Display device

• US 8,031,392 B2
• Filed: 05/20/2010
• Issued: 10/04/2011
• Est. Priority Date: 12/09/2009
• Status: Active Grant

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Inventors: Machida, Yoshinori, Hiji, Naoki, Mizutani, Ryota, Abe, Masaaki
• Primary Examiner(s): Pinkney; Dawayne
• Application Number:
  US12/784,279
• Publication Number:
  US 20110134506A1
• Time in Patent Office: 502 Days
• Field of Search: 359/296, 430 31- 32, 345/107, 349/33
• US Class Current: 359/296
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 2001/1678 characterised by the composition or particle type
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters
• 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

Abstract

There is provided a display device including: an electrophoretic display element including, plural types of particles, each of the respective plural 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, a first back-side electrode, and a second back-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, such that the types of particles having the fastest migration speed from the plural types of particles, or the types of particles having the lowest threshold value from the plural types of particles, are moved to the first back-side electrode or to the second back-side electrode, and then the particles that moved to the first back-side electrode are moved to the display-side electrode.

Claims

1. 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.

2. The display device of claim 1 further comprising a partition wall provided between the first back-side electrode and the second back-side electrode, the partition wall having a height that is shorter than the separation distance between the substrates.

3. The display device of claim 1, wherein the voltage control section controls applying a voltage to the first back-side electrode to move the first type of electrophoretic particles and the third type of electrophoretic particles toward the first back-side electrode, and

wherein the voltage control section controls applying a voltage to the second back-side electrode to move the second type of electrophoretic particles remaining on the second back-side electrode toward the translucent display-side electrode, prior to completing storage of the first type of electrophoretic particles and the third type of electrophoretic particles on the first back-side electrode.

4. The display device of claim 1, wherein the voltage control section controls applying a voltage to the first back-side electrode to move the first type of electrophoretic particles remaining on the first back-side electrode, prior to completing storage of the second type of electrophoretic particles on the second back-side electrode.

5. The display device of claim 2, wherein the height of the partition wall is ⅓

to ⅔

a separation distance of the substrates.

6. The display device of claim 1, wherein all electrophoretic particles enclosed between the pair of substrates are charged with the same polarity.