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US4376569A
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Electrolyte for an electrochromic display
Assignee: International Business Machines Corp
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Filing: 1980-05-05
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Granted: 1983-03-15
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Expires: 2000-05-05
Abstract
Abstract An electrolyte for an electrochromic display of the kind in which a persistent colored species of an electrochromic substance in solution is deposited onto a display electrode upon the passage of current therethrough is disclosed. The electrolyte comprises an aqueous solution of a di-alkyl bipyridinium salt and a non-polymeric aliphatic alcohol in which either: (a) both alkyl groups of the bipyridinium salt have an odd number of carbon atoms and the alcohol has an even number of carbon atoms; or (b) both alkyl groups of the bipyridinium salt have an even number of carbon atoms and the alcohol has an odd number of carbon atoms. The presence of an alcohol in the electrolyte inhibits recrystallization (spotting) and non-erasure of the display electrodes. A particularly effective alcohol for 1,1' di-heptyl 4,4' bipyridinium dibromide, which has a severe lifetime problem, is n-hexanol.
Inventors
- 👤 John A. Barltrop
- 👤 Colin L. Bird
- 👤 Gilbert C. S. Collins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:19
CPC Classifications
C; C09; C09K; C09K9/00; C09K9/02; G; G02; G02F; G02F1/00; G02F1/01; G02F1/15; G02F1/1503
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
106 words
An electrolyte for an electrochromic display of the kind in which a persistent colored species of an electrochromic substance in solution is deposited onto a display electrode upon the passage of current therethrough, the electrolyte comprising an electrochromic di-alkyl bipyridinium salt and a non-polymeric monohydric aliphatic alcohol, both in aqueous solution, taken from the group consisting of a and b where (a) both alkyl groups of the bipyridinium salt have seven carbon atoms and the alcohol has and even number of carbon atoms; and (b) both alkyl groups of the bipyridinium salt have six carbon atoms and the alcohol has an odd number of carbon atoms.
Claim 2
Dependent Claim
106 words
An electrolyte for an electrochromic display of the kind in which a persistent colored species of an electrochromic substance in solution is deposited onto a display electrode upon the passage of current therethrough, the electrolyte comprising an electrochromic di-alkyl bipyridinium salt and a non-polymeric monohydric aliphatic alcohol, both in aqueous solution, taken from the group consisting of a and b where (a) both alkyl groups of the bipyridinium salt have seven carbon atoms and the alcohol has and even number of carbon atoms; and (b) both alkyl groups of the bipyridinium salt have six carbon atoms and the alcohol has an odd number of carbon atoms.
Claim 3
Dependent Claim
15 words
An electrolyte as claimed in claim 1 in which the alcohol is a primary alcohol.
Claim 4
Dependent Claim
17 words
An electrolyte as claimed in claim 1 in which the electrochromic salt is a 1,1'-di-n-alkyl-4,4' bipyridinium dibromide.
Claim 5
Dependent Claim
16 words
An electrolyte as claimed in claim 1 in which the electrochromic salt is 1,1'-di-heptyl-4,4' bipyridinium dibromide.
Claim 6
Dependent Claim
20 words
An electrolyte as claimed in claim 1 in which the odd and even numbers of carbon atoms differ by 1.
Claim 7
Dependent Claim
13 words
An electrolyte as claimed in claim 1 in which the alcohol is n-hexanol.
Claim 8
Dependent Claim
18 words
An electrolyte as claimed in claim 6 in which the concentration of n-hexanol is half its saturation concentration.
Claim 9
Dependent Claim
18 words
An electrolyte as claimed in claim 7 in which the concentration of the electrochromic salt is 0.05 M.
Claim 10
Dependent Claim
26 words
An electrolyte as claimed in claim 4 in which the concentration of the electrochromic salt is 0.1 M and the alcohol is n-butanol in saturation concentration.
Claim 11
Dependent Claim
12 words
An electrolyte as claimed in claim 1 wherein the alcohol is cyclo-hexanol.
Claim 12
Dependent Claim
12 words
An electrolyte as claimed in claim 1 wherein the alcohol is 2-methyl-pentan-2-ol.
Claim 13
Dependent Claim
21 words
An electrochromic display cell comprising an array of display electrodes, a counter electrode and an electrolyte as claimed in claim 1.
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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) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |