Electrophoretic display device and operating method of the same
An electrophoretic display device with high reliability, high reflectance and improved color characteristics. The electrophorectic display device includes unit cells, each of which includes transmissive particles and a reflective panel. The unit cells are vertically laminated or arranged in parallel. In addition, the electrophorectic display device exhibits excellent visibility and has a simple structure.
1. An electrophoretic display device comprising:
unit cells divided by partitions, each of the unit cells comprising:
an upper panel including a transparent substrate and a second electrode formed over the entire surface of the transparent substrate of the upper panel;
a lower panel disposed opposite to the upper panel and including a transparent substrate and first electrodes formed at edges of the transparent substrate of the lower panel;
counter electrodes disposed under respective first electrodes and having a smaller size than the first electrodes;
a reflective panel positioned under the lower panel; and
a plurality of charged transmissive colored particles dispersed in a fluid accommodated between the upper and lower panels.
2. The electrophoretic display device of claim 1 , wherein each of the unit cells comprises a one-cell two-color type which includes different types of transmissive particles charged with different polarities.
3. The electrophoretic display device of claim 1 , wherein the reflective panel is configured to be detachable from the electrophoretic display device.
4. The electrophoretic display device of claim 3 , wherein the reflective panel is made of paper, cloth or plastic.
5. The electrophoretic display device of claim 1 , wherein the electrophoretic display device is of a transmissive type.
6. The electrophoretic display device of claim 1 , wherein the width of the counter electrodes is at least 10 μm smaller than a width of the first electrodes.
7. The electrophoretic display device of claim 1 , wherein two unit cells are vertically laminated.
8. The electrophoretic display device of claim 7 , wherein the vertically laminated unit cells include two one-cell two-color type unit cells.
9. The electrophoretic display device of claim 7 , wherein one of the upper and lower layers of the laminated unit cells is a one-cell one-color type unit cell.
10. The electrophoretic display device of claim 7 , wherein the laminated unit cells includes two one-cell one-color type unit cells arranged parallel to each other and one common one-cell one-color unit cell vertically laminated thereon.
11. The electrophoretic display device of claim 7 , wherein the laminated unit cells includes two one-cell one-color type unit cells arranged parallel to each other and two one-cell one-color type unit cells vertically laminated on the respective previous unit cells.
12. The electrophoretic display device of claim 1 , wherein the electrophoretic display device includes two unit cells including two one-cell two-color type unit cells arranged parallel to each other.
13. The electrophoretic display device of claim 12 , wherein one of the two unit cells is of a one-cell one-color type.
14. The electrophoretic display device of claim 1 , wherein a color of the transmissive charged particles is selected from cyan, magenta and yellow.
15. The electrophoretic display device of claim 14 , wherein the color of the transmissive charged particles is selected from cyan, magenta, yellow, red, green and blue.
16. The electrophoretic display device of claim 8 , wherein one of four colors of the two unit cells is black.
17. The electrophoretic display device of claim 12 , wherein one of four colors of the two unit cells is black.
18. A method for operating an electrophoretic display device comprising unit cells divided by partitions, each of the unit cells including an upper panel having a transparent substrate and a second electrode formed over the entire surface of the transparent substrate of the upper panel, a lower panel disposed opposite to the upper panel and having a transparent substrate and first electrodes formed at edges of the transparent substrate of the lower panel, counter electrodes disposed under respective first electrodes and having a smaller size than the first electrodes, a reflective panel positioned under the lower panel, and a plurality of charged transmissive colored particles dispersed in a fluid accommodated between the upper and lower panels, the method comprising:
uniformly dispersing the charged transmissive colored particles in the fluid to create a color; and
collecting the dispersed transmissive particles on the first electrodes to erase the color.
19. The method of claim 18 , wherein the collected transmissive particles are uniformly distributed in the fluid by applying an alternating current or pulsed signals between the first electrodes or between the first and second electrodes.