Convex aspheric surface reflector surface shape detection device and method

Abstract

The present invention discloses a convex aspheric surface reflector surface shape detection device and method which can detect a convex aspheric surface reflector of a large caliber (the caliber is more than 200 mm) by using a CGH compensator of a small size on the condition of guaranteeing the detection precision. The device of the present invention converges the light beams via a lens, so that the caliber of the adopted CGH compensator is very small, and the CGH compensator can realize the high-precision detection of the surface shape of the convex aspheric surface reflector of the large caliber within a high-precision processing size range. The method of the present invention is characterized by combining the phase difference compensation effect of the CGH compensator to the wavefrontsand the convergence effect of the lens to the light beams and using the CGH compensator of the small size to detect the convex aspheric surface reflector of the large caliber, solves the problems thata conventional CGH compensation detection method only can detect the surface shape of the convex aspheric surface reflector of the small caliber, and can detect the convex aspheric surface reflectorsof various curved surface types by being compared with the conventional convex aspheric surface reflector surface shape detection method.

Description

technical field [0001] The invention relates to the technical field of mirror surface detection, in particular to a convex aspheric reflective mirror surface shape detection device and detection method. Background technique [0002] The use of aspheric optical elements in the optical system can achieve the purpose of improving system performance, improving image quality and reducing the number of optical elements, making the optical system compact and light. Therefore, aspheric optical elements are widely used in many optical instruments such as aerospace, astronomical observation, lithography objective lens, high-performance camera or camera lens. [0003] High-precision surface shape detection is the premise and foundation of precision machining. As the market has higher and higher requirements for the specifications and precision of convex aspheric mirrors, further requirements have been put forward for the surface shape detection of convex aspheric mirrors. Commonly use...

AI Technical Summary

Problems solved by technology

When the aperture of the convex aspheric mirror to be inspected is within 200mm, the above methods can be better dealt with, but when the aperture of the convex aspheric mirror to be inspected is larger than 200mm (large aperture), these methods are due to their own limitations. Limitations make it difficult for these detection methods to continue to be used in the surface shape detection of large-aperture convex aspheric mirrors

[0004] Among them, the disadvantages of the imageless point detection method are: (1) Inherent disadvantages: only the surface shape detection can be performed on the quadric surface, and the convex ellipsoid and high-order aspheric surface cannot be detected, and there is a central occlusion; (2) when When the diameter of the convex aspheric mirror to be inspected is larger than 200mm, it is necessary to manufacture a spherical auxiliary mirror with a larger diameter, which is generally twice or even larger than the diameter of the convex aspheric mirror to be inspected, and the surface shape accuracy of the auxiliary mirror is required to be higher. high

[0005] When the aperture of the convex aspheric mirror to be inspected is greater than 200mm, the disadvantages of the lens compensator detection method are: (1) a large-diameter interferometer 1 is required; (2) a large-diameter lens compensator needs to be manufactured, and the lens compensator is A set of lens groups requires high processing accuracy and is difficult to process; (3) The reference surface of the lens compensator is generally an aspheric surface, so it is necessary to manufacture additional inspection tools to detect the surface shape of the reference surface, and the lens compensator It is necessary to carry out targeted design for the mirror to be inspected, and its universality is poor. Therefore, when the diameter of the mirror to be inspected exceeds 200mm, the detection cost of this method is huge

[0006] The disadvantages of the CGH compensation detection method are: (1) the caliber of the CGH compensator 3 must be larger than the caliber of the convex aspheric mirror to be tested; (2) limited by the existing manufacturing process of the CGH compensator 3, when the detection accuracy is guaranteed The manufacturing diameter does not exceed 200mm, so it can only detect small and medium-diameter convex aspheric mirrors

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