Liquid crystal for vision correction

A head mounted display (HMD) system, comprising:

• a display device, a pixel array in the display device being configured to generate light beams;
• and
• an optical system including:
• an electrically tunable lens system including one or more liquid crystal (LC) lenses that are refractive optical elements, the one or more LC lenses having a first chromatic aberration,
• a Pancharatnam-Berry (PB) phase lens that is a diffractive optical element, the PB phase lens having a second chromatic aberration that is complementary to the first chromatic aberration, and
• a LC spatial light modulator (SLM) disposed between the electrically tunable lens system and the PB phase lens, wherein
• a chromatic aberration of the optical system is less than the first chromatic aberration,
• when a light beam from the electrically tunable lens system and incident on the LC SLM is linearly polarized, the LC SLM is configured to convert the linearly polarized light beam into a first circularly polarized light beam that is output from the LC SLM, and the PB phase lens is configured to convert the first circularly polarized light beam on the PB phase lens into a second circularly polarized light beam that is output from the PB phase lens, and
• the first circularly polarized light beam and the second circularly polarized light beam are (i) left circularly polarized and right circularly polarized, respectively, or (ii) right circularly polarized and left circularly polarized, respectively.

A method of tuning an optical system, comprising:

• obtaining vision correction information for at least one of nearsightedness or farsightedness;
• determining a respective optical power of each liquid crystal (LC) lens in a stack of LC lenses in an electrically tunable lens system and an optical power of a Pancharatnam-Berry (PB) phase lens based on the vision correction information;
• determining respective voltages to be applied to the stack of LC lenses based on the respective optical powers of the LC lenses;
• determining a polarization state of light incident on the PB phase lens based on the optical power of the PB phase lens;
• applying the determined respective voltages to the stack of LC lenses and controlling the polarization state of light incident on the PB phase lens to correct for the at least one of the nearsightedness or the farsightedness, wherein
• the optical system includes the electrically tunable lens system including the stack of LC lenses that has a first chromatic aberration, the PB phase lens that has a second chromatic aberration complementary to the first chromatic aberration, and a LC spatial light modulator (SLM) disposed between the electrically tunable lens system and the PB phase lens,
• a chromatic aberration of the optical system is less than the first chromatic aberration,
• when a light beam from the electrically tunable lens system and incident on the LC SLM is linearly polarized, the LC SLM is configured to convert the linearly polarized light beam into a first circularly polarized light beam that is output from the LC SLM, and the PB phase lens is configured to convert the first circularly polarized light beam on the PB phase lens into a second circularly polarized light beam that is output from the PB phase lens, the polarization state of light incident on the PB phase lens being the polarization state of the first circularly polarized light beam, and
• the first circularly polarized light beam and the second circularly polarized light beam are (i) left circularly polarized and right circularly polarized, respectively, or (ii) right circularly polarized and left circularly polarized, respectively.