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Surface Imperfections (optics)
Surface imperfections on optical surfaces such as lenses or mirrors, can be caused during the manufacturing of the part or handling. These imperfections are part of the surface and cannot be removed by cleaning. Surface quality is characterized either by the American military standard notation (eg "60-40") or by specifying RMS (root mean square) roughness (eg "0.3 nm RMS"). American notation focuses on how visible surface defects are, and is a "cosmetic" specification. RMS notation is an objective measurable property of the surface. Tighter specifications increase the costs of fabricating optical elements but looser ones affect performance. While surface imperfections can be labeled "cosmetic defects", they are not purely cosmetic. Optics for laser applications are more sensitive to surface quality as any imperfections can lead to laser-induced damage. In some cases, imperfections in optical elements will be directly imaged as defects in the image plane. Optical systems requiring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Four Mirrors - Dielectric Aluminum Silver And Chrome
4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is a square number, the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures. Evolution of the Hindu-Arabic digit Brahmic numerals represented 1, 2, and 3 with as many lines. 4 was simplified by joining its four lines into a cross that looks like the modern plus sign. The Shunga would add a horizontal line on top of the digit, and the Kshatrapa and Pallava evolved the digit to a point where the speed of writing was a secondary concern. The Arabs' 4 still had the early concept of the cross, but for the sake of efficiency, was made in one stroke by connecting the "western" end to the "northern" end; the "eastern" end was finished off with a curve. The Europeans dropped the finishing curve and gradually made the digit less cursive, ending up with a digit very close to the original Brahmin cross. While the shape of the character fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kodak
The Eastman Kodak Company, referred to simply as Kodak (), is an American public company that produces various products related to its historic basis in film photography. The company is headquartered in Rochester, New York, and is incorporated in New Jersey. It is best known for photographic film products, which it brought to a mass market for the first time. Kodak began as a partnership between George Eastman and Henry A. Strong to develop a film roll camera. After the release of the Kodak camera, Eastman Kodak was incorporated on May 23, 1892. Under Eastman's direction, the company became one of the world's largest film and camera manufacturers, and also developed a model of welfare capitalism and a close relationship with the city of Rochester. During most of the 20th century, Kodak held a dominant position in photographic film, and produced a number of technological innovations through heavy investment in research and development at Kodak Research Laboratories. Kodak produce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of optical instruments, instruments that use or Photodetector, detect it. Optics usually describes the behaviour of visible light, visible, ultraviolet, and infrared light. Light is a type of electromagnetic radiation, and other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the Classical electromagnetism, classical electromagnetic description of light, however complete electromagnetic descriptions of light are often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of Ray (optics), rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Inspection
Visual inspection is a common method of quality control, data acquisition, and data analysis. Visual Inspection, used in maintenance of facilities, mean inspection of equipment and structures using either or all of raw human senses such as vision, hearing, touch and smell and/or any non-specialized inspection equipment. Inspections requiring Ultrasonic, X-Ray equipment, Infrared, etc. are not typically regarded as visual inspection as these Inspection methodologies require specialized equipment, training and certification. Quality control A study of the visual inspection of small integrated circuits found that the modal duration of eye fixations of trained inspectors was about 200 ms. The most accurate inspectors made the fewest eye fixations and were the fastest. When the same chip was judged more than once by an individual inspector the consistency of judgment was very high whereas the consistency between inspectors was somewhat less. Variation by a factor of six in inspectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Control
Quality control (QC) is a process by which entities review the quality of all factors involved in production. ISO 9000 defines quality control as "a part of quality management focused on fulfilling quality requirements". This approach places emphasis on three aspects (enshrined in standards such as ISO 9001): # Elements such as controls, job management, defined and well managed processes, performance and integrity criteria, and identification of records # Competence, such as knowledge, skills, experience, and qualifications # Soft elements, such as personnel, integrity, confidence, organizational culture, motivation, team spirit, and quality relationships. Inspection is a major component of quality control, where physical product is examined visually (or the end results of a service are analyzed). Product inspectors will be provided with lists and descriptions of unacceptable product defects such as cracks or surface blemishes for example. History and introductio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scattering From Rough Surfaces
Surface roughness scattering or interface roughness scattering is the elastic scattering of particles against a rough solid surface or imperfect interface between two different materials. This effect has been observed in classical systems, such as microparticle scattering, as well as quantum systems, where it arises electronic devices, such as field effect transistors and quantum cascade lasers. Classical description In the classical mechanics framework, a rough surface, such as a machined metal surface, randomizes the probability distribution function governing the incoming particles, leading to net momentum loss of the particle flux. Quantum description In the quantum mechanical framework, this scattering is most noticeable in confined systems, in which the energies for charge carriers are determined by the locations of interfaces. An example of such a system is a quantum well, which may be constructed from a sandwich of different layers of semiconductor. Variations in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Roughness
Surface roughness or simply roughness is the quality of a surface of not being smooth and it is hence linked to human ( haptic) perception of the surface texture. From a mathematical perspective it is related to the spatial variability structure of surfaces, and inherently it is a multiscale property. It has different interpretations and definitions depending on the disciplines considered. In surface metrology, surface roughness is a component of surface finish (surface texture). It is quantified by the deviations in the direction of the normal vector of a real surface from its ideal form. If these deviations are large, the surface is rough; if they are small, the surface is smooth. Roughness is typically assumed to be the high-frequency, short-wavelength component of a measured surface. However, in practice it is often necessary to know both the amplitude and frequency to ensure that a surface is fit for a purpose. Role and effect Roughness plays an important role in determin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ra Parameter
Ra is the Sun-god of Ancient Egypt. Ra or RA may also refer to: Arts and entertainment Film and television * Ra (Stargate), a character from the film ''Stargate'', based on the Egyptian god * ''Ra'' (1972 film), a 1972 documentary film about Thor Heyerdahl's expeditions * ''Ra'' (2014 film), a Tamil fantasy film Gaming * ''Rocket Arena'', a ''Quake'' mod * '' Command & Conquer: Red Alert'', a game Music * A half-step below Re on the solfège musical scale Performers * Ra (band), an American rock band * Ra (musician), the pseudonym of Raoul Sinier, a French digital painter and electronic musician * R.A. the Rugged Man (born c. 1974), American rapper * Sun Ra (1914–1993), American jazz musician and philosopher * Rise Against, an American punk/hardcore band Albums * ''Ra'' (Utopia album), 1977 * ''Ra'' (Eloy album), 1988 Songs * "Ra", a song by Northlane from ''Node'', 2015 * Ra (Inna song), 2018 Other media * ''Ra'', a novel by qntm * Ra (board game), a board game ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
