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 configured to transmit light, the envelope extending along the axis; and
multiple strips inside the envelope, each of the strips extending from a first end to a second end opposite the first end, each of the strips comprising:
a light-transmissive substrate layer of a dielectric material, the substrate layer having a top surface and an opposing bottom surface continuously extending from the first end to the second end;
a plurality of bare light-emitting diode (LED) dies arranged along the top surface of the substrate layer between the first and second ends of the strip;
conductors arranged to provide electrical power to the bare LED dies; and
a wavelength-converting encapsulant encapsulating the bare LED dies; and
a light-diffusing layer arranged over the encapsulant;
multiple connectors mechanically attached to the strips, the connectors providing electrical connections for the strips; and
a driver configured to receive electrical power from the base and control electrical power provided to the bare LED dies; wherein each of the strips is individually distinct and spaced apart from the other strips.
2. The solid-state lamp of claim 1 , wherein the light-diffusing layer has a pattern on an outside surface of the strip that diffuses light.
3. The solid-state lamp of claim 1 , further comprising a support structure extending along the axis, the support structure comprising a wire frame providing electrical power and support to the first and second ends of the strips, the wire frame comprising a first portion attached to the first ends of the strips and a second portion attached to the second ends of the strips.
4. The solid-state lamp of claim 3 , wherein, in each of the strips, the substrate layer comprises a side surface between the top surface and the bottom surface, the side surface including long side surfaces extending from the first end to the second end, and short side surfaces at the first and second ends of the strip, the corresponding connector covering a portion of the long side surfaces of the substrate layer.
5. The solid-state lamp of claim 4 , wherein each of the bare LED dies has a reflector arranged perpendicular to the top surface of the substrate layer.
6. The solid-state lamp of claim 4 , wherein each of the bare LED dies has a reflector arranged parallel to the top surface of the substrate layer.
7. The solid-state lamp of claim 6 , wherein the reflector is arranged to reflect light from within the corresponding bare LED die in directions away from the top surface of the substrate layer.
8. The solid-state lamp of claim 6 , wherein the reflector comprises an electrode of the corresponding bare LED die.
9. The solid-state lamp of claim 4 , wherein each of the bare LED dies are flip-chip LED dies.
10. The solid-state lamp of claim 4 , wherein each of the bare LED dies has a wire bond pad on a face of the corresponding bare LED die facing away from the top surface of the substrate layer.
11. The solid-state lamp of claim 4 , wherein each of the bare LED dies has a pair of electrodes on a face of the corresponding bare LED die facing away from the top surface of the substrate layer.
12. The solid-state lamp of claim 4 , 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.
13. The solid-state lamp of claim 12 , wherein the envelope is a replaceable envelope.
14. The solid-state lamp of claim 4 , wherein the envelope is a bulb-shaped envelope.
15. The solid-state lamp of claim 4 , wherein the encapsulant comprises a mixture of a phosphor and a binder.
16. The solid-state lamp of claim 15 , wherein the binder comprises a silicone.
17. The solid-state lamp of claim 15 , wherein the mixture of a phosphor and a binder is in contact with the bare LED dies.
18. The solid-state lamp of claim 17 , wherein the mixture of a phosphor and a binder is in contact with the top surface of the substrate layer between the bare LED dies.
19. The solid-state lamp of claim 15 , wherein the bare LED dies emit light with a first efficacy when driven at a first drive current density and emit light with a second efficacy when driven at a second drive current density, the second drive current density being higher than the first drive current density but the second efficacy being lower than the first efficacy, and the driver is configured to drive the bare LED dies at the first drive current density, wherein the first efficacy is up to 30% higher than the second efficacy.
20. The solid-state lamp of claim 15 , wherein a density of the phosphor varies within the mixture of the phosphor and the binder.
21. The solid-state lamp of claim 15 , wherein a thickness of the encapsulant varies along the top surface of the substrate layer between the first and second ends of the strip.
22. The solid-state lamp of claim 15 , further comprising a phosphor layer disposed on the bottom surface of the substrate layer.
23. The solid-state lamp of claim 15 , wherein portions of the long side surfaces are free of the encapsulant.
24. The solid-state lamp of claim 4 , wherein the encapsulant on the top surface of the substrate layer 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.
25. The solid state lamp of claim 24 , wherein the first light emission surface is a primary light emission surface and the second light emission surface is a light leakage surface.
26. The solid-state lamp of claim 4 , wherein the top surface faces a first side of the strip and a bottom surface of the substrate layer 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.
27. The solid-state lamp of claim 4 , wherein the substrate layer is a transparent substrate layer.
28. The solid-state lamp of claim 4 , wherein the strips are further supported by the envelope.
29. The solid-state lamp of claim 4 , wherein the envelope is a clear envelope.
30. The solid-state lamp of claim 4 , wherein the envelope comprises perforations.
31. The solid-state lamp of claim 4 , wherein each of the strips is supported by leads.
32. The solid-state lamp of claim 31 , wherein the leads comprise wires.
33. The solid-state lamp of claim 4 , wherein each of the strips is supported by a first lead and a second lead.
34. The solid-state lamp of claim 33 , wherein the first lead is arranged at the first end of the strip and the second lead is arranged at the second end of the strip.
35. The solid-state lamp of claim 33 , wherein the first and second leads are connected to the support structure.
36. The solid-state lamp of claim 4 , wherein an end conductor of each of the strips comprises a terminal pad arranged on the top surface of the substrate layer electrically connected to the corresponding connector.
37. The solid-state lamp of claim 36 , wherein the terminal pad is a first terminal pad and the strip comprises a second terminal pad electrically connected to the base.
38. The solid-state lamp of claim 4 , wherein the power source provides a mains voltage and the solid-state lamp is configured to provide the mains voltage directly to the strips.
39. The solid-state lamp of claim 4 , wherein the strips extend along the axis of the base.
40. The solid-state lamp of claim 4 , wherein the substrate layer has a thickness between 0.025 mm and 3 mm.
41. The solid-state lamp of claim 4 , wherein the strips have a thickness of 1 cm or less.
42. The solid-state lamp of claim 4 , wherein the strips are 1 mm to 2 mm thick.
43. The solid-state lamp of claim 4 , wherein the strips have a width less than 5 mm.
44. The solid-state lamp of claim 4 , wherein the strips have a length between 1 inch and 6 inches.
45. The solid-state lamp of claim 4 , wherein a light emitting portion of the solid-state lamp has a dimension in a range from 2 inches to 4 inches.
46. The solid-state lamp of claim 4 , wherein the strips further comprise additional electrical components and the bare LED dies are electrically connected with the additional electrical components.
47. The solid-state lamp of claim 4 , wherein the bare LED dies are arranged in multiple rows in each of the strips.
48. The solid-state lamp of claim 47 , wherein the bare LED dies in each of the strips are electrically connected in series.
49. The solid-state lamp of claim 4 , wherein in each of the strips, the bare LED dies are arranged between some of the electrical conductors and the substrate layer.
50. The solid-state lamp of claim 4 , wherein the bare LED dies in the strips are evenly spaced.
51. The solid-state lamp of claim 4 , wherein the bare LED dies comprise first bare LED dies associated with a first bin and second bare LED dies associated with a second bin different from the first bin.
52. The solid-state lamp of claim 51 , wherein the first bare LED dies have a spectral power distribution (SPD) with a first peak wavelength and the second bare LED dies have a SPD with a second peak wavelength that differs from the first peak wavelength by 4 nm or more.
53. The solid-state lamp of claim 52 , wherein second peak wavelength differs from the first peak wavelength by 10 nm.
54. The solid-state lamp of claim 4 , wherein the envelope comprises a phosphor.
55. The solid-state lamp of claim 4 , wherein the encapsulant is a solid encapsulant.
56. The solid-state lamp of claim 4 , wherein the strips include a total number of 144 or more bare LED dies.
57. The solid-state lamp of claim 4 , wherein the strips output a total amount of light of 600 lumens to 1000 lumens.
58. The solid-state lamp of claim 57 , wherein the strips output a total amount of light of 800 lumens to 900 lumens.
59. The solid-state lamp of claim 4 , wherein the strips are oriented so that their respective top surfaces face different directions.
60. The solid-state lamp of claim 4 , wherein the strips output light having different color temperatures and are controlled by the driver to output a combined light within a range of color temperatures.
61. The solid-state lamp of claim 60 , wherein the driver is configured to control the combined light to track a color temperature of an incandescent bulb during dimming.
62. The solid-state lamp of claim 4 , wherein the driver electrically connects the base and the strips.
63. The solid-state lamp of claim 4 , wherein the driver is arranged in the base.
64. The solid-state lamp of claim 4 , wherein the strips are bidirectional light-emitting strips.
65. The solid-state lamp of claim 64 , wherein the strips are arranged to provide 360 degrees of light emission.
66. The solid-state lamp of claim 4 , wherein the base is a first base and the solid-state lamp further comprises a second base arranged opposite the first base, and the first and second base electrically connect the solid-state lamp to the power source.
67. The solid-state lamp of claim 66 , wherein the first end of the strip is arranged at the first base and the second base is arranged at the second end of the strip.
68. The solid-state lamp of claim 4 , wherein each of the connectors is a resilient clip connector.
69. The solid-state lamp of claim 4 , wherein each of the connectors has a first portion and a second portion, the first and second portions being in physical contact with opposite sides of the substrate layer.
70. The solid-state lamp of claim 3 , wherein the substrate layer is a curved flexible substrate layer.
71. The solid-state lamp of claim 3 , wherein the substrate layer extends along a straight line along the axis.
72. The solid-state lamp of claim 3 , wherein the support structure comprises a stiff rod.
73. The solid-state lamp of claim 1 , wherein the strips are electrically connected only at the first end.
74. The solid-state lamp of claim 1 , wherein the substrate layer has a uniform cross section between the first and second ends of the strip.
75. The solid state lamp of claim 1 , wherein the strips are tilted with respect to the axis.
76. The solid state lamp of claim 1 , wherein the strips are tilted with respect to each other.
77. The solid state lamp of claim 1 , wherein the strips are parallel to each other.
78. The solid-state lamp of claim 1 , wherein the strips have an efficacy of at least 78 lm/W at 20 mA drive current and 3.2 V drive voltage.
79. The solid-state lamp of claim 1 , wherein the encapsulant is in physical contact with the bare LED die.
80. The solid-state lamp of claim 79 , wherein the light-diffusing layer is in physical contact with the encapsulant.
81. The solid-state lamp of claim 1 , wherein the light-diffusing layer is distinct from the encapsulant.