Two-image-point imaging optical device

A two-image-point imaging optical device comprising a plurality of dihedral corner reflectors each including two planer specular surfaces perpendicular to each other, said plurality of dihedral corner reflectors being disposed so that the line of intersection between said two specular surfaces of every dihedral corner reflector is in parallel to that of every other dihedral corner reflector on a first single plane to enable an image to be formed by light emitted from a point light source disposed in space faced by said two specular surfaces with respect to said first plane and reflected once at each of the two specular surfaces of each of said dihedral corner reflectors, said image being observable from a viewpoint set in space on the same side as the point light source with respect to the first plane, wherein:

• a virtual image is formed at a point line-symmetric to said point light source with respect to the line of intersection between said first plane and a second plane that is in parallel to the line of intersection between said two specular surfaces on said first plane and includes said point light source and said viewpoint;
• a real image is formed at the point of intersection between a line including said virtual image and said viewpoint and a line that is parallel to said line of intersection between said two specular surfaces including said point light source;
• and
• the virtual image and the real image are observable from said viewpoint.