Display Structure, Display Device, and Vehicle

A display structure (1000), comprising:

• a waveguide (1100);
• an in-coupling structure (1200) configured to couple a set of input beams (1020) into the waveguide (1100) as a set of in-coupled beams (1021) associated with a set of in-coupled k-vectors (3021) defining a first domain (2310) in k-space in an annular guided propagation domain (2001) associated with the waveguide (1100);
• a diffractive exit pupil expansion structure (1300) configured to receive the set of incoupled beams (1021) and to diffract the set of incoupled beams (1021) to form at least three sets of guided beams (1030) associated with at least three sets of k-vectors (3030) lying in at least three domains (2300) including the first domain (2310);
• and
• a diffractive retardation and out-coupling structure (1400) configured to receive from the exit pupil expansion structure (1300) a diffracted set of beams (1035) associated with a diffracted set of k-vectors (3035) lying in one of the at least three domains (2300), the diffractive retardation and out-coupling structure (1400) comprising an out-coupling grating (1420) configured to couple light out of the waveguide (1100) as a set of output beams (1044);
• wherein the retardation and out-coupling structure (1400) is configured to diffract the diffracted set of beams (1035) to form at least one re-turning set of beams (1040) guided towards the exit pupil expansion structure (1300) and associated with at least one returning set of k-vectors (3040), each of the at least one returning set of k-vectors (3040) lying in any other of the at least three domains (2300).