LED BACKLIGHT

• US 20080074901A1
• Filed: 09/21/2006
• Published: 03/27/2008
• Est. Priority Date: 09/21/2006
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Meis, Michael A., Aeling, Ellen O., David, John R.
• Granted Patent: US 7,481,563 B2
• Time in Patent Office: Days
• US Class Current: 362/612
• CPC Class Codes: F21S 8/00 Lighting devices intended for fixed installation F21S9/00, F21S10/00 take precedence; using a string or strip of light sources F21S4/00
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity

Abstract

An LED backlight assembly is disclosed. The assembly includes a housing having a plurality of internal surfaces. At least one of the internal surfaces is a light emission surface and an opposing surface is a reflective surface. An optical film is disposed between the light emission surface and the reflective surface. The optical film includes at least one of a diffusing film, a reflective polarizing film, a multilayer optical film, and a structured surface film. An array of LEDs in electrical communication is disposed on the optical film. At least one LED of the array of LEDs has an illumination field that is directed toward the reflective surface.

Claims

1. An LED backlight assembly comprising:

a housing having a plurality of internal surfaces, at least one of the internal surfaces is a light emission surface and an opposing surface is a reflective surface;

an optical film disposed between the light emission surface and the reflective surface, the optical film comprising at least one of a diffusing film, a reflective polarizing film, a multilayer optical film, and a structured surface film; and

an array of LEDs in electrical communication disposed on the optical film, wherein at least one LED of the array of LEDs has an illumination field that is directed toward the reflective surface.

2. The assembly of claim 1, wherein the reflective surface comprises a diffusely reflective surface.

3. The assembly of claim 1, wherein the LEDs of the array of LEDs are in electrical connection with conductors, and the conductors are disposed on the optical film.

4. The assembly of claim 1, wherein the optical film is a multilayer optical film comprising a brightness enhancing film.

5. The assembly of claim 1, wherein the optical film is a reflective polarizing film.

6. The assembly of claim 1, wherein the optical film is a multilayer optical film comprising a mirror film.

7. The assembly of claim 6, wherein the mirror film comprises regions on the film that have a higher degree of light transmission than other regions of the film.

8. The assembly of claim 1, wherein the optical film is a structured surface film.

9. The assembly of claim 8, wherein the structured surfaced film comprises an embossed film.

10. The assembly of claim 1, wherein the optical film is a diffusing film.

11. The assembly of claim 1, wherein the light emission surface is a diffusely transmissive surface.

12. The assembly of claim 1, wherein the optical film is corrugated and portions of the corrugated optical film contact the reflective surface.

13. The assembly of claim 1, wherein the optical film is a reflective polarizing film.

14. A method of making a backlight assembly comprising:

providing a housing having a plurality of internal surfaces, at least one of the internal surfaces is a light emission surface and an opposing surface is a reflective surface;

disposing an array of LEDs and conductors on an optical film, the optical film comprising at least one of a diffusing film, a reflective polarizing film, a multilayer optical film, and a structured surface film; and

placing the optical film between the light emission surface and the reflective surface such that at least one LED of the array of LEDs has an illumination field directed toward the reflective surface.

15. The method of claim 14, wherein the disposing step comprises disposing the array of LEDs and conductors on the optical film, wherein the LEDs of the array of LEDs are in electrical connection with conductors.

16. The method of claim 14, further comprising thermoforming the optical film to form a non-planar thermoformed optical film.

17. The method of claim 14, further comprising thermoforming the optical film to form a corrugated thermoformed optical film.

18. The method of claim 14, further comprising thermoforming the optical film to form a non-planar thermoformed optical film and the placing step comprises placing the optical film between the light emission surface and the reflective surface such that portions of the non-planar thermoformed optical film are disposed on the reflective surface.

19. The method of claim 14, wherein the reflective surface comprises a diffusely reflective surface.

20. An LED backlight assembly comprising:

a housing having a plurality of internal surfaces, at least one of the internal surfaces is a light emission surface and an opposing surface is a reflective surface;

an optical film disposed between the light emission surface and the reflective surface, the optical film comprising at least one of a diffusing film, a reflective polarizing film, a multilayer optical film, and a structured surface film, wherein the optical film is non-planar and portions of the optical film are disposed on the reflective surface; and

an array of LEDs in electrical communication disposed on the optical film, wherein at least one LED of the array of LEDs has an illumination field that is directed toward the reflective surface.

21. An LED array according to claim 20, wherein the LEDs of the array of LEDs are in electrical connection with conductors, and the conductors are disposed on the optical film.

22. The assembly of claims 20, wherein the reflective surface comprises a diffusely reflective surface.