2. SYLLABUS
• 5.11 Electronic Displays - L2
• Principles of operation of common types of
displays used in modern aircraft, including
– Cathode Ray Tubes
– Light Emitting Diodes
– Liquid Crystal Display.
4. CONTROLLING THE DEFLECTION
• There are two separate ways to control the
deflection:
– Electromagnetic deflection- magnetic principle
– Electrostatic deflection – depend on charges.
• Electromagnetic Deflection (Remember i=current)
8. • A color TV screen differs
Color TV Screen from a black-and-white
screen in three ways:
• Three electron beams (Red,
Green, Blue)that move
simultaneously across the screen.
• The screen is coated with red,
green and blue phosphors
arranged in dots or stripes.
• On the inside of the tube, very
close to the phosphor coating,
there is a thin metal screen called
a shadow mask. This mask is
perforated with very small holes
that are aligned with the
phosphor dots (or stripes) on the
screen.
• .
9. RASTER/STROKE SCANNING
Honeywell GREEN
YELLOW
STROKE
ATT 2 GS
SCANNING IS RASTER
USED FOR SCANNING RANGE
ALL OTHER AOA DATA
20 20
DISPLAYED (BLUE)
F
DATA
10 10
G 40
MODE
10 10 30
(BLUE)
S
CMD 20 20 I
M .99 20
200 DH DH 140 RA WX
RED
10
• Raster Scanning for Attitude • Raster Scanning - weather
Sphere return
• Stroke Scan for reminder • Stroke for texts, range,
10. LED DISPLAY
• PN diode
• Doping modify the color,
oxygen, nitrogen are used
• 7 bar display for numbers.
• Segment type display with
diffuser plate or plastic
deflector to increase the
size
P134
11. LED DISPLAY
Tapes and Pointers Dot Matrix Display
• LED's are also used to • LED's are normally arranged
replace the pointers or in a 9 X 5 matrix or a 4 X 7
tapes on circular scale or matrix.
vertical scale displays. • requires special driver
• individual diodes are circuits.
arranged in groups to form • more common in fields
the illuminated bars. outside aviation, with
• example is the TCAS displays being produced
Electronic Vertical Speed using light bulbs, metal
Indicator ‘Fly-From’ and discs and electromagnetic
‘Fly-To’ indications. devices.
12. LCD – LIQUID CRYSTAL DISPLAY
• Operating Principle
– The liquid crystal is enclosed between two set of
polarizes glass (p137) .
– In normal situation, the light can pass, but when
current is passed, the molecules of the crystal
changes its alignment and control the light.
– Color is obtained by color filter on top of the LCD.
13. PASSIVE AND ACTIVE MATRIX
• Passive Matrix
– Relies on grids of vertical / horizontal conductors
– Scanning current through the horizontal
conductors.
– pixel is off controlled by vertical conductors.
• Active matrix – TFT (Thin Film Transistors)
– Pixels are controlled by individual transistors.
– Expensive – 800x 600 resolution – 1.4 millions
transistors.
