| 摘要 |
PURPOSE:To stably measure data on the wave front aberration of a lens to be inspected by judging the presence and absence of dropout in the case of calculating the wave front aberration from an interference fringe image and calculating the wave front aberration of the lens to be inspected excepting the information in such a case. CONSTITUTION:The title device has such a constitution that light from an excimer laser oscillator 1 is splitted by a beam splitter 4, which is made to pass through a measuring optical system 5 including a projection lens 53 and a reference optical system 6 including a movable wedge glass 61 for modulating phase and return to an original optical path, and the interference fringe generated by said light is picked up in terms of image by a TV camera 7 so as to calculate the data on the wave front aberration. The beam is fetched by a beam splitter 2 and made incident on a dropout monitor 3 so as to detect the dropout and computation is performed excepting the information at that time. Thus, the data on the wave front aberration of the lens to be inspected can be stably measured even if the laser light beam generates the dropout. |
