LED backlighting for displays

• US 7,980,743 B2
• Filed: 06/14/2005
• Issued: 07/19/2011
• 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:
  US11/153,724
• Publication Number:
  US 20060279962A1
• Time in Patent Office: 2,226 Days
• Field of Search: 362/560, 362/29, 362/30, 362/33, 362/97, 362/125, 362/227, 362240-242, 362/245, 362/249, 362/294, 362/252, 362/327, 362/355, 362/373, 362/555, 362/600, 362/800, 362/812, 362/97.1, 362/97.2, 362/97.3, 362/2, 362/394, 362/558, 362/559, 362/561, 404/52, 405/41, 405/42, 405/44, 405/64, 405/65, 405/81
• 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. A display system comprising:

a display panel comprising a first major surface and a second major surface; and

a lighting system adapted to provide light proximal to the second major surface of said display panel;

wherein said lighting system comprises;

an illuminating substrate comprising a first major surface facing said display panel and a second major surface opposite the first major surface, said illuminating substrate comprising a substrate core having a first major core surface and a second major core surface opposite said first major core surface, circuit elements disposed on said second major core surface, and a reflective layer covering at least a portion of the first major core surface, and said substrate core, said circuit elements, and said reflective layer together defining an array of mounting holes through said illuminating substrate with the light reflective layer covering at least a portion of the first major surface of said illuminating substrate and said circuit elements comprising at least a portion of said second major surface of said illuminating substrate; and

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

2. The display system recited in claim 1 wherein said light reflective layer comprise at least one member from a group consisting of silver, gold, aluminum, reflective paint, Barium Sulfate, and Titanium Dioxide.

3. The display system recited in claim 1 wherein said light reflective layer comprise diffusion grating.

4. The display system recited in claim 1 further comprising a diffusant layer placed between the display panel and the lighting system, the diffusant layer optically coupled to the illuminating substrate via an optical gel.

5. The lighting system recited in claim 4 wherein said optical gel comprises phosphors.

6. The display system recited in claim 4 wherein said diffusant layer comprises beveled edges.

7. The display system recited in claim 6 wherein said diffusion layer comprises edges beveled at or near critical angle of refraction of the medium.

8. The display system recited in claim 4 wherein said diffusant layer comprises edges having reflective coating.

9. The display system recited in claim 4, wherein the optical gel comprises a material having a refractive index equal to the refractive index of the diffusant layer.

10. The display system recited in claim 4, wherein the diffusant layer comprises a material interspersed with particles of at least one of a refractive material and a reflective material.

11. The display system recited in claim 10, wherein the at least one of a refractive material and a reflective material comprises at least one material selected from a group consisting of barium sulfate, titanium dioxide, silica, and plastic.

12. The display system recited in claim 1 further comprising a heat sink.

13. The display system recited in claim 1 further where each LED module comprising a cluster of LED chips, the LED chips emitting light at different wavelengths or colors.

14. The display system recited in claim 1 wherein each of said LED modules comprises one or more electrically conductive traces and contacts the second major surface of said 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 and at least a portion of each LED module occupies the mounting hole.

15. The display system recited in claim 1 wherein each of said LED modules further comprises a reflector cup defining a cavity with the LED chip of the respective LED module positioned within the cavity.

16. The display system recited in claim 15 wherein each of said reflector cups of said LED modules defines an outer shape that fittingly affixes within said corresponding mounting hole of said array of mounting holes in said illuminating substrate.

17. 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, circuit elements disposed on the second major core surface, and a reflective layer covering at least a portion of the first major core surface, and the substrate core, the circuit elements, and the reflective layer together defining at least one mounting hole through the illuminating substrate with the light reflective layer comprising at least a portion of the first major surface of the illuminating substrate and the circuit elements comprising at least a portion of the second major surface of the illuminating substrate; and

at least one 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.

18. The lighting system recited in claim 17 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.

19. The lighting system recited in claim 17 wherein the light reflective layer comprises diffusion grating.

20. The lighting system recited in claim 17 further comprising a heat sink.

21. The lighting system recited in claim 17 wherein the at least one LED module comprises a cluster of LED chips, the LED chips emitting light at at least two or more different wavelengths or colors.

22. The lighting system recited in claim 17 wherein the at least one mounting hole comprises an array of mounting holes and the at least one LED module comprises an array of LED modules, wherein each of the modules 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 and at least a portion of each of the LED modules occupies a corresponding mounting hole of the array of mounting holes.

23. The lighting system recited in claim 17 wherein the module comprises one or more electrically conductive traces and contacts 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 and at least a portion each LED module occupies the mounting hole.

24. The lighting system recited in claim 17 wherein the at least one mounting hole is defined through the illuminating substrate including the circuit elements for placement therethrough of the at least one LED module.

25. The lighting system recited in claim 17 wherein the LED module further comprises a reflector cup defining a cavity with the LED chip of the LED module positioned within the cavity.

26. The display system recited in claim 25 wherein the reflector cup defines an outer shape that fittingly affixes within the mounting hole in the illuminating substrate.

27. 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;

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

a reflective layer covering at least a portion of the first major core surface with the light reflective layer comprising at least a portion of the first major surface of the illuminating substrate, and the substrate core, the circuit elements, and the reflective layer together defining at least one mounting hole through the illuminating substrate.