Thin backlight with reduced bezel width

Patent metadata

Field	Value
Publication number	US-9772439-B2
Application number	US-201615016963-A
Country	US
Kind code	B2
Filing date	Feb 5, 2016
Priority date	Feb 5, 2016
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A backlight includes a first lightguide having a first portion and a second portion, wherein the second portion is dimensioned smaller that the first portion so as to form a rim along at least a part of the first light guide. At least one light source is positioned under the rim and separated from the first lightguide by a space, where a majority of the light emitted by the at least one light source being along a first axis of the at least one light source. The at least one light source is arranged to position the at least one axis at an angle away from a center of the lightguide in a plane parallel to the rim.

First claim

What is claimed is:

1. A backlight, comprising:
a first lightguide having a first portion and a second portion, wherein the second portion is dimensioned smaller that the first portion so as to form a rim along at least a part of the first light guide; and
at least one light source positioned under the rim and separated from the first lightguide by a space, a majority of the light emitted by the at least one light source being along a first axis of the at least one light source,
wherein the at least one light source is arranged to position the at least one axis at an angle away from a center of the lightguide in a plane parallel to the rim.

2. The backlight according to claim 1 , wherein the first portion and the second portion are formed as a first cylinder and a second cylinder concentric with the first cylinder, and a diameter of the first cylinder is greater than a diameter of the second cylinder.

3. The backlight according to claim 1 , wherein the space comprises air.

4. The backlight according to claim 1 , wherein the inner surface comprises extraction features configured to out-couple light from the second lightguide to the first in-coupling surface of the first lightguide.

5. The backlight according to claim 1 , wherein the second lightguide comprises at least one cutaway section forming a second in-coupling surface for receiving light from the at least one light source, and the at least one light source is arranged within the cutaway section.

6. The backlight according to claim 1 , wherein the first axis of the at least one light source is arranged at an angle relative to a radial center of the second lightguide.

7. The backlight according to claim 1 , further comprising:
a first reflector; and
a second reflector, wherein the light emitting device is arranged between the first reflector and the second reflector, and the first reflector is arranged between the rim and the at least one light source.

8. The backlight according to claim 1 , wherein the at least one light source comprises a plurality of light sources.

9. The backlight according to claim 8 , wherein each light source of the plurality of light sources is arranged on a side of the first lightguide opposite another light source of the plurality of light sources.

10. The backlight according to claim 1 , wherein a part of the first portion of the first lightguide does not include the rim.

11. The backlight according to claim 1 , wherein the first lightguide comprises one of a circular form factor or a rectangular form factor.

12. The backlight according to claim 1 , wherein the first lightguide comprises a rectangular form factor having four sides, and the rim comprises a first rim portion arranged on one of the four sides.

13. The backlight according to claim 12 , wherein the rim further comprises a second rim portion, the second rim portion arranged on a side of the four sides opposite the first rim portion.

14. The backlight according to claim 1 , wherein the second lightguide comprises a serrated surface.

15. The backlight according to claim 14 , wherein the serrated surface comprises a first surface and a second surface, the first and second surface sloping in opposite directions.

16. The backlight according to claim 15 , wherein the first axis is arranged perpendicular to one of the first surface or the second surface.

17. The backlight according to claim 1 , wherein a side of the first lightguide opposing the first light source has either another LED array or a reflecting structure.

18. A backlight system, comprising a plurality of backlights according to claim 1 arranged in a tessellating configuration, wherein the plurality of backlights are independently controllable to enable selective dimming of the backlight system.

Assignees

• Sharp Kk

Inventors

• Montgomery David James

Classifications

• G02B6/008

  of the partially overlapping type · CPC title

• G02B6/0021

  for housing at least a part of the light source, e.g. by forming holes or recesses · CPC title

• G02B6/0023

  provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source · CPC title

• G02B6/0055

  Reflecting element, sheet or layer · CPC title

• G02B6/0013

  Means for improving the coupling-in of light from the light source into the light guide (coupling light into light guides in general G02B6/42) · CPC title