Computer Monitors - CRT, LCD, LED, Plasma & OLED Display Monitors

We all are familiar with the computer monitors. We spend time sitting in front of them for hours working, gaming or watching movies. A monitor is used to display the output of any computer system. A good display makes all the difference and no doubt enhances the user experience. The innovation in the display technologies has improved the quality of the display devices including monitors. Now the desktop computers are available with a variety of displays ranging from technologically obsolete CRT monitors to latest slim LCD, LED or OLED monitors.
 
History
The first monitor dates long back in history. In the early stages of its evolution they were known as Terminals, Old Computer Monitorswhich were the boxy Video Display Terminals (VDTs). VDTs were monochrome monitors which used CRT (Cathode Ray Tube) technology. They were capable of working with any type of computer by connecting through a serial interface.
 
IBM’s CRT - IBM launched its first computer also known as a ‘three piece computer’ in 1981. It had three different units – CPU, monitor and keyboard separately. By 1984, IBM introduced the new CRT monitor with enhanced Color Graphics Adaptor (CGA) with 16 colors and a resolution of 640 x 350 pixels. In 1987 IBM started offering the Video Graphics Array as part of its new PCs which allowed 256 different colors and a resolution of 640 x 480 pixels.
 
XGA and UXGA – A new technology named Enhanced Graphics Array or XGA was introduced in 1990 which allowed 16.8 million colors with a resolution of 800 x 600 pixels. The new monitors were now offering true colors that matched the human eye (human eye can detect 10 million different colors). Later the technology extended as UXGA, Ultra Extended Graphics Array which allowed 1600 x 1200 pixels.

1.      Cathode Ray Tube (CRT) Monitors
These monitors employ the CRT technology to create a display. The CRT (also known as picture tube) receives the How CRT Monitors worksignals through a cable and the signal is decoded by the display controller which finally appears on a phosphor screen. The detailed working is as following:
 
As shown in the image CRTs have a conical shape and there is an electron gun or cathode ray gun at the back end of the monitor and a phosphor screen in the front. The electron gun fires a stream of electrons towards the display screen through a vacuum tube. This stream of electrons is also known as cathode rays. At the middle of the monitor, there are magnetic anodes which are magnetized in accordance with the instruction from the display controller. When electrons (cathode rays) pass through the magnetic anodes, they are pushed or pulled in one direction or other depending on the magnetic field on the anodes. This directs the electrons towards the correct part of phosphor coating inside the display glass. When electrons strikes the phosphor coated screen passing through a mesh (shadow mask or aperture grill), the phosphor lights up making a displayable dot on the computer screen. There are three different colored phosphors (Red, Green and Blue) for each pixel and the color of the pixel depends on the phosphor on which the electrons strike.

Plasma display

A plasma display panel (PDP) is a type of flat panel display common to large TV displays 30 inches (76 cm) or larger. They are called "plasma" displays because they use small cells containing electrically charged ionized gases, which are plasmas.
Plasma displays have lost nearly all market share, mostly due to competition from low-cost LCD and more expensive but high-contrast OLED flat-panel displays; manufacturing for the United States retail market ended in 2014, and manufacturing for the Chinese market was expected to end in 2016

Liquid crystal display

There are multiple technologies that have been used to implement liquid crystal displays (LCD). 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 LCD's 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, or active matrix color (TFT). As volume and manufacturing capability have improved, the monochrome and passive color technologies were dropped from most product lines.

Organic light-emitting diode

Organic light-emitting diode (OLED) monitors provide higher contrast and better viewing angles than LCD's but they require more power when displaying documents with white or bright backgrounds. In 2011, a 25-inch (64 cm) OLED monitor cost $7500, but the prices are expected to drop

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