Flat panel liquid crystal display

• US 6,439,731 B1
• Filed: 08/27/1999
• Issued: 08/27/2002
• Est. Priority Date: 04/05/1999
• Status: Expired due to Term

• Current Assignee: Alliedsignal Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Wolfe, Steve, Hoffman, Scott, Johnson, Rick, Barakchi, Saied, Deutch, Keith, Henke, Darrell
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Sawhney, Hargobind S.
• Application Number:
  US09/384,137
• Time in Patent Office: 1,096 Days
• Field of Search: 362/230, 362/231, 362/246, 362/355, 362/800, 362/29, 362/812, 362/561, 349/61, 349/64, 349/62, 257/79, 257/80, 257/81, 257/84, 257/88, 257/89, 257/98, 359/247
• US Class Current: 362/29
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133628 with cooling means
• CPC Class Codes: Y10S 362/80 Light emitting diode
• CPC Class Codes: Y10S 362/812 Signs

Abstract

A device and method for backlighting a liquid crystal display device using an array of light emitting diodes mounted in a cavity behind the liquid crystal display.

Claims

1. A backlighted low-profile liquid crystal display device, comprising:

an optical chamber having first and second opposing spaced apart faces;

a liquid crystal display mounted on one of said first and second faces of said optical chamber;

a printed circuit board having first and second essentially parallel surfaces, one of said first and second surfaces mounted to another of said first and second faces of said optical chamber;

a plurality of light emitting diodes arranged in a two-dimensional array across essentially the entirety of said one of said first and second surfaces of said printed circuit board mounted to said optical chamber for essentially direct backlighting of said liquid crystal display;

a brightness adjusting circuit disposed on said printed circuit board surface opposite said light emitting diodes;

a heat sink disposed adjacent to said printed circuit board surface opposite said light emitting diodes;

wherein said brightness adjusting circuit is further disposed in a nested arrangement between said printed circuit board surface opposite said light emitting diodes and said heat sink.

2. The backlighted liquid crystal display device recited in claim 1, wherein said light emitting diodes radiate white light.

3. The backlighted liquid crystal display device recited in claim 2, wherein said light emitting diodes are arranged in combinations of light emitting diodes radiating in different ones of the three primary color bands, whereby said light emitting diodes generate white light.

4. The backlighted liquid crystal display device recited in claim 2, wherein each of said light emitting diodes radiates white colored light.

5. The backlighted liquid crystal display device recited in claim 2, further comprising an optical diffusion panel adjacent said light emitting diodes opposite said printed circuit board.

6. The backlighted liquid crystal display device recited in claim 2, wherein said one of said first and second surfaces of said printed circuit board having said plurality of light emitting diodes arranged thereon further includes a light-reflective finish formed thereon.

7. The backlighted liquid crystal display device recited in claim 2, wherein internal surfaces of said optical chamber are formed with a light-reflective finish.

8. A white backlighted low-profile liquid crystal display device, comprising:

an optical chamber having two opposing spaced apart mounting surfaces;

a conventional liquid crystal display mounted to one of said mounting surfaces of said optical chamber; and

a layered illumination assembly mounted to a different one of said mounting surfaces of said optical chamber in an essentially direct backlighting relationship with said liquid crystal display, said layered illumination assembly including;

a) a printed circuit board,

b) a two-dimensional arrangement of light emitting diodes covering essentially one entire surface of said printed circuit board, said light emitting diodes radiating white colored light,

c) a brightness adjusting circuit disposed on a printed circuit board surface opposite said light emitting diodes;

d) a heat sink disposed adjacent to said printed circuit board surface opposite said light emitting diodes;

wherein said brightness adjusting circuit is further disposed in a nested arrangement between said printed circuit board surface opposite said light emitting diodes and said heat sink.

9. The white backlighted liquid crystal display device recited in claim 8, wherein said layered illumination assembly further comprises an optical diffusion panel adjacent said light emitting diodes opposite said printed circuit board.

10. The while backlighted liquid crystal display device recited in claim 8, wherein said light emitting diodes further comprise a mixture of light emitting diodes radiating in different ones of red, green and blue light bands, whereby said mixture of light emitting diodes generates white light.

11. The white backlighted liquid crystal display device recited in claim 8, wherein each of said light emitting diodes radiates in the white light band.

12. In a low-profile liquid crystal display device, a layered illumination assembly in an essentially direct backlight relationship with a liquid crystal display panel, the layered illumination assembly, comprising:

a printed circuit board;

a two-dimensional arrangement of light emitting diodes mounted on one surface of said printed circuit board and essentially filling the entirety of said one surface, said light emitting diodes radiating white colored light essentially directly upon the liquid crystal display device;

a brightness adjusting circuit disposed on a printed circuit board surface opposite said light emitting diodes;

a heat sink disposed adjacent to said printed circuit board surface opposite said arrangement of light emitting diodes;

wherein said brightness adjusting circuit is further disposed in a nested arrangement between said printed circuit board surface opposite said light emitting diodes and said heat sink.

13. The layered illumination assembly recited in claim 12, further comprising an optical diffusion panel adjacent said light emitting diodes opposite said printed circuit board.

14. The layered illumination assembly recited in claim 13, wherein said light emitting diodes further comprise a mixture of light emitting diodes radiating light in different ones of the three primary color bands, whereby white colored light is generated.

15. The layered illumination assembly recited in claim 13, wherein said light emitting diodes further comprise a plurality of light emitting diodes each radiating white colored light.

16. A method of backlighting a low-profile liquid crystal display panel with white light using light emitting diodes, the method comprising:

mounting a liquid crystal display panel on a first surface of an optical chamber;

mounting a plurality of light emitting diodes in a two-dimensional array essentially covering the surface of a printed circuit board, said light emitting diodes generating an essentially white colored light;

mounting said printed circuit board on a second surface of said optical chamber in an essentially direct backlighting relationship to and spaced away from said liquid crystal display panel;

mounting a heat dissipating device in layered relationship with said printed circuit board on a side of said printed circuit board opposite to said light emitting diodes;

mounting a brightness adjusting circuit on said printed circuit board side opposite said light emitting diodes and further disposed in a nested arrangement between said printed circuit board surface opposite said light emitting diodes and said heat sink; and

backlighting said liquid crystal display panel with essentially uniform illumination.

17. The method recited in claim 16, further comprising mounting an optical diffusing device in layered relationship with said printed circuit board and said heat dissipating device on a side of said printed circuit board opposite said light emitting diodes.

18. The method recited in claim 17, wherein said plurality of light emitting diodes is a mixture of light emitting diodes radiating in different ones of red, blue and green light bands.

19. The method recited in claim 17, wherein said plurality of light emitting diodes each radiate light in a white colored light band.