In simple terms, the basic principle of the screen display is to fill the liquid crystal material between the two parallel plates, and change the arrangement of the molecules inside the liquid crystal material by voltage to achieve the purpose of shading and light transmission to display different shades. A patchwork image is obtained, and a color image can be displayed by adding a ternary color filter layer between the two panels.
Knowing its structure and principle, understanding its technical and technological characteristics, can be targeted in the purchase, more scientific and reasonable in application and maintenance. Liquid crystal is an organic compound composed of long rod-shaped molecules. In the natural state, the long axes of these rod-shaped molecules are substantially parallel. The first feature of the LCD is that the liquid crystal must be poured between two planes with fine grooves to work properly. The grooves on the two planes are perpendicular to each other (90 degrees intersect), that is, if the molecules in one plane are arranged in the north-south direction, the molecules on the other plane are arranged in the east-west direction, and the molecules located between the two planes are Forced into a state of 90 degree twist. Since the light propagates in the direction in which the molecules are arranged, the light is also twisted by 90 degrees as it passes through the liquid crystal. But when a voltage is applied to the liquid crystal, the molecules are vertically aligned so that the light can be directed out without any twisting. The second characteristic of the LCD is that it relies on the polarizing filter and the light itself. Natural light is randomly diverging in all directions. The polarizing filter is actually a series of increasingly thin parallel lines. These lines form a net that blocks all rays that are not parallel to these lines, and the lines of the polarizing filters are exactly perpendicular to the first one, so that the already polarized light is completely blocked. Only when the lines of the two filters are completely parallel, or the light itself has been twisted to match the second polarized filter, the light is penetrated. The LCD is composed of such two mutually perpendicular polarizing filters, so that all attempts to penetrate light should be blocked under normal conditions. However, since the two filters are filled with twisted liquid crystals, after the light passes through the first filter, it is twisted by the liquid crystal molecules by 90 degrees, and finally passes through the second filter. On the other hand, if a voltage is applied to the liquid crystal, the molecules are rearranged and completely parallel, so that the light is no longer twisted, so it is just blocked by the second filter. In short, power is applied to block light, and light is emitted without power. Of course, it is also possible to change the arrangement of the liquid crystals in the LCD so that the light is emitted when it is powered on, and is blocked when it is not powered. However, since the liquid crystal screen is almost always on, only the "power-on light blocking" scheme can achieve the most power-saving purpose.
