Samsung Display developed a new high-resolution OLED display, specifically for VR applications. The 5.5" panel, on display at SID DisplayWeek, sported a 3840x2160 resolution - or 806 PPI. The panel offered a brightness of 350 nits and a color gamut of 97% adobe RGB.
This is the highest resolution mobile phone sized OLED ever demonstrated, and it exactly matches the highest resolution LCD - Sharp's 5.5" 806 PPI IGZO panel unveiled in 2015. Samsung's display probably uses some sort of PenTile architecture, though, so actual sub-pixel count is smaller.
In November 2014, Japan's SEL demonstrated a 2.8" 2560x1440 OLED panel - that reaches a PPI of 1058. The panel is based on SEL's CAAS-OS (C-Axis Aligned Crystalline Oxide Semiconductor) backplane, and has a WRGB structure.
VR is still a small market - but almost all VR headsets (including ones from Oculus, HTC, Sony and Samsung) use AMOLED displays due to the fast refresh rate which is considered mandatory for VR. The VR headset market is expected to grow very quickly in coming years.
One of the problems with current VR solutions is the limited resolution, and it is great to see Samsung achieve such a high resolution OLED. In July 2015 SDC announced it launched a new project to develop a 2250 PPI OLED display. Samsung is collaborating with 13 companies on this project, and they expect to show the first prototype by the 2018 Pyeongchang Winter Olympics.