Writing system including paper-like digitally addressed media and addressing device therefor

• US 5,389,945 A
• Filed: 11/19/1993
• Issued: 02/14/1995
• Est. Priority Date: 11/08/1989
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Sheridon, Nicholas K.
• Primary Examiner(s): Oberley, Alvin E.
• Assistant Examiner(s): Saras, Steven J.
• Application Number:
  US08/156,527
• Time in Patent Office: 452 Days
• Field of Search: 365/127, 345/48, 345/84, 345/85, 345/86, 345/87, 345/108-111, 358/473
• US Class Current: 345/85
• CPC Class Codes: G02B 26/026 based on the rotation of particles under the influence of an external field, e.g. gyricons, twisting ball displays based on orientable dipolar particles G02F1/172; based on electrophoresis G02F1/167
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: H01H 2219/0023 Images formed with electrophoretic technology, e.g. by charged pigment particles rearranged by applied electric field, e.g. electronic paper or e-paper, active ink

Abstract

An addressable display system including a paper-like sheet comprising a light transparent host layer loaded with a plurality of repositionable elements, the elements are movable from a first orientation in which they will present a first visual appearance, to a second orientation in which they will present a second visual appearance, and independent external addressing means relatively movable with respect to the display sheet for affecting the orientation of the repositionable elements.

Claims

1. A writing system including a reusable planar writing sheet for use with an addressing device which is capable of imposing human perceivable information on said writing sheet, said writing sheet and said addressing device being normally independent and remote from one another when said writing sheet is not being addressed, and wherein said writing sheet and said addressing device are brought into proximity with and are moved relative to one another for imposing information on said writing sheet,

said writing sheet has a surface upon which information can be written and erased, exhibits ambient light valve behavior, has the ability to retain imposed information in the absence of an external retaining ibrce, and has the capability of being rolled into tubular form about any axis lying in the plane of said sheet, said writing sheet further comprises a light transparent host layer, a plurality of reorientable substantially spherical balls having at least two dissimilar surface portions of contrasting colors and different surface charges, each of said balls being contained, and free to rotate, within a cavity in said host layer, said reorientable balls being movable from a fixed and stable first orientation, in which they will present a first visual appearance, to a fixed and stable second orientation, in which they will present a second visual appearance,

said addressing device includes an array of electrically chargeable electrodes for dislodging said balls from one fixed and stable orientation and initiating rotation thereof, and a holding electrode for completing rotation of said balls to the other fixed and stable orientation.

2. The writing system as defined in claim 1 wherein each of said electrically chargeable electrodes in said array is switchably connected to a first potential source, the magnitude of said first potential being sufficient to dislodge said balls from one fixed and stable orientation and to initiate rotation thereof, and said holding electrode is connected to a second potential source, the magnitude of said second potential being insufficient to dislodge said balls from a fixed and stable orientation, but being sufficient to cause said dislodged balls to rotate to completion and to lodge in said other fixed and stable orientation.

3. The writing system as defined in claim 1 wherein said holding electrode is coextensive with said array of electrically chargeable electrodes and is positioned to trail said array as said writing sheet and said addressing device are moved relative to one another.

4. The writing system as defined in claim 3 wherein said holding electrode is dimensioned relative to said array of electrically chargeable electrodes so that said balls will be under the influence of said holding electrode for a longer period of time than they are under the influence of said chargeable electrodes.

5. The writing system as defined in claim 3 wherein said holding electrode is separated from said array of electrically chargeable electrodes by a dielectric member.

6. The writing system as defined in claim 2 wherein the sign of said first potential source and said second potential source is the same.

7. The writing system as defined in claim 1 wherein said writing sheet includes registration features thereon and said addressing device includes a sensing device capable of identifying said registration features and generating signals in response thereto.

8. The writing system as defined in claim 7 further including a reading device housed together with said addressing device.

9. The writing system as defined in claim 8 wherein said reading device comprises an optical scanning array substantially coextensive with said array of electrically chargeable electrodes.

10. The writing system as defined in claim 7 further including a reading device being normally independent and remote from said writing sheet and said addressing device.

11. The writing system as defined in claim 10 wherein said reading device comprises an optical scanning array substantially coextensive with said array of electrically chargeable electrodes.