Converter-cooling element assembly with metallic solder connection

Patent metadata

Field	Value
Publication number	US-9982878-B2
Application number	US-201615041471-A
Country	US
Kind code	B2
Filing date	Feb 11, 2016
Priority date	Aug 12, 2013
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

An assembly is provided that includes a ceramic converter for converting light having a first wavelength into light having a second wavelength, a metal-containing reflective coating, and a cooling element. The surface of the ceramic converter is at least partly coated with the metal-containing reflective coating. The coating dissipates the heat from the converter into the cooling element. The cooling element and the metal-containing reflective coating are connected to one another by a metallic solder connection.

First claim

What is claimed is:

1. A converter-cooling element assembly, comprising:
a ceramic converter for at least partial conversion of light having a first wavelength into light having a second wavelength;
a reflective coating comprising metal and glass, wherein the metal is selected from the group consisting of silver, gold, platinum, and alloys thereof, at least portions of a surface of the ceramic converter being directly coated with the reflective coating; and
a heat sink is connected with the reflective coating via a metallic solder connection so that the reflective coating dissipates heat from the ceramic converter into the heat sink, wherein the metallic solder connection comprises tin-containing lead-free solder.

2. The assembly as claimed in claim 1 , further comprising a thermal heat transfer coefficient of at least 25,000 W/m 2 K for at a converter thickness of 200 μm.

3. The assembly as claimed in claim 2 , wherein the thermal resistance is less than 1.5 K/W.

4. The assembly as claimed in claim 1 , wherein the reflective coating comprises silver having a silver content of at least 90 wt %.

5. The assembly as claimed in claim 1 , wherein the reflective coating has a layer thickness from 50 nm to 30 μm.

6. The assembly as claimed in claim 1 , wherein the reflective coating has a glass content from 0.05 to 10 wt %.

7. The assembly as claimed in claim 6 , wherein the glass has a glass transition temperature in a range from 300 to 600° C.

8. The assembly as claimed in claim 6 , wherein the glass has a refractive index n D20 in a range from 1.4 to 2.0.

9. The assembly as claimed in claim 6 , wherein the glass is selected from the group consisting of PbO glass, Bi 2 O 3 glass, ZnO glass, SO 3 glass, and silicate-based glass.

10. The assembly as claimed in claim 6 , wherein the glass is a silicate-based glass having a SiO 2 content of more than 25 wt %.

11. The assembly as claimed in claim 1 , wherein the heat sink exhibits a thermal conductivity of more than 300 W/mK.

12. The assembly as claimed in claim 1 , wherein the heat sink is a heat absorber.

13. The assembly as claimed in claim 1 , wherein the ceramic converter is configured as a transmission arrangement with at least a portion of the reflective coating being positioned on a lateral surface of the ceramic converter.

14. The assembly as claimed in claim 1 , wherein the ceramic converter is configured as a remission arrangement with at least a surface of the ceramic converter that is positionable away from an excitation light source being coated with the reflective coating.

15. The assembly as claimed in claim 1 , further comprising a quality of reflection FOM CIE-cx defined as:

FOM

CIE
-
cx

=

c
x

⁡

(

measured
⁢

⁢
sample

)

-

c
x

⁡

(

Ref

0
⁢
R

)

c
x

⁡

(

Ref
HR

)

-

c
x

⁡

(

Ref

0
⁢
R

)

.

is at least 40%;
wherein c x (measured sample) is a chromaticity coordinate of the ceramic converter provided with the reflective coating as determined in remission for a CIE 1931 standard color system;

c x (Ref HR ) is a chromaticity coordinate of the ceramic converter as determined while applied on an ALANOD mirror having a reflectance of 98%; and c x (Ref HR ) is a chromaticity coordinate of the ceramic converter as determined while applied on a dark background or a light trap.

16. The assembly as claimed in claim 1 , wherein the heat sink comprises a copper-containing core and a coating applied thereto.

17. The assembly as claimed in claim 16 , wherein the coating comprises a nickel-containing coating and/or a gold-containing coating.

18. The assembly as claimed in claim 1 , wherein the reflective coating is a sintered coating.

19. A method for producing a converter-cooling element assembly, comprising the steps of:
providing a ceramic converter with at least one polished surface;
providing paste comprising a metal powder and a glass powder in an organic pasting medium, wherein the metal powder comprises a metal selected from the group consisting of silver, gold, platinum, and alloys thereof;
applying the paste onto at least a portion of the polished surface;
drying the paste;
firing the ceramic converter and having the pasted dried thereon at a firing temperature above 450° C. to form a metal-containing and glass-containing reflective coating; and
soldering a cooling element to the reflective coating with a metallic solder comprising a tin-containing lead-free solder.

20. The method as claimed in claim 19 , wherein the paste comprises 70 to 90 wt % silver powder.

21. The method as claimed in claim 19 , wherein the glass powder has a D50 value in a range from 1 to 5 μm.

22. The method as claimed in claim 19 , wherein the glass powder comprises glass having a glass transition temperature in a range from 300 to 600° C.

23. The method as claimed in claim 19 , wherein the step of applying the paste onto the polished surface comprises printing the paste onto at least the portion of the polished surface.

24. The method as claimed in claim 19 , wherein the step of drying the paste comprises drying at a drying temperature from 150 to 400° C.

25. The method as cl

Assignees

• Schott Ag

Inventors

• Weber Urban
• Hagemann Volker
• Brix Peter
• Kluge Michael

Classifications

• C04B2237/10

  Glass interlayers, e.g. frit or flux · CPC title

• C04B2235/72

  Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics · CPC title

• C04B2237/125

  based on noble metals, e.g. silver · CPC title

• G02B5/0236

  the diffusion taking place within the volume of the element · CPC title

• C04B2235/5436

  micrometer sized, i.e. from 1 to 100 micron · CPC title