Flat panel display

Flat panel TVs have existed since 1964, and are much thinner and lighter than televisions with picture tubes.

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.

Flat panel displays can be divided into two general display device 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.

History

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.[1]

The first production flat panel display was the Aiken tube, developed in the early 1950s and produced in limited numbers in 1958. This saw some use in military systems as a heads up display, but conventional technologies overtook its development. Attempts to commercialize the system for home television use ran into continued problems and the system was never released commercially.[2] The Philco Predicta featured a relatively flat (for its day) cathode ray tube setup and would be the first commercially released "flat panel" upon its launch in 1958; the Predicta was a commercial failure.

The plasma display panel was invented in 1964 at the University of Illinois, according to The History of Plasma Display Panels. [3]

The first-ever active-matrix addressed display was made by T Peter Brody's Thin-Film Devices department at Westinghouse Electric Corporation in 1968.[4]

As of 2012, 50% of global market share in flat panel display (FPD) production is by Taiwanese manufacturers such as AU Optronics and Chimei Innolux Corporation.

Common types

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 illuminated. 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 to the viewer. They are used in various electronics like watches, calculators, and notebook computers.

Liquid crystal displays with Light-emitting diodes (LED) A light-emitting diode (LED) display is a two-lead semiconductor light source that resembles a basic pn-junction diode, except that an LED also emits light. This form of LCD( liquid crystal) display is the most prevalent in use today. This form of LCD display is still a Liquid Crystal Display that uses a LED ( light emitting diode) backlight. It is not a separate technology from a LCD display.

Plasma panels

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.

Electroluminescent panels

In an electroluminescent display (ELD), the image is created by applying electrical signals to the plates which makes the phosphor glow.

Organic light-emitting diode

An OLED (organic light-emitting diode) is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound which 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 solid-state lighting applications.[1][2][3]

Volatile

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

Further information: Comparison CRT, LCD, Plasma

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

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).

See also

References

  1. ↑ "Proposed Television Sets Would Feature Thin Screens." Popular Mechanics, November 1954, p. 111.
  2. ↑ William Ross Aiken, "History of the Kaiser-Aiken, thin cathode ray tube", IEEE Transactions on Electron Devices, Volume 31 Issue 11 (November 1984), pp. 1605-1608.
  3. ↑ Plasma TV Science.org - The History of Plasma Display Panels
  4. ↑ 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.

External links

Wikimedia Commons has media related to Plasma displays.
Wikimedia Commons has media related to LCD computer monitors.
Wikimedia Commons has media related to LCD TVs.
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