Colour CRT Monitors

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 1) The normal CRT that we have seen up till now generate Images of single color due to limitation of phosphore coating i.e we saw in CRT Introduction part.

2) Phosphore are coated on screen so that when electrons strike on screen it illuminate light.

3) There are Two basic technique used for producing color on CRT are:

• Beam penetration technique.

• Shadow Mask technique.

Now we will see Beam penetration technique.

A) Beam penetration technique

1) Beam penetration technique is used with Random/Vector display where CRT is coated with 2 layers of phosphore, usually RED and GREEN.


2) Outer layer is RED and Inner layer is GREEN phosphore.

3) Color depends on how far the electron beam penetrates into phosphore layer. Penetrates means strike or enter.

4) Low electrons beam speed strike only RED phosphore those produces RED trace i.e RED color on the screen.

5) High electron beam speed penetrates into GREEN phosphore and produces GREEN trace on screen.

6) Medium electron beam speed produces color combination of ORANGE and YELLOW out of RED and GREEN phosphore coated screen.

7) So in Beam penetration technique we have total 4 combination of colours available.

8) What are the merits: Inexpensive

9) Demerit: -

• Only 4 colors are available

• Quality not good as compare to Shadow Mask technique.


*You can leave a comment if you have doubt in it.


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