Method and device for accurate capacitive measured value acquisition

摘要

A device and a method for the capacitive detection of an object which is preferably arranged behind a flat article that is transparent to electromagnetic radiation or a wall, including a sensor incorporating sensor electrodes for the detection of the object, preferably for the detection of relative movements between the sensor and the flat article or a finger, where a control circuit serves for the control of the sensor electrodes and for the evaluation of the output signals of the sensor, and, due to the fact that the sensor comprises at least one sensor electrode which is surrounded by at least one further electrode, the surrounding further electrode is connected to the sensor electrode by the control circuit in such a manner that, in the event of a change of the potential of the sensor electrode, the potential of the surrounding further electrode is regulated in the opposite sense to the sensor electrode in such a way that the sensor electrode remains at a pre-determined or pre-definable potential, such that there is produced a capacitive sensor which does not react to tilting or small changes in the spacing from the surface.

主权项

1. A device for the capacitive detection of an object such as a post, a line or a finger which is arranged behind a flat article that is transparent to electromagnetic radiation, comprising
a sensor which comprises at least one sensor electrode for at least one of the detection of the object or for the detection of relative movements between the sensor and at least one of the flat article or the finger, a control circuit for controlling the at least one sensor electrode and for evaluating the output signals of the sensor, wherein the at least one sensor electrode surrounded by at least one surrounding further electrode, wherein the surrounding further electrode is connected to the at least one sensor electrode by the control circuit whereby in the event of a change in a potential of the at least one sensor electrode, a potential of the surrounding further electrode is regulated by a closed-loop control in the opposite sense to the at least one sensor electrode whereby the at least one sensor electrode remains at a pre-determined or a pre-definable potential.