Methods for driving electrophoretic displays using dielectrophoretic forces

Patent metadata

Field	Value
Publication number	US-11250794-B2
Application number	US-201615204096-A
Country	US
Kind code	B2
Filing date	Jul 7, 2016
Priority date	Jul 27, 2004
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

A dielectrophoretic display is shifted from a low frequency closed state to a high frequency open state via at least one, and preferably several, intermediate frequency states; the use of such multiple frequency steps reduces flicker during the transition. A second type of dielectrophoretic display has a light-transmissive electrode through which the dielectrophoretic medium can be viewed and a conductor connected to the light-transmissive electrode at several points to reduce voltage variations within the light-transmissive electrode.

First claim

The invention claimed is:

1. A dielectrophoretic display comprising:
a dielectrophoretic medium comprising a fluid and a plurality of at least one type of particle within the fluid, the particles being movable through the fluid on application of an electric field to the dielectrophoretic medium;
at least one light-transmissive electrode disposed adjacent the dielectrophoretic medium so that the dielectrophoretic medium can be viewed through the light-transmissive electrode; and
a conductor extending from the light-transmissive electrode to a voltage source, the conductor having a higher electrical conductivity than the light-transmissive electrode, the conductor contacting the light-transmissive electrode at at least two spaced points.

2. A dielectrophoretic display according to claim 1 wherein the dielectrophoretic medium and the light-transmissive electrode are rectangular and the conductor is arranged to contact the light-transmissive electrode substantially at the mid-point of each edge of the electrode.

3. A dielectrophoretic display according to claim 1 wherein the dielectrophoretic medium and the light-transmissive electrode are sufficiently large that, if the conductor was connected to the light-transmissive electrode at only a single point, there would be at least one point on the dielectrophoretic medium which was at least about 200 mm from said single point.

4. A dielectrophoretic display according to claim 1 wherein the conductor has the form of a conductive trace which extends around substantially the entire periphery of the light-transmissive electrode.

5. A dielectrophoretic display according to claim 1 wherein the conductor has a resistivity not greater than about 1 ohms/square.

6. A dielectrophoretic display according to claim 1 wherein the light-transmissive electrode comprises indium tin oxide.

7. A dielectrophoretic display according to claim 1 in the form of a variable transmission window having light-transmissive electrodes on both sides of the dielectrophoretic medium.

8. A light modulator, electronic book reader, portable computer, tablet computer, cellular telephone, smart card, sign, watch, shelf label or flash drive comprising a display according to claim 1 .

Assignees

• Harris George G
• Paolini Jr Richard J
• Whitesides Thomas H
• Mccreary Michael D
• Honeyman Charles Howie
• E Ink Corp

Inventors

• Harris George G
• Paolini Jr Richard J
• Whitesides Thomas H
• Mccreary Michael D
• Honeyman Charles Howie

Classifications

• G02F2202/42

  Materials having a particular dielectric constant · CPC title

• G02F1/1345

  Conductors connecting electrodes to cell terminals · CPC title

• G09G2320/0223

  Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes · CPC title

• G02F1/167

  by electrophoresis · CPC title

• G02F1/1676

  Electrodes · CPC title