Field of the Invention
The invention relates to a technology that generates a display video signal.
Description of the Background Art
In the related art, a liquid crystal display in which an in plane switching method is adopted (in the following, referred to as “IPS liquid crystal display”) is known. Such an IPS liquid crystal display is excellent in view angle characteristics and thus, is used as a display device for various scenes such as a wide screen, a large screen, a portable terminal screen, and a screen for an on-vehicle device.
However, in the related art described above, there is still room for improvement on efficient prevention of a residual image phenomenon.
Specifically, the IPS liquid crystal display has a problem that a residual video characteristic is weak and especially, when an interlace video is displayed, a residual video becomes easy to occur in a specific image. For example, although the residual image phenomenon is generated due to occurrence of charge accumulation caused by impurities contained in a liquid crystal layer by a video signal of a specific image, in a case of a non-interlace video, such charge accumulation is eliminated by polarity inversion of a thin film transistor (TFT) electrode of each frame conducted in general liquid crystal display of an active matrix driving type.
However, in a case of the interlace video, one frame is constituted with two fields of an odd-numbered field and an even-numbered field and thus, the video signal of the specific image becomes different between such fields and charge accumulation cannot be eliminated by the above-described polarity inversion. Especially, in a case where a white solid image and a black solid image of which boundaries extend in the field direction, lines (for example, black in the odd-numbered field and white in the even-numbered field) in which polarities are turned to opposite polarities in the odd-numbered field and the even-numbered field may be generated at those boundaries and in this case, a situation that charge accumulation by polarity inversion becomes easy to occur.