ELECTROPHORETIC DISPLAY WITH ENHANCED CONTRAST

• US 20110261433A1
• Filed: 04/21/2011
• Published: 10/27/2011
• Est. Priority Date: 04/22/2010
• Status: Active Grant

• Current Assignee: E Ink California, LLC (E Ink Corporation)
• Original Assignee: E Ink California, LLC (E Ink Corporation)
• Inventors: Sprague, Robert A., Lin, Craig
• Granted Patent: US 9,140,952 B2
• Time in Patent Office: Days
• US Class Current: 359/296
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1681 having two or more microcells partitioned by walls, e.g. of microcup type

Abstract

The present invention is directed to an electrophoretic display with enhanced contrast. The invention is directed to an electrophoretic display comprising: a first layer comprising a common electrode, a second layer comprising at least one collecting pixel electrode, a plurality of display cells which are sandwiched between the first layer and the second layer and are filled with an electrophoretic fluid comprising charged pigment particles dispersed in a solvent or solvent mixture; and a background layer. More specifically, the invention provides an electrophoretic display having the dark color state darker while maintaining the same intensity of the lighter color state.

Claims

1. An electrophoretic display comprising:

(a) a first layer comprising a common electrode;

(b) a second layer comprising at least one collecting pixel electrode;

(c) a plurality of display cells which are sandwiched between the first layer and the second layer and are filled with an electrophoretic fluid comprising charged pigment particles dispersed in a solvent or solvent mixture; and

(d) a background layer which has the same color as the solvent or solvent mixture.

2. The display of claim 1, wherein the second layer has one collecting pixel electrode.

3. The display of claim 1, wherein the second layer has more than one collecting pixel electrode and they are electrically connected.

4. The display of claim 1, wherein the percentage of the total collecting pixel electrode area in the area of the second layer is less than about 95%.

5. The display of claim 1, wherein the percentage of the total collecting pixel electrode area in the area of the second layer is less than about 75%.

6. The display of claim 1, wherein the percentage of the total collecting pixel electrode area in the area of the second layer is less than about 50%.

7. The display of claim 1, wherein the percentage of the total collecting pixel electrode area in the area of the second layer is less than about 30%.

8. The display of claim 1, wherein the charged pigment particles are white.

9. The display of claim 8, wherein both the solvent or solvent mixture and the background layer are black.

10. The display of claim 8, wherein both the solvent or solvent mixture and the background layer are red, green, or blue.

11. The display of claim 1, wherein the color of the background layer is more intense than the color of the solvent or solvent mixture.

12. The display of claim 1, wherein the second layer further comprising at least one non-collecting pixel electrode which is not electrically connected to any of the collecting pixel electrodes.

13. An electrophoretic display comprising:

(a) a first layer comprising a common electrode;

(b) a second layer comprising at least one collecting pixel electrode;

(c) a plurality of display cells which are sandwiched between the first layer and the second layer and are filled with an electrophoretic fluid comprising two types of charged pigment particles of two contrasting colors and oppositely charged, dispersed in a solvent or solvent mixture; and

(d) a background layer which has the same color as the darker color of the two contrasting colors.

14. The display of claim 13, wherein the second layer has one collecting pixel electrode.

15. The display of claim 13, wherein the second layer has more than one collecting pixel electrode and they are electrically connected.

16. The display of claim 13, wherein the percentage of the total pixel electrode area in the area of the second layer is less than about 95%.

17. The display of claim 13, wherein the percentage of the total pixel electrode area in the area of the second layer is less than about 75%.

18. The display of claim 13, wherein the percentage of the total pixel electrode area in the area of the second layer is less than about 50%.

19. The display of claim 13, wherein the percentage of the total pixel electrode area in the area of the second layer is less than about 30%.

20. The display of claim 13, wherein the two types of charged pigment particles are white and black dispersed in a clear and colorless solvent or solvent mixture.

21. The display of claim 13, wherein the color of the background layer is more intense than the darker color of the two contrasting colors.

22. The display of claim 13, wherein the second layer further comprising at least one non-collecting pixel electrode which is not electrically connected to any of the collecting pixel electrodes.