SYSTEM FOR DRIVING ELECTROCHROMIC ELEMENT

摘要

PURPOSE:To obtain a desired transmittance over a long period of time by connecting resistances having the resistance value conformed to the fluctuation in the coloring performance of the elements between one calculation circuit backup power source and the respective chromic elements in series and impressing the same voltage as a reference voltage to the elements. CONSTITUTION:Constant current of 150mA is passed for 100sec to the chromic element 1 in a driving circuit 3 for coloring and decoloring by turning on a switch 2 in such a manner that the transmittance attains 20%. 1min later, the switch 2 is turned off and a switch 4 is turned on. The voltage corresponding to the temp. of the element 1 is selected from the temp. data from a temp. sensor 5 and the characteristics of the transmittance-voltage between the chromic electrode and counter electrode at -20-+120 deg.C stored in the calculation circuit backup power source 6. This voltage is impressed to the element 1. Then, the initially set 20% transmittance is kept within the range of about + or -3% range even if the ambient temp. changes between -20-+120 deg.C in 24hr after the coloration. No abnormality is thus admitted in the coloring and decoloring state.