US Patent 9116337 Increasing effective eyebox size of an HMD

An apparatus for a head mounted display includes light bending optics to deliver display light from an image source to a near-to-eye emission surface for emitting the display light to an eye of a user within an eyebox. An eye tracking camera system acquires an image of the eye for tracking movement of the eye. A controller is coupled to the eye tracking camera system to receive image data and to determine a location of the eye based on the image data. The controller is coupled to an eyebox actuator to dynamically adjust the lateral position of the eyebox based upon the location of the eye to extend an effective size of the eyebox from which the eye can view the display light.