Editing Output device (section)

== Visual ==
[[File:Ecran plat wikipedia.jpg|thumb|Monitor in use]]
{{Main|Electronic visual display}}
A ''display device'' is the most common form of output device which presents output visually on computer screen. The output appears temporarily on the screen and can easily be altered or erased.

With all-in-one PCs, notebook computers, hand held PCs and other devices; the term display screen is used for the display device. The display devices are also used in home entertainment systems, mobile systems, cameras and video game systems.

Display devices form images by illuminating a desired configuration of . Raster display devices are organized in the form of a 2-dimensional matrix with rows and columns. This is done many times within a second, typically 60, 75, 120 or 144&nbsp;Hz on consumer devices.

=== Interface ===

[[File:MSI MS-V328 outputs 20181231.jpg|thumb|left|Output interfaces on the rear of a graphics card]]

The interface between a computer's [[CPU]] and the display is a [[Graphics Processing Unit]] (GPU). This processor is used to form images on a [[framebuffer]]. When the image is to be sent to the display, the GPU sends its image through a [[video display controller]] to generate a [[video signal]], which is then sent to a [[List of video connectors|display interface]] such as [[HDMI]], [[VGA]], or [[DVI]]

GPUs can be divided into [[discrete GPU|discrete]] and [[integrated GPU|integrated]] units, the former being an external unit and the latter of which is included within a CPU die.<ref>{{Cite web|url=https://www.technipages.com/discrete-vs-integrated-graphics|title=Discrete vs Integrated Graphics|website=Technipages|date=22 July 2020 }}</ref> Discrete graphics cards are almost always connected to the host through the [[PCI Express]] bus, while older graphics cards may have used [[Accelerated Graphics Port|AGP]] or [[Peripheral Component Interconnect|PCI]]. Some mobile computers support an external graphics card through [[Thunderbolt (interface)|Thunderbolt]] (via PCIe).

=== Form factors ===

==== Monitor ====
{{Main|Computer monitor}}

A monitor is a standalone display commonly used with a [[desktop computer]], or in conjunction to a [[laptop]] as an external display. The monitor is connected to the host through the use of a display cable, such as [[HDMI]], [[DisplayPort]], [[VGA]], and more.

Older monitors use [[Cathode-ray tube|CRT]] technology, while modern monitors are typically [[flat panel display]]s using a plethora of technologies such as [[TFT-LCD]], [[LED]], [[OLED]], and more.

==== Internal display ====

Almost all mobile devices incorporate an internal display. These internal displays are connected to the computer through an internal display interface such as [[LVDS]] or [[Embedded DisplayPort|eDP]]. The chief advantage of these displays is their portability.

==== Terminal ====
[[File:Colossal Cave Adventure on VT100 terminal.jpg|thumb|[[Colossal Cave Adventure]] being played on a [[VT100]] terminal]]
{{Main|Computer terminal#VDUs}}

Prior to the development of modern pixel-oriented displays, [[computer terminals]] were used, composed of a character-oriented display device known as a ''VDU'' and a [[computer keyboard]].<ref>{{Cite web|url=https://www.pcmag.com/news/the-forgotten-world-of-dumb-terminals|title=The Forgotten World of Dumb Terminals|website=PCMag}}</ref>

These terminals were often monochromatic, and could only display text. Rudimentary graphics could be displayed through the use of [[ASCII art]] along with [[box-drawing character]]s. [[Teleprinter]]s were the precursors to these devices.

==== Projector ====
[[File:LED Projector machine.jpg|thumb|upright=0.8|An LED projector]]
{{Main|Video projector}}

A projector is a display that projects the computer image onto a surface through the use of a high power lamp. These displays are seen in use to show slideshow presentations or in movie screenings.<ref>{{Cite web|url=https://www.computerhope.com/jargon/p/projecto.htm|title=What is a Projector?|website=Computer Hope}}</ref>

=== Technologies ===
{{See also|Comparison of CRT, LCD, plasma, and OLED displays|Comparison of display technology}}

Display technologies can be classified based on working principle, lighting (or lack thereof), pixel layout, and more.

; [[Cathode-ray tube]] (CRT) : CRT screens produce an image using electron tube, which fires electrons at a phosphorous coated screen to light up pixels in order to display images.

; [[Liquid crystal display]] (LCD) : An LCD is a display technology employing the use of [[liquid crystal]]s to form images.

; [[Thin-film-transistor liquid crystal display|Thin-film transistor]] (TFT) : A TFT refers to the thin layer of transistors used with an LCD.

; [[LED-backlit LCD]] : An LCD display which uses [[LED]]s as a [[backlight]]. Prior to the use of LED based backlighting, [[Cold cathode#Lamps|Cold Cathode Fluorescent]] (CCFL) tubes were used. LED displays use an array of LEDs to form an image.

; [[Organic Light Emitting Diode]] (OLED) : Unlike an LED display, an OLED display does not use a backlight.

; [[Electronic paper]] (e-ink) : An e-ink display uses encapsulated pigment to form an image resembling printed paper, commonly used in [[e-book readers]].

=== Color output ===

==== Monochromatic display ====
A monochrome display is a type of CRT common in the early days of [[computing]], from the 1960s through the 1980s, before color monitors became popular.<ref>{{Cite news|url=https://www.elprocus.com/cathode-ray-tube/|title=Understanding of Cathode Ray Tube – CRT
|date=2013-10-26|work=ElProCus – Electronic Projects for Engineering Students|access-date=2018-09-15|language=en-US}}</ref>

They are still widely used in applications such as computerized cash register systems. Green screen was the common name for a monochrome monitor using a green "P1" phosphor screen.

==== Colored display ====
Color monitors, sometimes called [[RGB color model|RGB]] monitors, accept three separate signals (red, green, and blue), unlike a monochromatic display which accepts one. Color monitors implement the RGB color model by using three different phosphors that appear red, green, and blue when activated. By placing the phosphors directly next to each other, and activating them with different intensities, color monitors can create an unlimited number of colors. In practice, however, the real number of colors that any monitor can display is controlled by the [[Video card|video adapter]].<ref>{{Cite news|url=https://www.techwalla.com/articles/types-of-video-adapters|title=Types of Video Adapters {{!}} Techwalla.com|work=Techwalla|access-date=2018-09-15|language=en}}</ref>