Solid state lamp using light emitting strips
A solid state lamp includes a connector and a bulb portion with multiple strips.
1. A solid state lamp comprising:
a base configured to electrically connect the solid state lamp to a power source, the base defining an axis;
an envelope extending along the axis; and
a strip inside the envelope, the strip comprising:
a substrate;
a plurality of spaced-apart light-emitting diode (LED) unpackaged dies disposed on a top surface of the substrate;
conductors arranged to provide electrical power to the LED unpackaged dies; and
a wavelength-conversion material optically coupled with the LED unpackaged dies,
wherein the substrate transmits at least some light from the top surface to the bottom surface, and
wherein the top surface faces a first side of the strip and a bottom surface of the substrate opposite the top surface faces a second side of the strip, and the strip outputs first light from the first side having a first spectral power distribution (SPD) and outputs second light from the second side having a second SPD different from the first SPD.
2. The solid state lamp of claim 1 , further comprising an encapsulant encapsulating the LED unpackaged dies on the top surface of the substrate, the encapsulant comprising the wavelength-conversion material.
3. The solid state lamp of claim 2 , wherein a thickness of the encapsulant varies with distance from the LED dies.
4. The solid state lamp of claim 2 , wherein the encapsulant on the top surface of the substrate provides a first light emission surface through which the strip outputs a first intensity of light during operation, and a side of the strip opposite the first light emission surface provides a second light emission surface through which the strip outputs a second intensity of light during operation, and the first intensity of light is higher than the second intensity of light.
5. The solid state lamp of claim 2 , wherein the encapsulant is a solid encapsulant.
6. The solid state lamp of claim 2 , wherein the substrate comprises side surfaces between the top surface and the opposing bottom surface and portions of the side surfaces are free of the encapsulant.
7. The solid state lamp of claim 2 , wherein the encapsulant provides an outside surface of the strip.
8. The solid state lamp of claim 1 , further comprising a plurality of tiles comprising the wavelength-conversion material, each tile being arranged to receive light emitted from a corresponding one of the spaced-apart LED unpackaged dies.
9. The solid state lamp of claim 8 , wherein each of the spaced-apart LED unpackaged die is arranged between a corresponding one of the tiles and substrate, each tile having a dimension the same as a dimension of the corresponding LED unpackaged die parallel to the top surface of the substrate.
10. The solid state lamp of claim 8 , wherein each of the spaced-apart LED unpackaged die is arranged between a corresponding one of the tiles and substrate, each tile having an area the same as or larger than an area of the corresponding LED unpackaged die parallel to the top surface of the substrate.
11. The solid state lamp of claim 10 , wherein the tiles are arranged side by side over a top surface of the LED unpackaged dies.
12. The solid state lamp of claim 8 , wherein the tiles are in contact with the LED unpackaged dies.
13. The solid state lamp of claim 1 , wherein an intensity of light emitted in a first direction above the top surface of the strip differs from an intensity of light emitted below the bottom surface in a second direction opposite the first direction.
14. The solid state lamp of claim 1 , wherein each of the LED unpackaged dies comprises a reflector.
15. The solid state lamp of claim 14 , wherein the reflector is arranged perpendicular to the top surface of the substrate and configured to reflect light generated within the corresponding LED unpackaged die.
16. The solid state lamp of claim 14 , wherein the reflector is arranged parallel to the top surface of the substrate and configured to reflect light generated within the corresponding LED unpackaged die.
17. The solid state lamp of claim 16 , wherein each of the LED unpackaged dies is arranged with the reflector adjacent the substrate.
18. The solid state lamp of claim 14 , wherein the reflector is arranged to reflect light generated within the corresponding LED unpackaged die in directions away from the top surface of the substrate.
19. The solid state lamp of claim 14 , wherein the reflector comprises an electrode of the corresponding LED unpackaged die.
20. The solid state lamp of claim 1 , wherein the base is a first base arranged at the first end of the strip and the solid state lamp further comprises a second base arranged at the second end of the strip, and the first and second base electrically connect the solid state lamp to the power source.
21. The solid state lamp of claim 20 , wherein the envelope is an elongate tubular envelope.
22. The solid state lamp of claim 1 , wherein the wavelength-conversion material comprises a mixture of a phosphor and a binder.
23. The solid state lamp of claim 22 , wherein the binder comprises a silicone.
24. The solid state lamp of claim 22 , wherein the mixture is in contact with the LED unpackaged dies and the top surface of the substrate between the LED unpackaged dies.
25. The solid state lamp of claim 22 , wherein a density of the phosphor varies within the mixture of the phosphor and the binder.
26. The solid state lamp of claim 1 , wherein the LED unpackaged dies are flip-chip LED dies.
27. The solid state lamp of claim 1 , wherein the LED unpackaged dies each have a wire bond pad on a face of the corresponding LED unpackaged die that is facing away from the top surface of the substrate.
28. The solid state lamp of claim 1 , wherein each of the LED unpackaged dies has two electrodes on a face of the corresponding LED unpackaged die facing away from the top surface of the substrate.
29. The solid state lamp of claim 1 , further comprising a phosphor layer disposed on the bottom surface of the substrate.
30. The solid state lamp of claim 29 , wherein a composition of the phosphor layer on the bottom surface of the substrate is different from a composition of the wavelength-conversion material.
31. The solid state lamp of claim 1 , wherein the transmissive substrate is a transparent substrate.
32. The solid state lamp of claim 1 , wherein the strip is further supported by the envelope.
33. The solid state lamp of claim 32 , wherein the strip comprises terminals coupled to the support structure.
34. The solid state lamp of claim 32 , wherein the strip is supported by leads.
35. The solid state lamp of claim 34 , wherein the leads comprise wires.
36. The solid state lamp of claim 34 , wherein the power source provides a mains voltage and the solid state lamp is configured to provide the mains voltage directly to the strip.
37. The solid state lamp of claim 1 , further comprising a support structure, wherein the strip is supported by the support structure.
38. The solid state lamp of claim 37 , wherein the support structure is electrically connected to the strip.
39. The solid state lamp of claim 37 , wherein the support structure comprises a stiff rod.
40. The solid state lamp of claim 37 , wherein the support structure comprises wires.
41. The solid state lamp of claim 40 , wherein the strip is a helical strip.
42. The solid state lamp of claim 41 , wherein the helical strip is a flexible helical strip.
43. The solid state lamp of claim 40 , wherein the wires comprise a first wire connected to the first end of the strip and a second wire connected to the second end of the strip.
44. The solid state lamp of claim 43 , wherein the first portion of the support structure is disposed proximate the base and the second portion of the support structure is disposed distal of the base.
45. The solid state lamp of claim 1 , wherein the strip is a free-standing strip supported only at the first end and extends from the base, and the base has a connection location configured to receive the free-standing strip at the first end.
46. The solid state lamp of claim 45 , wherein the free-standing strip comprises a plug-in connector configured to electrically connect and support the free-standing strip.
47. The solid state lamp of claim 1 , wherein the strip further comprises additional electrical components and the LED unpackaged dies are electrically connected with the additional electrical components.
48. The solid state lamp of claim 1 , wherein the LED unpackaged dies are arranged in multiple rows along the substrate and the LED unpackaged dies in the strip are electrically connected in series.
49. The solid state lamp of claim 1 , wherein the LED unpackaged dies are arranged between some of the electrical conductors and the substrate.
50. The solid state lamp of claim 1 , further comprising multiple of said strips arranged around the axis.
51. The solid state lamp of claim 50 , wherein the first sides of the strips face outward away from the axis.
52. The solid state lamp of claim 50 , wherein the strips are inclined relative to the axis.
53. The solid state lamp of claim 50 , wherein two of the strips are electrically connected in series.
54. The solid state lamp of claim 50 , wherein the strips output light having different color temperatures and are controlled by a driver to output a combined light over a range of color temperatures.
55. The solid state lamp of claim 54 , wherein the combined light tracks a color temperature of an incandescent bulb during dimming.
56. The solid state lamp of claim 1 , wherein the LED unpackaged dies are evenly spaced.
57. The solid state lamp of claim 1 , wherein the LED unpackaged dies comprise first LED unpackaged dies associated with a first bin and second LED unpackaged dies associated with a second bin different from the first bin.
58. The solid state lamp of claim 57 , wherein the first LED unpackaged dies have a SPD with a first peak wavelength and the second LED unpackaged dies have a SPD with a second peak wavelength that differs from the first peak wavelength by 4 nm or more.
59. The solid state lamp of claim 58 , wherein second peak wavelength differs from the first peak wavelength by 10 nm.
60. The solid state lamp of claim 1 , wherein the envelope further comprises a reflective portion and an exit portion, the reflective portion surrounding the strip and configured to reflect light from the strip toward the exit portion, and the solid state lamp is a directional solid state lamp that outputs light from the exit portion with a beam distribution narrower than a hemispherical distribution.
61. The solid state lamp of claim 60 , wherein the reflective portion comprises multiple facets.
62. The solid state lamp of claim 60 , wherein the solid state lamp is configured as a MR16, R30 or PAR38 lamp.
63. The solid state lamp of claim 60 , wherein the reflective portion is a diffuse reflective portion.
64. The solid state lamp of claim 60 , wherein the exit portion extends perpendicular to the axis of the base.
65. The solid state lamp of claim 60 , wherein the exit portion is a curved exit portion.
66. The solid state lamp of claim 60 , wherein the exit portion is a diffuse transmissive exit portion.
67. The solid state lamp of claim 60 , wherein the exit portion comprises a lens.
68. The solid state lamp of claim 60 , further comprising a diffuser disposed at the exit portion.
69. The solid state lamp of claim 1 , wherein the envelope is a clear envelope.
70. The solid state lamp of claim 1 , wherein the envelope comprises a phosphor.
71. The solid state lamp of claim 1 , wherein the envelope is selected from multiple different envelopes configured to provide different light output patterns, and the solid state lamp is configured to couple with the different envelopes to provide corresponding light output patterns.
72. The solid state lamp of claim 71 , wherein the envelope is a replaceable envelope.
73. The solid state lamp of claim 1 , wherein the envelope is a bulb-shaped envelope.
74. The solid state lamp of claim 1 , wherein the envelope comprises perforations.
75. The solid state lamp of claim 1 , wherein the substrate has a thickness between 0.025 mm and 3 mm.
76. The solid state lamp of claim 1 , wherein the strip has a thickness of 1 cm or less.
77. The solid state lamp of claim 1 , wherein the strip is 1 mm to 2 mm thick.
78. The solid state lamp of claim 1 , wherein the strip is less than 5 mm wide.
79. The solid state lamp of claim 1 , wherein the strip is between 1 inch and 6 inches long.
80. The solid state lamp of claim 1 , wherein a light emitting portion of the solid state lamp has a dimension in a range from 2 inches to 4 inches.
81. The solid state lamp of claim 1 , wherein the strip outputs the first light and the second light into different illumination distributions.
82. The solid state lamp of claim 1 , further comprising a connector attached to the strip and covering a portion of a side surface of the substrate, the connector providing an electrical connection to the strip.