A compact microelectronic gas sensor module includes electrical contacts formed in such a way that they do not consume real estate on an integrated circuit chip. Using such a design, the package can be miniaturized further. The gas sensor is packaged together with a custom-designed Application Specific Integrated Circuit (ASIC) that provides circuitry for processing sensor signals to identify gas species within a sample under test. In one example, the output signal strength of the sensor is enhanced by providing an additional metal surface area in the form of pillars exposed to an electrolytic gas sensing compound, while reducing the overall package size. In some examples, bottom side contacts are formed on the underside of the substrate on which the gas sensor is formed. Sensor electrodes may be electrically coupled to the ASIC directly, or indirectly by vias.

A gas sensor includes a sensor element including an element body, a first electrode, a second electrode, and a heater; a voltage acquisition section that acquires a voltage between the first electrode and the second electrode; a heater power supply; an external common lead that serves as both at least part of an electric circuit used to acquire the voltage by providing electrical continuity between the first electrode and the voltage acquisition section and at least part of an electric circuit used to supply an electric power from the heater power supply to the heater and that is disposed outside the sensor element; and a correction section that derives a value of a voltage drop in the external common lead in accordance with a heater current and that corrects the voltage acquired by the voltage acquisition section in accordance with the derived value of the voltage drop.

A sensor includes a sensing element, a first pair of lead wires, a second pair of lead wires, a grommet, and a shell. The first pair of lead wires is fixed to the sensing element and configured to receive signals from the sensing element. The second pair of lead wires is electrically connected to the first pair of lead wires at a joint. The second pair of lead wires is configured to receive signals from the first pair of lead wires. The grommet houses the joint, a portion of the first pair of lead wires, and a portion of the second pair of lead wires. The shell houses the sensing element, the first pair of lead wires, and the grommet. The shell engages and deforms the grommet to seal an interior space defined by the shell.

A gas sensor includes a sensor element and a contact metal fitting. The sensor element has an element body having an oxygen-ion-conductive solid electrolyte layer; an upper connector electrode disposed outside the element body; a lead disposed outside the element body and electrically conductive to the upper connector electrode; and a first protection layer that covers the lead, where a thickness T1 of a portion covering the lead is 2 .Math.m or more, a porosity P1 is 20% or less, and a height difference D1 relative to the upper connector electrode is 22 .Math.m or less. The contact metal fitting has: a conduction member that projects to the upper connector electrode and is in contact with and electrically conducted to the upper connector electrode; and a support member that projects toward the lead and is in contact with the first protection layer.

An insulating separator of a gas sensor is formed to be dividable into a forward separator having a terminal disposition hole, and a rear separator having four terminal disposition holes. The insulating separator has a ventilation path formed between the forward separator and the rear separator. As a result, moisture and the like which enter the insulating separator from a forward side of the forward separator through the terminal disposition hole can be discharged outward of the insulating separator through the ventilation path. As a result, corrosion of metal terminals caused by entry of moisture can be reduced, whereby transmission of a sensor signal and application of current or voltage through the metal terminals can be appropriately implemented.

A metal terminal of a gas sensor includes a forward terminal member and a rear terminal member. The forward terminal member is made of a material superior in heat resistance to and greater in “0.2% yield strength” than a material of the rear terminal member. The forward terminal member has heat resistance suitable for a portion which comes into contact with a high-temperature detection element and is larger in an elastic deformation region than the rear terminal member, thereby providing good contact with the detection element and thus facilitating maintenance of electrical contact with the detection element. The rear terminal member is unlikely to have springback at a signal-wire connection portion to be connected to a lead wire, thereby facilitating maintenance of electrical connection with the lead wire.

Disclosed is a gas sensor element having an electrode containing a first metal as a predominant component and a lead containing a second metal as a predominant component. The electrode and the lead are connected directly at a connection boundary thereof, or connected indirectly via a connection joint. The connection boundary or joint includes a component region where either one of the first and second metals lower in specific gravity than the other of the first and second metals is contained in an amount ranging between those in the electrode and the lead.

A sensor including a sensor element, a metallic shell, a terminal fitting, a cylindrical case, lead wires, a connector portion, and a cylindrical heat shield tube. The heat shield tube includes a first tube and a second tube. The second tube is disposed on a distal end side of the first tube and covers an outer surface of the rear end side of the case, while providing an overlapping portion that overlaps the first tube. A rear end side of the first tube is adjacent to the connector portion. A total length T of the heat shield tube and a length S of the overlapping portion satisfy T/10≤S≤T/5. Further, a length L1 of the first tube and a length L2 of the second tube satisfy T/2≤L2<L1.

The gas sensor is equipped with a sensor device, a plurality of electrode springs contacting with electrodes and of the sensor device, an insulator retaining the electrode springs, and a plurality of leads connected to the respective electrode springs. Each of the electrode springs includes a retained portion retained by the insulator and a contact portion which is bent and inclined from the retained portion toward a front end side of the sensor device in the lengthwise direction. The contact portion is elastically deformed in contact with the electrode. Each of the electrode springs also includes a bent portion between the contact portion and the retained portion. The bent portion constitutes a base end of the contact portion and is oriented toward the base end side of the gas sensor in the lengthwise direction, thereby enabling the length of the sensor device to be decreased and improving the heat resistance of the electrode springs.

The gas sensor includes a sensor element, a first insulator inside which the sensor element is inserted, a second insulator disposed on a proximal side of the first insulator so as to cover a proximal side of the sensor element, and a contact member held by the second insulator and sandwiching the sensor element. A proximal end portion of the first insulator and a distal end portion of the second insulator abut on each other in an axial direction. Each the proximal end portion and the distal end portion is provided with a positioning structure. The positioning structure is configured to restrict a relative movement between the first and second insulators in a sandwiching direction in which the sensor element is sandwiched by the contact member and in an orthogonal direction perpendicular to the sandwiching direction and in the axial direction.