Electronic paper display device, manufacturing method and driving method thereof

• US 7,751,115 B2
• Filed: 08/25/2006
• Issued: 07/06/2010
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Song, Moon Bong
• Primary Examiner(s): Spector; David N
• Application Number:
  US11/509,678
• Publication Number:
  US 20070046623A1
• Time in Patent Office: 1,411 Days
• Field of Search: 345/345, 345/107, 359/296
• US Class Current: 359/296
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1676 Electrodes
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• 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

An electronic paper display device, a manufacturing method and a driving method thereof are disclosed. Micro protrusion members are formed at electrodes or at insulating layers. Consequently, the electrophoretic particles are prevented from being securely attached to an upper or the lower structure, and therefore, the quality of pictures is improved, and the contrast ratio of the pictures is increased. The relative sizes and the injection amounts of two kinds of electrophoretic particles are changed such that the relative sizes and the injection amounts of the electrophoretic particles are different from each other. Consequently, the driving voltage is lowered by excessively electrifying the electrophoretic particles of one kind. Protrusions are formed at the corresponding electrode such that a relatively large electric field is distributed around the electrode at which electrophoretic particles are located in the initial stage of voltage application. Consequently, the electrophoretic particles are easily separated from the electrode and moved even at low driving voltage. As such, the voltage level of the driving voltage pulse is lowered. Consequently, it is possible to further increase the response speed of the driving devices and to lower the internal voltage of the devices, thereby reducing the costs related to the driving devices.

Claims

1. An electronic paper display device comprising:

a first substrate and a second substrate, which are disposed opposite to each other while the first substrate and the second substrate are spaced apart from each other;

a plurality of first electrodes and a plurality of second electrodes formed at the bottom of the first substrate and at the top of the second substrate, respectively;

a plurality of barrier ribs disposed between the first substrate and the second substrate to form a plurality of cells;

electrophoretic particles injected in the cells; and

a micro protrusion member formed at the bottom of each first electrode and/or at the top of each second electrode.

2. The electronic paper display device according to claim 1, wherein micro protrusion member is made of an insulating material.

3. The electronic paper display device according to claim 1, further comprising:

a first insulating layer disposed between each first electrode and the first micro protrusion member formed at the bottom of each first electrode.

4. The electronic paper display device according to claim 1, further comprising:

a second insulating layer disposed between each second electrode and the second micro protrusion member formed at the top of each second electrode.

5. The electronic paper display device according to claim 1, wherein the micro protrusion member is formed by applying micro particles having a size of 0.1 to 0.01 times the size of the electrophoretic particles.

6. The electronic paper display device according to claim 1, wherein the micro protrusion member is formed by applying micro particles having a size of 10 nm to 10 μ

m.

7. The electronic paper display device according to claim 1, wherein the micro protrusion member has a thickness of 10 nm to 10 μ

m.

8. The electronic paper display device according to claim 1, wherein the micro protrusion member is constructed in a hemispherical protrusion shape, a pyramidal protrusion shape, in a conical protrusion shape, in a prismatic protrusion shape, in a cylindrical protrusion shape, or in a combination thereof.

9. The electronic paper display device according to claim 1, wherein the micro protrusion member contains polymer or inorganic oxide.

10. The electronic paper display device according to claim 9, wherein the polymer is polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyimide (PI), or polystyrene (PS).

11. The electronic paper display device according to claim 9, wherein the inorganic oxide is silicon dioxide (SiO₂), titanium dioxide (TiO₂), aluminum oxide (Al₂O₃), or zinc oxide (ZnO).

12. A manufacturing method of an electronic paper display device, comprising:

manufacturing a first structure, including forming a first electrode at the bottom of a first substrate and forming a first micro protrusion member at the bottom of the first electrode;

manufacturing a second structure, including forming a second electrode at the top of a second substrate and forming a second micro protrusion member at the top of the second electrode;

manufacturing barrier ribs at the top of the second structure to form cell spaces;

injecting electrophoretic particles into the cell spaces to display pictures; and

stacking and attaching the first structure and the second structure having the barrier ribs to each other.

13. The manufacturing method according to claim 12, further comprising:

forming a first insulating layer between the first electrode and the first micro protrusion member.

14. The manufacturing method according to claim 12, further comprising:

forming a second insulating layer between the second electrode and the second micro protrusion member.

15. The manufacturing method according to claim 12, wherein the micro protrusion members are formed in a hemispherical shape, in a pyramidal shape, in a conical shape, in a prismatic shape, in a cylindrical shape, or in a combination thereof.

16. The manufacturing method according to claim 12, wherein the electrophoretic particles are dry-type electrophoretic particles.

17. The manufacturing method according to claim 12, wherein first and second electrophoretic particles are injected into the cells while the particle amounts and the particle diameters of the first and second electrophoretic particles are different from each other.

18. The manufacturing method according to claim 12, wherein the micro protrusion members are integrally formed with the first electrode or the second electrode.

19. The manufacturing method according to claim 18, wherein the micro protrusion members are formed by etching the first electrode or the second electrode using dry-type etching or wet-type etching.

20. The manufacturing method according to claim 18, wherein the micro protrusion members are formed in a hemispherical shape, in a pyramidal shape, in a conical shape, in a prismatic shape, in a cylindrical shape, or in a combination thereof.

21. The manufacturing method according to claim 12, wherein the forming the micro protrusion members includes applying a material containing organic polymer or inorganic oxide micro particles having a size of 0.1 to 0.01 times the size of the electrophoretic particles.

22. The manufacturing method according to claim 21, wherein the forming the micro protrusion members is carried out using photolithography after applying the organic polymer or the inorganic oxide.

23. The manufacturing method according to claim 21, wherein the forming the micro protrusion members is carried out using a mold having predetermined micro grooves after applying the organic polymer or the inorganic oxide.

24. The manufacturing method according to claim 21, wherein the polymer is polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyimide (PI), or polystyrene (PS).

25. The manufacturing method according to claim 21, wherein the inorganic oxide is silicon dioxide (SiO₂), titanium dioxide (TiO₂), aluminum oxide (Al₂O₃), or zinc oxide (ZnO).