| 摘要 |
<p>PROBLEM TO BE SOLVED: To facilitate the ingress of incident light such as sunlight by applying the constitution that one set of cells having roughly spherical surface on the inner side thereof for diffusing light is formed to have two flat facet sets on the external surface in such a state as inclined for the plane of an intermediate screen. SOLUTION: The focal point of a parabolic mirror 20 as a beam reflector is laid on the filament 11 of a light source 10, and an intermediate screen 30 and a cover lens 40 are arranged within an approximately orthogonal plane for the direction of the whole of incident beams formed out of the principal axis of the paraboloid of the parabolic mirror 20. Also, a center facet 32a, an upper facet 32b and a lower facet 32c are respectively provided on the external surface of the intermediate screen 30 interlocked with each spherical surface 31, so as to be orthogonal with the optical axis of the light source 10. In this case, the upper facet 32b and the lower facet 32c are symmetrically inclined so as to enable the three facets to form hollow surface. As a result, the ingress of incident light like sunlight can be facilitated.</p> |
