US Patent 10901205 Focus adjusting liquid crystal lenses in a head-mounted display

A head-mounted display (HMD) includes an electronic display configured to emit an image. The HMD also includes an eye tracking module configured to determine a position of an eye of a user of the HMD, and a varifocal block. The varifocal block includes a stacked liquid crystal (LC) structure that has a tunable optical power. The varifocal block is configured to present the image to the user of the HMD at an adjustable focal distance that is determined by the tunable optical power and is based in part on the determined position of the eye.