Display panel with pre-patterned images

• US 9,436,057 B2
• Filed: 09/15/2014
• Issued: 09/06/2016
• Est. Priority Date: 09/23/2013
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink California, LLC (E Ink Corporation)
• Inventors: Kang, Yih-Ming, Schultz, Donald A.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US14/486,994
• Publication Number:
  US 20150085345A1
• Time in Patent Office: 722 Days
• Field of Search: 359/296, 359/228, 359/245, 359/253, 345/84, 345/107, 438/106, 438/455, 438/488, 438/584, 438/589, 349/44, 349/74, 349/84, 349/95, 349/110, 427/58, 427/162, 427/164, 264/134
• US Class Current: 1/1
• CPC Class Codes: G02B 26/026 based on the rotation of particles under the influence of an external field, e.g. gyricons, twisting ball displays based on orientable dipolar particles G02F1/172; based on electrophoresis G02F1/167
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1679 Gaskets; Spacers; Sealing of cells; Filling or closing of cells
• CPC Class Codes: G02F 1/1681 having two or more microcells partitioned by walls, e.g. of microcup type
• 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 display panel comprising micro-containers filled with an electrophoretic fluid wherein each of the microcells has a bottom and one surface of the bottom is in contact with the electrophoretic fluid, the display panel has a first area and a second area, and the microcells in the first area have substantially the same bottom thickness and the microcells in the second area have added bottom thicknesses. Such a display panel is useful for many applications, such as bar codes, anti-counterfeiting labels, direction signages, shelf labels or watermarks.

Claims

1. A display panel comprising microcells filled with an electrophoretic fluid, wherein:

each of the microcells has a bottom and an inner surface of the bottom is in contact with the electrophoretic fluid, the display panel has a first area and a second area, the microcells in the first area have substantially the same bottom thickness, and the microcells in the second area have thicker bottom than the microcells in the first area.

2. The panel of claim 1, wherein the microcells in the second area have a bottom thickness which is 0.001 micron to 9/10 of the depth of the microcells in the first area, more than the bottom thickness of the microcells in the first area.

3. The panel of claim 1, wherein the microcells in the second area have a bottom thickness which is 0.001 micron to ½

of the depth of the microcells in the first area, more than the bottom thickness of the microcells in the first area.

4. The panel of claim 1, wherein the bottom thicknesses of the microcells in the second area are not the same.

5. The panel of claim 1, wherein an electrophoretic fluid filled in the microcells in both the first and second areas comprises one type of charged particles dispersed in a solvent or solvent mixture.

6. The panel of claim 1, wherein an electrophoretic fluid filled in the microcells in the first and second areas comprises two types of charged particles dispersed in a solvent or solvent mixture.

7. The panel of claim 1, wherein an electrophoretic fluid filled in the microcells in the first and second areas comprises more than two types of charged particles dispersed in a solvent or solvent mixture.

8. The panel of claim 1, which is sandwiched between two electrode layers.

9. The panel of claim 8, wherein the two electrode layers are non-patterned conductive layers.

10. The panel of claim 8, wherein one of the electrode layers is a common electrode layer and the other electrode layer is a thin-film-transistor matrix driving system or segmented backplane driving system.

11. A method for preparing a display panel of claim 1, comprising:

a) providing a nip roller on the surface of which has carved-out areas to form a pattern which pattern is a positive or negative image of an intended pattern for the display panel;

b) coating an embossable composition over a substrate layer which is on the surface of the nip roller; and

c) applying a male mold over the embossable composition.

12. The method of claim 11, wherein the carved-out areas have different depths.

13. The method of claim 11, wherein said substrate layer is attached to an electrode layer.

14. A method for preparing a display panel of claim 1, comprising:

a) providing microcells;

b) filling the microcells in a pre-determined area, with a chemical composition in a solvent;

c) removing the solvent; and

d) optionally curing the chemical composition after removal of the solvent.

15. The method of claim 14, wherein the solvent is methyl ethyl ketone, acetone, or isopropyl alcohol.

16. The method of claim 14, wherein the microcells are filled with different concentrations of chemical compositions.

17. The method of claim 16, wherein the concentrations are in the range of 0.01% to 90% by weight.

18. The method of claim 16, wherein the concentrations are in the range of 0.01% to 50% by weight.

19. The method of claim 14, wherein the chemical composition is not the same as a composition from which the microcells are formed.

20. The method of claim 14, wherein the chemical composition is the same as a composition from which the microcells are formed.