Device and method for detecting surface topography of off-axis elliptic cylindrical mirror

Abstract

The invention provides a device and a method for detecting the surface topography of an off-axis elliptic cylindrical mirror, belongs to the field of optical interference detection, is used for detecting the surface topography of an off-axis elliptic cylindrical mirror to be detected, and is characterized in that the device for detecting the surface topography of the off-axis elliptic cylindrical mirror comprises" an interferometer used for emitting planar light waves; a compensation element which is arranged in front of the focus of the interferometer and is used for converting the planar light waves into cylindrical light waves as detection light and reflecting the planar light waves emitted by the interferometer as reference light; a to-be-detected mirror clamp which is arranged in a light path of the detection light, is positioned on one side, far away from the interferometer, of a convergence position of the detection light, and is used for fixing the off-axis elliptic cylindrical mirror and adjusting the position and the inclination angle between the off-axis elliptic cylindrical mirror and the interferometer; and a reflecting mirror which is arranged in a light path of first reflected light formed by reflecting the detection light through the off-axis elliptic cylindrical mirror and is positioned on one side, far away from the to-be-detected mirror clamp, of a convergence position of the first reflected light.

Description

technical field [0001] The invention belongs to the field of optical interference detection, in particular to a method for detecting the surface topography of an off-axis elliptical cylindrical mirror Background technique [0002] With the continuous development of optical processing and detection technology, aspheric surfaces are more and more widely used in optical systems. The off-axis quadratic aspheric surface is used as a part of the quadratic aspheric body because it has the advantages of simplifying the optical system, improving the imaging quality of the optical system, increasing the field of view, reducing the size and weight of optical instruments, and avoiding the problem of occlusion of the optical system. It has been widely used in modern optical fields such as astronomical instruments and space optical systems due to its influence and other characteristics. Although the aspheric optical element has advantages to a certain extent, it is difficult to process a...

AI Technical Summary

Problems solved by technology

For the non-interferometric measurement process, the contact measurement method requires the probe to be in contact with the surface to be measured, which will cause a certain degree of damage to the surface shape of the surface to be measured; while the sample comparison method has a higher impact on the processing of the sample. Requirements and applicable detection range is very small, there are limitations

In the interferometric method, the optical holography method must have a reference aspheric entity, and the production of high-precision holograms is also difficult, and the reset accuracy of the optical hologram has a greater impact on the detection accuracy.

The computational holographic method requires a large amount of calculation for the holographic sample, and has strict requirements on the reset accuracy of the holographic sample, and the computational holographic method is a one-to-one detection method, which has poor versatility

The aberration-free detection method can only detect some secondary off-axis aspheric surfaces with perfect imaging points, which limits its application range

Aperture stitching, its corresponding stitching algorithm needs to use overlapping areas for stitching, so the adjustment and alignment errors in the detection process are difficult to eliminate, and the stitching algorithm will inevitably introduce errors

[0004] The off-axis elliptical cylindrical mirror is a special off-axis aspheric surface, the above methods are not suitable for the measurement of off-axis elliptical cylindrical mirror

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