LED backlighting for displays

• US 8,308,331 B2
• Filed: 07/01/2011
• Issued: 11/13/2012
• Est. Priority Date: 06/14/2005
• Status: Active Grant

• Current Assignee: Brightplus Ventures LLC (IPValuation Partners, LLC)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Loh, Ban P.
• Primary Examiner(s): Sawhney, Hargobind S
• Application Number:
  US13/175,600
• Publication Number:
  US 20110261554A1
• Time in Patent Office: 501 Days
• Field of Search: 362/29, 362/30, 362/33, 362/97.1, 362/97.2, 362/97.3, 362/125, 362/227, 362/240, 362/241, 362/242, 362/245, 362/249.02, 362/373, 362/394, 362/555, 362/558, 362/559, 362/560, 362/561, 362/800, 362/812, 404/52, 405/41, 405/42, 405/44, 405/64, 405/65, 405/81, 359/613, 359/819, 257 98-100, 257/774
• US Class Current: 362/561
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133628 with cooling means
• CPC Class Codes: H01L 2224/48091 Arched
• 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

Abstract

A display system including a display panel having a first major surface and a second major surface and a lighting system adapted to provide uniform luminance proximal to the display panel is disclosed. The lighting system includes an illuminating substrate having a first major surface with reflective coating and a second major surface. The illuminating substrate defines an array of mounting holes, each hole occupied by an LED module. An array of light emitting diode (LED) modules are affixed to the illuminating substrate, each module including at least one light emitting diode adapted to emit light. The lighting system can also include a diffusant layer which can be optically coupled to the illuminating substrate by soft optical gel and is placed close to or made to contact the display panel. The optical gel may contain phosphors or other optical substance for added optical performance to the lighting system. The diffusant layer has beveled edges at critical angle of refraction or coated with reflective material to minimize light loss at its edges. Each of the LED modules includes at least one LED chip, conductive traces connected to the LED chip and a heat sink.

Claims

1. An illuminating substrate comprising:

a first major surface;

a second major surface opposite the first major surface;

a substrate core having a first major core surface and a second major core surface opposite the first major core surface, the first major core surface being on a same side of the substrate core as the first major surface of the illuminating substrate and the second major core surface being on a same side of the substrate core as the second major surface of the illuminating substrate; and

circuit elements disposed on the second major core surface, the circuit elements comprising at least a portion of the second major surface of the illuminating substrate; and

the substrate core and the circuit elements together defining at least one mounting hole through the illuminating substrate.

2. The illuminating substrate of claim 1 further comprising a light reflective layer covering at least a portion of the first major core surface of the substrate core.

3. The illuminating substrate of claim 2 wherein the light reflective layer comprises at least one member from a group consisting of silver, gold, aluminum, reflective paint, barium sulfate, and titanium dioxide.

4. The illuminating substrate of claim 2 wherein the light reflective layer comprise diffusion grating.

5. The illuminating substrate of claim 2 wherein the reflective layer comprises at least a portion of the first major surface of the illuminating substrate.

6. The illuminating substrate of claim 1 wherein the at least one mounting hole comprises an array of mounting holes.

7. The illuminating substrate of claim 6 further comprising an array of light emitting diode (LED) modules, each module comprising an LED chip, wherein each of the modules is substantially adjacent to the second major surface and forms an electrical connection with the circuit elements of the second major surface and at least a portion of each of the LED modules occupying a corresponding mounting hole of the array of mounting holes.

8. The illuminating substrate of claim 7 wherein each of the LED modules further comprises a reflector cup defining a cavity with the LED chip of the respective LED module positioned within the cavity.

9. The illuminating substrate of claim 8 wherein each of the reflector cups defines an outer shape that fittingly affixes within the corresponding mounting hole in the illuminating substrate.

10. The illuminating substrate of claim 7 wherein the LED module comprises at least one LED chip and conductive traces connected to the LED chip.

11. The illuminating substrate of claim 10 wherein the circuit elements are adapted to connect to the conductive traces of the LED module.

12. The illuminating substrate of claim 7 wherein each LED module comprises a cluster of LED chips, the LED chips emitting light at different wavelengths or colors.

13. The illuminating substrate of claim 1 further comprising a diffusant layer disposed over at least a portion of the first surface, the diffusant layer optically coupled to the first surface via an optical gel.

14. The illuminating substrate of claim 13 wherein the optical gel comprises phosphors.

15. The illuminating substrate of claim 13 wherein the diffusant layer comprises edges having a reflective coating.

16. The illuminating substrate of claim 13, wherein the optical gel comprises a material having a refractive index equal to the refractive index of the diffusant layer.

17. The illuminating substrate of claim 1 wherein the circuit elements comprise conductive traces.

18. The illuminating substrate of claim 1 wherein the first major core surface of the substrate core is adjacent at least a portion of the first major surface of the illuminating substrate.

19. A lighting system comprising:

an illuminating substrate comprising a first major surface and a second major surface opposite the first major surface, the illuminating substrate comprising;

a substrate core having a first major core surface and a second major core surface opposite the first major core surface, the first major core surface being on a same side of the substrate core as the first major surface of the illuminating substrate and the second major core surface being on a same side of the substrate core as the second major surface of the illuminating substrate;

circuit elements disposed on the second major core surface, the circuit elements comprising at least a portion of the second major surface of the illuminating substrate; and

the substrate core and the circuit elements together defining a mounting hole through the illuminating substrate; and

a light emitting diode (LED) module, the module comprising an LED chip, wherein the module is substantially adjacent to the second major surface of the illuminating substrate and forms an electrical connection with the circuit elements of the second major surface of the illuminating substrate and at least a portion of the LED module occupies the mounting hole.

20. The lighting system of claim 19 further comprising a light reflective layer covering at least a portion of the first major core surface of the substrate core.

21. The lighting system of claim 20 wherein the light reflective layer comprises at least one member from a group consisting of silver, gold, aluminum, reflective paint, barium sulfate, and titanium dioxide.

22. The lighting system of claim 20 wherein the light reflective layer comprises diffusion grating.

23. The lighting system of claim 20 wherein the reflective layer comprises at least a portion of the first major surface of the illuminating substrate.

24. The lighting system of claim 19 further comprising a heat sink.

25. The lighting system of claim 19 wherein the LED module comprises a cluster of LED chips, the LED chips emitting light at two or more different wavelengths or colors.

26. The lighting system of claim 19 wherein the LED module comprises one or more electrically conductive traces and is substantially adjacent to the second major surface of the illuminating substrate such that the one or more electrically conductive traces electrically connect with the circuit elements of the second major surface of the illuminating substrate.

27. The lighting system of claim 19 wherein the LED module further comprises a reflector cup defining a cavity with the LED chip of the LED module positioned within the cavity.

28. The lighting system of claim 27 wherein the reflector cup of the LED module defines an outer shape that fittingly affixes within the corresponding mounting hole in the illuminating substrate.

29. The lighting system of claim 19 wherein the first major core surface of the substrate core is adjacent at least a portion of the first major surface of the illuminating substrate.