I just noticed this for the past 2 days now.
1/4 of the screen is black then slowly flickrs back to life, like nothing happened. It does not persist while Im using the tablet on apps and browsers. It's just during the unlocking and turning on and off. It's like that part of the screen gets electricity later than the rest. I'm really worried. Is it hardware problems?
Sorry for the photo. Used my lousy webcam. The part in the box is where it goes black. It's inverted, sorry for that.
It's the iPad 4 32gb wifi only. iOS 6.1.3.