No abstract

We devised and developed functional projection screen for personal use, small meetings, car pillars, and near‐eye projection. The screen deflects incident light from a projector by a fixed angle θview and diffuses in a certain angular range Δθview. We have realized the screen by modifying the fine structures based on the corner cube reflector (CCR) and reported basic concept and optical characteristics at IDW2017 and SID2018. However, there remained issues of light in unnecessary direction and insufficient uniformity of the diffused light. In this paper, we report on further modification of the fine structures by optimizing the inclination angles of three curved surfaces of the CCR that result in change of the diffused light pattern. Consequently, the modifications of the deflection angle θview and the diffusion angle Δθview resulted in significant improvement in the screen characteristics. These new results were applied to the screen for personal use and car pillar applications.

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 and diffuses incident light at an angle  view around a direction deviated by  view from the direction of the projector. We realized the screen by employing a hollow cube corner retroreflector (CCR). The bottom surface of the CCR was tilted by  view /2 to change the direction of the reflected light by  view from the retro-reflection direction. Furthermore three side surfaces of the CCR (D-CCR) were curved to diffuse the light within a designed angle ( view ± view /2). We simulated a D-CCR with  view =10° and  view =16°, i.e., the viewing angle for a single D-CCR, 10°±8°, and fabricated a prototype. We verified closely the desired characteristics in which an optical gain of 16 was obtained.

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 Δθview around a direction deviated by θview 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 θview/2 to change the direction of the reflected light by θview 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 (θview ± Δθview/2). The novel retroreflector CCR (D‐CCR) has a single divergent surface with a three‐sided curved surface. We fabricated a prototype with θview = 10° and Δθview = 16° (i.e., the viewing angle for a single D‐CCR, 10° ± 8°), simulated, and measured its optical properties. We closely confirmed the desired characteristics in which an optical gain of 16 was obtained.