| 摘要 |
An improved method and apparatus for profiling surfaces is provided. The subject apparatus avoids the earlier used constructions of such apparatus in the normally used Fizeau interferometer form, and instead uses a retroreflector (200) located at the end of the optical path (128) of the beam reflecting off of the surface under test (150) in order to achieve alignment-free surface profiling. In addition, in a second embodiment, a second retroreflector (140') is used to assure a more accurate result. While in yet another improvement, the retroreflector (200) is selectively moveable in relation to the optical path of the beam, to compensate and correct for a shearing effect resulting from the use of variously sized (thicknesses) flats under test.
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