abstract |
An improved electro-optic device for rearview mirror for motor vehicles and windows, the device incorporating a multi-layer transparent electrode having a first layer of tin-doped indium oxide and a second layer of fluorine-doped tin oxide. This multi-layer transparent conductive coating stack, which may also include additional coatings to provide color suppression, exhibits sheet resistances as low as about 10Ω/□, while still being high in visible light transmission. This coating stack has surprising advantages for use in electro-optic devices. First, ITO base coat provides low sheet resistance and high light transmission, which is particularly valuable for large area electro-optic mirrors and windows, where resistance in the transparent coating limits speed and uniformity of coloration. Second, the FTO over-coat provides significant processing and environmental stability improvements as compared with ITO alone, and further allows the ITO/FTO stack to maintain low sheet resistance and high light transmission during and after the process steps used to make an electro-optic device. |