Computer display
Overview
 
A monitor or display is an electronic visual display
Electronic visual display
An electronic visual display is display technology which incorporates flat panel displays, performs as a video display, output device for presentation of images transmitted electronically, for visual reception, without producing a permanent record....

 for computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

s. The monitor comprises the display device, circuitry
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...

, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) thin panel, while older monitors use a cathode ray tube
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

 about as deep as the screen size.

Originally, computer monitors were used for data processing
Data processing
Computer data processing is any process that a computer program does to enter data and summarise, analyse or otherwise convert data into usable information. The process may be automated and run on a computer. It involves recording, analysing, sorting, summarising, calculating, disseminating and...

 while television receivers were used for entertainment.
Encyclopedia
A monitor or display is an electronic visual display
Electronic visual display
An electronic visual display is display technology which incorporates flat panel displays, performs as a video display, output device for presentation of images transmitted electronically, for visual reception, without producing a permanent record....

 for computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

s. The monitor comprises the display device, circuitry
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...

, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) thin panel, while older monitors use a cathode ray tube
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

 about as deep as the screen size.

Originally, computer monitors were used for data processing
Data processing
Computer data processing is any process that a computer program does to enter data and summarise, analyse or otherwise convert data into usable information. The process may be automated and run on a computer. It involves recording, analysing, sorting, summarising, calculating, disseminating and...

 while television receivers were used for entertainment. From the 1980s onwards, computers (and their monitors) have been used for both data processing and entertainment, while televisions have implemented some computer functionality. The common aspect ratio
Aspect ratio
The aspect ratio of a shape is the ratio of its longer dimension to its shorter dimension. It may be applied to two characteristic dimensions of a three-dimensional shape, such as the ratio of the longest and shortest axis, or for symmetrical objects that are described by just two measurements,...

 of televisions, and then computer monitors, has also changed from 4:3 to 16:9.

Technologies

Different image techniques have been used for Computer monitors. Until the 21st century most monitors were CRT but they have been phased out for LCD monitors.

Cathode ray tube

The first computer monitors used cathode ray tube
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

s (CRT). Until the early 1980s, they were known as video display terminals and were physically attached to the computer and keyboard. The monitors were monochrome
Monochrome
Monochrome describes paintings, drawings, design, or photographs in one color or shades of one color. A monochromatic object or image has colors in shades of limited colors or hues. Images using only shades of grey are called grayscale or black-and-white...

, flickered and the image quality was poor. In 1981, IBM introduced the Color Graphics Adapter
Color Graphics Adapter
The Color Graphics Adapter , originally also called the Color/Graphics Adapter or IBM Color/Graphics Monitor Adapter, introduced in 1981, was IBM's first color graphics card, and the first color computer display standard for the IBM PC....

, which could display four colors with a resolution of 320 by 200 pixels. In 1984 IBM introduced the Enhanced Graphics Adapter
Enhanced Graphics Adapter
The Enhanced Graphics Adapter is the IBM PC computer display standard specification which is between CGA and VGA in terms of color and space resolution. Introduced in October 1984 by IBM shortly after its new PC/AT, EGA produces a display of 16 simultaneous colors from a palette of 64 at a...

 which was capable of producing 16 colors and had a resolution of 640 by 350.

CRT remained the standard for computer monitors through the 1990s. CRT technology remained dominant in the PC monitor market into the new millennium partly because it was cheaper to produce and offered viewing angles close to 180 degrees.

Liquid Crystal

There are multiple technologies that have been used to implement Liquid Crystal Displays (LCDs). Throughout the 1990s the primary use of LCD technology as computer monitors was in laptops where the lower power consumption, lighter weight, and smaller physical size of LCDs justified the higher price versus a CRT. Commonly, the same laptop would be offered with an assortment of display options at increasing price points (active or passive monochrome, passive color, active matrix color (TFT). As volume and manufacturing capability have improved the monochrome and passive color technologies were dropped from most product lines.

TFT is a variant of liquid crystal display
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....

 (LCD) which is now the dominant technology used for computer monitors.

The first standalone LCD displays appeared in the mid 1990s selling for high prices. As prices declined over a period of years they became more popular. During the 2000s TFT LCDs gradually displaced CRTs, eventually becoming the primary technology used for computer monitors. The main advantages of LCDs over CRT displays are that LCDs consume less power, take up much less space, and are considerably lighter. The now common active matrix TFT-LCD technology also has less flickering than CRTs, which reduces eye strain. On the other hand, CRT monitors have superior contrast, have superior response time, are able to use multiple screen resolutions natively, and there is no discernible flicker if the refresh rate is set to a sufficiently high value.

Organic light-emitting diode

Organic light-emitting diode
Organic light-emitting diode
An OLED is a light-emitting diode in which the emissive electroluminescent layer is a film of organic compounds which emit light in response to an electric current. This layer of organic semiconductor material is situated between two electrodes...

 (OLED) monitors provide higher contrast and better viewing angles than LCDs, and are predicted to replace them. In 2011 a 25 inch OLED monitor costs $6000, but the prices are expected to drop.

Performance measurements

The performance of a monitor is measured by the following parameters:
  • Luminance
    Luminance
    Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square...

     is measured in candelas per square meter (cd/m2 also called a Nit).
  • Aspect ratios
    Aspect ratio (image)
    The aspect ratio of an image is the ratio of the width of the image to its height, expressed as two numbers separated by a colon. That is, for an x:y aspect ratio, no matter how big or small the image is, if the width is divided into x units of equal length and the height is measured using this...

     is the ratio of the horizontal length to the vertical length. Monitors usually have the aspect ratio 4:3, 5:4, 16:10 or 16:9
    16:9
    16:9 is an aspect ratio with a width of 16 units and height of 9. Since 2009, it has become the most common aspect ratio for sold televisions and computer monitors and is also the international standard format of HDTV, Full HD, non-HD digital television and analog widescreen television ...

    .
  • Viewable image size
    Viewable image size
    On two-dimensional display devices such as computer monitors and television sets, the display size is the actual amount of screen space that is available to display a picture, video or working space, without obstruction from the case or other aspects of the unit's design...

     is usually measured diagonally, but the actual widths and heights are more informative since they are not affected by the aspect ratio in the same way. For CRTs, the viewable size is typically 1 in (25.4 mm) smaller than the tube itself.
  • Display resolution
    Display resolution
    The display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...

     is the number of distinct pixels in each dimension that can be displayed. Maximum resolution is limited by dot pitch.
  • Dot pitch
    Dot pitch
    Dot pitch is a specification for a computer display, computer printer, image scanner, or other pixel-based device that describes the distance, for example, between dots of the same color on the inside of a display screen...

     is the distance between subpixels of the same color in millimeters. In general, the smaller the dot pitch, the sharper the picture will appear.
  • Refresh rate
    Refresh rate
    The refresh rate is the number of times in a second that a display hardware draws the data...

     is the number of times in a second that a display is illuminated. Maximum refresh rate is limited by response time.
  • Response time
    Response time
    In technology, response time is the time a system or functional unit takes to react to a given input.- Data processing :In data processing, the response time perceived by the end user is the interval between the instant at which an operator at a terminal enters a request for a response from a...

     is the time a pixel in a monitor takes to go from active (white) to inactive (black) and back to active (white) again, measured in milliseconds. Lower numbers mean faster transitions and therefore fewer visible image artifacts.
  • Contrast ratio
    Contrast ratio
    The contrast ratio is a property of a display system, defined as the ratio of the luminance of the brightest color to that of the darkest color that the system is capable of producing...

     is the ratio of the luminosity of the brightest color (white) to that of the darkest color (black) that the monitor is capable of producing.
  • Power consumption is measured in watts.
  • Delta-E Colour accuracy is measured in delta-E; the lower the delta-E, the more accurate the colour representation. A delta-E of below 1 is imperceptible to the human eye. Delta-E’s of 2 to 4 are considered good and require a sensitive eye to spot the difference.
  • Viewing angle
    Viewing angle
    In display technology parlance, viewing angle is the maximum angle at which a display can be viewed with acceptable visual performance. In a technical context, this angular range is called viewing cone defined by a multitude of viewing directions....

     is the maximum angle at which images on the monitor can be viewed, without excessive degradation to the image. It is measured in degrees horizontally and vertically.

Size

On two-dimensional display devices such as computer monitors the display size or viewable image size is the actual amount of screen space that is available to display a picture, video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...

 or working space, without obstruction from the case or other aspects of the unit's design
Design
Design as a noun informally refers to a plan or convention for the construction of an object or a system while “to design” refers to making this plan...

. The main measurements for display devices are: width, height, total area and the diagonal.

The size of a display is usually by monitor manufacturers given by the diagonal i.e. the distance between two opposite screen corners. This method of measurement is inherited from the method used for the first generation of CRT television, when picture tubes with circular faces were in common use. Being circular, only their diameter was needed to describe their size. Since these circular tubes were used to display rectangular images, the diagonal measurement of the rectangle was equivalent to the diameter of the tube's face. This method continued even when cathode ray tubes were manufactured as rounded rectangles; it had the advantage of being a single number specifying the size, and was not confusing when the aspect ratio was universally 4:3.

The estimation of the monitor size by the distance between opposite corners does not take into account the display aspect ratio
Aspect ratio (image)
The aspect ratio of an image is the ratio of the width of the image to its height, expressed as two numbers separated by a colon. That is, for an x:y aspect ratio, no matter how big or small the image is, if the width is divided into x units of equal length and the height is measured using this...

, so that for example a 16:9 21 in (53.3 cm) widescreen
Widescreen
Widescreen images are a variety of aspect ratios used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ratio greater than the standard 1.37:1 Academy aspect ratio provided by 35mm film....

 display has less area
Area
Area is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...

, than a 21 in (53.3 cm) 4:3 screen. The 4:3 screen has dimensions of 16.8 × and area 211 sq in (1,361.3 cm²), while the widescreen is 18.3 ×, 188 sq in (1,212.9 cm²).

Aspect ratio

Until about 2003, most computer monitors had a 4:3 aspect ratio
Aspect ratio (image)
The aspect ratio of an image is the ratio of the width of the image to its height, expressed as two numbers separated by a colon. That is, for an x:y aspect ratio, no matter how big or small the image is, if the width is divided into x units of equal length and the height is measured using this...

 and some had 5:4. Between 2003 and 2006, monitors with 16:9
16:9
16:9 is an aspect ratio with a width of 16 units and height of 9. Since 2009, it has become the most common aspect ratio for sold televisions and computer monitors and is also the international standard format of HDTV, Full HD, non-HD digital television and analog widescreen television ...

 and mostly 16:10 (8:5) aspect ratios became commonly available, first in laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

s and later also in standalone monitors. Reasons for this transition was productive uses for such monitors, i.e. besides widescreen computer game play
Field of view in video games
Field of view in video games is the extent of the observable game world that is seen on the display at any given moment....

 and movie viewing, are the word processor display of two standard letter pages side by side, as well as CAD displays of large-size drawings and CAD application menus at the same time. 2008 16:10 became the most common sold aspect ratio for LCD monitors and the same year 16:10 was the mainstream standard for laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

s and notebook
Notebook
A notebook is a book or binder composed of pages of notes, often ruled, made out of paper, used for purposes including recording notes or memoranda, writing, drawing, and scrapbooking....

s.

In 2008 the computer industry started to move over from 16:10 to 16:9
16:9
16:9 is an aspect ratio with a width of 16 units and height of 9. Since 2009, it has become the most common aspect ratio for sold televisions and computer monitors and is also the international standard format of HDTV, Full HD, non-HD digital television and analog widescreen television ...

.

In 2011 non-widescreen displays with 4:3 aspect ratios were only being manufactured in small quantities. According to Samsung this was because the “Demand for the old 'Square monitors' has decreased rapidly over the last couple of years,” and “I predict that by the end of 2011, production on all 4:3 or similar panels will be halted due to a lack of demand.”

Resolution

The resolution for computer monitors have increased over time. From 320×200 during the early 80s, to 800×600 during the late 90s. As of 2011 the most common resolution is 1024x768 Gamers usually prefer higher resolutions, and, as of March 2011, 1920×1080 is their most common resolution.

Power saving

Most modern monitors will switch to a power-saving mode if no video-input signal is received. This allows modern operating systems to turn off a monitor after a specified period of inactivity. This also extends the monitor's service life.

Some monitors will also switch themselves off after a time period on standby.

Most modern laptops provide a method of screen dimming after periods of inactivity or when the battery is in use. This extends battery life and reduces wear.

Integrated accessories

Many monitors have other accessories (or connections for them) integrated. This places standard ports
Computer port (hardware)
In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices. Physically, a port is a specialized outlet on a piece of equipment to which a plug or cable connects...

 within easy reach and eliminates the need for another separate hub
USB hub
A USB hub is a device that expands a single USB port into several so that there are more ports available to connect devices to a host system.USB hubs are often built into equipment such as computers, keyboards, monitors, or printers...

, camera
Webcam
A webcam is a video camera that feeds its images in real time to a computer or computer network, often via USB, ethernet, or Wi-Fi.Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a video camera...

, microphone
Microphone
A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...

, or set of speakers
Computer speaker
Computer speakers, or multimedia speakers, are speakers external to a computer, that disable the lower fidelity built-in speaker. They often have a low-power internal amplifier. The standard audio connection is a 3.5 mm stereo jack plug often color-coded lime green for computer sound cards...

. These monitors have advanced microprocessors which contain codec information, Windows Interface drivers and other small software which help in proper functioning of these functions.

Glossy screen

Some displays, especially newer LCD monitors, replace the traditional anti-glare matte finish with a glossy one. This increases color saturation and sharpness but reflections from lights and windows are very visible.

Directional screen

Narrow viewing angle screens are used in some security conscious applications.

Polarized 3D monitor

The LG computer monitor 1920×1080 with screen 21.5-inches to 25-inches have feature the company's Film Pattern Retarder coating that ditches the heavy active shutter glasses used by many other manufacturers for the lighter passive variety will give flicker-free 3D. Although the screen is Full HD 1080p, but to see 3D images with 3D polarizing glasses we may only get a half portion of it (HD 720p) due to the pixels should be divided for the left and right eyes.

Autostereoscopic (3D) screen

A directional screen which generates 3D images without headgear.

Touch screen

These monitors use touching of the screen as an input method. Items can be selected or moved with a finger, and finger gestures may be used to convey commands. The screen will need frequent cleaning due to image degradation from fingerprints.

Tablet screens

A combination of a monitor with a graphics tablet
Graphics tablet
A graphics tablet is a computer input device that enables a user to hand-draw images and graphics, similar to the way a person draws images with a pencil and paper. These tablets may also be used to capture data or handwritten signatures...

. Such devices are typically unresponsive to touch without the use of one or more special tools' pressure. Newer models however are now able to detect touch from any pressure and often have the ability to detect tilt and rotation as well.

Touch and tablet screens are used on LCD displays as a substitute for the light pen, which can only work on CRTs.

Manufacturers

Acer AOC
AOC International
AOC International is the house brand of TPV Technology Limited , the world’s largest manufacturer of computer monitors. TPV Technology Limited is a Taiwan-based company. The group designs and produces a full range of CRT and TFT LCD monitors as well as LCD TVs for distribution...

 Apple Inc. Asus
ASUS
ASUSTeK Computer Incorporated is a multinational computer technology and consumer electronics product manufacturer headquartered in Taipei, Taiwan. Its product range includes motherboards, desktops, laptops, monitors, tablet PCs, servers and mobile phones...

 Belinea
Belinea
Belinea is a German manufacturer of PCs, notebooks and computer monitors.-History:The name Belinea was first used as a brand of computer monitors manufactured by Maxdata, which were primarily sold in Europe. The name first appeared in 1991. Belineas are known for their unique appearance with a big...

 BenQ
BenQ
BenQ Corporation is a Taiwanese multi-national company that sells and markets consumer electronics, computing and communications devices under the "BenQ" brand name, which stands for the company slogan Bringing Enjoyment and Quality to life .- Company :BenQ sells and markets technology products,...

 Chimei
Chimei
Chimei refers, as an umbrella term, to one of the two major agrarian rebellion movements against Wang Mang's Xin Dynasty, initially active in the modern Shandong and northern Jiangsu regions, that eventually led to Wang Mang's downfall by draining his resources, allowing the leader of the other...

 Dell
Dell
Dell, Inc. is an American multinational information technology corporation based in 1 Dell Way, Round Rock, Texas, United States, that develops, sells and supports computers and related products and services. Bearing the name of its founder, Michael Dell, the company is one of the largest...

 Eizo
Eizo
, or EIZO, is a manufacturer of high-end computer displays. A Japanese corporation, it was founded in March 1968 but did not adopt its current name until 1999 when Nanao Corporation and Eizo merged...


Gateway
Gateway, Inc.
Gateway Computer Corporation, is a computer hardware company headquartered in Irvine, California, USA which develops, manufactures, supports, and markets a wide range of personal computers, computer monitors, servers, and computer accessories...

 Hewlett-Packard
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...

 HannStar Display Corporation
HannStar Display Corporation
HannStar Display Corporation is a Taiwan-based technology company, primarily involved in the research and production of monitors, notebook displays, and televisions.-Overview:...

 IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

 Iiyama Corporation Kogan Technologies
Kogan Technologies
Kogan Technologies is an Australian manufacturer and retailer of consumer electronics devices. The company, founded in 2006 by Ruslan Kogan, sells products direct from Asia to customers in Australia and the United Kingdom....

 LG
LG
LG may refer to:*LG Corp., a South Korean electronics and petrochemicals conglomerate*LG Electronics, an affiliate of the South Korean LG Group which produces electronic products* Lawrence Graham, a London headquartered firm of business lawyers...

 NEC
NEC
, a Japanese multinational IT company, has its headquarters in Minato, Tokyo, Japan. NEC, part of the Sumitomo Group, provides information technology and network solutions to business enterprises, communications services providers and government....

 Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....


Planar Systems
Planar Systems
Planar Systems, Inc. is a U.S. digital display manufacturing corporation based in Hillsboro, Oregon. Founded in 1983 as a spin-off from Tektronix, it was the first U.S. manufacturer of electroluminescent digital displays. Planar also makes a variety of other specialty displays. The company, with...

 Samsung
Samsung
The Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...

 Sceptre Incorporated Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....

 Toshiba
Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...

 Tyco Electronics
Tyco Electronics
TE Connectivity, Ltd., previously known as Tyco Electronics, Ltd., and formerly a segment of Tyco International, is a leading global provider of engineered electronic components, network solutions, undersea telecommunication systems, and specialty products for customers in more than 150 countries...

 ViewSonic
ViewSonic
ViewSonic Corporation is a manufacturer and provider of visual technology, specifically CRT monitors, liquid crystal displays, projectors, plasma displays, HDTV technology, and mobile products, including Mini and All-in-One PCs and wireless monitors....

 Wortmann
Wortmann
Wortmann AG is a German computer manufacturer, based in Hüllhorst, North Rhine-Westphalia. The main products are computers, notebooks and servers, as well as computer monitors and thin clients. The majority of their products are assembled in Germany and are marketed under their own brand, "Terra"...

 Zalman
Zalman
Zalman Tech Co. is a Korean company that develops and provides aftermarket desktop computer products with primary focus on cooling enhancement....



See also

  • History of display technology
  • Flat panel display
    Flat panel display
    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 , and are usually less than thick...

  • Multi-monitor
  • Vector monitor
    Vector monitor
    A vector monitor or vector display is a display device used for early computers. It is a type of CRT, similar to the oscilloscope, but typically uses magnetic, rather than electrostatic, deflection...

  • Virtual desktop
    Virtual desktop
    In computing, a virtual desktop is a term used with respect to user interfaces, usually within the WIMP paradigm, to describe ways in which the size of a computer's desktop environment is expanded beyond the physical limits of the screen's real estate through the use of software, This saves space...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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