Добірка наукової літератури з теми "Ellipsoidal reflector"

Angular measurements in optics of biological tissues are used for different applied spectroscopic task for roughness surface control, define of refractive index and for research of optical properties. Purpose of the research is investigation of the reflectance of biologic tissues by the ellipsoidal reflector method under the variable angle of the incident radiation.The research investigates functional features of improved photometry method by ellipsoidal reflectors. The photometric setup with mirror ellipsoid of revolution in reflected light was developed. Theoretical foundations of the design of an ellipsoidal reflector with a specific slot to ensure the input of laser radiation into the object area were presented. Analytical solution for calculating the angles range of incident radiation depending on the eccentricity and focal parameter of the ellipsoid are obtained. Also created the scheme of image processing at angular photometry by ellipsoidal reflector.The research represents results of experimental series for samples of muscle tissues at wavelengths 405 nm, 532 nm, 650 nm. During experiment there were received photometric images on the equipment with such parameters: laser beam incident angles range 12.5–62.5°, ellipsoidal reflector eccentricity 0.6, focal parameter 18 mm, slot width 8 mm.The nature of light scattering by muscle tissues at different wavelengths was represented by graphs for the collimated reflection area. The investigated method allows qualitative estimation of influence of internal or surface layers of biologic tissues optical properties on the light scattering under variable angles of incident radiation by the shape of zone of incident light.

Biomedical photometersʼ information-measuring systems with ellipsoidal reflectors have acceptable results in determining of biological tissues optical properties in the visible and near-infrared spectral range. These photometers make it possible to study the optical radiation propagation in turbid media for direct and inverse problems of light-scattering optics. The purpose of this work is to study the influence of the ellipsoidal reflectors design parameters on the results of biomedical photometry when simulating the optical radiation propagation in a system of biological tissue and reflectors in transmitted and reflected light.The paper substantiates the choice of the ellipsoidal reflectors’ focal parameter for efficient registration of forward and backscattered light. The methodology of the process is illustrated by the results of a model experiment using the Monte Carlo simulation for samples of human brain white and gray matter at the visible range of 405 nm, 532 nm, and 650 nm. The total transmittance, diffuse reflectance, and absorption graphs depending on the sample thickness were obtained. Based on the introduced concepts of the ellipsoidal reflector efficiency index and its efficiency factor, the expediency of choosing the ellipsoidal reflectors focal parameter is analyzed to ensure the registration of the maximum amount of scattered light. The graphs of efficiency index in reflected and transmitted light for different thickness samples of white and gray matter and efficiency factors depending on the sample thickness were obtained.The influence of the reflectors ellipticity on the illuminance of various zones of photometric images using the example of an absorbing biological medium – pig liver tissue – at wavelength of 405 nm with a Monte Carlo simulation was analyzed.The optical properties of biological media (scattering and absorption coefficients, scattering anisotropy factor, refractive index) and the samples’ geometric dimensions, particularly the thickness, are predetermined when choosing the ellipsoidal reflectors parameters for registration of the scattered light. Coordinates of the output of photons and their statistical weight obtained in the Monte Carlo simulation of light propagation in biological tissue have a physical effect on a characteristic scattering spot formation in the receiving plane of a biomedical photometer with ellipsoidal reflectors.

The article introduces the off-axis ellipsoidal mirror processing and testing, and uses AutoCAD software to calculate the maximum aspheric mirrors degrees. After processing the off-axis ellipsoidal reflector inclination error of 1.55arcsec, root mean square roughness ((RMS) of 3.21nn, focal length error is less than 1mm, and the surface accuracy can reach λ / 6 (0.51-0.98 μ m).

Generally, automobiles are typically equipped with separate headlamp lanterns for generating low- and high-beam light. Compared with separate headlamp lanterns, a single headlamp producing both low- and high-beam light can be more compact and have less mechanical complexity. The single headlamp structure has become a main emphasis of research that manufacturers will continue to focus great efforts on in the future. A novel design of a single headlamp generating both low- and high-beam light is proposed in this study. The proposed headlamp consists of a compound ellipsoidal reflector, a baffle plate, a condenser lens, and LED array devices generating low- and high-beam light. The compound ellipsoidal reflector comprises a primary ellipsoidal reflector for generating low-beam light and a secondary ellipsoidal reflector for generating high-beam light. Monte Carlo ray tracing simulations were performed to confirm the optical characteristics of the proposed design. A prototype of the proposed headlamp was also fabricated and assembled to verify the design’s effectiveness. The simulated and measured illuminance distributions of the low-beam and high-beam light had the desired light patterns. Moreover, all the simulated and measured illuminances of each point and line met the ECE R112 regulation for low-beam and high-beam light. The proposed headlamp in this study is feasible for the application of single headlamp generating both low- and high-beam light.

The aim of this diploma thesis is to design a suitable reflector concentrating a light beam into a circular hole in a gobo. The light beam behind the screen should have good efficiency and at the same time good homogeneity. For the reflector design and analysis a software for designing optical systems called LightTools was used. The reflector was designed by six different methods. Several smooth and several faceted reflectors were designed. The selected reflector was analyzed in combination with a varifocal lens. For selected reflector was designed mechanical store with respect to the anticipated operating conditions. This thesis serves as the basis for the producing of the reflector.

У роботі вирішено комплекс задач, що дозволило вирішити важливу науково-прикладну проблему розробки методу побудови і застосування еліпсоїдальних рефлекторів в системах реєстрації та аналізу розсіяного оптичного випромінювання, а також апробації нових конструктивних, функціональних та медико-біологічних рішень. Це дало змогу теоретично та експериментально обґрунтувати метод і апаратні засоби застосування еліпсоїдальних рефлекторів для фотометрії світлорозсіяння біологічними середовищами при виявленні їх оптичних властивостей та ідентифікації фізичного та фізіологічного стану. Запропоновано фундаментальну основу вирішення вказаної проблеми завдяки вперше розробленого механізму рей-трейсингу, що взаємо пов’язує параметри джерела випромінювання, біологічного середовища, еліпсоїдального дзеркала та матричного приймача випромінювання в інформаційно-вимірювальній системі біомедичного фотометру з еліпсоїдальними рефлекторами, і який дозволяє вирішувати пряму та інверсну задачі поширення оптичного випромінювання методом статистичного моделювання Монте-Карло.
The thesis is devoted to the solution of the important scientifically applied problem of development the construction and application method of ellipsoidal reflectors in the registration and analysis systems of scattered optical radiation, as well as approbation of new structural, functional and biomedical solutions. This made it possible to theoretically and experimentally substantiate the method and hardware of the use the ellipsoidal reflectors for photometry of light scattering by biological media in the detection of their optical properties and identification of physical and physiological state. A fundamental basis for solving this problem is the first-time developed mechanism of ray-tracing, which colligate the parameters of the radiation source, biological media, ellipsoidal reflector and matrix photodetector in the information-measuring system of biomedical photometer, which allows to solve the direct and inverse problems of light propagation by the Monte Carlo statistical simulation. The main content of the thesis is outlined in eight chapters, which present and substantiate the goal and results of the work. The first chapter presents the results of analytical review and literary search, which reveal the tasks raised in the doctorate thesis. In particular, the methods of biophotonics that are most commonly used in the study of different biological media are given. The features of optical radiation propagation in biological media are analyzed, as well as the basic principles of the transfer radiative theory, which mathematically and analytically interpret this process. Typical photometric tools used for the study of biological media, boundary conditions of their use, and functional limitations are analyzed. The second chapter is devoted to the development a method of investigation the biological media optical properties. Structural schemes of basic photometers with ellipsoidal reflectors and features of their functioning are presented. The mathematical apparatus for calculating the ray tracing in a reflector with an internal ellipsoidal reflecting surface is presented, and the main types of ray trajectories are considered. The algorithm of the proposed mechanism of ray tracing and the features of its software are presented. The results of aberration analysis of ellipsoidal reflector are shown. The third chapter is devoted to the development of Monte Carlo models of light propagation in the information-measuring system of biomedical photometer with ellipsoidal reflectors. The features of the input data formation and the basic simulation algorithm are substantiated, as well as the boundary conditions of simulation. The analytical models of software adaptation of radiation source parameters, the receiving system, as well as the boundaries and scattering-absorption properties of the biological media that underlie the simulation are presented. The principles of determination the optical coefficients, algorithm and grounds of software implementation of Monte Carlo simulation in the system "radiation source + biological media + measuring tool" are presented. In the fourth chapter proposed the features of designing photometers with ellipsoidal reflectors by improving the standard equipment for microscopy, as well as in the construction of individual prototypes. Schemes of zone analysis at processing of photometric images obtained by photometry by ellipsoidal reflectors are considered. Mathematical and analytical aspects of solving the inverse problem of the radiative transfer theory by methods of Kubelka-Munk and inverse Monte-Carlo in the context the work of biomedical photometers with ellipsoidal reflectors operating in reflected and also in reflected and transmitted light are presented. The interrelation of photometric images and optical properties of the investigated biological media is considered. In the fifth chapter discusses the technological principles of ellipsoidal reflectors production and control. The materials choice of ellipsoid for different methods of shaping the aspherical surface is substantiated. The principles of production of metallic mirror ellipsoids of revolution using vertical-boring technology, as well as 3D printing technology from plastic are formulated. Practical aspects of applying a mirror coating to the inner ellipsoidal surface from plastic are determined. The analytical model and technical stages the shape control of the ellipsoidal surface are presented and photometric comparison of the functioning of reflectors produced by different technologies is made. The sixth chapter is devoted to the analysis of the effects of light scattering in the system "radiation source + biological media + measuring tool" for different profiles of energy distribution in the laser beam and their effect on the relative illuminance distribution of photometric image at zone analysis for different layers of human skin. The influence the parameters of ellipsoidal reflectors on the boundary geometric properties of optical radiation in the forward and backscattered light is considered. The influence the diameter and power of the incident beam at the tasks of Raman spectroscopy by ellipsoidal reflectors is also substantiated. In the seventh chapter features of application the photometry by ellipsoidal reflectors for creation and improvement tools of biological and medical diagnostics and control are shown. The influence of the scattering anisotropy factor on the illuminance of photometric images and the possibility of biomedical goniophotometry were evaluated. A measurement system for angular photometry in backscattered light was developed and investigated. Based on the model experiment, the prospects of using a photometer with ellipsoidal reflectors to control the optical clearing of human skin were evaluated. A prototype optical non-invasive glucometer with ellipsoidal reflectors was created and its functional features were investigated. The eighth chapter discusses the prospects of applying the mirror ellipsoids of revolution method for various problems in optical biomedical diagnostics.
В работе решен комплекс задач, позволивший решить важную научно-прикладную проблему разработки метода построения и применения эллипсоидальных рефлекторов в системах регистрации и анализа рассеянного оптического излучения, а также апробации новых конструктивных, функциональных и медико-биологических решений. Это позволило теоретически и экспериментально обосновать метод и аппаратные средства применения эллипсоидальные рефлекторов для фотометрии светорассеяния биологическими средами при обнаружении их оптических свойств и идентификации физического и физиологического состояния. Предложено фундаментальную основу решения указанной проблемы за счет впервые разработанного механизма рей-трейсинга, что взаимно связывает параметры источника излучения, биологической среды, эллипсоидального зеркала и матричного приемника излучения в информационно-измерительной системе биомедицинского фотометра с эллипсоидальными рефлекторами, и который позволяет решать прямую и инверсную задачи распространения оптического излучения методом статистического моделирования Монте-Карло.

碩士
國立中山大學
物理學系研究所
99
In this study, a double-ellipsoid structure is proposed for measurements of optical properties of liquid-crystal displays (LCDs). By using the double-ellipsoid structure, light dispersion and measurement time, which occurs during the measurement of optical properties of LCDs, can be greatly reduced. The system also significantly decreases reflective loss on interface, increasing the accuracy of the measurement. Moreover, by using the conoscopy measured from the proposed structure, light distribution of the dark state along off-axis direction can be analyzed. Based on the analysis, the cell gap and pretilt angle of vertical alignment liquid-crystals (VA-LCs) are evaluated. The proposed structure, which exhibits a fast and high accuracy measurement, is highly promising for future optical measurement of LCDs.

The optical characteristics of a high-flux solar simulator that comprises an array of Xe-arc lamps with ellipsoidal specular reflectors of common focus is examined using the Monte Carlo ray tracing technique. The parameters varied are arc diameter, focal length, eccentricity, truncation diameter, and angular error of specular reflection. The geometrical design of the truncated ellipsoidal reflector is optimized for maximum transfer efficiency, defined as the portion of radiation intercepted by a circular target centered at the common focal point. An array of ten 15 kW Xe-arc lamps of 9 mm electrode gap and 35% electrical-to-radiant efficiency, each closed-coupled with an ellipsoidal reflector of optimum design, should be capable of delivering an average radiative power flux exceeding 5900 kW/m2 over a 6 cm-diameter circular target, with an overall transfer efficiency of 31.9%.