Dielectrophoretic displays

• US 8,305,341 B2
• Filed: 08/28/2009
• Issued: 11/06/2012
• Est. Priority Date: 07/20/1995
• Status: Expired due to Fees

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Arango, Alexi C., Jacobson, Joseph M., Amundson, Karl R.
• Primary Examiner(s): GIESY, ADAM
• Application Number:
  US12/549,763
• Publication Number:
  US 20100045592A1
• Time in Patent Office: 1,166 Days
• Field of Search: 345/107
• US Class Current: 345/107
• CPC Class Codes: B41J 2/01 Ink jet
• CPC Class Codes: B41J 2/02 generating a continuous ink jet
• CPC Class Codes: B41J 3/4076 printing on rewritable, bistable "electronic paper" by a focused electric or magnetic field
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C09D 11/30 Inkjet printing inks
• CPC Class Codes: C09D 11/50 Sympathetic, colour changing or similar inks
• 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 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• 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 1/1365 in which the switching element is a two-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16762 having three or more electrodes per pixel
• CPC Class Codes: G02F 1/172 : based on a suspension of orientable dipolar particles, e.g. suspended particles displays
• CPC Class Codes: G02F 2202/12 : photoconductor
• CPC Class Codes: G02F 2202/28 : Adhesive materials or arrangements
• CPC Class Codes: G04B 47/00 : Time-pieces combined with other articles which do not interfere with the running or the time-keeping of the time-piece clockwork cases for special purposes G04B37/12; clocks with magnifying glass built in the face G04B39/00; time-pieces in which parts or cases produce special effects, e.g. aesthetic effects, G04B45/00, particularly with inscriptions or pictures moved by hand G04B45/003, with specially shaped cases or parts G04B45/0069; combination of writing or drawing implements with devices for indicating time B43K29/087; combined with cameras, projectors, or photographic printing apparatus G03B29/00
• CPC Class Codes: G06F 15/0283 : for data storage and retrieval
• 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: G09G 2310/0267 : Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• CPC Class Codes: G09G 2310/0275 : Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 2380/02 : Flexible displays
• CPC Class Codes: G09G 3/035 : for flexible display surfaces
• 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
• CPC Class Codes: G09G 3/38 : using electrochromic devices
• CPC Class Codes: H01L 27/12 : the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H05K 1/097 : Inks comprising nanoparticles and specially adapted for being sintered at low temperature H05K1/095 takes precedence
• CPC Class Codes: H05K 3/105 : by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam
• CPC Class Codes: H05K 3/1241 : by ink-jet printing or drawing by dispensing
• 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 19/00 : Integrated devices, or assemblies of multiple devices, comprising at least one organic element specially adapted for rectifying, amplifying, oscillating or switching, covered by group H10K10/00
• CPC Class Codes: H10K 85/113 : Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
• CPC Class Codes: H10K 85/114 : Poly-phenylenevinylene; Derivatives thereof
• CPC Class Codes: H10K 85/20 : Carbon compounds, e.g. carbon nanotubes or fullerenes
• CPC Class Codes: H10K 85/30 : Coordination compounds
• CPC Class Codes: H10K 85/311 : Phthalocyanine
• CPC Class Codes: H10K 85/60 : Organic compounds having low molecular weight H10K85/10 - H10K85/50 take precedence
• CPC Class Codes: H10K 85/611 : Charge transfer complexes
• CPC Class Codes: H10K 85/615 : Polycyclic condensed aromatic hydrocarbons, e.g. anthracene

Abstract

A dielectrophoretic display comprises a substrate having walls defining at least one cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface; a suspending fluid contained within the cavity; a plurality of at least one type of particle suspended within the suspending fluid; and means for applying to the fluid an electric field effective to cause dielectrophoretic movement of the particles to the side wall of the cavity.

Claims

1. A display comprising:

a substrate having walls defining at least one cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface;

a fluid contained within the cavity;

a plurality of at least one type of electrically charged solid particle within the fluid; and

means for applying to the fluid an electric field effective to cause movement of the particles to the side wall of the cavity.

2. A process for operating a display, the process comprising:

providing a substrate having walls defining at least one cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface;

a fluid contained within the cavity;

and a plurality of at least one type of electrically charged solid particle within the fluid; and

applying to the fluid an electric field effective to cause movement of the solid particles to the side wall of the cavity.

3. A display comprising:

a substrate having walls defining at least one cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface;

a fluid contained within the cavity;

a plurality of at least one type of electrically charged solid particle within the fluid, the solid particles having a first optical characteristic;

a backing member disposed on the opposed side of the cavity from the viewing surface, at least part of the backing member having a second optical characteristic different from the first optical characteristics, the backing member being light-transmissive; and

means for applying to the substrate an electric field effective to cause movement of the solid particles to the side wall of the cavity.

4. A display according to claim 3 wherein the cavity has a non-circular cross-section as seen from the viewing surface.

5. A display according to claim 4 wherein the cavity has a polygonal cross-section as seen from the viewing surface.

6. A display according to claim 3 having a single type of solid particle formed from an electrically conductive material.

7. A display according to claim 6 wherein the single type of solid particle is formed from a metal or carbon black.

8. A display according to claim 3 having a single type of solid particle formed from a doped semiconductor.

9. A display according to claim 3 wherein the substrate comprises at least one capsule wall so that the display comprises at least one capsule.

10. A display according to claim 9 comprising a plurality of capsules, the capsules being arranged in a single layer.

11. A display according to claim 3 wherein the substrate comprises a continuous phase surrounding a plurality of discrete droplets of the fluid having the at least one type of solid particle therein.

12. A display according to claim 3 wherein the substrate comprises a substantially rigid material having the at least one cavity formed therein, the substrate further comprising at least one cover member closing the at least one cavity.

13. A display according to claim 3 arranged to have light projected on to a surface on the opposed side of the display from the viewing surface.

14. A process for operating a display, the process comprising:

providing a substrate having walls defining at least one cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface, a fluid contained within the cavity;

and a plurality of at least one type of electrically charged solid particle within the fluid, the particles having a first optical characteristic; and

a backing member disposed on the opposed side of the cavity from the viewing surface, at least part of the backing member having a second optical characteristic different from the first optical characteristic, the backing member being light-transmissive; and

applying to the substrate an electric field effective to cause movement of the solid particles to the side wall of the cavity.

15. A process according to claim 14 wherein the electric field is an alternating electric field.

16. A process according to claim 14 having only a single type of solid particle formed from an electrically conductive material.

17. A process according to claim 16 wherein the electrically conductive material is a metal or carbon black.

18. A process according to claim 14 having only a single type of solid particle formed from a doped semiconductor.

19. A process according to claim 14 wherein the substrate comprises at least one capsule wall so that the display comprises at least one capsule.

20. A process according to claim 19 wherein the substrate comprises a plurality of capsules, the capsules being arranged in a single layer.

21. A process according to claim 14 wherein the substrate comprises a continuous phase surrounding a plurality of discrete droplets of the fluid having the solid particles suspended therein.

22. A process according to claim 14 wherein the substrate comprises a substantially rigid material having the at least one cavity formed therein, the substrate further comprising at least one cover member closing the at least one cavity.

23. A process for operating a display, the process comprising:

providing a substrate having walls defining at least one cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface, a fluid contained within the cavity;

and a plurality of solid particles within the fluid, the particles having a dielectric constant higher than the dielectric constant of the fluid; and

applying to the substrate a non-homogeneous electric field, the electric field being greater adjacent the side wall than in the center of the cavity, thereby causing the particles to move to the side wall of the cavity.

24. A process for operating a display, the process comprising:

providing a substrate having walls defining at least one cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface, a fluid contained within the cavity; and

a plurality of solid particles within the fluid, the particles having a dielectric constant lower than the dielectric constant of the fluid; and

applying to the substrate a non-homogeneous electric field, the electric field being smaller adjacent the side wall than in the center of the cavity, thereby causing the solid particles to move to the side wall of the cavity.

25. A display comprising:

a substrate having walls defining at least one cavity, the cavity having a viewing surface, a rear surface on the opposed side of the cavity from the viewing surface, and a side wall extending between the viewing surface and the rear surface;

a fluid contained within the cavity;

a plurality of at least one type of electrically charged solid particle within the fluid;

a front electrode adjacent the viewing surface of the cavity;

a rear electrode adjacent the rear surface; and

a side electrode adjacent the side wall,

the display having a first optical state in which the solid particles lie adjacent the front electrode, a second optical state in which the solid particles lie adjacent the rear electrode and a third optical state in which the solid particles lie adjacent the side electrode.

26. A display comprising:

a substrate having walls defining at least one cavity, the cavity having a viewing surface, a rear surface on the opposed side of the cavity from the viewing surface, and a side wall extending between the viewing surface and the rear surface;

a fluid contained within the cavity;

a plurality of at least one type of electrically charged solid particle within the fluid;

a front electrode adjacent the viewing surface of the cavity;

a rear electrode adjacent the rear surface; and

a side electrode adjacent the side wall,

the display having a first optical state in which the solid particles lie adjacent the viewing surface, a second optical state in which the solid particles lie adjacent the rear surface and a third optical state in which the solid particles lie adjacent the side wall.