Humidity Patents (Class 338/35)
  • Patent number: 4528543
    Abstract: A moisture sensitive resistive element includes a substrate made of an electrically non-conductive material, first and second electrodes deposited on the substrate in a spaced relation to each other, and a moisture sensitive film deposited on the substrate covering both the first and second electrodes. The moisture sensitive film is formed by a material given by a formula: [--CH(C.sub.6 H.sub.4 SO.sub.3 X)--CH.sub.2 --].sub.n wherein X is any one of a hydrogen atom, metal atom, ammonium, urea, triethylenediamine, tetramethyleneguanidine and hexamethylenediamine, or formed by a mixture of the above material with a hydrophilic polymer which is any one selected from a group consisting of polyvinyl alcohol, methyl cellulose and polyamide resin.
    Type: Grant
    Filed: March 30, 1984
    Date of Patent: July 9, 1985
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shuji Miyoshi, Takashi Sugihara, Masaya Hijikigawa
  • Patent number: 4520341
    Abstract: A moisture responsive element comprises a moisture responsive organic membrane in contact with electrically conductive members, in which the organic membrane consists essentially of a crosslinked organic polymer having a hydrophilic group. The element has excellent water and moisture resistance, long-term stability and excellent humidity response over a range of humidity from 0 to 100 percent. The moisture responsive element includes a protective layer of cellulose acetate and/or polyvinyl acetate.
    Type: Grant
    Filed: December 2, 1982
    Date of Patent: May 28, 1985
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shuji Miyoshi, Takashi Sugihara, Akihito Jinda, Masaya Hijikigawa
  • Patent number: 4509035
    Abstract: A humidity-sensitive element which has excellent humidity-sensitive characteristics and has a small drift after being exposed to a high humidity for a long period of time. The humidity-sensitive element of the invention includes a porous metal oxide sintered body, a simple substance or an oxide of phosphorus or sulfur carried on the porous metal oxide sintered body, and copper ions carried on the porous metal oxide sintered body.
    Type: Grant
    Filed: November 30, 1983
    Date of Patent: April 2, 1985
    Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
    Inventors: Mituo Harata, Hideaki Hiraki, Shigeki Uno, Kazuo Sakuma, Kiyosi Matsunaga
  • Patent number: 4496931
    Abstract: A thin-film moisture sensor includes a moisture sensitive polymer film formed on a bottom electrode which is carried on a substrate, and a moisture permeable upper electrode formed on the polymer film. The moisture permeable upper electrode is made of an indium (In) thin-film. In another form, the moisture permeable upper electrode is made of a two-layered electrode including an indium (In) thin-film and a gold (Au) thin-film formed on the indium (In) thin-film.
    Type: Grant
    Filed: March 16, 1984
    Date of Patent: January 29, 1985
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Masanori Watanabe, Hisatoshi Furubayashi, Junichi Tanaka, Masaya Hijikigawa
  • Patent number: 4484172
    Abstract: An improved humidity sensitive semiconductor device comprising an insulating base member and a humidity sensitive coating on said base member having at least two spread apart metal electrodes connected thereto, the coating comprising a metal oxide of a lanthanide cobaltate of the formula L.sub.1-x Sr.sub.x CoO.sub.3 where L is a member of the lanthanide series of elements selected from the group lanthanum, cerium, praseodymium, neodymium, promethium, smarium, europium, gadolinium, terbium, sysprosium, holmium, erbium, thulium, ytterbium, and lutetium and x is from about 0 to about 0.5 and an anion selected from the group consisting essentially of the organic anions of monobasic acids, dibasic acids or polybasic acids, inorganic anions and mixtures thereof.
    Type: Grant
    Filed: April 1, 1983
    Date of Patent: November 20, 1984
    Assignee: Arthur D. Little, Inc.
    Inventor: Clark F. Grain
  • Patent number: 4481813
    Abstract: A dew sensor of direct current type and resistance-lowering type with increasing humidity for quick and sharp detection of dewing is provided, which comprises a pair of counterposed electrodes, humidity-sensitive layer of insulating porous metal oxide with a porosity of 20 to 60% provided on and between the counterposed electrodes, and an organic polymer coating layer having a thickness of 0.05 to 2 .mu.m provided on the humidity-sensitive layer.
    Type: Grant
    Filed: October 27, 1982
    Date of Patent: November 13, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Hirayoshi Tanei, Shoichi Iwanaga, Akira Ikegami, Hiroshi Otsu, Hiromi Isonae
  • Patent number: 4482581
    Abstract: The present invention relates to a process for producing a capacitive hygrometer, as well as to a hygrometer obtained by this process.Onto a conductive layer forming the first electrode is deposited a layer of a material with a dielectric constant varying as a function of the quantity of water absorbed. Onto the said dielectric material layer is then deposited a layer with a thickness exceeding 200 .ANG. of a slightly oxidizable metal, which forms the second electrode. The latter is made permeable to water by heat treatment at a temperature close to the softening temperature of the dielectric.Application to the measurement of the relative humidity of air.
    Type: Grant
    Filed: January 19, 1982
    Date of Patent: November 13, 1984
    Assignee: Commissariat a l'Energie Atomique
    Inventors: Andre Lorin, Andre Rosilio, Jean Tanguy
  • Patent number: 4473813
    Abstract: The invention relates to a humidity sensor of electric resistance type whose electric resistance changes in accordance with an ambient humidity, characterized by a protective film of silicone resin provided on the surface of a humidity-sensitive material, and to a method for preparing the same. The protective film of silicone resin is formed by applying a varnish of siloxanes to the humidity-sensitive material and subjecting the varnish to reaction. The varnish can be of one-part curing system or two-part curing system, and desirably the reaction of siloxanes is a cross-linking reaction. The formed protective film is not influenced by swelling or shrinking of the humidity-sensitive material, and is prevented from flowing off due to a temperature rise, or from deposition of dusts, etc.
    Type: Grant
    Filed: September 28, 1982
    Date of Patent: September 25, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kinjo, Shuichi Ohara, Toru Sugawara, Shigeki Tsuchitani
  • Patent number: 4464647
    Abstract: A sintered body for a humidity sensor is formed by baking a blend at 1,000.degree. to 1,400.degree. C., the blend comprising ZnO, Cr.sub.2 O.sub.3, V.sub.2 O.sub.5 and M.sub.2 O where M.sub.2 O is at least one metal oxide selected from Li.sub.2 O, Na.sub.2 O and K.sub.2 O. A pair of electrodes are each attached to the corresponding surface of the sintered body to obtain a humidity sensor of metal oxide which is relatively low in its resistive value and stable in its aging characteristic.
    Type: Grant
    Filed: January 25, 1982
    Date of Patent: August 7, 1984
    Assignees: Marcon Electronics Co. Ltd., Japan Electronic Industry Development Association
    Inventors: Yuji Yokomizo, Keiji Yuuki, Naoe Watanabe
  • Patent number: 4462930
    Abstract: A humidity sensor formed of a sintered compact consisting essentially of material substantially of a spinel structure represented by the formula: M.sub.1-x A.sub.x Fe.sub.2 O.sub.4-.alpha. where M stands for magnesium or zinc, A stands for an alkali metal, x is the numerical value in the range of 0.001 to 0.2, and .alpha. is the number of oxygen vacancies. The humidity sensor is highly sensitive over a wide relative humidity range, withstands a long use and presents almost no hysteresis in its humidity-resistance characteristics.
    Type: Grant
    Filed: December 1, 1982
    Date of Patent: July 31, 1984
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Toshihiko Suzuki, Noboru Matsui
  • Patent number: 4456902
    Abstract: A gas and humidity sensing element in a single integral structure made of a base plate of apatite ceramics, on which a particular metal oxide such as tin oxide, zinc oxide, or composite oxide of titanium and niobium is provided. The sensing element has a function of sensing gas and humidity with outstanding sensitivity to bad smell gas and alcoholic gas, in which the humidity is sensed and measured by variations in electrical resistance of the apatite ceramic base plate and the bad smell gas such as hydrogen sulfide, methyl mercaptan, etc. is sensed and measured by variations in electrical resistance of the metal oxide.
    Type: Grant
    Filed: March 16, 1983
    Date of Patent: June 26, 1984
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoshiharu Komine, Takao Sawada
  • Patent number: 4450429
    Abstract: A humidity sensitive resistance device, including opposing electrodes (102, 103) formed on an insulating substrate (101), and a humidity sensitive resistance film (104) formed on the surface of the insulating substrate (101) and at least between the opposing electrodes (102, 103). The resistivity of the humidity sensitive resistance film (104) increases with an increase of an ambient relative humidity. The humidity sensitive resistance film (104) comprises a hydrophilic polymer and a conductive powder, and has a zirconium compound unevenly distributed on the side of surface thereof. The surface of the humidity sensitive resistance film (104) is dehydrated by contact with an alkaline solution or by heating.
    Type: Grant
    Filed: October 26, 1982
    Date of Patent: May 22, 1984
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Michihiro Murata
  • Patent number: 4447352
    Abstract: A humidity sensitive element, which comprises a sintered humidity sensitive resistor composed of 70 to 20 mole % of ZnFe.sub.2 O.sub.4 and 30 to 80 mole % of a member selected from the group consisting of SiO.sub.2 and MnO.sub.2 and can detect humidity as electrical signals due to the nature of the element that its electrical resistance varies with the change of the humidity to be detected.
    Type: Grant
    Filed: February 8, 1983
    Date of Patent: May 8, 1984
    Assignee: Nippondenso Co., Ltd.
    Inventors: Haruhiko Inoue, Shun-ichi Murasaki, Masataka Naito
  • Patent number: 4442422
    Abstract: A humidity sensitive resistor, comprising a pair of detecting electrodes (2) and (3) formed on an insulating substrate (1), and a humidity sensitive film (4) formed to coat on this detecting electrodes, the humidity sensitive film (4) being made of an integrated structure of a first layer macromolecular resin film (5) containing a polyvinyl alcohol polymer and an electrolyte and a second layer of hygroscopic macromolecular resin film (6) covering on the surface of the first layer, and humidity being detected with the aid of a change of the resistance value of this humidity sensitive film (4).
    Type: Grant
    Filed: March 21, 1983
    Date of Patent: April 10, 1984
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Michihiro Murata, Shoichi Kitao, Shinsei Okabe
  • Patent number: 4442421
    Abstract: A unique semiconductive, polymeric material capable of use for example as a humidity sensing detector or as an electrical "rectifying-type" element created by pressure treating an oxidized coordination polymer formed from a polydentate organic ligand, such as for example 1,2,4,5-tetraaminobenzene, and a metal salt, such as for example nickle(II) chloride, palladium(II) chloride, or platinum(II) chloride. The element is mounted on a non-conducting base, electrical leads are attached to the element, and the wired element is placed in an electrical circuit capable of for example detecting electrical resistance. The presence of water vapor in the atmosphere about the element elicits rapid, reversible, reproducible changes in the resistance of the element. The wired element can also be used as a "rectifyer-type" element in that it has an electrical polarization which is not instantaneously reversible with a change in voltage polarity.
    Type: Grant
    Filed: July 31, 1981
    Date of Patent: April 10, 1984
    Inventors: Otha J. Jacobus, Donald R. Owen
  • Patent number: 4441968
    Abstract: Electric humidity detecting sensing element on the basis of a layer of porous aluminum oxide, treated by sealing in boiling water, passivation and tempering at 70.degree. to 110.degree. C., achieving thereby a substantial reduction of subsequent variations of calibrating curves. The time of tempering may range from 2 to 24 hours. A preferred average time of tempering is 8 hours, with a practical upper limit of 12 hours.
    Type: Grant
    Filed: December 1, 1981
    Date of Patent: April 10, 1984
    Assignee: Matematicko-fyzikalni fakulta University Karlovy v Praze
    Inventors: Ivan Emmer, Zdenek Hajek, Petr Repa
  • Patent number: 4433320
    Abstract: A dew sensor comprising a substrate (1), a pair of detecting electrodes (2, 3) and a plurality of humidity sensitive members (4), the plurality of humidity sensitive members (4) connecting said opposing detecting electrodes (2, 3) on the substrate (1) and thus the detecting electrodes (2, 3) being at least in part exposed or uncovered.
    Type: Grant
    Filed: August 18, 1982
    Date of Patent: February 21, 1984
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Michihiro Murata, Akira Kumada
  • Patent number: 4424508
    Abstract: A moisture sensitive element for detecting humidity variations through sensing variations in electric resistance using a porous metal oxide ceramic. At least either phorphorus or sulfur is incorporated in and supported by the porous metal oxide ceramic with the phosphorus or sulfur being applied in either a pure or oxide form.
    Type: Grant
    Filed: August 10, 1981
    Date of Patent: January 3, 1984
    Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
    Inventors: Mituo Harata, Masaki Katsura, Shigeki Uno, Hideaki Hiraki, Masayuki Shiratori
  • Patent number: 4422129
    Abstract: A humidity sensor which varies in electrical impedance with variations in humidity in the atmosphere in which it is placed comprising a ceramic body, at least a pair of spaced electrodes disposed on said ceramic body in electrical contact therewith, and an electrical contact on each said electrode, said ceramic body being an electrolyte comprised of Na.sub.1+x Si.sub.x Zr.sub.2 P.sub.3-x O.sub.12, where x has a value ranging from 1.5 to 2.8, said ceramic body having a density of at least about 90% of the theoretical density for said Na.sub.1+x Si.sub.x Zr.sub.2 P.sub.3-x O.sub.12, each said electrode being in the form of a continuous interconnecting network which forms at least a sufficient plurality of non-linear recesses with the surface of the ceramic body exposing said ceramic body surface to said atmosphere to produce a measurable electrical impedance change when said atmosphere varies in relative humidity.
    Type: Grant
    Filed: August 19, 1982
    Date of Patent: December 20, 1983
    Assignee: General Electric Company
    Inventors: Jacqueline L. Briant, Jeffrey A. Asher
  • Patent number: 4419889
    Abstract: A moisture sensitive device is disclosed which comprises a moisture sensitive element including a material comprising a hydroxyapatite, i.e. M.sub.10 (PO.sub.4).sub.6 (OH).sub.2, wherein M is at least one member selected from the group consisting of Sr, Ca and Ba, at least two electrodes formed on the moisture sensitive element, with the electrodes being separated by the element, and electrical leads connected to each of the electrodes.
    Type: Grant
    Filed: March 27, 1981
    Date of Patent: December 13, 1983
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Katsutoshi Muto, Takao Sawada, Yoshiharu Komine
  • Patent number: 4419021
    Abstract: A multi-functional sensing and measuring system capable of detecting both temperature and humidity is fabricated from a porous metal-oxide ceramic whose dielectric constant varies with temperature and whose electric resistance varies with ambient humidity. The sensing element is connected in series with a resistor and a rectangular pulse voltage is applied across the series combination, and the ambient temperature and humidity are measured simultaneously in terms of (i) the circuit time constant (to measure temperature) of a transient state value and (ii) the steady state value of the voltage across the resistor (to measure humidity).
    Type: Grant
    Filed: January 28, 1981
    Date of Patent: December 6, 1983
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Jiro Terada, Tsuneharu Nitta
  • Patent number: 4386336
    Abstract: A humidity sensor as well as a humidity detection circuit are disclosed, the former employing a humidity sensitive material the electric resistance of which varies in response to the variance of humidity in an atmosphere and the latter employing such humidity sensitive material. The humidity sensor comprises a base plate made of alumina or the like with a humidity sensitive material formed on the base plate so as to form a film of a high molecular polymer unit which contains a reactive cationic monomer unit, is capable of detecting humidity over a wide range, shows little variance in nature in a high humidity atmosphere of organic gas, and has a long life. The humidity detection circuit comprises an oscillation circuit, a pair of electrodes which are connected by means of the humidity snesor and to one of which is supplied the output of the oscillation circuit as an input, and an amplifier circuit which is connected to the other one of the pair of electrodes.
    Type: Grant
    Filed: August 22, 1980
    Date of Patent: May 31, 1983
    Assignee: Shinyei Kaisha
    Inventors: Shinichi Kinomoto, Masato Kawamura, Susumu Kobayashi
  • Patent number: 4379406
    Abstract: Sensor and method of fabricating a sensor for detecting relative humidity with a substantially linear response from 0% to 100% and also detecting temperature. The sensor utilizes a unique essentially pure Al.sub.2 O.sub.3 layer which has a disordered crystalline structure and a density gradient which varies from a low density at its lower surface to a higher density at its upper surface which together produce the desired linear response to relative humidity.The sensor is employed as a three-terminal semiconducting device which is biased with d.c. current, allowing implementation with standard ICs and LSI circuitry. Application of a biasing current on the top electrode allows the RH sensor to be operated simultaneously as a temperature sensor.Also disclosed is a relative humidity detector system for adjusting sensitivity of the sensor for changes in environmental temperature so as to provide a true linear relative humidity response. Periodic discharge of the d.c.
    Type: Grant
    Filed: September 25, 1980
    Date of Patent: April 12, 1983
    Inventors: Paul F. Bennewitz, Matt C. Bennewitz
  • Patent number: 4378691
    Abstract: A multi-functional sensor capable of sensing the humidity and the concentration of reducing gases in the surrounding atmosphere with a single sensing element of p-type metal-oxide ceramic semiconductor is provided. When the ambient temperature is lower than 150.degree. C., the sensor can detect humidity in terms of variations in ion conduction due to the physical absorption of water by the sensing element, but when the ambient temperature or the temperature of the sensing element is at temperatures between 200.degree. and 600.degree. C., the sensor can detect the presence or concentration of reducing gases in the surrounding atmosphere in terms of variations in electron conduction due to the chemical absorption of gases by the sensing element.
    Type: Grant
    Filed: January 28, 1981
    Date of Patent: April 5, 1983
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Jiro Terada, Tsuneharu Nitta
  • Patent number: 4373391
    Abstract: A relative humidity sensitive material comprises a mixture of at least one hygroscopic salt and an at least partially electrically conductive metal based powder. Each salt in the relative humidity sensitive material has a cationic constituent selected from the group consisting of the alkali and alkaline earth metals and an anionic constituent selected from the group consisting of a chlorate, perchlorate, and chloro aluminate. The metal based powder preferably comprises a metal or metal oxide powder or powder mixture including such constituents as Zr, CO.sub.3 O.sub.4, and MnO.sub.2. Additionally, the material may include a binding agent and a slurry mixture may be formed for placement of the resultant material between electrodes on a substrate so as to form a relative humidity sensor. These sensors are employed either individually or configured in a system used to either indicate or control the relative humidity.
    Type: Grant
    Filed: April 24, 1981
    Date of Patent: February 15, 1983
    Assignee: General Electric Company
    Inventor: Peter D. Johnson
  • Patent number: 4356150
    Abstract: A conductivity type thin film humidity sensor on a silicon chip which sensor includes structure which electrically shields the sensing area from highly dissociative contaminants.
    Type: Grant
    Filed: May 15, 1981
    Date of Patent: October 26, 1982
    Assignee: Honeywell Inc.
    Inventors: Robert G. Johnson, Thomas E. Hendrickson
  • Patent number: 4343688
    Abstract: A method of making a humidity sensor which comprises an alumina substrate bearing a pair of noble metal electrodes. The electrodes are electrically connected to each other by an electrically conductive moisture-sensitive layer present on the substrate. In order to be able to monitor the moisture content of a gaseous atmosphere inside the housing of a sealed electronic device, for example an integrated circuit or an acoustic surface wave device, it is necessary to use a small sensor which can be used in a static atmosphere. According to the method, an electrode system may be formed by sputtering gold onto an alumina substrate. The substrate bearing the electrode system is then baked in air at a temperature in the range of from 100.degree. to 750.degree. C. for from 30 hours to 1/2 hour, and then a coating comprising orthophosphoric acid or phosphorus pentoxide is applied over that area of the substrate which is to bear the moisture-sensitive layer. The assembly is heated at from 50.degree. to 500.degree. C.
    Type: Grant
    Filed: November 17, 1980
    Date of Patent: August 10, 1982
    Assignee: U.S. Philips Corporation
    Inventor: Mervyn G. Harwood
  • Patent number: 4344062
    Abstract: A humidity sensor element comprising a metal oxide semiconductor sintered member having a composition composed of TiO.sub.2 and V.sub.2 O.sub.5, the member being formed with a pair of electrodes. When the element is used at a temperature of less than 400.degree. C., it is possible to detect the humidity as a variation of electric resistance.
    Type: Grant
    Filed: June 3, 1980
    Date of Patent: August 10, 1982
    Assignee: Chichibu Cement Co., Ltd.
    Inventors: Giichi Sudoh, Keiichi Minegishi, Tokuji Akiba, Tadao Kato, Norio Ogawa
  • Patent number: 4337658
    Abstract: A humidity sensor having an extended impedance range extending up to 10.sup.12 ohms precludes leakage currents. The sensor is in the form of an insulating substrate having conductive film such as gold applied to a surface thereof. The perimeter of a first film is completely encompassed by but spaced from a second film on the surface of the substrate. A humidity responsive layer of iron oxide is applied over the film layers to bridge the spacing therebetween in a continuous manner. Electrical terminals are connected, respectively, to the two films to provide a readout in terms of humidity.
    Type: Grant
    Filed: September 14, 1981
    Date of Patent: July 6, 1982
    Assignee: Honeywell Inc.
    Inventors: Curtus D. Motchenbacher, Merle E. Nicholas
  • Patent number: 4330718
    Abstract: A humidity sensor as well as a humidity detection circuit are disclosed, the former employing a humidity sensitive material the electric resistance of which varies in response to the variance of humidity in an atmosphere and the latter employing such humidity sensitive material. The humidity sensor comprises a base plate made of aluminum or the like with a humidity sensitive material formed on the base plate so as to form a film of a high molecular polymer unit which contains a reactive cationic monomer unit, is capable of detecting humidity over a wide range shows little variance in nature in a high humidity atmosphere of organic gas, and has a long life. The humidity detection circuit comprises an oscillation circuit, a pair of electrodes which are connected by means of the humidity sensor and to one of which is supplied the output of the oscillation circuit as an input, and an amplifier circuit which is connected to the other one of the pair of electrodes.
    Type: Grant
    Filed: June 20, 1979
    Date of Patent: May 18, 1982
    Assignee: Shinyei Kaisha
    Inventors: Shinichi Kinomoto, Masato Kawamura, Susumu Kobayashi
  • Patent number: 4328478
    Abstract: A humidity sensitive device comprises a base body of a preferably porous semiconductive ceramic having a grain boundary. A high resistance layer is formed in the grain boundary of the semiconductive ceramic and exhibits a humidity sensitive characteristic. First and second electrodes for withdrawing an electrical signal are formed spaced from each other on at least one major surface of the semiconductive ceramic base.
    Type: Grant
    Filed: September 8, 1980
    Date of Patent: May 4, 1982
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Michihiro Murata, Shinsei Okabe
  • Patent number: 4326414
    Abstract: A humidity detecting resistor porcelain element, with at least one portion of an electrode being made of a resistance heating unit and the electrode serving for the resistance heating unit and humidity detecting element, and a humidity detecting apparatus using the humidity detecting resistor porcelain element. The heating and cleaning operations of the humidity detecting resistor porcelain can be uniformly and efficiently performed, thus ensuring the stable humidity detection. Also, the circuit construction of the humidity detecting apparatus can be simplified. They can be provided for use in the detecting and controlling operations of the various humidities.
    Type: Grant
    Filed: December 26, 1979
    Date of Patent: April 27, 1982
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Jiro Terada, Tsuneharu Nitta
  • Patent number: 4321577
    Abstract: A humidity sensitive device is formed of a humidity sensitive material comprised of a magnesium aluminate spinel and titania material. The humidity sensitive device includes various means for applying heat to the humidity sensitive material to purge the humidity sensitive material of foreign substances and also thereby to restore or rejuvenate the characteristics of the humidity sensitive material.
    Type: Grant
    Filed: February 25, 1980
    Date of Patent: March 23, 1982
    Assignee: General Electric Company
    Inventor: Richard O. Carlson
  • Patent number: 4319485
    Abstract: A temperature.multidot.humidity detecting apparatus which can detect the temperature and humidity with a single element. The temperature.multidot.humidity detecting element of the present invention varies its impedance value with respect to variations in the temperature and humidity, and the temperature.multidot.humidity detecting apparatus is adapted to detect the variations in the temperature.multidot.humidity detecting element impedance to determine the temperature and humidity.
    Type: Grant
    Filed: December 26, 1979
    Date of Patent: March 16, 1982
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Jiro Terada, Tsuneharu Nitta
  • Patent number: 4298855
    Abstract: A humidity sensor utilizes a conductive polymer film that normally exhibits a variable resistance characteristic. The polymer film also exhibits a humidity responsive function that can be utilized while the temperature responsive function is balanced out. The device is capable of a high level of calibration by the use of laser trimming of the conductive polymer film resistors.
    Type: Grant
    Filed: August 26, 1980
    Date of Patent: November 3, 1981
    Assignee: Honeywell Inc.
    Inventor: Frank S. Mills
  • Patent number: 4288775
    Abstract: Sensor and method of fabricating a sensor for detecting relative humidity with a substantially linear response from 0% to 100% and also detecting temperature. The sensor utilizes a unique essentially pure Al.sub.2 0.sub.3 layer which has a disordered crystalline structure and a density gradient which varies from a low density at its lower surface to a higher density at its upper surface which together produce the desired linear response to relative humidity. The method of producing the unique essentially pure Al.sub.2 O.sub.3 layer includes anodizing with an ac current in a solution of approximately 6.4 normal acid at a starting temperature of 21.degree. C. and allowing the temperature of the anodizing solution to rise with the process to vary the density of the Al.sub.2 O.sub.3 layer. The Al.sub.2 O.sub.3 layer is neutralized in a base solution, washed in boiling water and alcohol to neutralize the Al.sub.2 O.sub.3 layer and remove impurities.
    Type: Grant
    Filed: November 9, 1979
    Date of Patent: September 8, 1981
    Inventors: Paul F. Bennewitz, Matt C. Bennewitz
  • Patent number: 4280115
    Abstract: A humidity sensor which responds to changes in atmospheric water content by changes in sensor impedance, has a non-porous, water impervious, ionic-conductive beta-alumina substrate, a pair of spaced apart, thin electrodes mounted on at least one major surface of the substrate, and an electrical lead in contact with each of the electrodes.
    Type: Grant
    Filed: June 18, 1979
    Date of Patent: July 21, 1981
    Assignee: General Electric Company
    Inventor: Gregory C. Farrington
  • Patent number: 4276537
    Abstract: A moisture-responsive resistor element comprising, as a moisture-responsive resistance material, metastannic acid alone or in combination with tin dioxide.
    Type: Grant
    Filed: December 18, 1979
    Date of Patent: June 30, 1981
    Assignee: Sanyo Silicon Electronics Co., Ltd.
    Inventor: Hiroshi Shimizu
  • Patent number: 4272986
    Abstract: The moisture content of a hermetically sealed semiconductor device is a function of the dew point of the cavity atmosphere which is the temperature of maximum surface conductivity. A pattern of interdigitated thin film aluminum conductors is provided on an impurity free, non-porous silicon oxide insulative substrate. The surface conductivity of this structure rises as moisture condenses onto and between the conductors as the temperature is reduced at a slow controlled rate to the dew point temperature. The amplitude of the maximum surface conductivity is proportional to ionic impurity concentration.
    Type: Grant
    Filed: April 16, 1979
    Date of Patent: June 16, 1981
    Assignee: Harris Corporation
    Inventors: Robert K. Lowry, Larry A. Miller
  • Patent number: 4263576
    Abstract: A humidity sensitive device, including opposing electrodes formed on an insulating substrate, and a humidity sensitive film formed on the surface of the insulating substrate and at least between the opposing electrodes. The humidity sensitive film is obtained by coating on the surface of the insulating substrate a uniformly dispersed mixture including zirconium oxychloride and epoxy resin and heating the same.
    Type: Grant
    Filed: June 27, 1979
    Date of Patent: April 21, 1981
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Michihiro Murata, Shinsei Okabe
  • Patent number: 4245506
    Abstract: An improved sensor which responds to varying relative humidity by a change in impedance does not fail at 95-100 percent relative humidity. A microporous glass membrane or irradiated-and-etched plastic membrane contains a salt in its pores and has conductive coatings on both surfaces and hydrophobic films on the conductive coatings. At high humidities the pore fills with water and forms a bulge on the end of the pore because water will not wet the hydrophobic film. With proper choice of the pore radius no salt solution spills out.
    Type: Grant
    Filed: September 19, 1979
    Date of Patent: January 20, 1981
    Assignee: General Electric Company
    Inventor: William H. Meiklejohn
  • Patent number: 4227411
    Abstract: A relative humidity measuring instrument includes two spaced electrodes on an insulating substrate which is mounted on a Peltier-effect thermoelectric module. When the substrate is cooled by the thermoelectric module, a comparator connected to the electrodes on the substrate detects a decrease in resistance between said electrodes due to condensation of moisture therebetween. Then a microcomputer receptive to temperature signals from a thermometer on the substrate and an ambient thermometer computes the relative humidity.
    Type: Grant
    Filed: September 24, 1979
    Date of Patent: October 14, 1980
    Assignee: RCA Corporation
    Inventor: Abe Abramovich
  • Patent number: 4224565
    Abstract: A moisture sensing unit (30, FIG. 1 or 58, FIG. 4) is included within a hermetically sealed package. A localized external portion of the package in close proximity to the unit is cooled while the temperature and the alternating-current capacitance and/or conductance characteristic of the unit are measured. The measured characteristic exhibits a sharp increase at the temperature corresponding to the dew point of the atmosphere within the package. In turn, the dew point temperature is a direct indicator of the moisture content of the package.
    Type: Grant
    Filed: June 5, 1978
    Date of Patent: September 23, 1980
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventors: Jacob Sosniak, Burton A. Unger
  • Patent number: 4210894
    Abstract: The present invention is an electrical terminal unit adapted for supporting an electrical circuit element, for example, a moisture responsive resistor or the like and a sensing device employing this terminal unit. The terminal unit makes the influence of the reduction in insulation resistance between the terminals due to adhesion of pollutants to the terminal unit negligible by providing a grounded electrically conductive member or electrode member between the conductive terminal leads extending through a base or substrate of the terminal unit for electrically separating these terminal leads.
    Type: Grant
    Filed: August 29, 1978
    Date of Patent: July 1, 1980
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Tsuneharu Nitta, Ziro Terada, Shigeru Hayakawa
  • Patent number: 4203087
    Abstract: Disclosed are humidity sensor structures, and fabrication techniques, which result in uniform and reliable humidity sensing, reliable electrical connections in small sensors, and simplified and inexpensive manufacture.
    Type: Grant
    Filed: November 20, 1978
    Date of Patent: May 13, 1980
    Assignee: Panametrics, Inc.
    Inventors: Michael G. Kovac, David J. Chleck, Philip Goodman
  • Patent number: 4196338
    Abstract: A humidity-responsive heating circuit for a window of an automotive vehicle includes a grid of heating conductors on the window and two conductors closely approaching each other on the surface of the window such that the resistance between them changes, upon the appearance of humidity bridging the space between them, sufficiently to provide a signal. All of the conductors are composed of the same paste having the same properties and are applied as a single baked, silk screen printed pattern. The circuit may further include a switch to apply a voltage between those two conductors, amplifying means responsive to change of resistance between them, and a relay controlled by the amplifying means for connection of the heating grid to a source of voltage.
    Type: Grant
    Filed: August 11, 1977
    Date of Patent: April 1, 1980
    Assignee: Saint-Gobain Industries
    Inventor: Hans D. Edel
  • Patent number: 4189330
    Abstract: The transfer elements of a heat and humidity exchanger are made by forming the transfer elements in the desired configuration and of a non-hygroscopic metal such as aluminum, and treating the surfaces to produce an integral hygroscopic layer thereof. This is done by oxidizing the surface of the metal to form an oxide layer, which itself is hygroscopic, and preferably enhancing the hygroscopic properties by subsequent impregnation of the oxide with a hygroscopic material such as lithium chloride. According to one form of the method, the oxidizing layer is produced by immersing the transfer elements, in a bath such as a warm aqueous solution of sodium hydroxide, or sodium carbonate, followed by heating in humid air; in a second form of the method, the oxide layer is produced by heating in humid air, or in a water, without preliminary alkaline treatment; in a third form of the method, the oxide layer is formed in a water bath containing an oxidizing agent such as trietanolamin or hydrogen peroxide.
    Type: Grant
    Filed: April 20, 1977
    Date of Patent: February 19, 1980
    Assignee: AB Svenska Flaktfabriken
    Inventors: Ove Strindehag, Erik Wrangel
  • Patent number: 4167725
    Abstract: A dew-sensing hygroscopic element includes a pair of electrodes and a dew-sensing hygroscopic material arranged between the electrodes which detects dew by the change of impedance between the electrodes. The dew-sensing hygroscopic material comprises polyvinyl alcohol having a saponification equivalent of 20 to 65 as a base material and contains an organic electrolyte.
    Type: Grant
    Filed: August 4, 1977
    Date of Patent: September 11, 1979
    Assignee: Sony Corporation
    Inventors: Hidetoshi Shimizu, Hidemasa Tamura, Yoshimi Makino
  • Patent number: 4143177
    Abstract: Disclosed are humidity sensor structures, and fabrication techniques, which result in uniform and reliable humidity sensing, reliable electrical connections in small sensors, and simplified and inexpensive manufacture.
    Type: Grant
    Filed: January 31, 1977
    Date of Patent: March 6, 1979
    Assignee: Panametrics, Inc.
    Inventors: Michael G. Kovac, David J. Chleck, Philip Goodman
  • Patent number: 4140990
    Abstract: A probe for selectively detecting a vapor component in a gaseous atmosphere in contact therewith. The probe includes a pair of measuring electrodes and a semiconductor layer which is coated with a dielectric layer. An auxiliary electrode is placed opposite the semiconductor layer so that the voltage can be varied and consequently the level of the average current can be adjusted. It is thereby possible to detect the concentration of a vapor component to be measured in the entire range and with the same sensitivity.
    Type: Grant
    Filed: February 10, 1977
    Date of Patent: February 20, 1979
    Assignee: U.S. Philips Corporation
    Inventor: Jean Pompei Katz de Warrens