Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1999-06-21
2001-04-24
Liang, Regina (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C359S296000
Reexamination Certificate
active
06222519
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to visual displays comprising rotating hollow beads strung on strings and utilizing optical and electromagnetic anisotropy.
Electrophoresis and triboelectricity are both surface phenomena whereby electric charge is generated on a surface. The combination of electrophoreses and triboelectricity on the same surface enhances the generation and retention of charge over either acting alone. Magnetic anisotropy is established by means of a material that exhibits magnetic activity. For purposes of this invention the term ‘electromagnetic activity’ will be used to describe activity attributable to either electric activity or magnetic activity acting alone or in combination. Visual anisotropy is achieved by the utilization of colored materials. Display elements are formed as hollow beads on a string or fiber and the beads may be cylindrical, spherical, or of some other shape. The beads are hollow in the sense that they include a central hole through the bead near an axis. The string serves to confine the beads during fabrication and remains an integral part of the resultant display device whereby fabrication is facilitated and mechanical robustness is achieved in the final product.
Triboelectricity is the production of electric charge by friction or contact between dissimilar materials. Friction or relative motion between the materials develops electric charge. Triboelectricity has been and is a key process in the xerographic industry. Toner articles dispersed through an array of capillaries receive electric charge by contact and/or friction as they transit the capillaries. Particles or materials that have acquired surface charge by triboelectricity are capable of being moved, positioned and oriented by an electric field. A novel application of this feature is the utilization of triboelectric materials that develop positive charge along with triboelectric materials that develop negative charge to create bipolar and/or multi-polar particles. The resultant particle is capable of orientation in an electric field. This feature has been described in my U.S. Pat. No. 5,940,054 “TRIBOELECTRIC ELECTRET”, which is incorporated herein by reference.
Electrophoreses is an electrochemical process where by an electric charge is developed at a solid-liquid interface as a result of an electrokinetic potential, the zeta-potential. As a result of the induced surface charge a particle will exhibit mobility under the influence of an electrical field. This effect is the basis of liquid xerographic applications. There is experimental evidence that the charge on suspended particles deteriorate with time. In particular, negatively charged particles may lose their charge in a few hours or days.
An inventive application described herein utilizes particles having surface areas that are comprised of materials that exhibit both triboelectric and electrophoretic activity. Electrophoreses generates charge even in the absence of friction or relative motion. Triboelectric effects on the other hand generate charge by friction independent of the electrokinetic potential. In the case of electrophoreses by itself, any ions within the liquid medium will migrate to charged areas on the particles, degrading the charge. These ions can be removed and the charge replenished by triboelectricity. By the combined action of these two effects charge is developed and retained under a wider range of condition than available with either by itself.
Electrophoretic charge anisotropy is the basis for a number of display approaches that utilize bipolar particles. These included, among others, those described in U.S. Pat. No. 4,126,854 (1978), U.S. Pat. No. 4,261,653 (1981), and U.S. Pat. No. 5,751,268 (1998). These prior art systems in general utilize anisotropic microspheres in a fluid filled cavity in an elastomer that is thick relative to the cavities. Electrodes are not integral with the cavity. Drive voltages must be applied external to the elastomer. Because of the elastomer thickness drive voltages are, typically, several tens of volts. With electrophoreses alone a very high resistivity liquid is mandated, and the high resistivity must be maintained over the lifetime of the apparatus. There is no means to replenish charge lost due to ion migration within the liquid.
In the present invention a preferred approach utilizes hollow micro cylindrical elements as beads on a string and in a plurality of cavities wherein drive electrodes are included. These micro cylinders are produced as “beads-on-a-string” by drawing a glass fiber from a preform that is comprised of a number of glass strands and by subsequent processing. A selection of glasses are fused into a preform comprising a plurality of colored glasses fused into a tube around a soluble glass tube which is in turn fused to a relative inert glass core. The preform is heated and pulled into a fiber using well-known techniques. A fiber results which posses essentially the same cross section of glasses as the preform. State of the art methods allow the pulling very long fibers of clad glass having the extreme uniformity and the very small diameters needed to support single mode propagation of laser light.
Colored glass is the preferred material for the outer surface of the fiber. However, optionally, the outer surface of a fiber can be coated with dye dispersed within a suitable polymer to achieve a desired color or plurality of colors.
An optional glass component of the preform, and hence resultant fiber, comprises a glass having magnetic capabilities, for instance iron oxide interspersed in silicon dioxide. Following pulling into a fiber a magnetic polarization is established in the magnetizable glass by an external magnetic field. Exploiting the natural hysteresis of the iron oxide the induced magnetic polarization remains within the glass after the external field is removed.
Subsequent to the pulling the fiber, polymers having a combination of electrophoretic and triboelectric activity are applied to selected regions of the fiber surface. These polymers are selected to exhibit electric activity whereby the triboelectric and electrophoretic activities reinforce each other.
The fiber is next processed to achieve a string of hollow beads-on-a-string wherein each bead comprises a display element bead whereby one picture element is displayed. The multi colored outer region is cut into bead defining segments utilizing state-of-are-art methods. A photo-resist is applied to the fiber, optical exposure of a plurality of rings along the fiber defines the cylindrical elements, and the soluble resist is removed. The resulting rings of unprotected glass are then etched sufficiently deep to cut through the outer multi colored surface glass, but not deep enough to reach entirely through the to the central hard glass core. The uncut portions of the fiber maintain fiber integrity for subsequent processing. When, in a later step the soluble glass is finally dissolved the inert central core remains as string the plurality of multicolor bead segments are cut free to become orientable hollow beads-on-a-string. Each bead is a hollow cylinder comprised of segments of colored glass possessing triboelectric/electrophoretic coatings indexed to the glass colors. Each bead includes both optical and electric isotropy and will become a display element in the inventive display that is the subject of the present invention. The thread upon which the beads are strung is comprised of the uncut fiber core and serves to confine the beads throughout subsequent processing and remain with the beads in the final display device. Manipulation of the very large numbers of elements, which will comprise the display, is greatly facilitated by confining the beads to a string and by further confining the strings of beads to a loom.
Optionally, a smaller bead can be formed coaxially with a larger bead of the same length and occupying the same location on the string. The two coaxial beads at a common display element location allow a more expansive color palette. The two beads of th
LandOfFree
Roller optical gate display device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Roller optical gate display device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Roller optical gate display device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2507246