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Etendue
Etendue or étendue (; ) is a property of light in an optical system, which characterizes how "spread out" the light is in area and angle. It corresponds to the beam parameter product (BPP) in Gaussian beam optics. Other names for etendue include acceptance, throughput, light grasp, light-gathering power, optical extent, and the AΩ product. ''Throughput'' and ''AΩ product'' are especially used in radiometry and radiative transfer where it is related to the view factor (or shape factor). It is a central concept in nonimaging optics. From the source point of view, etendue is the product of the area of the source and the solid angle that the system's entrance pupil subtends as seen from the source. Equivalently, from the system point of view, the etendue equals the area of the entrance pupil times the solid angle the source subtends as seen from the pupil. These definitions must be applied for infinitesimally small "elements" of area and solid angle, which must then b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etendue For Differential Surface Element In 2D And 3D
Etendue or étendue (; ) is a property of light in an optics, optical system, which characterizes how "spread out" the light is in area and angle. It corresponds to the beam parameter product (BPP) in Gaussian beam optics. Other names for etendue include acceptance, throughput, light grasp, light-gathering power, optical extent, and the AΩ product. ''Throughput'' and ''AΩ product'' are especially used in radiometry and radiative transfer where it is related to the view factor (or shape factor). It is a central concept in nonimaging optics. From the source point of view, etendue is the product of the area of the source and the solid angle that the system's entrance pupil subtends as seen from the source. Equivalently, from the system point of view, the etendue equals the area of the entrance pupil times the solid angle the source subtends as seen from the pupil. These definitions must be applied for infinitesimally small "elements" of area and solid angle, which must th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etendue In Refraction
Etendue or étendue (; ) is a property of light in an optical system, which characterizes how "spread out" the light is in area and angle. It corresponds to the beam parameter product (BPP) in Gaussian beam optics. Other names for etendue include acceptance, throughput, light grasp, light-gathering power, optical extent, and the AΩ product. ''Throughput'' and ''AΩ product'' are especially used in radiometry and radiative transfer where it is related to the view factor (or shape factor). It is a central concept in nonimaging optics. From the source point of view, etendue is the product of the area of the source and the solid angle that the system's entrance pupil subtends as seen from the source. Equivalently, from the system point of view, the etendue equals the area of the entrance pupil times the solid angle the source subtends as seen from the pupil. These definitions must be applied for infinitesimally small "elements" of area and solid angle, which must then be su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etendue
Etendue or étendue (; ) is a property of light in an optical system, which characterizes how "spread out" the light is in area and angle. It corresponds to the beam parameter product (BPP) in Gaussian beam optics. Other names for etendue include acceptance, throughput, light grasp, light-gathering power, optical extent, and the AΩ product. ''Throughput'' and ''AΩ product'' are especially used in radiometry and radiative transfer where it is related to the view factor (or shape factor). It is a central concept in nonimaging optics. From the source point of view, etendue is the product of the area of the source and the solid angle that the system's entrance pupil subtends as seen from the source. Equivalently, from the system point of view, the etendue equals the area of the entrance pupil times the solid angle the source subtends as seen from the pupil. These definitions must be applied for infinitesimally small "elements" of area and solid angle, which must then b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamiltonian Optics
Hamiltonian opticsH. A. Buchdahl, ''An Introduction to Hamiltonian Optics'', Dover Publications, 1993, . and Lagrangian opticsVasudevan Lakshminarayanan et al., ''Lagrangian Optics'', Springer Netherlands, 2011, . are two formulations of geometrical optics which share much of the mathematical formalism with Hamiltonian mechanics and Lagrangian mechanics. Hamilton's principle In physics, Hamilton's principle states that the evolution of a system \left(q_1,\dots,q_N\right) described by N generalized coordinates between two specified states at two specified parameters ''σ''''A'' and ''σ''''B'' is a stationary point (a point where the variation is zero) of the action functional, or \delta S= \delta\int_^ L\left(q_1,\cdots,q_N,\dot_1,\cdots,\dot_N,\sigma\right)\, d\sigma=0 where \dot_k=dq_k/d\sigma and L is the Lagrangian. Condition \delta S=0 is valid if and only if the Euler-Lagrange equations are satisfied, i.e., \frac - \frac\frac = 0 with k = 1, \dots, N. The momentum is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonimaging Optics
Nonimaging optics (also called anidolic optics)Roland Winston et al., ''Nonimaging Optics'', Academic Press, 2004 R. John Koshel (Editor), ''Illumination Engineering: Design with Nonimaging Optics'', Wiley, 2013 is a branch of optics that is concerned with the optimal transfer of light radiation between a source and a target. Unlike traditional imaging optics, the techniques involved do not attempt to form an image of the source; instead an optimized optical system for optimal radiative transfer from a source to a target is desired. Applications The two design problems that nonimaging optics solves better than imaging optics are: * solar energy concentration: maximizing the amount of energy applied to a receiver, typically a solar cell or a thermal receiver * illumination: controlling the distribution of light, typically so it is "evenly" spread over some areas and completely blocked from other areas Typical variables to be optimized at the target include the total radiant flux, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conservation Of Etendue
Conservation is the preservation or efficient use of resources, or the conservation of various quantities under physical laws. Conservation may also refer to: Environment and natural resources * Nature conservation, the protection and management of the environment and natural resources **Wetland conservation, protecting and preserving areas where water exists at or near the Earth's surface, such as swamps, marshes and bogs. * Conservation biology, the science of protection and management of biodiversity * Conservation movement, political, environmental, or social movement that seeks to protect natural resources, including biodiversity and habitat * Conservation organization, an organization dedicated to protection and management of the environment or natural resources * Wildlife conservation, the practice of protecting wild species and their habitats in order to prevent species from going extinct * ''Conservation'' (magazine), published by the Society for Conservation Biolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
View Factor
Acornsoft was the software arm of Acorn Computers, and a major publisher of software for the BBC Micro and Acorn Electron. As well as games, it also produced a large number of educational titles, extra computer languages and business and utility packages – these included word processor ''VIEW'' and the spreadsheet '' ViewSheet'' supplied on ROM and cartridge for the BBC Micro/ Acorn Electron and included as standard in the BBC Master and Acorn Business Computer. History Acornsoft was formed in late 1980 by Acorn Computers directors Hermann Hauser and Chris Curry, and David Johnson-Davies, author of the first game for a UK personal computer and of the official Acorn Atom manual "Atomic Theory and Practice". David Johnson-Davies was managing director and in early 1981 was joined by Tim Dobson, Programmer and Chris Jordan, Publications Editor. While some of their games were clones or remakes of popular arcade games (e.g. ''Hopper'' is a clone of Sega's '' Frogger'', '' S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second Law Of Thermodynamics
The second law of thermodynamics is a physical law based on Universal (metaphysics), universal empirical observation concerning heat and Energy transformation, energy interconversions. A simple statement of the law is that heat always flows spontaneously from hotter to colder regions of matter (or 'downhill' in terms of the temperature gradient). Another statement is: "Not all heat can be converted into Work (thermodynamics), work in a cyclic process."Young, H. D; Freedman, R. A. (2004). ''University Physics'', 11th edition. Pearson. p. 764. The second law of thermodynamics establishes the concept of entropy as a physical property of a thermodynamic system. It predicts whether processes are forbidden despite obeying the requirement of conservation of energy as expressed in the first law of thermodynamics and provides necessary criteria for spontaneous processes. For example, the first law allows the process of a cup falling off a table and breaking on the floor, as well as allowi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entropy
Entropy is a scientific concept, most commonly associated with states of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynamics, where it was first recognized, to the microscopic description of nature in statistical physics, and to the principles of information theory. It has found far-ranging applications in chemistry and physics, in biological systems and their relation to life, in cosmology, economics, sociology, weather science, climate change and information systems including the transmission of information in telecommunication. Entropy is central to the second law of thermodynamics, which states that the entropy of an isolated system left to spontaneous evolution cannot decrease with time. As a result, isolated systems evolve toward thermodynamic equilibrium, where the entropy is highest. A consequence of the second law of thermodynamics is that certain processes are irreversible. The thermodynami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffuser (optics)
In optics, a diffuser (also called a light diffuser or optical diffuser) is any material that diffuses or scatters light in some manner to transmit soft light. Diffused light can be easily obtained by reflecting light from a white surface, while more compact diffusers may use translucent material, including ground glass, teflon, opal glass, and greyed glass. Types Perfect reflecting diffuser A perfect (reflecting) diffuser (PRD) is a theoretical perfectly white surface with Lambertian reflectance (its brightness appears the same from any angle of view). It does not absorb light, giving back 100% of the light it receives. Reflective diffusers can be easily characterised by scatterometers.{{cite web, url=http://www.zebraoptical.com/roughnessviascatterometry.html, title=Page Title, website=www.zebraoptical.com Diffractive diffuser/homogenizer A diffractive diffuser is a kind of diffractive optical element (DOE) that exploits the principles of diffraction and refraction. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wikibooks
Wikibooks (previously called ''Wikimedia Free Textbook Project'' and ''Wikimedia-Textbooks'') is a wiki-based Wikimedia project hosted by the Wikimedia Foundation for the creation of free content digital textbooks and annotated texts that anyone can edit. Initially, the project was created solely in English in July 2003; a later expansion to include additional languages was started in July 2004. As of , there are Wikibooks sites active for languages Wikimedia's MediaWiki API:Sitematrix. Retrieved from Data:Wikipedia statistics/meta.tab comprising a total of articles and recently active editors. Wikimedia's MediaWiki API:Siteinfo. Retrieved from Data:Wikipedia statistics/data.tab History The wikibooks.org domain was registered on July 19, 2003. It was launched to host and build free textbooks on subjects such as organic chemistry and physics, in response to a request by Wikipedia contributor Karl Wick. Two major sub-projects, Wikijunior and Wikiversity, were creat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transparency (optics)
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable light scattering by particles, scattering of light. On a macroscopic scale (one in which the dimensions are much larger than the wavelengths of the photons in question), the photons can be said to follow Snell's law. Translucency (also called translucence or translucidity) is the physical property of allowing light to pass through the material (with or without scattering of light). It allows light to pass through but the light does not necessarily follow Snell's law on the macroscopic scale; the photons may be scattered at either of the two interfaces, or internally, where there is a change in the index of refraction. In other words, a translucent material is made up of components with different indices of refraction. A transparent material is made up of components with a uniform index of refraction. Transparent m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
