If your iPhone screen turns off while you're reading or watching something else on it, there's a way to stop this from happening in settings .
The reason why your iPhone keeps going dark and turning off is due to a feature called “Auto-Lock“, which automatically puts the device into sleep/lock mode after a certain period of time. Before it enters Auto-Lock mode, the screen reduces the brightness to half. To fix this, you need to turn off “Auto-Lock”.
First, open the “ Settings ” app by tapping the “gear” icon.
In “Settings”, tap “Display & Brightness”.
Then select “Display & Brightness”, scroll down and tap “Auto-Lock”.
Under “Auto-Lock,” you’ll see a list of time options. These determine how long your iPhone’s screen will stay on before it turns off and goes into lock mode.
In this case, because you want to disable it completely, you will select “Never”.
After that, exit “Settings.” Whenever you turn on your iPhone, its screen will stay on and won’t go into lock mode until you press the button.
If you continue to have issues with screen brightness even with Auto-Lock turned off, it may be because Auto-Brightness is turned on. Auto-Brightness can be turned off in the Accessibility options in the Settings app.
However, there are some disadvantages to disabling “Auto-Lock”, the first of which is that the battery drains much faster. Furthermore, when phone doesn’t automatically lock, anyone could use it. Therefore, it may be better to turn “Auto-Lock” back on when you’re done.
