Electrochromic display device with improved erasing characteristic

摘要

An electrochromic device having an electrochromic layer of persistent electrochromic material such as tungsten oxide, and an electrolyte layer and a counter electrode which comprises an oxidizing agent which has oxidizing electrode potential more negative than the electrochromic layer to provide a stored charge for erasing color from the electrochromic layer, and to increase the emf of the charge used for the erase function. Examples of suitable oxidizing agents are manganese dioxide and chromic oxide.