ELECTROCHROMIC DISPLAY ELEMENT

摘要

PURPOSE:To lessen the decrease in the quantity of electricity to be implanted and to maintain a high response characteristic without generating unequal displaying even if a display element is subjected to cold-heat temp. cycles by using carbon powder having specific shapes as the carbon powder to be used for a counter electrode material layer of a counter electrode. CONSTITUTION:The material layer 6 of the electrochromic display element is formed of a thin tungsten oxide film and an electrolyte 15 contg. a lithium salt and nonaq. solvent which dissolves said salt is used. The carbon powder which has the specific characteristic of <=5pH of the supernatant liquid obtd. after immersing the powder in 10wt. times pure water and boiling the water for 1.5min and has a proton supplying capacity is used as the carbon power to be used for the counter electrode material layer 10 of the counter electrode 8. The effect of improving the preserving stability of the element is lost if the pH value exceeds 5 and the decrease in the quantity of electricity to be implanted and the degradation of a counter electrode 9 in the initial period are easily generated if the pH value is lower than the limit. The quantity of the electricity to be initially implanted is thereby decreased and the stable high response speed is maintained. The unequal display is prevented even if the element is subjected to the cold heat temp. cycles.