Optical element surface local gradient surface shape error interference measurement method and device

Abstract

The invention discloses an optical element surface local gradient surface shape error interference measurement method and device. On the premise that an original interferometer light path is not changed, measurement of a local gradient surface shape error which cannot be measured before is achieved; a double-optical-wedge compensator is placed in a local steepness surface shape error area, and therelative rotation angle of the double-optical-wedge compensator and the overall roll angle around an optical axis are rotated to generate a direction-adjustable additional inclination compensation phase, so that a local measurement light beam is matched with a local surface shape, interference fringes become sparse, and an interferometer is used for measuring the local phase; the introduced phaseis calculated according to the rotation angle of the double-optical-wedge compensator and input into a virtual interferometer model, and calculation is carried out to obtain a local surface shape error; sequentially, the measurement process is carried out on all local parts which cannot be directly measured by the optical element until all local gradient surface shape errors are measured; and splicing is conducted on the local surface shape error and the full-aperture surface shape error data of the optical element to complete measurement.

Description

technical field [0001] The invention relates to the technical field of photoelectric detection, in particular to an interferometric method for measuring the local steepness surface error of the surface of an optical element, and a corresponding interferometric device for measuring the local steepness surface error of the optical element surface. Background technique [0002] With the continuous advancement of science and technology, the precision and imaging quality requirements of optical systems are getting higher and higher. Optical systems containing aspheric optical elements can eliminate aberrations such as spherical aberration, coma, and curvature of field, and can reduce light energy loss. , the measurement of aspherical components has also become the focus of optical system design and manufacture, and the types of detection technologies are also increasing. These methods can be roughly classified into contact measurement and non-contact measurement. The contact det...

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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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