Patent ID: 7965448

Claim:
A real mirror image forming optical system, comprising: a half-mirror, and a retroreflector comprising a set of unit retroreflective elements placed in such positions where the light transmitted through said half-mirror, or reflected by said half-mirror, is recursively reflected by them; wherein light, emitted from an object to be projected placed at the back side of said half-mirror, passes through said half-mirror, then it is recursively reflected from said unit retroreflective elements, then it is reflected from the front side of said half-mirror, thus forming a first light path; or light, emitted from an object to be projected placed at the back side of said half-mirror, is reflected from the back side of said half-mirror, then it is recursively reflected from said unit retroreflective elements, then it passes through said half-mirror, thus forming a second light path; and light passing through one or both of said light paths forms the real mirror image of the object to be projected at a planar symmetric position with respect to the surface of said half-mirror, wherein said unit retroreflective elements constituting said retroreflector are arranged along a common curved surface.