METHOD OF MEASURING THE SURFACE PROFILE OF OPTICAL PARTS USING LASER PHASE-SHIFTING INTERFEROMETRY Russian patent published in 2020 - IPC G01B9/02 

FIELD: measurement technology.

SUBSTANCE: invention relates to non-contact optical measurements and can be used for measuring the surface profile of optical parts. Method comprises forming a beam of continuous single-mode laser radiation at a wavelength λ, dividing it in a Fizeau interferometer into two beams, one of which is directed to the photodetector matrix of the video camera after reflection from the reference surface mounted on the piezoelectric actuator, and another beam is directed to the surface of the tested optical part, and the radiation reflected therefrom is directed to the photodetector matrix of the video camera to form a sequence of interference patterns, which is used to measure the parameters of the surface profile of the optical part along the shift axis, which is carried out using a piezoelectric actuator, wherein the λ wavelength of the single-mode laser radiation is selected from the condition

where λ₀ is short-wave boundary of spectral area of optical transmission of reference plate of Fizeau interferometer, α^-1 is function inverse to α(λ), dependence of radiation absorption coefficient α in material of analyzed sample on wavelength λ, n is the refraction index in the material of the analyzed sample for radiation with wavelength λ, d is the thickness of the analyzed sample, k is the maximum number of steps of amplitude sampling of the digital video camera signal converter used to record the interferograms.

EFFECT: technical result consists in improvement of reliability and accuracy of measurements and increased efficiency.

1 cl, 4 dwg