The driving voltage of the liquid crystal molecules cannot be fixed at a certain value, otherwise, over time, the liquid crystal molecules will undergo polarization and gradually lose their optical rotation characteristics. Therefore, in order to avoid the destruction of the characteristics of the liquid crystal molecules, the driving voltage of the liquid crystal molecules must be polarized, which requires the display voltage in the LCD liquid crystal screen to be divided into two polarities, one is positive polarity and the other is negative polarity. . When the voltage of the display electrode is higher than the voltage of the common electrode, it is called positive polarity; when the voltage of the display electrode is lower than the voltage of the common electrode, it is called negative polarity. Regardless of the positive polarity or the negative polarity, there will be a set of gray scales with the same brightness, so when the absolute value of the pressure difference between the upper and lower glass layers is fixed, the gray scales displayed are exactly the same. However, in these two cases, the turning of the liquid crystal molecules is completely opposite, which can avoid the above-mentioned characteristic damage caused when the turning of the liquid crystal molecules is always fixed in one direction. There are four common polarity conversion methods, namely frame-by-frame phase inversion, line-by-line phase inversion, column-by-column phase inversion, and point-by-point phase inversion.
