1.
Nixie tube
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A Nixie tube, or cold cathode display, is an electronic device for displaying numerals or other information using glow discharge. The glass tube contains a wire-mesh anode and multiple cathodes, shaped like numerals or other symbols, applying power to one cathode surrounds it with an orange glow discharge. The tube is filled with a gas at low pressure, usually mostly neon and often a little mercury or argon, although it resembles a vacuum tube in appearance, its operation does not depend on thermionic emission of electrons from a heated cathode. It is therefore called a tube, or a variant of neon lamp. Such tubes rarely exceed 40 °C even under the most severe of operating conditions in a room at ambient temperature, the early Nixie displays were made by a small vacuum tube manufacturer called Haydu Brothers Laboratories, and introduced in 1955 by Burroughs Corporation, who purchased Haydu. The name Nixie was derived by Burroughs from NIX I, an abbreviation of Numeric Indicator eXperimental No,1, although this may have been a backronym designed to evoke a mythical creature. Hundreds of variations of design were manufactured by many firms. The Burroughs Corporation introduced Nixie and owned the name Nixie as a trademark, nixie-like displays made by other firms had trademarked names including Digitron, Inditron and Numicator. A proper generic term is cold cathode neon readout tube, though the phrase Nixie tube quickly entered the vernacular as a generic name, Burroughs even had another Haydu tube that could operate as a digital counter and directly drive a Nixie tube for display. This was called a Trochotron, in later form known as the Beam-X Switch counter tube, another name was magnetron beam-switching tube, trochotrons were used in the UNIVAC1101 computer, as well as in clocks and frequency counters. The first trochotrons were surrounded by a cylindrical magnet, with poles at the ends. The field inside the magnet had essentially-parallel lines of force, parallel to the axis of the tube and it was a thermionic vacuum tube, inside were a central cathode, ten anodes, and ten spade electrodes. The magnetic field and voltages applied to the made the electrons form a thick sheet that went to only one anode. Applying a pulse with specified width and voltages to the made the sheet advance to the next anode. A later form of trochotron called a Beam-X Switch replaced the large, glow-transfer counting tubes, similar in essential function to the trochotrons, had a glow discharge on one of a number of main cathodes, visible through the top of the glass envelope. Sets of guide cathodes between the indicating cathodes moved the glow in steps to the main cathode. Types with two or three sets of guide cathodes could count in either direction, a well-known trade name for glow-transfer counter tubes in the United Kingdom was Dekatron. Types with connections to each individual indicating cathode, which enabled presetting the tubes state to any value, were trade named Selectron tubes, however, their construction was cruder, their average lifetime was shorter, and they failed to find many applications due to their complex periphery
2.
LED
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A light-emitting diode is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated, when a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light is determined by the band gap of the semiconductor. LEDs are typically small and integrated optical components may be used to shape the radiation pattern, appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are still used as transmitting elements in remote-control circuits. The first visible-light LEDs were also of low intensity and limited to red, modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness. Early LEDs were often used as indicator lamps for electronic devices and they were soon packaged into numeric readouts in the form of seven-segment displays and were commonly seen in digital clocks. Recent developments in LEDs permit them to be used in environmental, LEDs have allowed new displays and sensors to be developed, while their high switching rates are also used in advanced communications technology. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Light-emitting diodes are now used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, as of 2017, LED lights home room lighting are as cheap or cheaper than compact fluorescent lamp sources of comparable output. They are also more energy efficient and, arguably, have fewer environmental concerns linked to their disposal. Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide, russian inventor Oleg Losev reported creation of the first LED in 1927. His research was distributed in Soviet, German and British scientific journals, rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide and other semiconductor alloys in 1955. Braunstein observed infrared emission generated by simple diode structures using gallium antimonide, GaAs, indium phosphide, in 1957, Braunstein further demonstrated that the rudimentary devices could be used for non-radio communication across a short distance. As noted by Kroemer Braunstein …had set up a simple optical communications link, the emitted light was detected by a PbS diode some distance away. This signal was fed into an amplifier and played back by a loudspeaker. Intercepting the beam stopped the music and we had a great deal of fun playing with this setup. This setup presaged the use of LEDs for optical communication applications, by October 1961, they had demonstrated efficient light emission and signal coupling between a GaAs p-n junction light emitter and an electrically-isolated semiconductor photodetector
3.
Vacuum fluorescent display
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A vacuum fluorescent display is a display device used commonly on consumer-electronics equipment such as video cassette recorders, car radios, and microwave ovens. Sometimes named as ice tube indicator, a VFD operates on the principle of cathodoluminescence, roughly similar to a cathode ray tube, but operating at much lower voltages. Each tube in a VFD has a phosphor coated anode that is bombarded by electrons emitted from the cathode filament, in fact, each tube in VFD is a triode vacuum tube because it also has a mesh control grid. Unlike liquid crystal displays, a VFD emits a bright light with high contrast. Cadmium was commonly used in VFDs in the past, but the current RoHS-compliant VFDs have eliminated this metal from their construction, VFDs can display seven-segment numerals, multi-segment alpha-numeric characters or can be made in a dot-matrix to display different alphanumeric characters and symbols. In practice, there is little limit to the shape of the image that can be displayed, the first VFD was the single indication DM160 by Philips in 1959. The first multi-segment VFD was the 1962 Japanese single-digit, seven-segment device, the displays became common on calculators and other consumer electronics devices. In the late 1980s hundreds of millions of units were made yearly, the device consists of a hot cathode, anodes and grids encased in a glass envelope under a high vacuum condition. The cathode is made up of fine wires, coated by alkaline earth metal oxides. These electrons are controlled and diffused by the grids, which are made up of thin metal, if electrons impinge on the phosphor-coated plates, they fluoresce, emitting light. Unlike the orange-glowing cathodes of traditional vacuum tubes, VFD cathodes are efficient emitters at much lower temperatures, the principle of operation is identical to that of a vacuum tube triode. Electrons can only reach a given plate element if both the grid and the plate are at a potential with respect to the cathode. This allows the displays to be organized as multiplexed displays where the grids and plates form a matrix. In the example of the VCR display shown to the right, all of the similar plates in all of the digits are connected in parallel. One by one, the microprocessor driving the display enables a digit by placing a positive voltage on that digits grid, electrons flow through that digits grid and strike those plates that are at a positive potential. The microprocessor cycles through illuminating the digits in this way at a high enough to create the illusion of all digits glowing at once via persistence of vision. Several amateurs have experimented with the possibilities of using VFDs as triodes, the extra indicators are arranged as if they were segments of an additional digit or two or extra segments of existing digits and are scanned using the same multiplexed strategy as the real digits. Some of these extra indicators may use a phosphor that emits a different colour of light, for example, orange
4.
Output device
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An output device is any piece of computer hardware item which utilizes whatever data and commands from your computer in order to perform a task. This leads to the results of data processing carried out by a processing system which converts the electronically generated information into human-readable form. A display device is a device that visually conveys text, graphics. Information shown on a device is called soft copy because the information exists electronically and is displayed for a temporary period of time. Display devices include CRT monitors, LCD monitors and displays, gas plasma monitors, there are many input and output devices such as multi function printers and computer-based navigation systems that are used for specialized or unique applications. In computing, input/output refers to the communication between an information processing system, and the outside world, inputs are the signals or data received by the system, and outputs are the signals or data sent from it. Some types of output are text, graphics, tactile, audio, text consists of characters that are used to create words, sentences, and paragraphs. Graphics are digital representations of information such as drawings, charts, photographs. Tactile output such as raised line drawings may be useful for individuals who are blind. Audio is music, speech, or any other sound, video consists of images played back at speeds to provide the appearance of full motion. A digital image is a representation of an image stored on a computer. They dont have any size until they are displayed on a screen or printed on paper. Until that point, they are just a collection of numbers on the hard drive that describe the individual elements of a picture. Some computers come with graphics capability of. Others need a device, called a card or graphics adapter board. Unless a computer has graphics capability built into the motherboard, that takes place on the graphics card. Depending on whether the resolution is fixed, it may be of vector or raster type. Without qualifications, the digital image usually refers to raster images also called bitmap images
5.
Information
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In other words, it is the answer to a question of some kind. It is thus related to data and knowledge, as data represents values attributed to parameters, as it regards data, the informations existence is not necessarily coupled to an observer, while in the case of knowledge, the information requires a cognitive observer. At its most fundamental, information is any propagation of cause, Information can be encoded into various forms for transmission and interpretation. It can also be encrypted for safe storage and communication, the uncertainty of an event is measured by its probability of occurrence and is inversely proportional to that. The more uncertain an event, the information is required to resolve uncertainty of that event. The bit is a unit of information, but other units such as the nat may be used. Example, information in one fair coin flip, log2 =1 bit, the concept that information is the message has different meanings in different contexts. The English word was derived from the Latin stem of the nominative. Inform itself comes from the Latin verb informare, which means to give form, eidos can also be associated with thought, proposition, or even concept. The ancient Greek word for information is πληροφορία, which transliterates from πλήρης fully and it literally means fully bears or conveys fully. In modern Greek language the word Πληροφορία is still in use and has the same meaning as the word information in English. In addition to its meaning, the word Πληροφορία as a symbol has deep roots in Aristotles semiotic triangle. In this regard it can be interpreted to communicate information to the one decoding that specific type of sign, from the stance of information theory, information is taken as an ordered sequence of symbols from an alphabet, say an input alphabet χ, and an output alphabet ϒ. Information processing consists of a function that maps any input sequence from χ into an output sequence from ϒ. The mapping may be probabilistic or deterministic and it may have memory or be memoryless. Often information can be viewed as a type of input to an organism or system, inputs are of two kinds, some inputs are important to the function of the organism or system by themselves. In his book Sensory Ecology Dusenbery called these causal inputs, other inputs are important only because they are associated with causal inputs and can be used to predict the occurrence of a causal input at a later time. Some information is important because of association with information but eventually there must be a connection to a causal input
6.
Visual system
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The visual system is the part of the central nervous system which gives organisms the ability to process visual detail, as well as enabling the formation of several non-image photo response functions. It detects and interprets information from visible light to build a representation of the surrounding environment, the psychological process of visual information is known as visual perception, a lack of which is called blindness. Non-image forming visual functions, independent of perception, include the pupillary light reflex. This article mostly describes the system of mammals, humans in particular. Together the cornea and lens refract light into a small image, the retina transcribes this image into electrical pulses using rods and cones. The optic nerve then carries these pulses through the optic canal, upon reaching the optic chiasm the nerve fibers decussate. The fibers then branch and terminate in three places, most end in the lateral geniculate nucleus. Before the LGN forwards the pulses to V1 of the visual cortex it gauges the range of objects, the LGN also sends some fibers to V2 and V3. V1 performs edge-detection to understand spatial organization, V2 both forwards pulses to V1 and receives them. Pulvinar is responsible for saccade and visual attention, V2 serves much the same function as V1, however, it also handles illusory contours, determining depth by comparing left and right pulses, and foreground distinguishment. V3 helps process ‘global motion’ of objects, V3 connects to V1, V2, and the inferior temporal cortex. V4 recognizes simple shapes, gets input from V1, V2, V3, LGN, v5’s outputs include V4 and its surrounding area, and eye-movement motor cortices. V5’s functionality is similar to that of the other V’s, however, V6 works in conjunction with V5 on motion analysis. V5 analyzes self-motion, whereas V6 analyzes motion of objects relative to the background, v6’s primary input is V1, with V5 additions. V6 houses the topographical map for vision, V6 outputs to the region directly around it. V6A has direct connections to arm-moving cortices, including the premotor cortex, the inferior temporal gyrus recognizes complex shapes, objects, and faces or, in conjunction with the hippocampus, creates new memories. The pretectal area is seven unique nuclei, anterior, posterior and medial pretectal nuclei inhibit pain, aid in REM, and aid the accommodation reflex, respectively. The Edinger-Westphal nucleus moderates pupil dilation and aids in convergence of the eyes, nuclei of the optic tract are involved in smooth pursuit eye movement and the accommodation reflex, as well as REM
7.
Somatosensory system
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The somatosensory system is a part of the sensory nervous system. The somatosensory system is a system of sensory neurons and pathways that responds to changes at the surface or inside the body. The axons, of sensory neurons connect with, or respond to, sensory receptors are found all over the body including the skin, epithelial tissues, muscles, bones and joints, internal organs, and the cardiovascular system. Somatic senses are sometimes referred to as somesthetic senses, with the understanding that somesthesis includes the sense of touch, proprioception, the mapping of the body surfaces in the brain is called a cortical homunculus and plays a fundamental role in the creation of body image. This brain-surface map is not immutable, however, dramatic shifts can occur in response to stroke or injury. The four mechanoreceptors in the skin respond to different stimuli for short or long periods. Merkel cell nerve endings are found in the epidermis and hair follicles, they react to low vibrations. Due to a receptive field they are used in areas like fingertips the most, they are not covered. Tactile corpuscles react to moderate vibration and light touch and they are located in the dermal papillae, due to their reactivity they are primarily located in fingertips and lips. They respond in quick action potentials, unlike Merkel and they are responsible for the ability to read Braille and feel gentle stimuli. Lamellar corpuscles determine gross touch and distinguish rough and soft substances and they react in quick action potentials, especially to vibrations around 250 Hz. They are the most sensitive to vibrations, and have large receptor fields, pacinian reacts only to sudden stimuli so pressures like clothes that are always compressing their shape are quickly ignored. Bulbous corpuscles react slowly and respond to sustained skin stretch and they are responsible for the feeling of object slippage and play a major role in the kinesthetic sense and control of finger position and movement. Merkel and bulbous cells are myelinated, the rest are not, all of these receptors are activated upon pressures that squish their shape causing an action potential. All afferent touch/vibration info ascends the spinal cord via the posterior column-medial lemniscus pathway via gracilis or cuneatus, cuneatus sends signals to the cochlear nucleus indirectly via spinal grey matter, this info is used in determining if a perceived sound is just villi noise/irritation. All fibers cross in the medulla, the postcentral gyrus includes the primary somatosensory cortex collectively referred to as S1. BA3 receives the densest projections from the thalamus, bA3a is involved with the sense of relative position of neighboring body parts and amount of effort being used during movement. BA3b is responsible for distributing somato info, it projects texture info to BA1, region S2 divides into Area S2 and parietal ventral area
8.
Refreshable braille display
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A refreshable braille display or braille terminal is an electro-mechanical device for displaying braille characters, usually by means of round-tipped pins raised through holes in a flat surface. Blind computer users who use a computer monitor can use it to read text output. Speech synthesizers are also used for the same task. Deafblind computer users may also use refreshable braille displays, the base of a refreshable braille display often integrates a pure braille keyboard. Other variants exist that use a conventional QWERTY keyboard for input and braille pins for output, on some models the position of the cursor is represented by vibrating the dots, and some models have a switch associated with each cell to move the cursor to that cell directly. The mechanism which raises the dots uses the effect of some crystals. Such a crystal is connected to a lever, which in turn raises the dot, there has to be a crystal for each dot of the display, i. e. eight per character. Because of the complexity of producing a reliable display that will cope with daily wear and tear, usually, only 40 or 80 braille cells are displayed. Models with between 18 and 40 cells exist in some notetaker devices, the software that controls the display is called a screen reader. It gathers the content of the screen from the system, converts it into braille characters. Screen readers for graphical operating systems are complex, because graphical elements like windows or slidebars have to be interpreted and described in text form. A rotating-wheel Braille display was developed in 2000 by the National Institute of Standards and Technology, both wheels are still in the process of commercialization. In these units, braille dots are put on the edge of a spinning wheel, the braille dots are set in a simple scanning-style fashion as the dots on the wheel spin past a stationary actuator that sets the braille characters. As a result, manufacturing complexity is reduced and rotating-wheel braille displays. Designs for a full braille computer monitor have been patented but not yet produced, a full page braille display with 1,000 cells was developed in 2015 by the Tactisplay Corp. With total 12,000 pixels configured in 120*100, it can show any BANA compatible braille graphic page in 8 seconds and this video shows operation of the device. Tactile is a real-time text-to-braille translation device currently under development at the Massachusetts Institute of Technology, GNOME accessibility NIST, Converting Digital Information to Braille at the Wayback Machine Information on Bi-directional Refreshable Tactile Display US Patent 6,692,255
9.
Television
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Television or TV is a telecommunication medium used for transmitting moving images in monochrome, or in color, and in two or three dimensions and sound. The term can refer to a set, a television program. Television is a medium for entertainment, education, news, politics, gossip. Television became available in experimental forms in the late 1920s. After World War II, a form of black-and-white TV broadcasting became popular in the United States and Britain, and television sets became commonplace in homes, businesses. During the 1950s, television was the medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in the US, for many reasons, the storage of television and video programming now occurs on the cloud. At the end of the first decade of the 2000s, digital television transmissions greatly increased in popularity, another development was the move from standard-definition television to high-definition television, which provides a resolution that is substantially higher. HDTV may be transmitted in various formats, 1080p, 1080i, in 2013, 79% of the worlds households owned a television set. Most TV sets sold in the 2000s were flat-panel, mainly LEDs, major manufacturers announced the discontinuation of CRT, DLP, plasma, and even fluorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are gradually expected to be replaced by OLEDs, also, major manufacturers have announced that they will increasingly produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s, Television signals were initially distributed only as terrestrial television using high-powered radio-frequency transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by cable or optical fiber, satellite systems and. Until the early 2000s, these were transmitted as analog signals, a standard television set is composed of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is correctly called a video monitor rather than a television, the word television comes from Ancient Greek τῆλε, meaning far, and Latin visio, meaning sight. The Anglicised version of the term is first attested in 1907 and it was. formed in English or borrowed from French télévision. In the 19th century and early 20th century, other. proposals for the name of a technology for sending pictures over distance were telephote. The abbreviation TV is from 1948, the use of the term to mean a television set dates from 1941
10.
Computer monitor
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A computer monitor or a computer display is an electronic visual display for computers. A monitor usually comprises the display device, circuitry, casing, the display device in modern monitors is typically a thin film transistor liquid crystal display or a flat panel LED display, while older monitors used a cathode ray tubes. It can be connected to the computer via VGA, DVI, HDMI, DisplayPort, Thunderbolt, LVDS or other proprietary connectors, originally, computer monitors were used for data processing while television receivers were used for entertainment. From the 1980s onwards, computers have used for both data processing and entertainment, while televisions have implemented some computer functionality. The common aspect ratio of televisions, and computer monitors, has changed from 4,3 to 16,10, to 16,9. Early electronic computers were fitted with a panel of light bulbs where the state of each particular bulb would indicate the state of a particular register bit inside the computer. This allowed the operating the computer to monitor the internal state of the machine. As early monitors were only capable of displaying a limited amount of information. Instead, a printer was the primary output device, while the monitor was limited to keeping track of the programs operation. Multiple technologies have used for computer monitors. Until the 21st century most used cathode ray tubes but they have largely superseded by LCD monitors. The first computer monitors used cathode ray tubes, high-resolution CRT displays were developed for specialized military, industrial and scientific applications but they were far too costly for general use. Either computer could be connected to the terminals of an ordinary color TV set or used with a purpose-made CRT color monitor for optimum resolution. In 1984 IBM introduced the Enhanced Graphics Adapter which was capable of producing 16 colors and had a resolution of 640 x 350, by the end of the 1980s color CRT monitors that could clearly display 1024 x 768 pixels were widely available and increasingly affordable. During the following decade maximum display resolutions gradually increased and prices continued to fall, CRT technology remained dominant in the PC monitor market into the new millennium partly because it was cheaper to produce and offered viewing angles close to 180 degrees. CRTs still offer some image quality advantages over LCDs but improvements to the latter have made much less obvious. There are multiple technologies that have used to implement liquid crystal displays. Commonly, the laptop would be offered with an assortment of display options at increasing price points, monochrome
11.
Numerical digit
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A digit is a numeric symbol used in combinations to represent numbers in positional numeral systems. The name digit comes from the fact that the 10 digits of the hands correspond to the 10 symbols of the common base 10 numeral system, i. e. the decimal digits. In a given system, if the base is an integer. For example, the system has ten digits, whereas binary has two digits. In a basic system, a numeral is a sequence of digits. Each position in the sequence has a value, and each digit has a value. The value of the numeral is computed by multiplying each digit in the sequence by its place value, each digit in a number system represents an integer. For example, in decimal the digit 1 represents the one, and in the hexadecimal system. A positional number system must have a digit representing the integers from zero up to, but not including, thus in the positional decimal system, the numbers 0 to 9 can be expressed using their respective numerals 0 to 9 in the rightmost units position. The Hindu–Arabic numeral system uses a decimal separator, commonly a period in English, or a comma in other European languages, to denote the place or units place. Each successive place to the left of this has a value equal to the place value of the previous digit times the base. Similarly, each place to the right of the separator has a place value equal to the place value of the previous digit divided by the base. For example, in the numeral 10, the total value of the number is 1 ten,0 ones,3 tenths, and 4 hundredths. Note that the zero, which contributes no value to the number, the place value of any given digit in a numeral can be given by a simple calculation, which in itself is a compliment to the logic behind numeral systems. And to the right, the digit is multiplied by the base raised by a negative n, for example, in the number 10. This system was established by the 7th century in India, but was not yet in its modern form because the use of the digit zero had not yet widely accepted. Instead of a zero, a dot was left in the numeral as a placeholder, the first widely acknowledged use of zero was in 876. The original numerals were very similar to the ones, even down to the glyphs used to represent digits
12.
Glyph
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In typography, a glyph /ˈɡlɪf/ is an elemental symbol within an agreed set of symbols, intended to represent a readable character for the purposes of writing. In Turkish, however, it is not a glyph because that language has two versions of the letter i, with and without a dot. In Japanese syllabaries, a number of the characters are made up of more than one separate mark, however, in some cases, additional marks fulfill the role of diacritics, to differentiate distinct characters. In general, a diacritic is a glyph, even if it is contiguous with the rest of the character, two or more glyphs which have the same significance, whether used interchangeably or chosen depending on context, are called allographs of each other. The term has been used in English since 1727, borrowed from glyphe, from the Greek γλυφή, glyphē, carving, and the verb γλύφειν, glýphein, to hollow out, engrave, carve. The word glyph first came to widespread European attention with the engravings, in archaeology, a glyph is a carved or inscribed symbol. It may be a pictogram or ideogram, or part of a system such as a syllable. In 1897 Dana Evans discovered glyphs written on rocks in the Colorado Desert and these ancient characters have been called the most enlightening discovery in Native American History in the 19th Century. In typography, a glyph has a different definition, it is the specific shape, design. The same is true in computing, in computing as well as typography, the term character refers to a grapheme or grapheme-like unit of text, as found in natural language writing systems. The range of glyphs required increases correspondingly, in summary, in typography and computing, a glyph is a graphical unit. In graphonomics, the glyph is used for a noncharacter. Most typographic glyphs originate from the characters of a typeface, in the mobile text input technologies, Glyph is a family of text input methods based on the decomposition of letters into basic shapes. In role-playing games, the glyph is sometimes used alongside the word rune in describing magical drawings or etchings. Runes often refer to placing the image on an object or person to empower it, whereas the magic in a glyph lies dormant and is only triggered when the glyph is read or approached
13.
Watch
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A watch is a small timepiece intended to be carried or worn by a person. It is designed to keep working despite the motions caused by the persons activities, a wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet. A pocket watch is designed for a person to carry in a pocket, watches evolved in the 17th century from spring-powered clocks, which appeared as early as the 14th century. During most of its history the watch was a device, driven by clockwork, powered by winding a mainspring. In the 1960s the electronic quartz watch was invented, which was powered by a battery, by the 1980s the quartz watch had taken over most of the market from the mechanical watch. Today most inexpensive and medium-priced watches, used mainly for timekeeping, have quartz movements, various extra features, called complications, such as moon-phase displays and the different types of tourbillon, are sometimes included. Modern watches often display the day, date, month and year, time-related features such as timers, chronographs and alarm functions are common. Some modern designs incorporate calculators, GPS and Bluetooth technology or have heart-rate monitoring capabilities, some watches use radio clock technology to regularly correct the time. Developments in the 2010s include smartwatches, which are elaborate computer-like electronic devices designed to be worn on a wrist and they generally incorporate timekeeping functions, but these are only small fractions of what the smartwatch can do. The study of timekeeping is known as horology, watches evolved from portable spring-driven clocks, which first appeared in 15th century Europe. Watches werent widely worn in pockets until the 17th century, one account says that the word watch came from the Old English word woecce which meant watchman, because it was used by town watchmen to keep track of their shifts at work. Another says that the term came from 17th century sailors, who used the new mechanisms to time the length of their shipboard watches, the increased accuracy of the balance wheel focused attention on errors caused by other parts of the movement, igniting a two-century wave of watchmaking innovation. The first thing to be improved was the escapement, the verge escapement was replaced in quality watches by the cylinder escapement, invented by Thomas Tompion in 1695 and further developed by George Graham in the 1720s. The British had predominated in watch manufacture for much of the 17th and 18th centuries, aaron Lufkin Dennison started a factory in 1851 in Massachusetts that used interchangeable parts, and by 1861 it was running a successful enterprise incorporated as the Waltham Watch Company. The concept of the wristwatch goes back to the production of the very earliest watches in the 16th century, elizabeth I of England received a wristwatch from Robert Dudley in 1571, described as an arm watch. The oldest surviving wristwatch is one made in 1806 and given to Joséphine de Beauharnais, from the beginning, wrist watches were almost exclusively worn by women, while men used pocket-watches up until the early 20th century. The Garstin Company of London patented a Watch Wristlet design in 1893, officers in the British Army began using wristwatches during colonial military campaigns in the 1880s, such as during the Anglo-Burma War of 1885. In continental Europe Girard-Perregaux and other Swiss watch makers began supplying German naval officers with wrist watches in about 1880 and these early models were essentially standard pocket-watches fitted to a leather strap but, by the early 20th century, manufacturers began producing purpose-built wristwatches
14.
Calculator
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An electronic calculator is a small, portable electronic device used to perform operations ranging from basic arithmetic to complex mathematics. The first solid state electronic calculator was created in the 1960s, building on the history of tools such as the abacus. It was developed in parallel with the computers of the day. The pocket sized devices became available in the 1970s, especially after the first microprocessor and they later became used commonly within the petroleum industry. Modern electronic calculators vary, from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers and they became popular in the mid-1970s. By the end of decade, calculator prices had reduced to a point where a basic calculator was affordable to most. In addition to general purpose calculators, there are designed for specific markets. For example, there are scientific calculators which include trigonometric and statistical calculations, some calculators even have the ability to do computer algebra. Graphing calculators can be used to graph functions defined on the real line, as of 2016, basic calculators cost little, but the scientific and graphing models tend to cost more. In 1986, calculators still represented an estimated 41% of the worlds general-purpose hardware capacity to compute information, by 2007, this diminished to less than 0. 05%. Modern 2016 electronic calculators contain a keyboard with buttons for digits and arithmetical operations, most basic calculators assign only one digit or operation on each button, however, in more specific calculators, a button can perform multi-function working with key combinations. Large-sized figures and comma separators are used to improve readability. Various symbols for function commands may also be shown on the display, fractions such as 1⁄3 are displayed as decimal approximations, for example rounded to 0.33333333. Also, some fractions can be difficult to recognize in decimal form, as a result, Calculators also have the ability to store numbers into computer memory. Basic types of these only one number at a time. The variables can also be used for constructing formulas, some models have the ability to extend memory capacity to store more numbers, the extended memory address is termed an array index. Power sources of calculators are, batteries, solar cells or mains electricity, some models even have no turn-off button but they provide some way to put off. Crank-powered calculators were also common in the computer era
15.
Seven-segment display
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A seven-segment display, or seven-segment indicator, is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix displays. Seven-segment displays are used in digital clocks, electronic meters, basic calculators. The seven elements of the display can be lit in different combinations to represent the arabic numerals, often the seven segments are arranged in an oblique arrangement, which aids readability. The numerals 6 and 9 may be represented by two different glyphs on seven-segment displays, with or without a tail, the seven segments are arranged as a rectangle of two vertical segments on each side with one horizontal segment on the top, middle, and bottom. Additionally, the seventh segment bisects the rectangle horizontally, there are also fourteen-segment displays and sixteen-segment displays, however, these have mostly been replaced by dot matrix displays. Twenty-two segment displays capable of displaying the full ASCII character set were available in the early 1980s. The segments of a 7-segment display are referred to by the letters A to G, for gasoline price totems and other large signs, vane displays made up of electromagnetically flipped light-reflecting segments are still commonly used. An alternative to the 7-segment display in the 1950s through the 1970s was the cold-cathode, starting in 1970, RCA sold a display device known as the Numitron that used incandescent filaments arranged into a seven-segment display. Integrated displays also exist, with single or multiple digits, some of these integrated displays incorporate their own internal decoder, though most do not, each individual LED is brought out to a connecting pin as described. Multiple-digit LED displays as used in calculators and similar devices used multiplexed displays to reduce the number of I/O pins required to control the display. For example, all the anodes of the A segments of each digit position would be connected together and to a driver circuit pin, while the cathodes of all segments for each digit would be connected. In this manner an eight digit display with seven segments and a point would require only 8 cathode drivers and 8 anode drivers, instead of sixty-four drivers. A single byte can encode the full state of a 7-segment-display, the most popular bit encodings are gfedcba and abcdefg, where each letter represents a particular segment in the display. In the gfedcba representation, a value of 0x06 would turn on segments c and b. In 1908, F. W. Wood invented an 8-segment display, in 1910, a seven-segment display illuminated by incandescent bulbs was used on a power-plant boiler room signal panel. They were also used to show the dialed telephone number to operators during the transition from manual to automatic telephone dialing and they did not achieve widespread use until the advent of LEDs in the 1970s. For many applications, dot-matrix LCDs have largely superseded LED displays, unlike LEDs, the shapes of elements in an LCD panel are arbitrary since they are formed on the display by a kind of printing process. The seven-segment display has inspired designers to produce typefaces reminiscent of that display, such as New Alphabet, DB LCD Temp, ION B
16.
Nine-segment display
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A nine-segment display is a type of display based on 9 segments that can be turned on or off according to the graphic pattern to be produced. It is an extension of the more common seven-segment display, having an additional two diagonal or vertical segments between the top, middle, and bottom horizontal segments and this provides a minimal method of displaying alphanumeric characters. The extra two bars were slanted forward, allowing for an appropriate-looking И, and to differentiate the numeral 3 from the letter З, the Sharp Compet calculator also uses a 9-segment display, allowing a small range of characters and symbols to be used. Nine-segment displays are used in many Timex digital watches, and some pagers, such as the Nixxo XPage, the Arch BR502 pager, and they are also used in some Epson Stylus printers, and Newport iSeries digital meters. The display used in the iSeries is unique in that it has an extra segment at top. This allows for a somewhat more natural-appearing R and M and N, the letters displayed by a nine-segment display are not necessarily consistently uppercase or lowercase in shape. A common compromise is to use a lower-case n instead of N, depending on the design of the display segments, the use of the extra two segments may be avoided whenever possible, as in the Nixxo XPages tall-lowercase r and y. Perhaps to avoid this awkward inconsistency, the Scope Geo N8T does not allow the use of uppercase or lowercase versions of the letters J, K, Q, W, X, Y, a nine-segment display has been developed for displaying Bengali and Roman numerals. Fourteen-segment display Sixteen-segment display Dot matrix display Media related to Nine-segment display at Wikimedia Commons
17.
Fourteen-segment display
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A fourteen-segment display is a type of display based on 14 segments that can be turned on or off to produce letters and numerals. It is an expansion of the more common seven-segment display, having an additional four diagonal, a seven-segment display suffices for numerals and certain letters, but unambiguously rendering the ISO basic Latin alphabet requires more detail. A slight variation is the sixteen-segment display which allows additional legibility in displaying letters or other symbols, electronic alphanumeric displays may use LEDs, LCDs, or vacuum fluorescent display devices. The LED variant is manufactured in single or dual character packages. Often a character generator is used to translate 7-bit ASCII character codes to the 14 bits that indicate which of the 14 segments to turn on or off. Multiple-segment display devices use fewer elements than a full dot-matrix display and this can reduce the number of driver components and power consumption. Fourteen-segment gas-plasma displays were used in pinball machines from 1986 through 1991 with an additional comma, Fourteen and sixteen-segment displays were used to produce alphanumeric characters on calculators and other embedded systems. Applications today include displays fitted to telephone Caller ID units, gymnasium equipment, VCRs, car stereos, microwave ovens, slot machines, such displays were very common on pinball machines for displaying the score and other information, before the widespread use of dot-matrix display panels. Multiple segment alphanumeric displays are nearly as old as the use of electricity, a 1908 textbook describes an alphanumeric display system using incandescent lamps and a mechanical switching arrangement. Each of 21 lamps was connected to a switch operated by a set of slotted bars and this commutator assembly could be arranged so that as the drum was rotated, different sets of switches were closed and different letters and figures could be displayed. A few different versions of the fourteen segment display exist as cold-cathode neon lamps, for example, one type made by Burroughs Corporation was called Panaplex. Instead of using a filament as the incandescent versions do, these use a cathode charged to a 180 V potential which causes the segment to glow a bright orange color. They operated similarly to Nixie tubes but instead of the full-formed numeric shapes, used segments to make up numerals, seven-segment display Nine-segment display Sixteen segment display Dot matrix display Media related to Fourteen segment displays at Wikimedia Commons
18.
Sixteen-segment display
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A sixteen-segment display is a type of display based on 16 segments that can be turned on or off according to the graphic pattern to be produced. It is an extension of the more common seven-segment display, adding four diagonal, other variants include the fourteen-segment display which does not split the top or bottom horizontal segments, and the twenty two-segment display that allows lower-case characters with descenders. Often a character generator is used to translate 7-bit ASCII character codes to the 16 bits that indicate which of the 16 segments to turn on or off, sixteen-segment displays were originally designed to display alphanumeric characters. Later they were used to display Thai numerals and Persian characters, non-electronic displays using this pattern existed as early as 1902. However, they are sometimes used on VCRs, car stereos, microwave ovens, telephone Caller ID displays. Sixteen-segment displays may be based on one of several technologies, the three most common types being LED, LCD and VFD. The LED variant is manufactured in single or dual character packages. Such displays were common on pinball machines for displaying the score and other information
19.
Hitachi HD44780 LCD controller
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The Hitachi HD44780 LCD controller is an alphanumeric dot matrix liquid crystal display controller developed by Hitachi that was commonly used during the MCS-51 era. It was made available around year 1987. The character set of the controller includes ASCII characters, Japanese Kana characters, using an extension driver, the device can display up to 80 characters. Compatible LCD screens are manufactured in several standard configurations, common sizes are one row of eight characters, and 16×2, 20×2 and 20×4 formats. Larger custom sizes are made with 32,40 and 80 characters, the most commonly manufactured larger configuration is 40x4. Characters, which requires two individually addressable HD44780 controllers with expansion chips as a single HD44780 chip can only address up to 80 characters, a common smaller size is 16×2, and this size is readily available as surplus stock for hobbyist and prototyping work. Character LCDs may have a backlight, which may be LED, fluorescent, character LCDs use a 16 contact interface, commonly using pins or card edge connections on 0.1 inch centers. Those without backlights may have only 14 pins, omitting the two pins powering the light, the pinout is as follows, Ground VCC Contrast adjustment Register Select. Non-LED backlights often require higher voltages, selecting 4-bit or 8-bit mode requires careful selection of commands. First, with D3-D0 unconnected, these lines will appear low to the HD44780 when it is in 8-bit mode. The following algorithm ensures that the LCD is in the mode, Set D7-D4 to 0b0011. If in State1, the LCD will see the command as 0b0011_0000, if in State2, the LCD will simply latch the value 0b0011 into bits 7-4 and then move to State3. If in State3, the LCD will latch the value 0b0011 into bits 3-0, repeat the above, setting D7-D4 to 0b0011 and toggling the enable bit again. If in State1, the LCD will remain in 8-bit mode just as above, if in State2, it will latch the value into bits 7-4 and move to State3, just as above. If in State3, the LCD will latch the value into bits 3-0 just as above, however, the command will no longer be random, but will be the 0b0011 that was latched from State2 in the previous iteration. Thus, the LCD will switch to 8-bit mode and change to State1, the LCD is now in either State1 or State 3. Repeat the previous step one more time, if in State1, the LCD will remain in 8-bit mode. The LCD can no longer be in State2 at this point, now that the LCD is definitely in 8-bit mode, it can be switched to 4-bit mode if desired
20.
Incandescent light bulb
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An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light. The filament, heated by passing a current through it, is protected from oxidation with a glass or quartz bulb that is filled with inert gas or evacuated. In a halogen lamp, filament evaporation is prevented by a process that redeposits metal vapor onto the filament. The light bulb is supplied with current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides mechanical support, 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 regulating equipment, have low manufacturing costs, the remaining energy is converted into heat. The luminous efficacy of an incandescent bulb is 16 lumens per watt. Some applications of the incandescent bulb deliberately use the heat generated by the filament, such applications include incubators, brooding boxes for poultry, heat lights for reptile tanks, infrared heating for industrial heating and drying processes, lava lamps, and the Easy-Bake Oven toy. In addressing the question of who invented the incandescent lamp, historians Robert Friedel and Paul Israel list 22 inventors of incandescent lamps prior to Joseph Swan, historian Thomas Hughes has attributed Edisons success to his development of an entire, integrated system of electric lighting. In 1761 Ebenezer Kinnersley demonstrated heating a wire to incandescence and it was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years. Over the first three-quarters of the 19th century many experimenters worked with various combinations of platinum or iridium wires, carbon rods, many of these devices were demonstrated and some were patented. In 1835, James Bowman Lindsay demonstrated a constant electric light at a meeting in Dundee. He stated that he could read a book at a distance of one, however, having perfected the device to his own satisfaction, he turned to the problem of wireless telegraphy and did not develop the electric light any further. His claims are not well documented, although he is credited in Challoner et al. with being the inventor of the Incandescent Light Bulb, in 1838, Belgian lithographer Marcellin Jobard invented an incandescent light bulb with a vacuum atmosphere using a carbon filament. In 1840, British scientist Warren de la Rue enclosed a coiled platinum filament in a vacuum tube, although a workable design, the cost of the platinum made it impractical for commercial use. In 1841, Frederick de Moleyns of England was granted the first patent for an incandescent lamp, in 1845, American John W. Starr acquired a patent for his incandescent light bulb involving the use of carbon filaments. He died shortly after obtaining the patent, and his invention was never produced commercially, little else is known about him. In 1851, Jean Eugène Robert-Houdin publicly demonstrated incandescent light bulbs on his estate in Blois and his light bulbs are on display in the museum of the Château de Blois
21.
Cold cathode
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A cold cathode is a cathode that is not electrically heated by a filament. A cathode may be considered if it emits more electrons than can be supplied by thermionic emission alone. It is used in lamps, such as neon lamps, discharge tubes. The other type of cathode is a hot cathode, which is heated by current passing through a filament. A cold cathode does not necessarily operate at a low temperature, it is heated to its operating temperature by other methods. A cold-cathode vacuum tube does not rely on external heating of an electrode to provide thermionic emission of electrons, early cold-cathode devices included the Geissler tube and Plucker tube, and early cathode ray tubes. Study of the phenomena in these devices led to the discovery of the electron, neon lamps are used both to produce light as indicators and for special-purpose illumination, and also as circuit elements displaying negative resistance. Addition of an electrode to a device allowed the glow discharge to be initiated by an external control circuit. Many types of cold-cathode switching tube were developed, including types of thyratron. Voltage regulator tubes rely on the constant voltage of a glow discharge over a range of current. A Dekatron is a tube with multiple electrodes that is used for counting. Counter tubes were used widely before development of integrated circuit counter devices, the flash tube is a cold-cathode device filled with xenon gas, used to produce an intense short pulse of light for photography or to act as a stroboscope to examine the motion of moving parts. Cold-cathode lamps include cold-cathode fluorescent lamps and neon lamps, cold-cathode fluorescent lamps are used for backlighting of LCDs, for example computer monitors and television screens. In the lighting industry, “cold cathode” historically refers to luminous tubing which is larger than 20mm in diameter and this larger diameter tubing is often used for interior alcove and general lighting. The term neon lamp refers to tubing that is smaller than 15 mm diameter and these lamps are commonly used for neon signs. The cathode is the negative electrode, any gas discharge lamp has a positive and a negative electrode. Both electrodes alternate between acting as an anode and a cathode when these devices run with alternating current, a cold cathode is distinguished from a hot cathode that is heated to induce thermionic emission of electrons. Discharge tubes with hot cathodes have an envelope filled with low pressure gas, examples are most common fluorescent lamps, high pressure discharge lamps and vacuum fluorescent displays
22.
Light-emitting diode
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A light-emitting diode is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated, when a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light is determined by the band gap of the semiconductor. LEDs are typically small and integrated optical components may be used to shape the radiation pattern, appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are still used as transmitting elements in remote-control circuits. The first visible-light LEDs were also of low intensity and limited to red, modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness. Early LEDs were often used as indicator lamps for electronic devices and they were soon packaged into numeric readouts in the form of seven-segment displays and were commonly seen in digital clocks. Recent developments in LEDs permit them to be used in environmental, LEDs have allowed new displays and sensors to be developed, while their high switching rates are also used in advanced communications technology. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Light-emitting diodes are now used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, as of 2017, LED lights home room lighting are as cheap or cheaper than compact fluorescent lamp sources of comparable output. They are also more energy efficient and, arguably, have fewer environmental concerns linked to their disposal. Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide, russian inventor Oleg Losev reported creation of the first LED in 1927. His research was distributed in Soviet, German and British scientific journals, rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide and other semiconductor alloys in 1955. Braunstein observed infrared emission generated by simple diode structures using gallium antimonide, GaAs, indium phosphide, in 1957, Braunstein further demonstrated that the rudimentary devices could be used for non-radio communication across a short distance. As noted by Kroemer Braunstein …had set up a simple optical communications link, the emitted light was detected by a PbS diode some distance away. This signal was fed into an amplifier and played back by a loudspeaker. Intercepting the beam stopped the music and we had a great deal of fun playing with this setup. This setup presaged the use of LEDs for optical communication applications, by October 1961, they had demonstrated efficient light emission and signal coupling between a GaAs p-n junction light emitter and an electrically-isolated semiconductor photodetector
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Liquid-crystal display
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A liquid-crystal display is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals. Liquid crystals do not emit light directly, instead using a backlight or reflector to produce images in color or monochrome and they use the same basic technology, except that arbitrary images are made up of a large number of small pixels, while other displays have larger elements. LCDs are used in a range of applications including computer monitors, televisions, instrument panels, aircraft cockpit displays. Small LCD screens are common in consumer devices such as digital cameras, watches, calculators. LCD screens are used on consumer electronics products such as DVD players, video game devices. LCD screens have replaced heavy, bulky cathode ray tube displays in all applications. LCD screens are available in a range of screen sizes than CRT and plasma displays, with LCD screens available in sizes ranging from tiny digital watches to huge. Since LCD screens do not use phosphors, they do not suffer image burn-in when an image is displayed on a screen for a long time. LCDs are, however, susceptible to image persistence, the LCD screen is more energy-efficient and can be disposed of more safely than a CRT can. Its low electrical power consumption enables it to be used in battery-powered electronic equipment more efficiently than CRTs can be, by 2008, annual sales of televisions with LCD screens exceeded sales of CRT units worldwide, and the CRT became obsolete for most purposes. Without the liquid crystal between the filters, light passing through the first filter would be blocked by the second polarizer. Before an electric field is applied, the orientation of the molecules is determined by the alignment at the surfaces of electrodes. In a twisted nematic device, the surface alignment directions at the two electrodes are perpendicular to other, and so the molecules arrange themselves in a helical structure. This induces the rotation of the polarization of the incident light, and this light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the voltage applied across the liquid crystal layer in each pixel, color LCD systems use the same technique, with color filters used to generate red, green, and blue pixels. The optical effect of a TN device in the state is far less dependent on variations in the device thickness than that in the voltage-off state. Because of this, TN displays with low content and no backlighting are usually operated between crossed polarizers such that they appear bright with no voltage. When no image is displayed, different arrangements are used, for this purpose, TN LCDs are operated between parallel polarizers, whereas IPS LCDs feature crossed polarizers
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Two-dimensional space
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In physics and mathematics, two-dimensional space is a geometric model of the planar projection of the physical universe. The two dimensions are commonly called length and width, both directions lie in the same plane. A sequence of n numbers can be understood as a location in n-dimensional space. When n =2, the set of all locations is called two-dimensional space or bi-dimensional space. Each reference line is called an axis or just axis of the system. The coordinates can also be defined as the positions of the projections of the point onto the two axes, expressed as signed distances from the origin. The idea of system was developed in 1637 in writings by Descartes and independently by Pierre de Fermat. Both authors used a single axis in their treatments and have a length measured in reference to this axis. The concept of using a pair of axes was introduced later, after Descartes La Géométrie was translated into Latin in 1649 by Frans van Schooten and these commentators introduced several concepts while trying to clarify the ideas contained in Descartes work. Later, the plane was thought of as a field, where any two points could be multiplied and, except for 0, divided and this was known as the complex plane. The complex plane is called the Argand plane because it is used in Argand diagrams. These are named after Jean-Robert Argand, although they were first described by Norwegian-Danish land surveyor, Argand diagrams are frequently used to plot the positions of the poles and zeroes of a function in the complex plane. In mathematics, analytic geometry describes every point in space by means of two coordinates. Two perpendicular coordinate axes are given which cross each other at the origin and they are usually labeled x and y. Another widely used system is the polar coordinate system, which specifies a point in terms of its distance from the origin. In two dimensions, there are infinitely many polytopes, the polygons, the first few regular ones are shown below, The Schläfli symbol represents a regular p-gon. The regular henagon and regular digon can be considered degenerate regular polygons and they can exist nondegenerately in non-Euclidean spaces like on a 2-sphere or a 2-torus. There exist infinitely many non-convex regular polytopes in two dimensions, whose Schläfli symbols consist of rational numbers and they are called star polygons and share the same vertex arrangements of the convex regular polygons
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Rectangle
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In Euclidean plane geometry, a rectangle is a quadrilateral with four right angles. It can also be defined as a quadrilateral, since equiangular means that all of its angles are equal. It can also be defined as a parallelogram containing a right angle, a rectangle with four sides of equal length is a square. The term oblong is occasionally used to refer to a non-square rectangle, a rectangle with vertices ABCD would be denoted as ABCD. The word rectangle comes from the Latin rectangulus, which is a combination of rectus and angulus, a crossed rectangle is a crossed quadrilateral which consists of two opposite sides of a rectangle along with the two diagonals. It is a case of an antiparallelogram, and its angles are not right angles. Other geometries, such as spherical, elliptic, and hyperbolic, have so-called rectangles with sides equal in length. Rectangles are involved in many tiling problems, such as tiling the plane by rectangles or tiling a rectangle by polygons, a convex quadrilateral with successive sides a, b, c, d whose area is 12. A rectangle is a case of a parallelogram in which each pair of adjacent sides is perpendicular. A parallelogram is a case of a trapezium in which both pairs of opposite sides are parallel and equal in length. A trapezium is a quadrilateral which has at least one pair of parallel opposite sides. A convex quadrilateral is Simple, The boundary does not cross itself, star-shaped, The whole interior is visible from a single point, without crossing any edge. De Villiers defines a more generally as any quadrilateral with axes of symmetry through each pair of opposite sides. This definition includes both right-angled rectangles and crossed rectangles, quadrilaterals with two axes of symmetry, each through a pair of opposite sides, belong to the larger class of quadrilaterals with at least one axis of symmetry through a pair of opposite sides. These quadrilaterals comprise isosceles trapezia and crossed isosceles trapezia, a rectangle is cyclic, all corners lie on a single circle. It is equiangular, all its corner angles are equal and it is isogonal or vertex-transitive, all corners lie within the same symmetry orbit. It has two lines of symmetry and rotational symmetry of order 2. The dual polygon of a rectangle is a rhombus, as shown in the table below, the figure formed by joining, in order, the midpoints of the sides of a rectangle is a rhombus and vice versa
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Video
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Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video systems vary greatly in the resolution of the display and refresh rate, video can be carried on a variety of media, including radio broadcast, tapes, DVDs, computer files etc. Video was originally exclusively a live technology, charles Ginsburg led an Ampex research team developing one of the first practical video tape recorder. In 1951 the first video tape recorder captured live images from television cameras by converting the electrical impulses. Video recorders were sold for $50,000 in 1956, however, prices gradually dropped over the years, in 1971, Sony began selling videocassette recorder decks and tapes into the consumer market. The use of techniques in video created digital video, which allowed higher quality and, eventually. After the invention of the DVD in 1997 and Blu-ray Disc in 2006, sales of videotape, the advent of digital broadcasting and the subsequent digital television transition is in the process of relegating analog video to the status of a legacy technology in most parts of the world. PAL standards and SECAM specify 25 frame/s, while NTSC standards specify 29.97 frames, film is shot at the slower frame rate of 24 frames per second, which slightly complicates the process of transferring a cinematic motion picture to video. The minimum frame rate to achieve a comfortable illusion of an image is about sixteen frames per second. Video can be interlaced or progressive, analog display devices reproduce each frame in the same way, effectively doubling the frame rate as far as perceptible overall flicker is concerned. NTSC, PAL and SECAM are interlaced formats, abbreviated video resolution specifications often include an i to indicate interlacing. For example, PAL video format is specified as 576i50, where 576 indicates the total number of horizontal scan lines, i indicates interlacing. In progressive scan systems, each refresh period updates all scan lines in each frame in sequence, when displaying a natively progressive broadcast or recorded signal, the result is optimum spatial resolution of both the stationary and moving parts of the image. Deinterlacing cannot, however, produce video quality that is equivalent to true progressive scan source material, aspect ratio describes the dimensions of video screens and video picture elements. All popular video formats are rectilinear, and so can be described by a ratio between width and height, the screen aspect ratio of a traditional television screen is 4,3, or about 1.33,1. High definition televisions use a ratio of 16,9. The aspect ratio of a full 35 mm film frame with soundtrack is 1.375,1. Therefore, a 720 by 480 pixel NTSC DV image displayes with the 4,3 aspect ratio if the pixels are thin, the popularity of viewing video on mobile phones has led to the growth of vertical video
27.
Television set
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A television set, more commonly called a television, TV, TV set, television receiver, or telly, is a device that combines a tuner, display, and loudspeakers for the purpose of viewing television. Introduced in the late 1920s in mechanical form, television became a popular consumer product after World War II in electronic form. The addition of color to broadcast television after 1953 further increased the popularity of television sets in the 1960s, the ubiquitous television set became the display device for the first recorded media in the 1970s, such as Betamax, VHS and later DVD. It was also the display device for the first generation of home computers, in the 2010s flat panel television incorporating liquid-crystal displays, especially LED-backlit LCDs, largely replaced cathode ray tubes and other displays. Modern flat panel TVs are typically capable of display and can also play content from a USB device. Mechanical televisions were sold from 1928 to 1934 in the United Kingdom, United States. The Baird Televisor is considered the first mass-produced television, selling about a thousand units, the first commercially made electronic televisions with cathode ray tubes were manufactured by Telefunken in Germany in 1934, followed by other makers in France, Britain, and America. The cheapest model with a 12-inch screen was $445, an estimated 19,000 electronic televisions were manufactured in Britain, and about 1,600 in Germany, before World War II. About 7, 000–8,000 electronic sets were made in the U. S. before the War Production Board halted manufacture in April 1942, production resuming in August 1945. While only 0. 5% of U. S. households had a television in 1946,55. 7% had one in 1954, and 90% by 1962. In Britain, there were 15,000 television households in 1947,1.4 million in 1952, by the late 1960s and early 1970s, color television had come into wide use. In Britain, BBC1, BBC2 and ITV were regularly broadcasting in colour by 1969, during the first decade of the 21st century, CRT picture tube display technology was almost entirely supplanted worldwide by flat panel displays. By the early 2010s, LCD TVs, which increasingly used LED-backlit LCDs, television sets may employ one of several available display technologies. The production of plasma and CRT displays has been almost completely discontinued, the cathode ray tube is a vacuum tube containing one or more electron guns and a fluorescent screen used to view images. It has a means to accelerate and deflect the beam onto the screen to create the images. The images may represent electrical waveforms, pictures, radar targets or others, the CRT uses an evacuated glass envelope which is large, deep, fairly heavy, and relatively fragile. As a matter of safety, the face is made of thick lead glass so as to be highly shatter-resistant and to block most X-ray emissions. In television sets and computer monitors, the front area of the tube is scanned repetitively and systematically in a fixed pattern called a raster
28.
Head-mounted display
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A head-mounted display, both abbreviated HMD, is a display device, worn on the head or as part of a helmet, that has a small display optic in front of one or each eye. A HMD has many uses including in gaming, aviation, engineering, there is also an optical head-mounted display, which is a wearable display that can reflect projected images and allows a user to see through it. A typical HMD has one or two small displays, with lenses and semi-transparent mirrors embedded in eyeglasses, a visor, or a helmet, the display units are miniaturised and may include cathode ray tubes, liquid crystal displays, liquid crystal on silicon, or organic light-emitting diodes. Some vendors employ multiple micro-displays to increase resolution and field of view. HMDs differ in whether they can display only computer-generated imagery, or only live imagery from the physical world, most HMDs can display only a computer-generated image, sometimes referred to as a virtual image. Some HMDs can allow a CGI to be superimposed on a real-world view and this is sometimes referred to as augmented reality or mixed reality. Combining real-world view with CGI can be done by projecting the CGI through a partially reflective mirror and this method is often called optical see-through. Combining real-world view with CGI can also be done electronically by accepting video from a camera and this method is often called video see-through. An optical head-mounted display uses an optical mixer which is made of partly silvered mirrors and it can reflect artificial images, and let real images cross the lens, and let a user look through it. Various methods have existed for see-through HMDs, most of which can be summarized into two families based on curved mirrors or waveguides. Curved mirrors have been used by Laster Technologies, and by Vuzix in their Star 1200 product, various waveguide methods have existed for years. These include diffraction optics, holographic optics, polarized optics, major HMD applications include military, government, and civilian-commercial. In 1962, Hughes Aircraft Company revealed the Electrocular, a compact CRT, ruggedized HMDs are increasingly being integrated into the cockpits of modern helicopters and fighter aircraft. These are usually integrated with the pilots flying helmet and may include protective visors, night vision devices. Military, police, and firefighters use HMDs to display information such as maps or thermal imaging data while viewing a real scene. Recent applications have included the use of HMD for paratroopers, in 2005, the Liteye HMD was introduced for ground combat troops as a rugged, waterproof lightweight display that clips into a standard US PVS-14 military helmet mount. The self-contained color monocular organic light-emitting diode display replaces the NVG tube, the LE has see-through ability and can be used as a standard HMD or for augmented reality applications. The design is optimized to provide high definition data under all lighting conditions, the LE has a low power consumption, operating on four AA batteries for 35 hours or receiving power via standard Universal Serial Bus connection
29.
Broadcast reference monitor
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It may or may not have professional audio monitoring capability. Unlike a television set, a video monitor has no tuner and, video monitors are used extensively in the security industry with closed-circuit television cameras and recording devices. Broadcast monitors will try to avoid post processing such as a scaler, line doubling. However, display technologies with fixed pixel structures must perform image scaling when displaying SD signals as the signal contains non-square pixels while the display has square pixels, lCDs and plasmas are also inherently progressive displays and may need to perform deinterlacing on interlaced video signals. GPI interface - For receiving external triggers, modular expansion card slots that support SD-SDI or HD-SDI single link or dual-link HD-SDI cards
30.
Monitoring (medicine)
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In medicine, monitoring is the observation of a disease, condition or one or several medical parameters over time. It can be performed by continuously measuring certain parameters by using a monitor, and/or by repeatedly performing medical tests. Transmitting data from a monitor to a distant monitoring station is known as telemetry or biotelemetry, a small monitor worn by an ambulatory patient for this purpose is known as a Holter monitor. Cardiac monitoring can also involve cardiac output monitoring via an invasive Swan-Ganz catheter, hemodynamic monitoring, which monitors the blood pressure and blood flow within the circulatory system. Blood pressure can be measured either invasively through a blood pressure transducer assembly. Also, there are special patient monitors which incorporate the monitoring of brain waves, gas concentrations, bispectral index. They are usually incorporated into anesthesia machines, in neurosurgery intensive care units, brain EEG monitors have a larger multichannel capability and can monitor other physiological events, as well. Blood glucose monitoring Childbirth monitoring Body temperature monitoring through an adhesive pad containing a thermoelectric transducer and these allow for continuous monitoring of a patient, with medical staff being continuously informed of the changes in general condition of a patient. Some monitors can even warn of pending fatal cardiac conditions before visible signs are noticeable to clinical staff, a medical monitor or physiological monitor is a medical device used for monitoring. It can consist of one or more sensors, processing components, display devices, sensors of medical monitors include biosensors and mechanical sensors. Besides the tracings of physiological parameters along time, digital medical displays have automated numeric readouts of the peak and/or average parameters displayed on the screen, old analog patient displays, in contrast, were based on oscilloscopes, and had one channel only, usually reserved for electrocardiographic monitoring. Therefore, medical monitors tended to be highly specialized, one monitor would track a patients blood pressure, while another would measure pulse oximetry, another the ECG. Later analog models had a second or third channel displayed in the screen, usually to monitor respiration movements. Ambulatory telemetry can also be achieved by portable, battery-operated models which are carried by the patient and this newer method of charting patient data reduces the likelihood of human documentation error and will eventually reduce overall paper consumption. In addition, automated ECG interpretation incorporates diagnostic codes automatically into the charts, long-distance connectivity can avail for telemedicine, which involves provision of clinical health care at a distance. A medical monitor can also have the function to produce an alarm to alert the staff when certain criteria are set, an entirely new scope is opened with mobile carried monitors, even such in sub-skin carriage. This class of monitors delivers information gathered in body-area networking to e. g. smart phones, monitoring of clinical parameters is primarily intended to detect changes in the clinical status of an individual. For example, the parameter of oxygen saturation is usually monitored to detect changes in respiratory capability of an individual, when monitoring a clinical parameters, differences between test results can reflect either an actual change in the status of the condition or a test-retest variability of the test method
31.
Cathode ray tube
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The cathode ray tube is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images. It modulates, accelerates, and deflects electron beam onto the screen to create the images, the images may represent electrical waveforms, pictures, radar targets, or others. CRTs have also used as memory devices, in which case the visible light emitted from the fluorescent material is not intended to have significant meaning to a visual observer. In television sets and computer monitors, the front area of the tube is scanned repetitively and systematically in a fixed pattern called a raster. An image is produced by controlling the intensity of each of the three beams, one for each additive primary color with a video signal as a reference. A CRT is constructed from an envelope which is large, deep, fairly heavy. The interior of a CRT is evacuated to approximately 0.01 Pa to 133 nPa. evacuation being necessary to facilitate the flight of electrons from the gun to the tubes face. That it is evacuated makes handling an intact CRT potentially dangerous due to the risk of breaking the tube and causing a violent implosion that can hurl shards of glass at great velocity. As a matter of safety, the face is made of thick lead glass so as to be highly shatter-resistant and to block most X-ray emissions. Flat panel displays can also be made in large sizes, whereas 38 to 40 was about the largest size of a CRT television, flat panels are available in 60. Cathode rays were discovered by Johann Hittorf in 1869 in primitive Crookes tubes and he observed that some unknown rays were emitted from the cathode which could cast shadows on the glowing wall of the tube, indicating the rays were traveling in straight lines. In 1890, Arthur Schuster demonstrated cathode rays could be deflected by electric fields, the earliest version of the CRT was known as the Braun tube, invented by the German physicist Ferdinand Braun in 1897. It was a diode, a modification of the Crookes tube with a phosphor-coated screen. In 1907, Russian scientist Boris Rosing used a CRT in the end of an experimental video signal to form a picture. He managed to display simple geometric shapes onto the screen, which marked the first time that CRT technology was used for what is now known as television. The first cathode ray tube to use a hot cathode was developed by John B. Johnson and Harry Weiner Weinhart of Western Electric and it was named by inventor Vladimir K. Zworykin in 1929. RCA was granted a trademark for the term in 1932, it released the term to the public domain in 1950. The first commercially made electronic television sets with cathode ray tubes were manufactured by Telefunken in Germany in 1934, in oscilloscope CRTs, electrostatic deflection is used, rather than the magnetic deflection commonly used with television and other large CRTs
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LED display
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An LED display is a flat panel display, which uses an array of light-emitting diodes as pixels for a video display. Their brightness allows them to be used outdoors in store signs and billboards, LED displays are capable of providing general illumination in addition to visual display, as when used for stage lighting or other decorative purposes. The first true all-LED flat panel television screen was developed, demonstrated and documented by James P. Mitchell in 1977. Initial public recognition came from the Westinghouse Educational Foundation Science Talent Search group, the paper entry was named in the Honors Group publicized to universities on January 25,1978. The paper was subsequently invited and presented at the Iowa Academy of Science at the University of Northern Iowa, the operational prototype was displayed at the Eastern Iowa SEF on March 18 and obtained a top Physical Sciences award and IEEE recognition. The project was displayed at the 29th International SEF at the Anaheim Ca. The ¼-inch thin miniature flat panel modular prototype, scientific paper and it received awards by NASA and General Motors Corporation. Mitchells paper projected the future replacement of CRTs and included foreseen application to battery operated devices due the advantages of low-power, displacement of the electromagnetic scan systems included the removal of inductive deflection, electron beam and color convergence circuits and has been a significant achievement. The 1977 model was monochromatic by design, the efficient Blue LED completing the color triad, did not arrive for another decade. Large displays now use high-brightness diodes to generate a wide spectrum of colors and it took three decades and organic light-emitting diodes for Sony to introduce an OLED TV, the Sony XEL-1 OLED screen which was marketed in 2009. Later, at CES2012, Sony presented Crystal LED, a TV with a true LED-display, the 2011 UEFA Champions League Final match between Manchester United and Barcelona was broadcast live in 3D format in Gothenburg, on an EKTA screen. It had a rate of 100 Hz, a diagonal of 7.11 m and a display area of 6. 192×3.483 m. AMOLED Media related to LED displays at Wikimedia Commons
33.
Electronic paper
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Electronic paper and e-paper are display devices that mimic the appearance of ordinary ink on paper. Unlike conventional backlit flat panel displays that light, electronic paper displays reflect light like paper. This may make them comfortable to read, and provide a wider viewing angle than most light-emitting displays. The contrast ratio in electronic displays available as of 2008 approaches newspaper, an ideal e-paper display can be read in direct sunlight without the image appearing to fade. Many electronic paper technologies hold static text and images indefinitely without electricity, flexible electronic paper uses plastic substrates and plastic electronics for the display backplane. There is ongoing competition among manufacturers to provide full-color ability, Electronic paper was first developed in the 1970s by Nick Sheridon at Xeroxs Palo Alto Research Center. The first electronic paper, called Gyricon, consisted of polyethylene spheres between 75 and 106 micrometers across, each sphere is a janus particle composed of negatively charged black plastic on one side and positively charged white plastic on the other. The spheres are embedded in a transparent silicone sheet, with each sphere suspended in a bubble of oil so that they can rotate freely. The polarity of the applied to each pair of electrodes then determines whether the white or black side is face-up. At the FPD2008 exhibition, Japanese company Soken demonstrated a wall with electronic wall-paper using this technology, in the simplest implementation of an electrophoretic display, titanium dioxide particles approximately one micrometer in diameter are dispersed in a hydrocarbon oil. A dark-colored dye is added to the oil, along with surfactants. This mixture is placed between two parallel, conductive plates separated by a gap of 10 to 100 micrometres, when a voltage is applied across the two plates, the particles migrate electrophoretically to the plate that bears the opposite charge from that on the particles. When the particles are located at the front side of the display, it appears white, when the particles are located at the rear side of the display, it appears dark, because the incident light is absorbed by the colored dye. Electrophoretic displays are considered examples of the electronic paper category, because of their paper-like appearance. These displays are constructed from an electrophoretic imaging film manufactured by E Ink Corporation, a mobile phone that used the technology is the Motorola Fone. Electrophoretic Display technology has also developed by Sipix and Bridgestone/Delta. SiPix is now part of E Ink, the Sipix design uses a flexible 0. 15mm Microcup architecture, instead of E Inks 0. 04mm diameter microcapsules. Bridgestone Corp. s Advanced Materials Division cooperated with Delta Optoelectronics Inc. in developing the Quick Response Liquid Powder Display technology, an electrophoretic display forms images by rearranging charged pigment particles with an applied electric field
34.
E Ink
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E Ink is a paper-like display technology, characterized by high brightness and contrast, a wide viewing angle, and ultra-low power requirements. The notion of a low-power paper-like display had existed since the 1970s, originally conceived by researchers at Xerox PARC, neil Gershenfeld brought in Jacobson to the MIT Media Lab in 1995 after hearing his ideas for an electronic book. Jacobson, in turn, recruited MIT undergrads Barrett Comiskey, a major, and J. D. Albert. Comiskey experimented with charging and encapsulating those all-white particles in microcapsules mixed in with a dark dye, the result was a system of microcapsules which could be applied to a surface and then could be charged independently to create black and white images. A first patent was filed for this microencapsulated electrophoretic display by MIT in October 1996, the scientific paper was featured on the cover of peer-reviewed journal Nature, unusual for work done by undergraduate students. In this context, microparticle-based displays have long intrigued researchers, micro-particle-based displays possess intrinsic bistability, exhibit extremely low power d. c. field addressing and have demonstrated high contrast and reflectivity. These features, combined with a near-lambertian viewing characteristic, result in an ‘ink on paper’ look, but such displays have to date suffered from short lifetimes and difficulty in manufacture. Here we report the synthesis of an electrophoretic ink based on the microencapsulation of an electrophoretic dispersion, the use of a microencapsulated electrophoretic medium solves the lifetime issues and permits the fabrication of a bistable electronic display solely by means of printing. This system may satisfy the requirements of electronic paper. ”A second patent was filed on the microencapsulated electrophoretic display by MIT in March 1997. On June 1,2009, E Ink Corp. announced an agreement to be purchased by one of its business partners. However, from June to December 2009, the price was re-negotiated. The purchase by this Taiwanese company has put the production of the E Ink EPD on a scale than before. Ltd and maintains a strategic relationship with Chi Mei Optoelectronics Corp. which is now Chimei InnoLux Corporation. In December 2012, E Ink acquired SiPix, a rival electrophoretic display company, the NIHF is an elite collection of engineers and innovators, only 100 of whom are living, with 532 total from the past 300 years. E Ink is processed into a film for integration into electronic displays and has enabled novel applications in phones, watches, magazines, wearables and e-readers, etc. The Motorola F3 was the first mobile phone to employ E Ink technology into its display, in addition, the Samsung Alias 2 uses this technology on the keypad, to allow orientation to change. The October 2008 limited edition North American issue of Esquire was the first magazine cover to integrate E Ink, the cover was manufactured in Shanghai, China, was shipped refrigerated to the United States for binding and was powered by a nominal 90-day integrated battery supply. Applications using E Ink have since expanded, enabling smart designs for digital signage, electronic shelf labels, wearables, advantages of E Ink include low power usage, flexibility, durability and ruggedness and better readability under direct sunlight
35.
Plasma display
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A plasma display panel is a type of flat panel display common to large TV displays 30 inches or larger. They are called plasma displays because they use small cells containing electrically charged ionized gases, Plasma displays are bright, have a wide color gamut, and can be produced in fairly large sizes—up to 3.8 metres diagonally. They had a very low-luminance dark-room black level compared with the grey of the unilluminated parts of an LCD screen at least in the early history of the competing technologies. LED-backlit LCD televisions have been developed to reduce this distinction, the display panel itself is about 6 cm thick, generally allowing the devices total thickness to be less than 10 cm. The plasma that illuminates the screen can reach a temperature of at least 1200 °C, typical power consumption is 400 watts for a 127 cm screen. Most screens are set to shop mode by default, which draws at least twice the power of a setting of less extreme brightness. The lifetime of the latest generation of displays is estimated at 100,000 hours of actual display time. This is the time over which maximum picture brightness degrades to half the original value. Plasma screens are made out of glass. This may causes glare from reflected objects in the viewing area, currently, plasma panels cannot be economically manufactured in screen sizes smaller than 82 centimetres. Although a few companies have been able to make plasma enhanced-definition televisions this small, with the trend toward large-screen television technology, the 32 inch screen size is rapidly disappearing. Competing display technologies include cathode ray tube, organic light-emitting diode, AMLCD, Digital Light Processing DLP, SED-tv, LED display, field emission display, and quantum dot display. Capable of producing deeper blacks allowing for superior contrast ratio Wider viewing angles than those of LCD, images do not suffer from degradation at less than straight ahead angles like LCDs. LCDs using IPS technology have the widest angles, but they do not equal the range of plasma primarily due to IPS glow, LCD panel backlights nearly always produce uneven brightness levels, although this is not always noticeable. High-end computer monitors have technologies to try to compensate for the uniformity problem, unaffected by clouding from the polishing process. Some LCD panel types, like IPS, require a process that can introduce a haze usually referred to as clouding. Less expensive for the buyer per square inch than LCD, particularly when equivalent performance is considered, earlier generation displays were more susceptible to screen burn-in and image retention. Recent models have a pixel orbiter that moves the entire picture slower than is noticeable to the human eye, earlier generation displays had phosphors that lost luminosity over time, resulting in gradual decline of absolute image brightness. Newer models have advertised lifespans exceeding 100000 hours, far longer than older CRTs Uses more electrical power, on average, older CCFL backlights for LCD panels used quite a bit more power, and older plasma TVs used quite a bit more power than recent models
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Thin-film transistor
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A common substrate is glass, because the primary application of TFTs is in liquid-crystal displays. This differs from the transistor, where the semiconductor material typically is the substrate. TFTs can be using a wide variety of semiconductor materials. Other materials which have used as semiconductors in TFTs include compound semiconductors such as cadmium selenide. An application for hafnium oxide is as a high-κ dielectric, TFTs have also been made using organic materials, referred to as organic field-effect transistors or OTFTs. By using transparent semiconductors and transparent electrodes, such as tin oxide. Such transparent TFTs can be used for construction of video display panels, because conventional substrates cannot withstand high annealing temperatures, the deposition process must be completed under relatively low temperatures. Chemical vapor deposition and physical vapor deposition are applied, the first solution-processed TTFTs, based on zinc oxide, were reported in 2003 by researchers at Oregon State University. The Portuguese laboratory CENIMAT at the Universidade Nova de Lisboa has produced the world’s first completely transparent TFT at room temperature, CENIMAT also developed the first paper transistor, which may lead to applications such as magazines and journal pages with moving images. The best known application of transistors is in TFT LCDs. Transistors are embedded within the panel itself, reducing crosstalk between pixels and improving image stability, as of 2008, many color LCD TVs and monitors use this technology. TFT panels are used in digital radiography applications in general radiography. A TFT is used in direct and indirect capture as a base for the image receptor in medical radiography. AMOLED screens also contain a TFT layer, the most beneficial aspect of TFT technology is its use of a separate transistor for each pixel on the display. Because each transistor is small, the amount of charge needed to control it is also small and this allows for very fast re-drawing of the display. This picture does not include the actual light-source, just the TFT-display matrix
37.
Organic light-emitting diode
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An organic light-emitting diode is a light-emitting diode in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. This layer of organic semiconductor is situated between two electrodes, typically, at least one of these electrodes is transparent, OLEDs are used to create digital displays in devices such as television screens, computer monitors, portable systems such as mobile phones, handheld game consoles and PDAs. A major area of research is the development of white OLED devices for use in lighting applications. There are two families of OLED, those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates an electrochemical cell which has a slightly different mode of operation. OLED displays can use either passive-matrix or active-matrix addressing schemes, an OLED display works without a backlight, thus, it can display deep black levels and can be thinner and lighter than a liquid crystal display. In low ambient light conditions, an OLED screen can achieve a higher contrast ratio than an LCD, andré Bernanose and co-workers at the Nancy-Université in France made the first observations of electroluminescence in organic materials in the early 1950s. They applied high alternating voltages in air to such as acridine orange. The proposed mechanism was either direct excitation of the dye molecules or excitation of electrons, in 1960 Martin Pope and some of his co-workers at New York University developed ohmic dark-injecting electrode contacts to organic crystals. They further described the energetic requirements for hole and electron injecting electrode contacts. These contacts are the basis of charge injection in all modern OLED devices, the proposed mechanism was field-accelerated electron excitation of molecular fluorescence. Also in 1965, W. Helfrich and W. G and their proposed mechanism involved electronic excitation at the contacts between the graphite particles and the anthracene molecules. Roger Partridge made the first observation of electroluminescence from polymer films at the National Physical Laboratory in the United Kingdom, the device consisted of a film of poly up to 2.2 micrometers thick located between two charge injecting electrodes. The results of the project were patented in 1975 and published in 1983, hong Kong-born American physical chemist Ching W. Tang and his co-worker Steven Van Slyke at Eastman Kodak built the first practical OLED device in 1987. This was a revolution for the technology, Universal Display Corporation holds the majority of patents concerning the commercialization of OLEDs. A typical OLED is composed of a layer of organic materials situated between two electrodes, the anode and cathode, all deposited on a substrate, the organic molecules are electrically conductive as a result of delocalization of pi electrons caused by conjugation over part or all of the molecule. These materials have conductivity ranging from insulators to conductors, and are therefore considered organic semiconductors. The highest occupied and lowest unoccupied molecular orbitals of organic semiconductors are analogous to the valence, originally, the most basic polymer OLEDs consisted of a single organic layer
38.
Digital Light Processing
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Digital Light Processing is a display device based on optical micro-electro-mechanical technology that uses a digital micromirror device. It was originally developed in 1987 by Larry Hornbeck of Texas Instruments, while the DLP imaging device was invented by Texas Instruments, the first DLP-based projector was introduced by Digital Projection Ltd in 1997. Digital Projection and Texas Instruments were both awarded Emmy Awards in 1998 for the DLP projector technology, DLP technology is used in DLP front projectors, DLP rear projection television sets, and digital signs. It is also used in about 85% of digital cinema projection, smaller pico chipsets are used in mobile devices including cell phone accessories and projection display functions embedded directly into phones. In DLP projectors, the image is created by small mirrors laid out in a matrix on a semiconductor chip. These mirrors are so small that DMD pixel pitch may be 5.4 µm or less, each mirror represents one or more pixels in the projected image. The number of mirrors corresponds to the resolution of the projected image, 800×600, 1024×768, 1280×720, and 1920×1080 matrices are some common DMD sizes. These mirrors can be repositioned rapidly to light either through the lens or onto a heat sink. Rapidly toggling the mirror between these two orientations produces grayscales, controlled by the ratio of on-time to off-time, there are two primary methods by which DLP projection systems create a color image, those used by single-chip DLP projectors, and those used by three-chip projectors. A third method, sequential illumination by three colored light emitting diodes, is being developed, and is used in televisions manufactured by Samsung. The color wheel is divided into sectors, the primary additive colors, red, green, and blue. Newer systems substitute the primary subtractive colors cyan, magenta, the DLP chip is synchronized with the rotating motion of the color wheel so that the green component is displayed on the DMD when the green section of the color wheel is in front of the lamp. The same is true for the red, blue and other sections, the colors are thus displayed sequentially at a sufficiently high rate that the observer sees a composite full color image. In early models, this was one rotation per frame, now, most systems operate at up to 10x the frame rate. The black level of a single-chip DLP depends on how unused light is being disposed, DLP projectors utilizing a mechanical spinning color wheel may exhibit an anomaly known as the rainbow effect. Common examples are the end credits of many movies. Brief visible separation of the colours can also be apparent when the viewer moves their eyes quickly across the projected image, some people perceive these rainbow artifacts frequently, while others may never see them at all. This effect is caused by the way the eye follows an object on the projection
39.
Surface-conduction electron-emitter display
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A surface-conduction electron-emitter display is a display technology for flat panel displays developed by a number of companies. SEDs use nanoscopic-scale electron emitters to energize colored phosphors and produce an image, in a general sense, an SED consists of a matrix of tiny cathode ray tubes, each tube forming a single sub-pixel on the screen, grouped in threes to form red-green-blue pixels. SEDs combine the advantages of CRTs, namely their high contrast ratios, wide viewing angles and very fast response times, with the advantages of LCD. They also use less power than an LCD television of the same size. After considerable time and effort in the early and mid-2000s, SED efforts started winding down in 2009 as LCD became the dominant technology, in August 2010, Canon announced they were shutting down their joint effort to develop SEDs commercially, signalling the end of development efforts. SEDs are closely related to another developing display technology, the field emission display, or FED, sony, the main backer of FED, has similarly backed off from their development efforts. A conventional cathode ray tube is powered by an electron gun, at one end of the gun electrons are produced by boiling them off a metal filament, which requires relatively high currents and consumes a large proportion of the CRTs power. The electrons are accelerated and focused into a fast-moving beam. Electromagnets surrounding the gun end of the tube are used to steer the beam as it travels forward, when the fast-moving electrons strike phosphor on the back of the screen, light is produced. Color images are produced by painting the screen with spots or stripes of three colored phosphors, one each for red, green and blue. When viewed from a distance, the spots, known as sub-pixels, the SED replaces the single gun of a conventional CRT with a grid of nanoscopic emitters, one for each sub-pixel of the display. The emitter apparatus consists of a thin slit across which electrons jump when powered with high-voltage gradients, due to the nanoscopic size of the slits, the required field can correspond to a potential on the order of tens of volts. A few of the electrons, on the order of 3%, a second field, applied externally, accelerates these scattered electrons towards the screen. Production of this field requires kilovolt potentials, but is a constant field requiring no switching, each emitter is aligned behind a colored phosphor dot, and the accelerated electrons strike the dot and cause it to give off light in a fashion identical to a conventional CRT. Since each dot on the screen is lit by a single emitter, the quantum tunneling effect which emits electrons across the slits is highly non-linear, and the emission process tends to be fully on or off for any given voltage. The half power received by the rest of the emitters on the row is too small to cause emission, However, this also means that changes in voltage cannot be used to control the brightness of the resulting pixels. Instead, the emitters are rapidly turned on and off using pulse width modulation, SED screens consist of two glass sheets separated by a few millimeters, the rear layer supporting the emitters and the front the phosphors. In the SED, this also serves as the front electrode that accelerates the electrons toward the screen
40.
Carbon nanotube
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Carbon nanotubes are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. Owing to the exceptional strength and stiffness, nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000,1. In addition, owing to their thermal conductivity, mechanical. For instance, nanotubes form a portion of the material in some baseball bats, golf clubs. Nanotubes are members of the fullerene structural family and their name is derived from their long, hollow structure with the walls formed by one-atom-thick sheets of carbon, called graphene. Nanotubes are categorized as single-walled nanotubes and multi-walled nanotubes, individual nanotubes naturally align themselves into ropes held together by van der Waals forces, more specifically, pi-stacking. Applied quantum chemistry, specifically, orbital hybridization best describes chemical bonding in nanotubes, the chemical bonding of nanotubes is composed entirely of sp2 bonds, similar to those of graphite. These bonds, which are stronger than the sp3 bonds found in alkanes and diamond, most single-walled nanotubes have a diameter of close to 1 nanometer, and can be many millions of times longer. The structure of a SWNT can be conceptualized by wrapping a one-atom-thick layer of graphite called graphene into a seamless cylinder, the way the graphene sheet is wrapped is represented by a pair of indices. The integers n and m denote the number of unit vectors along two directions in the crystal lattice of graphene. If m =0, the nanotubes are called zigzag nanotubes, and if n = m, the diameter of an ideal nanotube can be calculated from its indices as follows d = a π =78.3 p m, where a =0.246 nm. SWNTs are an important variety of carbon nanotube because most of their properties change significantly with the values, in particular, their band gap can vary from zero to about 2 eV and their electrical conductivity can show metallic or semiconducting behavior. Single-walled nanotubes are likely candidates for miniaturizing electronics, the most basic building block of these systems is the electric wire, and SWNTs with diameters of an order of a nanometer can be excellent conductors. One useful application of SWNTs is in the development of the first intermolecular field-effect transistors, the first intermolecular logic gate using SWCNT FETs was made in 2001. A logic gate requires both a p-FET and an n-FET, because SWNTs are p-FETs when exposed to oxygen and n-FETs otherwise, it is possible to expose half of an SWNT to oxygen and protect the other half from it. The resulting SWNT acts as a not logic gate with both p and n-type FETs in the same molecule, prices for single-walled nanotubes declined from around $1500 per gram as of 2000 to retail prices of around $50 per gram of as-produced 40–60% by weight SWNTs as of March 2010. As of 2016 the retail price of as-produced 75% by weight SWNTs were $2 per gram, SWNTs are forecast to make a large impact in electronics applications by 2020 according to the The Global Market for Carbon Nanotubes report
41.
Quantum dot display
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A quantum dot display refers to the use of quantum dots, or semiconductor nanocrystals in manufacturing displays. The term carries multiple meanings, including the use of dots to emit light. At present, all commercial products such as TVs advertising quantum dot application branded as QLED are using them only to light for LCD backlights. Authentic quantum dot displays refer to a type of display technology. In these QLEDs, quantum dots or semiconductor nanocrystals could provide an alternative for applications as electro-optical display technology. However, such products are still experimental, the European Commission does not exempt the use of Cadmium for lighting to create these QLEDs. Properties and performance are determined by the size and/or composition of the QD, QDs are both photo-active and electro-active allowing them to be readily incorporated into new emissive display architectures. The idea of using quantum dot as a light source emerged in the 1990s, early applications included imaging using QD infrared photodetectors, light emitting diodes and single-color light emitting devices. Starting from early 2000, scientists started to realize the potential of developing quantum dot for light sources, a widespread practical application is emerging in so-called Quantum Dot TVs. It must be noted however, that these new TV sets are still LCD TVs as far as picture generation is concerned, unlike simple atomic structures, a quantum dot structure has the unusual property that energy levels are strongly dependent on the structures size. For example, CdSe quantum dot light emission can be tuned from red to the violet region, the physical reason for QD coloration is the quantum confinement effect and is directly related to their energy levels. The bandgap energy that determines the energy of the fluorescent light is proportional to the square of the size of quantum dot. Larger QDs have more levels that are more closely spaced. In other words, the photon energy increases as the dot size decreases. Quantum-dot-based LEDs are characterized by pure and saturated colors with narrow bandwidth. Their emission wavelength is tuned by changing the size of the quantum dots. Moreover, QD-LED offer high color purity and durability combined with the efficiency, flexibility, QD-LED structure can be tuned over the entire visible wavelength range from 460 nm to 650 nm. The emission wavelengths have been extended to UV and NIR range by tailoring the chemical composition of the QDs
42.
Multiplexed display
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Multiplexed displays are electronic display devices where the entire display is not driven at one time. The various segments of each character are connected in a diode matrix. For liquid crystal displays, the intersection of the row and column is not conductive at all, in the example of the VCR display shown above, the illuminated elements are the plates of many individual triode vacuum tubes sharing the same vacuum enclosure. The grids of the triodes are arranged so that only one digit is illuminated at a time, all of the similar plates in all of the digits are connected in parallel. One by one, the microprocessor driving the display enables a digit by placing a positive voltage on that digits grid, electrons flow through that digits grid and strike those plates that are at a positive potential. By multiplexing the display, only seven digit selector lines and seven segment selector lines are needed. The extra indicators are arranged as if they were segments of a digit or two or extra segments of existing digits and are scanned using the same multiplexed strategy as the real digits. Most character-oriented displays drive all the segments of an entire digit simultaneously. A few character-oriented displays drive only one segment at a time, the display on the Hewlett-Packard HP-35 was an example of this. The calculator took advantage of an effect of pulsed LED operation where very brief pulses of light are perceived as brighter than a pulse of light with the same time-integral of intensity. A keyboard matrix circuit has a similar arrangement as a multiplexed display. In order to reduce the number of even further, some people share wires between a multiplexed display and a keyboard matrix, reducing the number of wires even further. By comparison, in dot matrix displays, individual pixels are located at the intersections of the row and column lines. Here, the savings in wiring becomes far more dramatic, for a typical 1024x768 computer screen,2,359,296 wires would be needed for non-multiplexed control. That many wires would be completely impractical, but by arranging the pixels into a multiplexed matrix, only 1792 wires are needed, a completely practical situation. Pixel-oriented displays may drive a single pixel at a time or a row or column of pixels simultaneously. Active-matrix liquid crystal displays provide an element at each pixel so that the pixel continues to display the correct state even when not being actively driven. Because most multiplexed displays do not present the entire display simultaneously, for example, if the observer were to rapidly swing their vision across a multiplexed display, they might see a jumble of individual digits rather than a coherent display
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