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Littérature scientifique sur le sujet « F-θ lens »

Auteur : Grafiati

Publié le 25 janvier 2025

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Articles de revues sur le sujet "F-θ lens"

Huang, Kuang-Lung, Mei Chu, Cheng-Huan Chen, Yu-Chung Lin, Min-Kai Lee et Sung-Ho Liu. « Enlarging lens design with f-Θ lens for real time laser lithography inspections ». Optical Review 18, n^o 1 (janvier 2011) : 72–75. http://dx.doi.org/10.1007/s10043-011-0034-y.

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Rez, Peter. « Analytic integration of contrast transfer functions ». Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988) : 822–23. http://dx.doi.org/10.1017/s042482010010617x.

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In high resolution microscopy the image amplitude is given by the convolution of the specimen exit surface wave function and the microscope objective lens transfer function. This is usually done by multiplying the wave function and the transfer function in reciprocal space and integrating over the effective aperture. For very thin specimens the scattering can be represented by a weak phase object and the amplitude observed in the image plane is1where fe (Θ) is the electron scattering factor, r is a postition variable, Θ a scattering angle and x(Θ) the lens transfer function. x(Θ) is given by2where Cs is the objective lens spherical aberration coefficient, the wavelength, and f the defocus.We shall consider one dimensional scattering that might arise from a cross sectional specimen containing disordered planes of a heavy element stacked in a regular sequence among planes of lighter elements. In a direction parallel to the disordered planes there will be a continuous distribution of scattering angle.

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Yang, Su, An Zhi-yong, Li Qi et Xu Miao. « Optical design of wide-angle large-relative-aperture f-θ lens ». Journal of Applied Optics 36, n^o 3 (2015) : 376–80. http://dx.doi.org/10.5768/jao201536.0301007.

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Ning, Chen Wei, Cao Jian Zhong, Yang Hong Tao, Zhang Jian, Fan Zhe Yuan, Wu Li, Zhang Hui et Lei Yang Jie. « Target Optimization Design of Cam Curve in Zoom System ». Key Engineering Materials 552 (mai 2013) : 44–51. http://dx.doi.org/10.4028/www.scientific.net/kem.552.44.

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Zoom lens has been widely applied in all kinds of fields, and its cam optimization is the key to actualizing the performance of its optical design and the zooming process, while the smoothness and speediness of zooming movement must be considered for military and civilian use. With the incremental use of environmental requirements, it puts forward higher requests to the cam performance of lens. In order to guarantee that the cam has good stiffness in the case of vibration and shock environment, in the process of cam design, it not only requires curve optimal, but also needs to consider influence on the performance which is caused by reduced cam stiffness of the zoom system. A fine curve can ensure that the cam pressure angle α is smaller, and to ensure the cam follower maintains the uniform velocity and smaller acceleration in zooming process, and make the zoom system produce little impact, and whole zooming process smooth and fluent, it can reduce the zoom systems driving moment M, and can ensure the stability imaging of the zoom system. Good cam stiffness K can make the zoom lens have good stability in vibration environment, and make sure that the image quality. M and K respectively up to the pressure angle α of zoom curve and the rotation angle θ of zoom curve in cam. In the new cam design process, considering the whole influence on the performance that is caused by K and M to cam, we construct the function expressions K = f (α, θ) and M = f (α, θ), and then, build target optimization function with K and M, optimize the relationship between pressure angle α of zoom curve and rotation angle θ, looking for the optimal value for the stiffness K and the cam system driving moment M , and improve overall performance of the zoom cam .

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Yuanyuan, LI, WANG Chunyan et WANG Zhiqiang. « F-θ lens design for high-precision semiconductor laser marking machine ». Journal of Applied Optics 41, n^o 1 (2020) : 202–8. http://dx.doi.org/10.5768/jao202041.0107003.

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May, Karl Henrik, Shiva Mohammadzadeh, Andreas Keil, Georg von Freymann et Fabian Friederich. « Coherent Off-Axis Terahertz Tomography with a Multi-Channel Array and f-theta Optics ». Sensors 24, n^o 2 (15 janvier 2024) : 529. http://dx.doi.org/10.3390/s24020529.

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Terahertz tomography is a promising method among non-destructive inspection techniques to detect faults and defects in dielectric samples. Recently, image quality was improved significantly through the incorporation of a priori information and off-axis data. However, this improvement has come at the cost of increased measurement time. To aim toward industrial applications, it is therefore necessary to speed up the measurement by parallelizing the data acquisition employing multi-channel setups. In this work, we present two tomographic frequency-modulated continuous wave (FMCW) systems working at a bandwidth of 230–320 GHz, equipped with an eight-channel detector array, and we compare their imaging results with those of a single-pixel setup. While in the first system the additional channels are used exclusively to detect radiation refracted by the sample, the second system features an f-θ lens, focusing the beam at different positions on its flat focal plane, and thus utilizing the whole detector array directly. The usage of the f-θ lens in combination with a scanning mirror eliminates the necessity of the formerly used slow translation of a single-pixel transmitter. This opens up the potential for a significant increase in acquisition speed, in our case by a factor of four to five, respectively.

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Tien, Chuen-Lin, Chun-Yu Chiang et Wen-Shing Sun. « Design of a Miniaturized Wide-Angle Fisheye Lens Based on Deep Learning and Optimization Techniques ». Micromachines 13, n^o 9 (27 août 2022) : 1409. http://dx.doi.org/10.3390/mi13091409.

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This paper presents the optimization design of a miniaturized five-element wide-angle fisheye lens using a deep learning algorithm. Zemax optical design software was used to simulate and optimize the wide-angle fisheye lens. A deep learning algorithm helped to find the best combination of different lens materials. We first used six lens elements as an initial configuration to design miniaturized wide-angle fisheye lenses using the optimization process. The optical system components were gradually decreased to five lens elements. Both OKP4HT and polymethyl methacrylate (PMMA) plastic aspheric lenses were selected to replace the second spherical glass lens in the original design. We propose two types of wide-angle fisheye lens designs with four spherical lenses and one aspheric lens. The results for these designs indicated a viewing angle of 174°, a total length of less than 15 mm, a spot size of less than 6 μm, lateral color within ±1 μm, field curvature within ±0.02 mm, and F-θ distortion of ±3.5%. In addition, the MTF value was larger than 0.4 at the spatial frequency of 100 cycles/mm.

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Volyar, Alexander, Eugeny Abramochkin, Yana Akimova et Mikhail Bretsko. « Astigmatic-Invariant Structured Singular Beams ». Photonics 9, n^o 11 (8 novembre 2022) : 842. http://dx.doi.org/10.3390/photonics9110842.

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We investigate the transformation of structured Laguerre–Gaussian (sLG) beams after passing through a cylindrical lens. The resulting beam, ab astigmatic structured Laguerre–Gaussian (asLG) beam, depends on quantum numbers (n,ℓ) and three parameters. Two of them are control parameters of the initial sLG beam, the amplitude ϵ and phase θ. The third one is the ratio of the Rayleigh length z0 and the focal length f of the cylindrical lens. It was theoretically revealed and experimentally confirmed that the asLG beam keeps the intensity shape of the initial sLG beam when the parameters satisfy simple conditions: ϵ is unity and the tangent of the phase parameter θ/2 is equal to the above ratio. We also found sharp bursts and dips of the orbital angular momentum (OAM) in the asLG beams in the vicinity of the point where the OAM turns to zero. The heights and depths of these bursts and dips significantly exceed the OAM maximum and minimum values of the initial sLG beam and are controlled by the radial number n.

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Wang Chunhui, 王春晖, 季一勤 Ji Yiqin, 高龙 Gao Long, 李彦超 Li Yanchao et 曲杨 Qu Yang. « Optical Design of Large Working Area f-θ Scanning Lens for 2 μm Laser Heterodyne Interferometry System ». Chinese Journal of Lasers 38, n^o 12 (2011) : 1216002. http://dx.doi.org/10.3788/cjl201138.1216002.

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Pang, Yajun, Kai Zhang, Zhenxu Bai, Youchun Sun et Meiling Yao. « Design Study of a Large-Angle Optical Scanning System for MEMS LIDAR ». Applied Sciences 12, n^o 3 (25 janvier 2022) : 1283. http://dx.doi.org/10.3390/app12031283.

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MEMS-based LIDAR has the advantages of fast-scanning, simple structure, small volume, and light weight, which make it a hot topic for 3D imaging. In order to overcome the limited scanning angle of the current MEMS mirrors, a large angle MEMS-based optical scanning system was designed using telephoto structure. In this design an f-θ lens group is used for flat field scanning and a symmetrical cemented lens group is used for angle expansion. The principle of this system is discussed in detail and an optical design is implemented by ZEMAX software. The designed system realized a scanning angle as large as 57° and is in excellent linear relation with the tilt angle of the MEMS mirror. At the target distance of 100 m, the maximum RMS radius of the light spot is only 7 cm. This optical scanning system shows a significant application potentiality for 3D imaging LIDAR.

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Thèses sur le sujet "F-θ lens"

Carré, Barnabé. « Développement applicatif sur l’intégrabilité de systèmes d’imageries et de contrôle d’épaisseur par le biais de radar FMCW dans le domaine des ondes Terahertz ». Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0335.

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Afin de stimuler l'intérêt des industriels pour les systèmes térahertz dans le domaine du contrôle non destructif, ce manuscrit présente diverses méthodes et techniques d'amélioration des performances d'imagerie et de mesure d'épaisseur des capteurs radar sub-THz FMCW (Frequency Modulated Continuous Wave). Les approches d'imagerie focalisée sont restreintes par la diffraction et impliquent un compromis entre résolution latérale et profondeur de champ .La technique d'imagerie SAR (Synthetic Aperture Radar) permet de surmonter ces limites. Dans ce cadre, une nouvelle approche algorithmique est proposée, améliorant de manière significative la résolution latérale en la triplant par rapport aux systèmes d'imagerie focalisée classiques. De plus, la technique SAR est testée sur des objets spécifiques pertinents pour l'imagerie non destructive.Les systèmes d'acquisition point par point sont souvent limités en vitesse de mesure en raison des contraintes liées aux vecteurs de translation, soumis à des inerties trop élevées.Pour répondre à cette problématique, un système d'imagerie ultrarapide a été développé. Celui-ci intègre un miroir polygonal rotatif qui dévie le faisceau radar et le dirige vers une lentille f-theta télécentrique, capable de focaliser le faisceau sur un plan. Cette lentille, dotée d'une ouverture numérique de 0,28, surpasse celles rapportées dans la littérature.En outre, les capteurs radar FMCW sub-THz ne se limitent pas à l'imagerie non destructive, mais permettent également une mesure précise de l'épaisseur des matériaux. Cependant, ces mesures sont traditionnellement limitées par la résolution longitudinale de l'unité radar.Cette étude propose un algorithme innovant, combiné à une nouvelle approche par algorithme génétique, qui permet de dépasser cette limite en mesurant des épaisseurs cinq fois plus fines que la résolution longitudinale dans l'air du capteur
In order to encourage industrial interest in terahertz systems for non-destructive testing, this manuscript features various methods and techniques for improving the imaging and thickness measurement performance of sub-THz FMCW (Frequency Modulated Continuous Wave) radar sensors.Focused imaging approaches are restricted by diffraction and involve a compromise between lateral resolution and depth of field. The SAR (Synthetic Aperture Radar) imaging technique overcomes these limitations. In this context, a new algorithmic approach is proposed, significantly improving lateral resolution by a factor of three compared with conventional focused imaging systems. In addition, the SAR technique is tested on specific objects relevant to non-destructive imaging. Point-by-point acquisition systems are often limited in measurement speed due to the constraints associated with translation vectors, which are subject to excessively high inertias.To tackle this problem, an ultra-fast imaging system has been developed. This incorporates a rotating polygonal mirror which deflects the radar beam and directs it onto a telecentric f-theta lens, which focuses the beam onto a plane. This lens, with a numerical aperture of 0.28, outperforms those reported in the literature. In addition, sub-THz FMCW radar transceivers are not limited to non-destructive imaging, but also enable precise measurement of material thickness. However, these measurements are usually limited by the longitudinal resolution of the radar unit. This study proposes an innovative algorithm, combined with a new genetic algorithm approach, which overcomes this limitation by measuring thicknesses five times thinner than the longitudinal resolution in the air of the sensor

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Chen, Chien Chuan, et 陳建銓. « The studies of the f-θ lens design for PCB CO2 laser drilling machine ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/72742398196954358242.

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碩士
國立彰化師範大學
機電工程學系
93
The purpose of this thesis is to analyze and design the f-θ lens for the PCB CO2 laser drilling machine by using of ZEMAX optical software. Because the focusing behavior of the general focus lens is non-linear, the velocities of the spots with constant scanning angular speeds are not constant. For this reason, there are several aberrations in the image plane such as astigmatism, field curvature and distortion. Due to these errors, the energy of the spots and the quality of the drilled holes will be decreased. However, the linear focus lens, called f-θ lens, behaves linearly. This kind of lens is able to increase the quality of laser drilled holes. Therefore, it is an important component in a laser scanning system. In order to achieve a linear behavior, f-θ lens should be designed with negative distortion. In this paper, we measure the curvature and thickness of a single f-θ lens and discuss the performance of it. Then, we design three types of f-θ lenses which use two, three and five piece lenses. The scan area of these lenses is 100mm x100mm, and the aberration can be controlled. Finally, the design of the lens mount is also presented in this paper, the effect of the tolerances on the system is discussed with the analysis of the sensitivity and the inverse sensitivity.

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Actes de conférences sur le sujet "F-θ lens"

Ding, Li, et Bin Shan. « Replacing f-θ lens with normal lens by curve fitting ». Dans Photonics China '98, sous la direction de Qiming Xin et Robert E. Parks. SPIE, 1998. http://dx.doi.org/10.1117/12.318331.

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McIntyre, Kevin J., et G. Michael Morris. « Diffractive Optics Technology for F-Θ Scan Lenses ». Dans Diffractive Optics and Micro-Optics. Washington, D.C. : Optica Publishing Group, 1996. http://dx.doi.org/10.1364/domo.1996.dtua.4.

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A variety of optical systems utilize F-θ lenses to focus a scanned laser beam to a small spot. Typical applications include laser printing and laser machining. Since scan lenses usually operate at discrete laser wavelengths, diffractive optical components can be incorporated into these designs without the efficiency losses normally associated with broadband applications. This paper will examine the use of diffractive optical elements in F-θ scan lens design. A discussion of some basic design principles is provided. This is followed by a comparison between a refractive system and a hybrid system which illustrates how diffractive optics can significantly enhance the performance of F-θ scan lenses.

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Kim, Mugeon, Eui su Lee, Dong Woo Park, IL-Min Lee et Kyung Hyun Park. « Hexagonal polygon mirror based terahertz imaging system by using telecentric f-Θ lens ». Dans 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz). IEEE, 2019. http://dx.doi.org/10.1109/irmmw-thz.2019.8873863.

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Moon, Kiwon, Il-Min Lee, Eui Su Lee et Kyung Hyun Park. « Photonics-based multi-spectral THz imaging using a dual-mode laser and a telecentric f-θ lens ». Dans CLEO : Science and Innovations. Washington, D.C. : OSA, 2019. http://dx.doi.org/10.1364/cleo_si.2019.stu3f.7.

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McIntyre, Kevin J., G. Michael Morris, Susan Dunn, Karen Rumsey et Ken Ossman. « Laser printer scan lens with diffractive optics ». Dans Diffractive Optics and Micro-Optics. Washington, D.C. : Optica Publishing Group, 1998. http://dx.doi.org/10.1364/domo.1998.jthb.3.

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A scan lens for a laser printer system consists of an F-θ lens and a scanning element, typically a polygon mirror. Due to mechanical wobble and facet-to-facet misalignment, a polygon mirror tends to steer the focused beam out of the intended scan line and therefore requires some form of optical compensation. The most common method1 makes use of anamorphic optical elements. Traditionally, lenses based on this approach contain either a toroidal surface or a reflective cylindrical field lens, both of which are relatively expensive. It is possible to use a diffractive surface to replace the need for either of these surface types. Non-toroidal hybrid scan lenses have been discussed previously2,3. These designs were limited to rotationally-symmetric geometries and therefore could not be used with polygon mirrors. This paper discusses the design, fabrication, and testing of a prototype diffractive scan lens for a 600 dpi laser printer system.

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Frieden, B. Roy. « Fisher information and error complimentarity ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.fl3.

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The Cramer-Rao (CR) inequality e2I ≥ 1 represents complimentarity between (i) the size of mean-squares error e2 in estimation of a parameter θ from an observation y where y = θ + x, and (ii) the Fisher information I due to pdf p(x). In application to quantum mechanics, θ is the classical position of a particle, and I becomes the mean-squares momentum spread for the particle. Thus, the CR inequality becomes the Heisenberg uncertainty principle. The latter is, then, but one example of a general principle of error complimentarity. As applied to optical diffraction, θ is now the unknown centroid of a diffraction pattern. Here the CR inequality becomes e2z2 ≥ (λf/4π)2, where z2 is the mean-squares photon position in the lens pupil, λ is the light wavelength, and f is the focal length. Interestingly, here the uncertainty product can be made arbitrarily small. Another use is in the case of a nonideal gas kept at a constant temperature T. The gas is inside a container of unknown drift velocity θ. If p(x) defines the probability law on velocity x for particles of the gas, the CR inequality attains a minimum for the uncertainty product e2I when p(x) is Gaussian, i.e., when p(x) is a Boltzmann law. This describes the ideal gas scenario and gives it a new significance.

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Ma, Hsiao-Kang, Jyun-Sheng Wang et Ya-Ting Chang. « Study of a Pseudo Bipolar Design for a Piezoelectric Proton Exchange Membrane Fuel Cell With Nozzle and Diffuser ». Dans ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2010. http://dx.doi.org/10.1115/fuelcell2010-33061.

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Previous studies of a piezoelectric proton exchange membrane fuel cell with nozzle and diffuser (PZT-PEMFC-ND) have shown that a PZT device could solve flooding problems and improve cell performance. The results also indicated that the rectification efficiency (γ) of the diffuser elements, the PZT vibrating frequency (f), and the displaced volume per stroke (ΔV) affected the flow rate of the PZT device. The rectification efficiency of the diffuser elements, which is an indicator of the preferential direction, depends on the geometrical parameters (AR and θ) and the Reynolds number. In this study, an innovative design for a PZT-PEMFC-ND bi-cell with pseudo bipolar electrodes was developed to achieve a higher power in the stack design to solve water flooding problems and improve cell performance. This new design, with a reaction area of 8 cm2, contains two cells with two outside anodes and two inside cathodes that share a common PZT vibrating device for pumping air flow. The influence of the varying aspect ratio (AR) of the diffuser elements on the unit cell flow rate were investigated using a three-dimensional transitional model. The results show that a proper AR value of 11.25 for the diffuser with a smaller θ of 5° could ensure a smoother intake of the air and thus better cell performance. A lower AR value of 5.63 resulted in smaller actuation pressure inside the chamber, and thus the produced water could not be pumped out. However, a larger AR of 16.88 induced a blocking phenomenon inside the diffuser element, and thus less air was sucked into the cathode chamber. The performance of the PZT-PEMFC-ND bi-cell could be 1.6 times greater than that of the single cell. This performance may be influenced by the phase difference of the operating modes.

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