How do LCD screens work? In simple terms, the basic principle that can be displayed on the screen is to fill the liquid crystal material between two parallel plates, and change the arrangement of the molecules inside the liquid crystal material by the voltage to achieve the purpose of shading and light transmission to display different shades and vivid image, and as long as a three-color filter layer is added between the two plates, a color image can be displayed.

Recognize its structure and principle, understand its technology and process characteristics, it can be targeted at the time of 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 major axes of these rod-shaped molecules are approximately parallel.

The first feature of the LCD screen is that the liquid crystal must be poured between two thin-slotted planes to work properly. The grooves in the two planes are perpendicular to each other (90°), that is, if the molecules in one plane are aligned in the north-south direction, the molecules in the other plane are arranged in the east-west direction, and the molecules located between the two planes are forced into a 90° twisted state. Because the light travels in the direction of the molecules, the light is also twisted 90° when passing through the liquid crystal. However, when a voltage is applied to the liquid crystal, the molecules are re-arranged vertically so that the light can be emitted directly without any twisting.

The second feature of the LCD screen is that it relies on polarization filters and the light itself, natural light is randomly diverging in all directions, and the polarizing filter is actually a series of increasingly thin parallel lines. These lines form a net that blocks all light that is not parallel to these lines. The lines of the polarizing filter are exactly perpendicular to the first, so they can completely block those rays that have been polarized. Only if the lines of the two filters are completely parallel, or the light itself has been twisted to match the second polarizing filter, the light can penetrate. On the one hand, the LCD is composed of such two mutually perpendicular polarization filters, so under normal circumstances it should block all light that tries to penetrate. However, because the two filters are filled with twisted liquid crystals, after passing through the first filter, light is twisted to 90° by the liquid crystal molecules, and finally pass through the second filter. On the other hand, if a voltage is applied to the liquid crystals, the molecules will be rearranged and completely parallel, so that the light is no longer twisted, so it is blocked by the second filter. In short, light is blocked by power-up, 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 light is emitted when it is powered on and is blocked when it is not powered. However, since the LCD screen is almost always lit, only the “power-on-light blocking” scheme can achieve the goal of the most power saving.