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Why do TFT LCD screens produce bright spots, black spots, and color dots?


For LCD liquid crystal screens, for example, a TFT liquid crystal display with a resolution of 1024x768 has 786432 light point groups (one light point group is composed of three light points, which respectively control the brightness of RGB filters). The light points in each of the above light point groups are independently responsible for color display and light brightness. The bright spot phenomenon occurs on all LCD displays, including the color LCD display on digital cameras. The reason is that each light spot on the LCD screen has an independent transistor to control the strength of its current. If the transistor at that spot breaks down, it will cause the light spot to be permanently lit or not lit, and the color when lit will also fix a certain color, which is the highlight of the LCD.

How did the highlights come about? In a color LCD panel, each pixel is composed of three LCD cells, with red, green, or blue filters in front of each cell. In this way, the light from different cells can display different colors on the screen.

According to the analysis by the LCD supplier, the phenomenon of bright spots on the LCD is due to the damage of the optical rotation function of the LCD display body, resulting in the inability of the LCD body to perform normal optical rotation and polarization operations under the power and signal supply conditions. This causes the LCD to display a non black bright spot in a black backlight state, which is called a bright spot. If on the contrary, it displays a constant dark spot in a full white backlight state, which is called a dark spot.

Why does the optical rotation function of the LCD display body cause damage? No matter at which stage it occurs, the reasons are all-encompassing and cannot be covered by a single reason. These reasons may include the premature death of the liquid crystal body and the abnormal display of the liquid crystal caused by foreign objects falling into the interior of the LCD.