Design of a wide field-of-view, compact head-mounted display based on free-form prisms tiling

With the advent of high brightness microdisplay, augmented reality head mounted display (AR-HMD) has rapidly developed and applied. Various optical schemes emerge one after another. However, it is still a huge challenge to realize large field of view (FOV), high resolution and keep the compact form of head mounted display. We propose a novel free-form prism tiling optical system, which can simultaneously realize large field of view, high resolution and compact optical see-through augmented reality HMD. It can overcome the FOV/resolution invariant and solves the problem that the optical axes of the display channels don't coincide with the visual axis of the human eye. The optical system consists of two microdisplays, two free-form prisms and a compensation lens which are attached together. The prisms are partially overlapped to provide the same field of view and reduce the seam at the transition region of adjacent FOV. The optical see-through system we designed achieves large FOV of 52.8°×52.8° (70° diagonally) and resolution of 33.7 pixels/degree, and has good optical performance. We emulated the system with distortion and illuminance pre-conditioning and discussed the remaining problems and future work.