Patent ID: 7580025
Filing Date: 2009-08-25
Classification: G02F

Abstract:
1. An electrophoretic display device, comprising: a first substrate and a second substrate positioned to face each other; a first electrode mounted to the first substrate; a second electrode and a third electrode, which are positioned to face the first electrode, each of the second electrode and the third electrode having an area smaller than that of the first electrode, and the distance between the second electrode and the third electrode being set shorter than each of the distance between the second electrode and the first electrode and the distance between the third electrode and the first electrode; a suspension layer received in a space between the first electrode and each of the second and third electrodes, including insulating liquid medium and charged fine particles dispersed in the insulating liquid medium; an AC power source configured to apply a first AC voltage between the second electrode and the third electrode to produce a first AC electrical field between the second electrode and the third electrode, the AC electrical field generating a dielectrophoretic force to restrict movement of the charged fine particles to remain in a region between the second electrode and the third electrode; a DC power source configured to apply one of first and second DC voltages between the first electrode and each of the second and third electrodes to produce one of first and second DC electrical fields between the first electrode and each of the second and third electrodes; a switching part configured to switch the one of the first and second DC voltages to the other of the first and second DC voltages to change the one of the first and second DC electrical fields to the other of the first and second DC electrical fields, the first electrical field generating a first electrophoretic force to migrate the charged fine particles dispersed in the insulating liquid medium to be restricted to the region between the second and third electrodes so that a color of the first electrode, or a film on the first electrode, is observed, and the second electrical field generating a second electrophoretic force against the dielectrophoretic force to disperse the charged fine particles in the insulating liquid medium to disperse beyond the region between the second and third electrodes so that a color of the dispersed fine particles is observed.