Capacitive Interface

The Technology at glance

The user interfaces made of glass are capacitive keyboards. The sensors and the evaluation electronics are provided on a printed circuit board. The position of the sensors represents the position of the keys or the key pads respectively. In order to achieve a particular layout of the key pads a new printed circuit board design is required respectively.

In principle, a fitted circuit board on the basis of capacitive sensors already represents the technical perfection of this type of data input. The finger which effects the operation approaches the electrical field above the sensor until a signal, which is released by capacity variations is emitted towards the controller. The signal processing is effected as with a traditional keyboard.

For the realisation of suitable user interfaces, capacitive keyboards dispose of a high level of creative potential. Thus the electrical field of a capacitor penetrates the different materials with a various levels of thickness. Glass, plastic or other non-conductive materials are possible. Behind these materials, the printed circuit board of the capacitive keyboards can be fixed. In such case the graphical design of the user interface is restricted by the position of the sensors on the lower surface only. The design of opaque materials such as wood can be effected directly on the surface whereas in case of glass keyboards, a graphically designed decorative sheet is inserted between the glass and the printed circuit board. However, engraving of a glass pane, which is opaque towards the printed circuit board, is possible as well. 

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