Residual DC voltage evaluation

Patent Pending A residual DC voltage evaluating method for evaluating residual DC voltage produced in a liquid crystal cell comprising a liquid crystal held between oriented films, in which a plurality of sets of a combination of voltage applying time t during which a voltage is applied to the liquid crystal cell externally with a residual DC voltage VrDC produced by applying a voltage during the voltage applying time t are measured, and the measurements plotted at a plurality of points as reference signs (30) are curve-fitted using the expression 1.