Novel directional projection screen using divergent corner cube retroreflector with a three-sided curved surface (D-CCR)

摘要

We devised and developed a novel directive projection screen for applications such as personal use, small group meeting, automotive pillar, and near-eye. This screen reflects diffused light at an angle (view) around a direction deviated by theta(view) from the direction of the projector. By applying this screen to automobiles, for example, by installing a projector at a position slightly shifted from the driver, it is possible to reflect the projected light with high efficiency to a certain range around the face of driver. To realize such a characteristic, a hollow corner cube retroreflector (CCR) was modified as follows. The bottom surface of the CCR was tilted by theta(view)/2 to change the direction of the reflected light by theta(view) from the retroreflection direction. In addition, three sides' surfaces of the CCR were curved, so that the light to be diffused within a designed angle (theta(view) +/- Delta theta(view)/2). The novel retroreflector CCR (D-CCR) has a single divergent surface with a three-sided curved surface. We fabricated a prototype with theta(view)=10 degrees and theta(view)=16 degrees (i.e., the viewing angle for a single D-CCR, 10 degrees +/- 8 degrees), simulated, and measured its optical properties. We closely confirmed the desired characteristics in which an optical gain of 16 was obtained.