Industrial Electronic Engineers, Inc.
SIZE
A
CODE IDENT NO.
05464
S03875–21–0214
Van Nuys, California
SCALE N/A
REV A
SHEET 23
8.0
FIBER OPTIC BACKLIGHT
8.1
FO Backlight Description
The module contains a light emitting flat panel constructed of plastic optical fibers which convey the light from a
separately located light source. The panel is heat free, has indefinitely long life and has good brightness
uniformity. The optical fibers are gathered into a bundle at the end of the flat panel and are routed to the light
source.
The separately located light source is affixed to a bracket that mounts behind the display module using two of
the module mounting holes (see the outline drawing, Figure 18). If the increased module depth is not
acceptable, light source can be relocated elsewhere by the user within an approximate 2.5 inch radius (length
of the fiber bundle) from the end of the display module. The standard light source is a halogen 5.0 Volt, 4.85
Watt lamp with 8.0 inch leads terminated by a connector to be connected by the user.
Care should be exercised in the physical location of the light source since halogen lamps operate in excess of
250 C.
Because the attenuation of the LCD cell, only 10% of the backlight luminance is emitted from the display. Thus
to provide a brightly lit display, the original light source must be 10 times brighter.
8.2
Lamp Characteristics
The standard light source is a 4.85 Watt, 5.0 Volt halogen lamp. Figure 17 below shows the standard light
source and two alternates which use less power. They may be satisfactory for a display in low to no ambient
light and are available by special order.
Lamp
Power
Rated
Voltage
Relative
Brightness
Rated
Life (R
L
)
Lamp
Type
* 4.5 Watts
5.0 Volts
1.0
15k Hours
Halogen
2.5 Watts
5.0 Volts
0.6
5k Hours
Gas
1.5 Watts
12.0 Volts
0.1
15k Hours
Incandescent
Figure 17
Typical Lamp Characteristics
These sources all include a reflector as part of the lamp, which focuses the light toward the polished end of the
fiber bundle.
Rated life is expressed for operation at design voltage with alternating currents under laboratory test conditions.
Actual life (L
A
) is very sensitive to applied voltage (V
A
) as expressed by the following equation where V
R
is the
rated design voltage.
L
A
= (R
L
) (V
R
/V
A
)
12
The lamp may be powered by either AC or DC voltage. The 8.0” lamp leads are terminated in a Molex
connector P/N 50–57–9402. This mates with numerous Molex headers including the following:
70553–0106, PWB Mount
70107–0036, Panel Mount
70107–0001, Wire–To–Wire
8.3
Standard Operation
