Patent ID: 7651228

Claim:
An interior rearview mirror assembly suitable for use in a vehicle, said mirror assembly comprising: a variable reflectance element, said variable reflectance element including an electrochromic medium disposed between a first sheet and a second sheet, said first sheet having a transparent conductive coating on its side contacted by said electrochromic medium, said second sheet having a metallic mirror reflector on its side contacted by said electrochromic medium, said metallic minor reflector of said variable reflectance element being partially transmissive to visible light; an information display positioned to the rear of said metallic mirror reflector of said variable reflectance element, said information display comprising backlighting by a plurality of light emitting diodes, wherein said light emitting diodes emit white light; a control for adjusting the luminous intensity of said information display, said control being responsive to a light level sensed by at least one light sensor disposed at said mirror assembly; wherein the presence of said information display rearward of said metallic mirror reflector of said reflectance element is substantially not apparent to a driver of the vehicle viewing said interior rearview mirror assembly as normally mounted in the vehicle until said information display is backlit, and wherein, when said information display is backlit, information displayed by said information display is viewed through said metallic mirror reflector by a driver of the vehicle viewing said interior rearview minor assembly as normally mounted in the vehicle; wherein said control adjusts the luminous intensity of information displayed by said information display to provide, to a driver of the vehicle viewing said interior rearview mirror assembly as normally mounted in the vehicle, a luminous intensity in a range extending from at least about 750 candelas/sq. meter during a daytime condition to less than about 100 candelas/sq. meter during a nighttime condition; and wherein said control adjusts the luminous intensity by use of pulse-width modulation.