Sindhu . M MCA ~3rd Yr

Table of Contents :

Color CRT Monitor Beam Penetration Method Shadow Mask Method Beam Penetration Vs Shadow Mask

A CRT monitor displays color

pictures by using a combination

of phosphors that emit different

color lights.

There are two techniques for

producing color displays on CRT.

They are :

1.Beam Penetration Method

2.Shadow Mask Method

Two layers of phosphor (red and green) are coated onto the inside of the CRT screen.

The displayed color depends on how far the electron beam penetrates into the layers.

The speed of electrons – beam acceleration voltage.

Slow Electrons Red colorFast Electrons Green colorIntermediate Speed Electrons Yellow and Orange colors

Quality of Picture is not so good and is inexpensive.

The color CRT has:Three color phosphor dots (red, green and blue) at each point on the screenThree electron guns, each controlling the display of red, green and blue light.Two Methods

Delta MethodIn-line Method

We obtain color variations by varying the intensity levels of the three electron beam.

Used in raster scan system (including color TV)

Designed as RGB monitors

Beam Penetration method Shadow Mask methodWhere Used Used with Random Scan

System  Used With Raster Scan

System 

Colors It can display Red , Green, Orange and Yellow.

It can display Millions of colors.

Color Dependen

cy

Less colors are available because the colors depends on

the speed of the electron beam.

Millions of colors are available because the

colors depends on the type of the ray.

Cost   Less Expensive    More Expensive 

Picture Quality

Quality of  picture is not so good i.e. Poor with Beam

Penetration Method.

Shadow Mask gives realism in picture with

shadow effect and millions of color.

Resolution It gives Low Resolution. It gives  High Resolution.