Lightguide with Butterfly Eye-Pupil Expander based on Patent by Microsoft

In the process of the design of lightguide devices for augmented and mixed reality (AR&MR) applications, parameters like the provided Field of View (FOV) are of major interest. In order to push the limits of the maximum FOV achievable, various approaches have been investigated, such as systems that split the FOV during the propagation from incoupler to outcoupler. One very popular approach is the so-called “butterfly pupil expansion”, where two separate EPE grating regions are used for the positive and negative parts of the FOV, and which is also applied in Microsoft’s Hololens 2. In this document, we show the realization of such an EPE concept in VirtualLab Fusion, based on patent US9791703B1 by Microsoft.