Patent ID: 8031392

Claim:
A display device comprising: an electrophoretic display element comprising, a plurality of types of particles enclosed between a pair of substrates, at least one of the substrates being translucent and each of the respective plurality of types of particles being charged with the same polarity, differing in optical properties, and differing in either in migration speed and/or electric field threshold value for moving, a translucent display-side electrode provided at the substrate side where the translucent substrate is disposed, a first back-side electrode provided at the side of the other substrate, facing the display-side electrode, and a second back-side electrode provided at the side of the other substrate, facing the display-side electrode; and a voltage control section that controls the voltages applied to the display-side electrode, the first back-side electrode, and the second back-side electrode, wherein the plurality of types of particles includes at least three different types of electrophoretic particles, wherein all three different types of electrophoretic particles are charged with the same polarity, have differing optical properties and differ in either in migration speed and/or electric field threshold value for moving, wherein the at least three different types of electrophoretic particles comprise: a first type of electrophoretic particles having a fastest migration speed or a lowest threshold value for moving, from among the at least three different types of electrophoretic particles; a second type of electrophoretic particles having a slower migration speed or a higher threshold value for moving, than the first type of electrophoretic particles; and a third type of electrophoretic particles having a slower migration speed or a higher threshold value for moving, than the second type of electrophoretic particles, wherein the voltage control section first controls a reset state to be achieved wherein each of the three different types of electrophoretic particles are moved toward the display-side electrode, and wherein the voltage control section then controls the first type of electrophoretic particles and the third type of electrophoretic particles to contribute to a color of the electrophoretic display element by: moving the first type of electrophoretic particles toward the first back-side electrode; then moving the second type of electrophoretic particles toward the second back-side electrode; then moving the third type of electrophoretic particles toward the first back-side electrode; and then moving the first type of electrophoretic particles and the third type of electrophoretic particles toward the display-side electrode while the second type of electrophoretic particles remain at the second back-side electrode.