Touch sensors
Touch sensors are the basis for modern, interactive input devices, which are extremely
simple to use.
There are resistive and capacitive touch sensors, which differ in structure significantly:
- Resistive touch sensors use the pressure exerted by an object on an input medium to
create a connection between two transparent conductive layers. With this electrical
contact, the exact XY position of the contact point can be calculated on an area by
the scale in X-and Y-direction on the voltage gradient layers.
- Capacitive touch sensors already detect when an electrically conductive object is
approaching, but can be regulated in a way that a contact for switching is necessary.
Contrary to the resistive technology, it is not necessary to use pressure. Capacitive
touch sensors have an electrically charged surface, for example, grounded over the
human being, resulting in a low charge transport. This minimal current flow is
measurable at the corners of the surface, where the steady stress field is established.
This minimal current flow is clearly attributable to a specific point of contact by the
differences in strength at the respective corners.
Touch sensors are already widely used, especially for mobile phones and it is expected that
the market will strongly develop in the years to come. PolyIC's transparent conductive film
(PolyTC) offer an excellent basis to replace the now most commonly used ITO films.
Especially in the emerging multi-touch sensors, PolyTC films offer ideal conditions through
their individually structurable layouts that can be implemented directly in the production
without consuming additional steps. PolyTC can be used both for resistive and capacitive
touch sensors.
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