PURPOSE: To stabilize the potential of a counter electrode by using a porous carbon electrode as the counter electrode and by covering the surface of the electrode with an EC layer.
CONSTITUTION: An electrochromic device (ECD) is composed essentially of a transparent front substrate 1, a spacer 3, a rear substrate 2, a transparent display electrode 4, a tungsten oxide (WO3) layer 5, a counter electrode 6, a light diffusing plate 7, and an electrolytic soln. 8. The porous carbon electrode 6 is immersed in an aqueous soln. of tungstic acid and heat treated to form an EC layer on the surface of the electrode 6. Vanadic acid, molybdic acid or titanic acid may be used in place of the tungstic acid. The electrode 6 is heat treated in the soln. having ≤ about 1 mole concn. of the acid at about 400W800°C for about 1hr. The thickness of the EC layer formed on the surface of the counter electrode by the treatment is several 100W about 100μm.
NAMITA TAIRA
NAKATANI NORIO
