US4255238A
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US
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Method of control for an electrolytic display cell and especially a cell of the metal halide type and a circuit for the application of said method
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1979-06-13
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Granted: 1981-03-10
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Expires: 1999-06-13
Abstract
Abstract The electrolytic display cell comprises a plurality of electrodes having suitable shapes for character display, a counter-electrode and an electrolyte. A negative voltage is applied to one of the electrodes for writing on said electrode and a positive voltage is applied for erasure. On completion of erasure, the voltage between electrode and counter-electrode has a tendency to rise to a threshold value corresponding to a parasitic reaction. The end of the erasure pulses is determined by the instant at which the electrode-counter-electrode voltage rises to the threshold voltage corresponding to the production of a parasitic reaction.
Inventors
- 👤 Gilles Delapierre
- 👤 Robert Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:26
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/15; G02F1/163
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
128 words
A method of control of an electrolytic display cell in which said cell comprises a plurality of electrodes having shapes suited to the display of characters, a counter-electrode and an electrolyte, in which a negative voltage is applied to one of the electrodes in order to initiate writing on said electrode and a positive voltage pulse is applied to said electrode in order to initiate erasure and in which the voltage between said electrode and said counter-electrode on completion of erasure has a tendency to rise to a threshold value corresponding to the production of a parasitic reaction, wherein the end of the erasure pulse is determined by the instant at which the electrode--counter-electrode voltage rises to the threshold voltage corresponding to the production of a parasitic reaction.
Claim 2
Independent Claim
128 words
A method of control of an electrolytic display cell in which said cell comprises a plurality of electrodes having shapes suited to the display of characters, a counter-electrode and an electrolyte, in which a negative voltage is applied to one of the electrodes in order to initiate writing on said electrode and a positive voltage pulse is applied to said electrode in order to initiate erasure and in which the voltage between said electrode and said counter-electrode on completion of erasure has a tendency to rise to a threshold value corresponding to the production of a parasitic reaction, wherein the end of the erasure pulse is determined by the instant at which the electrode--counter-electrode voltage rises to the threshold voltage corresponding to the production of a parasitic reaction.
Claim 3
Dependent Claim
21 words
A method of control according to claim 1, wherein the erasure voltage applied is lower than the parasitic reaction threshold voltage.
Claim 4
Dependent Claim
27 words
A method of control according to claim 1, wherein the electrolyte has a metal halide base, said parasitic reaction being the electrochemical formation of the corresponding halogen.
Claim 5
Dependent Claim
25 words
A method of control according to claim 1, wherein said method consists in applying an erasure voltage of slightly higher value than said threshold voltage.
Claim 6
Dependent Claim
25 words
A method according to claim 1, wherein the erasure voltage is controlled in dependence on the impedance of a reference electrode placed within the cell.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-09 | 1984-09-08 | 1985-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-09 | 1988-09-08 | 1989-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-09 | 1992-09-08 | 1993-03-10 | $7700.00 | Window Closed / Lapsed |