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REAR-MOUNT OPEN-FRAME LCDS |
REAR-MOUNT OPEN-FRAME LCDS WITH TOUCH |
IR TOUCHSCREENS
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Rear-mount Open-frame LCDs with Touchscreen Technology
I&E offers IR, SAW and Capacitive touchscreens using an open-frame design,
particularly suitable for OEM applications. The rear-mount open-frame design
is feasible in that it can be easily mechanically designed in, ease of field
maintenance, suitable for harsh environment, depending upon the
touch technology which can be easily selected below.
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LCD Models Selection Table - No
Touch |
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Video Interface(s) |
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I&E MODEL # |
Size |
Brightness (NITs) |
VGA |
S-Video |
DVI-D |
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IE-301G
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15" |
380 |
n |
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IE-302GS
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17" |
700 |
n |
n |
n |
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IR (Infrared) Technology Overview
An infrared touch screen surrounds the face of the display with a
bezel of light emitting-diodes (LEDs) and diametrically opposing
phototransistor detectors. The controller circuitry directs a sequence
of pulses to the LED's, scanning the screen with an invisible lattice of
infrared light beams just in front of the surface. The controller
circuitry then detects input at the location where the light beams
become obstructed by any solid object.
SAW (Surface Acoustic Wave) Technology Overview
Surface wave is based on transmitting acoustic waves across the surface
of a glass overlay placed over the display surface. A transducer mounted
on the edge of the glass emits acoustic waves which travel on the
surface of the glass overlay. A second transducer on the opposite side
of the glass receives the acoustic waves. An acoustically dense object
touching the glass surface blocks the traveling waves. In addition to the X
and Y coordinates, SAW technology can also provide Z axis (depth)
information. The harder the user presses against the screen, the more
energy the finger will absorb, and the greater will be the dip in
signal strength. The signal strength is then measured by the controller
to provide the Z axis information.
Capacitive Technology Overview
Capacitive touchscreens comprise an all glass
sensor coated with a thin, insulated, and transparent coating, providing
a conductive surface from which the capacitance of the human body can be
picked up, creating an X/Y coordinate. Capacitive screens will not work
with non-conductive objects so do not pick up signals from gloved hands,
styli etc. Periodic calibration is required because of drifting.
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Touchscreen Technology Comparison Table |
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Infrared |
SAW |
Capacitive |
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Transparency |
99% |
92%
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85% |
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Color distortion |
No |
No |
Yes |
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Resolution |
4096 x 4096 |
4096 x 4096 |
1024 x 1024 |
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Coordinate system |
2D |
3D
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2D,
no origin |
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Drifting |
No |
No |
Yes |
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Vandal resistance |
Excellent |
Good |
Good |
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Response speed |
10-35ms |
10ms |
15-24ms |
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Electromagnetic interference |
No |
No |
Yes |
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Noise interference |
No |
Yes |
No |
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Dust and water proof |
Excellent |
Not
good |
Good |
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Handwriting |
Yes, smooth |
Yes |
Yes |
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Touch objects |
Any
object |
Bare finger or conductive stylus |
Bare finger or conductive stylus |
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Maintenance |
None |
Need regular calibration |
Need regular calibration |
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