| 摘要 |
PURPOSE:To obtain a small branch angle and to set an image-forming characteristic requested for an objective lens to be comparatively smooth by using a refractive index between the maximum refractive index and the minimum refractive index of a uniaxial crystal. CONSTITUTION:The light beam branch prism 13 of an almost a right angled triangle form, which consists of the uniaxial crystal, is arranged in such a way that the slope is set to be the total reflecting surface, two side surfaces which are, almost orthogonal are set to be an incidence surface and an ejection surface and the crystal main axis direction of the prism makes an angle except for zero degree to all the directions of the normal direction of the total reflecting surface, the normal direction of the incidence surface for the total reflecting surface, the normal direction of the reflecting wave surface from the total reflecting surface, the normal direction of a plane decided by the incidence surface normal line and the reflecting wave surface normal line, and the cross line of the plane and the total reflecting surface. |
