Detecting device and method of shape of optical convex spherical surface

Abstract

The invention provides a detecting device and method of the shape of an optical convex spherical surface. In the device, a light source emits wavelength-variable linear polarization quasi monochromatic light and the wavelength-variable linear polarization quasi monochromatic light is focused at the center of a small hole after passing through a filtering hole, a first beam expander, a spatial filter, a second beam expander, a lambda / 4 wave plate and a first focusing lens. A part of small hole diffracted waves irradiate onto the surface of the detected convex spherical surface through a second focusing lens, after being reflected, the part of small hole diffracted waves form detection light beams, and the light beams are focused near the small hole through the second focusing lens, are reflected on the back face of a small hole diffraction plate and then interfere with the other part of small hole diffracted waves serving as reference light beams. The detected spherical surface is replaced by a random ball, the spherical center coincide with the spherical center of the detected spherical surface, and errors, introduced by the second focusing lens, of a focusing system are calibrated through multiple times of measurement. According to the detecting device and method of the shape of the optical convex spherical surface, the small diffraction waves approaching ideal spherical surface are used as the reference waves, the errors of the focusing system are calibrated through multiple times of measurement by the adoption of the random ball method, and therefore high-precision measurement of the shape of the optical convex spherical surface can be realized.

Description

technical field [0001] The invention belongs to the field of optical measurement, and in particular relates to a detection device and method for an optical convex spherical surface shape. Background technique [0002] In modern optical surface processing, the main detection tool is the interferometer. However, general commercial interferometers use Fizeau type and Tieman-Green type, and use the reference surface to generate reference spherical waves. Due to the limitation of machining accuracy, the accuracy of the reference surface is generally less than λ / 50, which makes the detection accuracy far from meeting the requirements of ultra-high precision surface shape detection. [0003] Small holes or single-mode fiber diffraction can generate diffracted waves that are very close to ideal spherical waves. Using them as reference waves can get rid of the limitation of the precision of the reference surface and improve the detection accuracy. The diameter of the small hole or ...

AI Technical Summary

Problems solved by technology

[0006] The fiber core diameter generally can only reach 2 μm ~ 3 μm, and it is difficult to make the half-mirror that meets the requirements on the end face of the fiber core.

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