Secondary Surface Mirror Lucky Method Of Test Sensitivity And Accuracy Analysis

The paper, firstly, introduces a survey of the development and current situation of the Ronchi test for the conicoid mirrors at the state and overseas, then gives the geometrical and physical principle, as well as the relative theories of Ronchi ruling and classical Ronchi test sensitivity. In order to research the effects on Ronchi test result of conicoid mirrors caused by different types of ruling periods and other relative factors, a new kind of method is advanced to evaluate the sensitivity of Ronchi test, which can be defined as the capability of testing the surface errors for a ruling period. Given the Ronchi ruling with certain period, the smaller the slope error can be tested, the higher the sensitivity value will be.The formula of test sensitivity is calculated and concluded by ray tracing method based on the geometrical principle of Ronchi test after discussing the relationship between the mirror deviation and Ronchi ruling period. Applying the formula to parabolic, hyperbolic and ellipsoidal mirrors when giving the corresponding parameters of mirror and the test arrangement for ray, a conclusion can be drawed that, the sensitivity of the test decreased with the period space of Ronchi ruling, the aperture radius separately.The paper also gives a research to the accuracy analysis of the Ronchi test, which aims at getting the quantitative value of mirror deviation under a Ronchi ruling with certain period. The rightness and reliability of the new developed definition of Ronchi test sensitivity above can be verified by calculating the Ronchi test accuracy of all kinds of conicoid mirrors. Besids, a software relating with the sensitivity and accuracy analysis of Ronchi test has been made, which can be independent from MATLAB environment.The paper gives a particular and detailed study to the Ronchi test sensitivity, and analyzed all the possible relative parameters with it. The paper provides a theoretical reference and an important instruction to the following practice of applying Ronchi test to the conicoid mirrors, especially aspherical mirrors with big aperture radius.