MONITOR

What is a monitor?

A monitor or display (also called screen or visual display unit) is an electronic visual display for computers. The monitor comprises the display device, circuitry, 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 (CRT) about as deep as the screen size. Originally, computer monitors were used for data processing while television receivers were used for entertainment. This is an output device.

There are different types of monitors. They are:

1)      CRT monitors

2)      TFT monitors

3)      LCD monitors

4)      LED monitors

CRT monitor:

A cathode ray tube (CRT) monitor is an analog computer display or television set with a large, deep casing. This type of monitor uses streams of electrons that activate dots or pixels on the screen to create a full image.

Inside a CRT monitor is a picture tube that narrows at the rear into a bottleneck. In the bottleneck area is a charged filament or "cathode" enclosed in a vacuum tube. When electricity is supplied to this, the filament heats up and a stream or "ray" of electrons pours off of it. The negatively charged electrons are attracted to positively charged "anodes" which focus the particles into three narrow beams, accelerating them to strike a phosphor-coated display screen.

Phosphor glows when exposed to radiation, absorbing ultraviolet light and emitting visible, colored light. Materials that emit red, green and blue light are used in a color monitor, arranged as "stripes" made up of dots of color. The three beams are used to excite the three colors in combinations needed to create the various hues that form the picture.

There is another classification of CRT monitors. They are:

1)      Monochrome monitors

2)      Color monitors

Monochrome monitors:

Also known as monochromatic monitors, monochrome monitors are computer monitors that display a single color against a solid background. Used extensively during the middle to latter part of the 20th century, the monochrome monitor was at one time utilized with just about any type of computing system that included some sort of digital display. The first desktop computers developed in the latter part of the 1970s made use of this type of monitor. The monochrome monitor continued to be a staple in many office settings as late as the early 1990s, when it was finally eclipsed by the more feature-rich color monitor.

The effect of a monochrome monitor is somewhat like that of a black and white television set. The earliest designs called for a simple black background, with white text appearing on the screen. Some models reversed the process, using a white background to display black text. While somewhat plain, the use of a single phosphor to generate the single color in each pixel makes it possible for the monitor to provide a very clear and crisp looking display.

Color monitor:

A display monitor capable of displaying many colors. In contrast, a monochrome monitor can display only two colors -- one for the background and one for the foreground. 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 adapter.

TFT monitor:

A TFT monitor is a kind of LCD (Liquid Crystal Display) monitor that uses thin-film transistor (TFT) technology. As we are aware, LCD monitors are fast becoming the norm in place of cathode ray tube (CRT) monitors. While there are also other technologies in use, TFT is the technology most LCD monitors use.

In TFT technology, a separate miniscule transistor works for each pixel on the display. As the transistors are so tiny, the charge required to operate it is very small too. This way, the display gets refreshed several times per second, ensuring great visual clarity.

 In Passive Matrix LCD monitors that were in use before TFT, fast moving images could not be represented with adequate clarity. For instance, a body in motion from point A to point B would disappear between the two rest points. TFT could meet this challenge as each pixel is backed up with a transistor, and thus track the body throughout the screen. Thus TFT monitors are ideal for games, video displays and everything involving multimedia.

LCD monitor:

An LCD monitor is a thin, light computer monitor that displays images through the use of a liquid crystal display. LCD screens are found in most laptop computers as well as in flat panel monitors, and have replaced traditional cathode ray tube (CRT) monitors for many users. CRTs once were preferred by many users for their superior color presentation; improvements in LCDs have made the difference less noticeable, but still important to graphics and photography professionals and serious amateurs.

A color monitor is typically made up of five layers: a backlight, a sheet of polarized glass, a mask of colored pixels, a grid layer of responsive liquid crystal solution, and a second polarized sheet of glass. Images are created manipulating the orientation of the crystals through precise electrical charges of varying degrees and voltages. They act like tiny shutters, opening or closing in response to the stimulus, thereby allowing degrees of light that have passed through specific colored pixels to illuminate the screen.

LED monitors:

Led monitor is the new version of LCD monitor, which uses LEDs to illuminate the display. LED is a diode that emits light. It works like LCD but its backlight is different.  LED monitor use LED backlight replacing the standard cold cathode fluorescent lamps which was used in LCD monitor. It’s a new version of LCD by replacing backlight.

This is better than LCD because it needs less electricity than LCD. It is also better than plasma. LED monitor is thin than LCD and Plasma monitor. LED monitors are eco friendly too.