Samsung has released a comparison of the 3D curve of its sAMOLED display for the Galaxy range. It started with Note 4 Edge, but in this image it show that the Galaxy S6 Edge as the first to compare.
Galaxy Note 5 doesn’t have the 3D curve display but having the back glass in 3D curve.
The S7 Edge is having the most curvy display along with the curved back glass.
The design is now symmetry for the Galaxy Note 7 where both front and back glass are curved more steeply in symmetrical shape.
Great job Samsung!