What is the reason that there are black spots on the screen of mobile phone?

Black spots appear on the phone screen for the following reasons:

1, pixel fault: the screen of mobile phone is composed of many tiny pixels, and the damage or death of a pixel will be displayed as a black dot on the screen.

2.LCD layer problem: the LCD layer on the screen of the mobile phone is damaged or aging, which will also lead to black spots.

3. Dust or stains: Black spots on the screen are dust, stains or other impurities, which can be solved by cleaning the screen.