Flat panel display
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Flat panel displays encompass a growing number of electronic visual display technologies. They are far lighter and thinner than traditional television sets and video displays that use cathode ray tubes (CRTs), and are usually less than 10 centimetres (3.9 in) thick. (Some CRTs were designed to have a flat front surface, and equipment using them was advertised as "flat-screen", which can cause confusion.)
Flat panel displays can be divided into two general display technology categories: volatile and static.
In many applications, specifically modern portable devices such as laptops, mobile phones, digital cameras, camcorders, point-and-shoot cameras, and pocket video cameras, any display disadvantages are made up for by portability advantages.
Most of the modern flat-panel displays use LCD technologies. Most LCD screens are back-lit to make them easier to read in bright environments. They are thin and light. They provide better linearity and higher resolution.
A multifunctional monitor (MFM) is a flat panel display that has additional video inputs (more than a typical LCD monitor) and is designed to be used with a variety of external video sources. In many instances, an MFM also includes a TV tuner, making it similar to a LCD TV that offers computer connectivity.
The first engineering proposal for a flat panel TV was by General Electric as a result of its work on radar monitors. Their publication of their findings gave all the basics of future flat panel TVs and monitors. But GE did not continue with the R&D required and never built a working flat panel at that time.
Liquid crystal displays
Liquid crystal displays are lightweight, compact, portable, cheap, more reliable, and easier on the eyes than CRTs. A thin layer of liquid crystal, a liquid that exhibits crystalline properties, is sandwiched between two electrically conducting plates.The top plate has transparent electrodes deposited on it, and the back plate is a mirror. By applying proper electrical signals across the plates, various segments of the liquid crystal can be activated, causing changes in their light diffusing or polarizing properties. These segments can either transmit or block light. An image is produced by passing light through selected segments of the liquid crystal and then reflected it back from the mirror to the viewer. They are used in various electronics like watches, calculators, and notebook computers.
A plasma display consists of two glass plates separated by a thin gap filled with a gas such as neon. Each of these plates has several parallel electrodes running across it. The electrodes on the two plates are at right angles to each other. A voltage applied between the two electrodes one on each plate causes a small segment of gas at the two electrodes to glow. The glow of gas segments is maintained by a lower voltage that is continuously applied to all electrodes.
In an electroluminescent display (ELD), the image is created by applying electrical signals to the plates which makes the phosphor glow.
Volatile displays require that pixels be periodically refreshed to retain their state, even for a static image. This refresh typically occurs many times a second. If this is not done, the pixels will gradually lose their coherent state, and the image will "fade" from the screen.
Examples of volatile flat panel displays
- Active-matrix liquid-crystal display (AMLCD)
- Electronic paper: E Ink, Gyricon
- Electroluminescent display (ELD)
- Digital Light Processing (DLP)
- Field emission display (FED), also named nano-emissive display (NED)
- Interferometric modulator display (IMOD)
- Light-emitting diode display (LED)
- Liquid-crystal display (LCD)
- Organic light-emitting diode (OLED)
- Plasma display panel (PDP)
- Quantum dot display (QLED)
- Surface-conduction electron-emitter display (SED, SED-TV)
Only a few of these displays are commercially available today, though OLED displays are beginning deployment only in small sizes, mainly in cellular telephones.
Static flat panel displays rely on materials whose color states are bistable. This means that the image they hold requires no energy to maintain, but instead requires energy to change. This results in a much more energy-efficient display, but with a tendency towards slow refresh rates which are undesirable in an interactive display.
Bistable flat panel displays are beginning deployment in limited applications (Cholesteric displays, manufactured by Magink, in outdoor advertising; electrophoretic displays in e-book products from Sony and iRex; anlabels).
- Computer monitor
- Electronic paper
- Flexible display
- Large-screen television technology
- LED-backlit LCD television
- Display motion blur
- Mobile display
- Sony Watchman
- Stereoscopy 3D displays requiring no special glasses
- Touch panel
- Transparent display
- "Proposed Television Sets Would Feature Thin Screens." Popular Mechanics, November 1954, p. 111.
- Plasma TV Science.org - The History of Plasma Display Panels
- Castellano, Joseph A. (2005). Liquid gold: the story of liquid crystal displays and the creation of an industry ([Online-Ausg.] ed.). New Jersey [u.a.]: World Scientific. p. 176. ISBN 981-238-956-3.
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