Display device, its driving circuit, and driving method

An active matrix-type display device comprising:

• a plurality of video signal lines for transmitting a video signal based on an image to be displayed;
• a plurality of scanning signal lines crossing the plurality of video signal lines;
• a plurality of switch elements disposed in a matrix respectively in correspondence with intersections of the plurality of video signal lines and the plurality of scanning signal lines;
• a plurality of pixel electrodes respectively connected to the plurality of switch elements;
• a common electrode commonly provided for the plurality of pixel electrodes;
• a video signal line driving circuit for applying the video signal to the plurality of video signal lines so that polarity of potential of the plurality of pixel electrodes for the potential of the common electrode is inverted every first number of horizontal scanning periods;
• and
• a transition period video signal potential determining unit for determining potential of a video signal to be applied to the plurality of video signal lines in a transition period in a frame period made of an effective video period and a vertical blanking period and in which displaying an image of one frame is performed, the transition period being a period in which a time is passed from a start time point of the vertical blanking period, wherein the transition period video signal potential determining unit is configured to determine potential of a video signal to be applied to the plurality of video signal lines in the transition period so that, in first and second frame periods as successive two frame periods, a potential of a video signal at the end time point of the transition period in the first frame period and a potential of a video signal at the end time point of the transition period in the second frame period become almost equal to each other and
• potential of the common electrode is set to be high potential and low potential alternately every first number of horizontal scanning periods,
• length of the transition period in the first frame period and length of the transition period in the second frame period are set to be different from each other, and
• the transition period video signal potential determining unit determines potential of a video signal to be applied to the plurality of video signal lines in the transition period so that, when potential of the common electrode is set as high potential immediately after start of the transition period in the first frame period, potential of the video signal at the end time point of the transition period in the first frame period becomes equal to maximum potential of the video signal in the effective video period and potential of the video signal at the end time point of the transition period in the second frame period becomes equal to maximum potential of the video signal in the effective video period, and
• determine potential of a video signal to be applied to the plurality of video signal lines in the transition period so that, when potential of the common electrode is set as low potential immediately after start of the transition period in the first frame period, potential of the video signal at the end time point of the transition period in the first frame period becomes equal to minimum potential of the video signal in the effective video period and potential of the video signal at the end time point of the transition period in the second frame period becomes equal to minimum potential of the video signal in the effective video period.

A driving circuit of an active matrix-type display device including a plurality of video signal lines for transmitting a video signal based on an image to be displayed, a plurality of scanning signal lines crossing the plurality of video signal lines, a plurality of switch elements disposed in a matrix respectively in correspondence with intersections of the plurality of video signal lines and the plurality of scanning signal lines, a plurality of pixel electrodes respectively connected to the plurality of switch elements, and a common electrode commonly provided for the plurality of pixel electrodes, the driving circuit comprising:

• a video signal line driving circuit for applying the video signal to the plurality of video signal lines so that polarity of potential of the plurality of pixel electrodes for the potential of the common electrode is inverted every first number of horizontal scanning periods;
• and
• a transition period video signal potential determining unit provided on the inside or outside of the video signal line driving circuit and determining potential of a video signal to be applied to the plurality of video signal lines in a transition period in a frame period made of an effective video period and a vertical blanking period and in which displaying an image of one frame is performed, the transition period being a length of a horizontal scanning period and a period in which a time is passed from start time point of the vertical blanking period, wherein from an end time point of the transition period in a preceding frame period of two successive frame periods to a start point of the effective video period in a subsequent frame period, the video signal line driving circuit and the plurality of video signal lines are electrically separated from each other.

A driving circuit of an active matrix-type display device including a plurality of video signal lines for transmitting a video signal based on an image to be displayed, a plurality of scanning signal lines crossing the plurality of video signal lines, a plurality of switch elements disposed in a matrix respectively in correspondence with intersections of the plurality of video signal lines and the plurality of scanning signal lines, a plurality of pixel electrodes respectively connected to the plurality of switch elements, and a common electrode commonly provided for the plurality of pixel electrodes, the driving circuit comprising:

• a video signal line driving circuit for applying the video signal to the plurality of video signal lines so that polarity of potential of the plurality of pixel electrodes for the potential of the common electrode is inverted every number of horizontal scanning periods;
• and
• a transition period video signal potential determining unit provided on the inside or outside of the video signal line driving circuit and determining potential of a video signal to be applied to the plurality of video signal lines in a transition period in a frame period made of an effective video period and a vertical blanking period and in which displaying an image of one frame is performed, the transition period being a period in which a time is passed from start time point of the vertical blanking period, wherein the transition period video signal potential determining unit is configured to determine potential of a video signal to be applied to the plurality of video signal lines in the transition period so that, in first and second frame periods as successive two frame periods, a potential of a video signal at the end time point of the transition period in the first frame period and a potential of a video signal at the end time point of the transition period in the second frame period become almost equal to each other and
• potential of the common electrode is set to be high potential and low potential alternately every first number of horizontal scanning periods,
• length of the transition period in the first frame period and length of the transition period in the second frame period are set to be different from each other, and
• the transition period video signal potential determining unit is configured to determine potential of a video signal to be applied to the plurality of video signal lines in the transition period so that, when potential of the common electrode is set as high potential immediately after start of the transition period in the first frame period, potential of the video signal at the end time point of the transition period in the first frame period becomes equal to maximum potential of the video signal in the effective video period and potential of the video signal at the end time point of the transition period in the second frame period becomes equal to maximum potential of the video signal in the effective video period, and
• determine potential of a video signal to be applied to the plurality of video signal lines in the transition period so that, when potential of the common electrode is set as low potential immediately after start of the transition period in the first frame period, potential of the video signal at the end time point of the transition period in the first frame period becomes equal to minimum potential of the video signal in the effective video period and potential of the video signal at the end time point of the transition period in the second frame period becomes equal to minimum potential of the video signal in the effective video period.

A driving method of an active matrix-type display device including a plurality of video signal lines for transmitting a video signal based on an image to be displayed, a plurality of scanning signal lines crossing the plurality of video signal lines, a plurality of switch elements disposed in a matrix respectively in correspondence with intersections of the plurality of video signal lines and the plurality of scanning signal lines, a plurality of pixel electrodes respectively connected to the plurality of switch elements, and a common electrode commonly provided for the plurality of pixel electrodes, the method comprising:

• a video signal line driving step of applying the video signal to the plurality of video signal lines so that polarity of potential of the plurality of pixel electrodes for the potential of the common electrode is inverted every first number of horizontal scanning periods;
• a transition period video signal potential determining step of determining potential of a video signal to be applied to the plurality of video signal lines in a transition period in a frame period made of an effective video period and a vertical blanking period and in which displaying an image of one frame is performed, the transition period being a length of a horizontal scanning period and a period in which a time is passed from start time point of the vertical blanking period;
• and
• electrically separating the video signal line driving circuit and the plurality of video signal lines from an end time point of the transition period in a preceding frame period of two successive frame periods to start point of the effective video period in subsequent frame period.

A driving method of an active matrix-type display device including a plurality of video signal lines for transmitting a video signal based on an image to be displayed, a plurality of scanning signal lines crossing the plurality of video signal lines, a plurality of switch elements disposed in a matrix respectively in correspondence with intersections of the plurality of video signal lines and the plurality of scanning signal lines, a plurality of pixel electrodes respectively connected to the plurality of switch elements, and a common electrode commonly provided for the plurality of pixel electrodes, the method comprising:

• a video signal line driving step of applying the video signal to the plurality of video signal lines so that polarity of potential of the plurality of pixel electrodes for the potential of the common electrode is inverted every number of horizontal scanning periods;
• a transition period video signal potential determining step of determining potential of a video signal to be applied to the plurality of video signal lines in a transition period in a frame period made of an effective video period and a vertical blanking period and in which displaying an image of one frame is performed, the transition period being a period in which a time is passed from start time point of the vertical blanking period, wherein in the transition period video signal potential determining step, potential of a video signal to be applied to the plurality of video signal lines in the transition period is determined so that, in first and second frame periods as successive two frame periods, a potential of a video signal at the end time point of the transition period in the first frame period and a potential of a video signal at the end time point of the transition period in the second frame period become almost equal to each other and
• potential of the common electrode is set to be high potential and low potential alternately every first number of horizontal scanning periods,
• length of the transition period in the first frame period and length of the transition period in the second frame period are set to be different from each other, and
• in the transition period video signal potential determining step,
• potential of a video signal to be applied to the plurality of video signal lines in the transition period is determined so that, when potential of the common electrode is set as high potential immediately after start of the transition period in the first frame period, potential of the video signal at the end time point of the transition period in the first frame period becomes equal to maximum potential of the video signal in the effective video period and potential of the video signal at the end time point of the transition period in the second frame period becomes equal to maximum potential of the video signal in the effective video period, and
• potential of a video signal to be applied to the plurality of video signal lines in the transition period is determined so that, when potential of the common electrode is set as low potential immediately after start of the transition period in the first frame period, potential of the video signal at the end time point of the transition period in the first frame period becomes equal to minimum potential of the video signal in the effective video period and potential of the video signal at the end time point of the transition period in the second frame period becomes equal to minimum potential of the video signal in the effective video period.