Review of fast switchable liquid crystal lenses for virtual reality applications

Virtual Reality (VR) devices present challenges in terms of vergence-accommodation conflict that lead to visual fatigue for the user over time. Fast switchable liquid crystal (LC) lenses which access multiple focal planes can help to overcome this challenge. The response time for Nematic liquid crystals (NLC) is in the millisecond range, while that of ferroelectric liquid crystals (FLC) in the microsecond order. In this paper we look at recent advances in fast switchable liquid crystal lenses using NLC, FLC or both, compare their design and properties with competing technologies. A discussion on the limitations of each design and technology have also been included.