Why Is The Bottom Half Of My iPhone 5 Dark?

I took out my iPhone 5 and it is dark only on the bottom half of the screen. I took it apart and reconnected the cables and even held the power and home button down until the Apple Logo appeared and nothing has worked yet. Please help?! It's annoying. Why Is The Bottom Half Of My iPhone 5 Dark

Check if your iPhone is old, change the Brightness, warning, if you Change the brightness high, you lose battery Easily.

It's called, iPhones are garbage and you should get a nice android. People say apple makes the best products because they heard someone else say they are the best. Well guess what, they aren't.