METHOD FOR MEASURING DISTORTION IN INTERFEROGRAM OF OPTICAL ASPHERICAL SURFACE Russian patent published in 2022 - IPC G01B9/00 

FIELD: telescopes’ mirrors.

SUBSTANCE: invention is used in the finishing and inspection of large-sized aspherical off-axis mirrors of telescopes. In the process of interferometric control of the shape of an off-axis aspherical mirror using an interferometer and a wavefront corrector in the form of a combined diffractive optical element (DOE), including the main diffractive structure and additional centering and focusing structures, the DOE is installed in the coverage area of the controlled aspherical surface, the interferometer is adjusted relative to the DOE with using a centering diffractive structure, and the DOE interferometer relative to a controlled off-axis aspherical surface using auxiliary focusing structures. On the surface of the mirror, the work points of the places (zones) to be processed are marked with marks, the coordinates of the work points are determined, the interferogram is recorded, and the coordinates of the images of the work points are determined on it. The magnitude of distortion displacements in the interferogram is determined, i.e. the difference between the coordinates of the points on the interferogram on a scale, reduced to the dimensions on the surface of the part, and the coordinates of the same points on the controlled surface х_i,j, у_i,j, z_i,j, namely, the coordinates of the points are shifted on the interferogram by a given amount of corrections, bringing them to the position of the same points on the surface details.

EFFECT: more productive, faster and more accurate (up to several hundredths of a millimeter) measurement of distortion in the interferogram, and as a result, more accurate shaping of off-axis aspherical surfaces.

1 cl, 8 dwg