Color display device

Patent metadata

Field	Value
Publication number	US-9541814-B2
Application number	US-201514626552-A
Country	US
Kind code	B2
Filing date	Feb 19, 2015
Priority date	Feb 19, 2014
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

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.

First claim

What is claimed is:

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 at the non-viewing side; the electrophoretic fluid 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; and
wherein application, to a pixel, of a mid-driving voltage causes a mixture of the particles of the first type and second type to stay in middle of the pixel and causes the particles of the third type to break away from the mixture and move at or near the viewing side; and
wherein the application of the mid-driving voltage further causes the particles of the fifth type to break away from the mixture and move at or near the pixel electrode.

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.

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 at the non-viewing side; the electrophoretic fluid 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 first 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, wherein the first high driving voltage causes the particles of the third type to stay near the viewing side and below the particles of the first type and causes the particles of the fourth type to stay near the viewing side and below the particles of the third type;
(ii) application, to a pixel, of a second 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, wherein the second high driving voltage causes the particles of the fifth type to stay near the viewing side and below the particles of the second type;
(iii) application, to a pixel, of a first 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, wherein the particles of the first, second and third types stay in middle of the pixel in a mixed state as the first low driving voltage is not strong enough to overcome attraction forces between the particles of the first, second and third; and
(iv) application, to a pixel, of a second 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, wherein the particles of the first, second and third types stay in middle of the pixel in a mixed state as the second low driving voltage is not strong enough to overcome attraction forces between the particles of the first, second and third.

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.

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 12 , 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 t

Assignees

• E Ink California Llc

Inventors

• Lin Craig
• Wang Ming
• Du Hui
• Zhang Xiaojia
• Li Yu
• Ivanov Roman
• Chen Yajuan

Classifications

• G09G3/344

  based on particles moving in a fluid or in a gas, e.g. electrophoretic devices (electrophoretic devices per se G02F1/167) · CPC title

• G02F1/13306

  Circuit arrangements or driving methods for the control of single liquid crystal cells (G02F1/132, G02F1/133382 take precedence) · CPC title

• G02F2001/1678

  characterised by the composition or particle type · CPC title

• G09G3/2003

  Display of colours (specific for liquid crystal displays G09G3/3607) · CPC title

• G02F1/167 Primary

  by electrophoresis · CPC title