Pressure between flat wires, conductive tapes and backside of LCD screen causes the problem. You should take apart your Raphael to see the back of LCD. There is a very thing black tape around the display. Check it for any kinf of damage. If there is no sign of penetration, make the same thin tape from any kind of office tape and place it over dark one. I hope this can help you.
Be a HTC Indiana Jones, take the danger and DIY!