A flat-panel display (FPD) is an electronic
display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment.
Flat-panel displays are thin, lightweight, provide better linearity and are capable of higher resolution than typical consumer-grade TVs from earlier eras. They are usually less than thick. While the highest resolution for consumer-grade CRT televisions was
1080i, many flat-panel displays in the 2020s are capable of 1080p and
4K resolution.
In the 2010s, portable consumer electronics such as laptops, mobile phones, and portable cameras have used flat-panel displays since they consume less power and are lightweight. As of 2016, flat-panel displays have almost completely replaced CRT displays.
Most 2010s-era flat-panel displays use LCD or
light-emitting diode
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light ( ...
(LED) technologies, sometimes combined. Most LCD screens are
back-lit with color filters used to display colors. In many cases, flat-panel displays are combined with
touch screen technology, which allows the user to interact with the display in a natural manner. For example, modern smartphone displays often use
OLED
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 ...
panels, with
capacitive touch screens.
Flat-panel displays can be divided into two display device categories: volatile and static. The former requires that pixels be periodically electronically refreshed to retain their state (e.g.
liquid-crystal displays (LCD)), and can only show an image when it has power. On the other hand, static flat-panel displays rely on materials whose color states are bistable, such as displays that make use of
e-ink technology, and as such retain content even when power is removed.
History
The first engineering proposal for a flat-panel TV was by
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...
in 1954 as a result of its work on radar monitors. The 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. 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 and as an oscilloscope monitor, 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.
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.
Liquid-crystal Displays (LCDs)
The
MOSFET (metal-oxide-semiconductor field-effect transistor, or MOS transistor) was invented by
Mohamed M. Atalla and
Dawon Kahng at
Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984),
then AT&T Bell Laboratories (1984–1996)
and Bell Labs Innovations (1996–2007),
is an American industrial research and scientific development company owned by mult ...
in 1959,
and presented in 1960. Building on their work,
Paul K. Weimer at
RCA developed the
thin-film transistor (TFT) in 1962. It was a type of MOSFET distinct from the standard bulk MOSFET.
The idea of a TFT-based LCD was conceived by
Bernard J. Lechner
Bernard J. Lechner (25 January 1932 – 11 April 2014) was an electronics engineer and formerly vice president, RCA Laboratories, where he worked for 30 years covering various aspects of television and information display technologies.
Biogra ...
of
RCA Laboratories in 1968.
B.J. Lechner, F.J. Marlowe, E.O. Nester and J. Tults demonstrated the concept in 1968 with a
dynamic scattering LCD that used standard discrete MOSFETs.
The first
active-matrix addressed
electroluminescent display
Electroluminescent Displays (ELDs) are a type of flat panel display created by sandwiching a layer of electroluminescent material such as GaAs between two layers of conductors. When current flows, the layer of material emits radiation in the for ...
(ELD) was made using TFTs by
T. Peter Brody's Thin-Film Devices department at
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" i ...
in 1968. In 1973, Brody, J. A. Asars and G. D. Dixon at
Westinghouse Research Laboratories demonstrated the first
thin-film-transistor liquid-crystal display (TFT LCD).
Brody and Fang-Chen Luo demonstrated the first flat
active-matrix liquid-crystal display (AM LCD) using TFTs in 1974.
By 1982,
pocket LCD TVs based on LCD technology were developed in Japan. The 2.1-inch
Epson ET-10
''Epson Elf'' was the first color LCD pocket TV, released in 1984. In 1988, a
Sharp research team led by engineer T. Nagayasu demonstrated a 14-inch full-color LCD display,
which convinced the
electronics industry that LCD would eventually replace CRTs as the standard television
display technology.
, all modern
high-resolution and high-quality
electronic visual display devices use TFT-based active-matrix displays.
LED displays
The first usable LED display was developed by
Hewlett-Packard (HP) and introduced in 1968.
It was the result of
research and development
Research and development (R&D or R+D), known in Europe as research and technological development (RTD), is the set of innovative activities undertaken by corporations or governments in developing new services or products, and improving existi ...
(R&D) on practical
LED technology between 1962 and 1968, by a research team under Howard C. Borden, Gerald P. Pighini, and
Mohamed M. Atalla, at HP Associates and
HP Labs. In February 1969, they introduced the HP Model 5082-7000 Numeric Indicator.
It was the first alphanumeric LED display, and was a revolution in
digital display technology, replacing the
Nixie tube for numeric displays and becoming the basis for later LED displays. In 1977, James P Mitchell prototyped and later demonstrated what was perhaps the earliest monochromatic flat panel LED television display.
Ching W. Tang and
Steven Van Slyke at
Eastman Kodak built the first practical
organic LED (OLED) device in 1987.
In 2003,
Hynix produced an organic EL driver capable of lighting in 4,096 colors.
In 2004, the
Sony
, commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...
Qualia 005 was the first
LED-backlit LCD display. The
Sony XEL-1, released in 2007, was the first OLED television.
[Sony XEL-1:The world's first OLED TV](_blank)
, OLED-Info.com (17 November 2008).
Common types
Liquid-crystal display (LCD)
Field-effect LCDs are lightweight, compact, portable, cheap, more reliable, and easier on the eyes than CRT screens. LCD screens use a thin layer of liquid crystal, a liquid that exhibits crystalline properties. It is sandwiched between two glass plates carrying transparent electrodes. Two polarizing films are placed at each side of the LCD. By generating a controlled electric field between electrodes, various segments or pixels of the liquid crystal can be activated, causing changes in their polarizing properties. These polarizing properties depend on the alignment of the liquid-crystal layer and the specific field-effect used, being either
Twisted Nematic (TN),
In-Plane Switching (IPS) or
Vertical Alignment (VA). Color is produced by applying appropriate color filters (red, green and blue) to the individual subpixels. LCD displays are used in various electronics like watches, calculators, mobile phones, TVs, computer monitors and laptops screens etc.
LED-LCD
Most earlier large LCD screens were back-lit using a number of CCFL (cold-cathode fluorescent lamps). However, small pocket size devices almost always used LEDs as their illumination source. With the improvement of LEDs, almost all new displays are now equipped with
LED backlight technology. The image is still generated by the LCD layer.
Plasma panel
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. By 2010, consumer plasma displays had been discontinued by numerous manufacturers.
Electroluminescent panel
In an
electroluminescent display
Electroluminescent Displays (ELDs) are a type of flat panel display created by sandwiching a layer of electroluminescent material such as GaAs between two layers of conductors. When current flows, the layer of material emits radiation in the for ...
(ELD), the image is created by applying electrical signals to the plates which make the phosphor glow.
Organic light-emitting diode
An
OLED
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 ...
(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.
Quantum-dot light-emitting diode
QLED or quantum dot LED is a flat panel display technology introduced by Samsung under this trademark. Other television set manufacturers such as
Sony
, commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...
have used the same technology to enhance the backlighting of LCD TVs already in 2013.
''LG leaps quantum dot rivals with new TV.''
CNET, 16 December 2014. Retrieved 21 October 2017 Quantum dots create their own unique light when illuminated by a light source of shorter wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...
such as blue LEDs. This type of LED TV enhances the colour 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; Firms like Nanoco and Nanosys compete to provide the QD materials. In the meantime, Samsung Galaxy devices such as smartphones are still equipped with OLED displays manufactured by Samsung as well. Samsung explains 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
A power outage (also called a powercut, a power out, a power failure, a power blackout, a power loss, or a blackout) is the loss of the electrical power network supply to an end user.
There are many causes of power failures in an electrici ...
, 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
Liquid crystal on silicon (LCoS or LCOS) is a miniaturized reflective active-matrix liquid-crystal display or "microdisplay" using a liquid crystal layer on top of a silicon backplane. It is also referred to as a spatial light modulator. LCoS was ...
* Electronic paper
Electronic paper, also sometimes electronic ink, e-ink or electrophoretic display, are display devices that mimic the appearance of ordinary ink on paper. Unlike conventional flat panel displays that emit light, an electronic paper display ...
: E Ink
E Ink (electronic ink) is a brand of electronic paper (e-paper) display technology commercialized by the E Ink Corporation, which was co-founded in 1997 by MIT undergraduates JD Albert and Barrett Comiskey, MIT Media Lab professor Joseph Jacobson ...
, 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
Electroluminescent Displays (ELDs) are a type of flat panel display created by sandwiching a layer of electroluminescent material such as GaAs between two layers of conductors. When current flows, the layer of material emits radiation in the for ...
(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 toward slow refresh rates which are undesirable in an interactive display. Bistable flat-panel displays are beginning deployment in limited applications ( cholesteric liquid-crystal displays, manufactured by Magink, in outdoor advertising; electrophoretic displays in e-book reader devices from Sony and iRex; anlabels; interferometric modulator displays in a smartwatch).
See also
* Computer monitor
A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls.
The ...
* Display motion blur
* Electronic paper
Electronic paper, also sometimes electronic ink, e-ink or electrophoretic display, are display devices that mimic the appearance of ordinary ink on paper. Unlike conventional flat panel displays that emit light, an electronic paper display ...
* FPD-Link
Flat Panel Display Link, more commonly referred to as FPD-Link, is the original high-speed digital video interface created in 1996 by National Semiconductor (now within Texas Instruments). It is a free and open standard for connecting the outpu ...
* Flexible display
* Large-screen television technology
Large-screen television technology (colloquially big-screen TV) developed rapidly in the late 1990s and 2000s. Prior to the development of thin-screen technologies, rear-projection television was standard for larger displays, and jumbotron, a ...
* LCD
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 in ...
* LED-backlit LCD television
An LED-backlit LCD is a liquid-crystal display that uses LEDs for backlighting instead of traditional cold cathode fluorescent (CCFL) backlighting. LED-backlit displays use the same TFT LCD (thin-film-transistor liquid-crystal display) technol ...
* List of flat panel display manufacturers
* MicroLED
* Mobile display
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link while ...
* OLED
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 ...
* Plasma display panel
* Quantum dot display
* Sony Watchman
* Stereoscopy
Stereoscopy (also called stereoscopics, or stereo imaging) is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word ''stereoscopy'' derives . Any stereoscopic image i ...
3D displays requiring no special glasses
* Touch panel
* Transparent display
References
{{Authority control
American inventions
Display technology
Computer hardware
Television technology
Consumer electronics
Industrial equipment