Gyricon displays utilizing rotating elements and magnetic latching

• US 6,147,791 A
• Filed: 11/25/1998
• Issued: 11/14/2000
• Est. Priority Date: 11/25/1998
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Sheridon, Nicholas K.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Lester, Evelyn A.
• Application Number:
  US09/199,403
• Time in Patent Office: 720 Days
• Field of Search: 359/296, 345/10, 345/107
• US Class Current: 359/296
• 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: G09F 9/375 the position of the elements being controlled by the application of a magnetic field

Abstract

A sheet material for use in a gyricon display in which a rotatable element, which has a portion which is capable of being permanently magnetized may be oriented to experience an attractive force between itself and a soft magnetic material pad. The attractive force between the element and the pad serve to latch the element in place and prevent unwanted display changes from taking place. The element may be constructed to be either cylindrically or spherically shaped. The element and the soft magnetic material pads may be arranged to provide multiple latching states as desired.

Claims

1. A material comprising:

a) a substrate having two opposed surfaces,

b) at least one element, which is capable of being made rotatable by a non-destructive operation, having a diameter and a circumference, disposed in the substrate, said element comprising at least two portions, each portion having an associated optical modulation characteristic, the optical modulation characteristic of at least one portion being different from the optical modulation characteristic of at least one other portion, wherein at least one portion is capable of being permanently magnetized and at least one portion is not capable of being permanently magnetized, and wherein the element has an anisotropy for providing an electrical dipole moment, the electrical dipole moment rendering the element electrically responsive such that when the rotating element is rotatably disposed in an electric field while the electrical dipole moment of the element is provided, the element tends to rotate to an orientation in which the electrical dipole moment aligns with the field, and

c) at least one soft magnetic material pad disposed within said substrate associated with the at least one element, spaced from the associated element and so constructed and arranged such that when the at least one portion of the element which is capable of being permanently magnetized is magnetized and the element is oriented such that the at least one magnetized portion of the element is the portion of the element nearest the soft magnetic material pad a magnetic attractive force will exist between the soft magnetic material pad and the at least one magnetized portion.

2. The material of claim 1 wherein said at least one element has been made rotatable by a non-destructive operation.

3. The material of claim 1 wherein said at least one element is substantially spherical.

4. The material of claim 1 wherein said at least one element is substantially cylindrical.

5. The material of claim 1 wherein the soft magnetic material pad has a length which is no smaller than approximately one-fourth of the diameter of said at least one element.

6. The material of claim 1 wherein the soft magnetic material pad is separated from said at least one element by no more than approximately the diameter of said at least one element multiplied by a factor of three.

7. The material of claim 1 wherein said at least one soft magnetic material pad substantially comprises a ring around said at least one associated element.

8. The material of claim 1 wherein two soft magnetic material pads are associated with said at least one element and are spaced apart from each other around the circumference of said element.

9. The material of claim 1 wherein three soft magnetic material pads are associated with said at least one element and are spaced apart from each other around the circumference of said element.

10. The material of claim 1 wherein four soft magnetic material pads are associated with said at least one element and are spaced apart from each other around the circumference of said element.

11. The material of claim 8 wherein the two soft magnetic material pads are arranged to be opposed to each other.

12. The material of claim 1 wherein said at least one element is further constructed and arranged such that each portion comprises a segment and said element is comprised of at least two segments arrayed substantially parallel to one another, wherein each segment is adjacent to at least one other segment and to no more than two other segments, each segment adjacent to exactly one other segment is an exterior segment, and each segment adjacent to exactly two other segments is an interior segment.

13. The material of claim 12 wherein said at least one element further comprises at least three segments.

14. The material of claim 13 wherein the segment of said at least one element which is capable of being permanently magnetized is an interior segment.

15. The material of claim 13 wherein the segment of said at least one element which is capable of being permanently magnetized is an exterior segment.

16. The material of claim 15 wherein the exterior segment capable of being permanently magnetized is a polar end segment.

17. The material of claim 13 wherein said at least one element further comprises two segments capable of being permanently magnetized and at least one segment not capable of being permanently magnetized interposed therebetween.

18. The material of claim 17 wherein at least one of the two segments capable of being permanently magnetized is a polar end segment.

19. The material of claim 18 wherein said at least one element further comprises at least four segments, wherein both of the two segments capable of being permanently magnetized are polar end segments and two segments not capable of being permanently magnetized are interposed between the polar end segments.

20. The material of claim 4 wherein said at least one element further comprises

a) a first portion being a substantially clear cylindrical shape having a circumference, a length and a longitudinal axis,

b) a multi-sided display surface being at least three portions, each portion being a display surface, the display surfaces being arranged in a circumferential direction around the longitudinal axis to form a substantially polyhedral column having at least three vertices and which extends substantially parallel to the longitudinal axis wherein each display surface has an associated optical modulation characteristic, and the polyhedral column is substantially enclosed by the substantially clear cylindrical shape, and

c) at least three magnetic portions, each magnetic portion being capable of being permanently magnetized and being substantially parallel to the longitudinal axis, the at least three magnetic portions being so constructed and arranged such that each vertex substantially contains one of the at least three magnetic portions.

21. The material of claim 20 wherein three soft magnetic material pads are associated with said at least one element and are spaced apart from each other around the circumference of said element.

22. The material of claim 20 wherein the multisided display surface of said at least one element comprises four portions being display surfaces.

23. The material of claim 20 wherein four soft magnetic material pads are associated with said at least one element and are spaced apart from each other around the circumference of said element.

24. The material of claim 1 further comprising an additional soft magnetic material means, so constructed and arranged such that when the at least one portion of the element which is capable of being permanently magnetized is magnetized and the element is oriented such that the at least one magnetized portion of the element is the portion of the element nearest the soft magnetic material pad a magnetic attractive force will exist between the soft magnetic material pad and the at least one magnetized portion.

25. The material of claim 24 wherein the additional soft magnetic material means comprises a substantially uniform layer substantially parallel to one of the surfaces of the substrate.

26. The material of claim 24 wherein the soft magnetic material pad and the additional soft magnetic material means are opposed to each other.

27. The material of claim 15 wherein the soft magnetic material pad and the additional soft magnetic material means are transverse to each other.

28. The material of claim 15 wherein the soft magnetic material pad has a length which is no smaller than approximately one-fourth of the diameter of said at least one element.

29. The material of claim 15 wherein the soft magnetic material pad is separated from said at least one element by no more than approximately the diameter of said at least one element multiplied by a factor of three.

30. A material comprising:

a) a substrate

b) at least one rotatable element disposed in the substrate, said rotatable element having a diameter and a circumference and said element comprising at least two segments arrayed substantially parallel to one another, wherein each segment is adjacent to at least one other segment and to no more than two other segments, each segment adjacent to exactly one other segment is an exterior segment, and each segment adjacent to exactly two other segments is an interior segment, each segment having an associated optical modulation characteristic, the optical modulation characteristic of at least one segment being different from the optical modulation characteristic of at least one other segment, wherein at least one segment is capable of being permanently magnetized and at least one segment is not capable of being permanently magnetized, and wherein the element has an anisotropy for providing an electrical dipole moment, the electrical dipole moment rendering the element electrically responsive such that when the rotating element is rotatably disposed in an electric field while the electrical dipole moment of the element is provided, the element tends to rotate to an orientation in which the electrical dipole moment aligns with the field, and

c) at least one soft magnetic material pad disposed within said substrate and associated with the at least one element, said at least one soft magnetic material pad being spaced from the associated element and so constructed and arranged such that when the at least one portion of the element which is capable of being permanently magnetized is magnetized and the element is oriented such that the at least one magnetized portion of the element is the portion of the element nearest the soft magnetic material pad a magnetic attractive force will exist between the soft magnetic material pad and the at least one magnetized portion.

31. A material comprising:

a) a substrate

b) at least one rotatable element disposed in the substrate, said rotatable element comprising;

i) a substantially clear cylindrical shape having a circumference, a length and a longitudinal axis,

ii) at least three display surfaces, the display surfaces being arranged in a circumferential direction around the longitudinal axis to form a substantially polyhedral column having at least three vertices and which extends substantially parallel to the longitudinal axis wherein each display surface has an associated optical modulation characteristic, and the polyhedral column is substantially enclosed by the substantially clear cylindrical shape, and

iii) at least three magnetic portions, each magnetic portion being capable of being permanently magnetized and being substantially parallel to the longitudinal axis, the at least three magnetic portions being so constructed and arranged such that each vertex substantially contains one of the at least three magnetic portions, wherein the element has an anisotropy for providing an electrical dipole moment, the electrical dipole moment rendering the element electrically responsive such that when the rotating element is rotatably disposed in an electric field while the electrical dipole moment of the element is provided, the element tends to rotate to an orientation in which the electrical dipole moment aligns with the field, and,

c) at least three soft magnetic material pads disposed within said substrate and associated with the at least one element, said at least three soft magnetic material pads being spaced from the associated element and separated from each other around the circumference of the and element, and being so constructed and arranged such that when the at least one portion of the element which is capable of being permanently magnetized is magnetized and the element is oriented such that the at least one magnetized portion of the element is the portion of the element nearest the soft magnetic material pad a magnetic attractive force will exist between the soft magnetic material pad and the at least one magnetized portion.