It is technology which is used as an output device for the presentation of visual information.

For eg:

Color CRT Monitors

Flat panel display

Kiosk

A CRT Monitor displays color pictures by using a combination of phosphors that emits different colored light namely Red, Green and Blue.

The two basic techniques for producing color displays with a CRT are:

1.Beam Penetration Method

2. Shadow Mask Method

CRT

In Beam Penetration Method, there are two layers of phosphorus usually Red And Green are coated inside of the CRT Screen and the displayed color depends on how far the electron beam penetrates into phosphor layer

A Shadow mask CRT has the phosphorus color dots at each pixel position. One phosphor dot emits a RED light, another emits GREEN light and third emits a BLUE light.

The term Flat Panel Display refers to class of display devices that have reduced volume, weight and power requirement as compared to a CRT.

Flat panel display is divided into two parts:

1. Emissive Display

• Plasma Panel and LED

2. Non-Emissive Display

• LCD

Plasma is a state of matter containing no. of eclectically charged particles. In plasma with an electrical current passing through it, -ve charged particles rush toward +ve charged area of plasma and +ve charge particles are rush towards the –ve charge area. In this mad rush particle collide with each other and light is produced.

LCD consume less power than LED because they work on the principle of blocking light rather than emitting it. LCD address each pixel individually, they can create sharper text CRTs

Modern electronics relies heavily upon LED light bulbs. The simplicity and long life of the LED make its use for various technological applications.

A kiosk is a small physical structure (often including a computer and a display screen) that displays information for people walking by.