Liquid crystal display device
A liquid crystal display device having superior moving-image display characteristics are provided. In the liquid crystal display device, the timing of application of grayscale voltage to liquid crystal cells at the top end of its screen with respect to the timing of application of grayscale voltage to liquid crystal cells in the center of the screen and the timing of application of grayscale voltage to liquid crystal cells at the bottom end of the screen with respect to the timing of application of grayscale voltage to the liquid crystal cells in the center of the screen are made approximately coincident with each other or are deviated from each other by approximately one scanning-line selection period, and a liquid crystal panel is illuminated by a backlight which is intermittently lit in synchronism with vertical synchronizing signals.
1 . A liquid crystal display device comprising:
a liquid crystal display panel;
a back light having a plurality of a back light lamps and a diffusing sheet;
a plurality of drain signal lines and a plurality of scanning signal lines formed in the liquid crystal display panel;
wherein a time period to complete a selection of all of the plurality of scanning signal line is shorter than a half of a time period of one frame period, each of the scanning signal line is selected once in said one frame period and continues maintaining a writing state until a scanning-line selection of a subsequent frame period,
two of the scanning line are simultaneously selected in said one frame period,
the back light lamps are divided into three region such as the upper part of a screen, a middle part of the screen, and lower part of the screen,
the upper part and the lower part of the back light lamps turns on in said one frame period before selection of all the scanning signal lines are selected in said one frame period, and
the middle part of the back light lamps turns on in said one frame period after selection of all the scanning signal lines are selected in said one frame period.
2 . A liquid crystal display device according to claim 1 , wherein a back light lighting period is shorter than the one frame period.
3 . A liquid crystal display device according to claim 1 , wherein the selection of two of the scanning signal lines is performed from the top and bottom ends of the screen to a center of the screen in one frame period.
4 . A liquid crystal display device according to claim 1 , wherein the selection of two of the scanning signal line is performed from the center of a screen to the top and bottom ends of the screen in one frame period.
5 . A liquid crystal display device according to claim 1 , wherein the diffusion sheet has light-shading dots at the position which overlaps on the back light lamps.
6 . A liquid crystal display device according to claim 1 , wherein the back light lamps are a cold cathode fluorescence lamp.