With VR headsets, the problem isn’t putting two displays in front of the user’s eyes. The problem is determining where the user is looking quickly and accurately. Few days ago I saw an interesting Introduction To Valve’s Tracking Hardware article that tells thew basics of ‘Lighthouse’ tracking unit operation: By scanning these IR lasers across the VR headset the position and direction can be pretty easily determined.
For more details and other application ideas, read also Valve’s “Lighthouse” Tracking System May Be Big News for Robotics article. This solution is elegant for a few reasons.