iPhone 5s Screen contrast gets washed out after 1-2 seconds

Hi.

My Iphone 5s screen has an interesting issue. When ever I turn on the screen. It is ok for 1 second then the contrast gets washed out. You can still see everything, but in a kind of haze. If I press the power button to lock it then press it again it will work again perfectly for a second then get washed out again. Is it a cable connection issue? Or it needs to be replaced.?

Thanks