The reason your phone keeps dimming even with auto-brightness off

If your iPhone or Android phone's screen keeps darkening when you don't want it to, there are several possible explanations.

If your iPhone or Android phone&#39;s screen keeps darkening when you don&#39;t want it to, there are several possible explanations.<p><img src="https://www.engadget.com/img/gallery/the-reason-your-phone-keeps-dimming-even-with-auto-brightness-off/intro-1793800884.jpg" /></p>