The Ritchey-Chretien (RC) optical system contains an aspheric primary mirror and secondary mirror, as well as a refractive corrector lens. This flexible structure allows for a wide range of applications. The assembly process for a RC optical system differs from traditional refractive lens systems, as the aspheric reflective primary and secondary mirrors require high centering precision, which necessitates further adjustments during the assembly process. This paper discusses the assembly process for a Ø300mm RC optical system, analyzing the centering precision of the aspheric reflective primary and secondary mirrors. By adjusting the relative position of the primary and secondary mirrors based on the wavefront aberration, the final RMS wavefront aberration of the RC optical system was reduced to 0.054, and the full-field modulation transfer function (MTF) exceeded 0.68. Finally, the paper discusses the manufacturing techniques to improve the centering precision of the aspheric reflective mirrors and enhance the assembly efficiency.
Spherical and aspherical reflective optical systems are widely used in modern optical systems such as astronomical instruments and space optics due to their advantages of large field of view, absence of chromatic aberration, excellent image quality, and compact structure. However, during the assembly and adjustment process, the key is to quickly and accurately locate the curvature centers of multiple surfaces in the reflective system. Traditional methods rely on laser interferometers to monitor the entire system, which is not only cumbersome and time-consuming but also difficult to apply to the rapid adjustment of complex multi-mirror optical systems, and the required equipment is expensive. The Point Source Microscope (PSM) is a new type of alignment instrument that, based on the principle of spherical autocollimation, can quickly locate the curvature center positions of optical elements. Its simple structure and low cost make it an essential monitoring and measurement device during the assembly of complex off-axis optical systems. However, in practical applications, it has been found that the positioning accuracy of the curvature center of optical elements monitored by the PSM is influenced by many factors, with issues such as multi-degree-of-freedom compensation and sensitivity. Therefore, this paper proposes to use Measurement System Analysis (MSA) to further evaluate and analyze the positioning accuracy of the PSM to improve its accuracy.
R-C optical systems commonly used in long focal length imaging, long-distance detection fields such as aerospace and space optical communication. In this paper, the R-C optical system consists of two reflective mirrors and four correction lenses. The primary mirror adopts three sets of flexible structures for back support, which can provide a reasonable access to reduce the influence of the mirror's self-weight and thermal distortion on the mirror surface. For the high accuracy assembly, the simulation has been conducted firstly by sensitivity matrix method to figure out the sensitive components and corresponding geometrical parameters about the focal length, wavefront aberration, and energy concentration and an assembling method is proposed. Experiment is carried out to demonstrate the feasibility of the proposed calibration method, for the wavefront aberration with RMS value of center of view is 0.17λ (λ=0.6328nm), and the diameter of spot dispersion about center field of view is 12.35μm, the diameter of spot dispersion in full field of view better than 18μm can be achieved.
Optomechanical system assembly is a complex process and serves as the final stage in implementing a system, playing a crucial role in determining the performance indicators of the Optomechanical system. The performance of the Optomechanical system is mainly affected by two factors: surface shape errors of optical elements and alignment errors of components, both of which are related to the assembly process. Stress is one of the main causes of surface shape errors in optical elements. During assembly, the coupling stress can cause changes in the shape of optical elements. These changes may result in surface shape deviations from the design requirements, thereby affecting the system's performance. Alignment errors of parts and components can cause assembly errors such as misalignment, tilt, and optical spacing in the optical system. These errors can have adverse effects on the optical performance of the system. The Optomechanical system assembly errors mainly include component-level assembly errors and system-level assembly errors. To accurately analyze and estimate the assembly errors of the Optomechanical system, a small displacement torsor theory and the technique of spatial pose transformation matrix have been used to construct an error analysis model for the Optomechanical system. These models can assist engineers in predicting and controlling assembly errors, improving the performance of the Optomechanical system, and guiding the design and production of the Optomechanical system.
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