High-precision angle measurement device and method

Abstract

The invention proposes a high-precision angle measurement device and method. A laser source passes through a beam expander and an attenuation piece and then becomes beam-expanding parallel laser. Thebeam-expanding parallel laser passes through a first beam splitter, a reflector, a third beam splitter and a fourth beam splitter to form a first reference light beam. The beam-expanding parallel laser passes through the first beam splitter, a second beam splitter, the third beam splitter and the fourth beam splitter to form a second reference light beam. The beam-expanding parallel laser passes through the first beam splitter, the second beam splitter, a to-be-detected reflector and the fourth beam splitter to form a to-be-detected light beam. The first reference light beam, the second reference light beam and the to-be-detected light beam are coherent and overlapped on an image plane of a CCD camera to generate an interferogram, and the interferogram is inputted into an image processingsystem. Through the measurement of the position information of laser interference light spots, the linear fitting of position information and the calculation of the variation of the linear distance, the angle change of the incident laser is calculated. The method avoids the strict requirements for the distance under the same measurement precision, and provides a method for the miniaturization of the high-precision angle measurement equipment.

Description

technical field [0001] The invention belongs to the field of optical metrology, and mainly relates to a high-precision angle measuring device and method for small angle changes. Background technique [0002] With the development of technology, sub-micro radian angle measurement has become an important problem that many high-tech technologies urgently need to solve. The collimated light tube method or the four-quadrant method is mostly used now. The measurement accuracy of the collimated light tube method is high, but the equipment is heavy, the environmental requirements are high, and the adjustment is difficult. For example, the focal length of the objective lens for measuring sub-micro-radian angles must reach 2m, which requires a lot of space. The sensitivity of the position of the four-quadrant method is high. Assuming that the distance from the reflector to the four-quadrant detector is 2.5m, the sensitivity of this method reaches 1μrad. However, because the laser spo...

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