After unlocking my phone, the screen is unresponsive for a few seconds. No touch is registered, and pressing on the home button is also ignored. After a few seconds have passed, I can use my phone as normal. I noticed this when I first used my iPhone, and have been experiencing it every time I unlock my phone after at least 5 minutes of standby. I have reset my iPhone by holding the power button and home button, and that was of no help.