Light guide device and near-eye display

A near-eye display, comprising:

• an image light source, adapted to emit a light beam;
• and
• a light guide device, disposed on a transmission path of the light beam, adapted to guide the light beam, and the light guide device comprising:
• a light guide plate;
• a diffraction grating, disposed on a first surface of the light guide plate, wherein when the light beam is incident on the diffraction grating, the diffraction grating is adapted to generate a plurality of diffraction beams, the plurality of diffraction beams comprise a major diffraction beam, and the major diffraction beam is transmitted in the light guide plate;
• and
• a phase retardation element, disposed on a transmission path of the major diffraction beam, wherein the major diffraction beam has a first polarization state before being incident on the phase retardation element, and the major diffraction beam has a second polarization state when leaving the phase retardation element, wherein the first polarization state is different from the second polarization state.