Large aperture optical system near-field detection device and measuring method thereof

Abstract

A large aperture optical system near-field detection device and a measuring method thereof are provided; a collimating mirror, a microlens array and a detector form a Shack-Hartmann Wave-front measuring device; the features are that a spot light source array is arranged in front of a measured object to serve as a measuring beacon; a spectroscope and a scaling spot light source are arranged in front of the focal point of the measured object; the collimating mirror, the microlens array and the detector are arranged in order behind the focal point; the spot light source array, the measured object, the spectroscope and the scaling spot light source form a system self-check optical path; the spot light source array, the measured object, the spectroscope, the collimating mirror, the microlens array and the detector form the measuring optical path. The method uses the correlation of the third-order aberration in an entrance pupil position as the theory basis, uses the near field spot light source array as the measuring beacon, thus realizing large aperture optical system near-field detection; the method and device can be widely applied to detection of large optical systems under indoor and beacon-free conditions.

Description

technical field [0001] The invention relates to a large-diameter optical system near-field detection device and a measurement method thereof. The present invention is carried out under the support of the National Natural Science Foundation of China (project number: U1631125), and belongs to the field of optical measurement technology. Background technique [0002] With the rapid development of deep space exploration technology, astronomers have higher and higher requirements for optical telescopes. Building large-aperture and high-precision astronomical telescopes is a direction and hot spot in the development of today's astronomical optical technology. In the development process of astronomical optical telescopes, limited by technical conditions such as glass materials, processing, and adjustment, large-aperture optical telescopes mostly use splicing mirror technology, such as the Guo Shoujing Telescope (LAMOST) in China, and the Thirty Meter Telescope (TMT) in the United S...

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Problems solved by technology

When using a natural star as a target for testing, in addition to being affected by the target magnitude and weather, factors such as telescope tracking error and atmospheric wavefront error will affect the accuracy of the test

The practice of deducting the influence of the atmosphere from the test results has great uncertainty, which has resulted in many telescopes being designed with high precision and poor debugging results, and the actual observation effect is naturally greatly reduced.

[0004] The 4D interferometer has the advantages of high measurement accuracy and simple operation, but it can only be detected by self-collimation. When measuring, it is necessary to place a flat mirror with the same diameter as the telescope in front of the telescope.

The 4D interferometer is more convenient for small-aperture telescope testing, but it is more difficult for large-aperture telescope testing. The main reason is that the self-collimating flat mirror used in the test has a large caliber, making it difficult to manufacture and test, and the cost is too high

[0007] 2) Sub-aperture splicing prolongs the measurement time, making environmental changes such as airflow and temperature affect the measurement results;

[0008] 3) The registration of sub-aperture and full-aperture is difficult, and the positioning accuracy of the plane mirror is high.

These studies have proved the feasibility of the sub-aperture stitching technology based on Shack Hartmann, but to a certain extent, it is still affected by the interferometer sub-aperture measurement technology. The self-collimation measurement method adopted is similar to the interferometer sub-aperture method. Also facing the technical problem of large-diameter flat mirrors

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