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.
The field of space imaging optics is committed to developing large field of view, large aperture, and unobstructed space optical imaging systems. The structure of optical systems has evolved from coaxial optical systems to off axis optical systems. In order to reduce the difficulty of installation and improve the efficiency of off-axis multi-reflection optical systems, the paper studies the precision installation and adjustment process method of off-axis multi-reflection optical systems on account of the principles of spherical autocollimation and spatial coordinate measurement. Establish global coordinate system based on the optical design and processing benchmark of the off-axis multi-reflection optical system, use a laser tracker and auto-collimation theodolite to accurately locate the elevation and azimuth angles of the reflector, and adjust the optical target ball to the theoretical center point position and align with PSM. Remove the target ball. If the actual center of the spherical mirror is not in the theoretical coordinate position, the position deviation and sharpness between the reflection image point and the point light source can be monitored in real-time, and the posture of the mirror can be precisely adjusted to make its reflection image point coincide with PSM. This process method can achieve high-precision and high-efficiency adjustment of the off-axis multi-reflection optical system. The assembly results show that the spatial coordinate position error between the mirrors in the off-axis multi-reflection optical system is better than 15μm through high-precision spatial coordinate positioning, reference transfer and precision measurement. The angle error is better than 30″, and the center field of view wave aberration RMS=0.034λ@632.8nm, meeting the design specifications.
With the rapid development of large field of view, large aperture and unobstructed space optical imaging system, the optical imaging system structure has developed from aspherical coaxial and off-axis free surface off-axis. Free surface is applied to multi reflective Off-axis optical system to balance the sharply increased off-axis aberration. Because the free-form surface does not have symmetry, the full free-form surface multi reflective Off-axis optical system has lost the rotational symmetry of the traditional optical system in structure, resulting in more degrees of freedom in the installation and adjustment of the full free-form surface multi reflective Off-axis optical system, the relationship between optical axes of various optical elements is complex, the system integration is more difficult, and the installation and adjustment process is difficult to monitor. Based on this, the paper proposes a precise alignment process method of the full free-form surface multi reflection Off-axis optical system. The space global coordinate system is established through the space coordinate measurement equipment, and the precise attitude of each reflector is monitored by combining the self-aligning Theodolite and cube mirror, and the reference transfer space position is measured by using the self-aligning microscope and the measurement target ball. he engineering project verification shows that this assembly and adjustment process method realizes the unification of the design, processing and assembly and adjustment benchmark of the full free-form surface multi reflection Off-axis optical system, has strong operability, reduces the difficulty of assembly and integration, and the comprehensive measurement accuracy is better than 0.01 mm. The wave aberration RMS of the final refrigeration relay long wave infrared camera system is better than 0.45 λ @ 632.8nm, meeting the design specifications.
The axial compact fixing position of the optical element is mainly carried out in the form of tightening the compression ring in the optical lens assembly process. Most of the existing compression ring tightening methods use forceps and other general press ring tightening tools, the degree of tightening of the pressure ring when used mainly depends on the experience and feel of the assembler, cannot quantify the compression ring tightening torque. In order to solve the above technical problems, the research topic of optical lens compression moment quantification process technology is proposed. Based on the principle of strain sensor, a special digital explicit compression moment device was successfully developed. According to the mass production project of XX optical lenses, the test scheme of the tightening moment of each lens press is designed, and multiple compression ring tightening tests are carried out using a special digital explicit compression moment device, and the corresponding change relationship between the compression moment range of the whole lens and the lens surface type (RMS) is summarized. According to GB/T 34516-2017 "Spacecraft Vibration Test Method", the random vibration test method in the vertical direction of "sweep-vibration-sweep frequency" was used to complete the compression moment tightening performance and reliability verification. The test results are shown that the characteristic sweep curve of the optical lens before and after the vibration has not changed, the modality has always remained stable, the lens shape (RMS) remains unchanged, the optical lens is not loosened, the digital explicit compression moment device developed meets the technical requirements of the optical lens assembly process, and the compression ring tightening torque is quantified, which further improves the assembly quality reliability and assembly efficiency.
Aiming at the problem of abnormal sound of lens caused by incomplete tightening of pressure coil after optical lens installation, this paper presents a method for calculating and verifying the tightening moment of pressure coil. According to the mechanical dimension of the screw thread of the pressing ring, the mechanical properties of the pressing ring of the mirror tube and the optimal number of turning rings were calculated and analyzed. In order to meet the practical application requirements, the tightening moment of the pressure coil obtained by the solution was brought into the 3D model for simulation, and the finite element modeling analysis of the tightening moment of the pressure coil of the optical lens was completed, so as to further solve the displacement variation of the lens group. Finally, the above analysis results were quantified by torque wrenches, and random vibration was carried out at one third of the order of acceptance level vibration test conditions, so as to complete the bottom analysis and verify the tightening torque of the screw ring under different ratios of XM-31 adhesive and vulcanizing agent. The experimental results show that the characteristic sweep curve of the optical lens does not change before and after the vibration, the mode of the optical lens remains stable all the time, and the data modal analysis results are consistent with the actual situation.
The laser transceiver contains a lot of complex optical refractors. The laser signal is emitted from the laser, transmitted through the optical fiber and the transceiver, and entered into the air after multiple splitting, reflection and expansion, so as to exchange information with the outside world. The direction of the laser axis changes with the motion of the two-dimensional turntable. In the process of coupling between the laser fiber and the transceiver, the parallel light generated by the receiving and transmitting collimator should be meet the requirements of consistent divergence angel, parallelism and coincidence at the light outlet of the device. In this paper, the method optical axis consistency detection and adjustment in the process of laser coupling and turntable integration is studied, the device for determining the optical axis reference is designed. By means of precise adjustment, the optical axis and the reference device coincide precisely, and the detection and debugging of optical axis paralleling and coincidence are realized.
From the special structure, processing technology and function of Fery prism in spectral imager, and the structural design features of a certain research spectral imager project, an assembly measurement method based on CMM, PSM and high precision rotating device is proposed, which combines the principles of space measurement, point source collimation and 3D mathematical modeling, the on-line inspection and alignment technology of Fery prism assembly are studied. Firstly, the key parameters of a single curved prism, such as curvature radius of surface, spherical coordinates, deflection angle of optical axis and off-axis are measured by CMM. Secondly, the Fery prism assembly is assembled by CMM, PSM and high precision rotating device. The space coordinates between the components are measured by CMM, and the position of the Spherical Center and the deflection angle are precisely determined by point source microscope. Finally, the actual assembly effect of the Fery Prism Assembly is reappeared through the data processing of the computer software, and the directional offset between the Fery prism assembly and the theoretical model is given, the precision assembly of Fery prism aseembly is completed by azimuth rotation and trimming mat processing. It provides a new technology method for on-line precision assembly of Fery prism module in Spectral Imager, which has strong operability and high measurement precision, and is suitable for precision detection and assembly of Fery prism module of different sizes.
On the basis of optical theory, the mathematical model of axisymmetric high-order aspherical curve and the curve characteristic parameters related to the locus of aspherical surface are summarized. The non-contact precise measurement and correction of the central deviation of axisymmetric high-order aspherical lens based on autocollimated centering principle and spectral confocal displacement sensing technology are introduced. The methods of measuring the center deviation of aspheric lens with concave and convex surfaces are given. The aspheric measuring device of Trioptics double optical path center deviation measuring instrument is used to measure the axisymmetric high-order aspheric lens, Through several measurements and modifications, the final results meet the requirements of the whole optical system for the optical axis deviation of the axisymmetric high-order aspheric lens. The technology of measuring and correcting the center deviation of high-order aspheric lens with axial symmetry introduced in the paper has high non-contact measuring accuracy, which can guide the adjustment amount and position direction of the coincidence of the axis of symmetry and the axis of mechanical rotation of aspheric lens. It can be widely used in the process of on-line processing, testing and systematic adjustment of aspheric lens and aspheric mirror with different apertures. While ensuring the accuracy of aspheric surface, it can improve the quality of finish grinding process, save a lot of time for polishing process, and play a guiding role in its processing and manufacturing process and high-precision system installation, so as to greatly improve the processing efficiency of axisymmetric high-order aspheric surface and the final optical system installation and adjustment accuracy.
A method to measurement of optical axis eccentricity and fitting about the aspheric mirror with the high-precision three-coordinate measuring machine(CMM) is presented. By establishing 2d/3d measurement coordinate system, The axis of fitting of the cylinder is selected according to the machining and assembly reference of aspheric mirror, Generating a number of concentric circles automatic measurement strategies, And make the points on each equal circumference, The probe head of the CMM is sampled on the surface of the measured aspheric mirror according to the measured strategy path to obtain the point coordinates of the distance of the reference axis, the measured surface is fitted to obtain the eccentricity of the aspheric mirror optical axis. Hyperboloid concave mirror to make use of the proposed method in the practical testing, the results show the actual processing of eccentricity is 0.0190mm, the standard deviation of 3.6×10-4mm, to meet the requirements of the design of eccentricity is less than or equal to 0.02mm.And testing the high precision centering lathe cutting machine frame fixed axis aspheric reflector components, the data indicators meet the requirements of assembly process. The accuracy of this method is high, and the traditional measuring method is easy to be affected by the precision of the tooling and easy to scratch the mirror. With large work surface, large caliber, back light weight loss (special-shaped structure) of aspheric mirrors optical axis eccentricity detection, not only suitable for different aperture aspheric mirrors the processing quality of qualified determination, but also in the machining, high precision of aspheric mirrors system with adjustable guiding role and effectively promote R-C spherical reflector optical system assembly accuracy and efficiency.
KEYWORDS: Photovoltaics, Near field, Wavefronts, Laser systems engineering, Adaptive optics, Near field optics, Mirrors, Modulation, Reflectors, Wavefront sensors
The paper presents a method based on the principle of auto-collimating to assemble the large-aperture laser beam reduction system. The method solves the problem of using fiber laser, plane mirror and Hartman wavefront sensor to realize the precision assembling of the large-aperture laser beam reduction system in the absence of large-diameter standard light source. Using the method, The large-aperture laser beam reduction system is successfully assembled in the big science project. And the technical index of the system is tested and the uncertainty is analyzed. The near field modulation degree is 1.03, the contrast is 0.025, the wavefront distortion is 0.476λ(λ=1053nm), and the system meets the requirements of the engineering index.
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.