Samsung has been awarded a new US patent (#8,330,347) that describes a foldable display made from two display panels that has smaller (but brighter) pixels at the "junction" between them. This allows the space between the panels to be smaller and create a foldable display. Such a design requires a panel where each pixel brightness can be controlled, so LCD is out of the question, and the patent mentions OLED, FED, Plasma and EL displays as possible candidates.
The original Korean patent was filed in 2006, so this isn't new. We hope that Samsung will be able to come-up with truly flexible OLED displays that will not need those smaller display at the junction because there won't actually be a junction - it'll be one large display.