There are many reasons for this:
* ***Software Glitches***: Sometimes, updates or apps can cause temporary issues with your screen.
* ***Battery Saver Mode***: When your battery is low, your device might automatically dim or turn off the screen to save power.
* ***Overheating***: If your device gets too hot, it might shut down or darken the screen to cool down.
* ***Hardware Problems***: Rarely, there could be a problem with your device's screen or internal components.
If none of the other solutions work, it might be worth getting it fixed at service center.