Download or read book Comparison of Computational Modeling of Precision Glass Molding of Infrared Lenses written by Mohamad Amin Moghaddas and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of manufacturing process of an infrared lens by using a commercial glass molding machine, GP-10000HT, is the second step to figure out all the details of a real precision glass molding process that help us to provide a simulation that makes a better prediction of glass molding process.
Download or read book Investigation of Optical Effects of Chalcogenide Glass in Precision Glass Molding and Applications on Infrared Micro Optical Manufacturing written by Lin Zhang and published by . This book was released on 2019 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precision glass molding (PGM) is being considered as an alternative to traditional methods of manufacturing large-volume, high-quality and low-cost optical components. In this process, glass optics is fabricated by replicating optical features from precision molds to glass at elevated temperature. Chalcogenide glasses are emerging as alternative infrared materials for their wide range infrared transmission, high refractive index and low phonon energy. In addition, chalcogenide glasses can be readily molded into precision optics at elevated temperature, slightly above its glass transition temperature (Tg), which in general is much lower compared to oxide glasses. The primary goal of this research is to evaluate the thermoforming mechanism of chalcogenide glass around Tg and investigate its refractive index change and residual stresses in molded lens in and post PGM. Firstly, a constitutive model is introduced to precisely predict the material behavior in PGM by integrating subroutines into a commercial finite element method (FEM) software. This modeling approach utilizes the Williams-Landel-Ferry (WLF) equation and Tool-Narayanaswamy-Moynihan (TNM) model to describe (shear) stress relaxation and structural relaxation behaviors, respectively. It is predicted that `index drop’ occurred inside the molded prism due to rapid thermal cycling and the cooling rate above Tg can introduce large geometry deviations to the molded optical lens. Secondly, the refractive index variations inside molded lenses are further evaluated by measuring deviation angle through a prism & wavefront changes through molded lens using a Shack-Hartmann wavefront sensor (SHS), while the residual stresses trapped inside the molded lenses are obtained by using a birefringence method. Measured results of the molded infrared lenses combining numerical simulation provide an opportunity for optical manufacturers to achieve a better understanding of the mechanism and optical performance variation of chalcogenide glasses in and post PGM. Upon completion of the aforementioned research, two typical micro IR optics are designed, fabricated and tested, an infrared SHS and a large field-of-view (FOV) microlens array, as demonstrations. A novel fabrication method combining virtual spindle based high-speed single-point diamond milling and PGM process is adopted to fabricate infrared microlens array. The uniqueness of the virtual spindle based single-point diamond milling is that the surface features can be constructed sequentially by spacing the virtual spindle axis at an arbitrary position based on a combination of rotational and transitional motions of the machine tool. After the mold insert is machined, it is employed to replicate the optical profile onto chalcogenide glass. On the other hand, an infrared compound-eye system consisting of 3×3 channels for a FOV of 48°×48° is developed. The freeform microlens array on a flat surface is utilized to steer and focus the incident light from all three dimensions (3D) to a two-dimension (2D) infrared imager. Using raytracing, the profiles of the freeform microlenses of each channel are optimized to obtain the best imaging performance. To avoid crosstalk among adjacent channels, a micro aperture array fabricated by 3D printing is mounted between the microlens array and IR imager. The imaging tests of the infrared compound-eye imaging system show that the asymmetrical freeform lenslets are capable of steering and forming legible images within the design FOV. Compared to a conventional infrared camera, this novel microlens array can achieve a considerably larger FOV while maintaining low manufacturing cost without sacrificing image quality. Finally, two rapid heating processes are explored and demonstrated by using graphene-coated silicon as an effective and high-performance mold material for precision glass molding. One process is based on induction heating and the other one is based on mid-infrared radiation. Since the graphene coating is very thin (~45 nm), a high heating rate of 5~20 °C/s can be achieved. The contact surface of the Si mold and the polymer substrate can be heated above the Tg within 20 s and subsequently cooled down to room temperature within tens of seconds after molding. The feasibility of this process is validated by the fabrication of optical gratings, micropillar matrices, and microlens arrays on polymethylmethacrylate (PMMA) substrate with high precision. The uniformity and surface geometries of the replicated optical elements are evaluated using an optical profilometer. Compared with conventional bulk heating molding process, this novel rapid localized heating process could improve replication efficiency with better geometrical fidelity.
Download or read book Advances in Optics Vol 3 written by Sergey Yurish and published by Lulu.com. This book was released on 2018-04-26 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Advances in Optics: Reviews' Book Series is a comprehensive study of the field of optics, which provides readers with the most up-to-date coverage of optics, photonics and lasers with a good balance of practical and theoretical aspects. Directed towards both physicists and engineers this Book Series is also suitable for audiences focusing on applications of optics. The Vol.3 is devoted to various topics of applied optics and contains 17 chapters written by 49 experts in the field from 14 countries: Australia, China, India, Israel, Italy, Japan, Malaysia, Mexico, The Netherlands, Poland, Taiwan, UK, USA, Vietnam A clear comprehensive presentation makes these books work well as both a teaching resources and a reference books. The book is intended for researchers and scientists in physics and optics, in academia and industry, as well as postgraduate students.
Download or read book Japanese Technical Abstracts written by and published by . This book was released on 1988 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molded Optics written by Michael Schaub and published by CRC Press. This book was released on 2016-04-19 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: While several available texts discuss molded plastic optics, none provide information on all classes of molded optics. Filling this gap, Molded Optics: Design and Manufacture presents detailed descriptions of molded plastic, glass, and infrared optics. Since an understanding of the manufacturing process is necessary to develop cost-effective, produ
Download or read book Harnessing Light written by National Research Council and published by National Academies Press. This book was released on 1998-09-25 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical science and engineering affect almost every aspect of our lives. Millions of miles of optical fiber carry voice and data signals around the world. Lasers are used in surgery of the retina, kidneys, and heart. New high-efficiency light sources promise dramatic reductions in electricity consumption. Night-vision equipment and satellite surveillance are changing how wars are fought. Industry uses optical methods in everything from the production of computer chips to the construction of tunnels. Harnessing Light surveys this multitude of applications, as well as the status of the optics industry and of research and education in optics, and identifies actions that could enhance the field's contributions to society and facilitate its continued technical development.
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1972 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Microfabrication and Precision Engineering written by J. Paulo Davim and published by Woodhead Publishing. This book was released on 2016-11-19 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microfabrication and precision engineering is an increasingly important area relating to metallic, polymers, ceramics, composites, biomaterials and complex materials. Micro-electro-mechanical-systems (MEMS) emphasize miniaturization in both electronic and mechanical components. Microsystem products may be classified by application, and have been applied to a variety of fields, including medical, automotive, aerospace and alternative energy. Microsystems technology refers to the products as well as the fabrication technologies used in production. With detailed information on modelling of micro and nano-scale cutting, as well as innovative machining strategies involved in microelectrochemical applications, microchannel fabrication, as well as underwater pulsed Laser beam cutting, among other techniques, Microfabrication and Precision Engineering is a valuable reference for students, researchers and professionals in the microfabrication and precision engineering fields. Contains contributions by top industry experts Includes the latest techniques and strategies Special emphasis given to state-of-the art research and development in microfabrication and precision engineering
Download or read book Glassy Materials Based Microdevices written by Giancarlo C. Righini and published by MDPI. This book was released on 2019-02-28 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microtechnology has changed our world since the last century, when silicon microelectronics revolutionized sensor, control and communication areas, with applications extending from domotics to automotive, and from security to biomedicine. The present century, however, is also seeing an accelerating pace of innovation in glassy materials; as an example, glass-ceramics, which successfully combine the properties of an amorphous matrix with those of micro- or nano-crystals, offer a very high flexibility of design to chemists, physicists and engineers, who can conceive and implement advanced microdevices. In a very similar way, the synthesis of glassy polymers in a very wide range of chemical structures offers unprecedented potential of applications. The contemporary availability of microfabrication technologies, such as direct laser writing or 3D printing, which add to the most common processes (deposition, lithography and etching), facilitates the development of novel or advanced microdevices based on glassy materials. Biochemical and biomedical sensors, especially with the lab-on-a-chip target, are one of the most evident proofs of the success of this material platform. Other applications have also emerged in environment, food, and chemical industries. The present Special Issue of Micromachines aims at reviewing the current state-of-the-art and presenting perspectives of further development. Contributions related to the technologies, glassy materials, design and fabrication processes, characterization, and, eventually, applications are welcome.
Download or read book Physics Briefs written by and published by . This book was released on 1989 with total page 910 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1987 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications Reports and Papers for 1961 from Oak Ridge National Laboratory written by Oak Ridge National Laboratory and published by . This book was released on 1965 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Near Infrared Spectroscopy and Related Computational Methods written by Christian Huck and published by MDPI. This book was released on 2020-01-03 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last few decades, near-infrared (NIR) spectroscopy has distinguished itself as one of the most rapidly advancing spectroscopic techniques. Mainly known as an analytical tool useful for sample characterization and content quantification, NIR spectroscopy is essential in various other fields, e.g. NIR imaging techniques in biophotonics, medical applications or used for characterization of food products. Its contribution in basic science and physical chemistry should be noted as well, e.g. in exploration of the nature of molecular vibrations or intermolecular interactions. One of the current development trends involves the miniaturization and simplification of instrumentation, creating prospects for the spread of NIR spectrometers at a consumer level in the form of smartphone attachments—a breakthrough not yet accomplished by any other analytical technique. A growing diversity in the related methods and applications has led to a dispersion of these contributions among disparate scientific communities. The aim of this Special Issue was to bring together the communities that may perceive NIR spectroscopy from different perspectives. It resulted in 30 contributions presenting the latest advances in the methodologies essential in near-infrared spectroscopy in a variety of applications.
Download or read book Applied Predictive Modeling written by Max Kuhn and published by Springer Science & Business Media. This book was released on 2013-05-17 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applied Predictive Modeling covers the overall predictive modeling process, beginning with the crucial steps of data preprocessing, data splitting and foundations of model tuning. The text then provides intuitive explanations of numerous common and modern regression and classification techniques, always with an emphasis on illustrating and solving real data problems. The text illustrates all parts of the modeling process through many hands-on, real-life examples, and every chapter contains extensive R code for each step of the process. This multi-purpose text can be used as an introduction to predictive models and the overall modeling process, a practitioner’s reference handbook, or as a text for advanced undergraduate or graduate level predictive modeling courses. To that end, each chapter contains problem sets to help solidify the covered concepts and uses data available in the book’s R package. This text is intended for a broad audience as both an introduction to predictive models as well as a guide to applying them. Non-mathematical readers will appreciate the intuitive explanations of the techniques while an emphasis on problem-solving with real data across a wide variety of applications will aid practitioners who wish to extend their expertise. Readers should have knowledge of basic statistical ideas, such as correlation and linear regression analysis. While the text is biased against complex equations, a mathematical background is needed for advanced topics.
Download or read book Computational Photography written by Ramesh Raskar and published by A K Peters/CRC Press. This book was released on 2016-05-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Photography combines plentiful computing, digital sensors, modern optics, actuators, probes, and smart lights to escape the limitations of traditional film cameras and enables novel imaging applications. This book provides a practical guide to topics in image capture and manipulation methods for generating compelling pictures for graphics, special effects, scene comprehension, and art. The computational techniques discussed cover topics in exploiting new ideas in manipulating optics, illumination, and sensors at time of capture. In addition, the authors describe sophisticated reconstruction procedures from direct and indirect pixel measurements that go well beyond the traditional digital darkroom experience.
Download or read book Engineered Materials Abstracts written by and published by . This book was released on 1989 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
