COLOR DISPLAY DEVICE

• US 20150234250A1
• Filed: 02/19/2015
• Published: 08/20/2015
• Est. Priority Date: 02/19/2014
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink California, LLC (E Ink Corporation)
• Inventors: LIN, Craig, Wang, Ming, Du, Hui, Zhang, Xiaojia, Li, Yu, Ivanov, Roman, Chen, Yajuan
• Granted Patent: US 9,541,814 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1685 Operation of cells; Circuit arrangements affecting the entire cell
• CPC Class Codes: G02F 2001/1678 characterised by the composition or particle type
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167

Abstract

The present invention is directed to a color display device in which each pixel can display at least five high-quality color states, and an electrophoretic fluid for such an electrophoretic display. In one aspect, the different types of particles exhibit different levels of attraction force to display different color states. In another aspect, the different types of particles exhibit different levels of mobility in different driving voltage ranges to display different color states.

Claims

1. An electrophoretic display comprising a first surface on a viewing side, a second surface on a non-viewing side, and an electrophoretic fluid sandwiched between a common electrode at the viewing side and a layer of pixel electrodes and comprising a first type of particles, a second type of particles, a third type of particles, a fourth type of particles and a fifth type of particles, all of which are dispersed in a solvent or solvent mixture, wherein:

(a) the five types of pigment particles have optical characteristics differing from one another;

(b) the first and second types of particles carry opposite charge polarities;

(c) the third and fourth types of particles carry the same charge polarity as the first type of particles, and the first type, the third type and the fourth type of particles have progressively lower magnitudes; and

(d) the fifth type of particles carries the same charge polarity as the second type of particles, but their magnitude is lower than that of the second type of particles.

2. The display of claim 1, wherein the first and second types of particles are black and white, or vice versa.

3. The display of claim 1, wherein the first and second types of particles are black and yellow, or vice versa.

4. The display of claim 2, wherein the first type of particles is black, the second type of particles is white, and the third, fourth and fifth types of particles are red, green and blue, respectively.

5. The display of claim 3, wherein the first type of particles is black, the second type of particles is yellow, and the third, fourth and fifth types of particles are blue, red and white, respectively.

6. The display of claim 2, wherein the first type of particles is black, the second type of particles is white, and the third, fourth and fifth types of particles are red, yellow and blue, respectively.

7. The display of claim 2, wherein the first type of particles is white, the second type of particles is black, and the third, fourth and fifth types of particles are red, yellow and blue, respectively.

8. The display of claim 1, wherein the fluid further comprises non-charged or slightly charged neutral buoyancy particles.

9. The display of claim 8, wherein the neutral buoyancy particles are non-charged.

12. A driving method for driving an electrophoretic display of claim 1, the method comprises applying a driving voltage or a pulsing waveform of alternating a driving voltage and no driving voltage, to a pixel in the electrophoretic display, wherein the pixel is in the color state of the second type of particles and the driving voltage has the same polarity as the first, third and fourth types of particles to drive the pixel towards the color state of the fourth type of particles at the viewing side.

13. The method of claim 14, wherein the driving voltage is a low driving voltage.

14. A driving method for driving an electrophoretic display of claim 1, the method comprises applying a driving voltage or a pulsing waveform of a driving voltage and no driving voltage, to a pixel in the electrophoretic display, wherein the pixel is in the color state of the first type of particles and the driving voltage has the same polarity as the second and fifth types of particles to drive the pixel towards the color state of the fifth type of particles at the viewing side.

15. The method of claim 14, wherein the driving voltage is a low driving voltage.

16. A driving method for driving an electrophoretic display of claim 1, the method comprises applying a driving voltage or a pulsing waveform of alternating a driving voltage and no driving voltage, to a pixel in the electrophoretic display, wherein the pixel is in the color state of the fifth type of particles and the driving voltage has the same polarity as the first, third and fourth types of particles to drive the pixel towards the color state of the third type of particles at the viewing side.

17. The method of claim 16, wherein the driving voltage is a mid-driving voltage.

18. A driving method for driving an electrophoretic display of claim 1, the method comprises:

(i) applying, to a pixel, a high driving voltage having the same polarity as that of the first type of particles to cause the pixel to display the color of the first type of particles at the viewing side;

(ii) applying, to a pixel, a high driving voltage having the same polarity as that of the second type of particles to cause the pixel to display the color of the second type of particles at the viewing side;

(iii) applying, to a pixel, a low driving voltage having the same polarity as that of the fourth type of particles to cause the pixel to display the color of the fourth type of particles at the viewing side;

(iv) applying, to a pixel, a low driving voltage having the same polarity as that of the fifth type of particles to cause the pixel to display the color of the fifth type of particles at the viewing side; and

(v) applying, to a pixel, a mid-driving voltage having the same polarity as that of the third type of particles to cause the pixel to display the color of the third type of particles at the viewing side.

10. An electrophoretic display comprising a first surface on a viewing side, a second surface on a non-viewing side and an electrophoretic fluid sandwiched between a common electrode at the viewing side and a layer of pixel electrodes and comprising a first type of particles, a second type of particles, a third type of particles, a fourth type of particles and a fifth type of particles, all of which are dispersed in a solvent or solvent mixture, wherein:

(a) the five types of pigment particles have optical characteristics differing from one another;

(b) the first and second types of particles carry opposite charge polarities;

(c) the third and fourth types of particles carry the same charge polarity as the first type of particles, and the first type, the third type and the fourth type have progressively lower magnitudes; and

(d) the fifth type of particles carries the same charge polarity as the second type of particles, but their magnitude is lower than that of the second type of particles, and

(i) application, to a pixel, of a high driving voltage having the same polarity as that of the first type of particles causes the pixel to show the color of the first type of particles at the viewing side and have the second type of particles at or near the pixel electrode;

(ii) application, to a pixel, of a high driving voltage having the same polarity as that of the second type of particles causes the pixel to show the color of the second type of particles at the viewing side and have the first type of particles at or near the pixel electrode;

(iii) application, to a pixel, of a low driving voltage having the same polarity as that of the fourth type of particles causes the pixel to show the color of the fourth type of particles at the viewing side and have the fifth type of particles at or near the pixel electrode; and

(iv) application, to a pixel, of a low driving voltage having the same polarity as that of the fifth type of particles causes the pixel to show the color of the fifth type of particles at the viewing side and have the fourth type of particles at or near the pixel electrode.

11. The display of claim 10, further comprising

(v) application, to a pixel, of a mid-driving voltage having the same polarity as that of the third type of particles causes the pixel to show the color of the third type of particles at the viewing side and have the fifth type of particles or a mixture of the first, second and fifth types of particles, at or near the pixel electrode.

19. An electrophoretic display comprising a first surface on the viewing side, a second surface on the non-viewing side and an electrophoretic fluid which fluid is sandwiched between a common electrode and a layer of pixel electrodes and comprises a first type of particles, a second type of particles, a third type of particles, a fourth type of particles and a fifth type of, all of which are dispersed in a solvent or solvent mixture, wherein:

(a) the five types of pigment particles have optical characteristics differing from one another;

(b) the first and second types of particles carry opposite charge polarities; and

(c) the third, fourth and fifth types of particles carry the same charge polarity as the first type of particles and the first type, third type, fourth type and fifth type of particles have progressively lower magnitudes.

20. An electrophoretic display comprising a first surface on a viewing side, a second surface on a non-viewing side, and an electrophoretic fluid comprising five types of particles dispersed in a solvent or solvent mixture, wherein at least one of the five types of particles carries a charge polarity opposite the charge polarity carried by the remaining types of particles, and the different types of particles have different levels of mobility in different driving voltage ranges.