Patent ID: 8115729

Claim:
An electrophoretic display element, the display element having a viewing surface and comprising at least one droplet of an electrophoretic phase and a wall surrounding the droplet, the droplet comprising: a fluid; a plurality of first particles disposed in the fluid and having a first optical characteristic and a first electrophoretic mobility; a plurality of second particles disposed in the fluid and having a second optical characteristic different from the first optical characteristic and a second electrophoretic mobility of opposite polarity to the first electrophoretic mobility; and a plurality of third particles disposed in the fluid and having a third optical characteristic different from the first and second optical characteristics, the third particles not undergoing electrophoretic motion in an electric field, the electrophoretic display element having a first display state in which the viewing surface displays the first optical characteristic, a second display state in which the viewing surface displays the second optical characteristic, and a third display state in which the viewing surface displays the third optical characteristic.