1
• Time in Patent Office: 1,420 Days
• Field of Search: 252/301.4 R, 252/301.4 F, 252/301.6 F, 313/467, 313/468, 427/58
• US Class Current: 252/301.4R
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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 2924/12044 OLED
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

The invention relates to phosphors having a garnet structure of the formula I
(Y_a,Gd_b,Lu_c,Se_d,Sm_e,Tb_f,Pr_g,Th_h,Ir_i,Sb_j,Bi_k)_3-x(Al_l,Ga_m)₅O₁₂:Ce_x  (I)

• • where
  • a+b+c+d+e+f+g+h+i+j+k=1
  • l+m=1 and
  • x=0.005 to 0.1,
    and to a process for the preparation of these phosphors, and to the use thereof as conversion phosphors for conversion of the blue or near-UV emission from an LED.

Claims

1. A phosphor having a garnet structure, which is one of the formulae II to IV:

(Y_1-x-yCe_xSb_y)₃Al₅O₁₂ where 0.005≦

x≦

0.1 and 0.001≦

y≦

0.005 

 

(II)

(Y_1-x-yCe_xBi_y)₃Al₅O₁₂ where 0.005≦

x≦

0.1 and 0.001≦

y≦

0.005 

 

(III)

(Y_1-x-yCe_xTh_y)₃Al₅O₁₂ where 0.005≦

x≦

0.1 and 0.001≦

y≦

0.005 

 

(IV).

2. A phosphor according to claim 1, which has a rough surface which carries nanoparticles of SiO₂, TiO₂, Al₂O₃, ZnO, ZrO₂ and/or Y₂O₃ or mixed oxides thereof or particles comprising the phosphor composition.

3. A phosphor according to claim 1, which has a continuous surface coating which consists of SiO₂, TiO₂, Al₂O₃, ZnO, ZrO₂ and/or Y₂O₃ or mixed oxides thereof.

4. A phosphor according to claim 1, which has a porous surface coating which consists of SiO₂, TiO₂, Al₂O₃, ZnO, ZrO₂ and/or Y₂O₃ or mixed oxides thereof or of the phosphor composition.

5. A phosphor according to claim 1, which has a surface that carries functional groups which facilitate chemical bonding to the environment, which are optionally of epoxy or silicone resin.

6. A phosphor according to claim 1, which is obtainable by mixing aluminium-, yttrium- and cerium-containing starting materials with one of Sb-, Bi-, or Th-containing co-dopant by a wet-chemical method and subsequent thermal aftertreatment.

7. A process for preparing a phosphor according to claim 1, comprising

a) preparation of a cerium-activated phosphor which is co-doped with antimony-, bismuth-, or thorium-containing materials from phosphor precursor suspensions or solutions by mixing at least three starting materials Y-, Al-, Ce-containing materials by a wet-chemical method,

b) thermal aftertreatment of the phosphor co-doped with antimony, bismuth, or thorium.

8. A process according to claim 7, wherein the phosphor precursor is prepared in step a) by a wet-chemical method from organic and/or inorganic metal and/or rare-earth salts by a sol-gel method, precipitation method and/or drying method, and/or spray drying.

9. A process according to claim 7, wherein the surface of the phosphor is coated with nanoparticles of SiO₂, TiO₂, Al₂O₃, ZnO, ZrO₂ and/or Y₂O₃ or mixed oxides thereof or with nanoparticles of the phosphor composition.

10. A process according to claim 7, wherein the surface of the phosphor is provided with a continuous coating of SiO₂, TiO₂, Al₂O₃, ZnO, ZrO₂ and/or Y₂O₃ or mixed oxides thereof.

11. A process according to claim 7, wherein the surface of the phosphor is provided with a porous coating of SiO₂, TiO₂, Al₂O₃, ZnO, ZrO₂ and/or Y₂O₃ or mixed oxides thereof or of the phosphor composition.

12. An illumination unit having at least one primary light source whose emission maximum is in the range 410 nm to 530 nm, which is partially or fully converted into longer-wavelength radiation by a phosphor according to claim 1.

13. An illumination unit according to claim 12, wherein the light source is a luminescent indium aluminium gallium nitride, optionally of the formula In_iGa_jAl_kN, where 0≦

i, 0≦

j, 0≦

k, and i+j+k=1.

14. An illumination unit according to claim 12, wherein the light source is a luminescent compound based on ZnO, TCO (transparent conducting oxide), ZnSe or SiC.

15. An illumination unit according to claim 12, wherein the light source is a material based on an organic light-emitting layer.

16. An illumination unit according to claim 12, wherein the light source is a source which exhibits electroluminescence and/or photoluminescence.

17. An illumination unit according to claim 12, wherein the light source is a plasma or discharge source.

18. An illumination unit according to claim 12, wherein the phosphor is arranged directly on the primary light source and/or remote therefrom.

19. An illumination unit according to claim 12, wherein the optical coupling between the phosphor and the primary light source is achieved by a light-conducting arrangement.

20. A method of converting blue or near-UV emission from a luminescent diode, comprising converting by a phosphor according to claim 1.

21. A method of converting primary radiation into a certain colour point by the colour-on-demand concept, comprising converting by a phosphor according to claim 1.

22. A method of converting blue or near-UV emission into visible white radiation, comprising converting by a phosphor according to claim 1.

23. A phosphor according to claim 1, which is of the formula II

(Y_1-x-yCe_xSb_y)₃Al₅O₁₂ where 0.005≦

x≦

0.1 and 0.001≦

y≦

0.005 

 

(II).

24. A phosphor according to claim 1, which is of the formula III

(Y_1-x-yCe_xBi_y)₃Al₅O₁₂ where 0.005≦

x≦

0.1 and 0.001≦

y≦

0.005 

 

(III).

25. A phosphor according to claim 1, which is of the formula IV

(Y_1-x-yCe_xTh_y)₃Al₅O₁₂ where 0.005≦

x≦

0.1 and 0.001≦

y≦

0.005 

 

(IV).