Luminescent sheet covering for LEDs
View Patent ↗A lighting apparatus comprising at least one light emitting diode is disposed on an interconnect board to emit ultraviolet or blue radiation. A polymeric layer including a luminophor is disposed about the lighting apparatus to convert at least a portion of the radiation emitted from the LED into visible light. The polymeric layer is shrinkable to conform to a shape enclosing the light emitting diode.
1. A lighting apparatus, comprising:
at least one light emitting diode which is disposed on an interconnect board to emit ultraviolet or blue radiation, which light emitting diode includes:
a first surface to emit radiation, and
a second surface disposed opposite the first surface; and
a polymeric sheet including a luminophor which is disposed about the lighting apparatus to convert at least a portion of the radiation emitted from the light emitting diode into visible light, the polymeric sheet comprised of polymer molecules that are in a state between stretched and natural.
2. The apparatus of claim 1 , wherein the polymeric sheet further comprises at least a phosphor material.
3. The apparatus of claim 2 , wherein the phosphor is one of:
an inorganic luminescent powder;
an organic luminophor which substantially dissolves in the polymer; and
a nano-particle material.
4. The apparatus of claim 2 , wherein the polymeric sheet further includes:
a polymeric material which is liquefied to one of suspend or dissolve the phosphor material and rolled into a polymeric sheet.
5. The apparatus of claim 4 , wherein a thickness of the polymeric sheet is equal to from about 40 μm to about 400 μm.
6. The apparatus of claim 1 , wherein the polymeric sheet includes at least one of:
polyvinyl chloride,
polyethylene, and
polypropylene.
7. The apparatus of claim 1 , further including:
an enclosure surrounding a radiation generating area of the light apparatus to at least substantially encompass the radiation emitted from the light emitting diode.
8. The apparatus of claim 7 , wherein the polymeric sheet is tightly shrink-wrapped over the light emitting diode first surface to completely cover at least the light emitting diode first surface and portions of the interconnect board adjacent the light emitting diode second surface.
9. The apparatus of claim 8 , wherein the polymeric sheet comprises at least a phosphor which is substantially uniformly distributed over the light emitting diode first surface and portions of the interconnect board adjacent the light emitting diode second surface.
10. The apparatus of claim 7 , including an air gap between the light emitting diode and the radiation converting polymeric sheet.
11. The apparatus of claim 10 , wherein the enclosure has a shape of a hemisphere with the bottom surface of the hemisphere serving to support the light emitting diode and provide a heatsink.
12. The apparatus of claim 1 , wherein the interconnect board is transparent at least in the direction of the light emitting diode second surface, which transparency defines at least one light escaping surface of the interconnect board.
13. The apparatus of claim 12 , wherein the polymeric sheet is shrink-wrapped around the light escaping surface of the board.
14. The apparatus of claim 1 , wherein the interconnect board has a high index of refraction and makes optical contact with the light emitting diode chip and the polymeric layer.
15. The apparatus of claim 1 , further including:
a heatsink disposed on a side of the circuit board opposed to the light emitting diode to dissipate heat generated by the light emitting diode.
16. The apparatus of claim 15 , wherein the heatsink includes a plurality of wings.
17. The apparatus of claim 1 further including an enclosure surrounding a radiation generating area of the apparatus wherein the sheet located next to the enclosure and remotely from the diode.
18. The apparatus of claim 1 wherein the sheet located remotely from the diode, whereby a surface area of the sheet comprises at least 10 times the surface area of the diode and a mount structure of the diode.
19. An illumination device comprising:
a light-transmissive display;
a backlight arranged to illuminate the light-transmissive display, the backlight including:
at least one light emitting diode to emit radiation;
a reflector to reflect the emitted radiation into the light-transmissive display, the reflector including a reflector cavity defining an air gap above the light emitting diode; and
a luminescent shrink-wrap which is disposed to cover the reflector cavity and convert the reflected radiation into visible light, which shrink-wrap includes:
a first surface disposed proximately to the light emitting diode to receive the emitted radiation, and
a second surface disposed distally from the light emitting diode to emit visible light;
wherein the shrink-wrap comprises polymer molecules that are in a state between stretched and natural polymer.
20. The device of claim 19 , wherein the shrink-wrap comprises at least phosphor.
21. The device of claim 20 , wherein the phosphor is one of:
an inorganic luminescent powder;
a rare earth complex;
an organic luminophor; and
a nano-particle material.
22. The device of claim 20 , wherein the shrink-wrap further includes:
a polymeric material which is liquefied to one of suspend or dissolve the phosphor and rolled into a phosphor including polymeric sheet.
23. The device of claim 20 wherein the phosphor uniformly distributed within the shrink-wrap which covers the reflector cavity.
24. The device of claim 19 , wherein the shrink-wrap includes at least one of:
polyvinyl chloride,
polyethylene, and
polypropylene.
25. The device of claim 19 wherein the light emitting diode aligned horizontally below the luminescent shrink-wrap.
26. The device of claim 19 wherein the air gap located adjacent the light emitting diode.
27. The device of claim 19 wherein the shrink-wrap disposed a distance from the diode whereby a surface area of the wrap comprises at least 10 times the surface area of the diode and a mount structure for the diode.