Patent ID: 7804472

Claim:
A liquid crystal display panel, comprising: pixel electrodes which are arranged in a two-dimensional matrix; an active matrix substrate which includes switching elements arranged in a matrix in a one-to-one relationship with the pixel electrodes to control application and interruption of a voltage to the pixel electrodes; an opposing substrate which includes a common electrode opposing the pixel electrodes; and a liquid crystal layer disposed between the pixel electrodes and the common electrode, the liquid crystal layer showing cholesteric phase at a temperature of 25° C., wherein different voltages are applied to the liquid crystal layer in each of 1) an image erasing period, 2) an image writing period and 3) an image displaying period, and thereby a state of the liquid crystal layer is changed in an order of erasing an image, writing an image and displaying an image, wherein a first time period Tw of applying a writing voltage, wherein the writing voltage has a value that ranges from a maximum voltage Vh for writing a desired maximum reflectance for the liquid crystal layer at a predetermined temperature to a minimum voltage V 1 for writing a desired minimum reflectance for the liquid crystal layer at the predetermined temperature, to the liquid crystal layer during the image writing period, wherein the first time period is set to be at least as long as a second time period of applying the writing voltage to the liquid crystal layer in which ΔVs for the second time period is less than or equal to a predetermined value, wherein ΔVs is defined to be an absolute value of a difference of 1) a first writing voltage for obtaining approximately 50% of a maximum reflectance for the liquid crystal layer at 40° C. and 2) a second writing voltage for obtaining approximately 50% of a maximum reflectance for the liquid crystal layer at 10° C., wherein the predetermined value is 10% of an absolute difference between Vh and Vl.