A long-range surface shape measuring device

Abstract

A long trace profile measurement device provided by the present invention is used to carry out the profile detection on the surface of a to-be-tested optical device and comprises a mobile optical head, and the mobile optical head comprises a surface light source, a single-hole screen, a beam splitter, a Fourier transform lens and an area array detector. The beam splitter is attached to the upper surface of the single-hole screen tightly, and the single-hole screen is arranged at one side of the surface light source and has an inclined angle with the surface light source, so that a light beam in the normal direction of the surface light source can pass a screen hole part of the single-hole screen. The beam splitter reflects to the surface of the to-be-tested optical device vertically, the Fourier transform lens is arranged above the beam splitter horizontally, and the area array detector is arranged above the Fourier transform lens horizontally. The long trace profile measurement device of the present invention enables a system error introduced by the lateral movement of a measurement light beam when different angles are measured to be reduced, thereby improving the measurement precision.

Description

technical field [0001] The invention relates to the field of high-precision mirror surface shape detection, in particular to a long-distance surface shape measurement device. Background technique [0002] In the fields of synchrotron radiation, large astronomical telescopes, and extreme ultraviolet lithography, it is necessary to use slender, high-precision mirrors with a length of about 1m and a surface error of less than 0.1 microradians to focus X-rays into nanoscale spots . The shape of this kind of mirror used for focusing directly determines the quality of the x-ray spot, so it needs to be accurately measured. The Long Trace Profile (LTP) is one of the main instruments used to detect the surface shape of such a large-scale, high-precision mirror. [0003] The long-range surface profiler itself is an optical system composed of precision optical components. Its working principle is to inject a reference beam of a specific incident direction onto the optical device to b...

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Problems solved by technology

from figure 1 It can be seen that the measuring beam starts to deviate from the measuring point on the mirror to be tested 6', so the measuring point on the mirror to be tested 6' is the reference point for calculating the lateral displacement of each optical element in the pp-LTP, so for the same The deflection angle of the optical device in the system is farther away from the geometric optical path of the measuring point on the mirror surface 6' to be tested, and the lateral shift of the measuring beam on the optical device is larger. It is this lateral shift that makes each optical device in the system introduce different points of error

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