An electrostatic encoder (40) detects the rotation angle of a rotor (42) with great accuracy based on the change in the capacitance between electrodes arranged on a stator (41) and the rotor (42). Detection electrodes (44a to 44d) and transmission electrodes (45a to 45d) are arranged circumferentially and alternately on the stator (41). Detection signals (phase A, phase B) amplitude-modulated based on the rotation of the rotor (42) and having a mutual phase difference of 90 degrees are output from adjacent ones of the detection electrodes. Modulated signals (V1, V2) are generated by demodulating the detection signals having a mutual phase difference of 90 degrees. Applying resolver-digital (RD) conversion processing to the modulated signals allows obtaining the rotation angle of the rotor.

A device for sensing a rotational position of a rotatable element for a household appliance includes: a stator having a plurality of capacitive sensor surfaces spaced apart from one another in a plane of extension of the stator; and a rotor rotatably positionable or disposed relative to the stator and having an electrically conductive section and a dielectric non-conductive section, the conductive section being larger in area than the non-conductive section, the rotor being disposed opposite the plane of extension of the stator in a rotatable condition relative to the stator, and the rotor being couplable or coupled to the rotatable element.

A capacitance sensation unit of plane position measurement device for performing measurement with submicron definition is able to measure both two-dimensional position and rotational angle relative to a plane object. The main application of the capacitance sensation unit is exemplified with the position measurement of the mover of a flat motor. The capacitance sensation unit is able to measure the position and rotational angle of the mover relative to the surface of a stator in the form of a flat plate.

A capacitance type rotation angle detection stage light includes a pivoting member and a supporting member for supporting the pivoting member. A reflecting grating is attached on the pivoting member, and the reflecting grating rotates along with the pivoting member. A signal grating is attached on the supporting member. The signal grating and the reflecting grating are arranged oppositely. The signal grating comprises capacitance emitting pieces, a capacitance receiving piece and shielding pieces. The reflecting grating comprises capacitance reflecting pieces that reflect signals sent from the capacitance emitting pieces to the capacitance receiving piece. Periodic excitation signals applied to the capacitance emitting pieces finally form a composite signal on the capacitance receiving piece through coupling of two pairs of capacitors that the capacitance emitting pieces and the capacitance reflecting pieces, and the capacitance reflecting pieces and the capacitance receiving piece.

Disclosed is an alternating electric field based plane 2D time-grating displacement sensor which includes two parts: the base of fixed ruler and the base of moving ruler, and the two parts are installed in parallel. The base of fixed ruler is arranged with square excitation electrodes that are respectively staggered coded along axis X and Y, and the base of moving ruler is arranged with induction electrodes arranged adjacently along X-axis and Y-axis, and the four induction groups respectively output four traveling wave signals through electric field coupling, and summation of adjacent output signals with an adder can simultaneously decouple two traveling wave signals with opposite phases and only containing X-axis displacement and two traveling wave signals with opposite phases and only containing Y-axis displacement; two traveling wave signals in either direction are differenced by a subtractor to eliminate common mode interference.

A device for determining an angle of rotation and/or a torque of a rotating part, having at least one angle detector for detecting an angular position of the rotating part relative to a reference position and at least one indexer for indexing at a 360° rotation of the rotating part relative to the reference position, the angle detector having a rotor connected in a non-rotatable manner to the rotating part with a base body for attachment to the rotating part and a plurality of vanes extending radially outwardly from the base body. At least one of the vanes of the rotor have a marker detectable by means of the indexer.

Disclosed is an alternating electric field based plane 2D time-grating displacement sensor which includes two parts: the base of fixed ruler and the base of moving ruler, and the two parts are installed in parallel. The base of fixed ruler is arranged with square excitation electrodes that are respectively staggered coded along axis X and Y, and the base of moving ruler is arranged with induction electrodes arranged adjacently along X-axis and Y-axis, and the four induction groups respectively output four traveling wave signals through electric field coupling, and summation of adjacent output signals with an adder can simultaneously decouple two traveling wave signals with opposite phases and only containing X-axis displacement and two traveling wave signals with opposite phases and only containing Y-axis displacement; two traveling wave signals in either direction are differenced by a subtractor to eliminate common mode interference.

An apparatus is provided and includes a rotary encoder that comprises a stator, a rotor, and a controller. The stator has an opening adapted to surround a first portion of a rotatable shaft, a transmit region, and a receive region. The rotor has an opening adapted to surround a second portion of the rotatable shaft, an annular conductive region, and at least one conductor electrically coupled with the annular conductive region. The controller has an input coupled to the receive region and has an output coupled to the transmit region. The controller is configured to transmit a first signal on the output of the controller and to the transmit region of the stator, receive a second signal on the input of the controller and from the receive region of the stator, and determine, based on the second signal, a proximity of the at least one conductor to the receive region.

A rotary encoder includes an electret unit, an electrostatic field sensor, and a controller. The electret unit generates an electrostatic field. The electrostatic field sensor is disposed proximate to the electret unit to sense a modulation of the electrostatic field that varies with rotation of one or more rotary components of the rotary encoder about a rotation axis of the rotary encoder. The controller is electrically coupled to the electrostatic field sensor to track activations of the electrostatic field sensor as the one or more rotary components rotate. The controller is configured to digitally encode a rotational position of the one or more rotary components based upon the activations.

A monitoring device for monitoring a screw joint of an object includes a base plate to be attached to the object and a top plate to be attached to one part of the screw joint, wherein the base plate and the top plate are positioned parallel to and on top of each other and wherein both plates each includes at least one electrode that capacitively interact with each other. The monitoring device is characterized in that the electrodes are shaped and positioned such that at least one electrode of one of the plates interacts with at least two different electrodes of the other one of the plates depending on the rotational position of the plates relative to each other. A monitoring arrangement having at least one monitoring device of this kind and a monitoring method are also provided.