Abstract: A sensor for indicating changes in the physical presence of persons or objects and including at least two electrically conductive sheets of material that are spaced mutually apart on an electrically non-conductive carrier sheet or the like. A sensing circuit is also provided for sensing changes in the capacitance between the electrically conductive sheets.

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 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: A device for sensing media thickness using capacitance measurements includes first and second supports that are moveable relative to each other and a variable capacitance capacitor comprising first and second electrodes that have a variable gap disposed between the electrodes and a dielectric medium disposed in the variable gap. The dielectric medium can be a gas or a vacuum. The first and second electrodes are disposed on a portion of the first and second supports respectively and are disposed opposite each other in substantially facing relation. The electrodes are spaced apart by a first distance. When a media whose thickness is to be measured and the supports are urged into contact with one another, the electrodes are displaced to a second distance.

Abstract: An ice detector includes a pair of electrodes connected by a pair of leads to a control unit which measures the admittance between leads to thereby sense and detect the presence of ice and other contaminants formed on top thereof utilizing a detection circuit. The electrodes are integrated into patch which can be placed at different locations on an aircraft.

Abstract: A method is disclosed for processing, optimization, calibration, and display of measured dielectrometry signals. A property estimator is coupled by way of instrumentation to an electrode structure and translates sensed electromagnetic responses into estimates of one or more preselected properties or dimensions of the material, such as dielectric permittivity and ohmic conductivity, layer thickness, or other physical properties that affect dielectric properties, or presence of other lossy dielectric or metallic objects. A dielectrometry sensor is disclosed which can be connected in various ways to have different effective penetration depths of electric fields but with all configurations having the same air-gap, fluid gap, or shim lift-off height, thereby greatly improving the performance of the property estimators by decreasing the number of unknowns.

Abstract: A system for electrically measuring variations over a flexible web has a capacitive sensor including spaced electrically conductive, transmit and receive electrodes mounted on a flexible substrate. The sensor is held against a flexible web with sufficient force to deflect the path of the web, which moves relative to the sensor.

Abstract: The distance sensor has a capacitive element (33, 34) in turn having a first plate (23) which is positioned facing a second plate (18) whose distance is to be measured. In the case of fingerprinting, the second plate is defined directly by the skin surface of the finger being printed. The sensor includes an inverting amplifier (13), between the input and output of which the capacitive element (33, 34) 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.

Abstract: An apparatus for converting capacitance in a capacitive sensor into a voltage signal. A capacitive sensor monitors a physical parameter. A capacitance of the sensor varies with the physical parameter. A voltage supply applies an alternating voltage to the capacitive sensor, which creates an output signal from the sensor. A modulator modulates the output signal, which produces a voltage signal that corresponds to the capacitance of the sensor.

Abstract: A method for measuring film thicknesses 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: An apparatus and method for evaluating the performance of a test dielectric material for use as a gate dielectric. The method comprises exposing a coated layer of the dielectric to a concentration of atomic hydrogen. The method may comprise (a) measuring an initial value of interface-state density in the test dielectric, (b) exposing the coated test dielectric to a concentration of atomic hydrogen in a remote plasma, and then (c) measuring a post-exposure value of interface-state density in the test dielectric. Steps (b) and (c) may be repeated with incrementally higher concentrations of atomic hydrogen to determine a rate of change in interface-state density value as a function of atomic hydrogen concentration, which may then be related to the projected charge-to-breakdown or time-to-breakdown of the test dielectric layer when the dielectric is used as the gate dielectric.

Abstract: A distance sensor has a capacitive element in turn having a first armature which is positioned facing a second armature whose distance is to be measured. In the case of fingerprinting, the second armature 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.

Abstract: An electrostatic capacitive encoder includes a scale (1) and a sensor head (2), which is arranged opposing to and relatively movable to the scale (1). A plurality of protrusions (24) for sliding, processed in a certain pattern, are located on a flat region surrounding a transmitting electrodes (21) and receiving electrodes (22) of the sensor head (2).

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: Thickness of a wafer is monitored during grinding. A conductive plate is located below the wafer during grinding. One or more capacitive sensors are located above the wafer during grinding. A monitoring device monitors capacitance of the conductive plate and the capacitive sensor.

Abstract: A device for locating the edges of wall studs includes a comparison circuit connected to each of three capacitive elements. As the device is moved along a wall, the comparison circuit monitors the relative charge time associated with each capacitive element, the charge times providing an indication of the relative capacitances of the three capacitive elements. Changes in the relative capacitances of the three elements as the device is moved along a wall are due to a change in the dielectric constant of the wall, which normally results from the presence of a wall stud behind the surface over which the device is moved. The comparison circuit uses differences in the measured relative capacitances of the first, second, and third capacitive elements to locate the edges of the stud.

Abstract: A circuit arrangement for measuring the diameters of metal bodies is provided which permits reliable and stable measurement of changes in diameter in a simple way. Measuring signals of relatively high accuracy are formed by compensating for environmental parameters such as ambient temperature and humidity. A dynamic reference signal which depends on the environmental parameters is formed for this purpose.

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.

Abstract: The disclosure relates to a device for measuring properties of a textile product in a measuring gap in which the textile product is inserted. On each of its surfaces the measuring gap has an electrode of a measuring capacitor, between which the product is inserted, an electrode of a compensation capacitor and a conductor. Disturbing influences can be effectively compensated by this arrangement.

Abstract: Apparatus for resolving movement of a mass within a defined space utilizes at least one electrode proximate to the space to be observed. An AC signal is applied to the electrode, and the current measured from that electrode and also to any other electrodes included in the system, and which are effectively connected to the ground return of the AC-coupled electrode. A person (or object) to be sensed intercepts a part of the electric field extending beween the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed person, whether or not the person provides a grounding path, and the geometry of the distributed electrodes. Given the nonlinear spatial dependence of the field, multiple electrodes can reliably distinguish among a set of expected cases.

Abstract: Apparatus for measuring the length of a transmission cable carrying primary and inverted multilevel transmission signals. A counter is arranged to count timing signals from the beginning of the measuring process while a filter extracts a high frequency signal component from the primary and inverted multilevel transmission signals. The extracted high frequency signal component is used to charge a capacitor. A comparator compares the level of charge of the capacitor to a reference level and issues a stop counting signal to the counter when charge of the capacitor equals the reference level. The count of the timing signals in the counter when counting halts is proportional to cable length.

Abstract: A quasi-electrostatic sensing system surrounds an electrically conductive mass with an electric field, the magnitude of which is sensed at one or more locations to resolve a property of interest concerning the mass. The object intercepts a part of the electric field extending beween the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed mass, whether or not the mass provides a grounding path, and the geometry of the distributed electrodes. Because the response of the field to an object is a complex nonlinear function, adding electrodes can always distinguish among more cases. In other words, each electrode represents an independent weighting of the mass within the field; adding an electrode provides information regarding that mass that is not redundant to the information provided by the other electrodes.

Abstract: A dual sensitivity stud sensor senses studs through both thick and thin surfaces. Studs are sensed by detecting a change in the capacitive loading of plates as they are moved along a surface and into proximity with a stud. The sensor informs the operator when the sensor has (incorrectly) been calibrated over a stud. The sensor also informs the operator if the sensor is placed against a surface either too thick or too thin for stud detection. Through use of a digital register, the sensor remains calibrated indefinitely while the sensor is powered on.

Abstract: In-line thickness measurement of a dielectric film layer on a surface of a workpiece subsequent to a polishing on a chemical-mechanical polishing machine in a polishing slurry is disclosed. The workpiece includes a given level of back-end-of-line (BEOL) structure including junctions. The measurement apparatus includes a platen and an electrode embedded within the platen. A positioning mechanism positions the workpiece above the electrode with the dielectric layer facing in a direction of the electrode. A slurry dam is used for maintaining a prescribed level of a conductive polishing slurry above the electrode, the prescribed level to ensure a desired slurry coverage of the workpiece. A capacitance sensor senses a system capacitance C in accordance with an RC equivalent circuit model, wherein the RC equivalent circuit includes a resistance R representative of the slurry and workpiece resistances and the system capacitance C representative of the dielectric material and junction capacitances.

Abstract: A system for detecting a gap of unknown width, the system having an RF signal generator having an output interface that outputs an RF signal and that interfaces with an input portion of a test device that is electromagnetically connected with a first surface of a gap. The system also comprises an RF signal receiver having an input interface that receives an RF signal and that interfaces with an output portion of the test device that is electromagnetically connected with a second surface of a gap. The RF signal receiver generates an electrical output to an output interface when an RF signal is detected. A processor has an input interface that interfaces with the output interface of the RF signal receiver and the processor converts the electrical signal from the receiver into an indication to the user of the presence of a gap in the test device.

Abstract: A halogen lamp of illuminance 150,000 lux or greater and wavelength 1129 nm or less is provided in the vicinity of a probe of an electrostatic capacitative flatness measuring instrument, and illuminates the surface of the wafer under measurement. When the light enters into the bulk, it is converted to excitation energy, which converts the valence electrons of the silicon into conduction electrons. Since the free electrons or positive holes generated from the silicon are overwhelmingly more than the dopant or oxygen donors, the wafer exhibits characteristics similar to metal. That is, electrons are uniformly distributed in all parts of the wafer. When, in this state, the upper face and lower face of the wafer are measured, the relative dielectric constant is fixed in all locations, so all the changes in electrical amount can be measured as changes in distance between the wafer and the probe.

Abstract: The invention relates to an apparatus for measuring the capacitance between at least a conductive part of a wall of a vessel and a measuring electrode situated in the vessel and carrying a measuring voltage, comprising a measuring circuit and a compensating circuit for applying a compensating voltage as nearly as possible the same as the measuring voltage to conductors present in the vicinity of conductors carrying the measuring voltage, wherein the capacitance between the measuring electrode and the vessel wall is connected as frequency determining element in an oscillator, so that the frequency of the measuring signal is related to the value of the capacitance. Frequency is a quantity which can be measured much better, can be determined much more precisely, requires less complicated circuits and can be largely implemented in integrated form.

Abstract: Measuring the limpness of a note is necessary to separate a worn note out of circulation. Several methods are disclosed which can be used either alone or in combination to test for limpness. One method measures the note's ability to reflect light or transmit the light. Another method measures the response of the note to an acoustic wave. Another method measures the note's deflection to a pressure or force. Yet another method measures the dielectric value of the note when placed between the plates of a capacitor. A final method involves measuring the thermal conductivity of the note. In each case, a limp note will produce distinguishable results from a stiff note.

Abstract: A composite capacitive sensor device for use at least up to 1300.degree. C. and 40 bar, including a coaxial cable comprising a conductive sleeve (10) and an inner conductor (21), which are separated by a first insulator (19), and a probe (1) comprising elements which are all refractory and anticorrosive, which are respectively connected to the end portions of said cable and which comprise a metal housing (2) and an electrode (4) having a flat surface (4a) of larger area than the cross-sectional area of the inner conductor, which elements are separated by a second insulator (9) associated with locking means (3, 16) and are secured by means which are all refractory and anticorrosive (11a-11e).

Abstract: A capacitance gauge for measuring changes in the thickness of dielectric film, such as plastic film, is automatically temperature and humidity compensated by utilizing a primary measurement sensor and a reference sensor which monitors changes in perceived capacitance caused by ambient temperature and humidity changes or other environmentally induced interferences. The reference sensor counterbalances in an equal an opposite fashion, and thereby automatically cancels, any imbalance in the primary sensor caused by temperature, humidity, or other, fluctuations. 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 the user of the invention to select from a full variable range of distances between individual sensor readings and also allows accurate positioning of the film in the sensor.

Abstract: A transducer is disclosed which provides distance or position information about a target relative to the transducer. The transducer has first resistor and a first electrode for forming a first capacitive coupling with a target, a second resistor and a second electrode for forming a second capacitive coupling with the target. Signals of opposite phase or polarity are applied to the respective resistor electrode combinations. By applying signals of opposite phase or polarity, no net signal is applied to the target, thereby avoiding problems with cross talk between adjacent transducers.

Abstract: A non-contact capacitive proximity detector includes a sensing plate and detection circuitry electrically coupled to the sensing plate. The detection circuitry comprises an oscillator electrically connected to the sensing plate and signal conditioning circuitry electrically connected to the oscillator. The signal conditioning circuitry includes a coupling capacitor C.sub.1, an envelope demodulator, a first comparator, a delay circuit and a second comparator. When an object is within a predetermined proximity to the sensing plate, the capacitance of the capacitor constituted by the sensing plate and the proximal object is at a level which causes the oscillator to generator an oscillating signal having a sufficient magnitude. The oscillating signal generated by the oscillator is applied to the envelope demodulator by way of the coupling capacitor. The envelope demodulator generates an envelope of the oscillating signal and applies the envelope to he first comparator.

Abstract: Apparatus for inspecting the wall thickness of non-round containers includes capacitive sensors which cooperate with oscillator means to provide voltage signals corresponding to container wall thickness to electronic processors which convert the voltage signals to corresponding thickness values and compare them with the desired thickness values. The apparatus subjects the containers to translational movement through the inspection zone while resisting rotational movement. The sensors have at least one sensor element having capacitive sensor portions that are not in the same plane as other capacitive sensor elements or a single sensor element having portions in more than one plane. The sensor elements may be individual sensor elements which are each adapted to inspect different portions of a container or may, in another embodiment, be a single sensor element. The sensors are adapted to be movably mounted so as to maintain efficient contact with non-round containers during inspection.

Abstract: A capacitive sensor device for use at least up to 1300.degree. C. and 40 bar, including a coaxial cable comprising a conductive sleeve (10) and at least one inner conductor (21) which are separated by an insulator (19), said cable having an end portion (1) of enlarged diameter forming a probe in which the insulator is an anticorrosive refractory element (9, 29) locked by a first and a second anticorrosive refractory metal protection element (5, 4), welded to the sleeve and to said inner conductor, respectively, which second protection element forms an electrode (4) having a flat surface (4a) of an area larger than the cross-sectional area of the end portion of the inner conductor.

Abstract: An ice detection sensor for placement on a surface of a body subject to ig includes a Pyrex glass or silicon block for disposal on the body surface, the block having a cavity therein, a diaphragm bonded to the silicon block and covering the cavity, a drive electrode disposed in the cavity and operable to deflect the diaphragm upon application of voltage between the drive electrode and the diaphragm, and a second electrode operable to detect motion of the diaphragm. The diaphragm is movable by the drive electrode when there is water covering the diaphragm and when the diaphragm is not covered and the diaphragm is not movable by the drive electrode when there is ice covering the diaphragm. The second electrode is adapted to detect movement and non-movement of the diaphragm, whereby to detect whether ice covers the diaphragm.

Abstract: The present invention is an improved ice sensor which is particularly effective in measuring and quantifying non-uniform, heterogeneous ice typically found on aircraft leading edges and top wing surfaces. In one embodiment, the ice sensor comprises a plurality of surface mounted capacitive sensors, each having a different electrode spacing. These sensors measure ice thickness by measuring the changes in capacitance of the flush electrode elements due to the presence of ice or water. Electronic guarding techniques are employed to minimize baseline and parasitic capacitances so as to decrease the noise level and thus increase the signal to noise ratio. Importantly, the use of guard electrodes for selective capacitive sensors also enables distributed capacitive measurements to be made over large or complex areas, independent of temperature or location, due to the capability of manipulating the electric field lines associated with the capacitive sensors.

Abstract: An apparatus for medical diagnosis and/or therapy, includes an electromagnetic obstacle sensor. Due to variations of the ambient temperature and humidity and/or due to the hanging of, for example a cloth around the sensors (16,18), drift of the zero point of the control may occur, so that the approaching of an obstacle by a movable part (6) of the apparatus could be incorrectly interpreted by the apparatus. In order to compensate for such drift there is provided a control unit (25) for automatically controlling the output signal V.sub.o of the receiver (27) back to the zero value in the absence of an object in the vicinity of the movable part (6). This control preferably takes place at a comparatively high speed when a cloth or moisture is moved into the vicinity of the sensors, and at a comparatively low speed upon removal of the cloth or the moisture.

Abstract: A positioning apparatus positions free ends of resilient members. The apparatus couples a capacitance member to the free end and places the capacitance member within an electrode system. A voltage source applies an electric charge to the capacitance member and voltage signals applied to the electrode system generate electric fields which urge the free end to a position of equilibrium between an urging force of said electric field on said electric charge and an internal restoring force of said resilient member. This apparatus is adapted to also be a position sensing apparatus which includes a time-variable signal generator that is coupled to the capacitance member and a current sensor that senses current magnitudes in the electrodes of the electrode system. Each current magnitude is representative of the distance between that electrode and the capacitance member.

Abstract: The present invention relates to a test pattern group and a method for measuring an insulation film thickness utilizing the same, and to the test pattern group comprising at least 3 (three) test patterns having a construction of a capacitor and a method for more precisely measuring the insulation film thickness utilizing the test pattern group, in a method for electrically measuring a capacitance of the insulation film applied to a semiconductor device and converting the measured capacitance to a thickness of the insulating film.

Abstract: The present invention provides a sheet thickness measuring apparatus comprising electrostatic capacity measure means for measuring the electrostatic capacity of a sheet, resistance measure means for measuring a resistance value of the sheet, and calculation means for calculating a thickness of the sheet on the basis of the electrostatic capacity measured by the electrostatic capacity measure means and the resistance value measured by the resistance measure means.

Abstract: A capacitive technique for measuring the thickness of non-conductive, flexible sheet material consists of placing the sheet material over the gap between a pair of coaxial electrodes, the electrodes defining a sensor surface, and keeping the sheet material spaced from the sensor surface by establishing a layer of gas therebetween.

Abstract: The change in thickness of a film on an underlying body such as a semiconductor substrate is monitored in situ by inducing a current in the film, and as the thickness of the film changes (either increase or decrease), the changes in the current are detected. With a conductive film, eddy currents are induced in the film by a generating an alternating electromagnetic field with a sensor which includes a capacitor and an inductor.

Abstract: The measuring device of the invention uses a capacitor polarized by a continuous voltage and conditioned by a continuous charge amplifier, this charge amplifier having a high-band filter structure, preferably of the second order. The technology of the capacitor and the linking cable is coaxial. The tuning of the chain measurement is effected theoretically without needing standardization.

Abstract: According to the preferred embodiment, an erosion and dishing monitor is provided that facilitates the accurate optimization of a planarization process as in semiconductor process. The dishing monitor comprises at least two monitor structure sets embedded in a semiconductor substrate, the monitor structure sets comprising a plurality of monitor structures connected together with a plurality of connective conductors. The erosion monitor comprises a plurality of elongated conductors embedded into a semiconductor substrate, the plurality of conductors having varying conductor widths and adjacent substrate widths.

Abstract: Rotary signal coupling in in-situ monitoring of a chemical-mechanical polishing process. A sensor fixed to a rotatable wafer carrier for creating a signal responsive to the chemical mechanical polishing process is coupled to a bottom half of a rotary transformer fixed to a rotating portion of the polisher. A top half of the rotary transformer, coupled to the bottom half of the rotary transformer, is fixed to a stationary portion of the polisher. The signal from the sensor is thus coupled through the rotary transformer to a process monitor.

Abstract: A capacitive fluid level sensing pipette probe adapted to be used in an automated random access immunoassay analyzer is provided. The pipette probe comprises an elongated shaft having a conductive tip. An integrated circuit chip containing capacitive sensing circuitry is positioned on the pipette probe itself, or in very close proximity. With this arrangement, the sensing circuitry moves with the pipette probe as it is raised and lowered into and out of a vessel containing a liquid. Thus, errors associated with capacitance caused by flexing connector cables is eliminated. Flex tape wiring may be used to carry data from the capacitive sensing circuitry on the pipette probe to the processing board of the automated immunoassay analyzer.

Abstract: A method and apparatus for endpoint detection in removal of a film from a semiconductor wafer is provided, with a sensor for creating a signal responsive to the film removal process, a positive feedback amplifier coupled to the sensor, the positive feedback amplifier having a mode selector, and an analyzer coupled to the positive feedback amplifier.

Abstract: A sensor system is operable for detecting the presence of water in an oil emulsion inside the lower gear unit of a marine engine, and for providing an alarm signal when the presence of water is detected within the gear unit. The sensor system includes a ring oscillator circuit and a symmetrical array of passive input probes which are disposed in the oil/water emulsion inside the oil chamber. Each of the passive input probes is electrically connected to the ring oscillator circuit wherein the probes function as fixed capacitors for measuring the electrical characteristics of the emulsion. When a voltage is applied to the oscillator circuit, the oscillator circuit generates an oscillating signal that circulates at a frequency which varies according to the dielectric-properties of the liquid emulsion. When water is introduced into the chamber, the water is emulsified with the oil thereby changing the electrical characteristics of the oil.

Abstract: A non-intrusive device for attachment to a pipe or vessel through which a fluid flows for monitoring the accumulation of deposits on the interior surface of the pipe or vessel. The device comprises a tubular member having an internal cross-sectional configuration substantially matching that of the pipe or vessel. Additionally, the tubular member is made of an electrically insulating material and having associated therewith three spaced electrodes for monitoring the change of dielectric constant within the pipe or vessel.

Abstract: Apparatus for inspecting non-round annular containers includes elongated capacitive sensors, cooperating oscillators, which convert the sensor signal to a voltage corresponding thereto, and an electronic processor which receives the voltage and determines thickness. A displaceable electromechanical member is operatively associated with the sensor and emits an electrical signal corresponding to the degree of displacement of the sensor by a container being inspected. The electronic processor corrects the thickness determination by an adjustment of container diameter at the specific location where thickness is being monitored in order to compensate for container diameter variations due to the non-round characteristic of the container. In a preferred embodiment, linkage members secured to the rear of the sensor at a plurality of locations cooperate with a single displaceable element which converts the mechanical displacement of the sensor into a corresponding electrical signal.