Transparent electrode for an electrochromic switchable cell

• US 20070002422A1
• Filed: 06/22/2006
• Published: 01/04/2007
• Est. Priority Date: 07/01/2005
• Status: Active Grant

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: O'Shaughnessy, Dennis
• Granted Patent: US 7,586,664 B2
• Time in Patent Office: Days
• US Class Current: 359/265
• CPC Class Codes: E06B 2009/2464 featuring transparency control by applying voltage, e.g. LCD, electrochromic panels
• CPC Class Codes: G02F 1/13452 Conductors connecting driver circuitry and terminals of panels
• CPC Class Codes: G02F 1/153 Constructional details
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 1/155 Electrodes
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor
• CPC Class Codes: G02F 2001/1536 additional, e.g. protective, layer inside the cell

Abstract

An electrochromic switchable transparency, e.g. a window and/or a mirror includes an electrochromic switchable medium between a pair of electrode assemblies. At least one of the electrode assemblies is transparent to visible light and includes an electrode over a surface. In one nonlimiting embodiment of the invention, the electrode has two electrically conducting layers and a bridging layer between and interconnecting the two electrically conducting layers. In one nonlimiting embodiment, the bridging layer includes a high electrically resistance connecting layer to provide the electrode with a heating layer to heat the surface and/or a current conducting layer to pass current to the medium. In another nonlimiting embodiment, the bridging layer includes an electrically connecting layer to pass current to electrically enhance the first electrically conductive layer. In another nonlimiting embodiment, the electrically conducting layers are silver films to reduce infrared transmission through the first electrode assembly.

Claims

1. An article comprising;

a first electrode assembly having an electrode defined as a first electrode;

a second electrode assembly having an electrode defined as a second electrode with the first and second electrodes in facing relationship to one another;

a medium between the first and second electrodes, the medium in response to electric stimuli alters percent of visible light transmitted through the medium;

the first electrode assembly having a first major surface facing the medium with the first electrode between the first major surface and the medium, the first electrode comprising;

a first electrically conductive layer between the medium and the first major surface;

a second electrically conductive layer spaced from the first electrically conductive layer and between the first electrically conductive layer and the medium;

first and second electrical contact members spaced from one another and contacting the first electrically conductive layer, wherein the first and second electrical contact members and the first electrically conductive layer provide a first electrically conductive path, and

a third electrical contact member contacting the second electrically conductive layer, and

a fourth electrical contact member contacting the second electrode, wherein the third and fourth electrical contact members, the second electrically conductive layer, the medium and the second electrode provide a second electrically conductive path.

2. The article according to claim 1, wherein the medium is an electrochromic switchable medium and at least one of the electrode assemblies is transparent to wavelengths in the range of 400-700 nanometers.

3. The article according to claim 1, wherein electrical current moving through the first electrically conductive layer heats the first major surface of the first electrode assembly.

4. The article according to claim 1, wherein the first and third electrical contact members are both connected to a positive or negative terminal of a direct current power supply, and the second and fourth electrical contacts are both connected to the negative or positive terminals of the power supply, respectively.

5. The article according to claim 1, wherein the first and second electrical contact members are connected to a first direct current power supply, and the third and fourth electrical contact members are connected to a second direct current power supply.

6. The article according to claim 1, wherein the second electrode assembly has a major surface defined as a second major surface facing the medium with the second electrode between the second major surface and the medium, the second electrode comprising:

an electrically conductive layer defined as a third electrically conductive layer between the medium and the second major surface;

an electrically conductive layer defined as a fourth electrically conductive layer spaced from the third electrically conductive layer and between the third electrically conductive layer and the medium;

the fourth electrical contact contacting the fourth electrically conductive layer; and

fifth and sixth electrical contact members spaced from one another and contacting the third electrically conductive layer wherein the fifth and sixth electrical contact members and the third electrically conductive layer provide a third electrically conductive path.

7. The article according to claim 6, wherein the medium is an electroconductive switchable medium, the first and second electrical contact members comprise first and second bus bars connected to the first electrically conductive layer, the third electrical contact member comprises a third bus bar connected to the second electrically conductive layer, the fourth electrical contact member comprises a fourth bus bar connected to the fourth electrically conductive layer, and the fifth and sixth electrical contact members comprises fifth and sixth bus bar connected to the third electrically conductive layer.

8. The article according to claim 1, wherein the medium is an electrochromic switchable medium and the first electrode assembly passes wavelengths in the range of 400-700 nanometers.

9. The article according to claim 8, further comprising a high electrical resistance connecting layer between and connecting the first and second electrically conductive layers, wherein the connecting layer has a predetermined resistance to electric current flowing along the first electrically conductive layer such that less than 50% of the current moving along the first electrically conductive layer passes through the connecting layer to the second electrically conductive layer.

10. The article according to claim 9, wherein the high electrical resistance connecting layer is an electrically insulating layer.

11. The article according to claim 9, wherein the first electrical contact member and the third electrical contact member is a bus bar that simultaneously provides a current connection for the first and second electrically conductive layers.

12. The article according to claim 9, wherein the first electrical contact member is a first bus bar, the second electrical contact member is a second bus bar, and the third electrical contact member is a third bus bar.

13. The article according to claim 8, further comprising an electrically conductive connecting layer between and connecting the first and second electrically conductive layers, wherein the connecting layer has a predetermined resistance to electric current flowing along the first electrically conductive layer such that at least 50% of the current moving along the first electrically conductive layer passes through the connecting layer to the second electrically conductive layer.

14. The article according to claim 13, wherein the first electrical contact member and the third electrical contact member is a bus bar that simultaneously provides a current connection for the first and second electrically conductive layers.

15. The article according to claim 13, wherein the first electrical contact member comprises a first bus bar, the second electrical contact member comprises a second bus bar, and the third electrical contact member comprises a third bus bar.

16. The article according to claim 1, wherein the medium is an electrochromic switchable medium;

the first electrode assembly passes wavelengths in the range of 400-700 nanometers;

the first major surface is a first major surface of a transparent substrate;

the first electrically conductive layer comprises a first metal layer; and

the second electrically conductive layer comprises a first electrically conductive metal film and a second electrically conductive film in electrical contact with the medium, and further comprising;

a substrate contact layer between the first metal layer and the first major surface of the substrate, and

a connecting layer selected from an electrically conductive connecting layer and a high electrical resistance connecting layer, between the first metal layer of the first electrically conductive layer and the first metal film of the second electrically conductive layer.

17. The article according to claim 16, wherein the substrate is a glass sheet further comprising an opposite second major surface, and further comprising a coating selected from a hydrophobic coating, a hydrophilic coating, a solar control coating and combinations thereof, on at least one of the major surfaces of the glass sheet.

18. The article according to claim 16, wherein a closed frame is between and joined to the electrode assemblies to provide a sealed chamber between the electrode assemblies and the medium comprises an electrochromic switchable medium.

19. The article according to claim 16, wherein the article is selected from:

(A) a transparency of a vehicle of the type selected from the group of (a) land vehicles selected from the group of automobiles, trucks, cars, motorcycles, trains and combinations thereof;

(b) aircraft vehicles;

(c) space vehicles;

(d) above water vehicles;

(e) below water vehicles, and (f) combinations thereof;

(B) windows for structures selected from the group of (a) residential homes;

(b) commercial buildings;

(c) oven doors, (d) microwave doors;

(e) refrigerator doors; and

(f) combinations thereof;

(C) mirrors

(D) vehicular rear view mirrors;

(E) vehicular side view mirrors, and

(F) combinations thereof.

20. The article according to claim 16, wherein the substrate contact layer comprises a support layer and a metal contact layer.

21. The article according to claim 20, wherein the support layer of the substrate contact layer comprises a zinc stannate film, the metal contact layer of the substrate contact layer comprises a zinc oxide film, and the first metal layer of the first electrically contact layer comprises a silver film defined as a first silver film.

22. The article according to claim 21, wherein the zinc stannate film is on the first major surface of the substrate, the zinc oxide film is on the zinc stannate film, and the first silver film is on the zinc oxide layer.

23. The article according to claim 22, wherein the connecting layer is a high electrical resistance connecting layer to electrically insulate the first silver film of the first electrically conductive layer from the first metal film of the second electrically conductive layer.

24. The article according to claim 23, wherein the high electrical resistance connecting layer comprises a dielectric support layer and a metal contact layer.

25. The article according to claim 24, wherein the dielectric support layer of the high electrical resistance connecting layer comprised a dielectric zinc stannate film, the metal contact layer of the high electrical resistance connecting layer comprises a zinc oxide layer, and the metal film of the second electrically conductive layer is a silver film defined as a second silver film.

26. The article according to claim 25, wherein the dielectric zinc stannate film of the high electrical resistance connecting layer is over the first silver film, the zinc oxide film of the high electrical resistance connecting layer is on the dielectric zinc stannate film of the high electrical resistance connecting layer, and the second silver film is on the zinc oxide film of the high electrical resistance connecting layer.

27. The article according to claim 22, wherein the connecting layer is an electrically conductive connecting layer to electrically interconnect the first silver film of the first electrically conductive layer and the first metal film of the second electrically conductive layer.

28. The article according to claim 27, wherein the electrically conductive connecting layer is a current conducting layer to pass at least 50% of the current applied to the first silver film of the first electrically conductive layer to the first metal film of the second electrically conductive layer.

29. The article according to claim 28, wherein the electrically conductive connecting layer comprises a support layer and a metal contact layer.

30. The article according to claim 29, wherein the support layer of the electrically conductive connecting layer is a zinc stannate film, the metal contact layer of the electrically conductive connecting layer is a zinc oxide layer, and the first metal film of the second electrically conductive layer is a silver film defined as a second silver film.

31. The article according to claim 30, wherein the second film of the second electrically conductive layer is a conductive metal oxide film, and the zinc stannate film of the electrically conductive connecting layer is over the first silver film, the zinc oxide film of the electrically conductive connecting layer is on the zinc stannate film of the electrically conductive connecting layer, the second silver film is on the zinc oxide film of the electrically conductive connecting layer, and the second film of the second electrically conductive layer is over the second silver film.

32. The article according to claim 27, wherein the electrically conductive connecting layer comprises a protective film over the first metal layer of the first electrically conducting layer and an electrically conductive ceramic film over the protective film.

33. The article according to claim 32, wherein the protective layer is an oxygen deficient sputtered ceramic film on the first metal layer and the electrically conductive ceramic film is a sputtered ceramic film having more oxygen than the oxygen deficient sputtered ceramic film on the oxygen deficient sputtered ceramic film.

34. The article according to claim 16, further comprising a protective layer on the first metal layer of the first electrically conductive layer and on the first metal film of the second electrically conductive layer.

35. The article according to claim 34, wherein the protective layer on at least one of the first metal layer of the first electrically conductive layer and the first metal film of the second electrically conductive layer is an oxygen deficient sputtered ceramic film.

36. The article according to claim 34, wherein the protective layer on at least one of the first metal layer of the first electrically conductive layer and the first metal film of the second electrically conductive layer is selected from zirconium, titanium, copper, metal oxides, metal nitrides, non-stoichiometric ceramics, titanium nitride and combinations thereof.

37. In an article of the type having a first electrode assembly spaced from a second electrode assembly, and a medium between the first and second electrode assemblies, wherein the medium in response to an electric stimuli alters percent of visible light transmitted through the medium, the improvement comprising:

at least one of the electrode assemblies comprising;

a surface;

a first zinc stannate layer over the surface;

a first zinc oxide layer over the first zinc stannate layer, and

a first metal layer on the first zinc oxide layer.

38. The article according to claim 37, wherein the article is an electrochromic switchable cell and further comprising an electrically conductive layer over the first metal layer and in contact with the medium.

39. The article according to claim 38, further comprising a protective layer between the first metal layer and the conductive layer.

40. The article according to claim 39, wherein the protective layer is an oxygen deficient sputtered ceramic film and the conductive layer is a sputtered ceramic film having more oxygen than the oxygen deficient sputtered ceramic film.

41. The article according to claim 37, wherein the article is an electrochromic switchable cell, and further comprising:

a second zinc stannate layer the over the first metal layer;

a second zinc oxide layer over the second zinc stannate layer;

a second metal layer on the second zinc oxide layer, and

an electrically conductive layer over the second metal film.

42. The article according to claim 41, further comprising a protective layer on the first and second metal layers.

43. The article according to claim 42, wherein the protective layer is selected from zirconium, titanium, copper, metal oxides, metal nitrides, non-stoichiometric ceramics, titanium nitride and combinations thereof.

44. A method of operating an electrochromic switchable cell of the type having a first transparent electrode assembly on a major surface, the first electrode assembly spaced from a second electrode assembly, and an electrochromic switchable medium between the first and second electrode assemblies, the method comprising the steps of:

providing the first electrode assembly with a first electrically conducting layer spaced from the major surface and in electrical contact with the electrochromic switchable medium and a second electrically conductive layer between the first electrically conductive layer and the major surface and spaced from the first electrically conducting layer and the electrochromic switchable medium, and

at selected times, moving current through the first and/or the second electrically conductive layers.

45. The method according to claim 44, wherein the first electrically conducting layer is a first metal layer and the second electrically conducting layer is a second metal layer, and the step of providing at least one electrode assemblies comprises the steps of:

providing a first dielectric layer over the major surface;

providing the second metal layer over the first dielectric layer;

providing a bridging layer over the second metal layer;

providing the first metal layer over the bridging layer; and

providing an electrically conducting metal oxide layer over the first metal layer,

wherein the step of at selected times, moves current through the second metal layer to heat the major surface and moves current through the first metal layer to pass current through the electrochromic medium to the second electrode assembly to alter the visible light transmission of the medium.