| 摘要 |
PURPOSE:To make possible the separate observation of symmetrical and non- symmetrical components of the aberration of the lens to be inspected by disposing a semispherical lens having the radius of curvature at the focal point of the lens. CONSTITUTION:When observing the symmetrical components of the aberration, that is, when desired to see the interference stripes of waves (a) and (b), the semispherical lens 3 is shifted in a direction perpendicular to the optical axis. The reflected light or wave (c) from a spherical surface 3'' is condensed at a position offset from the center on a spatial filter surface 8. This rays of light are cut so that only the symmetrical aberration of the lens to be inspected is observed. When observing non-symmetrical aberration components, that is, when it is desired to see the interference stripes of the waves (b) and (c), a plane surface primary standard 1 is tilted slightly. At this time, the reflected light or a wave (a) from the standard 1 is cut by the spatial filter 8 so that only the non-symmetrical aberration of the lens to be inspected is observed. When observing the overall aberration, that is, when it is desired to see the interference stripes of the waves (a) and (c), the standard 1 and the lens 3 are inclined by the same angle and the spatial filter 8 is moved therewith so that only the wave (b) is cut by the filter 8 so as to permit the observation of the overall aberration. |
