Long-range surface shape detector and detection method

Abstract

The invention relates to a long-range surface shape detector and a detection method. The detector includes a light source, a beam splitter, a double mirror unit constituting an equivalent pentaprism, a Fourier transform lens and an area array detector; The beam mirror and the double mirror unit reach the surface of the optical device to be tested, and after being reflected, go through the double mirror unit, the beam splitter, and the Fourier transform lens to the area array detector to form a measurement spot; the double mirror unit includes two planes Reflector, two plane reflectors can rotate independently along their respective rotary axes, the two rotary axes are located on the same plane with an angle of 45°, the plane reflector and its rotary axis are oblique and the formed angle is required by the range It is set to change the angle of the outgoing light path after being reflected by the double-mirror unit through rotation, and make the outgoing light path incident on the surface of the optical device to be tested in the form of normal incidence; the surface shape of the optical device to be tested can be reflected by two planes The rotation amount of the mirror is obtained, thereby improving the detection accuracy.

Description

technical field [0001] The invention belongs to the technical field of long-range mirror surface shape detection, and in particular relates to a long-range surface shape detector and a detection method. Background technique [0002] With the continuous development of science and technology, various application fields have put forward higher requirements for the detection of mirror surface shape. In order to improve the detection capability of the long-range surface profiler, it is necessary to correct or eliminate various system errors. Among these system errors, the most important type is introduced due to the slight difference between the optical elements used in the optical path system of the long-range surface profiler and the ideal optical elements, which are mainly manifested in two aspects: [0003] On the one hand, the small processing difference between the surface shape of each reflective optical element in the optical path system and the surface shape of the idea...

AI Technical Summary

Problems solved by technology

[0009] As can be seen above, in the existing long-distance surface shape measurement technical solutions, the purpose of reducing optical elements and reducing optical elements that introduce errors is achieved through structural changes, and the systematic error has not been completely or better eliminated, and through The difference between the landing points of the measuring spot on the area array detector (CCD) of the f-θ angle detection system is used to feed back the surface shape of the optical device under test, and there are also area array detectors inevitably. The processing inhomogeneity of pixels, the inconsistency of photoelectric response efficiency, and the consistency of electronic circuits, etc., lead to system errors. In theory, the greater the distance between the Fourier transform lens and the area array detector, the higher the resolution , in the current detection form, the larger the distance, the more errors will be introduced at different points on the area array detector (CCD), which is contradictory

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