Fabrication of a twisting ball display having two or more different kinds of balls

• US 5,982,346 A
• Filed: 12/15/1995
• Issued: 11/09/1999
• Est. Priority Date: 12/15/1995
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Mackinlay, Jock D., Sheridon, Nicholas K., Stone, Maureen C.
• Primary Examiner(s): Chow, Dennis-Doon
• Application Number:
  US08/572,777
• Time in Patent Office: 1,425 Days
• Field of Search: 345/85, 345/86, 345/84, 345/111, 345/55, 345/150, 345/151, 345/107, 345/108, 359/296, 349/80
• 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

Abstract

A method of making a substrate in which sets of optically anisotropic spheroidal balls are disposed, as for use in an electrical twisting ball display. First and second sets of spheroidal balls, are deposited on a receiving surface composed of an elastomer substrate material in an adhesive state, the spheroidal balls thus deposited adhering to the receiving surface. Balls of the first and second sets are physically distinguishable from one another. Balls of the first set can be deposited in a first arrangement, and balls of the second set, in a second arrangement. Each ball of each set has an optical anisotropy and an anisotropy for providing an electrical dipole moment, the electrical dipole moment rendering the ball electrically responsive such that when the ball is rotatably disposed in an electric field while the electrical dipole moment of the ball is provided, the ball tends to rotate to an orientation in which the electrical dipole moment aligns with the field. With the balls thus deposited, additional, liquid elastomer material is poured over the balls adhering to the receiving surface, thereby covering the balls and forming an uncured substrate material in which the balls are disposed. This uncured substrate material is cured to form a substrate in which balls of the first and second sets are disposed. A plasticizer fluid can be applied to the substrate thus formed, thereby expanding the substrate so as to render the balls disposed in the substrate rotatable within the substrate.

Claims

1. A material comprising:

a substrate; and

first and second pluralities of spheroidal balls disposed in the substrate,

each ball of the first plurality having a first collection of physical characteristics, including at least one physical characteristic that renders at least a portion of each ball transparent,

each ball of the second plurality have a second collection of physical characteristics, spheroidal balls of the second plurality thus being physically distinguishable from spheroidal balls of the first plurality, and

each ball of each plurality having an optical anisotropy and an anisotropy for providing an electrical dipole moment, the electrical dipole moment rendering the ball electrically responsive such that when the ball is rotatably disposed in an electric field while the electrical dipole moment of the ball is provided, the ball tends to rotate to an orientation in which the electrical dipole moment aligns with the field.

2. The material of claim 1 wherein each of the physical characteristics of each of the first and second collections is selected from the group consisting of:

an electrical characteristic, a mechanical characteristic, a structural characteristic, a material characteristic, an optical modulation characteristic,

dipole moment, monopole moment, dipole moment in the presence of a dielectric fluid, zeta potential distribution in the presence of a dielectric fluid,

mass, moment of inertia, size, mean radius, shape, deviation from spherical shape, coefficient of friction, surface roughness,

size and shape of a component region within the ball, disposition of any component regions within the ball relative to one another,

any material used in the manufacture of any component region within the ball, any material coating a surface of the ball,

color, polarization, birefringence, phase retardation, light scattering, reflection, and an optical modulation characteristic of any component region within the ball.

3. The material of claim 1 wherein:

the substrate has a surface and includes first and second sets of image elements disposed in the substrate, each set comprising a plurality of image elements, the first and second sets being disjunct from one another such that no image element of the first set belongs to the second set and no image element of the second set belongs to the first set,

each image element having an observable area, the observable area of each image element being observable by an observer situated favorably to observe the substrate surface and not overlapping with the observable area of any other image element, the observable areas of the first and second sets being arranged in a geometrical pattern observable by the observer;

each ball of the first plurality of spheroidal balls is disposed in an image element of the first set; and

each ball of the second plurality of spheroidal balls is disposed in an image element of the second set.

4. The material of claim 1 and further comprising:

a third plurality of spheroidal balls disposed in the substrate,

each ball of the third plurality having a third collection of physical characteristics, spheroidal balls of the third plurality thus being physically distinguishable from spheroidal balls of the first and second pluralities,

each ball of the third plurality having an optical anisotropy and an anisotropy for providing an electrical dipole moment, the electrical dipole moment rendering the ball electrically responsive such that when the ball is rotatably disposed in an electric field while the electrical dipole moment of the ball is provided, the ball tends to rotate to an orientation in which the electrical dipole moment aligns with the field.

5. An apparatus comprising:

a piece of the material recited in claim 1, wherein at least one spheroidal ball is rotatably disposed in the substrate of the piece of material; and

means for producing an electric field to facilitate a rotation of at least one ball rotatably disposed in the substrate of the piece of material.

6. The apparatus of claim 5 wherein the field-producing means comprises:

means for producing an electric field so as to facilitate a rotation of at least one ball of the second plurality without facilitating a rotation of any ball of the first plurality.

7. A material comprising:

a substrate having a first surface and a plurality of underlying regions, including at least a first region and a second region; and

a plurality of spheroidal balls selectively and rotatably arranged within each of the plurality of regions, each of the spheroidal balls having a plurality of segments that cause the spheroidal ball to be electrically anisotropic such that the spheroidal ball selectively rotates to a specific orientation with respect to the first surface in response to at least one externally generated electrical field,

wherein the spheroidal balls within the first region are substantially identical, the spheroidal balls within the second region are substantially identical, at least one of the segments in each of the spheroidal balls within the first region provides a different optical modulation characteristic than at least one of the segments in each of the spheroidal balls in the second region, and at least one of the segments in at least one of the spherodial balls in the first region is substantially optically transparent.