Abstract: Various alternative embodiments of a multi-turn capacitive encoder device are disclosed. The device includes two members that are fixed relative to each other and that include respective capacitive electrodes that are capacitively coupled between the two members. The respective capacitive electrodes on one member act as transmitter electrodes and the respective capacitive electrodes on the other member act as receiver electrodes. One or more modulation members are relatively movable between the two fixed members to alter or modulate the capacitive coupling to correspond to the rotational or angular position of the modulation member(s). At least one of the modulation members is driven using a gear reduction system such that its angular or rotational position corresponds to a plurality of turns of the input shaft of the multi-turn encoder.

Abstract: A capacitive encoder includes a signal-balanced shield electrode configuration that does not require electrical ground connection or active sensing and control in order to maintain the shield electrode(s) at a sufficiently constant voltage during capacitive position measurements. The shield electrode configuration is positioned in a capacitive coupling gap between transmitter electrodes and receiver electrodes during operation. The shield electrode configuration is patterned in a manner that complements the layout of the transmitter electrodes, such that the shield electrode configuration inherently floats at a nominally constant electrical potential when coupled to the signals present on the transmitter electrodes.