Video Display Devices in Computer Graphics


Display Devices in Computer Graphics

Display Devices in Computer Graphics

Computer Graphics generated pictures can be displayed on diversified display mediums called video display devices. The primary output device in a graphics system is a video monitor.

Basically, operation of the most video monitors is based on the cathode-ray tube design.

some display devices are given below:

1)     Cathode Ray Tube (CRT)

2)     Raster Scan Display 

3)     Random Scan Display

4)     Colour CRT Monitors

5)     Colour Generating Techniques

6)     Direct View Storage Tube (DVST)

7)     Plasma Panel Display

8)     Liquid Crystal Display (LCD)

Cathode Ray Tube (CRT)

This is a vacuum glass tube capable of converting a computer’s electrical signals into variable images at high speed.

Raster Scan Display 

In a raster-scan display, the electron beam is swept across the screen, one row at a time from top to bottom. As the electron beam moves across each row, the beam intensity is turned on and off to create a pattern of illuminated spots.

Random Scan Display

Random scan monitors draw a picture one line at a time and for this reason, are also referred to as vector displays (or stroke-writing or calligraphic displays). The component lines of a picture and refreshed by a random-scan system in any specified order.

Colour CRT Monitors

Color tubes use three different phosphors which emit red, green, and blue light respectively. They are packed together in stripes or clusters called “triads” (as in shadow mask CRTs)

Colour Generating Techniques

A color CRT monitor displays color pictures by using a combination of phosphors that emit different colored light. By combining the emitted light a range of colors can be generated.

Direct View Storage Tube (DVST)

The DVST is similar to the CRT, except that it does not need to be refreshed because the image in this is stored as a distribution of charges on the inside surface of the screen.

Plasma Panel Display

It is a device in which each pixel remains bright after it has been intensified. It is very similar to DVST though its construction is very difficult. Plasma pan display writes images on the display surface point by point, each point remains bright after it has been intensified.

Liquid Crystal Display (LCD)

It is a non-emissive device that produces a picture by passing polarized light through a liquid–crystal material that can be aligned to either block or transmit the light. LCD is given a name so, because the compound filled between the glass plates is a crystalline arrangement of molecules, hence they flow like a liquid.