Patent ID: 9607561
Date: 2017-03-28
CPC Classifications: G09G

Claim:
1. A liquid crystal display device for displaying an image by applying an alternating-current voltage to a liquid crystal, based on an input image signal, the liquid crystal display device comprising: a display unit including a plurality of video signal lines for transmitting a plurality of video signals based on the input image signal, respectively, a plurality of scanning signal lines intersecting with the plurality of video signal lines, a plurality of switching elements arranged in a matrix form in correspondence with intersections between the plurality of video signal lines and the plurality of scanning signal lines, a plurality of pixel electrodes connected to the plurality of switching elements, respectively, and a common electrode disposed to face the plurality of pixel electrodes via the liquid crystal, the display unit configured to display the image based on the input image signal; an image determination part configured to determine whether or not the image based on the input image signal is an image analogous to a first pattern which is a polarity reversal pattern in a first reversal driving scheme specified in advance for applying the alternating-current voltage to the liquid crystal, and to output a determination result; a reversal driving scheme decision part configured to decide a reversal driving scheme for applying the alternating-current voltage to the liquid crystal, based on the determination result; and a liquid crystal drive unit configured to drive the liquid crystal by applying a predetermined voltage to the common electrode, applying the plurality of video signals to the corresponding video signal lines, respectively, and selectively driving the plurality of scanning signal lines, wherein with regard to each unit area where the determination by the image determination part is made, the reversal driving scheme decision part decides the reversal driving scheme for applying the alternating-current voltage to the liquid crystal in the unit area, as a second reversal driving scheme by which a second pattern which is a polarity reversal pattern different from the first pattern appears, when the determination result indicates that the image based on the input image signal is the image analogous to the first pattern, the liquid crystal drive unit drives the liquid crystal by using the reversal driving scheme decided by the reversal driving scheme decision part, by controlling the polarities of the plurality of video signals, the first reversal driving scheme is column-reversal driving of reversing the polarity of the voltage applied to the liquid crystal every video signal line, the second reversal driving scheme is dot-reversal driving of reversing the polarity of the voltage applied to the liquid crystal every scanning signal line and every video signal line, the image determination part determines whether or not the image based on the input image signal is the image analogous to the first pattern every area corresponding to two scanning signal lines, the reversal driving scheme decision part decides the reversal driving scheme for applying the alternating-current voltage to the liquid crystal every area corresponding to two scanning signal lines, the display unit includes a plurality of pixels each formed of three sub-pixels of red, green, and blue arranged in this order in an extending direction of the plurality of scanning signal lines, and the image determination part determines that the image based on the input image signal is the image analogous to the first pattern when both the following expressions (7) and (8) are satisfied based on calculation results of the following expressions (1) to (3) and calculation results of the following expressions (4) to (6), with a 2-by-2 pixel group defined as one image analyzing filter: in which R