Capacitive input device

摘要

An input device comprises a support plate and a cover plate. The cover plate has an upper surface facing away from the support plate and a lower surface facing towards the support plate, and includes a capacitive sensing arrangement associated with an input zone for capacitively detecting position and/or movement of a user's finger or stylus. One or more spacers arranged at the periphery of the input zone mount the cover plate on the support plate in such a way that the cover plate spans over the support plate in the input zone. The cover plate is designed with a rigidity such that a user may depress it towards the support plate in the input zone. The input device comprises a pressure-responsive switch associated with the cover plate and the support plate. The pressure-responsive switch includes at least one first electric circuit element arranged on the lower surface of the cover plate and at least one second electric circuit element arranged on the support plate in facing relationship with the at least one first electric circuit element in such a way that the at least one first electric circuit element and the at least one second electric circuit element can be brought into contact when the cover plate is depressed towards the support plate. The rigidity of the cover plate is such that, with increasing force acting on the first surface in direction of the support plate, a physical contact zone develops initially at a defined central point of the input zone and then gradually extends towards the periphery of the input zone and the at least one first electric circuit element and the at least one second electric circuit element of the pressure-responsive switch are arranged in such a way that an electrical contact is only established if the physical contact zone exceeds a predefined radius around the central point of the input zone.