When acting on the mobile phone, the ambient light sensor can adjust the backlight and display brightness by detecting the ambient light. For example, in the dark environment, too bright screen can harm your eyes. At this time, turn on the backlight, the brightness of the screen will change follow the ambient light to protect the eyes; Proximity light sensors can detect the distance between object and the chip to judge whether it is approaching or away. For example, when answering a phone call, the backlight can be turned off when the phone is held to the user's ear, and turned on when it is far away.

If the screen is working for a long time, the battery life of the mobile phone will be affected. Changing the screen brightness according to different operating environments can effectively reduce power consumption and prolong the battery life.