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Active-matrix Liquid-crystal Display
An active-matrix liquid-crystal display (AMLCD) is a type of flat-panel display, the only viable technology for high-resolution TVs, computer monitors, notebook computers, tablet computers and smartphones with an LCD screen, due to low weight, very good image quality, wide color gamut and response time. The concept of active-matrix LCDs was proposed by Bernard J. Lechner at the RCA Laboratories in 1968. The first functional AMLCD with thin-film transistors was made by T. Peter Brody, Fang-Chen Luo and their team at Westinghouse Electric Corporation in 1972. However, it took years of additional research and development by others to launch successful products. Introduction The most common type of AMLCD contains, besides the polarizing sheets and cells of liquid crystal, a matrix of thin-film transistors to make a thin-film-transistor liquid-crystal display. These devices store the electrical state of each pixel on the display while all the other pixels are being updated. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Matrix
Active matrix is a type of addressing scheme used in flat panel displays. In this method of switching individual elements (pixels), each pixel is attached to a transistor and capacitor ''actively'' maintaining the pixel state while other pixels are being addressed, in contrast with the older passive matrix technology in which each pixel must maintain its state passively, without being driven by circuitry. Active matrix technology was invented by Bernard J. Lechner at RCA, using MOSFETs (metal-oxide-semiconductor field-effect transistors). Active matrix technology was first demonstrated as a feasible device using thin-film transistors (TFTs) by T. Peter Brody, Fang Chen Luo and their team at the Thin-Film Devices department of Westinghouse Electric Corporation in 1974, and the term was introduced into the literature in 1975. Given an ''m'' × ''n'' matrix, the number of connectors needed to address the display is ''m'' + ''n'' (just like in passive matrix techn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thin-film Transistor
A thin-film transistor (TFT) is a special type of field-effect transistor (FET) where the transistor is thin relative to the plane of the device. TFTs are grown on a supporting (but non-conducting) substrate. A common substrate is glass, because the traditional application of TFTs is in liquid-crystal displays (LCDs). This differs from the conventional bulk metal oxide field effect transistor (MOSFET), where the semiconductor material typically ''is'' the substrate, such as a silicon wafer. Design and Manufacture TFTs can be fabricated with a wide variety of semiconductor materials. Because it is naturally abundant and well understood, amorphous or polycrystalline silicon was historically used as the semiconductor layer. However, because of the low mobility of amorphous silicon and the large device-to-device variations found in polycrystalline silicon, other materials have been studied for use in TFTs. These include cadmium selenide, metal oxides such as indium gallium zi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active-matrix Organic Light-emitting Diode
AMOLED (active-matrix organic light-emitting diode, ) is a type of OLED display device technology. OLED describes a specific type of thin-film-display technology in which organic compounds form the electroluminescent material, and active matrix refers to the technology behind the addressing of pixels. Since 2007, AMOLED technology has been used in mobile phones, media players, TVs and digital cameras, and it has continued to make progress toward low-power, low-cost, high resolution and large size (for example, 88-inch and 8K resolution) applications. Design An AMOLED display consists of an active matrix of OLED pixels generating light (luminescence) upon electrical activation that have been deposited or integrated onto a thin-film transistor (TFT) array, which functions as a series of switches to control the current flowing to each individual pixel. Typically, this continuous current flow is controlled by at least two TFTs at each pixel (to trigger the luminescence), with o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Light-emitting Diode
An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. This organic layer 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, and portable systems such as smartphones and handheld game consoles. A major area of research is the development of white OLED devices for use in solid-state lighting applications. There are two main families of OLED: those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates a light-emitting electrochemical cell (LEC) which has a slightly different mode of operation. An OLED display can be driven with a passive-matrix (PMOLED) or active-matrix (AMOL ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sample-and-hold
In electronics, a sample and hold (also known as sample and follow) circuit is an analog device that samples (captures, takes) the voltage of a continuously varying analog signal and holds (locks, freezes) its value at a constant level for a specified minimum period of time. Sample and hold circuits and related peak detectors are the elementary analog memory devices. They are typically used in analog-to-digital converters to eliminate variations in input signal that can corrupt the conversion process.Kefauver and Patschke, p. 37. They are also used in electronic music, for instance to impart a random quality to successively-played notes. A typical sample and hold circuit stores electric charge in a capacitor and contains at least one switching device such as a FET (field effect transistor) switch and normally one operational amplifier.Horowitz and Hill, p. 220. To sample the input signal, the switch connects the capacitor to the output of a buffer amplifier. The buffer ampli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diode
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used. Among many uses, diodes are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passive Matrix
Passive matrix addressing is an addressing scheme used in early LCDs. This is a matrix addressing scheme meaning that only ''m'' + ''n'' control signals are required to address an ''m'' × ''n'' display. A pixel in a passive matrix must maintain its state without active driving circuitry until it can be refreshed again. The signal is divided into a row or ''select signal'' and a column or ''video signal''. The select voltage determines the row that is being addressed and all ''n'' pixels on a row are addressed simultaneously. When pixels on a row are being addressed, a ''Vsel'' potential is applied, and all other rows are unselected with a ''Vunsel'' potential. The video signal or column potential is then applied with a potential for each ''m'' columns individually. An on-switched (lit) pixel corresponds to a ''Von'', an off-switched (unlit) corresponds to a ''Voff'' potential. The potential across pixel at selected row ''i'' and column ''j'' is :V_ = V_ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the smallest element that can be manipulated through software. Each pixel is a sample of an original image; more samples typically provide more accurate representations of the original. The intensity of each pixel is variable. In color imaging systems, a color is typically represented by three or four component intensities such as red, green, and blue, or cyan, magenta, yellow, and black. In some contexts (such as descriptions of camera sensors), ''pixel'' refers to a single scalar element of a multi-component representation (called a ''photosite'' in the camera sensor context, although '' sensel'' is sometimes used), while in yet other contexts (like MRI) it may refer to a set of component intensities for a spatial position. Etymology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thin-film-transistor Liquid-crystal Display
A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven (i.e. with segments directly connected to electronics outside the LCD) LCDs with a few segments. TFT LCDs are used in appliances including television sets, computer monitors, mobile phones, handheld devices, video game systems, personal digital assistants, navigation systems, projectors, and dashboards in automobiles. History In February 1957, John Wallmark of RCA filed a patent for a thin film MOSFET. Paul K. Weimer, also of RCA implemented Wallmark's ideas and developed the thin-film transistor (TFT) in 1962, a type of MOSFET distinct from the standard bulk MOSFET. It was made with thin films of cadmium selenide and cadmium sulfide. The idea of a TFT-based liquid-crystal disp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Westinghouse Electric Corporation
The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in 1945. The company acquired the CBS television network in 1995 and was renamed "CBS Corporation" until being acquired by Viacom in 1999, a merger completed in April 2000. The CBS Corporation name was later reused for one of the two companies resulting from the split of Viacom in 2006. The Westinghouse trademarks are owned by Westinghouse Electric Corporation, and were previously part of Westinghouse Licensing Corporation. The nuclear power business, Westinghouse Electric Company, was spun off from the Westinghouse Electric Corporation in 1999. History Westinghouse Electric was founded by George Westinghouse in Pittsburgh, Pennsylvania, on January 8, 1886. The firm became active in developing electric infrastructure throughout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute Of Electrical And Electronics Engineers
The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operations center in Piscataway, New Jersey. The mission of the IEEE is ''advancing technology for the benefit of humanity''. The IEEE was formed from the amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers in 1963. Due to its expansion of scope into so many related fields, it is simply referred to by the letters I-E-E-E (pronounced I-triple-E), except on legal business documents. , it is the world's largest association of technical professionals with more than 423,000 members in over 160 countries around the world. Its objectives are the educational and technical advancement of electrical and electronic engineering, telecommunications, computer engineering and similar disciplines. History Orig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid-crystal Display
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but instead use a backlight or reflector to produce images in color or monochrome. LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images with low information content, which can be displayed or hidden. For instance: preset words, digits, and seven-segment displays, as in a digital clock, are all good examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs can either be normally on (positive) or off (negative), depending on the polarizer arrangement. For example, a character positive LCD with a backlight will have black lettering on a background that is the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
