Electrochromic devices and methods

• US 5,757,537 A
• Filed: 11/13/1995
• Issued: 05/26/1998
• Est. Priority Date: 09/04/1991
• Status: Expired due to Term

• Current Assignee: Sage Electrochromics, Inc (Compagnie de Saint-Gobain SA)
• Original Assignee: Sun Active Glass Electrochromics Incorporated
• Inventors: Parkhe, Vijay D., Van Dine, John E., Ellis, Frank B. Jr.
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Lester, Evelyn A.
• Application Number:
  US08/557,386
• Time in Patent Office: 925 Days
• Field of Search: 359/265, 359/268-275
• US Class Current: 359/268
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/1525 characterised by a particular ion transporting layer, e.g. electrolyte
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 1/157 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 2001/1536 additional, e.g. protective, layer inside the cell
• CPC Class Codes: G02F 2202/20 LiNbO3, LiTaO3

Abstract

Electrochromic devices are disclosed which may be used for large surface area applications. The devices utilize optical tuning to minimize optical interference between layers of the structure and to maximize uniform optical transparency. Optical tuning also enables transparent conductive oxide layers to be replaced by thin conductive metal layers, thereby reducing the overall thickness of these devices and facilitating the manufacturing process.

Claims

1. An electrochemic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure, and

enhancing means for enhancing the transmission of radiation through at least one of said electrically conductive layers, said electrochromic material having a first index of refraction, said counterelectrode having a second index of refraction and said transporting means having a third index of refraction, said first, second and third indices of refraction being about equal.

2. An electrochromic device as claimed in claim 1, wherein said electrochromic material is selected from the group consisting of tungsten oxide, niobium oxide, titanium oxide, molybdenum oxide, nickel oxide, iridium oxide, and mixtures thereof.

3. An electrochromic device as claimed in claim 1, wherein said counterelectrode is formed from a material selected from the group consisting of vanadium oxide, niobium oxide, indium oxide, nickel oxide, cobalt oxide, molybdenum oxide, and mixtures thereof.

4. An electrochromic device as claimed in claim 1, wherein said transporting means comprises at least one layer formed from an ion conducting material sandwiched between said electrode and said counterelectrode, said ion conducting material including a lithium ion conducting lithium-based ceramic material.

5. An electrochromic device as claimed in claim 1, wherein said transporting means comprises at least one layer formed from an ion conducting material sandwiched between said electrode and said counterelectrode, said ion conducting material including a hydrogen ion conducting material.

6. An electrochromic device as claimed in claim 1, wherein said transporting means comprises at least one layer formed from an ion conducting material sandwiched between said electrode and said counterelectrode, said ion conducting material including a polymer.

7. An electrochromic device as claimed in claim 1, wherein said enhancing means comprises at least one layer of an optically transparent material for enhancing the transmission of radiation through said at least one electrically conductive layer and at least one other layer of an optically transparent material for enhancing the transmission of radiation through another one of said electrically conductive layers.

8. An electrochromic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure,

a substrate, and

enhancing means for enhancing the transmission of radiation through at least one of said electrically conductive layers, said enhancing means including a series of optically transparent layers beginning with a first optically transparent layer arranged between said substrate and said at least one electrically conductive layer and ending with an nth optically transparent layer arranged between said substrate and said first optically transparent layer, said at least one electrically conductive layer having a first index of refraction, said substrate having a second index of refraction less than said first index of refraction, said first optically transparent layer having a third index of refraction less than said first index of refraction, said nth optically transparent layer having a fourth index of refraction greater than said second index of refraction, and said index of refraction of each one of said series of optically transparent layers decreasing monotonically from said third index of refraction to said fourth index of refraction.

9. An electrochromic device as claimed in claim 8, wherein said enhancing means further comprises at least one other layer of an optically transparent material for enhancing the transmission of radiation through another one of said electrically conductive layers.

10. An electrochromic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure, and

enhancing means for enhancing the transmission of radiation through at least one of said electrically conductive layers, said enhancing means including two optically transparent layers, one of said optically transparent layers being proximate to said at least one electrically conductive layer and another one of said optically transparent layers being distal to said at least one electrically conductive layer, said at least one electrically conductive layer having a first index of refraction, said one of said optically transparent layers having an index of refraction which is less than said first index of refraction, and said another one of said optically transparent layers having an index of refraction which is greater than said index of refraction of said one of said optically transparent layers.

11. An electrochromic device as claimed in claim 10, wherein said one of said optically transparent layers has an index of refraction between about 1.4 and about 1.7, and said another of said optically transparent layers has an index of refraction about equal to or greater than said first index of refraction.

12. An electrochromic device as claimed in claim 10, wherein said two optically transparent layers have a combined thickness of between about 30 nm and about 70 nm.

13. An electrochromic device as claimed in claim 10, wherein said enhancing means further comprises at least one other layer of an optically transparent material for enhancing the transmission of radiation through another one of said electrically conductive layers.

32. An electrochromic device as claimed in claim 10, further comprising a substrate cooperating with said at least one of said electrically conductive layers to sandwich said two optically transparent layers.

33. An electrochromic device as claimed in claim 32, further comprising a superstrate cooperating with said substrate to sandwich said electrochromic structure and said electrically conductive layers.

14. An electrochromic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure, at least one of said electrically conductive layers including a layer of an electrically conductive oxide, and

enhancing means for enhancing the transmission of radiation through said electrically conductive oxide layer, said electrochromic material having a first index of refraction, said counterelectrode having a second index of refraction, said transporting means having a third index of refraction, and said electrically conductive oxide layer having a fourth index of refraction, said first, second, third and fourth indices of refraction being about equal.

15. An electrochromic device as claimed in claim 14, wherein said enhancing means comprises at least one layer of an optically transparent material for enhancing the transmission of radiation through said electrically conductive oxide layer and at least one other layer of an optically transparent material for enhancing the transmission of radiation through another one of said electrically conductive layers.

16. An electrochromic combination, comprising

a transparent substrate, and

an electrochromic device arranged on said transparent substrate, said electrochromic device including an electrochromic structure having an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode, conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure, and enhancing means for enhancing the transmission of radiation through at least one of said electrically conductive layers, said electrochromic material having a first index of refraction, said counterelectrode having a second index of refraction and said transporting means having a third index of refraction, said first, second and third indices of refraction being about equal.

17. An electrochromic combination as claimed in claim 16, wherein said enhancing means comprises at least one layer of an optically transparent material arranged between said transparent substrate and said electrochromic device for enhancing the transmission of radiation through said at least one electrically conductive layer, and at least one other layer of an optically transparent material for enhancing the transmission of radiation through another one of said electrically conductive layers.

18. An electrochromic combination as claimed in claim 16, further comprising a transparent superstrate, wherein said electrochromic device is sandwiched between said transparent substrate and said transparent superstrate.

19. An electrochromic combination as claimed in claim 18, wherein said enhancing means comprises at least one layer of an optically transparent material arranged between said transparent substrate and said electrochromic device for enhancing the transmission of radiation through said at least one electrically conductive layer, and at least one other layer of an optically transparent material arranged between said transparent superstrate and said electrochromic device for enhancing the transmission of radiation through another one of said electrically conductive layers.

20. An electrochromic combination as claimed in claim 18, further comprising a layer of an adhesive material for binding said transparent superstrate to said electrochromic device.

21. An electrochromic combination as claimed in claim 20, wherein said adhesive layer has an index of refraction between about 1.4 and about 1.8.

22. An electrochromic combination as claimed in claim 20, wherein said transparent superstrate has an index of refraction and said adhesive layer has an index of refraction which is substantially equal to said index of refraction of said transparent superstrate.

23. An electrochromic combination as claimed in claim 20, wherein another of said electrically conductive layers includes a layer of an electrically conductive oxide and said adhesive layer is in surface contact with said electrically conductive oxide layer.

24. An electrochromic combination as claimed in claim 23, wherein said electrically conductive oxide layer has one index of refraction, said transparent superstrate has another index of refraction, and said adhesive layer has an index of refraction between said one and said another indices of refraction.

25. An electrochromic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure,

a substrate, and

enhancing means including at least one layer of an optically transparent material arranged between said substrate and at least one of said electrically conductive layers for enhancing the transmission of radiation through said at least one electrically conductive layer, said substrate having a first index of refraction, said at least one electrically conductive layer having a second index of refraction, and said enhancing means having a third index of refraction about equal to the square root of the mathematical product of said first and second indices of refraction.

26. An electrochromic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure,

a substrate, and

enhancing means including at least one layer of an optically transparent material arranged between said substrate and at least one of said electrically conductive layers for enhancing the transmission of radiation through said at least one electrically conductive layer, said enhancing means having a thickness between about 60 nm and about 90 nm, said substrate having a first index of refraction, said at least one electrically conductive layer having a second index of refraction, and said enhancing means having a third index of refraction between said first and second indices of refraction.

27. An electrochromic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure,

a substrate, and

enhancing means including at least one layer of an optically transparent material arranged between said substrate and at least one of said electrically conductive layers for enhancing the transmission of radiation through said at least one electrically conductive layer, said substrate having a first index of refraction, said at least one electrically conductive layer having a second index of refraction, and said enhancing means having a third index of refraction between said first and second indices of refraction, said enhancing means having a thickness which is inversely proportional to said third index of refraction.

28. An electrochromic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode, said transporting means including at least one layer formed from an ion conducting material sandwiched between said electrode and said counterelectrode, said ion conducting material including a polymer,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure,

a substrate, and

enhancing means including at least one layer of an optically transparent material arranged between said substrate and at least one of said electrically conductive layers for enhancing the transmission of radiation through said at least one electrically conductive layer, said substrate having a first index of refraction, said at least one electrically conductive layer having a second index of refraction, and said enhancing means having a third index of refraction between said first and second indices of refraction.

29. An electrochromic device as claimed in claim 28, wherein said enhancing means further comprises at least one other layer of an optically transparent material for enhancing the transmission of radiation through another one of said electrically conductive layers.

30. An electrochromic device, comprising

an electrochromic structure including an electrode formed from an electrochromic material, a counterelectrode and transporting means for transporting ions between said electrode and said counterelectrode,

conductive means including at least two electrically conductive layers sandwiching said electrochromic structure for applying an electric potential across said electrochromic structure,

a substrate, and

enhancing means including at least two optically transparent layers arranged between said substrate and at least one of said electrically conductive layers for enhancing the transmission of radiation through said at least one electrically conductive layer, one of said optically transparent layers being proximate to said at least one electrically conductive layer and another one of said optically transparent layers being distal to said at least one electrically conductive layer, said substrate having a first index of refraction, said at least one electrically conductive layer having a second index of refraction, said enhancing means having a third index of refraction between said first and second indices of refraction, said one of said optically transparent layers having an index of refraction which is less than said second index of refraction, and said another one of said optically transparent layers having an index of refraction which is greater than said index of refraction of said one of said optically transparent layers.

31. An electrochromic device as claimed in claim 30, wherein said enhancing means has a thickness between about 30 nm and about 70 nm.