Reduction of retro-reflector and expansion of the viewpoint of an aerial image by the use of AIRR with transparent spheres

Abstract

This paper proposes a novel optical system to form an aerial image over a transparent sphere. The proposed optical system is composed of two transparent acrylic spheres in the light path of the aerial imaging by retro-reflection (AIRR) device. The first sphere collects the diverging light rays from a light-source display. The second sphere converges retro-reflected light rays to the aerial image. Raytracing simulation results shows that the area of light entering the retro-reflector can be reduced. Furthermore, this reduction of retro-reflector has been confirmed with a prototype aerial display by the use of a piece of retro-reflector. Thus, the proposed optical system features reduction in the area of expensive retro-reflector.