Here is the useful guide on how to prevent iOS 10 iPhone screen from turning off automatically. Typically we use Auto-Lock feature to conserve the battery, as well as adding some additional security if we have set up a password on device. But there are various situations when you don’t want your iPhone to lock automatically, and there’s a setting in iOS that can prevent it from happening.
For example, if you read a lot of books or websites on your device and hate when your display’s back light always goes dim on you while you’re in the middle of trying to read, then turning the Auto-Lock feature off will help to avoid the problem.
How To Prevent iPhone Screen From Turning Off Automatically
If you’ve decided to prevent iOS 10 iPhone screen from turning off automatically, you can do so by following easy steps below:
1) On your iOS 10 device open the Settings app from the Home screen.
2) Launch the Display & Brightness preferences pane.
3) Click on the Auto-Lock cell.
4) Choose Never from the list of options.
When Never is chosen from the list, your device won’t lock itself automatically after any period of time; it doesn’t matter what you’re doing, whether you’re in an app, staring at your Home screen, or streaming via AirPlay.
However, that your Lock screen will still dim after a few seconds of inactivity as usual, no matter what Auto-Lock setting you choose. So keep that in mind.
Those users who have jailbroken iOS 10 device can also use CustomLockscreenDuration tweak that lets choose how long of a delay there is before your Lock screen falls asleep. This tweak is available as a free download package from Cydia's Big Repository and it only affects the Lock screen.