Mask Projection Microstereolithography (MPSLA) is an additive manufacturing process capable for fabricating true three-dimensional microparts and hence, holds promise as a potential micro-fabrication process for micro-machine components. With only a few MPSLA systems developed and studied so far, the research in this field is inchoate and experimental in nature. The process of curing a micropart using an MPSLA system has not been analytically modeled and no literature on process planning for MPSLA is available. In order to employ the MPSLA technology for microfabrication, it is necessary to model its part building process and formulate a process planning method to cure dimensionally accurate microparts. As a part of this thesis, an MPSLA system is designed and assembled. The process of curing a single layer using this system is analytically modeled as the Layer cure model. The Layer cure model is formulated in two steps. First, the irradiance received by the resin surface is modeled as a function of the system parameters (Irradiance model). Then, the resin used in the system is characterized to experimentally determine its working curve. The Irradiance model and the resin characterization enable us to compute the dimensions of any layer cured using our MPSLA system in terms of the process parameters. The Layer cure model has been validated by curing test layers on our system. Finally, the Layer cure model has been inverted to formulate a process planning method to cure layers of the required dimensions. Using this process planning method, it is possible to cure layers within a dimensional error of 3%.

Orientador: Edmea Rita Temporini Nastari / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T08:57:15Z (GMT). No. of bitstreams: 1 Bisneto_OtavioSiqueira_M.pdf: 1532415 bytes, checksum: 54c06aa08a8469404379be1a2f2c1a08 (MD5) Previous issue date: 2006 / Resumo: Objetivo: avaliar a relação entre aberrações de alta ordem, erros de refração e idade. Material e Método: realizou-se estudo retrospectivo analítico, de pacientes submetidos a exames de aberrometria. Foram incluídos neste estudo todos os sujeitos examinados no aberrômetro LADARWAVE® (Alcon, Fort Worth, Texas), no Hospital de Olhos do Paraná (Curitiba-Brasil) no período de abril de 2004 a abril de 2005, sendo o principal critério de inclusão acuidade visual corrigida ou não de 20/20 ou melhor e o principal critério de exclusão presença de cirurgia e/ou doença ocular prévia. Foram estudadas as seguintes variáveis: idade, grau de refração esféro-cilíndrica, medida do equivalente esférico, aberrações de alta ordem divididas em: coma, aberração esférica, outras e root mean square (rms) de alta ordem. Todas as variáveis foram obtidas através do exame de aberrometria realizado no aberrômetro LADARWAVE®, sob cicloplegia, considerando-se pupila de 6,5 mm. Foram avaliadas aberrações ópticas de alta ordem até a oitava ordem nos polinômios de Zernike. Os pacientes foram divididos em 6 grupos de acordo com o erro de refração e em 3 grupos de acordo com a idade. Resultados: foram avaliados 312 olhos dos quais 201 foram incluídos no estudo. A idade média desses pacientes foi de 33,9±10,1 anos variando de 7 a 62 anos. Após análise estatística, na comparação entre os grupos de acordo com o erro de refração, foi observado que os pacientes hipermétropes com astigmatismo inferior a -0,75 D (GRUPO 5) apresentaram maior quantidade de aberração esférica, e que os pacientes hipermétropes com astigmatismo superior a -0,75 D (GRUPO 6) apresentaram maior quantidade de aberrações denominadas "outras" e RMS de alta ordem. Na comparação geral entre os grupos de idade, em relação as variáveis estudadas, o grupo de pacientes com 45 ou mais anos (GRUPO C) apresentou maior quantidade de todas as aberrações estudadas. Conclusão: a) houve relação positiva, estatisticamente significativa, entre hipermetropia, com e sem astigmatismo, e aberração esférica e rms de alta ordem. b) houve relação positiva, estatisticamente significativa, entre idade e aberrações ópticas de alta ordem / Abstract: Purpose: to evaluate the relationship between high order aberrations and refraction errors, and between high order aberrations and age. Methods: an analytic retrospective study of patients that underwent aberrometry exam was done. All the subjects examined at LADARWAVE® aberrometer at Hospital de Olhos do Paraná from April 2004 to April 2005 were included in this study. The major inclusion criterion was 20/20 or better - corrected or not - visual acuity; and the major exclusion criterion, the presence of previous eye surgery or eye disease. The following variable were analyzed: age, refraction, spherical equivalent, and high order aberrations wich were: coma, spherical aberration, others, and high order root mean square (rms). All data were obtained from LADARWAVE® aberrometry exam, under ciclopegia, taking only 6.5 mm pupil results. High order aberrations up to eight order Zernike's coefficients were evaluated. Patients were divided in 6 groups according to refraction error and in 3 groups according to age. Results: out of 312 eyes, 201 were studied. The mean age of was 33.9 +- 10.1, varying from 7 to 62 years of age. After statistical analysis, it was observed that among the refraction error groups hyperopic patients with less than -0,75 D astigmatism (group 5) showed a higher amount of spherical aberration, and that hyperopic patients with more than -0,75 D astigmatism (group 6) showed a higher amount of other and high order rms aberrations. In the general comparison between the age groups, the 45 or older group (group C) showed a higher amount of all the aberrations analyzed. Conclusion: a) there was a statiscally significant positive relation between hyperopia - with or without astigmatism - and spherical aberration and high order rms. b) there was a statiscally significant positive relation between age and all aberrations analyzed. / Mestrado / Oftalmologia / Mestre em Ciências Médicas

L’objectif de la thèse est de développer une nouvelle technique d’optique adaptive pour les interferomètres gravitationels avancés, basée sur un nouveau type de miroir pour le faisceau d’injection de l’interferomètre. Le miroir déformable, basé sur une actuation thermique, doit etre un outil compatible ultra-vide, qui fonctionne sans bruit électronique ou mécanique, bon marché et permettre la correction des modes d’ordre supérieurs afin d’améliorer le matching des faisceaux de haute puissance dans les cavités laser du détecteur sous ultra-vide. Un montage experimental de caractérisation du miroir déformable a été mis en place afin d’effectuer les tests de validation du premier prototype sous air. L’élaboration d’une procédure de caractérisation des propriétés du miroir et d’une boucle de controle a permis de développer une approche efficace pour déterminer les possibilités et les limites du miroir. Nous avons ainsi pu faire la démonstration de sa capacite a corriger les aberrations de phase d’un faisceau laser infrarouge a différentes fréquences spatiales. Nous avons également démontré que le miroir vérifie les performances de stabilité, de reproductibilité et de linearité attendues. Nous avons ensuite validé l’amélioration du mode matching d’un faisceau laser sur une cavité de réference par le miroir thermiquement déformable / In this thesis we develop a new technique of adaptive optics for the Advanced Gravitational Interferometers, based on a new type of deformable mirror for the injection beam of the interferometer. This deformable mirror, based on a thermal actuation, has to be a high vacuum compatible and low-cost device, that is working without any electronic or mechanic noise. It has to allow the correction of high order modes to improve the matching of high power laser beams in the interferometer.An experimental setup has been made to characterize the first prototype on air. An efficient process and a control loop have allowed to determine the possibilities and limits of the device. We have demonstrated its ability to correct high order modes of an infrared laser beam. Afterwards, we have validated the improvement of mode matching into a fixed cavity.

Les défaut de la vision sont analysés et classés à partir des caractéristiques mathématiques du front d’onde de l’oeil considéré. Après avoir présenté la méthode actuelle basée sur la décomposition du front d’onde dans la base orthonormale de Zernike ainsi que certaines de ses limitations, on propose ici une nouvelle base de décomposition. Celle-ci repose sur l’utilisation del’espace des fronts d’onde polynomiaux de valuation supérieure ou égale à L + 1 (où L est un entier naturel) et permet de décomposer de manière unique un front d’onde polynomial en la somme d’un front d’onde polynomial de bas degré (inférieur ou égal à L) et un front d’onde polynomial de haute valuation (supérieure ou égal à L + 1). En choisissant L = 2, une nouvelle décomposition est obtenue, appelée D2V3, où le front d’onde polynomial de haut degré ne comporte pas de termes de degré radial inférieur ou égal à deux. Cette approche permet de dissocier parfaitement les aberrations optiques corrigibles ou non par le port de lunettes. Différents cas cliniques présentés dans la dernière section permettent de mettre en évidence l’intérêt de cette nouvelle base de décomposition. / The eye vision defaults are analyzed and classified by studyingthe corresponding eye wavefront. After presenting the orthogonal basis, called the Zernike basis, that is currently used for the medical diagnosis, a new decomposition basis is built. It is based on the use of the space of polynomials of valuation greater or equal to L+1 (for L a natural integer). It allows to uniquely decompose a polynomial wavefront into the sum of a polynomial of low degree (lesser or equal to L) and a polynomial of high valuation (greater or equal to L +1). By choosing L = 2, a new decomposition, called D2V3, is obtained where the polynomial wavefront of high degree does not include terms of radial degree lesser or equal to 2. In particular, it allows to quantify perfectly the aberrations that can be corrected by eyeglasses or not. Various clinical examples clearly show the interest of this new basis compared to a diagnosis based on the Zernike decomposition.

Le besoin tant en haute qualité d'imagerie qu'en structures légères est l'un des principaux moteurs pour la conception des télescopes spatiaux. Un contrôle efficace du front d'onde va donc devenir indispensable dans les futurs grands observatoires spatiaux, assurant une bonne performance optique tout en relâchant les contraintes sur la stabilité globale du système. L'optique active consiste à contrôler la déformation des miroirs, cette technique peut être utilisée afin de compenser la déformation des grands miroirs primaires, afin de permettre l'utilisation d'instrument reconfigurable ou afin de fabriquer des miroirs asphériques avec le polissage sous contraintes. Dans ce manuscrit, la conception de miroirs actifs dédiés à l'instrumentation spatiale est présentée. Premièrement, un système compensant la déformation d'un grand miroir allégé dans l'espace est conçu et ses performances sont démontrées expérimentalement. Avec 24 actionneurs, le miroir MADRAS (Miroir Actif Déformable et Régulé pour Applications Spatiales) effectuera une correction efficace du front d'onde dans un relais de pupille du télescope. Deuxièmement, un harnais de déformation pour le polissage sous contraintes des segments du télescope géant européen de 39 m (E-ELT) est présenté. La performance du procédé est prédite et optimisée avec des analyses éléments finis et la production en masse des segments est considérée. Troisièmement, deux concepts originaux de miroirs déformables avec un nombre minimal d'actionneurs ont été développés. VOALA (Variable Off-Axis parabola) est un système à trois actionneurs et COMSA (Correcting Optimized Mirror with a Single Actuator) est un système à un actionneur. / The need for both high quality images and light structures is one of the main driver in the conception of space telescopes. An efficient wave-front control will then become mandatory in the future large observatories, ensuring the optical performance while relaxing the specifications on the global system stability. Consisting in controlling the mirror deformation, active optics techniques can be used to compensate for primary mirror deformation, to allow the use of reconfigurable instruments or to manufacture aspherical mirror with stress polishing. In this manuscript, the conception of active mirrors dedicated to space instrumentation is presented. Firstly, a system compensating for large lightweight mirror deformation in space, is designed and its performance are experimentally demonstrated. With 24 actuators, the MADRAS mirror (Mirror Actively Deformed and Regulated for Applications in Space) will perform an efficient wave-front correction in the telescope's pupil relay. Secondly, a warping harness for the stress polishing of the 39 m European Extremely Large Telescope segments is presented. The performance of the process is predicted and optimized with Finite Element Analysis and the segments mass production is considered. Thirdly, two original concepts of deformable mirrors with a minimum number of actuators have been developed. The Variable Off-Axis parabola (VOALA) is a 3-actuators system and the Correcting Optimized Mirror with a Single Actuator (COMSA) is a 1-actuator system.

La filière solaire thermodynamique concentrée est une des voies les plus prometteuses pour la production des énergies renouvelables du futur. L’efficacité des surfaces optiques est un des facteurs clés influant sur les performances d’une centrale. Un des défis technologiques restant à résoudre concerne le temps et les efforts nécessaires à l’ajustement et l’orientation de tous ces miroirs, ainsi que la calibration des héliostats pour assurer un suivi précis de la course du soleil et une concentration contrôlée. Le travail présenté dans ce manuscrit propose une réponse à ce problème par le développement d’une méthode de caractérisation des héliostats dite de « rétrovisée », consistant à placer quatre caméras au voisinage du récepteur pour enregistrer les répartitions de luminance occasionnées par la réflexion du soleil sur l’héliostat. La connaissance du profil de luminance solaire, combiné à ces quatre images, permet de reconstruire les pentes des erreurs optiques de l’héliostat.La première étape de l’étude de la méthode a consisté à établir les différentes équations permettant de reconstruire les pentes des surfaces optiques à partir des différents paramètres du système. Ces différents développements théoriques ont ensuite permis la réalisation de simulations numériques pour valider la méthode et définir ses possibilités et ses limites. Enfin, des tests expérimentaux ont été réalisés sur le site de la centrale Thémis. À la suite de ces expériences, des pistes d’améliorations ont été identifiées pour améliorer la précision expérimentale et envisager son déploiement industriel. / Concentrated solar power is a promising way for renewable energy production. Optical efficiency of the mirrors is one of the key factors influencing a power plant performance. Methods which allow the operator to adjust all the heliostat of a plant quickly, in addition of calibration and tracking, are essential for the rise of the technology. The work presented in this thesis is the study of a “backward-gazing” method consisting in placing four cameras near the receiver simultaneously recording brightness images of the sun reflected by the heliostat. The optical errors of the mirrors are retrieved from these four images and the knowledge of the one dimension sun radiance profile.The first step of the study consists in the theoretical description of the method. Then numerical simulations are performed to estimate the general accuracy and the limits of the backward-gazing method. In a third phase, experimental tests have been fulfilled at Themis solar power plant. Finally, ideas of improvement are proposed based on the experiments performed.

The wavefront reconstruction of a light wave transformed by a microscope objective is the main subject of this diploma thesis together with the design and assembly of a~measuring device and the development of a computational algorithm. The purpose is to determine optical aberrations and to compare a quality of objectives with identical parameters. The term wavefront is explained and its description using Zernike polynomials is introduced in the first part of the thesis. The following part summarizes possible methods for wavefront reconstrucion. Two methods were chosen for experimental determination of a wavefront shape – shearing interferometry and solution of the transport of intensity equation. For each method a brief characteristic is provided together with possible applications, mathematical apparatus, image processing, computational procedure, setup description and proposition and results of experiments. The suitability of both methods for optical aberration determination and microscope objective comparison is discussed. Based on the obtained results, both methods were found to be suitable for comparison of microscope objectives. The suitability for optical aberration determination is possible with certain restrictions.

In space exploration optical imaging is one of the key measurements conducted, with a vast majority of missions heavily relying on optical data acquisition to examine alien worlds. One such endeavor is ESA’s F-class mission Comet Interceptor, a multi-element spacecraft expected to be launched in 2028. It consists of a primary platform and two sub-spacecraft, one of which carrying the Optical Periscopic Imager for Comets (OPIC). An accurate prediction of the generated imagery is of undeniable importance as mission planning and instrument design strongly depend on the real-world output quality of the camera system. In the case of OPIC, the collected image data will be used to reconstruct three dimensional models of targeted celestial bodies. Furthermore, the sub-spacecraft faces a risk of high velocity dust impacts, leading to a limited number of data samples to be broadcasted back to the primary spacecraft before collision. Testing image prioritization algorithms and reconstruction methods prior to mission start requires accurate computer-generated images. Camera sensors and lens systems are subjected to various optical distortions and aberrations that degrade the final image. Popular render engines model those effects to a certain degree only and as a result produce content that is looking too perfect. While more sophisticated software products exist, they often come with compatibility limitations and other drawbacks. This report discusses the most important optical aberrations, as well as their relevance for optical instruments in space applications with a particular focus on the Comet Interceptor mission. The main part of this work is however the implementation of a dedicated software tool that simulates a variety of optical aberrations complementing the basic camera model of the Blender render engine. While its functionality is mostly demonstrated for OPIC, the software is designed with a broad range of usage scenarios in mind.

No description available.

Disertacijos darbo tikslas buvo, modeliuojant bei vykdant eksperimentus, išanalizuoti siūlomo sudėtinio aktyvaus lazerio elemento koncepcijos prielaidas ir taikymų galimybes, bei surasti veiksnius, ribojančius pasiūlyto sudėtinio aktyvaus lazerio elemento galimybes. Šiame darbe buvo pasiūlytas lazerio aktyvusis elementas, kuris apjungia įvairių tipų lazerinių aktyviųjų elementų gerąsias savybes. Tačiau eksperimentai parodė, jog toks sudėtinis elementas neturi pranašumo prieš plačiai naudojamus strypo formos lazerinius aktyviuosius elementus. Siekiant paaiškinti susidarančių optinių iškraipymų priežastis, buvo sukurti ir pritaikyti teoriniai modeliai, aprašantys aktyvios terpės optines, termo-optines bei termo-mechanines savybes. Sukurtas optinių iškraipymų vertinimo metodas, leidžiantis palyginti skirtingų konfigūracijų elementus šiluminių reiškinių sąlygotų optinių iškraipymų atžvilgiu. Taip pat pateiktas paprastas modelis, gerai aprašantis iš daugiamodžio šviesolaidžio išėjusios kaupinimo spinduliuotės intensyvumo skirstinio kitimą. Visi pateikti teoriniai modeliai buvo patvirtinti eksperimentiniais matavimais. Naudojantis sukurtais teoriniais modeliais buvo nustatyta, jog pagrindinė optinių iškraipymų priežastis siūlomame sudėtiniame lazeriniame elemente yra nelegiruota terpė tarp plonų legiruotų sluoksnių, kurioje vykstantys šiluminiai reiškiniai riboja tokio lazerinio aktyvaus elemento galimybes. / The aim of this PhD thesis was to investigate the concept and application abilities of a proposed composite laser element finding factors that limit performance of such laser element. In this work a composite laser element was proposed which combines decent properties of various laser elements. Nevertheless, experiments showed that such element has no advantage over a widely used rod type active laser elements. In order to explain the nature of induced optical aberrations, theoretical models describing optical, thermo-optical and thermo-mechanical properties of active medium were developed and applied. An original method to rate induced optical aberrations which allow unambiguous comparison of different aberrations was presented. A simple model to calculate the variation of intensity distribution as the beam propagates was presented also. All models were confirmed experimentally. Using developed models it was found that the main cause of optical aberrations in the proposed element is the undoped medium between thin doped layers. Generally, abilities of proposed active laser elements are limited by thermal effects in the undoped medium.