Optical device, optical system, and ticket gate

An optical device comprising:

• a plurality of light sources;
• and
• a light-guiding plate that guides light emitted from the plurality of light sources in a plane parallel to an emission surface that emits light, the light guiding plate comprising a plurality of convergence portions that receive light guided by the light-guiding plate, each of the plurality of light convergence portions corresponding to one of a plurality of convergence points in a space outside the light-guiding plate and comprising optical surfaces that cause light to be emitted from the emission surface such that:
• the light substantially converges at the corresponding convergence point in the space;
• or the light substantially scatters from the corresponding convergence point in the space, wherein:
• angles that optical axes of the plurality of light sources form with the plane parallel to the emission surface are different from each other;
• the convergence points for the plurality of light convergence portions are different from each other, and an image is formed in the space on an emission surface side by a collection of a plurality of the convergence points;
• and
• a plurality of first light convergence portions from among the plurality of light convergence portions is provided at positions that are different from each other along a light-guiding direction in which the light-guiding plate guides light, and causes light to be emitted from the emission surface in different directions in which the light:
• substantially converges at a first convergence point among the plurality of convergence points;
• or substantially scatters from the first convergence point.