Patent ID: 7218299

Claim:
A liquid crystal display apparatus comprising: a liquid crystal display element that includes a layer of a liquid crystal exhibiting a cholesteric phase, and a plurality of scanning and signal electrodes extending across each other with the liquid crystal layer therebetween; and a driving device for driving the liquid crystal display element by simple matrix driving, wherein the driving device is configured such that (1) a driving voltage of single polarity including a selection signal voltage, a reset voltage and a maintaining voltage is applied to the scanning electrodes in each frame, and the polarity of the driving voltage is reversed in every frame; (2) the scanning electrodes are successively brought to a selected state by applying the selection signal voltage to each scanning electrode in a scanning period set for the scanning electrode, while a rewriting signal voltage corresponding to each scanning electrode in the selected state is applied to each signal electrode in synchronization with application of the selection signal voltage to the scanning electrode; (3) the reset voltage is applied to the scanning electrode to bring the liquid crystal to a homeotropic state before applying the selection signal voltage, and the maintaining voltage is applied to the scanning electrode to establish a state of the liquid crystal to be selected by the selection signal voltage after applying the selection signal voltage; and (4) the rewriting signal voltage to be applied to the signal electrode is changed in polarity within the scanning period, and effective values of positive voltage and negative voltage of the rewriting signal voltage are substantially equal to each other within the scanning period.