US4187160A
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Method and apparatus for operating an electrophoretic indicating element
Assignee: BBC Brown Boveri AG Switzerland
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Filing: 1978-07-18
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Granted: 1980-02-05
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Expires: 1998-07-18
Abstract
Abstract A method and apparatus for operating an electrophoretic indicating element driven by a drive signal, wherein the drive signal is modulated by an alternating voltage signal superimposed on the drive signal and having a frequency sufficiently high to prevent observation thereof. The modulating signal can have either a sinusoidal, triangular, or rectangular wave shape, or can be a succession of individual wave trains wherein the duration of each wave train is selected in accordance with the composition of the electrophoretic switching element.
Inventors
- 👤 Andreas Zimmermann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:15
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/3433; G09G3/344; G02; G02F; G02F1/00; G02F1/01; G02F1/165; G02F1/166; G02F1/167; G02F1/1685; G09G2310/00; G09G2310/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
40 words
A method of operating an electrophoretic indicating element having a suspension containing a pigment which exhibits a switching time, in which said element is driven by a drive signal, comprising: superimposing an alternating voltage signal directly on said drive signal.
Claim 2
Independent Claim
40 words
A method of operating an electrophoretic indicating element having a suspension containing a pigment which exhibits a switching time, in which said element is driven by a drive signal, comprising: superimposing an alternating voltage signal directly on said drive signal.
Claim 3
Dependent Claim
38 words
A method as claimed in claim 1, in which the frequency of the superimposed alternating-voltage signal is sufficiently high such that switching operations caused in the indicating element by this signal can not be perceived by an observer.
Claim 4
Dependent Claim
24 words
A method as claimed in claim 2, in which the frequency of the superimposed alternating-voltage signal is greater than or equal to 20 Hz.
Claim 5
Dependent Claim
14 words
A method as claimed in claim 1, wherein the superimposed alternating-voltage signal is sinusoidal.
Claim 6
Dependent Claim
14 words
A method as claimed in claim 1, wherein the superimposed alternating-voltage signal is triangular.
Claim 7
Dependent Claim
14 words
A method as claimed in claim 1, wherein the superimposed alternating-voltage signal is rectangular.
Claim 8
Dependent Claim
50 words
A method as claimed in claim 1, wherein the superimposed alternating-voltage signal comprises a succession of individual wave trains, the duration of each wave train being at least equal to the switching time of the pigment, and the beginning of each wave train coinciding with an alteration in switching state.
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) | 1983-02-04 | 1983-08-06 | 1984-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-04 | 1987-08-06 | 1988-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-04 | 1991-08-06 | 1992-02-05 | $7700.00 | Window Closed / Lapsed |