Flat panel display

Last updated April 01, 2019

Flat-panel displays are electronic viewing technologies used to enable people to see content (still images, moving images, text, or other visual material) in a range of entertainment, consumer electronics, personal computer, and mobile devices, and many types of medical, transportation and industrial equipment. They are far lighter and thinner than traditional cathode ray tube (CRT) television sets and video displays and are usually less than 10 centimetres (3.9 in) thick. Flat-panel displays can be divided into two display device categories: volatile and static. Volatile displays require that pixels be periodically electronically refreshed to retain their state (e.g., liquid-crystal displays (LCD)). A volatile display only shows an image when it has battery or AC mains power. Static flat-panel displays rely on materials whose color states are bistable (e.g., e-book reader tablets from Sony), and as such, flat-panel displays retain the text or images on the screen even when the power is off. As of 2016, flat-panel displays have almost completely replaced old CRT displays. In many 2010-era applications, specifically small portable devices such as laptops, mobile phones, smartphones, digital cameras, camcorders, point-and-shoot cameras, and pocket video cameras, any display disadvantages of flat-panels (as compared with CRTs) are made up for by portability advantages (thinness and lightweightness).

An electronic visual display, informally a screen, is a display device for presentation of images, text, or video transmitted electronically, without producing a permanent record. Electronic visual displays include television sets, computer monitors, and digital signage. By the above definition, an overhead projector could reasonably be considered an electronic visual display since it is a display device for the presentation of an images, plain text, or video transmitted electronically without producing a permanent record. They are also ubiquitous in mobile computing applications like tablet computers, smartphones, and information appliances.

An image is an artifact that depicts visual perception, such as a photograph or other two-dimensional picture, that resembles a subject—usually a physical object—and thus provides a depiction of it. In the context of signal processing, an image is a distributed amplitude of color(s).

Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) systems which were later replaced by flat panel displays of several types.

Most 2010s-era flat-panel displays use LCD and/or LED technologies. Most LCD screens are back-lit as color filters are used to display colors. Flat-panel displays are thin and lightweight and provide better linearity and they are capable of higher resolution than typical consumer-grade TVs from earlier eras. The highest resolution for consumer-grade CRT TVs was 1080i; in contrast, many flat-panels can display 1080p or even 4K resolution. As of 2016, some devices that use flat-panels, such as tablet computers, smartphones and, less commonly, laptops, use touchscreens, a feature that enables users to select onscreen icons or trigger actions (e.g., playing a digital video) by touching the screen. Many touchscreen-enabled devices can display a virtual QWERTY or numeric keyboard on the screen, to enable the user to type words or numbers.

A backlight is a form of illumination used in liquid crystal displays (LCDs). As LCDs do not produce light by themselves—unlike, for example, cathode ray tube (CRT) displays—they need illumination to produce a visible image. Backlights illuminate the LCD from the side or back of the display panel, unlike frontlights, which are placed in front of the LCD. Backlights are used in small displays to increase readability in low light conditions such as in wristwatches, and are used in smart phones, computer displays and LCD televisions to produce light in a manner similar to a CRT display. A review of some early backlighting schemes for LCDs is given in a report Engineering and Technology History by Peter J. Wild.

1080i is an abbreviation referring to a combination of frame resolution and scan type, used in high-definition television (HDTV) and high-definition video. The number "1080" refers to the number of horizontal lines on the screen. The "i" is an abbreviation for "interlaced"; this indicates that only the odd lines, then the even lines of each frame are drawn alternately, so that only half the number of actual image frames are used to produce video. A related display resolution is 1080p, which also has 1080 lines of resolution; the "p" refers to progressive scan, which indicates that the lines of resolution for each frame are "drawn" in on the screen sequence.

1080p is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen vertically; the p stands for progressive scan, i.e. non-interlaced. The term usually assumes a widescreen aspect ratio of 16:9, implying a resolution of 2.1 megapixels. It is often marketed as full HD, to contrast 1080p with 720p resolution screens.

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, such as VGA input, HDMI input from a VHS VCR or video game console and, in some cases, a USB input or card reader for viewing digital photos). In many instances, an MFM also includes a TV tuner, making it similar to a LCD TV that offers computer connectivity.

HDMI is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital replacement for analog video standards.

A video game console is a computer device that outputs a video signal or visual image to display a video game that one or more people can play.

USB is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply between personal computers and their peripheral devices. Released in 1996, the USB standard is currently maintained by the USB Implementers Forum. There have been three generations of USB specifications: USB 1.x, USB 2.0 and USB 3.x; the fourth called USB4 is scheduled to be published in the middle of 2019.

History

The first engineering proposal for a flat-panel TV was by General Electric as a result of its work on radar monitors.^{[ when? ]} 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 active-matrix addressed display was made by T Peter Brody's Thin-Film Devices department at Westinghouse Electric Corporation in 1968.^[4] In 1977, James P Mitchell prototyped and later demonstrated what was perhaps the earliest monochromatic flat panel LED television display LED Display. As of 2012^[update], 50% of global market share in flat-panel display (FPD) production is by Taiwanese manufacturers such as AU Optronics and Chimei Innolux Corporation.

General Electric Company (GE) is an American multinational conglomerate incorporated in New York and headquartered in Boston. As of 2018, the company operates through the following segments: aviation, healthcare, power, renewable energy, digital industry, additive manufacturing, venture capital and finance, lighting, and oil and gas.

The Aiken tube was the first successful flat panel black and white television. Originally designed in the early 1950s, a small number of tubes were built in 1958 for military use in a collaboration with Kaiser Industries. An extended patent battle followed with a similar technology developed in the United Kingdom and planned commercial production for the home market never started. Further development was carried out by a number of companies, including Sinclair Electronics and RCA after the patents had expired.

Philco was a pioneer in battery, radio, and television production. In North America, it is the Philco brand owned by Philips. In other markets, it is the Philco International brand owned by Electrolux.

Common types

Liquid crystal displays

Liquid crystal displays (LCDs) are lightweight, compact, portable, cheap, more reliable, and easier on the eyes than cathode ray tube screens. LCD screens use a thin layer of liquid crystal, a liquid that exhibits crystalline properties. It is sandwiched between two electrically conducting plates. The top plate has transparent electrodes deposited on it, and the back plate is illuminated so that the viewer can see the images on the screen. By applying controlled 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 diode (LED) backlighting

Some LCD screens are backlit with a number of light-emitting diodes (LEDs). LEDs are 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 the 2010s. The image is still generated by the LCD.

Light-emitting diode semiconductor light source

A light-emitting diode (LED) is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. This effect is called electroluminescence. The color of the light is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.

A diode is a two-terminal electronic component that conducts current primarily in one direction ; it has low resistance in one direction, and high 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 common 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 materials such as gallium arsenide and germanium are used.

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. In the 2010s, plasma displays have been discontinued by numerous manufacturers.

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]

Quantum dot light emitting diode

QLED- QLED or Quantum Dot LED is a flat panel display technology introduced by Samsung under this trademark. Other television set manufacturers such as Sony have used the same technology to enhance the backlighting of LCD Television already in 2013.^[5]^[6] Quantum dots create their own unique light when illuminated by a light source of shorter wavelength such as blue LEDs. This type of LED TV introduced by Samsung enhances the color gamut of LCD panels, where the image is still generated by the LCD. In the view of Samsung, quantum dot displays for large-screen TVs are expected to become more popular than the OLED displays in the coming years. This is surprising because Samsung Galaxy devices such as smartphones are mainly equipped with OLED displays manufactured by Samsung as well. Samsung states on their website that the QLED TV they produce can determine what part of the display needs more or less contrast. Samsung also announced a partnership with Microsoft that will promote the new Samsung QLED TV.

Volatile

Volatile displays require that pixels be periodically refreshed to retain their state, even for a static image. As such, a volatile screen needs electrical power, either from mains electricity (being plugged into a wall socket) or a battery to maintain an image on the display or change the image. This refresh typically occurs many times a second. If this is not done, for example, if there is a power outage, the pixels will gradually lose their coherent state, and the image will "fade" from the screen.

Examples

The following flat-display technologies have been commercialized in 1990s to 2010s:

Plasma display panel (PDP)
Active-matrix liquid-crystal display (AMLCD)
Rear projection: Digital Light Processing (DLP), LCD, LCOS
Electronic paper: E Ink, Gyricon
Light-emitting diode display (LED)
Active-matrix organic light-emitting diode (AMOLED)
Quantum dot display (QLED)

Technologies that were extensively researched, but their commercialization was limited or has been ultimately abandoned:

Active-matrix Electroluminescent display (ELD)
Interferometric modulator display (IMOD)
Field emission display (FED)
Surface-conduction electron-emitter display (SED, SED-TV)

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 reader devices from Sony and iRex; anlabels).

Related Research Articles

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. Liquid crystals do not emit light directly, instead using a backlight or reflector to produce images in color or monochrome. LCDs are available to display arbitrary images or fixed images with low information content, which can be displayed or hidden, such as preset words, digits, and seven-segment displays, as in a digital clock. 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 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 color of the backlight, and a character negative LCD will have a black background with the letters being of the same color as the backlight. Optical filters are added to white on blue LCDs to give them their characteristic appearance.

A plasma display panel (PDP) is a type of flat panel display that uses small cells containing plasma; ionized gas that responds to electric fields.

An organic light-emitting diode (OLED) 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, portable systems such as smartphones, handheld game consoles and PDAs. A major area of research is the development of white OLED devices for use in solid-state lighting applications.

Display may refer to:

Display device output device for presentation of information in visual form

A display device is an output device for presentation of information in visual or tactile form. When the input information that is supplied has an electrical signal, the display is called an electronic display.

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.

A television set or television receiver, more commonly called a television, TV, TV set, 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 sets became a popular consumer product after World War II in electronic form, using cathode ray tubes. The addition of color to broadcast television after 1953 further increased the popularity of television sets in the 1960s, and an outdoor antenna became a common feature of suburban homes. 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 and video game consoles in the 1980s. 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 high-definition display and can also play content from a USB device.

LCD television television sets that use liquid-crystal displays to produce images

Liquid-crystal-display televisions are television sets that use liquid-crystal displays to produce images. They are, by far, the most widely produced and sold television display type. LCD TVs are thin and light, but have some disadvantages compared to other display types such as high power consumption, poorer contrast ratio, and inferior color gamut.

A surface-conduction electron-emitter display (SED) 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 (RGB) pixels. SEDs combine the advantages of CRTs, namely their high contrast ratios, wide viewing angles and very fast response times, with the packaging advantages of LCD and other flat panel displays. They also use much less power than an LCD television of the same size.

This is a comparison of various properties of different display technologies.

Large-screen television technology developed rapidly in the late 1990s and 2000s. Various thin screen technologies are being developed, but only the liquid crystal display (LCD), plasma display (PDP) and Digital Light Processing (DLP) have been released on the public market. A video display that uses large-screen television technology is called a jumbotron. These technologies have almost completely displaced cathode ray tubes (CRT) in television sales, due to the necessary bulkiness of cathode ray tubes. However, recently released technologies like organic light-emitting diode (OLED) and not-yet released technologies like surface-conduction electron-emitter display (SED) or field emission display (FED) are making their way to replace the first flat screen technologies in picture quality. The diagonal screen size of a CRT television is limited to about 40 inches because of the size requirements of the cathode ray tube, which fires three beams of electrons onto the screen, creating a viewable image. A larger screen size requires a longer tube, making a CRT television with a large screen unrealistic because of size. The aforementioned technologies can produce large-screen televisions that are much thinner.

Rear-projection television (RPTV) is a type of large-screen television display technology. Until approximately 2006, most of the relatively affordable consumer large screen TVs up to 100 in (250 cm) used rear-projection technology. A variation is a video projector, using similar technology, which projects onto a screen.

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 where they are visible in the sun for store signs and billboards. In recent years, they have also become commonly used in destination signs on public transport vehicles, as well as variable-message signs on highways. LED displays are capable of providing general illumination in addition to visual display, as when used for stage lighting or other decorative purposes.

Digital newspaper technology is the technology used to create or distribute a digital newspaper.

A LED-backlit LCD is a flat panel display which uses LED backlighting instead of the cold cathode fluorescent (CCFL) backlighting. LED-backlit displays use the same TFT LCD technologies as CCFL-backlit displays, but offer reduced energy consumption, better contrast and brightness, greater color range, more rapid response to changes in scene, and photorefractive effects.

Electrically operated display devices have developed from electromechanical systems for display of text, up to all-electronic devices capable of full-motion 3D color graphic displays. Electromagnetic devices, using a solenoid coil to control a visible flag or flap, were the earliest type, and were used for text displays such as stock market prices and arrival/departure display times. The cathode ray tube was the workhorse of text and video display technology for several decades until being displaced by plasma, liquid crystal (LCD) and solid-state devices such as LEDs and OLEDs. With the advent of microprocessors and microelectronic devices, many more individual picture elements ("pixels") could be incorporated into one display device, allowing graphic displays and video.

Quantum dot display display device that uses quantum dots (QD), semiconductor nanocrystals which can produce pure monochromatic red, green, and blue light.

A quantum dot display is a display device that uses quantum dots (QD), semiconductor nanocrystals which can produce pure monochromatic red, green, and blue light.

IPS is a screen technology for liquid-crystal displays (LCDs). It was designed to solve the main limitations of the twisted nematic field effect (TN) matrix LCDs which were prevalent in the late 1980s. These limitations included strong viewing angle dependence and low-quality color reproduction. In-plane switching involves arranging and switching the orientation of the molecules of the liquid crystal (LC) layer between the glass substrates. This is done, essentially, parallel to these glass plates.

References

↑ "Proposed Television Sets Would Feature Thin Screens." Popular Mechanics, November 1954, p. 111.
↑ 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.
↑ 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.
↑ CES 2015 placing bets on new TV technologies. IEEE Spectrum, January 7, 2015. Retrieved October 21, 2017
↑ LG leaps quantum dot rivals with new TV. CNET, December 16, 2014. Retrieved October 21, 2017

External links

TFT Central, flat panel monitor reviews, news and articles
LED display, LED display system in China
Finetech Japan, FDP exhibition and conference
Feature: Strange Inventions You Never Knew About

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[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.

[5] CES 2015 placing bets on new TV technologies. IEEE Spectrum, January 7, 2015. Retrieved October 21, 2017

[6] LG leaps quantum dot rivals with new TV. CNET, December 16, 2014. Retrieved October 21, 2017