| 摘要 |
<p>There is described an optical system suitable for use on highway pavements or marking indicia for ensuring nighttime visibility, and consisting of a transparent sphere, a transparent layer of a binding medium having a refractive index different from that of the sphere, and partially surrounding said sphere, and a plurality of reflective part-spherical surfaces about such medium. The system has an optical transition zone between said sphere and said binding medium, consisting of a transparent layer of finite thickness wherein the index of refraction progressively varies from a value equal to that of the sphere, at locations adjacent to the sphere, to a value equal to that of said medium, at locations adjacent to the layer of said medium, whereby the refractive deviation of the light rays from the media (sphere and binding medium) having different refractive indexes occurs through said intermediate layer in form of a progressively curved path.</p> |
