Liquid crystal display device and method for driving same

A liquid crystal display device that displays an image represented by inputted image data on a display unit by applying a data voltage corresponding to the image data to a liquid crystal layer of the display unit, the liquid crystal display device comprising:

• a drive unit configured to apply the data voltage to the liquid crystal layer;
• and
• a display control unit configured to manage a polarity bias of the data voltage in a predetermined period unit, and to control the drive unit in a direction in which the polarity bias of the data voltage is eliminated in a frame period for updating the image displayed on the display unit, wherein
• the display unit includes a plurality of pixel formation portions that hold the data voltage;
• in order to eliminate the polarity bias in the frame period for updating the image, the display control unit specifies a direction in which a polarity bias value representing the polarity bias is changed, and controls the drive unit to apply the data voltage to each of the plurality of pixel formation portions, the data voltage having the polarity bias value changed in the specified direction for each of the frame period for updating the image and of frame periods subsequent to the frame period,
• the display control unit includes:
• a polarity bias management circuit that obtains and manages the polarity bias value in the predetermined period unit;
• a polarity reverse control circuit that generates a polarity signal that controls the polarity bias value in a direction in which the polarity bias value approaches “0” in a case where the polarity bias value outputted from the polarity bias management circuit is not “0” in the frame period for updating the image, and controls the polarity bias value in a direction in which the polarity bias value is reversed in a case where the polarity bias value is “0” in the frame period;
• a timing control circuit that generates, at predetermined timing, a refresh signal indicating that the frame period is the frame period for updating the image, and to give the generated refresh signal to the polarity bias management circuit and the polarity reverse control circuit;
• and
• an NREF counter that counts a number of pause frame periods,
• the polarity bias management circuit increases or decreases the polarity bias value by “1” in the direction specified by the polarity signal given from the polarity reverse control circuit,
• when an off-sequence signal that is an alternating current voltage having a predetermined frequency and erase data for erasing the data voltage written into the pixel formation portions are given to the display control unit in a case of stopping an operation of the liquid crystal display device,
• the timing control circuit generates the refresh signal based on the off-sequence signal and outputs the generated refresh signal to the polarity bias management circuit and the polarity reverse control circuit,
• the polarity bias management circuit increases or decreases the polarity bias value by “1” in the direction specified by the polarity signal every time a polarity of the off-sequence signal is changed, and
• the erase data is given to the drive unit.