When I unlock my phone, my Nexus 4's screen light go from light to dim light instantly, why?

[AnxiousTuber]

When I unlock my phone, my nexus 4's screen light go from light to dim light instantly

Would this problem be because of my LCD or my motherboard or what is causing it?

 

[B. Diddy]

Re: When I unlock my phone, my nexus 4's screen light go from light to dim light instantly

Welcome to Android Central! Is Auto Brightness on or off?

 

[Gvizdon]

Re: When I unlock my phone, my nexus 4's screen light go from light to dim light instantly

Protection film or dirt on light sensor may cause it. Try to clean it, or remove film. It helps me