DIRECT-LIT BACKLIGHT HAVING LIGHT SOURCES WITH BIFUNCTIONAL DIVERTERS

• US 20070047219A1
• Filed: 07/20/2006
• Published: 03/01/2007
• Est. Priority Date: 08/27/2005
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Thompson, David, Schardt, Craig, Wheatley, John, Carlson, Torren, Jager, Gregory
• Application Number:
  US11/458,891
• Publication Number:
  US 20070047219A1
• Time in Patent Office: Days
• US Class Current: 362/97.300
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members

Abstract

Direct-lit light backlights and associated methods and components are disclosed. The backlight has an output area such as a front diffuser behind which a plurality of light sources are disposed. A diverter having a first and second reflective surface is disposed between at least two light sources and the front diffuser. The first reflective surface is obliquely disposed to redirect at least some of the light emitted by the light source towards the front diffuser away from the front diffuser. The second reflective surface is obliquely disposed to redirect at least some light propagating laterally relative to the front diffuser towards the front diffuser.

Claims

1. A direct-lit backlight having an output area, comprising:

a first and second light source disposed behind the output area, the first and second light sources being spaced apart from each other and each emitting at least a first light component towards the output area; and

a first diverter disposed between the light sources and the output area and having a first and second reflective surface;

wherein the first reflective surface is obliquely disposed to redirect at least some of the first light component away from the output area, and the second reflective surface is obliquely disposed to redirect at least some of a second light component propagating laterally relative to the output area towards the output area.

2. The backlight of claim 1, wherein the output area is a surface of a diffuser plate.

3. The backlight of claim 1, further comprising a back reflector and reflective side walls, the light sources disposed between the back reflector and the output area.

4. The backlight of claim 1, wherein the first and second light sources are part of a first row of light sources, and the diverter is elongated and oriented to extend parallel to the first row of light sources.

5. The backlight of claim 4, wherein the first light source emits light of a first color and the second light source emits light of a second color different from the first color.

6. The backlight of claim 5, wherein the first row of light sources further includes a third light source that emits light of a third color different from the first and second colors.

7. The backlight of claim 6, wherein the first, second, and third colors are selected from the group of red, green, and blue.

8. The backlight of claim 1, wherein the first and second light sources are LEDs.

9. The backlight of claim 8, wherein the LEDs are packaged to emit at least some light sideways out of the package.

10. The backlight of claim 1, where the first diverter comprises a reflective film, and the first and second reflective surfaces are opposed major surfaces of the reflective film.

11. The backlight of claim 1, wherein the first diverter comprises distinct first and second reflective films, the first reflective film comprising the first reflective surface and the second reflective film comprising the second reflective surface.

12. The backlight of claim 1, wherein the first and second reflective surfaces are flat.

13. The backlight of claim 1, wherein the first and second reflective surfaces reflect light specularly.

14. The backlight of claim 1, wherein the first and second reflective surfaces reflect light diffusely.

15. The backlight of claim 1, wherein the light source has an asymmetric cross-sectional shape.

16. The backlight of claim 1, wherein the first reflective surface is not transmissive.

17. The backlight of claim 1, wherein the first reflective surface is partially transmissive.

18. The backlight of claim 17, wherein the first reflective surface transmits 20% to 80% of normally incident, diffusely incident, or actually incident light.

19. The backlight of claim 1 in combination with a display panel.

20. The combination of claim 19, wherein the display panel comprises a liquid crystal display (LCD).

21. An LCD TV comprising the combination of claim 20.