Field-of-view expansion via diffractive image steering and prism array

Abstract

Enabling all-day-wearable augmented reality (AR) displays require compact engineering solutions that still satisfy requirements like wide field-of-view (FOV) and high resolution. By using a Digital Micromirror Device (DMD) and a pulsed laser in synchronization we are able to perform diffractive image steering which decouples the FOV of the projected image from the display size while not sacrificing image resolution. This approach reduces, by several factors, the lateral extent of the display panel while retaining image resolution. The diffractive-steering-enabled FOV expansion by the DMD, paired with a prism array placed at the exit pupil of the projection lens, maintains a small form factor by re-distributing a part of the volume from the projector engine to the image transfer optics. Together with diffractive image steering and the prism array we demonstrate a 5x increase in field-of-view. This approach decreases the requirement on the number of pixels to maintain high resolution across a wide FOV, which makes it suitable for eventually installing it in small form factor head mounted displays.