How is the electric wiring of a foil keyboard realised?

The electric wiring of foil keyboards can be selected arbitrarily taking into account the design rules. The through-connexion used to connect the front and rear conductors known from the circuit board disentanglement would prove very time-consuming on the thin, flexible polyester raw material.

Therefore it is now common practice to realise several levels by means of imprinted silver conductors and isolation prints with overlying printed bridge circuits.

To be able to realise a disentanglement suitable for production, this is carried out by our development department. Therefore it is absolutely sufficient if the customer defines the desired wiring in the form of an array/connexion table.

It has especially proven of value to write the evaluation software after the effected disentanglement.

There are two basic types of constructions:

• Shared control line:
  The advantage consists in the comparatively simple disentanglement, production and evaluation, the disadvantages are that there is more space required for the conductors and that there is a large number of wrap connexions.

• Matrix wiring:
  The advantage of this wiring option is that less space is required for the conductors and that less wrap connexions are required.
  The disadvantages consist in the somewhat more costly disentanglement, production (bridge circuit) and evaluation (keyboard controller). 

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