Abstract: An electrochemical element comprising a laminar structure which includes a porous first layer of fully-stabilized zirconia ceramic, a second layer of partially-stabilized zirconia ceramic, and at least one pair of electrodes. At least one of the at least one pair of electrodes is disposed between the first and second layers, and in contact with the first layer.

Abstract: An electrochemical device such as an oxygen sensor comprising: a plurality of solid electrolyte bodies; at least one pair of electrodes, each pair being disposed such that the electrodes are held in contact with the solid electrolyte bodies separately; at least one conductor sandwiched by two adjacent conductors of the solid electrolyte bodies; and at least one electrical insulation layer. A substantive portion of at least one side of the conductor indirectly contacts one of the two adjacent solid electrolyte bodies via the electrical insulation layer which is disposed therebetween, whereby the conductor is protected from direct contact with the associated solid electrolyte body. The insulation layer further serves to prevent noises which could otherwise be produced due to leakage current from the conductor. The conductor may be a lead connected to one of the electrodes, or to a heater for heating a portion of the solid electrolyte body adjacent the electrodes.

Abstract: An optical unit as used for an optical sensor, including a substrate, one or more optical elements fixedly supported by the substrate, and an protecting arrangement associated with the substrate and at least one of the optical elements, for protecting each associated optical element from thermal stresses exerted thereto due to a difference in thermal expansion coefficient between the substrate and the associated optical element. The protecting arrangement may consist of at least one intermediate body interposed between the substrate and the associated optical element. Each intermediate body has a thermal expansion coefficient close to that of the associated optical element.

Abstract: A system for optically measuring the strength of an AC magnetic field, by an apparatus which includes a sensing head having a magnetooptical element, a polarizer and an analyzer, a light source device for producing a light beam to be transmitted through the sensing head, and a light-sensitive device for converting an optical output of the sensing head into an electric signal. The light beam is modulated by the sensing head to provide the optical output indicative of the strength of the AC magnetic field to which the magnetooptical element is exposed. The magnetooptical element is exposed also to a reference magnetic field different from the AC magnetic field, to thereby bias the light beam while being transmitted through the magnetooptical element. A first and a second component (E.omega.) and (E.sub.2 .omega.) of the electric signal is produced by the light-sensitive device. The first component (E.omega.) has the same angular frequency as that of the AC magnetic field, while the second component (E.sub.2 .

Abstract: A pressure sensor having a ceramic pressure sensing element including a bottom wall serving as a diaphragm, and a tubular wall which extends from a periphery of the bottom wall and cooperates with the bottom wall to define a cavity. The diaphragm has resistors formed thereon. The resistors are electrically connected to an external electric device by electrically conductive members. The sensing element is held in a housing by a retainer member such that one end of the retainer member is aligned with an end face of the tubular wall remote from the bottom wall. A biasing member is provided for biasing the retainer member toward the ceramic pressure sensing element, to exert a retaining force to the sensing element.

Abstract: The invention relates to a pressure sensor including a metallic housing having an open end with an opening, a ceramic diaphragm accommodated within the housing such that the diaphragm is exposed at its one major surface to a pressure of a fluid in an external space through the opening of the housing, and resistors formed integrally on the diaphragm. The electrical resistance of the resistors varies with the pressure acting on the ceramic diaphragm, whereby the pressure is determined by the electrical resistance. An electromagnetic shielding member is disposed within the metallic housing such that the shielding member is positioned between the resistor or resistors and the open end of the metallic housing. The shielding member is adapted to protect the resistors from an electromagnetic wave in the external space.

Abstract: A strain sensor including a ceramic substrate deformable in response to a stress exerted thereon, and an electrically resistive layer formed on the ceramic substrate, so that a strain of the ceramic substrate caused by the stress is detected as a change in a resistance value of the electrically resistive layer. The electrically resistive layer has a composition which includes a dielectric material selected from the group consisting of glasses and ceramics, and at least one principal electrically conductive component in the form of a powder selected from the group consisting of: borides, carbides and nitrides of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W; borides of Y, Sc and lanthanide series; BN; B.sub.4 C; BSi; SiC; and Si.sub.3 N.sub.4.

Abstract: An electrochemical device such as an oxygen sensor comprising a plurality of solid electrolyte bodies, at least one pair of electrodes, each pair being disposed such that the electrodes are held in contact with the solid electrolyte bodies separately, at least one conductor sandwiched by two adjacent ones of the solid electrolyte bodies, and at least one electrical insulation layer. A substantive portion of at least one side of the conductor indirectly contacts with one of the two adjacent solid electrolyte bodies via the electrical insulation layer which is disposed therebetween, whereby the conductor is protected from direct contact with the associated solid electrolyte body. The insulation layer further serves to prevent noises which could otherwise be produced due to leakage current from the conductor. The conductor may be a lead connected to one of the electrodes, or a heater for heating a portion of the solid electrolyte body adjacent to the electrodes.

Abstract: An apparatus for detecting an accident of electric wire lines a single light emitting element, a plurality of optical sensor heads arranged respectively to the lines to be observed, for modulating a light supplied form the light emitting element through a light transmission line in response to electric variations in the line, and a single light receiving element for receiving the synthetic light. Therefore, since the light transmission line is used instead of electric wires, the apparatus has good insulation characteristics and thus the apparatus is not affected by an electromagnetic induction from the electric wire lines. Moreover, since use is made of single light emitting element and single light receiving element, high S/N ratio is realized.

Abstract: A method of manufacturing an electrochemical device having an electrochemical cell including a planar solid electrolyte body and at least two electrodes disposed in contact with the solid electrolyte body. The method comprising: forming a first unfired ceramic layer on one side of an unfired structure of the electrochemical cell, the first unfired ceramic layer being given a porous structure by firing thereof; forming a second unfired ceramic layer on the other side of the unfired structure of the electrochemical cell, the second unfired ceramic layer having substantially the same property of firing shrinkage as the first unfired ceramic layer; and co-firing the unfired structure of the electrochemical cell, the first and second unfired ceramic layers. The two unfired ceramic layers may be formed on opposite sides of an unfired structure of an electrochemical cell assembly which includes plural cells, for example, an oxygen pumping cell and an oxygen sensing cell.

Abstract: An electrochemical element including a planar solid electrolyte body, and at least pair of electrodes including a first electrode and a second electrode which are disposed on the planar solid electrolyte body. The element has a thin flat space which has a predetermined diffusion resistance to a measurement gas and which communicates with an external space in which the measurement gas exists. The first electrode is disposed so that it is substantially exposed to the measurement gas in the thin flat space. The element includes a bridging member which is interposed between two opposed flat surfaces which partially define the thin flat space. The bridging member substantially determines the thickness of the thin flat space. The bridging member is formed by firing a mixture consisting of a filler material which disappears upon firing thereof, and ceramic grains which are fired into the bridging member.

Abstract: An electrochemical device for dealing with a measurement gas in an external measurement-gas space, including an electrochemical sensing element having a pumping cell and a sensing cell. The pumping cell has a first planar solid electrolyte body, and a first and a second electrode disposed on corresponding areas of opposite surfaces of the first solid electrolyte body. The sensing cell has a second planar solid electrolyte body, and a third and a fourth electrode disposed on the second solid electrolyte body. The sensing element has an internal measurement-gas space communicating with the external measurement-gas space, so that the measurement gas is introduced into the internal measurement-gas space with a predetermined diffusion resistance. The first and third electrodes are substantially exposed to the internal measurement-gas space. A reference gas is accommodated in a reference-gas space to which the second and fourth electrodes are substantially exposed to the reference-gas space.

Abstract: An electrochemical device including a sensing element of laminar structure for determining the concentration of a component of a gas, comprising a first electrochemical cell including a first solid electrolyte body, and a first and a second porous electrode disposed on the first solid electrolyte body, a second electrochemical cell including a second solid electrolyte body, and a third and a fourth porous electrode disposed on the second solid electrolyte body, and a ceramic layer having a high electric resistance and sandwiched between the first and second electrochemical cells. In another aspect of the invention, the first solid electrolyte body is porous. In this case, the first and third electrodes are exposed to substantially the same atmosphere. In either case, the first and second, or third and fourth electrodes are disposed in alignment on opposite surfaces of the first or second solid electrolyte body. In the former case, the first and second cells serve as a pumping and sensing cell, respectively.

Abstract: Zirconia powder is formed by dry grinding, and a slurry of the zirconia powder with a nonaqueous solvent is shaped and fired.

Abstract: An electrochemical device of a laminar structure for determining the concentration of a component in a measurement gas, comprising: a pumping cell including a first and a second electrode disposed on a first planar solid electrolyte body; a sensing cell including a third and a fourth electrode disposed on a second planar solid electrolyte body; and a thin flat space to which the first and third electrodes are exposed and which communicates with an external space in which the measurement gas exists. The thin flat space has a diffusion resistance to the component in the measurement gas introduced through an inlet thereof.

Abstract: An electrochemical device comprising at least one electrochemical cell having a planar solid electrolyte body, and a first and a second electrode one of which is disposed on the solid electrolyte body. The device has a measurement-gas space communicating with an outside space for introducing a measurement gas, and a reference-gas space into which a reference gas is introduced. The first and second electrodes are exposed to the measurement-gas and reference-gas spaces, respectively. The measurement gas is introduced into the measurement-gas space with a diffusion resistance to molecules of a selected component of the measurement gas. The measurement-gas and reference-gas spaces are juxtaposed in spaced-apart relation with each other in substantially the same plane parallel to the planar solid electrolyte body.

Abstract: An electrochemical element for detecting a component in a gaseous fluid in an external space, including a planar solid electrolyte body, and a first and a second electrode which are disposed in contact with the planar solid electrolyte body and cooperate with the planar solid electrolyte body to form an electrochemical cell. The electrochemical element has a thin flat space which communicates with the external space and which has a predetermined diffusion resistance to the molecules of the component. A thickness of the thin flat space as measured perpendicularly to a plane of the planar solid electrolyte body is larger at an inlet portion thereof at which the thin flat space communicates with the external space, than at a remote portion thereof remote from the inlet portion. The first electrode is located at the remote portion.

Abstract: A measuring electrode is mounted on one side surface of a solid electrolyte, while a reference electrode is mounted on a separate solid electrolyte and disposed so as to face the opposite side surface of said one solid electrolyte across a gap.

Abstract: An electrochemical device comprising at least one electrochemical cell having a planar solid electrolyte body, and a first and a second electrode one of which is disposed on the solid electrolyte body. The device has a measurement-gas space communicating with an outside space for introducing a measurement gas, and a reference-gas space into which a reference gas is introduced. The first and second electrodes are exposed to the measurement-gas and reference-gas spaces, respectively. The measurement gas is introduced into the measurement-gas space with a diffusion resistance to molecules of a selected component of the measurement gas. The measurement-gas and reference-gas spaces are juxtaposed in spaced-apart relation with each other in substantially the same plane parallel to the planar solid electrolyte body.

Abstract: A process of manufacturing an electrochemical device including a pumping cell having a first and a second electrode, and a sensing cell having a third and fourth electrode such that the electrodes are disposed on at least one solid electrolyte body, and the second and fourth electrodes are exposed to the atmosphere in an internal cavity formed in the device. The process comprises a step of interposing an insert consisting essentially of a sublimable material in the cavity to be formed during superposition of green sheets or layers of the solid electrolyte bodies and electrodes into an unfired laminar structure, such that the insert is disposed opposite to the unfired layers of the second and fourth electrodes, and further comprises a step of co-firing the unfired laminar structure incorporating the insert so as to cause the insert to disappear through sublimation.