INTERFEROMETER FOR CHECKING OBJECT SURFACE LINEARITY AND PLANARITY Russian patent published in 1997 - IPC

FIELD: measuring devices. SUBSTANCE: interferometer has monochromatic light source, telescopic system that functions to extend light beam and incorporates microlens, beam splitter, collimator lens, and beam-splitting grating, planar reflecting grating spaced from beam-splitting one at distance exceeding size of checked object surface, as well as recording device. Collimator lens and beam-splitting grating are built as a single concave reflecting diffraction grating whose optical axis and that of flat reflecting grating are set at an angle equal to diffraction angle of concave reflecting grating. Ratio of dash rate of concave reflecting grating to that of planar reflecting grating is 1: 8. EFFECT: improved checking accuracy, simplified design, reduced size.