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Optical Manufacturing
Optical manufacturing and testing is the process of manufacturing and testing optical components. It spans a wide range of manufacturing procedures and optical test configurations. The manufacture of a conventional spherical lens typically begins with the generation of the optic's rough shape by grinding a glass blank. This can be done, for example, with ring tools. Next, the lens surface is polished to its final form. Typically this is done by lapping—rotating and rubbing the rough lens surface against a tool with the desired surface shape, with a mixture of abrasives and fluid in between. Typically a carved pitch tool is used to polish the surface of a lens. The mixture of abrasive is called slurry and it is typically made from cerium or zirconium oxide in water with lubricants added to facilitate pitch tool movement without sticking to the lens. The particle size in the slurry is adjusted to get the desired shape and finish. Types of lapping include planetary lapping, d ... [...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] |
Polishing
Polishing is the process of creating a smooth and shiny surface by rubbing it or by applying a chemical treatment, leaving a clean surface with a significant specular reflection (still limited by the index of refraction of the material according to the Fresnel equations). In some materials (such as metals, glasses, black or transparent stones), polishing is also able to reduce diffuse reflection to minimal values. When an unpolished surface is magnified thousands of times, it usually looks like a succession of mountains and valleys. By repeated abrasion, those "mountains" are worn down until they are flat or just small "hills". The process of polishing with abrasives starts with a coarse grain size and gradually proceeds to the finer ones to efficiently flatten the surface imperfections and to obtain optimal results. Mechanical properties The strength of polished products can be higher than their unpolished counterparts owing to the removal of stress concentrations pres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Selenide
Zinc selenide is the inorganic compound with the formula ZnSe. It is a lemon-yellow solid although most samples have a duller color due to the effects of oxidation. It is an intrinsic semiconductor with a band gap of about 2.70 eV at , equivalent to a wavelength of 459 nm. ZnSe occurs as the rare mineral stilleite, named after Hans Stille. Synthesis and properties ZnSe is available in both hexagonal (wurtzite) and cubic (zincblende) polymorphs. In both cases, the Zn2+ and Se2− sites are tetrahedral. The difference in the structures related to close packing motifs, hexagonal vs cubic. Cubic ZnSe is produced by treatment of an aqueous solution of zinc sulfate with hydrogen selenide: : Heating the cubic form gives hexagonal ZnSe. An alternative synthesis involves heating a mixture of zinc oxide, zinc sulfide, and selenium: : It is a wide-bandgap semiconductor of the II-VI semiconductor group (since zinc and selenium belong to the 12th and 16th groups of the periodic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Fluoride
Calcium fluoride is the inorganic compound of the elements calcium and fluorine with the formula CaF2. It is a white solid that is practically insoluble in water. It occurs as the mineral fluorite (also called fluorspar), which is often deeply coloured owing to impurities. Chemical structure The compound crystallizes in a cubic motif called the fluorite structure. Ca2+ centres are eight-coordinate, being centred in a cube of eight F− centres. Each F− centre is coordinated to four Ca2+ centres in the shape of a tetrahedron. Although perfectly packed crystalline samples are colorless, the mineral is often deeply colored due to the presence of F-centers. The same crystal structure is found in numerous ionic compounds with formula AB2, such as CeO2, cubic ZrO2, UO2, ThO2, and PuO2. In the corresponding anti-structure, called the antifluorite structure, anions and cations are swapped, such as Be2C. Gas phase The gas phase is noteworthy for failing the predictions of VSEP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon
Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Silicon is a significant element that is essential for several physiological and metabolic processes in plants. Silicon is widely regarded as the predominant semiconductor material due to its versatile applications in various electrical devices such as transistors, solar cells, integrated circuits, and others. These may be due to its significant band gap, expansive optical transmission range, extensive absorption spectrum, surface roughening, and effective anti-reflection coating. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fused Silica
Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO2) in amorphous (non-crystalline) form. This differs from all other commercial glasses, such as soda-lime glass, lead glass, or borosilicate glass, in which other ingredients are added which change the glasses' optical and physical properties, such as lowering the melt temperature, the spectral transmission range, or the mechanical strength. Fused quartz, therefore, has high working and melting temperatures, making it difficult to form and less desirable for most common applications, but is much stronger, more chemically resistant, and exhibits lower thermal expansion, making it more suitable for many specialized uses such as lighting and scientific applications. The terms ''fused quartz'' and ''fused silica'' are used interchangeably but can refer to different manufacturing techniques, resulting in different trace impurities. However fused quartz, being in the glassy st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colloidal Silica
Colloidal silicas are suspensions of fine amorphous, nonporous, and typically spherical silica particles in a liquid phase. It may be produced by Stöber process from Tetraethyl orthosilicate (TEOS). Properties Usually they are suspended in an aqueous phase that is stabilized electrostatically. Colloidal silicas exhibit particle densities in the range of 2.1 to 2.3 g/cm3. Most colloidal silicas are prepared as monodisperse suspensions with particle sizes ranging from approximately 30 to 100 nm in diameter. Polydisperse suspensions can also be synthesized and have roughly the same limits in particle size. Smaller particles are difficult to stabilize while particles much greater than 150 nanometers are subject to sedimentation. Manufacture Colloidal silicas are most often prepared in a multi-step process where an alkali-silicate solution is partially neutralized, leading to the formation of silica nuclei. The subunits of colloidal silica particles are typically in the rang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerium(IV) Oxide
Cerium(IV) oxide, also known as ceric oxide, ceric dioxide, ceria, cerium oxide or cerium dioxide, is an oxide of the rare-earth metal cerium. It is a pale yellow-white powder with the chemical formula CeO2. It is an important commercial product and an intermediate in the purification of the element from the ores. The distinctive property of this material is its reversible conversion to a Non-stoichiometric compound, non-stoichiometric oxide. Production Cerium occurs naturally as oxides, always as a mixture with other rare-earth elements. Its principal ores are bastnaesite and monazite. After extraction of the metal ions into aqueous base, Ce is separated from that mixture by addition of an oxidant followed by adjustment of the pH. This step exploits the low solubility of CeO2 and the fact that other rare-earth elements resist oxidation.. Cerium(IV) oxide is formed by the calcination of cerium oxalate or cerium hydroxide. Cerium also forms cerium(III) oxide, , which is unst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Carbide
Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A wide bandgap semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal since 1893 for use as an abrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Large single crystals of silicon carbide can be grown by the Lely method and they can be cut into gems known as synthetic moissanite. Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and Cat's whisker detector, detectors in early radios were first demonstrated around 1907. SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both. Natural occurrence Naturally occurring moissanite is found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Oxide
Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula . It is the most commonly occurring of several Aluminium oxide (compounds), aluminium oxides, and specifically identified as aluminium oxide. It is commonly called alumina and may also be called aloxide, aloxite, ALOX or alundum in various forms and applications and alumina is refined from bauxite. It occurs naturally in its crystalline Polymorphism (materials science), polymorphic phase (matter), phase α-Al2O3 as the mineral corundum, varieties of which form the precious gemstones ruby and sapphire,which have an alumina content approaching 100%. Al2O3 is used as feedstock to produce aluminium metal, as an abrasive owing to its hardness, and as a refractory material owing to its high melting point. Natural occurrence Corundum is the most common naturally occurring crystallinity, crystalline form of aluminium oxide. ruby, Rubies and sapphires are gem-quality forms o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetorheological Finishing
Magnetorheological finishing (MRF) is a precision surface finishing technology. Optical surfaces are polished in a computer-controlled magnetorheological (MR) finishing slurry. Unlike conventional rigid lap polishing, the MR fluid's shape and stiffness can be magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...ically manipulated and controlled in real time. The optic's final surface form and finishing results are predicted through the use of computer algorithms. General references * W.I. Kordonski (2014).Magnetorheological Fluid-Based High Precision Finishing Technology" Magnetorheology: Advances and Applications, Norman M. Wereley, Ed., RSC Smart Materials, Cambridge, UK, Chapter 11, 261–277. * Chunlin Miao, et al.,Shear stress in magnetorheological finishing for gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-point Diamond Turning
Diamond turning is turning using a cutting tool with a diamond tip. It is a process of mechanical machining of precision elements using lathes or derivative machine tools (e.g., turn-mills, rotary transfers) equipped with natural or synthetic diamond-tipped tool bits. The term single-point diamond turning (SPDT) is sometimes applied, although as with other lathe work, the "single-point" label is sometimes only nominal (radiused tool noses and contoured form tools being options). The process of diamond turning is widely used to manufacture high-quality aspheric optical elements from crystals, metals, acrylic, and other materials. Plastic optics are frequently molded using diamond turned mold inserts. Optical elements produced by the means of diamond turning are used in optical assemblies in telescopes, video projectors, missile guidance systems, lasers, scientific research instruments, and numerous other systems and devices. Most SPDT today is done with computer numerical control (CN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
