High-efficiency folded optics for near-eye displays.

Pancake lens structure offers a promising solution to compact formfactor for near-eye displays. However, utilizing a half mirror to triple the optical path length causes a dramatic optical loss. The theoretical maximum optical efficiency is only 25%. To balance the tradeoff between compact formfactor and optical efficiency, here we propose a new folded optical structure with a doubled efficiency and doubled optical path length, using two polarizationselective cholesteric liquid crystal reflectors. Simulation results agree with the experiment reasonably well. Two display configurations are established to evaluate the imaging performances of the proposed pancake lens structure. [ABSTRACT FROM AUTHOR]