US3897997A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic display device with variable reflectivity
Assignee: Individual
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Filing: 1974-08-06
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Granted: 1975-08-05
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Expires: 1994-08-06
Abstract
Abstract An electrostatic display device is described having electrically controllable reflectivity to ambient light. A fixed electrode having a curvature of constant radius is mounted adjacent to and insulated from a resilient variable sheet electrode. On at least one of the adjacent faces of the fixed and variable electrodes there lies an insulating layer. When a voltage is applied between the two electrodes, the variable electrode wraps over the fixed electrode changing its appearance. The device is suitable for example for use as an element in a standard seven segment numeric display unit. It requires very low levels of operating power, is capable of exhibiting a wide range of reflectivities, colors and an effective viewing angle of greater than 120* and is effectively operated in high ambient light environments.
Inventors
- 👤 Charles G Kalt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:59
CPC Classifications
G; G09; G09F; G09F9/00; G09F9/30; G09F9/37; G09F9/372
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
222 words
An electrostatic display device having variable light reflectivity comprising: a. one fixed electrode at least a portion of which has a curved surface of constant radius; b. a film of insulative material being deposited over said curved surface of said fixed electrode, said insulated fixed electrode being opaque to the transmission of light; c. a base to which said fixed electrode is mounted; d. one variable electrode being a sheet of resilient material and having at least one electrically conductive surface, said variable electrode being mounted to said base and standing adjacent to said fixed electrode with the plane of said variable electrode being parallel to the axis of said curved surface, said at least one conductive surface of said variable electrode facing said fixed electrode; and e. a connective means for connecting a voltage between said fixed electrode and said at least one conductive surfacE of said variable electrode, said insulated curved surface of said fixed electrode and the opposite surface from said at least one surface of said variable electrode having distinctly different light reflective characteristics, such that when a voltage is applied between said variable and said fixed electrode said variable electrode is electrostatically pulled and held coadunately over said curved surface and in the presence of ambient light a distinctive change occurs in the appearance of said device.
Claim 2
Dependent Claim
222 words
An electrostatic display device having variable light reflectivity comprising: a. one fixed electrode at least a portion of which has a curved surface of constant radius; b. a film of insulative material being deposited over said curved surface of said fixed electrode, said insulated fixed electrode being opaque to the transmission of light; c. a base to which said fixed electrode is mounted; d. one variable electrode being a sheet of resilient material and having at least one electrically conductive surface, said variable electrode being mounted to said base and standing adjacent to said fixed electrode with the plane of said variable electrode being parallel to the axis of said curved surface, said at least one conductive surface of said variable electrode facing said fixed electrode; and e. a connective means for connecting a voltage between said fixed electrode and said at least one conductive surfacE of said variable electrode, said insulated curved surface of said fixed electrode and the opposite surface from said at least one surface of said variable electrode having distinctly different light reflective characteristics, such that when a voltage is applied between said variable and said fixed electrode said variable electrode is electrostatically pulled and held coadunately over said curved surface and in the presence of ambient light a distinctive change occurs in the appearance of said device.
Claim 3
Dependent Claim
29 words
The display device of claim 1 wherein at least one of said facing electrode surfaces has depressions formed therein for the purpose of reducing pneumatic sticking between said electrodes.
Claim 4
Dependent Claim
30 words
The display device of claim 1 wherein said sheet of resilient material is a resilient polymer resin and said at least one conductive surface is comprised of a metal film.
Claim 5
Dependent Claim
76 words
The display device of claim 3 additionally comprising at least another variable electrode being spaced from said fixed electrode and mounted in said base parallel to said one variable electrode, said one and another variable electrodes having a symmetrical relationship with respect to said one fixed electrode, said at least another variable electrode having another metal film on an inside face thereof, and another connective means for making independent electrical connection to said another variable electrode.
Claim 6
Dependent Claim
21 words
The display device of claim 4 wherein a shim is mounted in each said space between said fixed and variable electrodes.
Claim 7
Dependent Claim
77 words
The display device of claim 1 wherein the location of mounting said variable electrode to said base is spaced from the axis of said surface of constant curvature of said fixed electrode by at least the distance of 1.2 times said radius of said curved surface for the purpose of removing the region of said variable electrodes that may be wrinkled near said mounting from the first point of active contact between said fixed and variable electrodes.
Claim 8
Dependent Claim
46 words
The display device of claim 1 additionally comprising a stationary shielding electrode having a plate shaped portion that is mounted in said base essentially parallel to and spaced from said variable electrode, said opposite surface of said variable electrode being adjacent to said stationary shielding electrode.
Claim 9
Dependent Claim
26 words
The display device of claim 1 wherein the ratio of the dielectric constant to the thickness of said insulative film is greater than 8,000 inverse inches.
Claim 10
Dependent Claim
74 words
The display device of claim 1 additionally comprising another fixed electrode at least a portion of which has a curved surface of said constant radius, and another film of insulative material being deposited over said curved surface of said another fixed electrode, said another insulated fixed electrode being opaque to the transmission of light, said one and said another fixed electrode being symmetrically mounted and disposed on said base relative to said variable electrode.
Claim 11
Dependent Claim
56 words
The display device of claim 1 additionally comprising at least another variable electrode having at least one electrically conductive surface and being mounted to said base and standing in said plane of said one electrode, said at least one conductive surface facing said fixed electrode, said variable electrodes being spaced in said plane from each other.
Claim 12
Dependent Claim
129 words
The display device of claim 1 additionally comprising at least another fixed electrode and at least another variable electrode, said another fixed and variable electrodes having the same features as and bearing the same mutual physical and work-relationships as said one fixed and variable electrodes, said one and said at least another electrodes sharing and being mounted to said base, the radius of curvature of said at least another fixed electrode defining an axis thereof, said axes of said fixed electrodes lying in one plane, said variable electrodes being mounted essentially perpendicular to said plane and being alternately disposed on said plane and being alternately disposed on said base relative to said fixEd electrodes for the purpose of forming an array of two or more individually controllable display devices.
Claim 13
Dependent Claim
33 words
The display device of claim 1 wherein said insulative material is tantalum oxide and wherein the color of said insulated fixed electrode is determined by the spectral interference characteristics of said tantalum oxide.
Claim 14
Dependent Claim
206 words
An electrostatic display device having variable light reflectivity comprising: a. one fixed electrode at least a portion of which has a curved surface of constant radius, said fixed electrode being opaque to light; b. a base to which said fixed electrode is mounted; c. one variable electrode being a resilient laminar sheet comprised of at least one layer of electrically conducting material and at least one layer of electrically insulating material, said variable electrode being mounted to said base and standing adjacent to said fixed electrode with the plane of said variable electrode being parallel to the axis of said curved surface, said at least one insulative layer facing said fixed electrode; and d. a conductive means for connecting a voltage between said fixed electrode and said at least one conductive layer, the opposite surface of said variable electrode from said conductive layer having distinctly different light reflective characteristics than said curved surface of said fixed electrode, such that when a voltage is applied between said variable electrode and said conductive layer of said fixed electrode said variable electrode is electrostatically pulled and held coadunately over said curved surface and in the presence of ambient light a distinctive change occurs in the appearance of said device.
Claim 15
Dependent Claim
206 words
An electrostatic display device having variable light reflectivity comprising: a. one fixed electrode at least a portion of which has a curved surface of constant radius, said fixed electrode being opaque to light; b. a base to which said fixed electrode is mounted; c. one variable electrode being a resilient laminar sheet comprised of at least one layer of electrically conducting material and at least one layer of electrically insulating material, said variable electrode being mounted to said base and standing adjacent to said fixed electrode with the plane of said variable electrode being parallel to the axis of said curved surface, said at least one insulative layer facing said fixed electrode; and d. a conductive means for connecting a voltage between said fixed electrode and said at least one conductive layer, the opposite surface of said variable electrode from said conductive layer having distinctly different light reflective characteristics than said curved surface of said fixed electrode, such that when a voltage is applied between said variable electrode and said conductive layer of said fixed electrode said variable electrode is electrostatically pulled and held coadunately over said curved surface and in the presence of ambient light a distinctive change occurs in the appearance of said device.
Claim 16
Dependent Claim
29 words
The display device of claim 13 wherein at least one of said facing electrode surfaces has depressions formed therein for the purpose of reducing pneumatic sticking between said electrodes.
Claim 17
Dependent Claim
25 words
The display device of claim 13 wherein said laminar variable electrode is comprised of a resilient polymer resin sheet having been metallized on one side.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |