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Name: Joe
Status: Student
Grade: 6-8
Location: IL
Country: United States
Date: Summer 2009

How do screens such as TV's, liquid crystals, plasmas, and computer screens light up?


In answer to the 4 examples you asked about:

1. Vacuum Tube TVs: on the inside of the screen, there is an array of microscopic phosphor dots that emit light when they are hit by the three electron guns in the picture tube. More information about how a picture tube works can be found here:

2. Liquid Crystal (LCD) screens: These have a backlight (a light source located behind the LCD) that illuminates the screen from behind, through an LCD color filter.

3. Plasma Screens generate their own light as a result of a high voltage discharge. More information can be found here:

4. Computer screens use one of the three technologies explained above.


Bob Wilson

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