Color electrophoretic display

• US 9,013,783 B2
• Filed: 06/19/2014
• Issued: 04/21/2015
• Est. Priority Date: 06/02/2011
• Status: Active Grant

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: E Ink California, LLC (E Ink Holdings Incorporated)
• Inventors: Sprague, Robert A.
• Primary Examiner(s): CHOI, WILLIAM C
• Application Number:
  US14/309,727
• Publication Number:
  US 20140340737A1
• Time in Patent Office: 306 Days
• Field of Search: 359/296, 345/107, 430/32, 204/600
• US Class Current: 359/296
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 2001/1678 characterised by the composition or particle type
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

The present invention is directed to a color display device wherein each of the display cells is filled with an electrophoretic fluid comprising two types of charged pigment particles dispersed in a colored medium. Multiple colors of high quality may be achieved by the present invention.

Claims

1. A display fluid comprising a first type of pigment particles which is white and a second type of pigment particles which is colored, and said two types of pigment particles are oppositely charged and dispersed in a black solvent, wherein said black solvent comprises non-charged or slightly charged black particles dispersed in a clear and colorless solvent.

2. The fluid of claim 1, wherein said second type of pigment particles is non-white and non-black.

3. The fluid of claim 1, wherein said second type of pigment particles is red, green, blue, cyan, magenta or yellow.

4. The fluid of claim 1, wherein said second type of pigment particles is red, green or blue.

5. The fluid of claim 1, wherein said non-charged or slightly charged black particles are substantially transparent.

6. The fluid of claim 1, wherein the non-charged or slightly charged black particles have a size of less than 100 nanometers.

7. The fluid of claim 1, wherein the non-charged or slightly charged black particles have a zeta potential of <

20.

8. The fluid of claim 1, wherein the non-charged or slightly charged black particles are polymeric and in the form of a transparent polymeric matrix, with dye molecules embedded in the matrix.

9. A display device comprising the display fluid of claim 1, wherein said fluid is sandwiched between a first layer comprising a common electrode and a second layer comprising pixel electrodes.

10. A display fluid comprising a first type of pigment particles which is white and a second type of pigment particles which is colored and said two types of pigment particles are oppositely charged and dispersed in a colored solvent, wherein the colored solvent comprises non-charged or slightly charged colored particles dispersed in a clear and colorless solvent and the color of the non-charged or slightly charged colored particles is complementary to the color of the second type of pigment particles.

11. The fluid of claim 10, the second type of pigment particles dispersed in the colored solvent gives the appearance of a black color.

12. The fluid of claim 10, wherein said second type of pigment particles is non-white and non-black.

13. The fluid of claim 10, wherein said second type of pigment particles is red, green, blue, cyan, magenta or yellow.

14. The fluid of claim 10, wherein said second type of pigment particles is red, green or blue.

15. The fluid of claim 10, wherein said non-charged or slightly charged colored particles are substantially transparent.

16. The fluid of claim 10, wherein said non-charged or slightly charged colored particles have a size of less than 100 nanometers.

17. The fluid of claim 10, wherein the non-charged or slightly charged colored particles have a zeta potential of <

20.

18. The fluid of claim 10, wherein the non-charged or slightly charged colored particles are polymeric and in the form of a transparent polymeric matrix, with dye molecules embedded in the matrix.

19. A display device comprising the display fluid of claim 10, wherein said fluid is sandwiched between a first layer comprising a common electrode and a second layer comprising pixel electrodes.

20. A display device which comprises a display fluid of claim 10 and said fluid is sandwiched between a first layer comprising a common electrode and a second layer comprising pixel electrodes and in-plane electrodes.