Holographic curved waveguide combiner for AR/HUD with 2D pupil expansion

Augmented Reality (AR) and Head-up Display (HUD) applications are nowadays taking advantage of the pupil replication that it is possible to achieve with waveguide combiner to increase the eye box without sacrificing the field of view. However, most of the waveguide combiners are limited with flat geometry to avoid unwanted optical power. Flat waveguide ensures that no aberration is imparted to the image when the light propagates inside the medium. Yet, the aesthetic appeal of a flat combiner is not ideal since neither wearing glasses nor vehicle's windshield is flat. Here we propose a 1-D curved waveguide combiner that take the advantage of holographic optical elements (HOE) to minimize the aberration for 2-D pupil replication. Both ray tracing model and experimental demonstrator will be discussed.