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Concentration of solar energy may be obtained by reflection, refraction, or a combination of the two. The collectors of a reflection system are designed to concentrate the sun’s rays onto a photovoltaic cell or steam tube. Refractive lenses concentrate light by having it travel through the lens. The sun’s rays are partially reflected and then refracted via a hybrid technique. Hybrid focus techniques have the potential to maximize power output. Fresnel lenses are an efficient tool for concentrating solar energy, which may then be used in a variety of applications. Development of both imaging and non-imaging devices is occurring at this time. Larger acceptance angles, better concentration ratios with less volume and shorter focal length, greater optical efficiency, etc., are only some of the advantages of non-imaging systems over imaging ones. This study encompasses numerical, experimental, and numerical and experimental studies on the use of Fresnel lenses in various solar energy systems to present a comprehensive picture of current scientific achievements in this field. The framework, design criteria, progress, and difficulties are all dissected in detail. Accordingly, some recommendations for further studies are suggested.

Concentration of solar energy may be obtained by reflection, refraction, or a combination of the two. The collectors of a reflection system are designed to concentrate the sun’s rays onto a photovoltaic cell or steam tube. Refractive lenses concentrate light by having it travel through the lens. The sun’s rays are partially reflected and then refracted via a hybrid technique. Hybrid focus techniques have the potential to maximize power output. Fresnel lenses are an efficient tool for concentrating solar energy, which may then be used in a variety of applications. Development of both imaging and non-imaging devices is occurring at this time. Larger acceptance angles, better concentration ratios with less volume and shorter focal length, greater optical efficiency, etc., are only some of the advantages of non-imaging systems over imaging ones. This study encompasses numerical, experimental, and numerical and experimental studies on the use of Fresnel lenses in various solar energy systems to present a comprehensive picture of current scientific achievements in this field. The framework, design criteria, progress, and difficulties are all dissected in detail. Accordingly, some recommendations for further studies are suggested.

Concentration of solar energy may be obtained by reflection, refraction, or a combination of the two. The collectors of a reflection system are designed to concentrate the sun’s rays onto a photovoltaic cell or steam tube. Refractive lenses concentrate light by having it travel through the lens. The sun’s rays are partially reflected and then refracted via a hybrid technique. Hybrid focus techniques have the potential to maximize power output. Fresnel lenses are an efficient tool for concentrating solar energy, which may then be used in a variety of applications. Development of both imaging and non-imaging devices is occurring at this time. Larger acceptance angles, better concentration ratios with less volume and shorter focal length, greater optical efficiency, etc., are only some of the advantages of non-imaging systems over imaging ones. This study encompasses numerical, experimental, and numerical and experimental studies on the use of Fresnel lenses in various solar energy systems to present a comprehensive picture of current scientific achievements in this field. The framework, design criteria, progress, and difficulties are all dissected in detail. Accordingly, some recommendations for further studies are suggested.

Concentration of solar energy may be obtained by reflection, refraction, or a combination of the two. The collectors of a reflection system are designed to concentrate the sun’s rays onto a photovoltaic cell or steam tube. Refractive lenses concentrate light by having it travel through the lens. The sun’s rays are partially reflected and then refracted via a hybrid technique. Hybrid focus techniques have the potential to maximize power output. Fresnel lenses are an efficient tool for concentrating solar energy, which may then be used in a variety of applications. Development of both imaging and non-imaging devices is occurring at this time. Larger acceptance angles, better concentration ratios with less volume and shorter focal length, greater optical efficiency, etc., are only some of the advantages of non-imaging systems over imaging ones. This study encompasses numerical, experimental, and numerical and experimental studies on the use of Fresnel lenses in various solar energy systems to present a comprehensive picture of current scientific achievements in this field. The framework, design criteria, progress, and difficulties are all dissected in detail. Accordingly, some recommendations for further studies are suggested.

Concentration of solar energy may be obtained by reflection, refraction, or a combination of the two. The collectors of a reflection system are designed to concentrate the sun’s rays onto a photovoltaic cell or steam tube. Refractive lenses concentrate light by having it travel through the lens. The sun’s rays are partially reflected and then refracted via a hybrid technique. Hybrid focus techniques have the potential to maximize power output. Fresnel lenses are an efficient tool for concentrating solar energy, which may then be used in a variety of applications. Development of both imaging and non-imaging devices is occurring at this time. Larger acceptance angles, better concentration ratios with less volume and shorter focal length, greater optical efficiency, etc., are only some of the advantages of non-imaging systems over imaging ones. This study encompasses numerical, experimental, and numerical and experimental studies on the use of Fresnel lenses in various solar energy systems to present a comprehensive picture of current scientific achievements in this field. The framework, design criteria, progress, and difficulties are all dissected in detail. Accordingly, some recommendations for further studies are suggested.

ISBN: 978-081948795-7 CODEN: PSISD Copyright 2011 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited., Fresnel lenses and other faceted or micro-optic devices are increasingly used in multiple applications like solar light concentrators and illumination devices, just to name some representative. However, it seems to be a certain lack of adequate techniques for the assessment of the performance of final fabricated devices. As applications are more exigent this characterization is a must. We provide a technique to characterize the performance of Fresnel lenses, as light collection devices. The basis for the method is a configuration where a camera images the Fresnel lens aperture. The entrance pupil of the camera is situated at the focal spot or the conjugate of a simulated solar source. In this manner, detailed maps of the performance of different Fresnel lenses are obtained for different acceptance angles., Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub

It is well established that renewable energy resources for electricity generation are free. In hot areas, solar energy has become one of the major interests of researchers and specialists. This paper aims to experimentally investigate the maximum voltage generation of a thermoelectric generator (TEG) panel. This panel was built from many TEG modules that are connected in series and in parallel. The panel was exposed to high heat due to solar radiation during summer, either directly or through a Fresnel lens. The other side of the TEG panel was cooled using tap water that was passed through aluminum heat exchangers in an active cooling method. It was found that the maximum open-circuit voltage of this TEG panel using a Fresnel lens was 9.35 V. With no lens, it was 11.75 V at 14:00 h local time. The experiments were done during a sunny July period in Iraq. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Fresnel lenses are used in a wide range of solar energy applications, primarily due to their reduced material usage, low cost, and high optical efficiency. This study presents an investigation of the world’s first full-scale Fresnel lens solar collector field. The collector field consists of 144 two-axis tracking solar collectors manufactured by the Danish company Heliac and supplies heat to the local district heating network in Lendemarke, Denmark. The thermal performance of the solar collector field was determined using the quasi-dynamic test method. It was found that the peak efficiency was 11% lower compared to a brand-new collector and that heat losses from the collectors made up half of the total heat losses of the solar field. The reduction in the peak efficiency was primarily caused by soiling as the collectors were exposed to outdoor conditions for one year without cleaning. Furthermore, the system’s annual performance was determined using a simulation model developed in TRNSYS and validated by comparison to measurement data. For 2020, the heat generation was 373 kWh/m2 (relative to aperture area) when operating with an outlet temperature of 90 °C and inlet temperature of 50 °C. Additionally, a sensitivity analysis of the annual heat generation was performed, varying the ground cover ratio, mean collector temperature, and soiling level. The sensitivity analysis showed that the heat generation was relatively insensitive to changes in the mean collector temperature, demonstrating that the collectors are suitable for generating heat above 100 °C, unlike flat-plate collectors.

Photoalignment on azo dye films is a simple and efficient way to achieve anisotropic ordering of molecules, which is promising to achieve ultra-thin high-performance dichroic polarizers. Besides, the photoalignment technique shows a unique advantage on patterned alignment applications, and enables the realization of advanced optical elements such as liquid crystal (LC) Dammann grating, LC Fresnel lens, holographic polarizers and bifocal optical-vortex lens. © 2022 SPIE.

Concentrating Photo Voltaic (CPV) systems maximize energy harvested from the sun with multi-junction solar cells of less area, reducing related implementation costs and reaching energy production thresholds up to 38,9 %. Nowadays, CPV systems are generally implemented in solar energy farms in a permanent location, however, these systems could be used in other dynamic contexts, such as vehicles or portable devices. In this way, mechanical and geometrical parameters related to manipulation, transportation and installation should be carefully considered at the design stage. Besides, each condition of use presents different variables affecting these parameters. In all, there is not an established architecture for these systems, opening up the possibility of radically changing their use, geometry and components. Therefore, a concept of a methodical process for designing of CPV systems is proposed in order to predict their behavior in terms of implementation and energy production. This might allow the development of robust concepts that can be adapted to different context of use as required, providing an itinerant character and thus extending the field of implementation of these systems beyond a static use. The relevant variables for the use of CPV systems are determined through experimentation considering the implementation of Fresnel lenses as light concentrators. This allows generating a structured design guide composed of different methods of measurement, selection and development. The methodical process is based on a perspective of functional modules considering needs, technical aspects and particular usage conditions of each design and it would provide appropriate guidelines in each circumstance.

Solar competition cars are a very interesting research laboratory for the development of new technologies heading to their further implementation in either commercial passenger vehicles or related applications. Besides, worldwide competitions allow the spreading of such ideas where the best and experienced teams bet on innovation and leading edge technologies, in order to develop more efficient vehicles. In these vehicles, some aspects generally make the difference such as aerodynamics, shape, weight, wheels and the main solar panels. Therefore, seeking to innovate in a competitive advantage, the first Colombian solar vehicle "Primavera", competitor at the World Solar Challenge (WSC)-2013, has implemented the usage of a Concentrating Photovoltaic (CPV) system as a complementary solar energy module to the common silicon photovoltaic panel. By harvesting sunlight with concentrating optical devices, CPVs are capable of maximizing the allowable photovoltaic area. However, the entire CPV system weight must be less harmful than the benefit of the extra electric energy generated, which in adjunct with added manufacture and design complexity, has intervened in the fact that CPVs had never been implemented in a solar car in such a scale as the one described in this work. Design considerations, the system development process and implementation are presented in this document considering both the restrictions of the context and the interaction of the CPV system with the solar car setup. The measured data evidences the advantage of using this complementary system during the competition and the potential this technology has for further developments. © 2014 SPIE.

[ES] El objetivo de este proyecto es producir y validar un modelo tridimensional para el proceso de moldeo por inyección polimérica de componentes ópticos micro estructurados. Para llevar a cabo las simulaciones, se utilizará el software comercial Moldflow®. Las piezas a modelar son lentes de Fresnel, un tipo de lente compacta utilizada en multitud de campos en los que se requiera concentrar luz, desde en fotografía e imagen hasta en la industria del automóvil. Aunque las lentes de Fresnel son macroscópicas, suelen contener elementos microscópicos que deben ser también modelados. Esto hace difícil la obtención de un modelo que resulte preciso, ya que se deben aplicar procedimientos de modelado especiales para mimetizar de forma precisa el comportamiento tanto de las partes microscópicas como de las macroscópicas. En este proyecto, se estudiarán los requisitos y limitaciones del modelado a escala microscópica y se aplicarán nuevas técnicas de refinamiento de la malla para obtener un modelo tridimensional fiable del proceso. El proceso de moldeo por inyección será simulado y estudiado bajo distintas condiciones de inyección. Las simulaciones se validarán mediante experimentos de inyección., [EN] The aim of this project is to build and validate a three-dimensional model of micro-structured optical components produced using injection moulded polymers. To simulate the injection moulding process, the commercial software Moldflow® will be used. Parts to be modelled are Fresnel lenses, a kind of compact lens used for many fields involving light concentration, from automotive industrie to imaging and photography. Even Fresnel lenses are macorscopic, they often have microscopic elements that have also to be modeled. This makes an adequate model difficult to obtain as special techniques have to be used in orde to accurately mimic the piece. On this project, the requirements and limitations of the micro structured components modeling will be studied, applying new mesh refinement techniques to obtain a valid three dimensional model of the process.The injection moulding process will be simulated and studied under different injection conditions. Simulations will be validated using injection moulding experiments.

[ES] El objetivo de este proyecto es producir y validar un modelo tridimensional para el proceso de moldeo por inyección polimérica de componentes ópticos micro estructurados. Para llevar a cabo las simulaciones, se utilizará el software comercial Moldflow®. Las piezas a modelar son lentes de Fresnel, un tipo de lente compacta utilizada en multitud de campos en los que se requiera concentrar luz, desde en fotografía e imagen hasta en la industria del automóvil. Aunque las lentes de Fresnel son macroscópicas, suelen contener elementos microscópicos que deben ser también modelados. Esto hace difícil la obtención de un modelo que resulte preciso, ya que se deben aplicar procedimientos de modelado especiales para mimetizar de forma precisa el comportamiento tanto de las partes microscópicas como de las macroscópicas. En este proyecto, se estudiarán los requisitos y limitaciones del modelado a escala microscópica y se aplicarán nuevas técnicas de refinamiento de la malla para obtener un modelo tridimensional fiable del proceso. El proceso de moldeo por inyección será simulado y estudiado bajo distintas condiciones de inyección. Las simulaciones se validarán mediante experimentos de inyección., [EN] The aim of this project is to build and validate a three-dimensional model of micro-structured optical components produced using injection moulded polymers. To simulate the injection moulding process, the commercial software Moldflow® will be used. Parts to be modelled are Fresnel lenses, a kind of compact lens used for many fields involving light concentration, from automotive industrie to imaging and photography. Even Fresnel lenses are macorscopic, they often have microscopic elements that have also to be modeled. This makes an adequate model difficult to obtain as special techniques have to be used in orde to accurately mimic the piece. On this project, the requirements and limitations of the micro structured components modeling will be studied, applying new mesh refinement techniques to obtain a valid three dimensional model of the process.The injection moulding process will be simulated and studied under different injection conditions. Simulations will be validated using injection moulding experiments.

[ES] El objetivo de este proyecto es producir y validar un modelo tridimensional para el proceso de moldeo por inyección polimérica de componentes ópticos micro estructurados. Para llevar a cabo las simulaciones, se utilizará el software comercial Moldflow®. Las piezas a modelar son lentes de Fresnel, un tipo de lente compacta utilizada en multitud de campos en los que se requiera concentrar luz, desde en fotografía e imagen hasta en la industria del automóvil. Aunque las lentes de Fresnel son macroscópicas, suelen contener elementos microscópicos que deben ser también modelados. Esto hace difícil la obtención de un modelo que resulte preciso, ya que se deben aplicar procedimientos de modelado especiales para mimetizar de forma precisa el comportamiento tanto de las partes microscópicas como de las macroscópicas. En este proyecto, se estudiarán los requisitos y limitaciones del modelado a escala microscópica y se aplicarán nuevas técnicas de refinamiento de la malla para obtener un modelo tridimensional fiable del proceso. El proceso de moldeo por inyección será simulado y estudiado bajo distintas condiciones de inyección. Las simulaciones se validarán mediante experimentos de inyección., [EN] The aim of this project is to build and validate a three-dimensional model of micro-structured optical components produced using injection moulded polymers. To simulate the injection moulding process, the commercial software Moldflow® will be used. Parts to be modelled are Fresnel lenses, a kind of compact lens used for many fields involving light concentration, from automotive industrie to imaging and photography. Even Fresnel lenses are macorscopic, they often have microscopic elements that have also to be modeled. This makes an adequate model difficult to obtain as special techniques have to be used in orde to accurately mimic the piece. On this project, the requirements and limitations of the micro structured components modeling will be studied, applying new mesh refinement techniques to obtain a valid three dimensional model of the process.The injection moulding process will be simulated and studied under different injection conditions. Simulations will be validated using injection moulding experiments.

[ES] El objetivo de este proyecto es producir y validar un modelo tridimensional para el proceso de moldeo por inyección polimérica de componentes ópticos micro estructurados. Para llevar a cabo las simulaciones, se utilizará el software comercial Moldflow®. Las piezas a modelar son lentes de Fresnel, un tipo de lente compacta utilizada en multitud de campos en los que se requiera concentrar luz, desde en fotografía e imagen hasta en la industria del automóvil. Aunque las lentes de Fresnel son macroscópicas, suelen contener elementos microscópicos que deben ser también modelados. Esto hace difícil la obtención de un modelo que resulte preciso, ya que se deben aplicar procedimientos de modelado especiales para mimetizar de forma precisa el comportamiento tanto de las partes microscópicas como de las macroscópicas. En este proyecto, se estudiarán los requisitos y limitaciones del modelado a escala microscópica y se aplicarán nuevas técnicas de refinamiento de la malla para obtener un modelo tridimensional fiable del proceso. El proceso de moldeo por inyección será simulado y estudiado bajo distintas condiciones de inyección. Las simulaciones se validarán mediante experimentos de inyección., [EN] The aim of this project is to build and validate a three-dimensional model of micro-structured optical components produced using injection moulded polymers. To simulate the injection moulding process, the commercial software Moldflow® will be used. Parts to be modelled are Fresnel lenses, a kind of compact lens used for many fields involving light concentration, from automotive industrie to imaging and photography. Even Fresnel lenses are macorscopic, they often have microscopic elements that have also to be modeled. This makes an adequate model difficult to obtain as special techniques have to be used in orde to accurately mimic the piece. On this project, the requirements and limitations of the micro structured components modeling will be studied, applying new mesh refinement techniques to obtain a valid three dimensional model of the process.The injection moulding process will be simulated and studied under different injection conditions. Simulations will be validated using injection moulding experiments.

Fresnel lenses are optical systems used to transport light within a defined contour, regardless of the order of the message it contains, because due to its geometry, image quality is seriously affected by optical aberrations. This type of lens is usually known for its applications in lighting systems, such as sea lighthouses, study lights, etc. But they can also transport large amounts of energy for applications where high temperatures are required, as in metallurgical processes of surface treatment of materials that, in this case, is carried out at the National Center for Metallurgical Research (CENIM). To do so, it is necessary to know the characteristics and limitations of this optical system. The available data from the manufacturer may not be entirely accurate or not complete, so they have to be checked. This is why the Fresnel lens installed in the CENIM has been characterized optically and geometrically. The method has been based on determining the aperture, the radius of curvature, the focal length, the optical power, the spot size at the focus, the effective diameter of the lens at the focal point, and the flow transfer performance. This last characteristic has been tested using a block of steel and measuring the energy distribution on it.

A diagnostic stand has been created to study the parameters of laser radiation transformed by diffractive optical elements (DOE) designed for operation in the infrared range. The optical systems included in the stand allow recording the intensity distribution formed by the elements of micro-optics in different planes that is necessary to control the focusing quality and to estimate the focus depth. They also provide an opportunity to measure the DOE power efficiency. Experimental approbation of optical systems on the example of a reflecting binary cylindrical lens and a Fresnel lens has been carried out.

EUSO-TA is a ground-based telescope, installed at the Telescope Array (TA) site in Black Rock Mesa, Utah, USA. This is the first detector to successfully use a Fresnel lens based optical system and multi-anode photomultipliers (64 channels per tube, 2304 channels encompassing a 10.6° × 10.6° field of view) for detection of Ultra High Energy Cosmic Rays (UHECR). The telescope is located in front of one of the fluorescence detectors of the TA experiment. Since its installation in 2013, the detector has observed several ultra-high energy cosmic ray events and, in addition, meteors. The limiting magnitude of 5.5 on summed frames (∼ 3 ms) has been established. Measurements of the UV night sky emission in different conditions and moon phases and positions have been completed. The performed observations serve as a proof of concept for the future application of this detector technology., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

In this paper, a Fresnel lens based high flux solar simulator (HFSS) is developed for concentrating solar power research and high temperature material testing. In this design, each commercially available 7 kW(e) xenon-arc lamp is coupled with a silicone-on-glass Fresnel lenses as the optical concentrator, and 12 lamp-lens units are distributed in a circular array. In total, the power of the solar simulator can reach 84 kWe. A ray tracing model has been developed based on the real arc-emitter shape and the Fresnel lens optics for predicting the optical performance of the HFSS design. The testing result shows that the ray tracing model can predict the flux distribution on the focal plane accurately but a bit conservative in the center region. The flux distribution on the focal plane appears axisymmetric with a peak flux of 7.22 MW/m(2), and 19.7 kW of radiative power in total is delivered on a 280 mm diameter target. (C) 2017 Elsevier Ltd. All rights reserved., QC 20170524

[EN] The focusing properties of Fresnel Zone Plates (FZPs) against frequency are analyzed in this work. It is shown that the FZP focal length depends almost linearly on the operating frequency. Focal depth and focal distortion are also considered, establishing a limit on the frequency span at which the operating frequency can be shifted. An underwater FZP ultrasound focusing system is demonstrated, and experimental results agree with the theoretical analysis and simulations.

[EN] The focusing capabilities of a pinhole zone plate lens are presented and compared with those of a conventional Fresnel zone plate lens. The focusing properties are examined both experimentally and numerically. The results confirm that a pinhole zone plate lens can be an alternative to a Fresnel lens. A smooth filtering effect is created in pinhole zone plate lenses, giving rise to a reduction of the side lobes around the principal focus associated with the conventional Fresnel zone plate lens. The manufacturing technique of the pinhole zone plate lens allows the designing and constructing of lenses for different focal lengths quickly and economically and without the need to drill new plates.

[EN] The focusing properties of Fresnel Zone Plates (FZPs) against frequency are analyzed in this work. It is shown that the FZP focal length depends almost linearly on the operating frequency. Focal depth and focal distortion are also considered, establishing a limit on the frequency span at which the operating frequency can be shifted. An underwater FZP ultrasound focusing system is demonstrated, and experimental results agree with the theoretical analysis and simulations.

Optical lighting systems usually demand specific illuminance distributions to comply with regulatory requirements for various applications. This study demonstrates an optical design of bicycle light integrated with a special Fresnel lens and a reflector. To enhance the light intensity, the proposed bicycle light adopts direct projection rather than reflection. The Fresnel lens is used to concentrate light and achieve the specific distribution of illuminance. The reflector provides a parabola reflective surface and reduces the divergence of light to greatly cast out parallel light, which improves the illuminance. For optimum case, the simulation is based on the total LED power of 180 lm, and the optical power is analyzed as 85 lm with a distance of 10 m away from the bicycle light. The illuminance distribution of bicycle light and cut-off line can meet the requirements of German StVZO regulations.

EUSO(Extreme Universe Space Observatory)は10(exp 20)eVを超える極限エネルギー宇宙線を検出するための科学ミッションである。それは宇宙線が地球大気中で作った空気シャワーからの紫外光を観測するこれまでにない超広視野(60度)の望遠鏡である。現在、日欧米の共同でEUSO計画を遂行中であり、将来国際宇宙ステーションに搭載を予定している。

Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Biomolecular and Pysical Sciences, Science, Environment, Engineering and Technology, The thesis describes the use of a high numerical aperture phase Fresnel lens for high resolution ion imaging and scalable fluorescence collection. We have demonstrated the first step towards fabricating and integrating a scalable collection optic with an ion trap with applications towards large scale ion trap quantum computers. I outline the use of the lens for capturing high resolution images of trapped ions. Using these high resolution images we have demonstrated spatial thermometry, a thermometry technique which relies on imaging the small changes in the ion spot size as the ion temperature changes. By adding a beam propagating along the optic axis of the imaging system we have also been able to use the high resolution imaging system to observe the absorption image from a single atom. We have verified that the contrast of the absorption images was the maximum achievable with our imaging system according to theory. Finally, using the absorption images we have been able to observe the phase shift of the light scattered by the atom with respect to the illumination field. The observed phase shift was found to be the maximum allowed by theory.

The thesis describes the use of a high numerical aperture phase Fresnel lens for high resolution ion imaging and scalable fluorescence collection. We have demonstrated the first step towards fabricating and integrating a scalable collection optic with an ion trap with applications towards large scale ion trap quantum computers. I outline the use of the lens for capturing high resolution images of trapped ions. Using these high resolution images we have demonstrated spatial thermometry, a thermometry technique which relies on imaging the small changes in the ion spot size as the ion temperature changes. By adding a beam propagating along the optic axis of the imaging system we have also been able to use the high resolution imaging system to observe the absorption image from a single atom. We have verified that the contrast of the absorption images was the maximum achievable with our imaging system according to theory. Finally, using the absorption images we have been able to observe the phase shift of the light scattered by the atom with respect to the illumination field. The observed phase shift was found to be the maximum allowed by theory., Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Biomolecular and Pysical Sciences, Science, Environment, Engineering and Technology, Full Text

Liquid crystal (LC) display and photonics devices based on photo-alignment and photo-patterning LC cells are developed. A fast switchable grating based on ferroelectric liquid crystals and orthogonal planar alignment by means of photo alignments. Both 1D and 2D gratings have been constructed. The proposed diffracting element provides fast response time of around 20 mu s, contrast of 7000: 1 and high diffraction efficiency, at the electric field of 6V/mu m. A switchable LC Fresnel zone lens was also developed with the efficiency of similar to 42% that can be further improved, and the switching time for the 3 mu m thick cell is similar to 6.7 ms which is relatively fast in comparison of existing devices. Thus, because of the photoalignment technology the fabrication of Fresnel lens became considerably simpler than others. A thin high spatial resolution, photo-patterned micropolarizer array for complementary metal-oxide-semiconductor (CMOS) image sensors was implemented for the complete optical visualization of so called

Liquid crystal (LC) display and photonics devices based on photo-alignment and photo-patterning LC cells are developed. A fast switchable grating based on ferroelectric liquid crystals and orthogonal planar alignment by means of photo alignments. Both 1D and 2D gratings have been constructed. The proposed diffracting element provides fast response time of around 20 mu s, contrast of 7000: 1 and high diffraction efficiency, at the electric field of 6V/mu m. A switchable LC Fresnel zone lens was also developed with the efficiency of similar to 42% that can be further improved, and the switching time for the 3 mu m thick cell is similar to 6.7 ms which is relatively fast in comparison of existing devices. Thus, because of the photoalignment technology the fabrication of Fresnel lens became considerably simpler than others. A thin high spatial resolution, photo-patterned micropolarizer array for complementary metal-oxide-semiconductor (CMOS) image sensors was implemented for the complete optical visualization of so called

PurposeEye growth compensates in opposite directions to single vision (SV) negative and positive lenses. We evaluated the response of the guinea pig eye to Fresnel-type lenses incorporating two different powers.MethodsA total of 114 guinea pigs (10 groups with 9-14 in each) wore a lens over one eye and interocular differences in refractive error and ocular dimensions were measured in each of three experiments. First, the effects of three Fresnel designs with various diopter (D) combinations (-5D/0D; +5D/0D or -5D/+5D dual power) were compared to three SV lenses (-5D, +5D, or 0D). Second, the ratio of -5D and +5D power in a Fresnel lens was varied (50:50 compared with 60:40). Third, myopia was induced by 4 days of exposure to a SV -5D lens, which was then exchanged for a Fresnel lens (-5D/+5D) or one of two SV lenses (+5D or -5D) and ocular parameters tracked for a further 3 weeks.ResultsDual power lenses induced an intermediate response between that to the two constituent powers (lenses +5D, +5D/0D, 0D, -5D/+5D, -5D/0D and -5D induced +2.1 D, +0.7 D, +0.1 D, -0.3 D, -1.6 D and -5.1 D in mean intraocular differences in refractive error, respectively), and changing the ratio of powers induced responses equal to their weighted average. In already myopic animals, continued treatment with SV negative lenses increased their myopia (from -3.3 D to -4.2 D), while switching to SV positive lenses or -5D/+5D Fresnel lenses reduced their myopia (by 2.9 D and 2.3 D, respectively).ConclusionsThe mammalian eye integrates competing defocus to guide its refractive development and eye growth. Fresnel lenses, incorporating positive or plano power with negative power, can slow ocular growth, suggesting that such designs may control myopia progression in humans.

Liquid crystal (LC) display and photonics devices based on photo-alignment and photo-patterning LC cells are developed. A fast switchable grating based on ferroelectric liquid crystals and orthogonal planar alignment by means of photo alignments. Both 1D and 2D gratings have been constructed. The proposed diffracting element provides fast response time of around 20 mu s, contrast of 7000: 1 and high diffraction efficiency, at the electric field of 6V/mu m. A switchable LC Fresnel zone lens was also developed with the efficiency of similar to 42% that can be further improved, and the switching time for the 3 mu m thick cell is similar to 6.7 ms which is relatively fast in comparison of existing devices. Thus, because of the photoalignment technology the fabrication of Fresnel lens became considerably simpler than others. A thin high spatial resolution, photo-patterned micropolarizer array for complementary metal-oxide-semiconductor (CMOS) image sensors was implemented for the complete optical visualization of so called

The dehydration process of gypsum rock was studied under concentrated solar energy by using a Fresnel lens with power density of 260 Wcm-2. Temperatures higher than 700¿C were attained for 1 min of solar exposure. The effect of grain size of sample and radiation exposure time on the formation of bassanite and anhydrite was studied by XRD. The complete transformation of dihydrate into hemihydrate and/or anhydrate phases is complete for the finer size sample. Plaster composed of 92.7% of anhydrite and 7.3% of bassanite was obtained for 5 min of solar exposure. Morphological and textural modifications were followed by SEM and interferometric/confocal profilometer.

A systematic design procedure for a high flux solar simulator is presented in this paper. The 84 kWe solar simulator is based on an array of 12 commercially available xenon-arc lamps (each 7 kWe) coupled with silicone-on-glass Fresnel lenses as the optical concentrator. A ray-tracing model of the xenon lamp has been developed based on the real emitter shape and the Fresnel lens optics; simulations performed using a non-sequential Monte Carlo technique have been validated against experimental test data. The results show that 19.7 kW of radiative power is delivered on a 20 cm diameter target with and a peak flux of 6.73 MW/m2 and an electricity to radiative power efficiency of 23.4%. This research facility will be used as an experimental platform for high flux solar receiver and thermochemical reactor research, as well as for advanced high-temperature material testing., QC 20140916

This work investigates the properties of off-axis focusing of prism-array lenses. Raytracing simulations are in agreement with measurements on a planar silicon prism-array lens at 13.4 keV. The simulations show that refractions and reflections on the paraxial side of the prisms cause scattering. This geometric scattering is the main impacting factor when focusing sources that are off the optical axis. For low-attenuating materials it also limits the effective aperture on axis. A new analytical model that is able to predict the amount of scattering is presented. Such a model is for example useful when optimising optical systems, but also to understand the limits and possibilities prism-array lenses., QC 20120809

In order to reduce the energy losses caused by shadow lines, three options are investigated. These are: 1. the use of two types of diodes; 2. the use of an ”ideal” diode based an active bypass by using MOS-FET’s [4] and 3. parallel switching of a number of cells between two shadow lines. The first method can reduce the voltage losses of the diode to about 300mV when oversized Schottky diodes are used. With the second method it is possible to reduce the voltage losses further to about 60mV for FETs with a resistance of 3m(omega). This method has as disadvantage that more electronic components are required to control the FET. With the third method about 10 cells are placed in parallel in one module. In that case only one shadow line appears on each module. Series connection of these parallel modules will result in zero energy losses because no bypass diodes are needed at all. This method has as a disadvantage of very high current output of the module of up to 200A. In a model, the three methods are further analyzed with respect of power losses and costs. The effect of the degree of shadowing on the daily energy yield and hence the fill factor is simulated with a model of the PV module. These results can be used in the design of the circuit of the ideal bypass diode.

Приведены результаты измерений диаграмм направленности и амплитудных распределений поля в области фокуса модифицированной линзы Френеля. Приводится сравнение с результатами расчетов основанных на решении интегрального уравнения для случая Е-поляризации.

In the patent the holographic apparatus and method uses a Fresnel lens as a scatter plate in data reduction holography. A second embodiment uses a Fresnel lens in series with a fly's eye lens array.

This procedure is a guide to be used by the Test Engineer, Field Service Representative or Test Officer for Shipboard testing the Fresnel Lens Optical Landing System MK 6 MOD 2 after initial installation or the completion of a major change, overhaul or extensive repairs. These tests are necessary to demonstrate the integrity of the installation as well as functional readiness for operation. (Author)

A marine lantern was recently introduced with a 300mm Fresnel acrylic plastic lens. Marine signal lanterns of this construction in 155mm and 250mm sizes have previously been photometrically tested and found to be more efficient than lanterns using pressed glass Fresnel lenses. A comparison test of all three acrylic plastic lenses is described herein. Photometric characteristics of the lanterns were measured using the same marine signal lamps and six-place lampchanger for all lanterns to afford direct comparison. (Author)

The constant glide slope power approach to landing is defined as establishing the airplane in the desired landing condition early in the landing maneuver and maintaining this condition to touchdown. Reasons for the U.S. Navy adopting this procedure are advance. The applicability of the procedure to non- carrier based fixed-wing airplanes is discussed. Various optical and electronic devices, including an approach power compensator, which can aid the pilot in executing the discussed procedure are fully described. The effectiveness of each device, integral or external to the airplane, in presenting airspeed, glide slope, line-up, bearing and range information to the pilot under VFR and IFR conditions is delineated., Presented at the Aircraft Take-Off and Landing Specialists' Meeting, sponsored by the AGARD Flight Mechanics Panel, 15-18 Jan 1963, Paris.

Předkládaná bakalářská práce se zabývá koncentrátorovými fotovoltaickými systémy. Je popsána historie jejich vzniku, vývoje a aplikace, princip činnosti a popis technologie konstrukcí, optiky, speciálních fotovoltaických článků a jejich chlazení. V praktické části je popsána konstrukce experimentálního koncentrátorového fotovoltaického systému postaveného u firmy Solartec s.r.o.. Tento systém slouží pro ověření hypotéz a studium chování systému za provozu. Cílem je změření reálných koncentračních, teplotních a elektrických vlastností systému a porovnání výhodnosti aktivního a pasivního chlazení článků., The subject of this bachelor´s thesis is to introduce concentrator photovoltaic systems, history of their foundation, evolution and application, principles of function and description of technology including its construction, optics, special photovoltaic cells and their cooling. The practical part of thesis describes the experimental concentrator photovoltaic system build in cooperation with Solartec s.r.o. company. The system is used to test hypotheses and study the behavior during its operation. The aim is to measure concentration ratio, temperature and electrical characteristics and to compare advantages of active and passive cooling of photovoltaic cells.

Bakalárska práca je zameraná na rozbor problematiky detekcie pohybu pomocou pasívneho infračerveného senzora. Pasívny infračervený senzor získava analógové hodnoty, ktoré sa prevádzajú pomocou analógovo-digitálneho prevodníka na digitálne dáta. Digitálne dáta sa následne vyhodnocujú prostredníctvom navrhnutého algoritmu. Prevod signálov zo senzora bol vykonaný pomocou platformy Arduino Leonardo, ktorá komunikuje s počítačom cez sériový port. Výsledný program vyhodnocuje pohyb podľa prahovej hodnoty získanej z vykonaných testov. Pri testoch bol senzor vystavený detekcii pohybu ľudí i pohybujúcich objektov. Práca taktiež skúma nové využitie senzora pohybu a uvádza namerané hodnoty pri vystavení senzora ohňu, ale i mrazu., The bachelor's thesis deals with analysis of motion detection through a passive infra-red sensor. The sensor obtains analogue data. Consequently, they are transferred via an analogue digital converter to digital data, which are then evaluated through the designed algorithm. The transmission of signals from the sensor was performed by Arduino Leonardo platform. It communicates with a personal computer via a serial port. The motion is evaluated in the final program according to the threshold figure which is acquired on the basis of the performed tests. In the course of the tests, the sensor was monitoring motion of people and moving objects. The thesis also examines new possibilities of usage of the sensor and it presents the measured data while exposing the sensor to fire and freeze.

V dnešní době se zvyšuje poptávka po součástkách, které jsou kvalitní a výkonné, ale zároveň co nejlehčí a nejlevnější. Tyto požadavky v optice splňují mikrooptické prvky. Cílem práce je navrhnout a vyrobit polymerní mikrooptický prvek pro korekci aberací spektroskopu typu Czerny-Turner, který byl zkonstruován na Ústavu přístrojové techniky AV ČR, v. v. i.. K návrhu byl použit software pro optické návrhy ZEMAX OpticStudio ver. 21. Výroba proběhla kombinací metod dvoufotonové polymerace a nanoimprintové litografie. Kvalita povrchu, profilu a kontrola vad byla provedena na konfokálním mikroskopu a na rastrovacím elektronovém mikroskopu. Funkce mikrooptického prvku byla otestována zakomponováním do zmíněného spektroskopu., There is a great demand nowadays for optical components with high quality and efficiency, yet as lightweight and low-priced as possible. These requirements are met by micro-optical elements. The aim of this work is to design and manufacture a polymer micro-optical element for aberration correction in a Czerny-Turner type spectroscope that had previously been constructed at the Institute of Scientific Instruments of the Czech Academy of Science. The design was carried out with the help of of the ZEMAX OpticStudio ver. 21 optical design software. The element was manufactured using the technique of two-photon polymeration and nanoimprint lithography. Surface quality, profile verification and presence of defects was checked using confocal microscopy and scanning electron microscopy. The micro-optical element was then successfully incorporated into the spectroscope.

Předkládaná bakalářská práce se zabývá koncentrátorovými fotovoltaickými systémy. Je popsána historie jejich vzniku, vývoje a aplikace, princip činnosti a popis technologie konstrukcí, optiky, speciálních fotovoltaických článků a jejich chlazení. V praktické části je popsána konstrukce experimentálního koncentrátorového fotovoltaického systému postaveného u firmy Solartec s.r.o.. Tento systém slouží pro ověření hypotéz a studium chování systému za provozu. Cílem je změření reálných koncentračních, teplotních a elektrických vlastností systému a porovnání výhodnosti aktivního a pasivního chlazení článků., The subject of this bachelor´s thesis is to introduce concentrator photovoltaic systems, history of their foundation, evolution and application, principles of function and description of technology including its construction, optics, special photovoltaic cells and their cooling. The practical part of thesis describes the experimental concentrator photovoltaic system build in cooperation with Solartec s.r.o. company. The system is used to test hypotheses and study the behavior during its operation. The aim is to measure concentration ratio, temperature and electrical characteristics and to compare advantages of active and passive cooling of photovoltaic cells.

Bakalárska práca je zameraná na rozbor problematiky detekcie pohybu pomocou pasívneho infračerveného senzora. Pasívny infračervený senzor získava analógové hodnoty, ktoré sa prevádzajú pomocou analógovo-digitálneho prevodníka na digitálne dáta. Digitálne dáta sa následne vyhodnocujú prostredníctvom navrhnutého algoritmu. Prevod signálov zo senzora bol vykonaný pomocou platformy Arduino Leonardo, ktorá komunikuje s počítačom cez sériový port. Výsledný program vyhodnocuje pohyb podľa prahovej hodnoty získanej z vykonaných testov. Pri testoch bol senzor vystavený detekcii pohybu ľudí i pohybujúcich objektov. Práca taktiež skúma nové využitie senzora pohybu a uvádza namerané hodnoty pri vystavení senzora ohňu, ale i mrazu., The bachelor's thesis deals with analysis of motion detection through a passive infra-red sensor. The sensor obtains analogue data. Consequently, they are transferred via an analogue digital converter to digital data, which are then evaluated through the designed algorithm. The transmission of signals from the sensor was performed by Arduino Leonardo platform. It communicates with a personal computer via a serial port. The motion is evaluated in the final program according to the threshold figure which is acquired on the basis of the performed tests. In the course of the tests, the sensor was monitoring motion of people and moving objects. The thesis also examines new possibilities of usage of the sensor and it presents the measured data while exposing the sensor to fire and freeze.

Diplomová práce se zabývá zhotovením funkčního headsetu pro konzumaci multimediálního obsahu. Nabyté teoretické znalosti byly využity při návrhu a sestavení výsledného headsetu. Teoretické znalosti byly utvrzeny a rozšířeny o praktické zkoušky na aktuálně dostupných komerčních řešeních AR/VR headsetů. Při praktickém návrhu bylo věnováno zvýšené úsilí o maximální možnou jednoduchost výsledného řešení. Komponenty, které byly při práci použité, lze získat relativně jednoduše přes internet. S pomocí pokročilých technik se práce snaží optimalizovat obrazový zážitek. Jsou vybrány nejvhodnější parametry optických čoček. Optická soustava je vylepšena tak, aby poskytovala rozšířené horizontální zorné pole. Práce se věnuje zhotovení headsetu metodou 3D tisku na 3D tiskárně. Následně jsou jednotlivé části složeny do jednoho funkčního celku. Výstupem diplomové práce je funkční prototyp headsetu vhodný pro konzumaci multimediálního obsahu., The thesis focuses on the construction of a functional headset for multimedia content consumption. The acquired theoretical knowledge was used in the design and construction of the resulting headset. The theoretical knowledge was consolidated and extended by practical tests on currently available commercial AR/VR headset solutions. In the practical design, increased effort was made to keep the resulting solution as simple as possible. The components that were used in the work can be obtained relatively easily via the internet. With the help of advanced techniques, the thesis tries to optimize the visual experience. The most suitable parameters of the optical lenses are selected. The optical system is enhanced to provide an extended horizontal field of view. The thesis discusses the fabrication of the headset using the 3D printing method on a 3D printer. Subsequently, the individual parts are assembled into a single functional unit. The result of the thesis is a working prototype headset suitable for multimedia content consumption.

V dnešní době se zvyšuje poptávka po součástkách, které jsou kvalitní a výkonné, ale zároveň co nejlehčí a nejlevnější. Tyto požadavky v optice splňují mikrooptické prvky. Cílem práce je navrhnout a vyrobit polymerní mikrooptický prvek pro korekci aberací spektroskopu typu Czerny-Turner, který byl zkonstruován na Ústavu přístrojové techniky AV ČR, v. v. i.. K návrhu byl použit software pro optické návrhy ZEMAX OpticStudio ver. 21. Výroba proběhla kombinací metod dvoufotonové polymerace a nanoimprintové litografie. Kvalita povrchu, profilu a kontrola vad byla provedena na konfokálním mikroskopu a na rastrovacím elektronovém mikroskopu. Funkce mikrooptického prvku byla otestována zakomponováním do zmíněného spektroskopu., There is a great demand nowadays for optical components with high quality and efficiency, yet as lightweight and low-priced as possible. These requirements are met by micro-optical elements. The aim of this work is to design and manufacture a polymer micro-optical element for aberration correction in a Czerny-Turner type spectroscope that had previously been constructed at the Institute of Scientific Instruments of the Czech Academy of Science. The design was carried out with the help of of the ZEMAX OpticStudio ver. 21 optical design software. The element was manufactured using the technique of two-photon polymeration and nanoimprint lithography. Surface quality, profile verification and presence of defects was checked using confocal microscopy and scanning electron microscopy. The micro-optical element was then successfully incorporated into the spectroscope.

Diplomová práce se zabývá zhotovením funkčního headsetu pro konzumaci multimediálního obsahu. Nabyté teoretické znalosti byly využity při návrhu a sestavení výsledného headsetu. Teoretické znalosti byly utvrzeny a rozšířeny o praktické zkoušky na aktuálně dostupných komerčních řešeních AR/VR headsetů. Při praktickém návrhu bylo věnováno zvýšené úsilí o maximální možnou jednoduchost výsledného řešení. Komponenty, které byly při práci použité, lze získat relativně jednoduše přes internet. S pomocí pokročilých technik se práce snaží optimalizovat obrazový zážitek. Jsou vybrány nejvhodnější parametry optických čoček. Optická soustava je vylepšena tak, aby poskytovala rozšířené horizontální zorné pole. Práce se věnuje zhotovení headsetu metodou 3D tisku na 3D tiskárně. Následně jsou jednotlivé části složeny do jednoho funkčního celku. Výstupem diplomové práce je funkční prototyp headsetu vhodný pro konzumaci multimediálního obsahu., The thesis focuses on the construction of a functional headset for multimedia content consumption. The acquired theoretical knowledge was used in the design and construction of the resulting headset. The theoretical knowledge was consolidated and extended by practical tests on currently available commercial AR/VR headset solutions. In the practical design, increased effort was made to keep the resulting solution as simple as possible. The components that were used in the work can be obtained relatively easily via the internet. With the help of advanced techniques, the thesis tries to optimize the visual experience. The most suitable parameters of the optical lenses are selected. The optical system is enhanced to provide an extended horizontal field of view. The thesis discusses the fabrication of the headset using the 3D printing method on a 3D printer. Subsequently, the individual parts are assembled into a single functional unit. The result of the thesis is a working prototype headset suitable for multimedia content consumption.

Předkládaná bakalářská práce se zabývá koncentrátorovými fotovoltaickými systémy. Je popsána historie jejich vzniku, vývoje a aplikace, princip činnosti a popis technologie konstrukcí, optiky, speciálních fotovoltaických článků a jejich chlazení. V praktické části je popsána konstrukce experimentálního koncentrátorového fotovoltaického systému postaveného u firmy Solartec s.r.o.. Tento systém slouží pro ověření hypotéz a studium chování systému za provozu. Cílem je změření reálných koncentračních, teplotních a elektrických vlastností systému a porovnání výhodnosti aktivního a pasivního chlazení článků., The subject of this bachelor´s thesis is to introduce concentrator photovoltaic systems, history of their foundation, evolution and application, principles of function and description of technology including its construction, optics, special photovoltaic cells and their cooling. The practical part of thesis describes the experimental concentrator photovoltaic system build in cooperation with Solartec s.r.o. company. The system is used to test hypotheses and study the behavior during its operation. The aim is to measure concentration ratio, temperature and electrical characteristics and to compare advantages of active and passive cooling of photovoltaic cells.

A Gallium Arsenide (GaAs) Solar Concentrator Array (SCA) was constructed using the recently developed fresnel lens technology. The parts used were a mixture of space qualified components and readily available off-the-shelf items. THe objective of the test to verify that the SCA would substantially increase the array's power output and reject the high thermal radiation it would encounter in space. It was found that the 3 by 3 GaAs SCA power output increased from 29.88 mW to 433.71 mW. The thermal analysis and the steady state cell operating temperature calculation showed that the SCA's thermal design would keep the GaAs solar cells at a steady state temperature of 50.7 C. However, because of the low intensity level of the light source available for use the cell operating temperature was only 27 C. This was considered to be inconclusive in determining the adequacy of the thermal design., http://archive.org/details/constructionofga1094522989, Major, United States Army, Approved for public release; distribution is unlimited.

Diplomová práce se zabývá zhotovením funkčního headsetu pro konzumaci multimediálního obsahu. Nabyté teoretické znalosti byly využity při návrhu a sestavení výsledného headsetu. Teoretické znalosti byly utvrzeny a rozšířeny o praktické zkoušky na aktuálně dostupných komerčních řešeních AR/VR headsetů. Při praktickém návrhu bylo věnováno zvýšené úsilí o maximální možnou jednoduchost výsledného řešení. Komponenty, které byly při práci použité, lze získat relativně jednoduše přes internet. S pomocí pokročilých technik se práce snaží optimalizovat obrazový zážitek. Jsou vybrány nejvhodnější parametry optických čoček. Optická soustava je vylepšena tak, aby poskytovala rozšířené horizontální zorné pole. Práce se věnuje zhotovení headsetu metodou 3D tisku na 3D tiskárně. Následně jsou jednotlivé části složeny do jednoho funkčního celku. Výstupem diplomové práce je funkční prototyp headsetu vhodný pro konzumaci multimediálního obsahu., The thesis focuses on the construction of a functional headset for multimedia content consumption. The acquired theoretical knowledge was used in the design and construction of the resulting headset. The theoretical knowledge was consolidated and extended by practical tests on currently available commercial AR/VR headset solutions. In the practical design, increased effort was made to keep the resulting solution as simple as possible. The components that were used in the work can be obtained relatively easily via the internet. With the help of advanced techniques, the thesis tries to optimize the visual experience. The most suitable parameters of the optical lenses are selected. The optical system is enhanced to provide an extended horizontal field of view. The thesis discusses the fabrication of the headset using the 3D printing method on a 3D printer. Subsequently, the individual parts are assembled into a single functional unit. The result of the thesis is a working prototype headset suitable for multimedia content consumption.