Elucidate Beam penetration method

Question

Elucidate Beam penetration method?

Answer 1

In random scan display systems this type of technique is used. 2 layers of phosphor i.e. red and green are coated on inside of CRT screen; the electron beam penetrates into the phosphors layers after the displayed colors. A slow electron beam stimulates only on the outer red layer. Electron beam penetrates trough red layer very fast and therefore it excites the green layer. An average electron beam provides the combination of red and green color i.e. yellow and orange. This technique only provides 4 colors.