LCD knowledge principle

LCD knowledge principle

Liquid crystal is a regularly arranged organic compound. It is a substance between solid and liquid. At present, the molecular arrangement is generally used in the manufacture of nematic columnar liquid crystals that are most suitable for liquid crystal displays. The liquid crystal itself cannot construct light. It mainly displays images by changing the arrangement of liquid crystal molecules due to the electric field generated by the change of voltage.

　　The LCD panel is mainly composed of two pieces of soda-free glass sandwiched by a polarizer, a liquid crystal layer and a color filter. Polarizers and color filters determine how much light can pass through and what color light is generated. Liquid crystal is poured between two well-made planes to form a liquid crystal layer. There are many grooves on these two planes. The grooves on a single plane are parallel, but the grooves on the two parallel planes are parallel. Are perpendicular to each other. Simply put, if the grooves on the back plane are arranged longitudinally, then the front plane is arranged horizontally. The arrangement of liquid crystal molecules between the two planes will form a gradual twisting state of 90 degrees in the Z axis. The light from the backlight source, that is, the lamp tube, passes through the backlight plate and reflective film on the back of the LCD screen to produce uniform backlight light. The light passes through the back layer and is twisted in the Z-axis by the liquid crystal, so that it can pass through the front layer plane. If a voltage is applied to the liquid crystal layer, an electric field will be generated, and the liquid crystal molecules will be rearranged, and the light cannot be twisted and thus cannot pass through the plane of the front layer, thereby blocking the light.

Brightness: Human eyes can distinguish about 250 brightness levels. The brightness of liquid crystal displays is generally higher than that of traditional CRT displays. The brightness of liquid crystal displays is generally measured in cd/m2 (lumens per square meter). The higher the brightness, the resistance of the display to the surrounding environment. The stronger the interference ability, the brighter the display effect. LCD response time refers to the response speed of the LCD display to the input signal, that is, the response time of the liquid crystal from dark to bright or from bright to dark (the response time of CRT displays is generally less than 1ns (nanoseconds), so it can be ignored Excluding). It is divided into two parts: Rising (rising time) and Falling (falling time), and the response time is the sum of the two.