5.11 - Electrostatic Displays Flashcards
What do the anodes in a CRT monitor do
First and second anodes concentrate the electrons into a beam and the third anode focuses the beam onto the screen
How is the beam projected in a CRT for large blocks of colour?
The electron beam is deflected onto the screen to give a raster
How is the beam projected in a CRT for symbols and text?
Generated by stroke scan. The beam follows the shape of the symbols
What happens as the temperature of the tube increases in a CRT?
Greater than 70’C - the raster is shut down and only the symbols remain.
Greater than 90’C - the whole monitor shuts down
What are the CRT advantages
Coloured Multifunctional Displays
What are the disadvantages of a CRT
- A long shape
- Heavy
- Warming up required
- High power consumption
- Thermal sensitivity
- Tend to burn in
Led advantages
- Small dimensions
- Robust
- Long lifetime
LED disadvantages
- Higher current consumption compared with LCD
- Limited Flexibility
What can a seven segment display be used for?
It can be used for numbers and a limited number of other symbols
What light does a LCD emit ?
LCDs don’t emit and light. They only control light
What are the LCD viewing modes
- Reflective
- Transmissive
- Transflective
What is reflected viewing mode
Reflective displays have an opaque rear polariser that includes a diffuser reflector, such as brushed aluminium. This display requires ambient light to be seen
What is Transmissive Viewing Mode?
Transmissive displays have a clear polariser on the front and the back. This display requires light coming from the back to be seen
What is transflective mode?
Transflective displays have a rear polariser that includes a translucent material which reflects part of the ambient light and transmitted backlighting
