Abstract: An electrically heated window for a vehicle includes a transparent sheet, a plurality of electrical resistance strips disposed on the sheet, and at least two closely spaced electrodes disposed on a surface of the sheet for detection of humidity on the surface of the sheet between them. The electrodes extend along the maximum slope of the window, and may extend downwardly unequal distances.

Abstract: The glass pane of a vehicle window is provided on the surface of its central viewing area with a plurality of spaced, parallel linear heating resistors. First and second buses, disposed laterally of the central viewing area, extend transversely of the resistors and supply electric power thereto. A pair of moisture sensing, electrically conductive probes are provided on the pane at widely spaced zones away from the central viewing area. Each probe includes a first portion coextensive in length with a resistor and running parallel thereto. At least one of the probes has a second portion running parallel to one of the buses.

Abstract: A window has a heating grid and a moisture sensor formed thereon for connection to a detector which automatically controls the heating. The sensor has an output terminal and another terminal connected to a heating conductor, the sensor being positioned outwardly of the heating grid with the area of the sensor including the output terminal lying in the heating zone. Advantageously the outer limit of the sensor is closely adjacent the outer limit of the heating zone. The output terminal is positioned between the outward limit of the sensor electrodes and the boundary heating conductor. A shield electrode connected to the heating conductor may be provided. The sensor may be located between a pair of heating conductors adjacent a heating grid collector with one electrode connected to the conductors. For deep windows, the sensor may be located in an offset branched section of a boundary heating conductor.

Abstract: Apparatus and system for monitoring sites for the presence of moisture or the collection of conductive liquids. Two housings are utilized with the apparatus to facilitate user convenience. A first of these housings, mounted at a location selected for easy access by the user, retains manually actuated switching, alarm components and batteries. This housing is electrically coupled with a second, smaller housing serving to encapsulate solid-state switching logic components and moisture detecting probes. Spurious R.F. noise is avoided within the system through the positioning of this solid state switching at the second housing in close adjacency with the probes. The probes are formed of a base material, one surface portion of which is covered with a noble metal, such as platinum. The remaining surfaces of the base are permitted to develop, in situ, a surface oxide which is immune to galvanic corrosive participation.

Abstract: There is provided a humidity sensitive ceramic resistor having high humidity activity, low electrical resistance, quick response rate to humidity and high stability with respect to time, temperature, humidity and electric load which is suited for humidity-controlling devices. The ceramic resistor comprises a ceramic composition comprising at least one component having a spinel type cubic symmetry selected from the group consisting of MgCr.sub.2 O.sub.4, FeCr.sub.2 O.sub.4, NiCr.sub.2 O.sub.4, CoCr.sub.2 O.sub.4, MnCr.sub.2 O.sub.4, CuCr.sub.2 O.sub.4, Mg.sub.2 TiO.sub.4, Zn.sub.2 TiO.sub.4, Mg.sub.2 SnO.sub.4 and Zn.sub.2 SnO.sub.4, and , if desired, at least one component selected from the group consisting of TiO.sub.2, ZrO.sub.2, HfO.sub.2 and SnO.sub.2.

Abstract: An electric hygrometer wherein a body of viscous hygroscopic electrolyte is supported exclusively by two or more spaced-apart carriers so that the electrolyte contacts the gaseous medium whose relative humidity requires determination and is in conductive contact with two conductors. The impedance between the conductors varies with relative humidity of the medium. The carriers may consist of conductive and/or insulating material; in each instance, the carriers may constitute spheres, straight wires, U-shaped or V-shaped wires, loops, open or closed rings or other configurations. If the electrolyte is supported by two carriers only and the carriers consist of conductive material, each carrier is integral with one of the conductors and those portions of the carriers which contact the electrolyte constitute two electrodes which are conductively connected with the respective conductors.

Abstract: A humidity sensitive resistor device for sensing the humidity of an ambient atmosphere. The device has a humidity sensitive resistor formed by a metal oxide sintered substrate having electrodes on one surface thereof, the resistivity of the humidity sensitive resistor decreasing as the ambient humidity which can affect the surface of the humidity sensitive resistor increases; and a heater positioned near the humidity sensitive resistor for applying radiant heat to the surface of the humidity sensitive resistor, which heater can be used for improving the sensitivity of the humidity sensitive resistor. By the application of a slight amount of radiant heat, the humidity sensitivity increases, and by the application of a large amount of strong heat, stains which may be on the surface of the humidity sensitive resistor such as oil can be cleaned off so as to recover the sensitivity of the humidity sensitive resistor which might have been deteriorated by the stain.

Abstract: A humidity sensor comprising a pair of spaced electrodes on an insulating substrate is formed by coating an orthophosphate as a sensitive membrane over at least a portion of the gap between the electrodes.

Abstract: A novel humidity sensor printed and fired on a dielectric substrate comprising an interdigitated pattern of a conductive precious metal with cobalt oxide as the only binder. Sensors according to the invention may be employed as hermeticity detectors in semiconductor packages.

Abstract: The glass pane of a vehicle window is provided on the surface of its central viewing area with a plurality of spaced, parallel linear heating resistors. First and second buses, disposed laterally of the central viewing area, extend transversely of the resistors and supply electric power to the resistors. A miniature transistorized control circuit mounted at a corner of the pane away from the central viewing area controls the supply of power to the buses. A plurality of moisture sensing, electrically conductive probes are provided on the pane at widely spaced zones and are connected to the input terminal means of the control circuit. Each probe includes a first portion coextensive in length with a resistor and running parallel thereto. One of the probes has a second portion parallel to and closely spaced from one of the buses. The control circuit responds to detection of fogging of the pane by anyone of the probes.

Abstract: This invention provides a humidity sensor having a negative coefficient of resistivity for relative humidity, which comprises 99.99 to 10 mole percent of iron oxide (Fe.sub.2 O.sub.3) and 0.01 to 90 mole percent of at least one member selected from alkali metal oxides, which are lithium oxide (Li.sub.2 O), sodium oxide (Na.sub.2 O), potassium oxide (K.sub.2 O) and cesium oxide (Cs.sub.2 O). The amount of the alkali metal oxide in the sensor is preferably 0.01 to 25 mole percent. This sensor is advantageous because it can accurately detect the changes in humidity and it has a long, stable life.

Abstract: Probe for selectively detecting polar molecules in a gaseous atmosphere in contact with the probe, characterized by a layer of semiconductor material covered by a film of dielectric material.

Abstract: The invention concerns a humidity or moisture sensor, with a relatively thick sensitive monolithic ceramic volume. The sensitive volume is defined by a porous ceramic material with multiple electrodes buried therein in parallel planes which extend substantially entirely across two dimensions of the structure. Moisture entering the porous crystalline matrix is subjected to a high electric field giving rise to a current which is a function of the ambient moisture. By virtue of the inert ceramic surface and the buried precious metal electrodes, the device is sensitive, fast, yet electrically, chemically, thermally and mechanically stable.

Abstract: A novel humidity sensor printed and fired on a dielectric substrate comprising an interdigitated pattern of a conductive precious metal with cobalt oxide as the only binder. Sensors according to the invention may be employed as hermeticity detectors in semiconductor packages.

Abstract: Humidity sensitive ceramic resistor having a high humidity activity, a low electrical resistance and a high stability with respect to time, temperature, humidity and electric load and suited for use in humidity-controlling devices is provided by a sintered mixture of a main component, which consists essentially of chromium oxide and at least one metal oxide selected from the group consisting of TiO.sub.2, ZrO.sub.2, HfO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, WO.sub.3, MnO.sub.2, MoO.sub.2, CeO.sub.2, DyO.sub.2, VO.sub.2, SiO.sub.2 and GeO.sub.2, and an addition of at least one metal oxide selected from the group consisting of BeO, MgO, CaO, SrO, BaO, FeO, NiO, CuO, ZnO, CdO and PbO. Furthermore, humidity sensitive thin layer ceramic resistor having an improved quick response to humidity is obtained by sintering a mixture having the above composition with a glass frit binder.

Abstract: A low-cost fluid sensor which has a controlled resistance value is provided by depositing a resistance material between two electrodes on a portion of a molecular sieve layer. A heating resistor for drying out the fluid sensor may also be provided by depositing a resistance strip over another portion of the molecular sieve layer, or alternately by providing the resistance strip adjacent the molecular sieve layer on a supporting substrate.

Abstract: An electrically heated window for a vehicle includes a smooth surfaced transparent sheet having a plurality of spaced electric resistance heating conductors on the surface thereof. A humidity detector is provided on the inside surface of the sheet and includes two sets of conductors standing in relief above the surface of the sheet and each having substantially the shape of a comb with the teeth of the two combs interdigitated and extending substantially in the direction of maximum slope of the sheet. The back of the upper comb defines a gutter for the diversion of water droplets from the area occupied by the teeth of the combs.

Abstract: A relative humidity detector, is formed upon a substrate such as glass or amorphous quartz. An aluminum layer evaporated onto the substrate has a layer of Al.sub.2 O.sub.3 anodized thereover to a thickness of 5,000 to 10,000 angstroms. A gold upper metallic layer overlies an adherent layer of chromium upon the Al.sub.2 O.sub.3 to a combined thickness of 1000 Angstroms. After the substrate has been mounted onto an appropriate header, it is submerged in a water bath for about 8 to 12 hours. It is then heated at a temperature of about 120.degree. C. for 6 to 12 hours. The submersion and heating process produces an impedance variation at 1000 Hz which is linear over the relative humidity range of between zero and 100%.In another embodiment, an electrode of gold over chromium evaporated onto a portion of the substrate forms a first electrode. A layer of aluminum evaporated over the substrate and a portion of the first electrode has a layer of Al.sub.2 O.sub.3 thereover.

Abstract: A humidity-sensitive sensor, especially useful on the window of an automobile with the sensor on the inside surface of the glass. The sensor has a pair of spaced electrodes and a humidity-sensitive coating composed of a hydroscopic resin extending over the pair of electrodes. The resin can be an acrylate resin or a methacrylate resin, and preferably is a resin which has a volume change of at least 10% in response to a 50% change in humidity. Dispersed in the resin are electrically conductive particles, preferably in an amount of from 20 to 60% by volume of the amount of resin. The sensor, prior to its use in an operating device, is preferably exposed to a high humidity condition and a low humidity condition at least thirty times in order to stabilize it.

Abstract: The operation of relative humidity sensors made from cobalt oxide on a non-conductive ceramic substrate is improved by (1) providing a porous, sputtered overcoat of polytetrafluoroethylene which renders the sensor surface non-wettable without affecting other properties, and (2) providing a printed heating element on the back surface of the sensor, enabling in situ degassing of chemisorbed or adsorbed impurities and regeneration of a nascent sensor surface.

Abstract: Ion implanted resistor having a semiconductor body of one conductivity type and having a planar surface with a region of opposite conductivity type formed in the semiconductor body which is defined by a PN junction extending to the surface. One portion of the region of opposite conductivity type in cross-section has a greater depth than the remaining portion whereby there is provided a resistance whose effective value is the value given by the parallel resistance of said one portion and the remaining portion to thereby provide a resistor having a controlled temperature coefficient.

Abstract: A refrigeration system having an improved defrost control including a thermal relay, a bimetal thermostat, and a thick film/hybrid microelectronic element responsive to cumulative humidity of the refrigerated air comprising a moisture sensor/cumulator portion and a control circuit portion on a ceramic substrate. The sensor/cumulator absorbs water vapor at a rate proportional to the relative humidity of the refrigerated air and activates a heater element of the thermal relay to initiate a defrost period. The element is reset by thermally removing a preselected amount of the absorbed water vapor. The defrost period is terminated by a bimetal thermostat. Alternatively, a thermal responsive resistor may be included in the control circuit to terminate the defrost period.

Abstract: The operation of relative humidity sensors made from cobalt oxide on a non-conductive ceramic substrate is improved by heating the sensor for a short period to a high temperature in a reducing atmosphere. This reduces the specific resistance of the device. With a lower resistivity, it is possible to reduce the size of the sensor to the point where it can be included along with a semiconductive device in standard hermetic packages. This makes possible the continuous, one-line monitoring of hermeticity for the life of the circuit without the necessity fo applying a load to the circuit.

Abstract: The invention relates to a low-inertia hygrometer for controlling and measuring the hygrometric degree of a gaseous flux. The hygrometer includes two electrodes placed at a certain distance from one another and separated by a medium which, initially, is a poor conductor of electricity, but becomes electrically conductive when water vapour is present.