Backlight systems containing downconversion film elements

Patent metadata

Field	Value
Publication number	US-10330851-B2
Application number	US-201515505397-A
Country	US
Kind code	B2
Filing date	Aug 19, 2015
Priority date	Aug 21, 2014
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

Methods for improving color uniformity across an LCD backlight unit having a viewable area, a downconversion film element and blue LEDS comprise increasing blue light absorption while reflecting red and green light in at least one edge of the viewable area.

First claim

We claim:

1. An LCD backlight unit comprising:
(a) a downconversion film element;
(b) a light guide adjacent a major surface of the downconversion film;
(c) a support structure adjacent an edge of the downconversion film element and
(d) blue LEDs positioned to introduce light into the light guide;
wherein the support structure comprises a material that absorbs blue light and reflects red and green light on at least its edge adjacent the downconversion film element, wherein the material is selected from the group consisting of yellow plastic, yellow coating, yellow paint, yellow ink, yellow film, yellow tape and multilayer optical film tuned to reflect only red and green light combined with a blue light absorber.

2. The backlight unit of claim 1 wherein the support structure comprises yellow plastic.

3. The backlight unit of claim 1 wherein the material is yellow coating, paint or ink.

4. The backlight unit of claim 1 wherein the material is a yellow film or tape.

5. The backlight unit of claim 1 wherein the material is a multilayer optical film tuned to reflect only red and green light combined with a blue light absorber.

6. The backlight unit of claim 1 wherein the downconversion film element is a quantum dot film.

7. The backlight unit of claim 1 wherein the backlight unit is edge-lit.

8. A method of improving color uniformity across an LCD backlight unit having a viewable area comprising:
providing an LCD backlight unit comprising a downconversion film element, a light guide adjacent a major surface of the downconversion film and blue LEDs positioned to introduce light into the light guide, and
increasing blue light absorption while reflecting red and green light in at least one edge of the viewable area.

9. The method of claim 8 wherein the LCD backlight unit further comprises a support structure adjacent an edge of the downconversion film element and increasing blue light absorption while reflecting red and green light in at least one edge of the viewable area comprises applying a material that absorbs blue light and reflects red and green light to an edge of the support structure adjacent the downconversion film element.

10. The method of claim 8 wherein increasing blue light absorption while reflecting red and green light in at least one edge of the viewable area comprises applying a material that absorbs blue light and reflects red and green light to at least one edge of the light guide.

11. The method of claim 8 wherein the LCD backlight unit further comprises a light redirecting film and increasing blue light absorption while reflecting red and green light in at least one edge of the viewable area comprises applying a material that absorbs blue light and reflects red and green light overlapping the edge of the light redirecting film or the edge of the downconversion film element.

12. The method of claim 9 wherein the material is yellow coating, paint or ink.

13. The method of claim 10 wherein the material is yellow coating, paint or ink.

14. The method of claim 11 wherein the material is yellow coating, paint or ink.

15. The method of claim 9 wherein the material is yellow film or tape.

16. The method of claim 10 wherein the material is yellow film or tape.

17. The method of claim 11 wherein the material is yellow film or tape.

18. The method of claim 9 wherein the material is a multilayer optical film tuned to reflect only red and green light combined with a blue light absorber.

19. The method of claim 10 wherein the material is a multilayer optical film tuned to reflect only red and green light combined with a blue light absorber.

20. The method of claim 11 wherein the material is a multilayer optical film tuned to reflect only red and green light combined with a blue light absorber.

21. The method of claim 8 wherein the downconversion film element is a quantum dot film.

Assignees

• 3M Innovative Properties Co

Inventors

• Tibbits Joshua D
• Yang Yu
• Su Jiangang
• Zhao Feng
• Yang Wenlong
• Fan Shu-Ching

Classifications

• G02B6/0055

  Reflecting element, sheet or layer · CPC title

• G02F1/133609 Primary

  including means for improving the color mixing, e.g. white · CPC title

• G02B6/005 Primary

  provided by one optical element, or plurality thereof, placed on the light output side of the light guide · CPC title

• G02B6/0088

  of the light guide or other optical sheets in the package · CPC title

• G02F2001/133614

  Physics · mapped topic