Method of forming an electro-optic medium

Patent metadata

Field	Value
Publication number	US-2021002488-A1
Application number	US-202017023687-A
Country	US
Kind code	A1
Filing date	Sep 17, 2020
Priority date	Jun 16, 2017
Publication date	Jan 7, 2021
Grant date	—

Abstract

A variable transmission film may include an electrophoretic medium having a plurality of capsules and a binder, each capsule containing a plurality of electrically charged particles and a fluid, the charged particles being movable by application of an electric field and being capable of being switched between an open state and a closed state. The film may include at least one of a binder containing fish gelatin and a polyanion; a binder containing one or more tinting agents; capsules containing charge control agents, such as an oligoamine-terminated polyolefin and a branched chain fatty acid comprising at least 8 carbon atoms; a selection of capsules in which at least 60% have a diameter between 50 μm and 90 μm and at least 15% have a diameter between 20 μm and 49 μm; a tinted adhesive layer; and a fluid selected from one or more nonconjugated olefinic hydrocarbons.

First claim

We claim:

1 . A method of forming an electro-optic medium comprising:
providing an internal phase mixture of a non-polar solvent and charged pigment particles, encapsulating portions of the internal phase mixture in a plurality of capsules, sieving the plurality of capsules into at least two portions, a first portion comprising capsules having a size distribution between 50 μm and 90 μm in diameter, and a second portion comprising capsules having a size distribution between 20 μm and 49 μm in diameter, and mixing a polymeric binder with two to five parts by weight of the first portion and one part by weight of the second portion.

2 . The method of forming an electro-optic medium of claim 1 , wherein the polymeric binder is mixed with capsules at least 60% in a size range of between 50 μm and 90 μm in diameter and at least 15% in a size range of between 20 μm and 49 μm in diameter.

3 . The method of forming an electro-optic medium of claim 1 , wherein the binder further comprises a tinting agent comprising one or more types of colored pigment particles selected from the group consisting of black, cyan, yellow, magenta particles, and combinations thereof.

4 . The method of forming an electro-optic medium of claim 3 , wherein the black, cyan, and magenta particles have an average diameter within a range of 20 nm and 100 nm.

5 . The method of forming an electro-optic medium of claim 3 , wherein the tinting agent comprises a mass ratio of black to cyan particles of 10:1 to 3:2, and a mass ratio of black to magenta particles of 10:1 to 3:2.

6 . The method of forming an electro-optic medium of claim 3 , wherein the tinting agent comprises carbon black.

7 . A variable transmission film comprising:
a layer of an electrophoretic medium comprising a plurality of capsules and a binder, each capsule containing a plurality of electrically charged particles and a fluid, the charged particles being movable by application of an electric field and capable of being switched between an open state and a closed state; a layer of adhesive comprising a tinting agent; and two light-transmissive electrodes, wherein the layer of electrophoretic medium and the layer of adhesive are disposed between the two light-transmissive electrodes.

8 . The variable transmission film of claim 7 , wherein the tinting agent is selected from the group consisting of a dye and a pigment.

9 . The variable transmission film of claim 7 , wherein the tinting agent comprises a soluble dye.

10 . The variable transmission film of claim 7 , wherein the tinting agent comprises carbon black.

11 . The variable transmission film of claim 7 , wherein the tinting agent comprises one or more types of colored pigment particles selected from the group consisting of black, cyan, yellow, magenta particles, and combinations thereof.

12 . The variable transmission film of claim 11 , wherein the black, cyan, and magenta particles have an average diameter within a range of 20 and 100 nm.

13 . The variable transmission electro-optic medium of claim 11 , wherein the tinting agent comprises a mass ratio of black to cyan particles of 10:1 to 3:2, and a mass ratio of black to magenta particles of 10:1 to 3:2.

14 . The variable transmission film of claim 7 , wherein the layer of adhesive has a transmission greater than the transmission of the layer of electrophoretic medium in the closed state and less than the transmission of the layer of electrophoretic medium in the open state.

Assignees

• E Ink Corp

Inventors

• Widger Peter Carsten Bailey
• Anseth Jay William
• Paolini Jr Richard J
• Romanowsky Mark Benjamin
• Smith Jillian
• Telfer Stephen J
• Breen Craig Alan
• Bull Stephen

Classifications

• G02F1/1675

  Constructional details · CPC title

• G02F1/1676

  Electrodes · CPC title

• G02F1/16757 Primary

  Microcapsules · CPC title

• G02F1/167 Primary

  by electrophoresis · CPC title

• G02F2001/1678

  characterised by the composition or particle type · CPC title