| 摘要 |
PURPOSE: To provide a device that controls the amount of light passing a prismatic outer surface of a reflector having a total reflection prism and facilitates a change for passing a preselected amount of light that can easily be introduced into the reflector and is different from a reflector to another. CONSTITUTION: A reflector 16 has many double-reflector right-angle prisms on its outer surface, and the prisms are formed side by side along the outer surface at positions spaced at intervals. The prisms each are a double-reflection prism, and each of them has a pair of reflecting surfaces disposed so as to effect total reflection of a large percentage of the beam entering the prism from a sight source 18. For controlling the amount of light passing from the light source 18 through the prismatic outer surfaces of the reflector 16, an additive in particle form is dispersed within the transparent reflector material and serves to divert some of the beam entering the prisms into paths that intersect the reflecting surfaces at angles less than the critical angle of incidence, and thereby, the diverted beam pass through the prismatic outer surfaces. |
