There is no manufacturer's reason: the bright spot/bad spot, also called the bright spot on the LCD screen, is a kind of physical damage to the LCD screen, mainly due to the slight deformation of the internal reflector at the bright spot caused by external pressure or heating. Reasons during use: Some LCDs have bright spots/bad spots during use. Some precautions in normal use: 1 Do not install multiple systems at the same time; After installing multiple systems, the LCD screen will be damaged to some extent during the switching process. 2 Keep the voltage and power normal.