Optical device

An optical device comprising:

• a light guide plate configured to guide light within a plane parallel to an emission surface;
• and
• a plurality of light focusing portions to which the light guide plate guides directional light,
• wherein each of the light focusing portions is provided with an optical surface configured to create, from the directional light incident thereon, emission light in a direction substantially converging on a single convergence point or convergence line in a space, or to create emission light that substantially diverges from a single convergence point of convergence line in a space and exits from the emission surface,
• wherein the plurality of light focusing portions are provided near the emission surface of the light guide plate, and each of the plurality of light focusing portions is formed along a predetermined line within a plane parallel to the emission surface, and
• wherein the convergence point or convergence line is mutually different between the plurality of light focusing portions, with a grouping of the plurality of convergence points or convergence lines forming an image in a space.