Optical display system comprising a beam scanning unit and an exit pupil steering apparatus and an electronic device

An optical display system, comprising:

• a controllable optical image-generating display apparatus, adapted to generate circularly polarized image output;
• a beam scanning unit, adapted to reflect the circularly polarized image output to adjust a direction of the circularly polarized image output;
• an exit pupil steering apparatus, including a plurality of diffractive liquid crystal lenses, wherein each of the plurality of diffractive liquid crystal lenses is adapted to focus the circularly polarized image output of a first circular polarization state to a distinct focus point and let light with a second circular polarization state pass directly through;
• and
• an eye-tracking apparatus, adapted to detect position information of a viewer's eye pupil and provide the position information to the beam scanning unit,
• wherein the beam scanning unit is adapted to adjust the direction of the circularly polarized image output towards the exit pupil steering apparatus according to the position information, so that the circularly polarized image output is diffracted by one of the diffractive liquid crystal lenses to change the focus point.