Solid state lighting apparatus and methods of forming

Patent metadata

Field	Value
Publication number	US-9510413-B2
Application number	US-201213360145-A
Country	US
Kind code	B2
Filing date	Jan 27, 2012
Priority date	Jul 28, 2011
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

A solid state lighting apparatus can include a substrate having first and second opposing surfaces, where at least one of the opposing surfaces is configured to mount devices thereon. A string of chip-on-board light emitting diode (LED) sets, can be on the first surface of the substrate and coupled in series with one another. An ac voltage source input, from outside the solid state lighting apparatus, can be coupled to the first or second surface of the substrate.

First claim

What is claimed is:

1. A solid state lighting apparatus comprising:
a rectifier circuit mounted on a surface of a substrate housed in the solid state lighting apparatus, coupled to an ac voltage source configured to provide a rectified ac voltage to the substrate;
a current source circuit mounted on the surface of the substrate, coupled to the rectifier circuit;
a string of light emitting diode (LED) sets, mounted on the surface of the substrate, coupled in series with one another and to the current source circuit; and
a plurality of current diversion circuits mounted on the surface of the substrate, respective ones of which are coupled to respective nodes of the string and configured to operate responsive to bias state transitions of respective ones of the LED sets.

2. The apparatus of claim 1 , wherein at least the plurality of current diversion circuits comprise discrete electronic component packages mounted on the substrate.

3. The apparatus of claim 1 , wherein the LEDs in the string comprise chip-on-board LEDs mounted on the surface of the substrate.

4. The apparatus of claim 1 , wherein the substrate comprises a flexible circuit substrate, the apparatus further comprising:
a heat sink mounted on an opposing surface of the substrate, thermally coupled to the string of LED sets.

5. The apparatus of claim 1 , wherein the substrate comprises a metal core printed circuit board (MCPCB).

6. The apparatus of claim 5 wherein the MCPCB comprises a metal layer separated from the surface of the substrate by a dielectric layer and configured to conduct heat away from the string of LED sets.

7. The apparatus of claim 5 wherein the MCPCB comprises a dielectric material between first and second metal layers.

8. The apparatus of claim 7 wherein the first metal layer comprises a circuit layer and the second metal layer is configured to conduct heat away from the string of LED sets.

9. The apparatus of claim 1 , further comprising:
a current limiter circuit, on the surface of the substrate, in series with the current source circuit and at least one of the LED sets; and
at least one capacitor, on the surface of the substrate, coupled across the at least one LED set and the current limiter circuit.

10. The apparatus of claim 9 wherein the current limiter circuit is configured to selectively provide current from the current source circuit to the at least one LED set and to the at least one capacitor.

11. The apparatus of claim 9 wherein the rectifier circuit, the current source circuit, the plurality of current diversion circuits, and the current limiter circuit are integrated in an application specific integrated circuit.

12. The apparatus of claim 1 further comprising:
an encapsulant layer, on the surface of the substrate, encapsulating the string of LED sets.

13. The apparatus of claim 12 wherein the encapsulant layer comprises silicone.

14. The apparatus of claim 1 further comprising:
separate encapsulant layers encapsulating LEDs in the string of LED sets, separately.

15. The apparatus of claim 1 wherein the rectifier circuit, the current source circuit, and the plurality of current diversion circuits are included in a single integrated circuit device package.

16. The apparatus of claim 1 , wherein the substrate comprises a silicon substrate, a gallium nitride substrate, a silicon carbide substrate or a graphene substrate.

17. The apparatus of claim 1 further comprising:
an encapsulant barrier, on the substrate, at least partially surrounding LEDs in the sets, configured to reduce a flow of an encapsulant material away from the LEDs during application of the encapsulant material to promote formation of lenses on the string of LED sets.

18. The apparatus of claim 17 wherein a height of the encapsulant barrier above the substrate is less than a height of an upper surface of the LEDs.

19. The apparatus of claim 1 wherein the string of LED sets includes at least three sets coupled in series with one another, each of the three sets including at least two high voltage LEDs coupled in parallel with one another.

20. The apparatus of claim 1 , wherein the ac voltage source comprises at least about 110 volts ac.

21. The apparatus of claim 1 wherein the string of LED sets includes at least three sets coupled in series with one another, each of the three sets including at least two high voltage LEDs coupled in series with one another.

22. The apparatus of claim 1 , wherein the ac voltage source comprises at least about 220 volts ac.

23. The apparatus of claim 1 , wherein at least one set of the string of LED sets comprises at least two high voltage LEDs coupled in parallel or is series with one another and the ac voltage source comprises at least about 110 volts ac or about 220 volts ac.

24. A solid state lighting apparatus comprising:
a substrate having first and second opposing surfaces, at least one of which is configured to mount devices thereon;
a string of chip-on-board light emitting diode (LED) sets, on the first surface of the substrate, coupled in series with one another; and
an ac voltage source input, from outside the solid state lighting apparatus, coupled to the first or second surface of the substrate.

25. The apparatus of claim 24 further comprising:
a rectifier circuit on the first or second surface of the substrate, coupled to the ac voltage source input to provide a rectified ac voltage to the substrate;
a current source circuit on the first or second surface of the substrate, coupled to the rectifier circuit; and
a plurality of current diversion circuits on the first or second surface of the substrate, respective ones of which are coupled to respective nodes of the string and configured to operate responsive to bias state transitions of respective ones of the LED sets.

26. The apparatus of claim 25 , wherein at least the plurality of current diversion circuits comprise discrete electronic component packages mounted on the first surface of the substrate.

27. The apparatus of claim 25 wherein the substrate comprises a flexible circuit substrate, the apparatus further comprising:
a thermally conductive slug in the substrate at a particular position opposite where the string of chip-on-board LED sets are to be mounted thereon.

28. The apparatus of claim 25 , further comprising:
a current limiter circuit, on the first or second surface of the substrate, in series with the current source circuit and at least one of the LED sets; and
at least one capacitor, on the first or second surface of the substrate, coupled across the at least one LED set and the current limiter circuit.

29. The apparatus of claim 24 , wherein the substrate comprises a flexible circuit substrate, the apparatus further comprising:
a heat sink on the second side of the substrate, thermally coupled to the string of chip-on-board LED sets.

30. The apparatus of claim 24 , wherein the substrate comprises a metal core printed circuit board.

31. The apparatus of claim 24 wherein LEDs in the string of chip-on-board LED sets comprise unpackaged light emitting diodes mounted on the substrate.

32. The apparatus of claim 24 wherein the string of chip-on-board LED sets includes at least three sets coupled in series with one another, each of the three sets including at least two ch

Assignees

• Athalye Praneet Jayant
• Ni Liqin
• Van De Ven Antony P
• Underwood Robert D
• Cree Inc

Inventors

• Athalye Praneet Jayant
• Ni Liqin
• Van De Ven Antony P
• Underwood Robert D

Classifications

• H10W90/00

  Package configurations · CPC title

• H05B45/48 Primary

  having LEDs organised in strings and incorporating parallel shunting devices · CPC title

• H10H20/853

  characterised by their shape · CPC title

• H10H20/0362

  of encapsulations · CPC title

• H01L2924/0002

  Electricity · mapped topic