Materials for use in electrophoretic displays

Patent metadata

Field	Value
Publication number	US-9310661-B2
Application number	US-90517110-A
Country	US
Kind code	B2
Filing date	Oct 15, 2010
Priority date	Mar 6, 2007
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

An electrophoretic medium comprises an electrophoretic layer, a layer of lamination adhesive and a polymeric layer disposed between the electrophoretic layer and the lamination adhesive layer, the polymeric layer being impermeable to the fluid. A second form of electrophoretic medium has a layer of a complex of an alkali metal and a polymer in contact with the electrophoretic layer. A third form of electrophoretic medium comprises a plurality of discrete droplets of internal phase in a binder, and further comprises a salt.

First claim

The invention claimed is:

1. A polymer-dispersed electrophoretic medium comprising a plurality of discrete droplets of an internal phase in a binder, the internal phase comprising a plurality of particles disposed in a fluid, the particles being capable of moving through the fluid upon application of an electric field to the medium, the binder comprising a poly(vinyl alcohol), polyvinylpyrrolidone, gelatin, and a salt.

2. An electrophoretic medium according to claim 1 wherein the electrophoretic layer is of the capsule-based type, with each of the droplets of internal phase being surrounded by a capsule wall, which is in turn surrounded by the binder.

3. An electrophoretic medium according to claim 1 wherein the electrophoretic layer is of the polymer-dispersed type, with the droplets of internal phase being in direct contact with the binder.

4. An electrophoretic medium according to claim 1 wherein the electrophoretic layer is of the microcell type with the droplets confined within cavities formed in a polymeric binder medium, which forms the walls of the microcells.

5. An electrophoretic medium according to claim 1 wherein the fluid is gaseous.

6. An electrophoretic medium according to claim 1 wherein the salt is a tetraalkylammonium salt.

7. An electrophoretic medium according to claim 6 wherein the salt is tetrabutylammonium hexafluorophosphate.

8. An electrophoretic medium according to claim 1 wherein the salt is added to the binder in the form of solid crystals having an average diameter not greater than about 5 μm.

9. An electrophoretic medium according to claim 8 wherein the salt is added to the binder in an amount of from about 5 to about 500 μmole per kilogram of binder, measured on a solids basis.

10. An electrophoretic display comprising an electrophoretic medium according to claim 1 and at least one electrode arranged to apply an electric field to the electrophoretic medium.

11. A front plane laminate comprising in order: a light-transmissive electrically-conductive layer; a layer of a solid electrophoretic medium in electrical contact with the electrically-conductive layer; an adhesive layer; and a release sheet, wherein the electrophoretic medium comprises a medium according to claim 1 .

12. A double release film comprising:
a layer of a solid electrophoretic medium comprising a binder and having first and second surfaces on opposed sides thereof;
a first adhesive layer on the first surface of the layer of electro-optic medium;
a release sheet disposed on the opposed side of the first adhesive layer from the layer of electro-optic medium; and
a second adhesive layer on the second surface of the layer of electro-optic medium,
wherein the electrophoretic medium comprises a medium according to claim 1 .

13. An inverted front plane laminate for use in forming an electrophoretic display, the article of manufacture comprising, in order:
at least one of a light-transmissive protective layer and a light-transmissive electrically-conductive layer;
an adhesive layer;
a layer of a solid electrophoretic medium comprising a binder; and
a release sheet,
wherein the electrophoretic medium comprises an electrophoretic medium according to claim 1 .

14. An electronic book reader, portable computer, tablet computer, cellular telephone, smart card, sign, watch, shelf label or flash drive comprising a display according to claim 10 .

Assignees

• Wu Bin
• Honeyman Charles Howie
• Dudek Stephen P
• Zalesky Anthony
• Paolini Jr Richard J
• Herb Craig A
• Harris George G
• E Ink Corp

Inventors

• Wu Bin
• Honeyman Charles Howie
• Dudek Stephen P
• Zalesky Anthony
• Paolini Jr Richard J
• Herb Craig A
• Harris George G

Classifications

• G02F1/167 Primary

  by electrophoresis · CPC title

• G02F2001/1678

  characterised by the composition or particle type · CPC title

• G02F1/16756

  Insulating layers · CPC title