Electrochromic display device capable of display in plural colors

摘要

In an electrochromic (EC) display device having oppositely arranged two EC electrode layers, two kinds of EC materials each of which takes on a characteristic color by electrochemical oxidation, or by electrochemical reduction, are used in the two EC electrode layers, respectively, on condition that the characteristic color of one EC material differs from the color of the other EC material. For example, Prussian blue which colors in blue by oxidation and polytriphenylamine which colors in bronze by oxidation are used in combination. An alternative example is using a combination of WO3 which colors in blue by reduction and V2O5 which colors in green by reduction. Since electrochemical oxidation of one EC electrode layer is usually accompanied by reduction of the opposite EC electrode layer, this EC device can be operated so as to selectively and alternately exhibit at least two different colors aside from colorless transparency.