In LCD technology, liquid crystal is poured between two planes with narrow grooves. The grooves on these two planes are perpendicular to each other (intersecting at 90 degrees). That is to say, if the molecules on one plane are arranged from north to south, the molecules on the other plane are arranged from east to west, and the molecules between the two planes are forced into a 90-degree twisted state. Since the light travels in the direction of the molecular arrangement, the light is also twisted 90 degrees when passing through the liquid crystal, but when a voltage is applied to the liquid crystal, the molecules will be rearranged vertically so that the light can be emitted directly without any twist.

The LCD relies on polarizing filters (chips) and the light itself. Natural light diverges randomly in all directions. A polarizing filter is actually a series of increasingly thin parallel lines. These lines form a net, blocking all light rays that are not parallel to these lines. The line of the polarizing filter is exactly perpendicular to the first one, so it can completely block the polarized light. Only when the lines of the two filters are completely parallel, or the light itself has been twisted to match the second polarization filter, can the light penetrate.

The LCD is composed of two polarizing filters that are perpendicular to each other, so under normal circumstances, all light trying to penetrate should be blocked. However, since the two filters are filled with twisted liquid crystals, after the light passes through the first filter, it will be twisted 90 degrees by the liquid crystal molecules and finally pass out of the second filter. On the other hand, if a voltage is applied to the liquid crystal, the molecules will be rearranged and completely parallel, so that the light is no longer twisted, so it is just blocked by the second filter. In short, the light is blocked by power, and the light is emitted without power.

However, the arrangement of liquid crystals in the LCD can be changed so that the light is emitted when powered on and not blocked when not powered. However, since the computer screen is almost always on, only the "power off to block light" solution can achieve the most power-saving purpose.

From the standpoint of the liquid crystal display, whether it is a notebook computer or a desktop system, the LCD screen used is a layered structure composed of different parts. The LCD consists of two glass plates, about 1mm in length, and is separated by a 5um containing liquid crystal (LC) material at even intervals. Because the liquid crystal material itself does not emit light, there are lamps as light sources on both sides of the display, and there is a backlight plate (or uniform light plate) and a reflective film on the back of the liquid crystal display. The backlight plate is composed of fluorescent substances Can emit light, its role is to provide a uniform background light source.

After passing through the first polarization filter layer, the light emitted from the backlight board enters the liquid crystal layer containing thousands of crystal droplets. The crystal droplets in the liquid crystal layer are contained in a fine cell structure, and one or more cells constitute a pixel on the screen. There is a transparent electrode between the glass plate and the liquid crystal material. The electrode is divided into rows and columns. At the intersection of rows and columns, the optical rotation state of the liquid crystal is changed by changing the voltage. The function of the liquid crystal material is similar to a small light. valve. Around the liquid crystal material are the control circuit part and the drive circuit part. When the electrodes in the LCD generate an electric field, the liquid crystal molecules are twisted, so that the light passing through them is refracted regularly, and then filtered by the second filter layer is displayed on the screen.