Focus adjusting pancharatnam berry phase liquid crystal lenses in a head-mounted display

A head-mounted display (HMD) comprising:

• a varifocal block that receives content from an electronic display, and presents the content over a plurality of image planes that are associated with different optical powers of the varifocal block, the varifocal block comprising:
• a switchable half waveplate (SHWP) that outputs circularly polarized light, and a handedness of the circularly polarized light is controlled by the SHWP being in an active state or a non-active state,
• a plurality of liquid crystal (LC) lenses and each LC lens of the plurality of LC lenses is arranged in optical series with each other and the SHWP and each LC lens of the plurality of LC lenses has a plurality of optical states, the plurality of optical states including an additive state that adds optical power to the LC lens and a subtractive state that removes optical power from the LC lens, and
• wherein the handedness of the circularly polarized light and the plurality of optical states of each of the plurality of the LC lenses together provide a range of adjustment of optical power for the varifocal block, and each value of optical power over the range of adjustment of optical power corresponds to a different image plane of the plurality of image planes.