Abstract: A lithium ion sensor includes a FET, a redox layer having a redox function covering a gate isolating membrance of the FET, and a lithium ion-sensitive layer selectively sensing lithium ion covering the redox layer.

Abstract: A film-coated sensor is formed by providing an electrically conductive substrate (2), which has a sectional area of less than 10.sup.-5 cm.sup.2, connected to a lead wire (5) at one end of an insulative capillary (1) and inscribed in the capillary (1), and providing a coating film (7) at another end, which is open, of the capillary (1) by an electrolytic polymerization process.The film-coated sensor obtained has a surface which is uniform, the film coating is easy to control, and since the sensor is not readily susceptible to flow of a specimen fluid, there is little drift and response is quick. Owing to its small size, the sensor is capable of measuring very small samples and of performing measurement upon being directly inserted into a living body or tissue.The sensor can be used also as an enzyme sensor by coating the surface of the film-coated sensor with a fixing enzyme film.

Abstract: A portion of a board (1) on which copper wiring is printed is provided with a carbon coating, the board (1) and lead wires (2) are joined by solder (3), the portion having the solder (3) is insulated with a silicone resin (4), and the carbon-coated printed wiring portion (10a) is successively coated with a redox layer (11) obtained by electro-oxidation of 2,6 xylenol and an ion-selective layer (12), thereby forming an ion sensor (20).Since the ion sensor can be formed on a printed wiring board, various devices which include an ion sensor can readily be fabricated on a board.

Abstract: An ion sensor of the type wherein a specific type of ion in an aqueous solution is measured by potential response. The sensor includes a conductor base, and a reversible redox polymer film formed directly on a surface of said conductor base. An ion carrier film is formed directly on a surface of said redox polymer film. The carrier film contains an ion carrier substance for allowing the specific type of ions to permeate from the aqueous solution to said polymer film.

Abstract: The surface of an electrically conductive substrate (1) is provided with a redox layer (5) by an electrolytic polymerization process, and the surface of the resulting member is further provided with an ion carrier membrane (6) which includes polyvinyl chloride, a plasticizer and an ion carrier, thereby forming an ion sensor. Used as the plasticizer is one selected from among phthalate plasticizers, maleate plasticizers, adipate plasticizers, carboxylate plasticizers and polycaprolactone plasticizers, or one selected from among plasticizers comprising modified ethylene-- vinyl acetate copolymer. The ion sensor obtained has low solubility in the plasticizer of the redox layer and therefore is highly stable. Since the ion sensor has little toxicity, it can be used in vivo.

Abstract: A reference electrode for generating a reference potential on an ion sensor is disclosed. The reference electrode has a lamination film covering a surface of an electrically conductive substrate and formed by alternately laminating silver halide thin films and hydrophobic resin thin films.

Abstract: The surface of a gate insulating membrane of an ion-selective field-effect transistor (ISFET) (10) is coated with a carbon thin membrane (4), and the surface of the latter is coated with an electrolytic polmerization membrane (3) of 2,6 xylenol. The ISFET obtained exhibits hydrogen-ion selectivity, little drift, high stability and little response to light. If the surface of the electrolytic polmerization membrane (3) of 2,6 xylenol is coated with another ion-selective membrane or enzyme-active membrane, various ions and the concentration of a biological substrate can be measured.

Abstract: The surface of an electrically conductive substrate (1) is provided with a redox layer (5) by an electrolytic polymerization process, and the surface of the resulting member is further provided with an ion carrier membrane (6) which includes polyvinyl chloride, a plasticizer and an ion carrier, thereby forming an ion sensor. Used as the plasticizer is one selected from among phthalate plasticizers, maleate plasticizers, adipate plasticizers, carboxylate plasticizers and polycaprolactone plasticizers, or one selected from among plasticizers comprising modified ethylene - vinyl acetate copolymer. The ion sensor obtained has low solubility in the plasticizer of the redox layer and therefore is highly stable. Since the ion sensor has little toxicity, it can be used in vivo. A preferred plasticizer is benzopohenon-tetracarboxylic under cyclic acid.

Abstract: Disclosed is an enzyme sensor for measuring a predetermined substrate concentration by potentiometric or amperometric response on the basis of an enzyme. In one aspect, a solid-state enzyme sensor measures a predetermined substrate concentration by potentiometric response and includes a solid enzyme membrane-coated electrically conductive base, redox layer or ion-sensitive layer. In another aspect, a solid-state enzyme sensor measures a predetermined substrate concentration by amperometric response and includes a solid enzyme membrane-coated oxygen reduction catalyst layer. Also disclosed is an enzyme control layer for controlling the outflow and inflow of the enzyme layer.

Abstract: An ion-sensitive FET sensor has a MOSFET gate isolating membrane whose surface is covered by an ion-sensitive layer. A redox layer having a redox function is provided between the isolating membrane and the ion-sensitive layer to improve operating stability and speed of response. An electrically conductive layer or a combination of a thin metal film and an electrically conductive layer is provided between the isolating membrane and the redox layer to further improve operating stability, the adhesion of the layers and the durability of the sensor. Also disclosed are optimum materials for use as an ion carrier employed in the ion-sensitive layer.

Abstract: An optical dust detector assembly includes an air duct member having an introductory portion and a base portion for permitting a flow of air passing therethrough, the duct member having a pair of radial holes formed in its peripheral wall, a pair of cylindrical casings secured to the peripheral wall of the duct member at both sides thereof and having respective opening ends communicating with the interior of the duct member through the respective radial holes thereof, a light emission element arranged within one of the casings to emit a light beam and pass it through the radial holes toward the other casing, and a light receiving element arranged within the other casing to receive the light beam emitted from the light emission element and passed through the radial holes.

Abstract: A pH sensor includes a substrate formed of an electrically conductive carbon material. A hydrogen ion-sensitive layer is formed on the substrate surface. The layer is formed of an electrooxidation polymer of a nitrogen-containing aromatic compound selected from the group consisting of 1-aminopyrene and a mixture of 1-aminopyrene and pyridine.

Abstract: A selectively permeable film directly applied to coat the surface of an electroconductive element, said electively permeable film comprising a polymer which is derived from at least one aromatic compound selected from the group of nitrogen-containing aromatic compounds or from the group of hydroxy aromatic compounds. The nitrogen-containing aromatic compounds are aniline, 2-aminobenzotrifluoride, 2-aminopyridine, 2,3-diaminopyridine, 4,4'-diaminodiphenyl ether, 4,4'-methylenedianiline, tyramine, N-(o-hydroxybenzyl)-aniline and pyrrole. The film coated on the electrode surfaces permits selective passage of ions and the electrode can be used as an ions sensor for measuring the concentration of ions in solutions.

Abstract: A reference electrode is prepared by coating the surface of a conductive substrate with a silver complex polymer compound, which is either a compound prepared by the complex formation between a polymer compound containing a coordination nitrogen atom and a silver ion or an aforementioned complex compound containing a silver halide. This reference electrode can be used by a combination with ion sensor, a pH sensor and so on.