Liquid crystal display having a field emission backlight

• US 8,259,258 B2
• Filed: 10/04/2006
• Issued: 09/04/2012
• Est. Priority Date: 06/28/2006
• Status: Active Grant

• Current Assignee: InterDigital Madison Patent Holdings (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Gorog, Istvan, Ritt, Peter Michael
• Primary Examiner(s): Peace, Rhonda
• Application Number:
  US12/308,906
• Publication Number:
  US 20090185110A1
• Time in Patent Office: 2,162 Days
• Field of Search: 349/70, 349/71
• US Class Current: 349/71
• CPC Class Codes: G02F 1/133602 Direct backlight
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/133625 Electron stream lamps
• CPC Class Codes: H01J 63/04 Vessels provided with luminescent coatings; Selection of materials for the coatings
• CPC Class Codes: H01L 21/4814 Conductive parts

Abstract

An LCD display has a programmable backlight device that produces multiple different color fields from multiple different phosphor elements. The backlight device can be a low resolution FED device. The phosphor is applied by an electrophotographic screening process or direct electrostatic screening process. The FED device can further incorporate a wide gamut phosphor.

Claims

1. A liquid crystal display comprising:

a liquid crystal front end component having a plurality of liquid crystal pixels, the liquid crystal pixels being aligned in repeat columns, the repeat columns having a pitch, the repeat columns extending in a first direction; and

,

a field emission backlight component having a plurality of individual elements of phosphor, the individual elements of phosphor being aligned in columns, the columns of the individual elements of phosphor extending in the first direction;

wherein the adjacent columns of the plurality of individual elements of phosphor have center-to-center spacings that are larger than the pitch of the repeat columns of the liquid crystal pixels.

2. The liquid crystal display of claim 1, wherein the columns of the individual elements of phosphor are grouped into repeat units and different columns in the repeat units differ in color.

3. The liquid crystal display of claim 2, wherein the individual elements of the field emission backlight component are programmable and synchronized such that selected groups of the individual elements will activate in conjunction with activation of associated liquid crystal cells of the liquid crystal component.

4. The liquid crystal display of claim 2, wherein at least some of the individual elements comprise a water incompatible phosphor.

5. The liquid crystal display of claim 4, wherein one phosphor of the plurality of individual elements is strontium thiogallate:

europium.

6. The liquid crystal display of claim 2, wherein the field emission backlight component has 10 or more of the repeat units.

7. The liquid crystal display of claim 6, wherein the individual elements of the field emission backlight component are programmable and synchronized such that selected groups of the individual elements will activate in conjunction with activation of associated liquid crystal cells of the liquid crystal component.

8. The liquid crystal display of claim 6, wherein the field emission backlight component operates at 10-20 kV.

9. The liquid crystal display of claim 1, wherein at least some of the individual elements comprise a water incompatible phosphor.

10. The liquid crystal display of claim 9, wherein one phosphor of the plurality of individual elements is strontium thiogallate:

europium.

11. The liquid crystal display of claim 1, wherein the individual elements of the field emission backlight component are programmable and synchronized such that selected groups of the individual elements will activate in conjunction with activation of associated liquid crystal cells of the liquid crystal component.

12. The liquid crystal display of claim 1, wherein a ratio of the number of columns of the individual elements of phosphor to the number of repeat columns of liquid crystal pixels is in the range of 1:

3-1000.

13. The liquid crystal display of claim 12, wherein the individual elements of the field emission backlight component are programmable and synchronized such that selected groups of the individual elements will activate in conjunction with activation of associated liquid crystal cells of the liquid crystal component.

14. The liquid crystal display of claim 13, wherein an anode plate and a cathode plate of the field emission backlight component have a spacing of 1-5 mm.

15. The liquid crystal display of claim 12, wherein the field emission backlight component operates at 10-20 kV.

16. The liquid crystal display of claim 1, wherein a ratio of the number of columns of the individual elements of phosphor to the number of repeat columns of liquid crystal pixels is in the range of 1:

100-1000.

17. The liquid crystal display of claim 16, wherein the individual elements of the field emission backlight component are programmable and synchronized such that selected groups of the individual elements will activate in conjunction with activation of associated liquid crystal cells of the liquid crystal component.

18. The liquid crystal display of claim 17, wherein an anode plate and a cathode plate of the field emission backlight component have a spacing of 1-5 mm.

19. The liquid crystal display of claim 1, wherein the field emission backlight component has a cathode comprising carbon nanotubes for emitting electrons which are to strike the phosphor of the plurality of individual elements.

20. The liquid crystal display of claim 1, wherein the columns of the individual elements of phosphor are grouped into repeat units and different columns in the repeat units differ in color.

21. The liquid crystal display of claim 20, wherein the individual elements of the field emission backlight component are programmable and synchronized such that selected groups of the individual elements will activate in conjunction with activation of associated liquid crystal cells of the liquid crystal component.

22. The liquid crystal display of claim 21, wherein at least some of the individual elements comprise a water incompatible phosphor.

23. The liquid crystal display of claim 22, wherein one phosphor of the plurality of individual elements is strontium thiogallate:

europium.

24. The liquid crystal display of claim 23, wherein the field emission backlight component operates at 10-20 kV.