Non-spherical cavity electrophoretic displays and materials for making the same

• US 6,392,785 B1
• Filed: 01/28/2000
• Issued: 05/21/2002
• Est. Priority Date: 08/28/1997
• Status: Expired due to Term

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Inventors: Albert, Jonathan D., Comiskey, Barrett
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/493,635
• Time in Patent Office: 844 Days
• Field of Search: 359/296, 359/452, 345/107, 345/108, 345/84, 264/4, 264/8, 264/4.1, 204/606, 204/450, 204/487, 427/213.3, 427/213.31
• 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. An encapsulated electrophoretic display having a viewed surface and a rear surface, comprising a polymer matrix having fluid-containing cavities, wherein said cavities are non-spherical in shape and an aspect ratio of width to height for said cavities is greater than about 1.2.

2. The display of claim 1, wherein said aspect ratio is greater than about 1.5.

3. The display of claim 2, wherein said aspect ratio is greater than about 1.75.

4. The display of claim 1, wherein said viewed surface is substantially planar.

5. The display of claim 1, wherein both said viewed surface and said rear surface are substantially planar.

6. The display of claim 1, wherein said fluid-containing cavities are elastomeric capsules.

7. The display of claim 1, wherein said fluid comprises an oil.

8. An encapsulated electrophoretic display having a viewed surface and a rear surface, comprising a polymer matrix having fluid-containing cavities, wherein said cavities are non-spherical in shape and a volume fraction of said polymer matrix is between about 0.0 to about 0.9.

9. The display of claim 8, wherein said volume fraction is between about 0.05 to about 0.2.

10. The display of claim 8, wherein said viewed surface is substantially planar.

11. The display of claim 8, wherein both said viewed surface and said rear surface are substantially planar.

12. The display of claim 8, wherein said fluid-containing cavities are elastomeric capsules.

13. The display of claim 8, wherein said fluid comprises an oil.

14. An encapsulated electrophoretic display having a viewed surface and a rear surface, comprising a polymer matrix having fluid-containing cavities, wherein said cavities are non-spherical in shape and have an optically active fraction of said viewed surface is greater than about 80%.

15. The display of claim 14, wherein said optically active fraction is greater than about 90%.

16. The display of claim 14, wherein said fluid-containing cavities are elastomeric capsules.

17. The display of claim 14, wherein said fluid comprises an oil.

18. The display of claim 14, wherein said viewed surface is substantially planar.

19. The display of claim 14, wherein both said viewed surface and said rear surface are substantially planar.