Device for detecting surface shape of optical aspheric surface by sub-aperture stitching interferometer

Abstract

The invention relates to a device for detecting a surface shape of an optical aspheric surface by a sub-aperture stitching interferometer, which comprises an interferometer, a transmission sphere, an adjusting mechanism, a numerical control device and a computer, wherein parallel light emitted by the interferometer is changed into a standard spherical wave through the transmission sphere; the computer controls the action of the adjusting mechanism by the numerical control device to adjust the relative position of the interferometer and an aspheric surface to be detected so that the standard spherical wave is incided to each sub-aperture of the detected optical aspheric surface sequentially and returns to the interferometer; and the computer extracts phase distribution data of each sub-aperture measured by the interferometer for analysis and processing, and the error distribution of the surface shape of a full aperture of the detected optical aspheric surface is obtained by a stitching algorithm. The device broadens horizontal and vertical dynamic range tested by the interferometer, can detect surface shapes of large-aperture concave and convex aspheric surfaces and an off-axis aspheric surface in high resolution and high precision without other auxiliary optical elements, and has low testing cost and short construction period.

Description

technical field [0001] The invention relates to a device for detecting the surface shape of an optical aspheric surface, in particular to a device for detecting the surface shape of an optical aspheric surface by sub-aperture splicing interference. Background technique [0002] At present, there are many methods for detecting the shape of optical aspheric surfaces, such as profilometry, Ronchi grating method, Moiré fringe method, laser scanning method and so on. However, most of these detection methods can only detect the surface shape of the aspheric surface qualitatively, and there are subjective and human errors. Even if the surface shape of the aspheric surface can be detected quantitatively, it is only suitable for medium and low-precision aspheric mirrors or some quadric surfaces. measurement, or only as an intermediate inspection of the grinding process. Using an interferometer, compensator or CGH (computational holography), zero compensation interferometry on aspher...

AI Technical Summary

Problems solved by technology

However, for a large-aperture interferometer, its spatial resolution is generally limited to the detection of wavefront information with a spatial wavelength greater than a few millimeters, and the higher-frequency information is cut off by the system

Therefore, the resolution of the existing large-aperture phase-shift interferometer cannot meet the requirements of the middle and high frequency band analysis.

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