Color display devices
View Patent ↗The present invention is directed to color display devices which are capable of displaying multiple color states. The display device comprises a plurality of display cells, wherein each of said display cells is (a) sandwiched between a first layer comprising a common electrode and a second layer comprising a plurality of driving electrodes, wherein at least one of the driving electrodes is a designated electrode, (b) filled with an electrophoretic fluid comprising at least two types of pigment particles dispersed in a solvent or solvent mixture, and (c) capable of displaying at least four color states. The display device may also comprise hiding layers or a brightness enhancement structure on the viewing side.
1. A display device comprising:
(i) a plurality of display cells, wherein each of said display cells
(a) is filled with an electrophoretic fluid comprising at least two different types of pigment particles dispersed in a solvent or solvent mixture, and
(b) is sandwiched between a first layer comprising a common electrode and a second layer comprising at least one designated driving electrode and at least one non-designated driving electrode, wherein the different types of pigment particles are driven to the common electrode, the at least one designated driving electrode or the at least one non-designated electrode, and
(ii) at least one blocking layer for each of said display cells, which at least one blocking layer is positioned corresponding to only the at least one designated driving electrode to allow the pigment particles gathered at the at least one designated driving electrode to be hidden and the pigment particles gathered at the at least one non-designated driving electrode to be visible when the display cell is viewed through the first layer, wherein the at least one block layer and the first layer are on a viewing side and the second layer is on a non-viewing side, and the display cell is operable for displaying at least four color states.
2. The display device of claim 1 , wherein said blocking layer is a black matrix layer.
3. The display device of claim 2 , wherein the width of the black matrix layer is equal to or greater than the width of the designated driving electrode.
4. The display device of claim 1 , wherein said blocking layer is a micro-structure or micro-reflector of a brightness enhancement structure.
5. The display device of claim 4 , wherein the width of the base of the micro-structure or micro-reflector is equal to or greater than the width of the designated driving electrode.
6. The display device of claim 1 , wherein said electrophoretic fluid comprises two types of pigment particles dispersed in a solvent or solvent mixture.
7. The display device of claim 6 , wherein the two types of pigment particles carry opposite charge polarities.
8. The display device of claim 6 , wherein the two types of pigment particles are of different electrophoretic mobilities.
9. The display device of claim 6 , wherein one type of the pigment particles is white and the other type of the pigment particles is red, green or blue.
10. The display device of claim 6 , wherein said solvent or solvent mixture is red, green or blue.
11. The display device of claim 6 , comprising pixels wherein each pixel comprises two sub-pixels.
12. The display device of claim 6 , comprising pixels wherein each pixel comprises three sub-pixels.
13. The display device of claim 6 , comprising pixels wherein each pixel comprises four sub-pixels.
14. The display device of claim 1 , wherein said electrophoretic fluid comprises three types of pigment particles dispersed in a solvent or solvent mixture.
15. The display device of claim 14 , wherein the three types of pigment particles carry different levels of charge polarity.
16. The display device of claim 14 , wherein one type of the pigment particles is white and the other two types of the pigment particles are red and green, red and blue or green and blue.
17. The display device of claim 14 , wherein said solvent or solvent mixture is red, green or blue.
18. The display device of claim 1 , wherein driving electrodes are not aligned with the boundary of the display cell.
19. The display device of claim 1 , wherein the pigment particles are driven to the at least designated driving electrode all at once.
20. The display device of claim 1 , wherein the pigment particles are driven to the designated driving electrode(s) in steps.
21. The display device of claim 1 , wherein said driving electrodes are a grid of at least 2×2.
22. The display device of claim 1 , wherein said display cells are microcups.
23. The display device of claim 1 , wherein said display cells are microcapsules.
24. The display device of claim 1 wherein there is a black background layer above or below the second layer.
25. The display device of claim 1 wherein the second layer is black.