Paper counter-electrode for electrochromic devices

• US 4,088,395 A
• Filed: 05/27/1976
• Issued: 05/09/1978
• Est. Priority Date: 05/27/1976
• Status: Expired due to Term

• Current Assignee: American Colloid Company (Minerals Technologies Incorporated)
• Original Assignee: American Colloid Company (Minerals Technologies Incorporated)
• Inventors: Gigila, Robert D.
• Primary Examiner(s): Sikes, William L.
• Application Number:
  US05/690,446
• Time in Patent Office: 712 Days
• Field of Search: 350/160, 29/25.14, 29/25.17
• US Class Current: 359/269
• CPC Class Codes: G02F 1/1523 comprising inorganic material
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor
• CPC Class Codes: G02F 2001/1555 Counter electrode

Abstract

Disclosed is a method for forming a counter-electrode in a variable light modulating device of the electrochromic type. The counter-electrode is a paper composition of fibrous pulp and carbon.

Claims

1. In a variable light modulating device of the electrochromic type having an arrangement comprising a light transmitting substrate having a persistent electrochromic material as a light modulating material and a counter-electrode separated from said electrochromic material by an ion-conducting material, an improved counter-electrode structure consisting essentially of a paper sheet including a web of filaments permeated with carbon.

2. The combination according to claim 1, wherein said filaments are acrylic fibers.

3. The combination according to claim 1 wherein said paper sheet includes a fluorocarbon resin binder material.

4. The combination according to claim 3 wherein said paper sheet includes an electrochromic material.

5. The combination according to claim 4 wherein said electrochromic material is WO₃.

6. A process for making a paper counter-electrode for an electrochromic variable light modulating device comprising:

blending an aqueous suspension of fibrous material with powdered carbon to form an aqueous mixture,

forming a sheet of the solids from said aqueous mixture,

drying and pressing said sheet to form a paper material to be used as a counter-electrode for an electrochromic device.

7. The process of claim 6 wherein said fibrous material is an acrylic fiber.

8. The process of claim 7 wherein a binder is blended into said aqueous mixture so as to form a more cohesive paper sheet.

9. The process of claim 8 wherein said binder is a fluorocarbon resin.

10. The process of claim 9 wherein a flocculating agent and a surfactant are blended into said aqueous mixture.

11. The process of claim 10 including the additional finishing steps of washing the dried and pressed paper sheet in acid and alcohol, and drying the washed sheet.

12. The process of claim 9 including the additional step of applying an electrochromic material to the washed sheet.

13. The process of claim 12 wherein said electrochromic material is WO₃.

14. A paper counter-electrode for an electrochromic light modulating device prepared according to the process of claim 6.

15. A paper counter-electrode for an electrochromic light modulating device prepared according to the process of claim 11.

16. A paper counter-electrode for an electrochromic light modulating device prepared according to the process of claim 12.