Gyricon media using amorphous silicon thin film transistor active matrix arrays and a refresh method for the same

• US 20050253802A1
• Filed: 05/14/2004
• Published: 11/17/2005
• Est. Priority Date: 05/14/2004
• Status: Abandoned Application

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Wright, Charles A.
• Application Number:
  US10/845,712
• Publication Number:
  US 20050253802A1
• Time in Patent Office: Days
• US Class Current: 345/107
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 3/3453 based on rotating particles or microelements

Abstract

A gyricon medium comprising amorphous silicon thin film transistor active matrix arrays and a method of refreshing a gyricon active matrix display. The method involves the use of field effect instead of current flow in altering the orientation of rotary balls in a gyricon medium, thereby emulating the high brightness and contrast characteristics of paper in a low-power display.

Claims

1. A gyricon medium configured to operate with active matrix arrays, comprising:

a gyricon medium having two opposing surfaces;

an electrode forming a first plate disposed over one of the two opposing surfaces; and

a matrix of thin film transistors (TFTs) disposed over the other opposing surface;

wherein conductors of the matrix of TFTs form a second plate sequestering the gyricon medium betwixt the two plates.

2. The gyricon medium according to claim 1, wherein the gyricon medium comprises electrically switchable rotary balls.

3. The gyricon medium according to claim 2, wherein each of the rotary balls comprises at least two portions, each portion having an associated optical characteristic that signal change of state of the rotating ball.

4. The gyricon medium according to claim 2, wherein each of the rotary balls has anisotropy for providing and electrical dipole moment that responds to an electric field by rotating the ball.

5. The gyricon medium according to claim 1, wherein the first plate comprises indium oxide, tin oxide or indium-tin oxide (ITO).

6. The gyricon medium according to claim 1, wherein a voltage potential applied across the medium using the first and second plates causes the gyricon medium to change state.

7. An electro-optical composite comprising:

a material having a plurality of components;

at least one component capable of being set into motion by electromotive forces, the component comprising at least two portions, each portion having an associated optical characteristics;

an electrode disposed over a surface of the material, the material having two opposing surfaces; and

a matrix of thin film transistors disposed over the other opposing surface of the material.

8. The electro-optical composite according to claim 7, wherein the material comprises a gyricon medium.

9. The electro-optical composite according to claim 7, wherein the component capable of being set into motion comprises a rotary ball having an orientation in a cavity filled with liquid.

10. The electro-optical composite according to claim 7, wherein at least one of the two portions has a reflective optical characteristic and the other has an absorptive optical characteristic.

11. The electro-optical composite according to claim 7, wherein the electrode comprises indium oxide, tin oxide or indium-tin oxide (ITO).

12. The electro-optical composite according to claim 7, wherein the thin film transistors controls the orientation of the ball in the cavity.

13. A gyricon active matrix assembly comprising:

a transmissive electro-optical device including a plurality of gyricon components; and

a plurality of field effect transistors arranged to provide data signals to the plurality of gyricon components.

14. The gyricon active matrix assembly according to claim 13, wherein the gyricon components comprise a transparent medium.

15. The gyricon active matrix assembly according to claim 13, wherein the gyricon components comprise at least one electrically switchable rotary ball.

16. The gyricon active matrix assembly according to claim 15, wherein the rotary ball comprises at least two portions, each portion having an associated optical characteristic that signal change of state of the rotating ball.

17. The gyricon active matrix assembly according to claim 13, wherein the rotary ball has anisotropy for providing and electrical dipole moment that responds to an electric field.

18. The gyricon active matrix assembly according to claim 13, wherein the field effect transistors provide the electrical field for rotary ball to respond.

19. A method of using amorphous silicon thin film transistors in operating a gyricon active matrix display, comprising the steps of:

providing a gyricon active matrix display having an array of field effect transistors (FETs);

initializing the matrix display;

performing alternating refresh sequence; and

impressing voltage to all conductors of the array of FETs simultaneously.

20. The method of operating a gyricon active matrix display according to claim 19, wherein the gyricon comprises a transparent medium having electrically switchable rotatable balls that orient themselves in accordance with an electric field that is imposed on them by an array of field effect transistors.

21. The method of operating a gyricon active matrix display according to claim 19, wherein the initializing the matrix display comprises applying a voltage across the display to provide an all white reflection facing away from the FETs.