Samsung calls it the 'flapping display'. They claim they can actually make it thinner, but it's a bit difficult.
To achieve this thickness, Samsung etched an OLED panel that uses a normal glass substrate. The drive circuit was formed by LTPS TFTs. Also, low-molecular organic EL materials were employed.
The panel was not sealed by a glass substrate but by membrane sealing technology using a sputtering method. That's why the 0.05mm thickness is almost the thickness of the drive circuit board.