Graphical Devices

Introduction:
The Graphics system are used to display picture with fast interactive response . so that it is basically needs two things first hardware and second software , hardware includes all type of hard ware as input. out and process. The standard input device that used in computer graphics system are as:
1. Alphanumeric Key Board.
2. Multimedia key board or programmed key
3. Mouse / Track Ball / Track space.
4. Scanner system (OCR,OMR,MICR,BCR)
5. Light pen
6. Digitizer
7. Joystick
8. Data Glove
9. Touch Screen
10. Voice System(microphone
11. Web Cam

Standard output devices as:
1. Monitor
2. Printer
3. Plotter
4. Sound System

Raster Scan Display :
To maintaining the picture display on the CRT screen use a special technique that called Raster scan display.
Horizontal retrace : When electron beam move across the row and one row to another row is called Horizontal retrace.
Vertical retrace: When electron beam move across the screen vertically and at last reach the bottom of the screen then electron beam set the top row of the screen this jump is called vertical retrace.

Color CRT Monitor :

A CRT monitor display color picture by using the combination of different type of phosphor that emit different type color light.
(1) Beam penetration method
(2) shadow mask method

(1) Beam penetration Method:
The Beam Penetration method displaying color picture has been used with random scan monitor.CRT screen coated by two layer of phosphor usually red and green.This method is very easy to implement but have some disadvantage it can display maximum color .

(2) shadow mask method
CRT screen coated the set of three dot of color phosphor respectively red . green 7 blue phosphor dot in triangular shape, It have three electron guns.


Composite CRT Monitor :

direct View Storage Tube (DVST)
Flat Panel display
Plasma Panel
Thin -Film electroluminescent display
LED display
Liquid Crystal display device