Apparatus and method for measuring fringe contrast in a Michelson interferometer and optometry system having the apparatus

摘要

The device has a Wollaston prism arranged at an output of a Michelson interferometer. The prism deviates two perpendicular incident polarizations in two perpendicular analysis directions. A quarter wave plate has its axes aligned with the incident polarizations to provide a phase lag of 90 degrees between the arms. The prism receives a beam at its characteristic angle for obtaining four angularly separated beams. Independent claims are also included for the following: (A) a process for measuring a fringe contrast in an open field Michelson interferometer (B) an eye examination system including a fringe contrast measuring device.