Abstract: A relative-dielectric-constant measuring apparatus according to the present invention includes an ellipsometer and a capacitance measuring part. The ellipsometer allows non-contact measurements of the film thickness and optical constants of an insulation film formed on the upper surface of a wafer. The capacitance measuring part, on the other hand, allows non-contact measurements of the gap between the insulation film and an electrode and accumulation capacitance. The relative-dielectric-constant measuring apparatus can calculate the relative dielectric constant of the insulation film based on the measured film thickness, gap, and accumulation capacitance. Thus, the relative dielectric constant of the insulation film can be determined without contact and with high precision.

Abstract: The invention relates to a method and a device for determining the parameters of a fluctuating flow of a fluid in a pipe, wherein at least three electrodes that are placed at a distance from one another in the direction of flow are provided in the periphery of the flow, wherein alternating voltage signals are fed to a first upstream transmission electrode arrangement and to a second downstream transmission electrode arrangement and the receiving signals generated by the displacement current are detected in a receiving electrode arrangement located between the transmission electrodes and subjected to a time-discrete cross-correlation. The throughput times of the fluctuations detected by the electrodes are determined on the basis of the results.

Abstract: A method for determining a property of an insulating film is provided. The method may include obtaining a charge density measurement of the film, a surface voltage potential of the film relative to a bulk voltage potential of the substrate, and a rate of voltage decay of the film. The method may also include determining the property of the film using the charge density, the surface voltage potential, and the rate of voltage decay. A method for determining a thickness of an insulating film is provided. The method may include depositing a charge on the film, measuring a surface voltage potential of the film relative to a bulk voltage potential of the substrate, and measuring a rate of voltage decay of the film. The method may also include determining a thickness of the film using the rate of voltage decay and a theoretical model relating to current leakage and film thickness.

Abstract: Techniques for imaging a search region to detect a dielectric target include placing multiple electrodes outside the search region. At least two electrodes are activated independently of each other. Emitter circuits are connected to corresponding emitter electrodes. Each emitter circuit is configured for using its emitter electrode to produce an electric field with wavelength longer than about one hundred meters. Receiver circuits are connected to corresponding receiver electrodes. Each receiver circuit is configured for using its receiver electrode to measure a property of an electric field produced, at least in part, by an emitter electrode. A processor determines a property of a dielectric target inside the search region based on measurements from the receiver circuits using a subset of the emitter circuits. Among other uses, these techniques allow humans to be detected inside building-size regions, even when hidden by visually opaque blocking material of small dielectric constant.

Abstract: An unknown object shape is computed using repeated iterations of electrostatic calculations on a predetermined shaped object and sensed electrostatic measurements. The predetermined object shape is morphed toward the unknown object shape at each iteration until the object shape is determined. The morphing of the shape is based on calculating the zero contour of the electrostatic potential, which potential depends on a charge distribution applied to the predetermined shape.

Abstract: A method of measuring flat-band status capacitance of a gate oxide in a MOS transistor device is disclosed. According to the method of measuring flat-band status capacitance of gate oxide in MOS transistor device, flat-band status capacitance of gate oxide in MOS transistor device can be automatically measured and immediately analyzed by using a characteristics measuring system that changes in accordance with a gate voltage.

Abstract: Security scanning devices based on electrical tomography, including tomography systems based on the measurement of capacitance (ECT) and electromagnetic tomography (EMT), in combination with knowledge-based image analysis and understanding. Each device includes a sensing head or transducer, sensing electronics, image reconstruction and image analysis microprocessor (either microcontroller, DSP, laptop or desktop PC), a display unit and accompanying software for identifying dangerous materials and items. The security scanning devices enable enhancement of image resolution with ECT and EMT. More sensors, more sensitive circuits and flexible/optimal measurement protocols may be employed for obtaining more independent measurements and enable implementation of data fusion to combine the complementary sensitivity of ECT and EMT to different material properties, while providing architecture to implement image knowledge bases, which may characterize objects, whose image attributes are acquired from multiple sensors.

Abstract: The present invention provides a sensor and apparatus for measuring flow electric potential for evaluation of a degree of electrodeposition of paint applied to the body or chassis of a vehicle. The sensor includes a base plate part, a dielectric polymer member, a positive (+) electrode terminal and a negative (?) electrode terminal, and an insulation part. The base plate part is mounted on the outer and inner body or chassis of a vehicle, and is electrically connected to ground. The dielectric polymer member is patterned and formed on the base plate part. The positive (+) electrode terminal is connected to the dielectric polymer member and is configured to have a positive (+) polarity. The negative (?) electrode terminal is connected to the base plate part and is configured to have a negative (?) polarity. The insulation part is formed to insulate the positive (+) and negative (?) electrode terminals from each other.

Abstract: A capacitance sensor system and method includes a capacitive sensor as an array of sensor electrodes near the surface of the integrated circuit and charge pump circuits for measuring the capacitance at each sensor electrode. Shield electrodes and unused sense electrodes are used for background capacitance cancellation at each array location. The shield electrodes are switched between the circuit supply potentials in a manner synchronous to the capacitance sensing at the sense electrodes. The improved background capacitance cancellation allows all circuitry to be located outside the sensor array. The capacitance data is used to determine the positions of fingerprint artifacts and other fingerprint features.

Abstract: A method for non-contact measurement of a displacement between a surface and a capacitive sensor comprised of at least two superimposed conductive plates electrically insulated one from the other and a sensor circuit coupled to the plates including: positioning the capacitive sensor proximate to the surface such that the displacement is a distance of a gap between the surface and one of the plates; applying a high frequency signal to the plates; applying the high frequency signal and a sensor plate to control a voltage gain of an amplifier in the circuit, where the capacitance on the sensor is indicative of the displacement between the sensor and surface; differentiating an output of the amplifier and the high frequency signal, and determining a value of the displacement based on the difference between the output of the amplifier and the high frequency signal.

Abstract: The present invention relates to a fingerprints detection apparatus by a capacitance detection method. The fingerprints detection apparatus of the present invention includes a sensor portion in which an insulating protection film is formed so as to cover detection electrodes arranged like an array, and the detection electrodes and the wiring beneath the detection electrodes are formed of a refractory metal or a compound of the refractory metal. This structure heightens the Vickers hardness of the detection electrodes and the wiring. This makes it possible to provide a highly reliable fingerprints detection apparatus in which a tolerance to cracks of the insulating protection film in the sensor portion is improved.

Abstract: A proximity sensor module includes a housing; and a proximity sensor disposed in the housing, wherein the proximity sensor comprises a sensor plate configured to contact inside of the housing such that substantially no gap exists between the sensor plate and the housing. The housing may be a substantially explosion-proof housing. The housing may include two members coupled by a thread engagement, wherein a sensor plate of the proximity sensor is placed off-center with respect to an axis of rotation for the thread engagement.

Abstract: A method of calibrating a gauge in particular for the measurement of film thickness, uses a calibration variable to compensate for short term changes in probe tip condition, instead of a constant value. A calibration constant is based only on the dielectric constant for a coating such as lacquer, and is independent of the probe tip variable.

Abstract: A method of measuring electrical characteristics of a gate dielectric. The gate dielectric is local annealed by directing a highly localized energy source at the measurement area, such that the measurement area is brought to an annealing temperature while surrounding structures are not significantly heated. While heating the measurement area, a flow of a gas containing a percentage of hydrogen, deuterium, or water vapor at a flow rate is directed to the measurement area. A charge is inducted on the measurement area and the electrical characteristics of the gate dielectric are measured using non contact electrical probing.

Abstract: Aspects of the invention provide a superior electrostatic capacitance detecting device. The electrostatic capacitance detection device can include M number of row lines, N number of column lines, and electrostatic capacitance detecting devices formed at intersections of these lines. The electrostatic capacitance detecting element can include a signal detection element, a signal amplifying element, a column selecting element, and a row selecting element, and the signal detection element can include a capacitance detecting electrode, a capacitance detecting dielectric layer, and a reference capacitor, and one electrode of the reference capacitor connects to a column line.

Abstract: A non intrusive method and system for the dynamic measurement of a distance, or the variations over time thereof, constituting the thickness, or the variations thereof, of a thin compressible dielectric material located between one or several other closely spaced solid dielectric layers of constant thickness and a conductive or semi-conductive surface. This is achieved by positioning a capacitive sensor on the external layer of the dielectric material, the sensor being composed of two parallel plates electrically insulated from one another, feeding the first plate with a high frequency signal, measuring the voltage and current value over time generated by the high frequency signal between the plate of the sensor which is closest to the surface of the outer layer of dielectric material, and deducting the above distance or variations thereof.

Abstract: A computer system (10) includes a keyboard (11), a first pair of position-sensing electrodes (18.1 and 18.2), a second pair of position-sensing electrodes (20.1 and 20.2), a signal injection electrode (22) and an oscillator (27). The oscillator injects a signal via the electrode (22) and the operators left hand L, creating a field around the operator's right hand R. The position electrodes are arranged underneath the keyboard and sense the strenght of the field enabling the position of the operator's right hand R in an X-Y plane above the keyboard to be determined. Each position-sensing electrode is coupled to a difference amplifier (28 and 30) via a pair of buffer amplifiers (40.1, 40.2, 30.1, 30.2). The amplification factor of the buffer amplifiers can be varied so as to scale the field strength values sensed by the electrodes, thereby permitting the output of the difference amplifier to be varied so as to adjust the sensivity of the system to different positions of the operator's hand R.

Abstract: Disclosed is an on-chip test device for testing the thickness of gate oxides in transistors. A ring oscillator provides a ring oscillator output and an inverter receives the ring oscillator output as an input. The inverter is coupled to a gate oxide and the inverter receives different voltages as power supplies. The difference between the voltages provides a measurement of capacitance of the gate oxide. The difference between the voltages is less than or equal to approximately one-third of the difference between a second set of voltages provided to the ring oscillator. The capacitance of the gate oxide comprises the inverse of the frequency of the ring oscillator output multiplied by the difference between the voltages, less a capacitance constant for the test device. This capacitance constant is for the test device alone, and does not include any part of the capacitance of the gate oxide. The measurement of capacitance of the gate oxide is used to determine the thickness of the gate oxide.

Abstract: A measuring apparatus for measuring a semiconductor wafer, or a film or coating thereon, includes an electrically conductive wafer chuck and a probe having a probe body defining an internal cavity in fluid communication with an electrically conductive and elastic or resilient membrane. The membrane and a topside of the semiconductor wafer are moved into spaced relation when the semiconductor wafer is supported by the wafer chuck. A pressure of fluid supplied to the internal cavity of the probe body is selectively controlled whereupon the membrane expands into contact with the topside of the semiconductor wafer. A suitable test stimulus is applied to the membrane and the semiconductor wafer and the response of the semiconductor wafer to the test stimulus is measured.

Abstract: The invention is a system for determining the presence of ice on the surface of a structure. The system includes a guard layer mounted to the surface. A non-conductive layer is mounted on top of the ground plane. First and second electrodes made of a resistive material mounted on the non-conductive layer. First and second electrical leads having first ends of attached to first and second electrodes, respectively. The first and second leads having impedance equal to the impedance of the first ends thereof with the impedance of the first and second leads decreasing toward the second ends thereof.

Abstract: Systems and methods are provided for determining whether a volume of biological sample is adequate to produce an accurate analyte concentration measurement. Certain such systems and methods provide the additional function of compensating for a sample volume determined to be less than adequate in order to proceed with an accurate analyte concentration measurement. The present invention is employed with a biosensor, such as an electrochemical test strip to which the sample volume of biological solution is deposited, and a meter configured to receive such test strip and to measure the concentration of selected analytes within the biological sample.

Abstract: A pocket-sized object finder has a compact housing containing a battery, circuitry and a capacitor plate for detecting an object hidden behind a wall. The battery powered circuitry includes multiple signal indicators that illuminate in a serial manner when the object is being detected. The signal indicators are successively tapered and are mounted at a front side of a tapered end of the housing. The capacitor plate is disposed in the housing along its rear wall and is responsive to variations in capacitance that occur as the object finder is brought near and over the object. The compact housing defines a cavity with a width that is no more than two inches and one third its length. A removable access door, with a pocket clip, at an end opposite the signal indicators allows access to the battery within the housing cavity.

Abstract: A capacitance fuel-gauging system has a capacitive probe and a reference capacitor charged in opposite senses from respective dc voltage sources via switches operated in antiphase. Two further switches alternately discharge the capacitors to a 0 volts rail. The outputs of the probe and the reference capacitor are connected to a summing node, which is connected to an amplifier via a pair of switches operated in antiphase to rectify the output. The amplifier connects to a processor, which controls the relative outputs of the voltage sources and provides an output indicating the value of the probe.

Abstract: An apparatus and method are provided for acquiring the nature of a toner particle layer in a printer or copier. An apparatus and a method are also provided for acquiring the moisture content of a carrier material in a printer or copier. A toner particle layer is transported forward between two capacitor plates arranged next to one another and a cooperating electrode. In a first switch status, the first and the second capacitor plate are charged with voltages opposite one another. In a second switch status, the first and the second capacitor plate are electrically connected to one another, whereby the remaining charge is identified and conclusions about the nature of the toner layer are drawn therefrom.

Abstract: A system for detecting overlapped flat objects in a sequence of flat objects have at least one of their edges exposed for viewing as they pass along a feed path. The system includes a sensor for generating a signal in response to detecting a flat object in the feed path and a camera responsive to the signal for capturing a digital image of the exposed edges of the detected flat object in the feed path. A vision system is coupled to the camera for receiving the digital image. The vision system analyzes at least a portion of the image to determine a pixel density variation along a direction perpendicular to the edges and uses the pixel density variation to output an indication of the number of edges in the image.

Abstract: The present invention includes capacitive film thickness measurement devices and measurement systems. The invention also includes machines or instruments using those aspects of the invention. The present invention additionally includes methods and procedures using those devices of the present invention. The present invention discloses a capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin-film rigid disks. Using the present invention, variations in lubricant thickness on the Angstrom scale or less may be measured quickly and nondestructively.

Abstract: Capacitive film thickness measurement devices and measurement systems used in machines or instruments. A capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin-film rigid disks. Variations in lubricant thickness on the Angstrom scale or less may be measured quickly and nondestructively.

Abstract: The present invention includes capacitive film thickness measurement devices and measurement systems. The invention also includes machines or instruments using those aspects of the invention. The present invention additionally includes methods and procedures using those devices of the present invention. The present invention discloses a capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin-film rigid disks. Using the present invention, variations in lubricant thickness on the Angstrom scale or less may be measured quickly and nondestructively.

Abstract: A system and method for adjusting the targeting of superabsorbent material in absorbent cores based on the timing of a cutting device are disclosed herein. After targeting superabsorbent material into a segment of absorbent core material, a first sensor is used to determine a change in concentration of superabsorbent material over the length of the segment, or alternatively, a rate-of-change in the concentration is determined. The change in concentration, or rate-of-change, can be interpreted as the timing of the superabsorbent material targeting. A second sensor is used to determine the timing of a cutting device used to separate the segment from the remaining absorbent core material. The timing of the targeting of the superabsorbent material can then be synchronized with the timing of the cutting device for targeting of superabsorbent material in subsequent segments of the absorbent core material.

Abstract: A device for locating an object behind a wall lining includes a housing having a front portion adapted to fit substantially in the palm of a users hand. Operating switches are located in juxtaposition the grip portion so as to be operable by the user without substantially altering a grip on the housing. The device also includes a sensor comprising a first capacitor plate and a pair of second capacitor plates. The capacitor plates are arranged vertically, and calibrated by a Pulse Width Modulator and integrator. Operating electronics are incorporated into an Application Specific Integrated Circuit.

Abstract: A method for capacitively measuring the thickness of multi-layer films (10), the layers (32, 34) the dielectric constants of which differ at least at a particular temperature, wherein, in addition to the capacitive measurement, at least one further thickness measurement is carried out under different conditions, and wherein the thicknesses (d1, d2) of the individual layers is determined by comparing the measurement results and by means of the different dielectric constants.

Abstract: The invention is a system for determining the presence of ice on the surface of a structure. The system includes a guard layer mounted to the surface. A non-conductive layer is mounted on top of the ground plane. First and second electrodes made of a resistive material mounted on the non-conductive layer. First and second electrical leads having first ends of attached to first and second electrodes, respectively. The first and second leads having impedance equal to the impedance of the first ends thereof with the impedance of the first and second leads decreasing toward the second ends thereof.

Abstract: Disclosed is a wafer containing a semiconductor substrate, at least one metal layer formed over the semiconductor substrate, and at least one electrical sensor embedded at least one of on and in the wafer to facilitate real time monitoring of the metal layer as it progresses through a subtractive metallization process. The system contains a wafer comprising at least one metal layer formed on a semiconductor substrate, at least one electrical sensor in contact with the wafer and operable to detect and transmit electrical activity associated with the wafer, and an electrical measurement station operable to process electrical activity detected and received from the electrical sensor for monitoring a subtractive metallization process in real-time.

Abstract: A method for measuring the film thickness with the help of a measuring head (12), which is held with a holding device (14) against the film (10), so that the latter is deflected, wherein the reaction force (F), exerted by the film (10) on the measuring head (12), is measured and controlled to a specified nominal value by the movement of the measuring head.

Abstract: A hand held subsurface object locator has a pocket sized housing that contains circuitry and a power source for electrically detecting substratum objects hidden behind a surface. The housing is preferably less than two inches wide and at least three times as long as it is wide. The housing has a pocket clip preferably affixed to a battery compartment door at one end of the housing and the other end of the housing is tapered and includes a plurality of tapered indicators.

Abstract: During a CMP operation, vibration-caused variations in the forces holding a wafer against a polishing pad, and/or relatively moving the pad and the wafer are measured and the standard deviation thereof is used to minimize or eliminate the deleterious effects of the vibrations.

Abstract: The present invention relates to a semiconductor device, and more particularly, to a test pattern for evaluating a process of silicide film formation. The test pattern in accordance with the present invention includes: a silicon substrate having an active region and a field region; a first pattern composed of a cross resistor pattern of a polycide layer formed on the field region; and a second pattern composed of polycide layer and a silicide layer formed on the active region. The second pattern includes: a pair of polycide patterns composed of a first polycide strip and a second polycide strip extended in parallel, being spaced from each other a predetermined interval on an insulating film formed on the active region; and an active silicide strip formed between the first polycide strip and the second polycide strip.

Abstract: A sensor for the capacitive measurement of film thicknesses, with a drum (10), which rolls along the film (12) and has at least one measuring capacitor (C1-C4), the plates of which are disposed in the peripheral surface of the drum (10), so that its capacitance is effected by the thickness of the firm, and with a transformer (26), for transmitting the measurement signal from the rotating drum (10) to the stationary part (28), where an oscillator (OSZ1-OSZ4), which is integrated in the drum (10), generates a frequency signal (24), which depends on the capacitance of the measuring capacitor (C1-C4).

Abstract: A capacitance gauge for measuring changes in the thickness of dielectric film, such as plastic film, is automatically calibrated by utilizing a direct-measurement sensor method or a contact-type sensor method alongside the capacitance sensor assembly. The direct-measurement sensor and the capacitance sensor measure the same point on the film sample, and the capacitive calibration reading is correlated to the direct-measurement sensor reading to automatically calibrate the capacitive sensor. An improved film transport assembly for serially examining plastic film material which eliminates errors in thickness measurement location and eliminates variation in distance between individual sensor readings, while at the same time allowing accurate positioning of the film in the sensors.

Abstract: The subject of the invention is a coating thickness gauge with at least one measuring probe (14) which has at least one sensor (15, 15′) as well as a device for the zero adjustment and/or calibration. The coating thickness device (10) is equipped with means to automatically activate zero adjustment and/or calibration when an interaction especially a contact or a relative movement between a sensor (15, 15′) and a reference plate (11, 11′).

Abstract: An apparatus and method for determining a position and/or orientation of a conductor disposed in a conductive fluid. A plurality of electrodes disposed about the conductor and preferably being in contact with the conductive fluid are used to provide an electrical path between each electrode and the conductor. In one embodiment, resistances between each electrode and conductor are determined through use of a signal processing circuit. In another embodiment, capacitances between each electrode and the conductor are determined using a similar signal processing circuit. Once the resistances or capacitances are determined, the position of the conductor can be determined based on these values in combination with parameters relating to the configuration of the electrodes and conductor, as well as characteristics of the conductive fluid. In one implementation, the invention may be used in free space optical communication systems, whereby the position of the end portion of the fiber optic cable can be determined.

Abstract: The present invention includes capacitive film thickness measurement devices and measurement systems used in machines or instruments. A capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin-film rigid disks. Using the present invention, variations in lubricant thickness on the Angstrom scale or less may be measured quickly and nondestructively.

Abstract: This invention is directed to a method of making a capacitive distance sensor that includes one or more sensor cells each with first and second capacitor plates. The method includes determining an expected range of sizes of objects the sensor will be used to detect and determining a total perimeter value for each of a plurality of capacitor patterns. Each capacitor pattern includes a different arrangement of the first and second capacitor plates and the total perimeter value is the sum of the perimeter values for the first and second capacitor plates. The method selects one of the capacitor patterns based on the expected size of the object and on the total perimeter values determined for the capacitor patterns. The selecting step includes selecting whichever one of the capacitor patterns has the largest total perimeter value if the object is smaller than each of the one or more sensor cells.

Abstract: A system and method are disclosed for detecting the occurrence of an external event. The system eliminates the need for users to adjust amplifier offsets as well as detection thresholds by continually analyzing the signal and optimizing the offset and threshold values accordingly. Additionally, the system detects the external events in a noisy environment when the duration of the events vary by several orders of magnitude by employing cascaded difference filters.

Abstract: In a measuring circuit for a capacitive sensor for distance measurement and/or space monitoring comprising sensor wire and shielding electrode, a sine signal is applied to the shielding electrode. The sensor wire is connected, via a shielded cable, with one input of an input amplifier which serves as current-voltage converter and whose supply voltage is likewise influenced by the sine signal. The output of the input amplifier is connected with one input of a phase-dependent rectifier arrangement, the sine signal is applied to the other input of the phase-dependent rectifier arrangement, and its output is connected to an analog-to-digital converter.

Abstract: First and second dielectric constants, e1 and e2 respectively, for first and second dielectric materials forming a MOS (metal oxide semiconductor) stack are determined. First and second test MOS stacks having first and second total effective oxide thickness, EOTA and EOTB, respectively, are formed. The first and second test MOS stacks include first and second interfacial structures comprised of the second dielectric material with first and second thickness, T2A and T1A, respectively. In addition, the first and second test MOS stacks include first and second high-K structures comprised of the first dielectric material with first and second thickness, T2B and T1B, respectively. The thickness parameters EOTA, T1A, T2A, EOTB, T1B, and T2B of the test MOS stacks are measured. The dielectric constants, e1 and e2, are then determined depending on relations between values of EOTA, T1A, and T2A, and between values of EOTB, T1B, and T2B.

Abstract: One embodiment of the invention is a capacitive sensor for sensing the amount of material in a container. This embodiment includes an oscillator that generates an oscillating signal. This oscillator includes an integrating amplifier that is formed by (1) an operational amplifier that has a low-impedance output and a virtually-grounded input, and (2) a capacitor that has a capacitance which depends on the amount of material in the container. The capacitor connects between the low impedance output and the virtually-grounded input of the operational amplifier In some embodiments, the operational amplifier includes a first amplifier and a second amplifier that are connected in series, with an output of the second amplifier fed back through the capacitor to the input of the first amplifier.

Abstract: The present invention includes capacitive film thickness measurement devices and measurement systems. The invention also includes machines or instruments using those aspects of the invention. The present invention additionally includes methods and procedures using those devices of the present invention. The present invention discloses a capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin-film rigid disks. Also disclosed is a device and technique for determining film thickness by suspending the film in a liquid dielectric. Using the present invention, variations in lubricant thickness on the Angstrom scale or less may be measured quickly and nondestructively.

Abstract: Bias charge is injected from a bias power supply line 3 into a detecting electrode 11 constituting an electrostatic capacitance element between an object to be detected to accumulate charge in accordance with its electrostatic capacitance, and when the charge is distributed between the electrostatic capacitance element and a capacitance element 12 which has been reset to a reset potential, a holding voltage of the capacitance element 12 changes in accordance with the amount of charges accumulated in the detecting electrode 11, and thus a signal is outputted regarding the change in holding voltage as an amount of change in gate potential of a source follower amplifier element 13, thereby detecting the capacitance of the electrostatic capacitance element between the object to be detected and the detecting electrode 11.

Abstract: A distance sensor has a capacitive element in turn having a first capacitor plate which is positioned facing a second capacitor plate whose distance is to be measured. In the case of fingerprinting, the second capacitor plate is defined directly by the skin surface of the finger being printed. The sensor comprises an inverting amplifier, between the input and output of which the capacitive element is connected to form a negative feedback branch. By supplying an electric charge step to the input of the inverting amplifier, a voltage step directly proportional to the distance being measured is obtained at the output.