Patent ID: 6045724
Filing Date: 2000-04-04
Classification: C09K,G02F

Abstract:
A large area variable transmission electrochromic window suitable for use as at least one of an architectural window, an automotive window, and an office partition panel comprising:first and second spaced optically transparent elements, said elements each having front and rear surfaces and defining a space between the rear surface of said first element and the front surface of said second element;an electrochromic medium confined in said space whose light transmission is variable upon the application of an electric field thereto;means for applying an electric field to said electrochromic medium to cause variation in the light transmittance of said medium wherein said means for applying an electric field include a substantially transparent conductive coating on at least one of said rear surface of said first element and said front surface of said second element, said substantially transparent conductive coating having a sheet resistance of 25 ohms/square or lower and selected from the group consisting of indium tin oxide, doped tin oxide, and doped zinc oxide;said electrochromic medium including a redox chemical pair which colors under the application of voltage;said electrochromic medium further including an ultraviolet stabilizer whereby said redox chemical pair is provided with enhanced ultraviolet stability;said electrochromic window having an electrochromically active large area of length dimension at least about 14 cm and of width dimension at least about 14 cm; said electrochromic window exhibiting a steady state leakage current of less than about 2.68 amperes per square meter when a potential of one volt is applied to said electrochromic window whereby coloration uniformity of said electrochromic window is enhanced.