Abstract: A capacitive motion encoder, for sensing the position of a moving object relative to a stationary object, includes at least one stationary element, coupled to the stationary object and a moving element, coupled to the moving object and in proximity to the stationary element. A field transmitter generates an electrostatic field, which is modulated by a change in capacitance between the stationary and moving elements responsive to relative motion of the elements. A conductive shield, is electrically decoupled from both the moving and the stationary objects, and encloses the moving and stationary elements so as to shield the elements from external electrical interference. Processing circuitry is coupled to sense the modulated electrostatic field and to determine responsive thereto a measure of the position of the moving object.

Abstract: A capacitive motion encoder, for sensing the position of a moving object relative to a stationary object, includes at least one stationary element, coupled to the stationary object and a moving element, coupled to the moving object and in proximity to the stationary element. A field transmitter generates an electrostatic field, which is modulated by a change in capacitance between the stationary and moving elements responsive to relative motion of the elements. A conductive shield, is electrically decoupled from both the moving and the stationary objects, and encloses the moving and stationary elements so as to shield the elements from external electrical interference. Processing circuitry is coupled to sense the modulated electrostatic field and to determine responsive thereto a measure of the position of the moving object.

Abstract: What is described here is a device for the transmission of electric signals between at least two units mobile relative to each other, such as a slip ring or a sliding path, respectively.

Abstract: A low-cost system for wireless, bi-directional transformation of electric signals over a capacitive interface between a host unit and a guest unit is provided. The system allows a high impedance in the circuitry of the guest unit to obtain a good signal transfer ability in conditions of poor dieelectric materials, poor conductivity in the contact pads and relatively large gaps between the contact pads. The capacitive interface comprises a respective first (A1; B1), second (A2; B2) and third (A3; B3) conductive area in the host and guest units (10,40). The first conductive area (A1) of the host unit is connected to a self-tuning frequency generating resonant circuit (16) in the host unit (10) for obtaining high gain of signals transmitted to the guest unit (40). The second and third conductive areas (A2, A3) of the host unit are connected to an impedance circuit (30) in the host unit for receiving signals from the guest unit.

Abstract: A non-contact measuring method and apparatus for producing a signal representative of a distance between facing surfaces of first and second parts, which are closely spaced apart such as the rotor and stator of an electric rotating machine. The method resides in positioning a sensor on the surface of the first part. The sensor includes first and second parallel, superimposed conductive plates electrically insulated from one another. The second plate is located in between the first plate and the surface of the first part. The first plate is fed with a high frequency signal through a resistance. A high impedance, low input capacity, unitary gain voltage amplifier is fed with the high frequency signal through the resistance. The second plate is fed with an output signal of the amplifier. The output signal of the amplifier is directly proportional to the distance between the two surfaces.

Abstract: A capacitive motion encoder, for sensing the position of a moving object relative to a stationary object, includes at least one stationary element, coupled to the stationary object and a moving element, coupled to the moving object and in proximity to the stationary element. A field transmitter generates an electrostatic field, which is modulated by a change in capacitance between the stationary and moving elements responsive to relative motion of the elements. A conductive shield, is electrically decoupled from both the moving and the stationary objects, and encloses the moving and stationary elements so as to shield the elements from external electrical interference. Processing circuitry is coupled to sense the modulated electrostatic field and to determine responsive thereto a measure of the position of the moving object.

Abstract: An improved data output retrieval communication method and apparatus for reading portable miniaturized temperature and related sensors by novel radio-frequency capactively coupled communication paths established at a common readout station to which the sensors are brought for such readout to a common computer or the like.

Abstract: An industrial process control transmitter has a capacitive sensor having at least three outputs each responsive in differing amounts to a process condition and to sensor hysteresis. An excitation circuit charges the sensor and pumps the charges to a sigma-delta capacitance-to-digital converter. The excitation circuit includes a charge amplifier coupling one of the sensor outputs to a summing node for summing with a charge on at least one other output. An auto-zeroing switch re-sets the charge amplifier on each cycle of operation of the charge amplifier.

Abstract: A capacitive motion encoder, for sensing the position of a moving object relative to a stationary object, includes at least one stationary element, coupled to the stationary object and a moving element, coupled to the moving object and in proximity to the stationary element. A field transmitter generates an electrostatic field, which is modulated by a change in capacitance between the stationary and moving elements responsive to relative motion of the elements. A conductive shield, is electrically decoupled from both the moving and the stationary objects, and encloses the moving and stationary elements so as to shield the elements from external electrical interference. Processing circuitry is coupled to sense the modulated electrostatic field and to determine responsive thereto a measure of the position of the moving object.

Abstract: A position sensor comprises a capacitive transducer and an inductor connected in series with the transducer. The transducer is a differential capacitor whose total admittance is essentially independent of changes in the sensed position. The total capacitance and inductance resonate at the fundamental frequency of a generator that provides a drive voltage and the resulting voltage across the sensor is thus substantially greater than the drive voltage. This increases the current through the transducer, and consequently increases the sensitivity of the sensor.

Abstract: The capacitive angular displacement transducer includes a first stator (2) comprising a plurality of electrically conductive; circular ring-shaped electrodes (51) which are electrically isolated from each other and have a predetermined sector angle, with a second stator (4) arranged parallel to the first stator comprising a receiving electrode (6), and with a rotor (3) mounted on a rotatable shaft (7) comprising at least one rotor blade (8a, 8b) in the form of circle sectors and located perpendicular to the shaft and the rotor blade being located parallel to and between the first and the second stators. The sum of the central angles of all transmitting electrodes is less than 2&pgr; (360°), preferably ranging from &pgr;/12 (30°) to 5&pgr;/6 (300°), and the central angle of each rotor blade is essentially equal to the sum of the central angles of n adjacent or neighboring transmitting electrodes.

Abstract: An electronic device (1), e.g. a mobile telephone having a front cover (6) and a capacitive proximity sensor, comprising: a first electrode (9; 27) and a second electrode (8; 21, 20), said first electrode having a large face (11, 12, 13; 29); and detector means connected to the first electrode (9, 27) and the second electrode (8, 21, 20) for detecting the capacitance of the first electrode relatively to the second electrode and for providing a control signal (Vprox) responsive to the capacitance. The large face (11, 12, 13; 29) of the first electrode is inclined relative to the front cover (6).

Abstract: In a method for capacitive object recognition in vehicles, two capacitive electrodes are charged with alternating voltage and the presence of an object is detected by the change in the capacitance in the capacitor. The two electrodes are charged sequentially and individually with alternating voltages. The alternating currents that result in the leads of the two electrodes are analyzed jointly.

Abstract: A capacitive sensing system for detecting the angular position of a rotatable member of a motor. The position detection system includes a cylindrical excitation pin attached to the housing of the motor and a tubular signal plate, having a plurality of sensing surfaces symmetrically arranged about the axis of rotation of the rotatable member, which surrounds the cylindrical excitation pin and, which is also attached to the motor housing. A lobed dielectric is attached to the rotatable member of the motor and inserted between the cylindrical excitation pin and the tubular signal plate. An electric circuit connected to the sensing surfaces of the tubular signal plate calculates the relative angular position of the rotatable member from the amount of energy detected at each of the sensing surfaces.

Abstract: A poppet valve moves up and down in a valve operating mechanism in an internal combustion engine. A cylindrical fixed electrode is fixed to a support plate on a cylinder head, and a cylindrical moving electrode is mounted to the lower surface of a valve spring retainer which is mounted to the poppet valve via a cotter. The fixed electrode is connected to a circuit which comprises a variable condenser and a resistance. The valve moves up and down during firing operation of the engine. Thus, variation in electrostatic capacity is detected by the two electrodes, transmitted to a circuit via a lead mounted to the fixed electrode, and converted to a voltage by the circuit, thereby detecting valve position exactly.

Abstract: A galvanometer is described which has increased capacitance and which is hardly affected by humidity while maintaining the advantages of low machining precision and being unaffected by temperature variations. A front bearing and a rear bearing are fixed to a front shaft and a rear shaft, respectively, of a rotor held in a coil of a stator. Only an outer race of the front bearing is slidably inserted without being fixed to a case and has a force applied in a rear shaft direction by springs. A butterfly-shaped common electrode, which is patterned with a conductive thin film, is mounted on the rear shaft through a hub, and a four-division electrode is opposed thereto with an extremely small air gap to the butterfly-shaped common electrode. The four-division electrode is mounted on a spacer, and the spacer is mounted on the case so as to provide the air gap of a desired dimension. The rear shaft, the hub, and the spacer are made of an identical material.

Abstract: A capacitive object detection system for a vehicle has first and second capacitive electrodes embedded in the vehicle seat. The two electrodes are excited by oppositely phased alternating voltages, which are adjusted by a controller such that the resulting alternating currents in their respective feed lines are substantially equal and oppositely phased. The presence, size and location of an adjacent object is then determined based on an analysis of the impedances of the first and second electrodes.

Abstract: A transmitter includes a pair of electrodes separated in space, and transmit circuitry for varying the voltage difference applied across the electrodes in order to vary the spatial gradient of the electric potential field generated by the transmitter in accordance with the data to be transmitted. The receiver includes a pair of electrodes separated in space and receive circuitry which detects these variations in the quasi-electrostatic potential field in order to receive the transmitted data. Thus the receive electronics unit includes a detector connected to said electrodes for producing a signal which varies as the spatial gradient of the electric potential field across the receive electrodes varies but which does not depend on changes in potential within any given electrode.

Abstract: An apparatus for capacitively determining a position of a counter wheel (1) in a wheel counter mechanism has fixed electrodes (3, 3′) at a distance from the counter wheel (1). Extending over the circumference of the counter wheel (1) are a sequence of measurement electrodes (12, 12′, 12″), and electrically nonconductive sections (13, 13′) arranged between said measurement electrodes. This means that it is possible to detect either a high or a low capacitance value, that is to say a binary value of either 0 or 1, for each position of the counter wheel and for each fixed electrode. According to the number of fixed electrodes for each counter wheel, these binary values can be combined to form a binary representation of any desired number characterizing the current position of the counter wheel (1).

Abstract: A poppet valve moves up and down in a valve operating mechanism in an internal combustion engine. A fixed electrode is supported on a cylinder head, and a moving electrode is carried by the poppet valve. The fixed electrode is connected to a circuit, which together comprises a variable condenser and a resistance. The valve moves up and down during firing operation of the engine. Variation in electrostatic capacitance is detected by means of the two electrodes, transmitted to the circuit via a lead and a ground connection, and converted to a voltage by the circuit, thereby enabling detecting valve position more exactly.

Abstract: From the time of power on, an output of a variable frequency generating circuit is kept matching with the resonance frequency of a resonance circuit. When an object of detection comes into contact or to the vicinity of a detection electrode and the resonance frequency of resonance circuit changes, a phase deviation is generated from the output of the variable frequency generating circuit. The deviation is detected by a phase comparing circuit, and a control circuit changes a control voltage so that the oscillation frequency of variable frequency generating circuit is changed to attain phase matching. This change is detected by a detection circuit, and presence/absence of the object is detected.

Abstract: A displacement sensor comprises a first scale (11) and a second scale (12) that are arranged opposing to each other and relatively movable in the measurement axis direction. The first scale (11) includes a transmitting electrode array (13) and a receiving electrode (14). The transmitting electrode array (13) consists of a plurality of transmitting electrode units arranged in a basic period (W1) in the measurement axis direction. Each transmitting electrode unit consists of n transmitting electrodes that are arranged in the measurement axis direction and receive respective phase signals of n-phase transmission signals. The receiving electrode (14) adjoins the transmitting electrode array (13) in the direction perpendicular to the displacement direction. The receiving electrode (14) has a width equal to the basic period (W1) and smaller than a width of the transmitting electrode array (13).

Abstract: Capacitive coupling is used to transmit data and power through a user's body. In one implementation, a transmitter carried by the user transmits power and data to a receiver, which is also carried on the user's body. The signal that the transmitter applies to the user's body not only contains a data component, but also powers the receiver and enables it to detect and decode the data. In other implementations, the transmitter or the receiver is physically displaced from the user's body (although both receiver and transmitter are coupled to environmental ground), and data and power are transmitted when the transmitter and receiver become sufficiently proximate—via the user's body—to permit capacitive coupling. The disclosed approach is amenable to a wide variety of applications, ranging from “interbody” exchange of digital information between individuals through physical contact (e.g., a handshake) to “intrabody” data transfer (e.g.

Abstract: The present invention provides a capacitive resolver (100). The capacitive resolver (100) includes a charge plate (102), a sensing plate (106), and an interrupter plate (400) positioned between the charge plate (102) and the sensing plate (106). The front surface of the sensing plate (500) has a sinusoidal pattern (502). The back surface of the sensing plate (600) includes charge detectors (602), charge collectors (608), and rectifiers (618). The capacitive resolver (100) also includes a signal generator (110) which is electrically connected to the charge plate (102) and a signal analyzer which is electrically connected to the sensing plate (106). The capacitive resolver (100) may additionally include a non-conductive support (112).