Long trace profile

Abstract

A long trace profile 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 scanning optical head and a f-theta angle detection system. The scanning optical head comprises a surface light source, a beam splitter, a single-hole screen and a plane mirror. The surface light source is placed horizontally, the beam splitter is arranged below the surface light source aslant, the single-hole screen is attached to the bottom surface of the beam splitter tightly, and the plane mirror is arranged below the single-hole screen aslant and forms a dual-reflection surface of a similar pentaprism structure with the beam splitter. According to the present invention, a system error introduced by the lateral movement of a measurement light beam when different angles are measured is 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 measuring instrument. Background technique [0002] In the fields of science and technology such as large-scale astronomical telescopes, extreme ultraviolet lithography, and synchrotron radiation optical engineering, 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. The production and use of such high-precision optical devices depends on high-precision surface detection technology. [0003] The Long Trace Profile (LTP) based on the principle of point-by-point scanning of thin beams is one of the main instruments used in the detection of such high-precision optical devices. Point-by-point scanning is carried out on the optical device. Since the normal direction of different points on the optical device is different, the reflected light is ref...

AI Technical Summary

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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