Display device

• US 6,025,896 A
• Filed: 10/06/1998
• Issued: 02/15/2000
• Est. Priority Date: 10/09/1997
• Status: Expired due to Term

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Hattori, Yasuhiro, Ikami, Jun
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NGUYEN, DUNG T
• Application Number:
  US09/166,925
• Time in Patent Office: 497 Days
• Field of Search: 349/86, 349/88, 349/89, 349/90, 349/92, 349/165, 349/183
• US Class Current: 349/86
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16757 Microcapsules
• CPC Class Codes: G02F 1/1681 having two or more microcells partitioned by walls, e.g. of microcup type

Abstract

The display device, which is devoid of display defects and capable of being drived with low power, comprises a large number of microcapsules 10 in which disperse systems of charged particles 2 in a liquid dispersion medium 4 are encapsulated, and a pair of transparent electrodes 14 faced to each other disposed such that these microcapsules 10 is sandwiched therebetween. The diameters of the charged particles 2 are about 1/1000 to about 1/5 of the particle diameters of the microcapsules 10, and the charged particles 2 are dispersed such that the dispersion degree of the particle diamter distribution, expressed as volume-average particle diameter/number-average particle diameter, ranges from 1 to about 2, where the volume-average particle diameter indicates an average particle diameter derived from a volume-based particle diameter distribution and the number-average particle diameter indicates an average particle diameter derived from a number-based particle diameter distribution.

Claims

1. A display device, which comprises a large number of microcapsules in which disperse systems of charged particles in a dispersion medium are encapsulated, and a pair of electrodes faced to each other disposed such that the microcapsules are sandwiched therebetween, and in which optical reflection characteristics are varied and the desired display operation is executed by varying the dispersion state of said charged particles under the action of controlling voltage;

wherein

the diameters of said charged particles are about 1/1000 to about 1/5 of the particle diameters of said microcapsules; and

said charged particles are dispersed such that the dispersion degree of the particle diameter distribution, expressed as volume-average particle diameter/number-average particle diameter, ranges from 1 to about 2;

the volume-average particle diameter indicating an average particle diameter derived from a volume-based particle diameter distribution and the number-average particle diameter indicating an average particle diameter derived from a number-based particle diameter distribution.

2. A display device according to claim 1, wherein the particle diameters of said microcapsules are about 5 μ

m to about 200 μ

m.

3. A display device according to claim 1, wherein the volume of each of said charged particles constitutes from about 1.5% to about 25% of the volume of the corresponding microcapsule;

and the total volume of all the charged particles in said microcapsules constitutes from about 1.5% to about 50% of the volume of said microcapsules.

4. A display device according to claim 1, wherein said microcapsules are supported on a flexible medium.

5. A display device according to claim 4, wherein said microcapsules are not movable with respect to a pair of the electrodes.

6. A display device according to claim 4, wherein said flexible medium fixing the microcapsules is movable with respect to a pair of the electrodes.

7. A display device according to claim 1, wherein said charged particles are comprised of at least one type of polymerization particles.