LIGHTING DEVICE INCLUDING MULTIPLE ENCAPSULANT MATERIAL LAYERS

• US 20130207141A1
• Filed: 02/13/2012
• Published: 08/15/2013
• Est. Priority Date: 02/13/2012
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Reiherzer, Jesse
• Granted Patent: US 8,946,747 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/00014 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 2933/005 relating to encapsulations
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

A lighting device includes an electrically activated emitter, a first layer that contains a first encapsulant material, and a second layer that contains a second encapsulant material, with a textured interface between the first layer and the second layer. Additional layers including further encapsulant materials and/or lumiphoric materials may be provided. Multiple textured interfaces may be provided. Textured interfaces may be arranged as lenses, including Fresnel lenses.

Claims

1. A lighting device comprising:

at least one electrically activated emitter;

a first layer comprising a first encapsulant material overlying at least a portion of the at least one electrically activated emitter and arranged to receive emissions of the at least one electrically activated emitter; and

a second layer comprising a second encapsulant material overlying at least a portion of the first layer and arranged to receive emissions of the at least one electrically activated emitter, wherein the second encapsulant material is compositionally different from the first encapsulant material;

wherein an interface between the first layer and the second layer comprises at least one of the following features (i) and (ii);

(i) at least one outwardly protruding portion of the first layer that includes at least one protruding portion lateral wall of the first layer arranged in contact with the second layer, wherein the at least one protruding portion of the first layer comprises a height of at least 5 micrometers; and

(ii) at least one recess defined in the first layer that is bounded by at least one recess lateral wall of the first layer arranged in contact with the second layer, wherein the at least one recess defined in the first layer comprises a depth of at least 5 micrometers.

2. A lighting device according to claim 1, wherein the interface between the first layer and the second layer comprises feature (i).

3. A lighting device according to claim 1, wherein the interface between the first layer and the second layer comprises feature (ii).

4. A lighting device according to claim 3, wherein the at least one recess does not penetrate through an entire thickness of the first layer.

5. A lighting device according to claim 1, wherein the interface between the first layer and the second layer comprises a plurality of outwardly protruding portions of the first layer each having a height of at least 5 micrometers or comprises a plurality of recesses defined in the first layer with each recess of the plurality of recesses in the first layer comprising a depth of at least 5 micrometers.

6. A lighting device according to claim 1, comprising at least three outwardly protruding portions of the first layer or comprising at least three recesses defined in the first layer, wherein gaps between adjacent outwardly protruding portions of the at least three outwardly protruding portions, or gaps between adjacent recesses of the at least three recesses, are substantially equal in length.

7. A lighting device according to claim 1, wherein the interface between the first layer and the second layer comprises multiple outwardly protruding portions of the first layer having heights that differ relative to one another, or comprises multiple recesses defined in the first layer having depths that differ relative to one another.

8. A lighting device according to claim 1, wherein the interface between the first layer and the second layer is arranged as a collimating lens, a focusing lens, a diverging lens, and a Fresnel lens.

9. A lighting device according to claim 1, wherein at least one of the first layer and the second layer is devoid of any lumiphoric material.

10. A lighting device according to claim 1, wherein the first layer comprises a material having first index of refraction, and the second layer comprises a material having second index of refraction that is less than the first index of refraction.

11. A lighting device according to claim 1, wherein at least one of the first layer and the second layer comprises at least one light scattering material, and wherein at least one of presence, concentration, amount, average particle size, and distribution of the at least one light scattering material differs between the first layer and the second layer.

12. A lighting device according to claim 1, further comprising a third layer overlying at least a portion of the second layer, wherein the third layer comprise a third encapsulant material that is compositionally different from the second encapsulant material.

13. A lighting device according to claim 12, wherein an interface between the second layer and the third layer comprises at least one of the following features (c) and (d):

(c) at least one outwardly protruding portion of the second layer that includes at least one protruding portion lateral wall of the second layer arranged in contact with the third layer, wherein the at least one protruding portion of the second layer comprises a height of at least 5 micrometers; and

(d) at least one recess defined in the second layer that is bounded by at least one recess lateral wall of the second layer arranged in contact with the third layer, wherein the at least one recess defined in the second layer comprises a depth of at least 5 micrometers.

14. A lighting device according to claim 13, wherein the interface between the second layer and the third layer is arranged as any of a collimating lens, a focusing lens, a diverging lens, and a Fresnel lens.

15. A lighting device according to claim 1, further comprising a lumiphoric material-containing layer arranged between at least portions of first layer and the second layer.

16. A lighting device according to claim 1, wherein the first layer is arranged in contact with the at least one electrically activated emitter or a lumiphor-containing layer contacting the at least one electrically activated emitter.

17. A lighting device according to claim 1, wherein the first layer is spatially segregated from the at least one electrically activated emitter.

18. A lighting device according to claim 1, further comprising at least one lateral bounding element contacting an edge portion of a least one of the first layer and the second layer.

19. A lighting device according to claim 1, wherein the at least one electrically activated emitter comprises at least one electrically activated solid state emitter.

20. A lighting device according to claim 1, wherein the at least one electrically activated solid state emitter is arranged within a reflector cup contacting an edge portion of at least one of the first layer and the second layer.

21. A lighting device according to claim 1, wherein the second layer is continuous in character and is devoid of unconnected segments.

22. A lighting device according to claim 1, wherein the second layer overlies less than an entirety of the first layer.

23. A lighting device according to claim 1, comprising at least one protruding portion lateral wall that is angled in a direction that is non-perpendicular to a light emitting surface of the at least one electrically activated emitter, or comprising at least one recess lateral wall is angled in a direction that is non-perpendicular to a light emitting surface of the at least one electrically activated emitter.

24. A lighting device according to claim 1, wherein the interface between the first layer and the second layer comprises at least one of the following features (A) and (B):

(A) a plurality of outwardly protruding portions of the first layer that are arranged in an array or are concentrically arranged, wherein each outwardly protruding portion includes at least one protruding portion lateral wall of the first layer arranged in contact with the second layer, and wherein each protruding portion of the first layer comprises a height of at least 5 micrometers; and

(B) a plurality of recesses defined in the first layer and that are arranged in an array or are concentrically arranged, wherein each recess is bounded by at least one recess lateral wall of the first layer arranged in contact with the second layer, and wherein the at least one recess defined in the first layer comprises a depth of at least 5 micrometers.

25. A lighting device according to claim 1, wherein the interface between the first layer and the second layer comprises at least one of the following features (a) and (b):

(a) at least one outwardly protruding portion of the first layer that includes at least one protruding portion lateral wall of the first layer arranged in contact with the second layer, wherein the at least one protruding portion of the first layer comprises a height of at least 10 micrometers; and

(b) at least one recess defined in the first layer that is bounded by at least one recess lateral wall of the first layer arranged in contact with the second layer, wherein the at least one recess defined in the first layer comprises a depth of at least 10 micrometers.

26. A lighting device comprising:

at least one electrically activated emitter;

a first layer comprising at least one first encapsulant material arranged to receive light generated by at least one electrically activated emitter; and

a second layer comprising at least one second encapsulant material overlying the first layer and arranged to receive emissions from the first layer, wherein the second encapsulant material is compositionally different from the first encapsulant material;

wherein at least one of (a) at least one surface of the first layer, and (b) a surface of the second layer proximate to the first layer, comprises at least one of the following items (i) to (iv);

(i) at least one outwardly protruding portion comprising a height of at least 5 micrometers;

(ii) at least one recess comprising a depth of at least 5 micrometers;

(iii) at least three features that are regularly spaced relative to one another with substantially equal gaps between adjacent features, wherein the at least three features that are regularly spaced include at least one of recesses and outwardly protruding portions; and

(iv) at least three features comprising regularized height or depth that include at least one of recesses and outwardly protruding portions, including variation in height or depth of less than 20% among the at least three features comprising regularized height or depth.

27. A lighting device according to claim 26, wherein at least one of (a) at least one surface of the first layer, and (b) a surface of the second layer proximate to the first layer, comprises at least one of items (i) and (ii).

28. A lighting device according to claim 26, wherein at least one of (a) at least one surface of the first layer, and (b) a surface of the second layer proximate to the first layer, comprises at least one of items (iii) and (iv).

29. A lighting device according to claim 26, wherein the first layer is arranged in contact with the second layer.

30. A lighting device according to claim 26, wherein the first layer is spatially segregated from the at least one electrically activated emitter.

31. A lighting device according to claim 26, wherein at least one of the first layer and the second layer comprises at least one lumiphoric material.

32. A lighting device according to claim 26, wherein at least one of (a) at least one surface of the first layer, and (b) a surface of the second layer proximate to the first layer, comprises any of a collimating lens, a focusing lens, a diverging lens, and a Fresnel lens.

33. A method for fabricating a lighting device, the method comprising:

depositing a first layer comprising a first encapsulant material over at least a portion of at least one electrically activated emitter, with the first encapsulant material arranged to receive emissions of the at least one electrically activated emitter;

forming at least one of the following items (i) to (iv) in or on the first layer;

(i) at least one outwardly protruding portion of the first layer that includes at least one protruding portion lateral wall of the first layer, wherein the at least one protruding portion of the first layer comprises a height of at least 5 micrometers;

(ii) at least one recess defined in the first layer that is bounded by at least one recess lateral wall of the first layer arranged in contact with the second layer, wherein the at least one recess defined in the first layer comprises a depth of at least 5 micrometers;

(iii) at least three features that are regularly spaced relative to one another with substantially equal gaps between adjacent features, wherein the at least three features include at least one of recesses in the first layer and outwardly protruding portions of the first layer; and

(iv) at least three features comprising regularized height or depth that include at least one of recesses in the first layer and outwardly protruding portions of the first layer, including variation in height or depth of less than 20% among the at least three features; and

depositing a second layer comprising a second encapsulant material over at least a portion of the first layer and arranged to receive emissions of the at least one electrically activated emitter.

34. A method according to claim 33, wherein the forming step comprises forming (i) at least one outwardly protruding portion of the first layer that includes at least one protruding portion lateral wall of the first layer, wherein the at least one protruding portion of the first layer comprises a height of at least 5 micrometers.

35. A method according to claim 33, wherein the forming step comprises forming (ii) at least one recess defined in the first layer that is bounded by at least one recess lateral wall of the first layer arranged in contact with the second layer, wherein the at least one recess defined in the first layer comprises a depth of at least 5 micrometers.

36. A method according to claim 33, wherein the forming step comprises forming (iii) at least three features that are regularly spaced relative to one another with substantially equal gaps between adjacent features, wherein the at least three features include at least one of recesses in the first layer and outwardly protruding portions of the first layer.

37. A method according to claim 33, wherein the forming step comprises forming (iv) at least three features comprising regularized height or depth that include at least one of recesses in the first layer and outwardly protruding portions of the first layer, including variation in height or depth of less than 20% among the at least three features.

38. A method according to claim 33, wherein said forming step comprises applying a compression mold to the first layer, at least partially curing the first layer, and removing the mold, prior to deposition of the second layer.

39. A method according to claim 33, comprising at least partially curing the first layer prior to the forming step.

40. A method according to claim 39, wherein said forming step comprises supplying a stream of pressurized fluid to the first layer to effectuate removal of a portion of the first layer.

41. A method according to claim 39, wherein said forming step comprises supplying to the first layer a chemical reactant adapted to react with the first layer to effectuate removal of a portion of the first layer.

42. A method according to claim 39, wherein said forming step comprises supplying laser energy to the first layer to effectuate removal of a portion of the first layer.

43. A method according to claim 39, wherein said forming step comprises cutting the first layer to effectuate removal of a portion of the first layer.

44. A method according to claim 33, wherein said forming step comprises applying a mask over at least a portion of the first layer and supplying material or energy to the first layer through at least one opening defined in the mask.

45. A method according to claim 33, further comprising mounting the at least one electrically activated emitter to at least one of (i) a substrate and (ii) a reflector, prior to the deposition of the first layer.

46. A method according to claim 33, further comprising depositing a lumiphoric material-containing layer over at least a portion of the first layer prior to the deposition of the second layer.

47. A method according to claim 33, wherein at least one of the first layer and the second layer is applied in liquid form.