A method and device for interferometric measurement of local steepness and shape error on the surface of an optical element

Abstract

A method and device for interferometric measurement of local steepness surface error on the surface of an optical element realizes the measurement of previously unmeasurable local steepness surface error without changing the optical path of the original interferometer. The dual optical wedge compensator is placed in the area of ​​local steep surface error, and the relative rotation angle of the dual optical wedge compensator and the overall roll angle around the optical axis are rotated to generate an additional tilt compensation phase with adjustable direction, so that the local measurement beam Match the local surface shape, the interference fringes become sparse, and use the interferometer to measure the local phase; calculate the introduced phase according to the rotation angle of the double optical wedge compensator, input the virtual interferometer model, and calculate the local surface error; for the optical element All the parts that cannot be directly measured are followed by the above measurement process until all the local steepness surface errors are measured; the local surface error is spliced ​​with the full-aperture surface error data of the optical element to complete the measurement.

Description

technical field [0001] The invention relates to the technical field of photoelectric detection, in particular to a method for interferometric measurement of the surface shape error of the local steepness on the surface of an optical element, and a corresponding interferometric measurement device for the surface shape error of the local steepness of the optical element surface. Background technique [0002] With the continuous advancement of science and technology, the requirements for the accuracy and imaging quality of optical systems are also getting higher and higher. Optical systems including aspheric optical elements can eliminate spherical aberration, coma, field curvature and other aberrations, and can reduce the loss of light energy , the measurement of aspherical components has also become the focus of the design and manufacture of optical systems, and the types of detection techniques are also increasing. These methods can be roughly classified into two types: cont...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide a method for interferometry of the local steepness and surface error of the surface of the optical element, which solves the problem of spherical or aspheric optics in the detection process of the laser interferometry technology. The problem that the local steepness surface error cannot be measured when the component surface is shaped, and the measurement of the previously unmeasurable local steepness surface error can be realized without changing the optical path of the original interferometer. The structure is relatively simple and no complicated full-aperture mechanical scanning is required. The structure saves cost while expanding the measurement range, and retains the high precision of interferometry. It is suitable for the measurement of local steep surface error distribution in the processing of various optical surfaces such as plane, spherical, and aspheric surfaces. It has strong practicability

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