Hello, you can use apps that use your phone's screen as flashlight.
Such as this one
https://play.google.com/store/apps/details?id=com.workpail.flashlight
But probably all those kind of apps needs some permission to keep phone awake.
If you don't want to give any permission and can't find an app
You can also use an all white background image
If your brightness levels are high or your auto brightness works fine it would provide enough luminance.
You can also download lit light bulb images from the Internet or you can just take a picture of a bright object and use that image as light.
Hope this helps.
