PHOSPHOR PLATES FOR LEDS FROM STRUCTURED FILMS

• US 20100244067A1
• Filed: 10/25/2007
• Published: 09/30/2010
• Est. Priority Date: 11/17/2006
• Status: Abandoned Application

• Current Assignee: Merck Patent Gesellschaft Mit Beschränkter Haftung
• Original Assignee: Merck Patent Gesellschaft Mit Beschränkter Haftung
• Inventors: Petry, Ralf, Winkler, Holger, Ambrosius, Klaus
• Application Number:
  US12/514,937
• Publication Number:
  US 20100244067A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C01P 2004/20 extending in two dimensions, e.g. plate-like
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids, or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint glass constituents C04B2235/36
• CPC Class Codes: C04B 35/62813 Alumina or aluminates
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2996 Glass particles or spheres

Abstract

The invention relates to a phosphor element which is based on natural and/or synthetic flake-form substrates, such as mica, corundum, silica, glass, ZrO₂ or TiO₂, and at least one phosphor, to the production thereof, and to the use thereof as LED conversion phosphor for white LEDs or so-called colour-on-demand applications.

Claims

1. Phosphor element consisting of a phosphor-coated substrate comprising mica, glass, ZrO₂, TiO₂, SiO₂ or Al₂O₃ flakes or mixtures thereof.

5. Phosphor element according to claim 1, characterised in that it is in flake form and has a thickness between 10 μ

m and 5 mm, preferably 20 μ

m to 100 μ

m.

6. Phosphor element according to claim 1, characterised in that the flake-form phosphor element has an aspect ratio of 2:

1 to 400;

1, preferably of 1.5;

1 to 100;

1.

7. Phosphor element according to claim 1, characterised in that the substrate consists of SiO₂ and/or Al₂O₃ flakes.

8. Phosphor element according to claim 1, characterised in that the side surfaces of the phosphor element have been metallised with a light or noble metal.

9. Phosphor element according to claim 1, characterised in that the side of the phosphor element opposite an LED chip has a structured surface.

10. Phosphor element according to claim 1, characterised in that the side of the phosphor element opposite an LED chip has a rough surface which carries nanoparticles of SiO₂, TiO₂, Al₂O₃, ZnO₂, ZrO₂ and/or Y₂O₃ or mixed oxides thereof or particles comprising the phosphor composition.

11. Phosphor element according to claim 1, characterised in that the side of the phosphor element facing an LED chip has a polished surface in accordance with DIN EN ISO 4287.

12. Phosphor element according to claim 1, characterised in that the side of the phosphor element facing an LED chip has a surface which is transparent in the forwards direction to the radiation emitted by the LED.

13. Phosphor element according to claim 1, characterised in that the side of the phosphor element facing an LED chip has a surface which is provided with antireflection properties for the radiation emitted by the LED.

14. Phosphor element according to claim 1, characterised in that the starting materials and the dopant are inorganic and/or organic substances, such as nitrates, carbonates, hydrogen-carbonates, phosphates, carboxylates, alcoholates, acetates, oxalates, halides, sulfates, organometallic compounds, hydroxides and/or oxides of the metals, semimetals, transition metals and/or rare earths which are dissolved and/or suspended in inorganic and/or organic liquids.

15. Phosphor element according to claim 1, characterised in that it consists of at least one of the following phosphor materials:

(Y, Gd, Lu, Sc, Sm, Tb)₃ (Al, Ga)₅O₁₂;

Ce (with or without Pr), (Ca, Sr, Ba)₂SiO₄;

Eu, YSiO₂N;

Ce, Y₂Si₃O₃N₄;

Ce, Gd₂Si₃O₃N₄;

Ce, (Y,Gd,Tb,Lu)₃Al<sub>5−

x</sub>Si_xO<sub>12−

x</sub>N_x;

Ce, BaMgAl₁₀O₁₇;

Eu, SrAl₂O₄;

Eu, Sr₄Al₁₄O₂₅;

Eu, (Ca,Sr,Ba)Si₂N₂O₂;

Eu, SrSiAl₂O₃N₂;

Eu, (Ca,Sr,Ba)₂Si₅N₈;

Eu, CaAlSiN₃;

Eu, zinc/alkaline earth metal orthosilicates, copper/alkaline earth metal orthosilicates, iron/alkaline earth metal orthosilicates, molybdates, tungstates, vanadates, group III nitrides, oxides, in each case individually or mixtures thereof with one or more activator ions, such as Ce, Eu, Mn, Cr and/or Bi.

24. Illumination unit having at least one primary light source whose emission maximum is in the range 240 to 510 nm, where this radiation is converted partially or completely into longer-wavelength radiation by a phosphor element according to claim 1.

25. Illumination unit according to claim 24, 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.

26. Illumination unit according to claim 24, characterised in that the light source is a luminescent material based on ZnO, TCO (transparent conducting oxide), ZnSe or SiC.

27. Illumination unit according to claim 24, characterised in that the light source is a material based on an organic light-emitting layer.

28. Illumination unit according to claim 24, characterised in that the phosphor element is arranged directly on the primary light source and/or remote therefrom.

29. Illumination unit according to claim 24, characterised in that the optical coupling between the phosphor element and the primary light source is achieved by a light-conducting arrangement.

30. Illumination unit according to claim 24, characterised in that the phosphor elements are an arrangement comprising one or more phosphor elements which have identical or different structures.

31. Use of the phosphor element according to claim 1, for conversion of blue or near-UV emission into visible white radiation.

32. Use of the phosphor element according to claim 1, for conversion of the primary radiation into a certain colour point in accordance with the colour-on-demand concept.

2. Phosphor element obtainable by

preparation of a phosphor precursor suspension by mixing at least two starting materials and at least one dopant by wet-chemical methods,

preparation of an aqueous suspension of mica, glass, ZrO₂, TiO₂, SiO₂ or Al₂O₃ flakes or mixtures thereof,

application of the aqueous suspension to a structured support medium with formation of a substrate film,

solidification of the substrate film by drying and separation of the dried substrate film from the support medium,

addition of the phosphor precursor suspension and subsequent addition of a precipitation reagent with formation of a phosphor element precursor,

subsequent thermal treatment of the phosphor element precursor.

3. Phosphor element obtainable by

preparation of a phosphor precursor suspension by mixing at least two starting materials and at least one dopant by wet-chemical methods,

preparation of an aqueous suspension of mica, glass, ZrO₂, TiO₂, SiO₂ or Al₂O₃ flakes or mixtures thereof,

combination of the two suspensions prepared above to give the substrate

application of the substrate to a structured support medium with formation of a substrate film,

solidification of the substrate film by drying and separation of the dried substrate film from the support medium with formation of a phosphor element precursor,

a subsequent thermal treatment of the phosphor element precursor to give the phosphor element obtained.

4. Phosphor element obtainable by

preparation of a phosphor precursor suspension by mixing at least two starting materials and at least one dopant by wet-chemical methods,

application of the phosphor precursor suspension to a structured support medium with formation of a substrate film,

solidification of the substrate film by drying and separation of the dried substrate film from the support medium with formation of a phosphor element precursor,

subsequent thermal treatment of the phosphor element precursor to give the phosphor element obtained.

16. Process for the production of a phosphor element having the following process steps:

a) preparation of a phosphor precursor suspension by mixing at least two starting materials and at least one dopant by wet-chemical methods,

b) preparation of an aqueous suspension of mica, glass, ZrO₂, TiO₂, SiO₂ or Al₂O₃ flakes or mixtures thereof,

c) application of the aqueous suspension prepared under step b to a structured support medium with formation of a substrate film,

d) solidification of the substrate film by drying and separation of the dried substrate film from the support medium,

e) addition of the phosphor precursor suspension prepared under step a and subsequent addition of a precipitation reagent with formation of a phosphor element precursor,

f) subsequent thermal treatment of the phosphor element precursor.

19. Process according to claim 16, characterised in that the phosphor precursor is prepared in step a) by wet-chemical methods from organic and/or inorganic metal, semimetal, transition-metal and/or rare-earth salts by means of sol-gel processes and/or precipitation processes.

20. Process according to claim 16, characterised in that the structured support medium consists of an organic and/or ceramic material, preferably a polyethylene terephthalate film or corundum.

21. Process according to claim 16, characterised in that the subsequent thermal treatment is carried out in one or more steps at temperatures between 700 and 1800°

C., preferably between 900 and 1700°

C.

22. Process according to claim 16, characterised in that the surface of the phosphor element facing away from the LED chip is coated with nanoparticles comprising SiO₂, TiO₂, Al₂O₃, ZnO₂, ZrO₂ and/or Y₂O₃ or mixed oxides thereof or with nanoparticles comprising the phosphor composition.

23. Process according to claim 16, characterised in that a structured surface is produced on the side of the phosphor element facing away from the LED chip.

17. Process for the production of a phosphor element having the following process steps:

a) preparation of a phosphor precursor suspension by mixing at least two starting materials and at least one dopant by wet-chemical methods,

b) preparation of an aqueous suspension of mica, glass, ZrO₂, TiO₂, SiO₂ or Al₂O₃ flakes or mixtures thereof,

c) combination of the suspensions prepared under steps a and b to give the substrate

d) application of the substrate to a structured support medium and formation of a substrate film,

e) solidification of the substrate film by drying and separation of the dried substrate film from the support medium with formation of a phosphor element precursor,

f) subsequent thermal treatment of the phosphor element precursor to give the phosphor element obtained.

18. Process for the production of a phosphor element having the following process steps:

a) preparation of a phosphor precursor suspension by mixing at least two starting materials and at least one dopant by wet-chemical methods,

b) application of the phosphor precursor suspension to a structured support medium and formation of a substrate film,

c) solidification of the substrate film by drying and separation of the dried substrate film from the support medium with formation of a phosphor element precursor,

d) subsequent thermal treatment of the phosphor element precursor to give the phosphor element obtained.