Infrared detection technology is getting more and more attention, with the rapid development of infrared remote sensing application. Among them, low temperature infrared spectroscopy detection technology is an important development direction in the future. Infrared detection technology is a kind of target detection technology, using the infrared radiation characteristics of substances to different wavelengths. Infrared spectrometer is an important instrument to realize infrared detection technology. This type of spectrometer has been popularized and applied. The imaging spectrometer can reflect the spatial information and spectral characteristics of the observation target. With the improvement of spectral imaging resolution, the signal-to-noise ratio of imaging system is required to increase, which is the technical difficulty of low-temperature infrared spectroscopy. At present, noise reduction through low temperature is the main method. Therefore, infrared detection technology to work in a lower temperature direction. Furthermore, it promotes the progress of low temperature infrared spectroscopy technology. This paper summarizes and compares the development status of low temperature infrared spectrum detection technology. Thus, the key technology of low temperature detection spectrum is extracted. The low temperature infrared detection technology is classified according to the development status of low temperature infrared optics, low temperature support technology and low temperature refrigeration technology. Summarize the shortcomings of domestic existing technology and look forward to the future development direction.
To address the problem that bonding can lead to a reduction in the surface shape precision of a space-bound mirror, relationships between mirror deformation, thermal stress, and curing shrinkage stress were studied, and a bonding microstress design route was proposed. The thermal stress and thermal deformation introduced by thermal expansion mismatch were eliminated through an athermal adhesive layer thickness design. The relationship between mirror deformation and the curing shrinkage of the adhesive layer was derived completely, and structural optimization measures for releasing the curing stress of the adhesive layer are given. Bonding stress analysis was conducted based on the equivalent thermal deformation method, and an optimal structure meeting the design requirements was obtained. Finally, bonding of the mirror assembly was completed via this route, and the measured surface shape precision was stable at 0.0225λ. The theoretical analysis and experimental study demonstrate that this bonding design method can predict the bonding stress in the assembly process, making the follow-up bonding result controllable. These results should provide an excellent reference for the design and high-precision integration of large-aperture mirrors.
In order to solve the problems of long manufacturing cycle and high processing cost of mirrors in reflective optical systems of space cameras, a method for manufacturing metal mirrors based on additive manufacturing process is proposed. This paper designs an open honeycomb structure on the mirror backplane, mirror blank is prepared by additive manufacturing technology. Preliminary improvement of surface quality with rough machining and diamond turning. Then, a high-precision mirror surface is obtained through surface modification and secondary diamond turning. The diameter of the prepared mirror is 110mm, mass reduction rate of 70% and surface shape accuracy is better than λ /15 RMS( λ =632.8nm).The results show that the metal mirror prepared by this process can meet the requirements of high-precision reflective optical systems. The research work in this article can provide technical reference for the application of additive manufacturing technology in the field of optics. It has important reference and guiding significance for the research and application of related fields.
With the increasing demand of infrared detection, the infrared cold optical technology has developed rapidly in recent decades. The low temperature deformation of infrared optical elements is one of the key factors restricting the development of infrared cold optical technology. The processing and assembly of optical subassemblies and support structures are carried out at room temperature and pressure, while the actual working environment of infrared system is relatively low temperature environment, which can vary by 200 degrees Kelvin or more. Therefore, the temperature adaptability of the support structure is strictly required. The optimal design flexible support of the 70mm diameter single crystal lens made by germanium was carried out to ensure that the component surface shape reached (1/6) λ and the natural frequency was above 200HZ at 100K low temperature in this paper. At the same time, the ISIGHT integrated optimization method was used to optimize the flexible support structure. The multi-objective integrated optimization of key dimensions of flexible support was completed, aiming at maximizing the fundamental frequency of the system and minimizing the lens surface shape errors. Finally, the optimal size was selected to complete the flexible structure design. In this paper, an adaptive flexible support structure for cold optical lens with three layers of stress release was designed by multi-objective integrated optimization method. Meanwhile, its performance was verified by low temperature tests. The results verified the reliability and the feasibility of the structure design and analysis.
The research on optical-mechanical system based on additive manufacturing is based on additive manufacturing, diamond turning, high-precision magnetorheological polishing, surface modification technology, internal lattice structure topology optimization and so on. It can overcome the problems of adhesive use and material matching in the traditional structure design, greatly reduce the difficulty of assembly and thermal control, and realize the lightweight design of internal structure that can not be realized by traditional processing methods. In addition, because the mirror body and its supporting structure are made of same metal materials and integrated, the strength and stiffness are greatly improved compared with the traditional design method. This paper summarizes the development status and technical parameters of additive manufacturing opto-mechanical system at home and abroad. The research progress of surface modification technology by domestic and foreign scholars was focused and the post-processing process and core technologies of the optical-mechanical system were described.
To ensure the high surface accuracy and high thermal stability of space mirror, a lightweight design for the Φ514mm ULE primary mirror of a space remote sensor and flexible support structure with three-point was carried out. By further optimizing the parameters of the flexible supporting structure, the requirements of the optical index were met. The finite element model of the mirror assembly was established, and the static and dynamic characteristics of the assembly were analyzed. The results showed that the surface shape accuracy (RMS) of the mirror assembly is better than 8 nm under a load case of 1g gravity when the optical axis is level, and the first-order natural frequency of the component is 254 Hz. Finally, a mechanical test was carried out on the mirror assembly. The test results showed that the first-order frequencies of the three directions of the mirror assembly are all greater than 100 Hz , the error between the test data and the finite element analysis results does not exceed 10%. Analysis and test results showed that, the reasonable support structure design can effectively lower the change of the mirror surface shape caused by assembly stress and thermal stress, and has good dynamic performance. It is verified that the mirror and its supporting structure designed in this paper are reasonable, which provides reference and ideas for the design of flexible supporting structure of similar space mirror.
To minimize the assembly stress and thermal stress introduced by the support structure, and ensure the high surface accuracy and high thermal stability of space mirror. An ultra-lightweight design of secondary mirror was carried out for some space remote sensor, and three tangential bipods were used for quasi-kinematic support. Firstly, the design principle of quasi-kinematic support structure was investigated, and advantages of bipod kinematic support were analyzed from the angle of degree of freedom decoupling. Based on structure designed above, the finite element model was established. Taking surface accuracy of the mirror as optimization objectives, the integrated optimization method was adopted to extract the structural parameters with high sensitivity on the surface accuracy in the flexible support structure, and parameters optimization design was carried out. Finally, the static and dynamic characteristics of the optimized mirror assembly were analyzed. The analysis results showed that the surface shape accuracy (RMS) of the mirror assembly is better than 1 nm under a load case of 1g gravity when the optical axis is level. Surface accuracy (RMS) is better than 2 nm under the load case of 4℃ uniform temperature rise. The first-order natural frequency of the secondary mirror assembly is 587 Hz. The optimized mirror support structure can well unload the additional deformation caused by the support structure, and has good dynamic stiffness, which verifies that the designed mirror and its support structure are reasonable, and the optimization design method is reliable. This paper provides a reference and idea for the design of flexible support structure of space mirror.
The influence of adhesive bonding and curing on the accuracy of mirror surface shape was analyzed to realize low-stress assembly of large aperture mirror. Firstly, based on Hooke's law, a curing shrinkage stress equation was deduced, taking deformation of the mirror and support structure into account under the boundary condition of continuous edge bond, and key parameters effecting mirror deformation were obtained. Secondly, for a 514mm ULE spectrometer primary mirror with an inserts structure mosaiced and bonded on mirror-back, an equivalent linear expansion coefficient method was used for finite element modeling. The shrinkage stress at the bond edge of mirror and the mirror surface shape were analyzed. It’s found that adhesive shrinkage has a significant effect on the mirror surface shape. Finally, the inserts structure of mirror assembly was optimized. In contrast to the non-optimum structure, the average stress of adhesive surface caused by adhesive curing shrinkage reduced from 0.28MPa to 0.18MPa, and the mirror surface shape (Root Mean Square, RMS) reduced from 0.029λ to 0.017λ. Finite element analysis results of the mirror assembly were given at last, surface shape accuracy (RMS) of mirror is 0.012λ under a load case of 1g gravity, and the first-order natural frequency of the component is 216 Hz. The obtained results showed that a suitable optimized support structure can effectively relieve adhesive curing stress, and also satisfy the design requirements for both the static and dynamic stiffness.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.