If the screen of your iPhone is Frequently switching OFF, you can find below the steps to Stop iPhone Screen from Turning OFF automatically.
Stop iPhone Screen from Automatically Switching OFF
The default setting on iPhone is to automatically switch OFF the screen, when it is unlocked and remains unused for a period of i minute.
While this setting helps in conserving battery life, you may sometimes find the need to prevent the screen of your iPhone from automatically switching OFF.
Another option is to increase the Auto-Lock period on your device from its default 1 minute setting to a longer duration.
1. Prevent iPhone Screen from Automatically Switching OFF
All that is required to prevent the disaply or the screen of your iPhone from automatically switching OFF is to go to Settings > Display & Brightness > Auto-Lock and select the Never option.
After this, you will no longer find the screen of your iPhone automatically switching OFF. The screen will remain switched ON, until it is mabually switched OFF by pressing the Power button.
2. Prevent iPhone Screen from Switching OFF Frequently
The other option is to increase the Auto-Lock period, which prevents iPhone from frequently switching OFF its display.
Go to Settings > Display & Brightness > Auto-Lock > On the next screen, select 2 minutes or any other duration that suites your own requirements.
After this you will find your device going into sleep mode after 2 minutes of inactivity. If this is not enough, you can increase the Auto-Lock period to 3, 4 or 5 minutes.