Process for creating an encapsulated electrophoretic display

• US 6,067,185 A
• Filed: 08/27/1998
• Issued: 05/23/2000
• Est. Priority Date: 08/28/1997
• Status: Expired due to Term

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Albert, Jonathan D., Comiskey, Barrett
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/141,105
• Time in Patent Office: 635 Days
• Field of Search: 359/296, 359/317, 359/318, 359/237, 204/478, 204/606, 430/34, 430/35, 430/37, 430/56, 345/107, 345/100, 252/583, 264/5, 264/8
• US Class Current: 359/296
• CPC Class Codes: B41J 3/4076 printing on rewritable, bistable "electronic paper" by a focused electric or magnetic field
• 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 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133348 Charged particles addressed liquid crystal cells, e.g. controlled by an electron beam
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G02F 1/1345 Conductors connecting electrodes to cell terminals
• CPC Class Codes: G02F 1/135 Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied G02F1/133348 takes precedence
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16757 Microcapsules
• CPC Class Codes: G02F 2202/12 photoconductor
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: G06K 19/07703 the interface being visual
• CPC Class Codes: G09F 9/302 characterised by the form or geometrical disposition of the individual elements
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: H10K 10/46 Field-effect transistors, e.g. organic thin-film transistors [OTFT] H10K10/43 takes precedence
• CPC Class Codes: H10K 10/462 Insulated gate field-effect transistors [IGFETs]
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/60 Organic compounds having low molecular weight H10K85/10 - H10K85/50 take precedence

Abstract

Disclosed herein are novel electrophoretic displays and materials useful in fabricating such displays. In particular, novel encapsulated displays are disclosed. Particles encapsulated therein are dispersed within a suspending, or electrophoretic, fluid. This fluid may be a mixture of two or more fluids or may be a single fluid. The displays may further comprise particles dispersed in a suspending fluid, wherein the particles contain a liquid. In either case, the suspending fluid may have a density or refractive index substantially matched to that of the particles dispersed therein. Finally, also disclosed herein are electro-osmotic displays. These displays comprise at least one capsule containing either a cellulosic or gel-like internal phase and a liquid phase, or containing two or more immiscible fluids. Application of electric fields to any of the electrophoretic displays described herein affects an optical property of the display.

Claims

1. A process for creating an encapsulated electrophoretic display, comprising the steps of:

(a) providing a binder;

(b) curing said binder; and

(c) applying a mechanical force to said binder,

whereby application of the force causes said binder to form at least one capsule in a non-spherical shape.

2. The process of claim 1, wherein steps (b) and (c) occur simultaneously.

3. The process of claim 1, wherein said mechanical force is applied by an apparatus selected from the group consisting of rollers, a vacuum lamination press, and a mechanical press.

4. The process of claim 1, wherein said mechanical force causes the binder to stretch.

5. The process of claim 4 wherein the binder stretches along at least one axis.

6. The process of claim 4 wherein the binder stretches asymmetrically.

7. The process of claim 1 wherein the mechanical force comprises non-uniform shear.

8. The process of claim 1 wherein the mechanical force comprises compressive pressure.

9. A process for creating an encapsulated electrophoretic display, comprising the steps of:

(a) providing an evaporative binder; and

(b) curing said binder,

whereby said binder deforms as it cures causing the formation of at least one capsule in a non-spherical shape.

10. The process of claim 9, wherein said evaporative binder is selected from the group consisting of an acrylic, urethane, and poly(vinyl alcohol).

11. The process of claim 9 wherein the binder comprises an organic liquid.

12. The process of claim 9 wherein the binder comprises an aqueous liquid.

13. The process of claim 9 wherein the binder cures in stages.

14. The process of claim 9 wherein the binder shrinks while curing.

15. The process of claim 9 wherein the binder flattens while curing.