Polychromatic see-through near-eye display design with two waveguides and a large field-of-view

Abstract

We propose a new kind of waveguide near eye display (WGNED) with new in-coupling and propagation subsystems to vertically enlarge the field-of-view (FOV). Two waveguides are stacked up with a 0.1 mm air gap so that light can propagate inside the two waveguides independently. The light from a micro-display is coupled into the first waveguide by the in-coupling subsystem. Light propagates inside the first waveguide until reaching a cylindrical mirror at its edge. In the area near the mirror, the two waveguides are combined together. Then, the light is reflected by a cylindrical mirror and coupled to the second waveguide. The out-coupling from the second waveguide is realized either by a holographic optical element or cascaded micro mirrors. A cylindrical mirror allows most of the light coming out to reach the viewer’s eye. A two-lens subsystem with freeform surfaces is used as an in-coupling element to correct the aberrations. An advantage of our design is that the chief ray of each object field converges to the eye with an enlarged FOV in the vertical direction. The system has been simulated in mixed sequential and non-sequential mode in Zemax®. It can achieve a 20°×55° total FOV which is, to our knowledge, larger than the published WGNED designs.