Exponentially-wide étendue displays using a tilting cascade

A fundamental limitation of spatial light modulation (SLM) devices is that their etendue, defined as the product of the display's size and angular range, is bounded by the number of pixel units. Current SLMs are woefully inadequate in meeting the spatial and angular ranges of many real applications. In particular using these SLMs to generate realistic computer-controlled holographic displays would require scaling the number of display units by a few orders of magnitude. In this work, we suggest that rather than excessively increasing the pixel count, etendue can be expanded by augmenting the display units with tilting capabilities. Furthermore, we show that tiltable displays can be realized using a cascade of binary tilt layers, each capable of tilting the light towards one of two orientations. With proper design, the etendue-expansion factor scales exponentially with the number of display layers; hence, a very small number of such layers can effectively realize wide expansion factors. We implement a proof of concept display and demonstrate its applicability for displaying multi-view or holographic content with increased size and angular field-of-view.