ELECTROCHROMIC DISPLAY MODULE AND COMPOSITION WITH IMPROVED PERFORMANCE

• US 20100277788A1
• Filed: 05/01/2009
• Published: 11/04/2010
• Est. Priority Date: 05/01/2009
• Status: Active Grant

• Current Assignee: S. A. Gemalto
• Original Assignee: S. A. Gemalto
• Inventors: Brestovansky, Dennis, Webb, Steven Paul, Berry, Craig Richard, Kingery, John Russell
• Granted Patent: US 8,432,601 B2
• Time in Patent Office: Days
• US Class Current: 359/273
• CPC Class Codes: C08L 71/02 Polyalkylene oxides
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions
• CPC Class Codes: G02F 1/161 Gaskets; Spacers; Sealing of cells; Filling or closing of cells
• CPC Class Codes: G02F 2001/164 the electrolyte is made of polymers

Abstract

An electrochromic display module employing a unique combination of architecture and electrochromic composition to provide an extended life to the module. The architecture may involve the use of an extended seal about a perimeter of a display portion where the composition is located. In this manner, the rate of solvent leakage from the composition may be substantially reduced. Additionally, the electrochromic composition itself may make use of particular low volatility solvents and constituent combinations so as to discourage the amount particle generation therein. Ultimately, an electrochromic display module having a useful life of more than about 3 years may be provided.

Claims

1. An electrochromic display device comprising an electrochromic composition, said composition comprising:

a solvent, wherein at least about 50% of said solvent remains in the composition for a duration of at least about 3 years; and

particles generated in the composition, a substantial majority of said particles remaining less than about 150 microns in size for a duration of at least about 3 years.

2. The electrochromic display device of claim 1 further comprising a pixel of a given modulation depth said pixel configured to retain more than about 40% of the given modulation depth for a duration of at least about 3 years.

3. The electrochromic display device of claim 1 wherein said electrochromic composition comprises a solvent having a volatility of less than about 0.03 torr at about 20°

C.

4. The electrochromic display device of claim 1 further comprising:

a display portion for accommodating said electrochromic composition at a surface of a backplane substrate of the device; and

a seal extending from a side of the display portion at a perimeter thereof to beyond about 0.12 inches across the backplane substrate for isolating said electrochromic composition thereat.

5. The electrochromic display device of claim 4 wherein said seal is disposed across a majority of the backplane substrate.

6. The electrochromic display device of claim 1 wherein the solvent is a sulfone.

7. The electrochromic display device of claim 1 wherein the solvent comprises at least about 25% of said electrochromic composition for a duration of at least about 3 years.

8. An electrochromic composition for an electronic display, the composition comprising a substantially soluble polymer solubilized in an electrochemically stable solvent having a volatility of less than about 0.03 torr at about 20°

C.

9. The electrochromic composition of claim 8 wherein the solvent and solubilizable polymer are of a character allowing at least about 25 wt % of the polymer to remain dissolved in the solvent for a duration of at least about 24 hours at about room temperature.

10. The electrochromic composition of claim 8 wherein said solvent is one of a sulfone, ethylene glycol phenyl ether, and propylene glycol phenyl ether.

11. The electrochromic composition of claim 10 wherein the sulfone is tetramethylene sulfone.

12. The electrochromic composition of claim 8 further comprising generated particles, a substantial majority thereof having a size of less than about 150 microns.

13. The electrochromic composition of claim 8 wherein the polymer is 100,000 molecular weight polyethylene oxide.

14. The electrochromic composition of claim 8 wherein said polymer comprises between about 10% and about 15% of the composition and said solvent comprises between about 30% and about 50% of the initial composition.

15. The electrochromic composition of claim 8 comprising less than about 0.5% fumed silica pouring agent.

16. An electrochromic display module sized no larger than a handheld card for daily use, the module comprising:

a backplane substrate;

an electrochromic composition disposed at a display location on said substrate; and

a seal disposed on said backplane substrate about a perimeter of the display location for isolating said electrochromic composition thereat, said seal having an extended portion extending beyond about 0.12 inches away from all sides of the display location along said substrate.

17. The electrochromic display module of claim 16 wherein said seal extends across the majority of said backplane substrate.

18. The electrochromic display module of claim 16 wherein the extended portion extends beyond about 0.5 inches away from a side of the display location along said substrate.

19. The electrochromic display module of claim 16 wherein said seal is an acrylic of between about 3 mils and about 5 mils in thickness.

20. The electrochromic display module of claim 16 wherein said seal is configured for one of minimizing solvent loss from the electrochromic composition, providing broad base support for module layers above the display location, and serving as structural support for processing of the module.

21. The electrochromic display module of claim 20 wherein the minimizing solvent loss includes maintaining at least about half of the solvent for a duration of at least about 3 years.

22. A method comprising:

patterning a backplane substrate with visibly actuatable pixels isolated by a dielectric;

providing an extended seal across a majority of the backplane substrate at a perimeter of a display thereof, the display configured to accommodate the pixels; and

delivering an electrochromic composition to the display which employs a solvent having a volatility of less than about 0.03 torr at about 20°

C.

23. The method of claim 22 wherein said delivering of the electrochromic composition comprises stencil printing.

24. The method of claim 22 wherein the electrochromic composition is configured of sufficient thickening character for said delivering.

25. The method of claim 22 wherein the pixels are of a given modulation depth said pixels configured to retain more than about 40% of the given modulation depth for a duration of at least about 3 years.