Combined interference device for aspheric surface measurement

Abstract

A combined interference device for measurement of aspheric surface includes a laser, a spatial filter, two beam expanding systems, a beam shrinking system, a spectroscope, a convertible lens, three polarizers, two optical plates, four circular optical wedges with small wedge angle, a beam-dividing grating, a 1 / 4 wave plate, a polarizer group and a CCD. In the device, real-time measurement is realized through simultaneous phase-shifting method, and frequency conversion function is realized through rotating two pairs of double optical wedges. The experimental device adopts common optical elements, so the cost is low, and the device can measure aspheric surfaces of different diameters and is suitable for the plane and the sphere. The real-time high precision measurement in conventional environment can be realized, and the invention has frequency conversion function, which is very effective for treating the mirror surface with discontinuous regions.

Description

technical field [0001] The invention is a combined interferometer integrating radial shearing, fast frequency conversion and synchronous phase shifting, and is mainly used for three-dimensional measurement of aspheric surface shape. Background technique [0002] The use of aspheric optical system can eliminate spherical aberration, coma, astigmatism, field curvature, and reduce light energy loss, so as to obtain high-quality image effects and high-quality optical characteristics, and can be widely used in various modern optoelectronic products, images Dealing with products such as digital cameras, VCD, DVD, computers, CCD camera lenses, large-screen projection TVs and military, astronomical and medical industries. In the processing and experimentation of aspheric optical elements, the precise measurement of their surface shape is crucial; And ultra-precision machining is difficult to achieve. In recent years, people have proposed many aspheric surface measurement technolog...

AI Technical Summary

Problems solved by technology

However, in the transverse shearing interference, the interference area between the original wave surface and the shearing wave surface does not cover the entire pupil surface, and the measured aspheric surface cannot be completely measured, and the results of transverse shearing interferometry in two orthogonal directions are required to recover Raw wave surface, image processing is very troublesome

At the same time, in this technology, the phase shift is driven by piezoelectric ceramics (PZT), and the measurement process requires strict vibration isolation, so it is impossible to achieve measurement in ordinary environments, and it is also difficult to achieve real-time dynamic measurement

[0008] The sixth prior art (referring to P.Hariharan et al., Measurement of aspheric surface using a micro-computer-controlled radial-shear interferometer adopts microcomputer-controlled radial shear interferometer to realize aspheric surface measurement, OpticaActa.31 (9 ), 1984) used radial shearing interferometry combined with phase shift technology to measure the aspheric surface shape. The phase shift is also realized by piezoelectric ceramics (PZT). The measurement process requires strict vibration isolation, so it cannot be realized in ordinary environments. At the same time, it is difficult to achieve real-time dynamic measurement, and it is difficult to change the fringe frequency during the measurement process to adapt to different measured surface shapes. Is there any specific measurement for aspheric surfaces with discontinuous areas (such as spliced ​​aspheric surfaces)? response plan

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