LUMINOPHORES MADE OF DOPED GARNET FOR PCLEDS

• US 20100084962A1
• Filed: 02/13/2008
• Published: 04/08/2010
• Est. Priority Date: 03/06/2007
• Status: Active Grant

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Moeller, Stephanie, Juestel, Thomas, Vosgroene, Tim, Winkler, Holger
• Granted Patent: US 8,088,304 B2
• Time in Patent Office: Days
• US Class Current: 313/484
• 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. Phosphor 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.

2. Phosphor according to claim 1, characterised in that x=0.02 to 0.05.

3. Phosphor according to claim 1, characterised in that the compound of the formula I is a compound selected from the compounds 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)

4. Phosphor according to claim 1, characterised in that it has a structured surface.

5. Phosphor according to claim 1, characterised in that it 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.

6. Phosphor according to claim 1, characterised in that it has a continuous surface coating which consists of SiO₂, TiO₂, Al₂O₃, ZnO, ZrO₂ and/or Y₂O₃ or mixed oxides thereof.

7. Phosphor according to claim 1, characterised in that it 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.

8. Phosphor according to claim 1, characterised in that the surface carries functional groups which facilitate chemical bonding to the environment, preferably consisting of epoxy or silicone resin.

9. Phosphor according to claim 1, obtainable by mixing aluminium-, yttrium- and cerium-containing starting materials with at least one Sb-, Bi-, Ir- and/or Th-containing co-dopant and optionally further Gd-, Lu-, Sc-, Sm-, Tb-, Pr- and/or Ga-containing materials by wet-chemical methods and subsequent thermal aftertreatment.

15. Illumination unit having at least one primary light source whose emission maximum is in the range 410 nm to 530 nm, preferably between 430 nm and 500 nm, where this radiation is partially or fully converted into longer-wavelength radiation by a phosphor according to claim 1.

16. Illumination unit according to claim 15, characterised in that the light source is a luminescent indium aluminium gallium nitride, in particular of the formula In_iGa_jAl_kN, where 0≦

i, 0≦

j, 0≦

k, and i+j+k=1.

17. Illumination unit according to claim 15, characterised in that the light source is a luminescent compound based on ZnO, TCO (transparent conducting oxide), ZnSe or SiC.

18. Illumination unit according to claim 15, characterised in that the light source is a material based on an organic light-emitting layer.

19. Illumination unit according to claim 15, characterised in that the light source is a source which exhibits electroluminescence and/or photoluminescence.

20. Illumination unit according to claim 15, characterised in that the light source is a plasma or discharge source.

21. Illumination unit according to claim 15, characterised in that the phosphor is arranged directly on the primary light source and/or remote therefrom.

22. Illumination unit according to claim 15, characterised in that the optical coupling between the phosphor and the primary light source is achieved by means of a light-conducting arrangement.

23. A method of converting blue or near-UV emission from a luminescent diode, comprising using one phosphor according to claim 1 as conversion phosphor for partial or complete conversion.

24. A method of converting primary radiation into a certain colour point by the colour-on-demand concept, comprising using one phosphor according to claim 1 as conversion phosphor for conversion.

25. A method of converting blue or near-UV emission into visible white radiation, comprising using one phosphor according to claim 1 for the conversion.

10. Process for the preparation of a phosphor having a garnet structure of the formula I, having the following process steps:

a) preparation of a cerium-activated phosphor which is co-doped with antimony-, bismuth-, iridium- and/or thorium-containing materials from phosphor precursor suspensions or solutions by mixing at least three starting materials selected from Y-, Al-, Ce-, Gd-, Lu-, Sc-, Sm-, Tb-, Pr- and/or Ga-containing materials by wet-chemical methods,

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

11. Process according to claim 10, characterised in that the phosphor precursor is prepared in step a) by wet-chemical methods from organic and/or inorganic metal and/or rare-earth salts by means of a sol-gel method, precipitation method and/or drying method, preferably spray drying.

12. Process according to claim 10, characterised in that 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.

13. Process according to claim 10, characterised in that the surface of the phosphor is provided with a continuous coating of SiO₂, TiO₂, Al₂O₃, ZnO, ZrO₂ and/or Y₂O₃ or mixed oxides thereof.

14. Process according to claim 10, characterised in that 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.