Research On The Spliced Alignment Measurement Technology Of Binary Microstructure Primary Mirror

Fresnel lens used as the optical component of binary microstructure primary mirror system is often used in the form of stitching in the large aperture optical system. Each degree of freedom stitching offset error between the sub-aperture will affect the quality of optical imaging. therefore, the study of high-precision alignment detection technology has important application value for stitching Fresnel lens. The main contents of this paper are as follows:1. Research the development of domestic and foreign alignment detection technology and its detection principles for segmented mirror and summarizes detection accuracy and detection range of the different alignment detection methods. Then it proposes plane mirror autocollimation interference detection method to achieve high precision alignment with its own characteristics of stitching Fresnel lens.2. Analyze the impact of offset error between each sub-mirror of stitching Fresnel lens on the final image quality and get different offset error tolerance with Rayleigh criterion as image quality evaluation criteria.3. Introduce plane mirror autocollimation interference detection technology to achieve high precision alignment and analyze the interference patterns with different offset error in the testing process to guide alignment. Simultaneously, it studies computer-aided alignment theory and applies it to the detection and alignment. Designs mosaic-type Fresnel lens of two sub apertures for simulation experiment, which verifies the feasibility of computer-aided alignment technology used to monitor the Fresnel lens.Finally, it proposes interference detection method using reflection hologram alignment mark for large diameter(diameter greater than 1m),and introduces its detection principle and design methods of alignment holography.4. Design mosaic-type Fresnel lens of two sub apertures, its aperture is 40 mm and focus length is 400 mm.Builds the appropriate testing experimental platform with 4D dynamic interferometer as test instrumentation, which achieves high precision alignment between the sub-mirror with its optical wavefront smaller than λ/4. Furtherly, it conducts a computer-aided alignment experiments, the alignment accuracy is in accordance with the design requirements.