This ppt explains about the technological development behind the different aircraft display systems

1. Display Technology

2. Display Technology - HUD
Display surface is given by
 Monochrome CRT
 Line brightness more than 1,00,000 Cd/m2 and raster
luminance of 10, 000 Cd/m2
 High resolution in cursive and raster modes is
demanded
 Uses P1, P43 and P53 phosphor
 P1 spectrum  line broadening
 P43 & P53  spiked response

3.  Color display in HUD is possible by Penetron CRT
 Limited color range – two primary colors and shades
between
 Color HUD has limitations
 Loss of resolution and brightness
 Additional cost complexity
 Increased weight and volume

4. Display technology – HDD
Color HDD are based on Color CRTs
Situation Changes with the advent of color LCD
Color CRTs are of three major types
 Shadow Mask CRT
 Beam Index CRT
 Penetron CRT

5. Shadow Mask CRT
 Operate similar to domestic color TV
 Designed to withstand vibrations
 Has separate electron gun for each primary color
 Electron beams converge on a thin foil mask with
apertures synced with RGB Triad

7. Use of INVAR materials has increased
the ruggedness
Shadow Mask tube is simple
Works well in raster, cursive and mixed
modes

8. Beam Index CRT
 Has single electron gun
 Beam is scanned over vertical RGB stripes
 Phosphor is placed between each RGB stripe
 Emission from the phosphor detects the beam position
and the intensity is switched as needed
 Brightness is higher than shadow mask
 Color purity is lost if the spot size exceeds triad width

9. Limitations
Need for
 Complex drive electronics
 High bandwidth video amplifiers
 Cannot be operated at low luminance without loss
 Night operation limitations
Biggest advantage is its ruggedness

10. Penetron CRT
Relatively an old concept
Beam excites different layers of a composite
phosphor (arranged like onion skin layers)
Two phosphor layers are used – so the two
colored display and shades between them

11. Flat panel displays
Include the following technologies
 Light emitting diodes
Electro luminescent
Plasma
Vacuum fluorescent
Liquid crystal

12. lcd

13. LCD
 In night , this is used with electro luminescent
back light
 Good high contrast for high resolution, a thin
film transistor needs be used
 Called as active matrix LCD (AMLCD)

14. LCD CRT
 LCD shutters & CRT -> intermediate stage btw LCD and the
CRT
 LC devices are placed infront of a monochrome mixed
phosphor CRT
 Color information -> in the frames with the shutter switch
 High resolution of the monochrome CRT is retained at low
optical efficiency
 Video should be stored in frames (operation of the LC shutter
is two or three times faster than the normal video rate)

15. AMLCD
 Operate without the back light
 Fluorescent lamp
 Not flat panel
 Less deeper than the CRT
 Not a low power display
 Not cheap at the moment

16. LED
Data displays can be done
But limited to small areas
High power requirements
Good brightness and contrast but resolution is poor
Produced with red and green LEDs
Used in displays for warning, engine monitoring, helmet
mounted sights

18. Electro Luminescent
 Good viewing angle
 Pleasing display
 High drive voltage is required – expensive
drive circuits – effect on reliability
 High resolution is possible but colors are
limited (blue difficult)
 Used in control and display units for comms,
navigation and maintenance

19.  EL works by exciting atoms by
passing an electric current
through them, causing them to
emit photons
 GaAs layer

20. Plasma display
Gas discharge displays
High brightness products
Used in tactical terminals – 8inch square
display with 64 pixels per inch

21.  Xenon gas misture

22. Vacuum fluorescent
Limited in size – 8 inch diameter
Difficult to make
Needed brightness and color
No much development