Electrochromic mirrors and other electrooptic devices

• US 20040233537A1
• Filed: 03/04/2004
• Published: 11/25/2004
• Est. Priority Date: 03/05/2003
• Status: Active Grant

• Current Assignee: Ajjer, LLC
• Original Assignee: Electrochromix, Inc.
• Inventors: Agrawal, Anoop, Cronin, John P., LeCompte, Robert S., Tonazzi, Juan Carlos Lopez
• Granted Patent: US 7,300,166 B2
• Time in Patent Office: Days
• US Class Current: 359/604
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: C09J 163/00 Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1525 characterised by a particular ion transporting layer, e.g. electrolyte
• CPC Class Codes: G02F 1/161 Gaskets; Spacers; Sealing of cells; Filling or closing of cells
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

This invention focuses on electrooptic devices and in particular on electrochromic devices with many aspects directed towards automotive EC mirrors. There are several ways to improve these products and their processing using this invention and some of the prominent ones are outlined below. This invention improves on the devices by disclosing new compositions for electrodes and methods of depositing them. It also addresses novel ways to provide busbars to power these devices in order to improve their performance. The device processing attributes and performance are also improved by adhesive compositions and solid electrolytes disclosed herein. In addition sensors are also disclosed which are novel for use in electrochromic mirrors. The invention also discloses how the electrolytes comprising ionic liquids have no adverse effect on attributes of commercial EC mirrors and often result in improved performance and/or feature enhancements.

Claims

1. A process for assembling an electrochromic device, wherein the device comprises a rear element and a transparent front element being sealably bonded together in a spaced apart relationship to define a chamber, comprising the steps of injecting an electrolyte comprising a polymer formulation into the chamber at elevated temperature, the polymer formulation being of a type that upon cooling will solidify the electrolyte by multiphase formation.

2. A process for assembling an electrochromic device as set forth in claim 1 where the electrochromic device is a mirror.

3. A process for assembling an electrochromic device as set forth in claim 1, where the polymer formulation includes a block copolymer.

4. A process for assembling an electrochromic device as set forth in claim 1, where the polymer formulation is capable of crystallizing as the electrolyte solidifies by multiphase formation.

5. A single compartment electrochromic mirror assembly, wherein the assembly comprises a rear element and a transparent front element being sealably bonded together in a spaced apart relationship to define a chamber, and a solid electrolyte material contained in the said chamber, wherein the said solid electrolyte includes a multiphase solid.

6. A single compartment electrochromic assembly as in claim 5, wherein the said solid electrolyte is a thermoplastic.

7. A single compartment electrochromic assembly as in claim 5, wherein the solid electrolyte includes a block copolymer.

8. A single compartment electrochromic assembly as in claim 5, wherein the solid electrolyte includes a fluorinated polymer.

9. An electrochromic mirror assembly, comprising a rear reflective element and a transparent front element being sealably bonded together in a spaced apart relationship to define a chamber, and an electrochromic material contained in the said chamber, wherein a perimeter busbar for the transparent front element occupies more than 50 percent of the said mirror assembly perimeter, and a perimeter conductive connector for the reflective rear element occupies less than 50 percent of the said mirror assembly perimeter.

10. An electrochromic mirror assembly as set forth in claim 9, where the transparent front element surface facing within the said chamber is coated with transparent electronically conductive material, and the rear reflective element surface facing within the said chamber is coated with a reflective material which is conductive.

11. An electrochromic mirror assembly as set forth in claim 10, where the conductivity of the said transparent electronically conductive material is less than 200 ohms/square and the conductivity of the said conductive reflective material on the rear reflective element surface is less than 10 ohms/square.

12. An automotive variable reflectivity mirror system, comprising at least one interior mirror and one exterior mirror wherein their reflectivity is automatically controlled at night by a first control mechanism in response to rear glare and at least one of these mirrors reverts automatically to a second control mechanism during the daytime.

13. An automotive variable reflectivity mirror system as set forth in claim 12, where the interior and exterior mirrors are electrochromic.

14. An automotive variable reflectivity mirror system as set forth in claim 12, wherein the exterior mirror reverts to a second control mechanism during the daytime

15. An automotive variable reflectivity mirror system as set forth in claim 14, where the second control mechanism is manual.

16. An electrochromic device, comprising an automotive variable reflectivity electrochromic mirror that darkens both during the day and at night, and wherein the lowest reflectivity of the electrochromic mirror at night is lower than the lowest reflectivity during the day.

17. An automotive variable reflectivity mirror system as set forth in claim 16, wherein the electrochromic mirror has a coloring voltage applied thereto, and wherein the coloring voltage applied to the electrochromic mirror during the daytime being in the range of 0.6 to 0.9 V and during the night time the coloring voltage being between 0.6 and 1.4 V.

18. An electrochromic device as set forth in claim 16, wherein the electrochromic mirror is an exterior mirror.

19. An electrochromic assembly, comprising a rear element and a transparent front element bonded together by a sealant in a spaced apart relationship to define a chamber, and an electrochromic material contained in the said chamber, the said sealant comprising an epoxy resin formulation having (a) latent curing property, (b) glass transition temperature in cured state in excess of 120°

C. and (c) an inorganic content of greater than 35%.

20. An electrochromic assembly as in claim 19, where the said sealant comprises crystalline nano-particles of inorganic materials.

21. An electrochromic assembly as in claim 19, where the said sealant comprises UV stabilizers.

22. An electrochromic assembly as in claim 19, where the sealant comprises spacer beads formed of crystalline materials.

23. An electrochromic assembly as in claim 19, where the epoxy formulation comprises filler taken from a group comprising carbon black, fumed silica, colorants, inorganic fillers and oxygen scavengers.

24. An electrochromic mirror assembly, comprising a rear element and a transparent front element bonded together by a sealant in a spaced apart relationship to define a chamber, and an electrochromic material contained in the said chamber, the said sealant comprising an anhydride curing agent and the Tg of the cured sealant being in excess of 120°

C.

25. An electrooptic assembly, comprising a rear element and a transparent front element bonded together by a primerless sealant in a spaced apart relationship to define a chamber, and an electrooptic material contained in the said chamber, the said sealant comprising a prehydrolyzed silane.

26. An electrooptic assembly as set forth in claim 25 where the said assembly is an electrochromic mirror.

27. An electrochromic assembly, comprising a rear element and a transparent front element bonded together by a sealant in a spaced apart relationship to define a chamber, and an electrochromic material contained in the said chamber, the said sealant comprising at least one of (a) crystalline nano-particles of inorganic materials and (b) silsesquioxanes.

28. An electrochromic assembly, comprising a rear element and a transparent front element bonded together by a sealant in a spaced apart relationship to define a chamber, and an electrochromic material contained in the said chamber, the said sealant comprising spacer beads formed of crystalline materials.

29. A process for applying a reflective layer on the surface of a substrate to be used for assembling an electrochromic mirror, comprising the steps of high energy activation of the said surface and deposition of the said reflective layer on the surface, wherein the substrate is not exposed to ambient atmosphere between the steps of high energy activation and deposition of the reflective layer.

30. The process of claim 29 wherein the high energy activation step comprises a treatment step taken from a group comprising plasma treatment and ion treatment.

31. A process as defined in claim 29 where the said step of deposition of the reflective layer is accompanied by high-energy activation of the surface in the chamber that is not exposed to ambient atmosphere.

32. A process as set forth in claim 29, wherein said substrate comprises an inorganic glass substrate.

33. A process for depositing a conductive layer for an electrochromic mirror assembly, comprising the steps of physical vapor deposition of the conductive layer on a substrate accompanied by ion treatment of the substrate, where the energy of the ions in the said ion treatment step is less than 500 eV.

34. A process as set forth in claim 33, where the said process is used to deposit at least one of a reflective metal conductive layer and a transparent conductive layer.

35. A sensor system for controlling reflectivity of automatic variable reflectivity mirrors, comprising at least one electronic light sensor for measurement of glare or ambient-light, wherein such sensor outputs the intensity of light as a frequency signal.

36. An electrochromic mirror assembly with indicator, comprising a rear element and a transparent front element and being sealably bonded together in a spaced apart relationship to define a chamber, and an electrochromic material and an electrolyte contained in the said chamber, and one of the surfaces of the said elements facing within the chamber having a transparent conductive electrode and the surface of the other said element facing within the chamber having a conductive electrode, and wherein an indicator is printed on one of the conductive electrodes from a material which is both electrically conductive and optically absorptive.

37. An electrochromic mirror assembly with indicator as set forth in claim 36, wherein the said printed material has a refractive index that matches the refractive index of one of (a) the conductive electrodes on which the indicator is printed, or (b) the electrolyte.

38. An electrochromic mirror assembly, comprising a rear element and a transparent front element and being sealably bonded together in a spaced apart relationship to define a chamber, and an electrochromic material contained in the said chamber, and the surface of the said front element facing within the chamber having a transparent conductor electrode layer and the surface of the said rear element facing within the chamber having a conductive reflector electrode layer chosen from one of (a) silver alloyed with a lanthanide element and (b) aluminum alloyed with at least one of manganese, iron, silicon, magnesium, zinc and chromium.

39. An electrochromic mirror assembly as set forth in claim 38, where the said reflective electrode layer is overcoated with a transparent conductor layer.

40. An electrochromic mirror assembly as set forth in claim 38, where a tie layer is imposed between the reflective electrode layer and the surface of the said rear element.

41. An electrochromic mirror assembly, comprising a rear element and a transparent front element and being sealably bonded together in a spaced apart relationship to define a chamber, and an electrolyte material contained in the said chamber, and at least one of the surfaces of the said elements facing within the chamber having a transparent conductor comprising an alloy of aluminum oxide and zinc oxide.

42. An electrochromic mirror assembly as set forth in claim 41 wherein a reflective layer is disposed between said transparent conductor and said one surface.