Liquid crystal display apparatus, drive circuit therefor, and drive method therefor

摘要

A liquid crystal display apparatus is disclosed, which is capable of suppressing sound emission caused by the AC drive of liquid crystal while suppressing an increase in power consumption. A non-active period during which polarity reversal of a common electrode signal (VCOM) is repeated at predetermined intervals is provided in each horizontal scanning period. During an active period, a common electrode drive circuit provides a common electrode signal (VCOM) indicating either one of potentials LV1 and LV2 to a common electrode, based on a polarity instruction signal (POL). During the non-active period, the common electrode drive circuit provides a common electrode signal (VCOM) whose potential changes between LV3 and LV4 to the common electrode, based on a reversal timing control signal (CTRL). Here, the amplitude of the common electrode signal (VCOM) for the non-active period is made smaller than the amplitude of the common electrode signal (VCOM) for the active period.

主权项

1. A liquid crystal display apparatus comprising:
a plurality of video signal lines for transmitting video signals representing an image to be displayed; a plurality of scanning signal lines intersecting the plurality of video signal lines; a video signal line drive circuit that applies the video signals to the plurality of video signal lines; a scanning signal line drive circuit that selectively drives the plurality of scanning signal lines every horizontal scanning period; a plurality of pixel electrodes arranged in a matrix form at respective intersection portions of the plurality of video signal lines and the plurality of scanning signal lines; a common electrode arranged to face the plurality of pixel electrodes, so as to apply a voltage between the plurality of pixel electrodes and the common electrode; a common electrode drive circuit that drives the common electrode and includes a common electrode potential generating unit that generates a first potential, a second potential, a third potential group, and a fourth potential group, the first potential being a low-level side potential to be provided to the common electrode, the second potential being a high-level side potential to be provided to the common electrode, the third potential group including one or more low-level side potentials having a higher level than the first potential, to be provided to the common electrode, and the fourth potential group including one or more high-level side potentials having a lower level than the second potential, to be provided to the common electrode, wherein the common electrode drive circuit,
alternately provides, during a first period of a horizontal scanning period, the first potential and the second potential to the common electrode every horizontal scanning period, the horizontal scanning period including the first period and a second period, andalternately provides, during the second period, the potentials included in the third potential group and the potentials included in the fourth potential group to the common electrode in each horizontal scanning period; a third potential selecting unit that selects any of the potentials included in the third potential group, based on first setting information which can be set externally; and a fourth potential selecting unit that selects any of the potentials included in the fourth potential group, based on second setting information which can be set externally, wherein
during the second period, the common electrode drive circuit provides the potential selected by the third potential selecting unit and the potential selected by the fourth potential selecting unit to the common electrode.