Testing apparatus for shape of large-aperture flat mirror

Abstract

The invention discloses a testing apparatus for the shape of a large-aperture flat mirror. The testing apparatus includes a pedestal, a rotary table, a rotary device, a pentagonal prism, a flat mirror, a grating ruler, a first autocollimator and a second autocollimator. The rotary table is arranged on the pedestal. The rotary device is fixedly connected with one end of the rotary table and is driven by the rotary device to rotate. The pentagonal prism, the flat mirror and the grating ruler are all arranged on a plane where the rotary device is away from one side of the rotary table. The firstautocollimator and the second autocollimator are arranged on one end of the rotary device and are closely adjacent to each other by being perpendicular to the rotary device. The pentagonal prism is inalignment with the first autocollimator, and the flat mirror is in alignment with the second autocollimator. The testing device is capable of testing the surface of a large-aperture flat mirror in ahorizontal direction and is high in testing accuracy.

Description

technical field [0001] The invention relates to the technical field of optical testing devices, and more specifically, to a large-diameter flat mirror-shaped testing device. Background technique [0002] Large-aperture flat mirrors have a large number of applications in space optics and astronomical optics. In order to ensure the good quality of large-aperture flat mirrors, the surface shape of large-aperture flat mirrors must be tested. [0003] There are mainly four test methods based on the test of the large-aperture plane mirror shape: direct interference test method, Ritchey-Common method, sub-aperture splicing method and pentaprism scanning method. Among them, the direct interference test method requires a high-precision large-diameter standard plane mirror, but the processing of the plane mirror is extremely difficult and the cost is high, so the direct interference test method cannot be widely used; the Ritchey-Common method requires a high-precision The cost of lar...

AI Technical Summary

Problems solved by technology

Among them, the direct interference test method requires a high-precision large-diameter standard plane mirror, but the processing of the plane mirror is extremely difficult and the cost is high, so the direct interference test method cannot be widely used; the Ritchey-Common method requires a high-precision The cost of large-diameter standard spherical mirrors is also high, and because the beam is obliquely incident on the plane mirror, it is difficult to build and adjust the optical path; the sub-aperture splicing method can avoid the use of large-diameter standard mirrors, but the error accumulation phenomenon of this method It is more serious, and the test time is long, and it is easily affected by the test environment, so the test accuracy is not very high; the pentaprism scanning method tests the surface shape of a large-diameter flat mirror by measuring the surface inclination angle, and does not need to use a large-diameter standard mirror. Low, through appropriate design algorithm and test process, can effectively suppress the influence of various major errors, and the test accuracy is high

[0004] However, the traditional large-diameter flat mirror surface shape test device based on the pentaprism scanning method can only test the vertically directed large-diameter flat mirror, which can be generally divided into two types of tests. First, the test device uses a scanning A pentaprism is used to directly measure the surface inclination angle. The test device is greatly affected by various errors and the test accuracy is low; secondly, the test device uses two pentaprisms to measure the difference of the surface inclination angle, one of which is a pentaprism A stationary reference pentaprism, the other pentaprism is a moving scanning pentaprism, this test setup can eliminate the first-order influence of the tilt error and most of the influence of the test environment, but because the two pentaprisms used have different manufacturing errors, This error leads to a lower accuracy of the final test

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