Abstract: An organic chemical sensor includes a dielectric core that comprises an elastomer and a high dielectric constant material. The elastomer absorbs an organic chemical to be sensed. An electrically conductive layer is secured to a first side of the dielectric core. A permeable conductive layer is secured to a second side of the dielectric core. The permeable conductive layer is electrically conductive and permeable to the organic chemical to be sensed. The absorption of the organic chemical to be sensed by the elastomeric layer causes a decrease in the capacitance between the electrically conductive layer and the permeable conductive layer.

Abstract: An organic chemical sensor includes a dielectric core that comprises an elastomer and a high dielectric constant material. The elastomer absorbs an organic chemical to be sensed. An electrically conductive layer is secured to a first side of the dielectric core. A permeable conductive layer is secured to a second side of the dielectric core. The permeable conductive layer is electrically conductive and permeable to the organic chemical to be sensed. The absorption of the organic chemical to be sensed by the elastomeric layer causes a decrease in the capacitance between the electrically conductive layer and the permeable conductive layer.

Abstract: A capacitance elastomeric pressure sensor includes top and bottom mounting plates arranged to support a pair of electrode layers. The first electrode layer is supported on the upper surface of a dielectric disc held by an upper mounting plate. The second electrode layer is located beneath the disc and includes a conductive elastomeric layer overlying an elastomeric support layer. In the preferred embodiment, the elastomer is a silicone elastomer and the conductive layer is formed by admixing a conductive carbon powder with the silicone. The sensor is particularly effective in sensing pressure changes in this low range, e.g. 0-1 inch of water. In the most preferred embodiment the elastomeric layer is prestrained for temperature compensation.

Abstract: A capacitance humidity sensor according to the invention has a dielectric film core which is in contact with a pair of polymeric conductive layers bonded to opposite faces of the core. The dielectric core is made of a polymeric material having a dielectric constant which varies substantially linearly with humidity, such as a polyimide or polyparabanic acid. The conductive layers are made of a polymeric material having conductive particles, such as carbon particles, dispersed therein. Such conductive layers provide superior performance and corrosion resistance in comparison to the metal films commonly employed in the prior art.

Abstract: In general and in one preferred method, a diaphragm plate may be formed by providing a vessel containing a quantity of a light-transmittive first photopolymer compound which includes, as mixed constituents, a reactive oligomer resin, a reactive monomer diluent and a photoinitiator. A first unmasked surface of the compound is irradiated with ultraviolet (UV) light for solidifying the surface to a depth equal to the relief thickness, i.e., the desired diaphragm thickness. A second surface of the compound is irradiated with UV light subsequent to being covered with a opaque mask which defines the shape of the diaphragm. This irradiation completes the formation of the diaphragm plate by solidifying the remaining, unmasked quantity of compound. The unsolidified compound is then removed from the masked area of the plate. Other preferred methods are also disclosed.

Abstract: A sensor chip subassembly for use in a transducer assembly includes a support member to which a pressure sensitive chip is elastically bonded at predetermined but spaced points to separate the chip from direct contact with the support member. The separation minimizes vibration and stress from being transmitted from the support member to the chip.

Abstract: A printed circuit board with electronic components wired thereto has a conformal insulating coating consisting of a single component of essentially pure urethane formulation and a minor amount of fumed colloidal silica powder. The insulating coating covers asperities and protrusions as well as the conductors and circuit components while maintaining a transparent characteristic. The coating material is made by mixing of the small proportion of silica with essentially pure urethane formulation under controlled conditions to prevent moisture contamination of the materials. The mixture is thoroughly mixed, deaerated under reduced pressure with a pulsating pressure to break any air bubbles and remove essentially all air. The coating is applied in an environment having at least 30 percent relative humidity and within a confined area defined by an encircling dam masking compound. The coating is allowed to partially cure at room temperature and the confining dam compound removed.

Abstract: A method of making an element for sensing the presence of nitrogen dioxide gas in the environment. The element is formed by heating a film of an electrically non-conductive polyaromatic polymer to a temperature sufficiently high to pyrolyze the polymer and render the polymer semi-conductive. The pyrolyzed film is mounted on an electrically non-conductive base. Electrical leads are attached at spaced locations to the film and are connected in an electrical circuit with a signalling or control mechanism. The presence of nitrogen dioxide gas will cause a change in the electrical characteristics of the film to thereby activate the mechanism. A heating element can be associated with the base to insure constant temperature and humidity conditions.

Abstract: A temperature sensitive thick film resistor unit for use in detecting and control systems is formed employing thick film plating technology. A final sized negative is formed from enlarged artwork and transferred to a photosensitive emulsion supported on a stainless steel screen to form a printing stencil. A fritted molecular bonding nickel paste including finely divided vitreous and nickel particles in a solvent carrier is screen printed onto an alumina substrate by a pressure printer in which the paste is forced through the screen to control the thickness of the deposited nickel paste. The deposited nickel is allowed to settle and partially heated to remove gases and organic solvents. A highly conductive film is overlaid on tab connecting ends and the unit is fired to intimately attach the nickel paste to the substrate by the formation of a chemical bond.

Abstract: An element for sensing the presence of nitrogen dioxide gas in the environment. The element comprises a film of a pyrolyzed polyaromatic polymer having semi-conductive properties which is mounted on an electrically non-conductive base. Electrical leads are attached at spaced locations to the film and are connected in an electrical circuit with a signalling or control mechanism. The presence of nitrogen dioxide gas will cause a change in the electrical characteristics of the film to thereby activate the mechanism. A heating element can be associated with the base to insure constant temperature and humidity conditions.