High-precision photoelectric autocollimator based on the design of far exit pupil and small pupil diameter ratio

Abstract

The invention relates to a high-precision photoelectric auto-collimator based on a far exit pupil and small diameter ratio design. The high-precision photoelectric auto-collimator belongs to the technical field of photoelectric measuring instruments. The high-precision photoelectric auto-collimator comprises a light source, a condenser lens, an aperture diaphragm, a convergent lens, a pinhole, a polarization beam splitting prism, a lambda / 4 wave plate, a collimating objective lens and a detector. The aperture diaphragm is additionally arranged in an illumination light path, an image of the aperture diaphragm, namely, an exit pupil, formed through a collimator optical system is positioned behind the collimating objective lens, and the diameter of the exit pupil is less than the aperture of the collimating objective lens. A target lens is arranged near the exit pupil position. By controlling the relation among exit pupil distance, exit pupil diameter and the aperture of the collimating objective lens, the aperture of a light beam reflected by a measured mirror is ensured to be less than the aperture of the collimating objective lens, light beam cutting is eliminated, and measurement errors caused by cutting are avoided. A polarization stray light blocking technology of combining the polarization beam splitting prism with the lambda / 4 wave plate is adopted in a self-collimating light path, and stray light interference of multiple reflections of an optical surface is effectively suppressed.

Description

technical field [0001] The invention relates to a high-precision photoelectric autocollimator designed based on a far exit pupil and a small pupil diameter ratio, and belongs to the technical field of photoelectric measuring instruments. Background technique [0002] Photoelectric autocollimator is a small-range, high-precision angle measuring instrument. The existing photoelectric autocollimator aperture diaphragm is usually designed on the collimating objective lens, that is, the exit pupil is set on the collimating objective lens, and the pupil diameter ratio is 1. When the measured mirror is not ideally perpendicular to the optical axis, the reflected light from the autocollimator has a certain angle with the optical axis, the beam will be cut by the self-collimating objective lens frame, and only a part of the reflected light can enter the photoelectric autocollimator. The light intensity distribution of the focal plane spot is affected by the aberration and diffractio...

AI Technical Summary

Problems solved by technology

Therefore, the focal plane spot distribution is usually no longer symmetrical

For photoelectric autocollimators that use methods such as centroid, peak position, and energy center position to detect the offset of the pinhole image, and then calculate the light deflection angle, it will inevitably affect the angle measurement accuracy

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