Apochromatic Pancharatnam Berry Phase (PBP) liquid crystal structures for head-mounted displays

A head-mounted display (HMD), comprising:

• an electronic display configured to emit image light that is inclusive of a set of color channels;
• an optical assembly configured to be a substantially apochromatic lens for the set of color channels, the structure comprising:
• a first optical element configured to:
• receive light of a first color channel of a set of color channels and light of a second color channel of the set of color channels, the first color channel corresponding to a first wavelength range and the second color channel corresponding to a second wavelength range, and
• perform a half wave phase shift for light of the first color channel and a full wave phase shift for at least light of the second color channel;
• a liquid crystal lens configured to receive the light of the first color channel and the light of the second color channel transmitted through the first optical element;
• and
• a second optical element configured to:
• receive the light in the first color channel and the light in the second color channel transmitted through the liquid crystal lens, and
• perform a half wave phase shift for light of the second color channel, and a full wave phase shift for a least light of the first color channel;
• wherein the structure is configured such that the light in the first color channel and the light in the second color channel transmitted through the structure have a substantially common focus point.