Apparatus and Methods for Backlight Unit with Vertical Interior Reflectors

• US 20080225512A1
• Filed: 03/16/2007
• Published: 09/18/2008
• Est. Priority Date: 03/16/2007
• Status: Active Grant

• Current Assignee: Brightplus Ventures LLC (IPValuation Partners, LLC)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Roberts, John K., You, Chenhua
• Granted Patent: US 8,651,685 B2
• Time in Patent Office: Days
• US Class Current: 362/97
• 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

Provided are solid state backlight devices and methods for forming the same. A solid state backlight unit according to some embodiments of the invention includes a housing having a major surface and multiple LEDs on a first surface of the major surface. The solid state backlight unit also includes a specular reflector proximate to the first surface of the major surface and oriented substantially perpendicular to the first surface of the major surface.

Claims

1. A method of forming a solid state backlight unit for providing light to a display, the method comprising:

mounting a plurality of LEDs to a first surface; and

attaching a first vertical reflector, wherein the first vertical reflector is configured to extend from the first surface, wherein the first vertical reflector is oriented substantially perpendicular to the first surface, and wherein the first vertical reflector is positioned adjacent a first side of the plurality of LEDs.

2. The method of claim 1, further comprising attaching a second vertical reflector, wherein the second vertical reflector is configured to extend from the first surface, wherein the second vertical reflector is oriented substantially perpendicular to the first surface, and wherein the second vertical reflector is positioned adjacent a second side of the plurality of LEDs.

3. The method of claim 1, wherein the attaching a first vertical reflector comprises:

providing a housing first sidewall configured to extend from a first edge of the major surface substantially perpendicularly to the major surface; and

attaching a specularly reflective component to a first sidewall surface, wherein the first sidewall surface has a normal vector that is directed substantially towards the plurality of LEDs.

4. The method of claim 3, wherein the specularly reflective component comprises a metallic tape.

5. The method of claim 3, wherein the specularly reflective component comprises an optical film.

6. The method of claim 1, further comprising engaging the first surface with a diffuse reflector.

7. The method of claim 6, wherein the diffuse reflector comprises a coating on the first surface.

8. A solid state backlight unit configured to backlight a display, comprising:

a plurality of LEDs on a first surface; and

a specular reflector proximate to the first surface and oriented substantially non-parallel to the first surface.

9. The solid state backlight unit of claim 8, further comprising a diffuse reflector on the major surface, the diffuse reflector including a plurality of apertures configured to receive the plurality of LEDs.

10. The solid state backlight unit of claim 8, further comprising:

a first specular reflector having a first reflective surface, wherein the first specular reflector is positioned adjacent a first side of the plurality of LEDs; and

a second specular reflector having a second reflective surface, wherein the second specular reflector is positioned adjacent a second side of the plurality of LEDs.

11. The solid state backlight unit of claim 10, wherein the first reflective surface has a normal vector that intersects with and is perpendicular to the second reflective surface.

12. The solid state backlight unit of claim 8, wherein the housing further comprises a first sidewall and a second sidewall, wherein the first and second sidewalls extend from and are substantially parallel to the first surface, and wherein the first surface and the first and second sidewalls define an optical cavity.

13. The solid state backlight unit of claim 8, wherein the specular reflector comprises aluminum tape.

14. The solid state backlight unit of claim 8, wherein the specular reflector comprises a multilayer optical film.

15. The solid state backlight unit of claim 8, further comprising a means for diffusing light transmitted from an optical cavity that is defined by the first surface, a first sidewall, and a second sidewall.

16. The solid state backlight unit of claim 8, further comprising a diffuser that is positioned substantially parallel to the first surface, wherein the diffuser transmits light from the plurality of LEDs and the specular reflector.

17. A display comprising a solid state backlight unit according to claim 8.

18. A solid state backlight unit, comprising:

at least one emitter configured to radiate light;

a diffuse reflector configured to reflect a first portion of the light radiated from the at least one emitter;

a first vertical reflector configured to reflect a second portion of the light radiated from the at least one emitter;

a second vertical reflector configured to reflect a third portion of the light radiated from the at least one emitter; and

a diffuser configured to partially transmit the light radiated from the at least one emitter, the reflected first portion, the reflected second portion and the reflected third portion.

19. The solid state backlight unit of claim 18, wherein the first and second vertical reflectors are substantially perpendicular to the diffuse reflector and wherein the first vertical reflector is substantially parallel to the second vertical reflector.

20. The solid state backlight unit of claim 18, wherein the first and second vertical reflectors comprise a multilayer optical film.

21. The solid state backlight unit of claim 18, wherein the first and second vertical reflectors comprise a metallic tape.

22. The solid state backlight unit of claim 18, wherein the diffuser is substantially parallel to the diffuse reflector.

23. The solid state backlight unit of claim 18, wherein the first vertical reflector is configured to reflect light to the second vertical reflector and wherein the second vertical reflector is configured to reflect light to the first vertical reflector.