| 摘要 |
PURPOSE:To prevent or lower the waveform distortion by multireflected light by forming a light incident surface and exit surface of nonparallel light transmissive members and forming thin films exhibiting prescribed transmittance on a part of the surfaces. CONSTITUTION:This light attenuator is constituted of a transparent plate 2 consisting of, for example, glass having the light incident surface 61 and light exit surface 62 intersecting each other at a vertex theta. The thin films (for example, SiO2 films) 9 having the prescribed transmittance are formed on one or both of these surfaces. Incident light 4 entering this surface 61 approximately perpendicular thereto is refracted by the transparent plate 2 and is then made into exit light 7 emitted from the surface 62. The incident light 4 is partly reflected by the surface 62 and is again reflected by the surface 61 to the multireflectecl light 8. The exit angle beta of the multireflected light light 8 is larger than the exit angle alpha of the exit light 7. These exit light rays 7, 8 advance in different directions. Then, the taking out of the light in which the waveform distortion occurring in the exit light 8 is not generated is possible if the lens 10 having a numerical aperture on which the exit light 8 is not made incident on the optical axis of the exit light 7. |
