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Opaque Projector
The opaque projector, or episcope is a device which displays opaque materials by shining a bright lamp onto the object from above. The episcope must be distinguished from the diascope, which is a projector used for projecting images of transparent objects (such as films), and from the epidiascope, which is capable of projecting images of both opaque and transparent objects. A system of mirrors, prisms and/or imaging lenses is used to focus an image of the material onto a viewing screen. Because they must project the reflected light, opaque projectors require brighter bulbs and larger lenses than overhead projectors. Care must be taken that the materials are not damaged by the heat generated by the light source. Opaque projectors are not as common as the overhead projector. Opaque projectors are typically used to project images of book pages, drawings, mineral specimens, leaves, etc. They have been produced and marketed as artists' enlargement tools to allow images to be transfer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Episcope , used in armoured fighting vehicles
{{Disambiguation ...
Episcope may refer to: *Opaque projector *Episcopal polity, within various Christian Churches and in ecumenical dialogue *Episcope, an indirect-vision device similar to a periscope A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limelight
Limelight (also known as Drummond light or calcium light)James R. Smith (2004). ''San Francisco's Lost Landmarks'', Quill Driver Books. is a non-electric type of stage lighting that was once used in theatres and music halls. An intense illumination is created when a flame fed by oxygen and hydrogen is directed at a cylinder of quicklime (calcium oxide), due to a combination of incandescence and candoluminescence. Although it has long since been replaced by electric lighting, the term has nonetheless survived, as someone in the public eye is still said to be "in the limelight". The actual lamps are called "limes", a term which has been transferred to electrical equivalents. History Discovery and invention The limelight effect was discovered in the 1820s by Goldsworthy Gurney, based on his work with the "oxy-hydrogen blowpipe", credit for which is normally given to Robert Hare. In 1825, a Scottish engineer, Thomas Drummond (1797–1840), saw a demonstration of the effect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telop
A TELOP (TELevision OPtical Slide Projector) was the trademark name of a multifunction, four-channel "project-all" slide projector developed by the Gray Research & Development Company for television usage, introduced in 1949. It was best remembered in the industry as an opaque slide projector for title cards. Before Telop In the early days of television, there were two types of slides for broadcast—a ''transparent slide'' or transparency, and an ''opaque'' slide, or ''Balop'' (a genericized trademark of Bausch & Lomb's Balopticon projectors). Transparency slides were prepared as 2-inch square cards mounted in cardboard or glass, or film, surrounded by a half-inch of masking on all four sides. Opaque, "Balop" slides were cards on stock or larger (always maintaining the 4:3 aspect ratio) that were photographed by the use of a Balopticon. Opaque cards were popular as shooting a card on a stand often caused keystoning problems. A fixed size and axis would ensure no geometr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projector (other)
A projector is a device that projects an image on a surface. Projector may also refer to: Computing * Projector PSA, a software and cloud-computing company * Projector, a version control system used in the Macintosh Programmer's Workshop Weaponry * Projector, a type of mortar ** Livens Projector ** PIAT (Projector, Infantry, Anti Tank), British Second World War spigot mortar * Holman Projector * Northover Projector The Projector, 2.5 inch—more commonly known as the Northover Projector—was an ''ad hoc'' anti-tank weapon used by the British Army and British Home Guard, Home Guard during the Second World War. With a Operation Sealion, German invasion ... Other uses * Projector (business) * ''Projector'' (Dark Tranquillity album), 1999 * Projector (Geese album), 2021 * Projector (patent), the original inventor to reduce an invention to practice * In mathematics, a projection operator * The Projector, a Singaporean cinema chain See also * Corporate promoter or pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camera Lucida
A ''camera lucida'' is an optical device used as a drawing aid by artists and microscopy, microscopists. It projects an optics, optical superimposition of the subject being viewed onto the surface upon which the artist is drawing. The artist sees both scene and drawing surface simultaneously, as in a photographic double exposure. This allows the artist to duplicate key points of the scene on the drawing surface, thus aiding in the accurate rendering of perspective. History The ''camera lucida'' was patented in 1806 by the English chemist William Hyde Wollaston. The basic optics were described 200 years earlier by the German astronomer Johannes Kepler in his ''Dioptrice'' (1611), but there is no evidence he constructed a working ''camera lucida''. There is also evidence to suggest that the Elizabethan spy Arthur Gregory's 1596 "perspective box" operated on at least highly similar principles to the later ''camera lucida'', but the secretive nature of his work and fear of rivals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video Camera
A video camera is an optical instrument that captures videos, as opposed to a movie camera, which records images on film. Video cameras were initially developed for the television industry but have since become widely used for a variety of other purposes. Video cameras are used primarily in two modes. The first, characteristic of much early broadcasting, is live television, where the camera feeds real time images directly to a screen for immediate observation. A few cameras still serve live television production, but most live connections are for security, military/tactical, and industrial operations where surreptitious or remote viewing is required. In the second mode the images are recorded to a storage device for archiving or further processing; for many years, videotape was the primary format used for this purpose, but was gradually supplanted by optical disc, hard disk, and then flash memory. Recorded video is used in television production, and more often surveillance and m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Document Camera
A document camera, also known as a visual presenter, visualizer, digital overhead, docu-cam, or simply a doc-cam, is a Image resolution, high-resolution image capture device used to display objects in real-time to a large audience, such as in a classroom or lecture hall. It can also function as an alternative to a traditional image scanner for digitizing documents for archival or digital storage. The camera is typically mounted on an adjustable arm, allowing it to be positioned over a document or object. It connects to a projector or similar video display system, enabling the presenter to display text, images, or an object to the audience. Larger objects can be placed in front of the camera, which can then be rotated as needed. Use cases Document cameras are used in various settings, including: * Lecture halls and classrooms. * Presentations in Conference, conferences, Meeting, meetings, and training sessions. * Videoconferencing and telepresence. * Presentation of evidence in Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halogen Lamp
A halogen lamp (also called tungsten halogen, quartz-halogen, and quartz iodine lamp) is an incandescent lamp consisting of a tungsten filament sealed in a compact transparent envelope that is filled with a mixture of an inert gas and a small amount of a halogen, such as iodine or bromine. The combination of the halogen gas and the tungsten filament produces a halogen-cycle chemical reaction, which redeposits evaporated tungsten on the filament, increasing its life and maintaining the clarity of the envelope. This allows the filament to operate at a higher temperature than a standard incandescent lamp of similar power and operating life; this also produces light with higher luminous efficacy and color temperature. The small size of halogen lamps permits their use in compact optical systems for projectors and illumination. The small glass envelope may be enclosed in a much larger outer glass bulb, which has a lower temperature, protects the inner bulb from contamination, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incandescent Light Bulb
An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a #Filament, filament until it incandescence, glows. The filament is enclosed in a glass bulb that is either vacuum, evacuated or filled with inert gas to protect the filament from oxidation. Electric current is supplied to the filament by terminals or wires embedded in the glass. A bulb socket provides mechanical support and electrical connections. Incandescent bulbs are manufactured in a wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. They require no external Regulator (automatic control), regulating equipment, have low manufacturing costs, and work equally well on either alternating current or direct current. As a result, the incandescent bulb became widely used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, and flashlights, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
François-Napoléon-Marie Moigno
Abbé François-Napoléon-Marie Moigno (; 15 April 1804 – 14 July 1884) was a French Catholic priest and one time Jesuit, as well as a physicist and author. He considered himself a student of Cauchy. Life Moigno was born at Guémené-sur-Scorff, Morbihan, in Brittany, on 15 April 1804. He received his early education at the Jesuit college at Sainte-Anne-d'Auray and entered the novitiate of the Society of Jesus on 2 September 1822. He did his theology, theological studies at Montrouge, devoting his leisure to mathematics and physics. On the outbreak of the July Revolution, Revolution of 1830, he left with his fellow Jesuits for Brig, Switzerland, Brieg in Switzerland. There he acquired several languages, including Hebrew language, Hebrew and Arabic language, Arabic. In 1836 he was appointed professor of mathematics at the College of Sainte-Geneviève, Rue des Postes, in Paris. Here he became known not only as a scholar, but also as a preacher and writer. He wrote numerous artic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (optics)
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), usually arranged along a common axis. Lenses are made from materials such as glass or plastic and are ground, polished, or molded to the required shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called "lenses", such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses. Lenses are used in various imaging devices such as telescopes, binoculars, and cameras. They are also used as visual aids in glasses to correct defects of vision such as myopia and hypermetropia. History The word ''lens'' comes from , the Latin name of the lentil (a seed of a lentil pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxyhydrogen
Oxyhydrogen is a mixture of hydrogen (H2) and oxygen (O2) gases. This gaseous mixture is used for torches to process refractory materials and was the first gaseous mixture used for welding. Theoretically, a ratio of 2:1 hydrogen:oxygen is enough to achieve maximum efficiency; in practice a ratio 4:1 or 5:1 is needed to avoid an oxidizing flame. This mixture may also be referred to as ' (Scandinavian and German '; ), although some authors define knallgas to be a generic term for the mixture of fuel with the precise amount of oxygen required for complete combustion, thus 2:1 oxyhydrogen would be called "hydrogen-knallgas". "Brown's gas" and HHO are terms for oxyhydrogen originating in pseudoscience, although is preferred due to meaning . Properties Oxyhydrogen will combust when brought to its autoignition temperature. For the stoichiometric mixture in air, at normal atmospheric pressure, autoignition occurs at about 570 °C (1065 °F). The minimum energy requi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
