Patent ID: 6747622
Filing Date: 2004-06-08
Classification: G09G

Abstract:
A liquid crystal display device comprising:a liquid crystal panel which juxtaposes a plurality of common electrodes extended in the first direction on one of a pair of substrates sandwiching a liquid crystal layer therebetween and juxtaposes a plurality of segment electrodes extended in the second direction transverse to the first direction on the other of the pair of these substrates, a common driver having a common voltage output part which applies scanning signals to the plurality of respective common electrodes, and a segment driver having a segment voltage output part which applies data signals corresponding to display data to the plurality of respective segment electrodes, wherein the common driver has following functions: (a) to allocate selection periods sequentially to the plurality of respective common electrodes and to apply a selection voltage to one of the plurality of common electrodes to which non-selection voltage is applied as scanning signals in a period in which the data signals are applied to the plurality of segment electrodes; (b) to apply the scanning signal to a nMth one of the plurality of common electrodes to which the Mth selection period (M being a natural number of 2 or more) is allocated performed in sequence of (i) ceasing the application of the non-selection voltage to the nMth of common electrode at a first time when the Mth selection period is started, (ii) starting the application of the selection voltage thereto from the second time coming after the first time, (iii) ceasing the application of the selection voltage thereto at the third time when the Mth selection period expires, and (iv) starting the application of the non-selection voltage thereto from the fourth time coming after the third time; (c) to comparing polarity of the selection voltages in the Mth selection period and in a (Mâˆ’1)th selection period allocated prior to the Mth selection period to a nM-1th common electrode and applied to the nM-1th common electrode, respectively for the non-selection voltage; (d) to short-circuit a portion of the common voltage output part corresponding to the nMth common electrode and another portion thereof corresponding to the nM-1th common electrode during a period lying between the first time and the second time, when the selection voltage in the Mth selection period and the selection voltage in the (Mâˆ’1)th selection period have the same polarity, and (e) not to short-circuit the portion of the common voltage output part corresponding to the nMth common electrode and the another portion thereof corresponding to the nM-1th common electrode during the period lying between the first time and the second time, when the selection voltage in the Mth selection period and the selection voltage in the (M=1)th selection period have the polarities opposite to each other.