Capacitance Patents (Class 73/335.04)
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Patent number: 7114848Abstract: An environment sensor (11) for measuring the temperature and humidity can be miniaturized and can respond at high speed. The environment sensor (11) includes a temperature sensing portion (111) having a temperature-sensitive material (1) made of a metal oxide, and a humidity-sensing portion (112) which is formed on the same substrate as the temperature sensing portion (111) and measures the ambient humidity by using a change in electrical characteristics. At least one of a pair of electrodes (2, 3) of the temperature sensor (111) is integrated with an electrode of the humidity-sensing portion (112).Type: GrantFiled: July 8, 2004Date of Patent: October 3, 2006Assignee: Canon Kabushiki KaishaInventor: Norio Kaneko
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Patent number: 7077004Abstract: A method and a device for measuring humidity may be suitable for determining the relative humidity in the high-humidity range. The device includes a sensor device, as well as a circuit connected to the same. The sensor device includes a capacitive humidity-sensor element, a temperature-sensor element, and a heating element, the humidity-sensor element being heated in at least one part of the humidity-measuring range. The ambient temperature is further ascertained by the circuit, from the heating power required in the heating mode, as well as from the measured, local sensor device temperature, in order to further determine the relative humidity.Type: GrantFiled: August 2, 2004Date of Patent: July 18, 2006Assignee: E+E Elektronik Ges.m.b.HInventor: Helmut Mitter
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Patent number: 7051574Abstract: A system for monitoring water concentration in gaseous sample is disclosed. It is readily applicable in the synthesis of biopolymer arrays/microarrays involving the use of water-sensitive reagents. A flow cell is provided in which a capacitance sensor is placed separate from a production or synthesis environment. Sample and dry gas may be provided to the flow cell via conduits and valves or a manifold system. Dry gas, such as N2, is used to dry the sensor or simply to maintain it in a dried condition. The same gas may be used to drive an optional venturi pump to draw sample for measurement into the cell from the synthesis environment.Type: GrantFiled: November 16, 2004Date of Patent: May 30, 2006Assignee: Agilent Technologies, Inc.Inventor: Bill J. Peck
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Patent number: 7049829Abstract: In a method of determining air humidity, a corrected moisture signal is calculated for a moisture signal (Hi) ascertained from electrical properties of a capacitive moisture measuring element. In a measuring phase (30) with rising relative air humidity (RH), the corrected moisture signal is the current moisture signal (Hi) increased by a correction value, whereas in a measuring phase (31) with falling relative air humidity (RH) the corrected moisture signal is the current moisture signal (Hi) reduced by a correction value. Depending on the respective properties of the moisture measuring element and the required degree of measuring accuracy, the correction value is constant or is taken into consideration in dependence on the relative air humidity RH. This method provides a higher level of measuring accuracy with a moisture sensor equipped with the moisture measuring element.Type: GrantFiled: October 14, 2003Date of Patent: May 23, 2006Assignee: Siemens Building Technology AGInventor: Yves Lüthi
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Patent number: 7032448Abstract: A capacitive humidity sensor includes a detection portion and a reference portion. The detection portion includes detection electrodes and a moisture sensitive film. The reference portion includes reference electrodes and a moisture permeation film as a capacitance adjusting film. The capacitive humidity sensor detects humidity by converting a capacitance difference between a capacitance of the detection electrodes and a capacitance of the reference electrodes to an electric signal by using a capacitance-voltage conversion circuit. The moisture permeation film reduces offset voltage of the capacitive humidity sensor. Thus, an offset compensation circuit or the like is not required.Type: GrantFiled: March 11, 2004Date of Patent: April 25, 2006Assignee: Denso CorporationInventor: Kazuaki Hamamoto
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Patent number: 7028531Abstract: A sensor arrangement is suitable for detecting if a windscreen of a motor vehicle is fogging. The sensor arrangement includes a heat conducting layer disposed on a supporting surface, the layer exhibiting good heat conducting properties. A support plate is arranged on top of the heat conducting layer, including a recess and several electrical conductor tracks. A moisture-sensitive sensor element is arranged in the region of the recess of the support plate. The sensor element is electroconductively connected to the conductor tracks on the support plate. The temperature difference between the sensor element and the supporting plate may not exceed a given limit when measurement occurs.Type: GrantFiled: February 1, 2001Date of Patent: April 18, 2006Assignee: E+E Elektronik Ges.m.b.H.Inventor: Gerhard Nikolaus
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Patent number: 6981405Abstract: A device for determining moisture has an LC-oscillating circuit as a transducer and an oscillator for exciting the oscillating circuit. Further, the device for determining moisture has a tuning device for frequency-wise tuning the oscillator and a measuring and evaluation circuit to determine an attenuation condition of the oscillator and to provide a signal that is proportional to a degree of moisture at the transducer. The transducer and the oscillator are coupled in a contact-free manner.Type: GrantFiled: June 7, 2002Date of Patent: January 3, 2006Assignee: Vogt Electronic AGInventor: Willi Wimmer
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Patent number: 6842018Abstract: A transducer comprising at least one planar capacitor with a thin coverlayer of material selected to maximize electric field coupling between cooperating capacitor electrodes within a region external to a principal surface of the coverlayer. Preferred coverlayer materials have low values of moisture absorption, surface free energy, permittivity, dielectric dissipation, and electrical conductance. According to one embodiment of the invention, a driven shield further enhances electric field coupling over and in a region external to the principal surface. The transducer also can promote a physical change in specific adsorbates and materials and simultaneously detect and measure an effect of the induced change. Applications for the transducer of the invention include the measurement of the moisture content of grain and bulk stored commodities, humidity, a dew point temperature, the onset of condensation and rates of adsorption and desorption.Type: GrantFiled: April 30, 2003Date of Patent: January 11, 2005Inventor: Robert B. McIntosh
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Publication number: 20040194546Abstract: A capacitive humidity sensor comprising a humidity sensitive film made of an organic polymer resin and provided on a conductive substrate serving as a lower electrode, a moisture permeable upper electrode provided on the humidity sensitive film, and a lead wire electrically connected to the upper electrode is characterized in that the area for the junction of the upper electrode and the lead wire is 2.5 mm2 or less and/or 10% or less of the total area of the upper electrode.Type: ApplicationFiled: February 20, 2004Publication date: October 7, 2004Inventor: Masashi Kanehori
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Patent number: 6796166Abstract: A sensing device formed upon a substrate, including a method of forming the sensing device. A substrate can be provided, which is formed from a polymer. A sensor circuit can then be patterned and formed upon the substrate. One or more carbonized filaments can also be formed upon the substrate for use with the sensor circuit. The sensor circuit itself can comprise a capacitive type sensor circuit. A polymer can be coated over the sensor circuit and circuit components thereof to form an all polymer sensor for use in detecting chemical agents. Such a hygrosensitive polymer can comprise, for example, HMPTAC (2-hydroxy-3-methacryloxypropyl trimethylammonium chloride). The all polymer sensor formed thereof can also be utilized as a humidity sensor. The polymer can be laser carbonized by an argon ion laser to form the plurality of carbonized filaments.Type: GrantFiled: December 2, 2002Date of Patent: September 28, 2004Assignee: The United States of America as represented by the Secretary of the ArmyInventors: Augustus Way Fountains, III, John M. Ingram, James A. Nicholson
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Publication number: 20040182153Abstract: A capacitive humidity sensor includes a detection portion and a reference portion. The detection portion includes detection electrodes and a moisture sensitive film. The reference portion includes reference electrodes and a moisture permeation film as a capacitance adjusting film. The capacitive humidity sensor detects humidity by converting a capacitance difference between a capacitance of the detection electrodes and a capacitance of the reference electrodes to an electric signal by using a capacitance-voltage conversion circuit. The moisture permeation film reduces offset voltage of the capacitive humidity sensor. Thus, an offset compensation circuit or the like is not required.Type: ApplicationFiled: March 11, 2004Publication date: September 23, 2004Applicant: DENSO CORPORATIONInventor: Kazuaki Hamamoto
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Publication number: 20040177685Abstract: A pair of comb-tooth-shaped electrodes are formed on the same plane of a semiconductor substrate. A protection film composed of silicon nitride film and humidity sensing film of polyimide-based polymer covers the pair of comb-tooth-shaped electrodes. A moisture-permeable film having a higher dielectric constant than the humidity sensing film and also having moisture-permeability is formed on the humidity sensing film. By this structure, the variation of the electrostatic capacitance between the pair of comb-tooth-shaped electrodes which varies in accordance with humidity variation in the humidity sensing film is increased.Type: ApplicationFiled: March 4, 2004Publication date: September 16, 2004Applicant: DENSO CORPORATIONInventors: Hisanori Yokura, Inao Toyoda
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Patent number: 6756793Abstract: A capacitance type moisture sensor having the capability of accurately detecting amounts of water is provided. This sensor has a sensor housing having an electrically-insulating wall, a pair of electrodes disposed on the sensor housing, and a circuit unit. An outer surface of the electrically-insulating wall faces a space where the amounts of water should be detected. On an inner surface of the electrically-insulating wall, at least one of the electrodes is formed. An electric field developed between the electrodes is defined as a moisture detecting region. The circuit unit includes a capacitance detecting circuit for detecting a capacitance value between the electrodes, which changes in response to the amounts of water in the moisture detecting region, and an output circuit for providing an electrical signal corresponding toe the amounts of water according the capacitance value detected by the capacitance detecting circuit.Type: GrantFiled: July 3, 2001Date of Patent: June 29, 2004Assignee: Matsushita Electric Works, Ltd.Inventors: Atsuyuki Hirono, Hideo Mori, Yuji Takada, Keisuke Yoshikawa
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Patent number: 6742387Abstract: A capacitive humidity sensor includes a pair of opposed electrodes on a substrate. A humidity-sensitive film covers the electrodes. The electrodes are comb-shaped and interdigitated. Humidity is detected based on the capacitance between the pair of electrodes, which changes with changes according to the humidity in the atmosphere. The uniform width of each tooth in the pair of electrodes is L1, and the uniform distance between a tooth of one of the electrodes and a tooth of the other electrode is L2. When L1 is less than 3 micrometers, L2 is 5 micrometers. When L1 is greater than or equal to 3 micrometers, L2 is less than or equal to 5 micrometers.Type: GrantFiled: November 19, 2002Date of Patent: June 1, 2004Assignee: Denso CorporationInventors: Kazuaki Hamamoto, Inao Toyoda
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Publication number: 20040007049Abstract: A sensor unit comprises a mounting base (1) on which an air moisture sensor (3) and an air temperature sensor (4) are disposed. The air moisture sensor (3) is disposed over a bore (5) of the mounting base and covers the bore (5) at least partially. An intensive thermal coupling between the air moisture sensor (3), air temperature sensor (4) and air mixture to be analysed is produced.Type: ApplicationFiled: August 14, 2003Publication date: January 15, 2004Inventor: Elmar Hoppach
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Patent number: 6647782Abstract: A humidity sensor has two detection electrodes located on a semiconductor substrate and a humidity sensitive film. The capacitance of the film changes in response to humidity. The sensor includes a reference capacitor and a feedback capacitor. An electrode of each capacitor is located beneath one of the detection electrodes to limit the size of the device.Type: GrantFiled: July 15, 2002Date of Patent: November 18, 2003Assignee: Denso CorporationInventor: Inao Toyoda
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Patent number: 6575621Abstract: The invention concerns dew point hygrometers based on condensation of dew on ends of optical fibers, or on surfaces of an optical prism. The invention also concerns a dew sensor for determining the natural dew condensation by optical means and a dew sensor capable of detecting dew by detecting a change in capacitance.Type: GrantFiled: July 13, 2001Date of Patent: June 10, 2003Assignee: Optiguide Ltd.Inventor: Igor Zlochin
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Publication number: 20030094045Abstract: A capacitive humidity sensor includes a pair of opposed electrodes on a substrate. A humidity-sensitive film covers the electrodes. The electrodes are comb-shaped and interdigitated. Humidity is detected based on the capacitance between the pair of electrodes, which changes with changes according to the humidity in the atmosphere. The uniform width of each tooth in the pair of electrodes is L1, and the uniform distance between a tooth of one of the electrodes and a tooth of the other electrode is L2. When L1 is less than 3 micrometers, L2 is 5 micrometers. When L1 is greater than or equal to 3 micrometers, L2 is less than or equal to 5 micrometers.Type: ApplicationFiled: November 19, 2002Publication date: May 22, 2003Inventors: Kazuaki Hamamoto, Inao Toyoda
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Patent number: 6564633Abstract: A method and system relating to an improvement in measuring accuracy of a gas concentration sensor, the method comprising the steps of measuring a parameter of the sensor, the parameter being a resistance or a capacitance, that is sensitive to the gas or its concentration being measured, and simultaneously changing the temperature of the sensor in a cyclic manner. The parameter of the sensor being measured is measured more than two times or continuously during each heating cycle. The measured parameter value is filtered to obtain a signal component associated with the fundamental frequency of the heating cycle for use at a later step, and the thus filtered signal component is used in the correction and/or calibration of actual output signal of the sensor.Type: GrantFiled: December 8, 2000Date of Patent: May 20, 2003Assignee: Vaisala OyjInventor: Lars Stormbom
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Patent number: 6552552Abstract: A capacitance type moisture sensor having the capability of accurately detecting amounts of water is provided. This sensor has a sensor housing having an electrically-insulating wall, a pair of electrodes disposed on the sensor housing, and a circuit unit. An outer surface of the electrically-insulating wall faces a space where the amounts of water should be detected. On an inner surface of the electrically-insulating wall, at least one of the electrodes is formed. An electric field developed between the electrodes is defined as a moisture detecting region. The circuit unit includes a capacitance detecting circuit for detecting a capacitance value between the electrodes, which changes in response to the amounts of water in the moisture detecting region, and an output circuit for providing an electrical signal corresponding toe the amounts of water according the capacitance value detected by the capacitance detecting circuit.Type: GrantFiled: July 3, 2001Date of Patent: April 22, 2003Assignee: Matsushita Electric Works, Ltd.Inventors: Atsuyuki Hirono, Hideo Mori, Yuji Takada, Keisuke Yoshikawa
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Publication number: 20030010119Abstract: A humidity sensor has two detection electrodes located on a semiconductor substrate and a humidity sensitive film. The capacitance of the film changes in response to humidity. The sensor includes a reference capacitor and a feedback capacitor. An electrode of each capacitor is located beneath one of the detection electrodes to limit the size of the device.Type: ApplicationFiled: July 15, 2002Publication date: January 16, 2003Inventor: Inao Toyoda
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Patent number: 6469525Abstract: An electrical system for measuring humidity which is capable of measurements accurate to +/−6 percent from board to board. The accuracy provided by this electrical system makes it possible to correlate errors in data on backup magnetic tapes to variations in humidity. The electrical system consists of an oscillator whose frequency is dependent on the capacitance of a capacitor used in the circuit. The capacitance value of the capacitor is dependent on the relative humidity. The frequency of the oscillator is translated to a humidity value by an electronic counter and a microprocessor.Type: GrantFiled: January 4, 2001Date of Patent: October 22, 2002Assignee: Hewlett-Packard CompanyInventors: Jonathan C. Baiardo, Kelly John Reasoner, Duane L. Harmon, Richard A Irwin
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Patent number: 6450026Abstract: The invention concerns a sensor comprising two electrodes (1, 3a) separated by a dielectric material (2). One electrode (3a) being produced by using a non-porous metal sheet, the other electrode (1) being advantageously made of a non-metallic porous material made conductive and the dielectric material being advantageously in the form of a multilayer polymer film (2). The resulting sensor can be adjusted to the desired value by a particular capacitor by reducing the useful surface of the porous electrode (1). The reduction step carried out by simply scraping or eroding the material constituting the porous electrode (1).Type: GrantFiled: December 18, 2000Date of Patent: September 17, 2002Inventor: Jean Desarnaud
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Patent number: 6437582Abstract: A device for the measurement of the moisture of harvested crop including a measurement capacitor (52) with two spaced electrodes (78, 80, 82), between which harvested crop can be introduced. The capacitor (52) is connected to an inductance (104) of a resonance circuit (106). For improved precision, it is proposed that the resonance circuit (106) be supplied with a measurement signal in the form of an alternating voltage with variable frequency and that a parameter of the resonance circuit (106), preferably resonant frequency dependent upon the capacitance of the capacitor (52), be detected at various frequencies and used for the determination of the moisture.Type: GrantFiled: July 18, 2000Date of Patent: August 20, 2002Assignee: Deere & CompanyInventors: Hans-Jürgen Rode, Arnold Rutz
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Publication number: 20020005068Abstract: A hygrometer includes a capacitive sensor with a capacitance that changes in response to water or ice forming on its surface. A controller controls a thermoelectric module to cool the sensor until dew forms on the surface of the sensor. The controller then controls the thermoelectric module to heat or cool in response to a sharp change in the capacitance of the sensor, which occurs at the dew (or frost) point temperature of the ambient air, until the sensor reaches equilibrium at the dew (or frost) point temperature.Type: ApplicationFiled: May 11, 2001Publication date: January 17, 2002Inventor: Kenneth G. Libbrecht
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Patent number: 6285198Abstract: A moisture sensor for an agricultural combine comprises a chamber having an inlet and an outlet and a paddle wheel flow controller located adjacent to the outlet. The paddle wheel flow controller is rotated by an electric motor which is controlled by an electronic controller. Grain from the clean grain elevator is directed through the inlet of the chamber past a capacitance sensor comprising a first, second and third plates. By measuring the capacitance of the grain, the moisture in the grain can be determined.Type: GrantFiled: July 3, 1997Date of Patent: September 4, 2001Assignee: Deere & CompanyInventors: Frederick William Nelson, Kent Robert Hawk, Wayne Farrior Smith, Terence Daniel Pickett