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Touch panels
make it possible to enter data directly on the screen. Different
technologies open a multitude of potential applications:
Resistive
The resistive touch panel consists of a glass plate and a synthetic
film, which is attached to the glass plate by means of small
spacers. Both the glass plate and the above lying synthetic
film are coated with a conductive layer: when the synthetic
film is pressed onto the glass plate, the position of the closed
circuit can be located through the ohmic value of the x- and
y-axis.
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4-wire resistive touch panels have 4 conductors acting as sensors
to determine the x/y-coordinates.
5-wire resistive touch panels have 5 conductors to determine
the x/y-coordinates. The 5-wire technology is more robust than
the 4-wire technology.
Capacitive
The capacitive touch panel consist of a glass plate, which is
essentially coated with conducting layers. If these layers are
pressed on, the position of the interruption of the applied
electrical field can be located through sensors at the edge
of the touch panel.
The capacitive touch panel is particularly suitable for rough
environments (security against vandalism, temperature, etc.).
SAW (Surface Acoustic Wave)
A SAW touch panel consists of a glass plate, equipped with surface
acoustic wave transmitters and piezoelectric receivers. The
waves which are sent out travel along the glass surface to the
receivers. When a finger or an object touches the surface of
the glass, the propagation of the waves is interrupted. This
interruption can be located through the different receivers.
Infra-red
In a frame around the screen there are infra-red transmitters
on one side and receivers on the other. The transmitters and
receivers are positioned slightly above the screen surface.
Should a signal between transmitter and receiver be interrupted
(e.g. by a finger), the location can be defined exactly.
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Admatec AG
Fabrikstrasse 10
CH-4614 Hägendorf
Fon +41 62 896 00 48
Fax +41 62 896 25 80
info
 
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