Nonemissive displays and piezoelectric power supplies therefor

• US 6,130,773 A
• Filed: 11/10/1998
• Issued: 10/10/2000
• Est. Priority Date: 10/25/1996
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Jacobson, Joseph M., Comiskey, Barrett
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Lester, Evelyn A.
• Application Number:
  US09/189,254
• Time in Patent Office: 700 Days
• Field of Search: 359/296, 345/107, 40/124.01, 40/124.02, 40/124.09, 40/124.11, 40/124.12, 36/136, 36/137
• US Class Current: 359/296
• CPC Class Codes: B41J 3/4076 printing on rewritable, bistable "electronic paper" by a focused electric or magnetic field
• CPC Class Codes: G01C 22/006 Pedometers
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16757 Microcapsules
• CPC Class Codes: G02F 1/1685 Operation of cells; Circuit arrangements affecting the entire cell
• CPC Class Codes: G08B 5/226 with alphanumeric or graphic display means

Abstract

An electrophoretic display has a substantially two-dimensional arrangement of microcapsules each having therein an electrophoretic composition of a dielectric fluid and a suspension of particles that visually contrast with the dielectric liquid and also exhibit surface charges; a pair of electrodes, at least one of which is visually transparent, disposed on and covering opposite sides of the microcapsule arrangement; and a power source for creating a potential difference between the two electrodes, the potential difference causing the particles to migrate toward one of the electrodes. The display may be powered by one or more piezoelectric elements, which are also suitable for powering other types of nonemissive displays.

Claims

1. A nonemissive display system comprising:

a. a paper substrate;

b. at least one electrophoretic display element attached to a surface of the paper substrate for display thereon, the electrophoretic display element comprising discrete microcapsule containers each containing a dielectric fluid and a suspension therein of particles exhibiting surface charges, the fluid and the particles contrasting visually;

c. a power source for creating a potential difference across the at least one display element; and

d. means for selectably actuating the power source.

2. The display system of claim 1 wherein the power source is a piezoelectric element.

3. A nonemissive display system comprising:

a. a paper substrate;

b. at least one electrophoretic display element associated with the paper substrate, the electrophoretic display element comprising discrete microcapsule containers each containing a dielectric fluid and a suspension therein of particles exhibiting surface charges, the fluid and the particles contrasting visually;

c. a power source for creating a potential difference across the at least one display element, the power source comprising a piezoelectric element; and

d. means for selectable actuating the power source,

wherein folding of the paper substrate deforms the piezoelectric element, thereby creating the potential difference.