Light emitting devices and components having improved chemical resistance and related methods
Light emitting devices and components having excellent chemical resistance and related methods are disclosed. In one embodiment, a component of a light emitting device can include a silver (Ag) portion, which can be silver on a substrate, and a protective layer disposed over the Ag portion. The protective layer can at least partially include an inorganic material for increasing the chemical resistance of the Ag portion.
1. A light emitting device comprising:
a substrate comprising a leadframe with an electrical element having a silver (Ag) portion;
a body arranged about the leadframe, the body forming a cavity such that the electrical element extends within the body and is disposed on a floor of the cavity;
a protective layer at least partially disposed over the Ag portion of the electrical element such that a portion of the protective layer is arranged between the electrical element and the body, the protective layer at least partially comprising an inorganic material for increasing chemical resistance of the Ag portion, wherein the inorganic material contains some organic component, wherein the protective layer comprises a substantially uniform thickness over the Ag portion, and wherein the protective layer at least partially comprises a silicon (Si)-containing spin-on glass material;
a light-emitting diode (LED) chip on a surface of the substrate at the floor of the cavity, wherein the LED chip is electrically coupled to the electrical element by a wire bond, and at least a portion of the wire bond extends through the protective layer; and
a filling material containing a phosphor material disposed therein, wherein the filling material is disposed above and/or below the protective layer.
2. The light emitting device of claim 1 , wherein the spin-on glass material comprises a glass family selected from the group consisting of a silicate family, a phosphosilicate family, a siloxane family, a methylsiloxane family, a silsesquioxane family, and a dopant-containing variation of one of these families.
3. The light emitting device of claim 1 , wherein the protective layer comprises a thickness from approximately 50 nm to approximately 100 μm.
4. The light emitting device of claim 3 , wherein the protective layer comprises a thickness from approximately 50 nm to approximately 100 nm.
5. The light emitting device of claim 3 , wherein the protective layer comprises a thickness from approximately 100 nm to approximately 500 nm.
6. The light emitting device of claim 3 , wherein the protective layer comprises a thickness from approximately 0.5 μm to approximately 20 μm.
7. The light emitting device of claim 1 , wherein the protective layer is directly disposed over and on the substrate.
8. The light emitting device of claim 1 , wherein the LED chip is at least partially disposed between the protective layer and the substrate.
9. The light emitting device of claim 1 , wherein an encapsulant is at least partially disposed between the protective layer and the substrate.
10. The light emitting device of claim 1 , wherein a layer of phosphor containing material is disposed between the protective layer and the substrate.
11. The light emitting device of claim 1 , wherein a layer of material is disposed between the protective layer and the substrate.
12. The light emitting device of claim 1 , wherein the substrate comprises two or more protective layers disposed over the substrate, where each protective layer at least partially comprises the inorganic material.
13. The light emitting device of claim 1 , wherein the light emitting device forms a surface mount device (SMD) type light emitting device.
14. A method of providing a light emitting device, the method comprising:
providing a substrate comprising a leadframe with an electrical element having a silver (Ag) portion;
providing a body arranged about the leadframe, the body forming a cavity such that the electrical element extends within the body and is disposed on a floor of the cavity;
applying a first layer on the Ag portion;
applying a protective layer over the first layer and the Ag portion of the electrical element such that a portion of the protective layer is arranged between the electrical element and the body, the protective layer at least partially comprising an inorganic material for increasing chemical resistance of the Ag portion, wherein the inorganic material contains some organic component, wherein the protective layer comprises a substantially uniform thickness over the Ag portion, and wherein the protective layer at least partially comprises a silicon (Si)-containing spin-on glass material;
providing a light-emitting diode (LED) chip on a surface of the substrate at the floor of the cavity, and electrically coupling the LED chip to the electrical element by a wire bond, wherein at least a portion of the wire bond extends through the protective layer; and
applying a filling material to the substrate, the filling material containing a phosphor material disposed therein, wherein the filling material is disposed above and/or below the protective layer.
15. The method of claim 14 , wherein applying the spin-on glass material comprises applying a glass family selected from the group consisting of a silicate family, a phosphosilicate family, a siloxane family, a methylsiloxane family, a silsesquioxane family, and a dopant-containing variation of one of these families.
16. The method of claim 14 , wherein applying the protective layer comprises using a spin-on, brushing, painting, dipping, plating, spraying, screen-printing, a physical vapor deposition (PVD), or a chemical vapor deposition (CVD) technique.
17. The method of claim 14 , wherein applying the protective layer comprises applying a layer having a thickness from approximately 50 nm to approximately 100 μm.
18. The method of claim 17 , wherein applying the protective layer comprises applying a layer having a thickness from approximately 50 nm to approximately 100 nm.
19. The method of claim 17 , wherein applying the protective layer comprises applying a layer having a thickness from approximately 100 nm to approximately 500 nm.
20. The method of claim 17 , wherein applying the protective layer comprises applying a layer having a thickness from approximately 0.5 μm to approximately 20 μm.
21. The method of claim 14 , further comprising curing the protective layer.
22. The method of claim 21 , wherein curing the protective layer comprises curing at a temperature of approximately 300° C. or less.
23. The method of claim 21 , wherein curing the protective layer comprises curing at a temperature of approximately 250° C. or less.
24. The method of claim 21 , wherein curing the protective layer comprises curing at a temperature of approximately 200° C. or less.
25. The method of claim 21 , wherein curing the protective layer comprises curing at a temperature of approximately 150° C. or less.
26. The method of claim 21 , wherein curing the protective layer comprises curing at a temperature of approximately 100° C. or less.
27. The method of claim 14 , further comprising preparing a surface of the Ag portion or the protective layer via sandblasting, plasma etching, brushing, lapping, sanding, burnishing, or grinding.
28. The method of claim 14 , further comprising chemically treating a surface of the Ag portion or the protective layer via chemical etching, applying solvents, applying organic solvents, applying acids, applying bases, vapor degreasing, or priming.
29. The method of claim 14 , further comprising thermally treating a surface of the Ag portion or the protective layer via prebaking or preheating.
30. The method of claim 14 , wherein the protective layer is applied prior to molding the body of the light emitting device.
31. The method of claim 14 , wherein the protective layer is applied prior to applying encapsulation to the light emitting device.
32. The method of claim 14 , wherein the protective layer is applied after applying encapsulation to the light emitting device.
33. The light emitting device of claim 1 , wherein the filling material defines a light emitting device emission area and the LED chip is electrically coupled to the electrical element outside of the light emitting device emission area.
34. The method of claim 14 , wherein the first layer comprises an adhesion layer between the protective layer and the Ag portion of the electrical element.
35. The method of claim 14 , wherein the first layer comprises an oxide layer.
36. The method of claim 14 , wherein the first layer comprises another phosphor material.