Abstract: A pressure sensor has a sensor element portion for detecting pressure, and a pressure conduction portion connectable to a detected member and defining therein a conduction passage for conducting pressure from the detected member to the sensor element portion. A protective cap is detachably attached to the pressure conduction portion to cover a sealed portion where the pressure conduction portion is to be sealed to the detected member until before the pressure sensor is connected to the detected member. The protective cap has an opening portion through which the conduction passage communicates with an outside thereof. Accordingly, pressure characteristics can be checked without detaching the protective cap from the pressure conduction portion.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static electricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A change in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static electricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A change in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static electricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A change in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A semiconductor sensor chip mounted on a thin diaphragm of a cylindrical metallic stem via an insulation layer is hermetically contained in a housing of a pressure sensor. The sensor chip includes a strain gage for outputting an electrical signal according to distortion of the diaphragm caused by pressure to be measured. A shield layer is interposed between the insulation layer and the sensor chip, and the shield layer is grounded. Influence of outside noises on the sensor outputs is eliminated or suppressed by the grounded shield layer even if the outside noises are in a high frequency region.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static electricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A change in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A case of a pressure sensor has an atmospheric pressure introduction port for introducing atmospheric pressure into the case, and a water repellent filter that is attached to the atmospheric pressure introduction port to prevent passage of moisture, dust and the like while allowing flow of air. The filter is disposed to have a filter surface extending along a gravitational direction when the pressure sensor is used.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static electricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A change in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static electricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A change in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A pressure sensor portion having a pressure-responsive element for detecting gas pressure in reference to the atmospheric pressure is connected to a mounting body such as a canister mounted on a vehicle by means of a fragile connecting member. The connecting member breaks off to dismount the sensor device from the mounting body when a high impact due to an accidental collision or crash is imposed on the sensor device, and thereby an inlet port connected to the sensor portion for introducing gas pressure thereinto is prevented from being broken or damaged by such a collision impact. The fragile connecting member may include a tubular pipe formed integrally with a cover that hermetically closes an inner cavity of the sensor portion. A mounting bracket connected to the sensor portion via the fragile connecting member may be used to mount the sensor device on the mounting body.

Abstract: When a compressed air is led into a reference pressure chamber along with a boundary between a resin housing and a terminal, such compressed air may cause a wire breaking. A barrier wall for blocking the compressed air from penetrating toward the wire is disposed. The reference pressure chamber is divided into a main chamber and a subchamber by the barrier wall. Since the barrier wall blocks the compressed air, the compressed air can not reach a silicon gel in the main chamber. Therefore, the wire breaking caused by the compressed air when connecting a connector therewith can be precluded.

Abstract: A pressure detecting apparatus includes a sensing body with a diaphragm to which pressure is applied and a strain gauge plate having a {100} silicon substrate and a glass base, which is bonded on the sensing body. A thin portion and through holes are formed in the silicon substrate so that the thin portion has a beam structure on which strain gauges are formed. When the pressure is applied, the resistances of the strain gauges change in a positive direction, while the resistances of the strain gauges change in a negative direction. Accordingly, the linearity of the output from the pressure detecting apparatus can be improved.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static electricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A charge in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A pressure sensor has a resin housing containing a pressure sensor positioned between a reference pressure chamber and a pressure to be measured. A terminal extends through the housing toward the sensor. A wire connects the terminal to the sensor. When a connector is connected to the terminal, it may compress air around the terminal. The compressed air may travel along the terminal and break the wire connected to the sensor. To prevent such breakage, a barrier wall is provided to block the compressed air from penetrating toward the wire. The reference pressure chamber is divided into a main chamber and a subchamber by the barrier wall. Since the barrier wall blocks the compressed air, the compressed air can not reach a silicon gel on the sensor and the wire in the main chamber. Therefore, the wire is protected.

Abstract: A knock sensor for which a fabrication process is simple and moreover which can detect up to a high-frequency region is provided. A sensing element 11 composed of a semiconductor the weight (mass) thereof being 1 g or less and a signal processing circuit 11 are mounted on a fixing pedestal 9. The fixing pedestal 9 is fixed to a connector 2 side by means of adhesive or the like. Additionally, the connector 2 is fixed by means of caulking 16 of a housing 1. As a result thereof, the sensing element 11 is disposed within a space formed by the fixing pedestal 9 and the housing 1.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static electricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A change in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A semiconductor accelerometer which can satisfy the requirements of both the sensitivity and the fracture strength without any contrivance for providing viscous liquid and beam stopper material is provided. A casing comprises a stem and a shell. The casing houses an accelerometer chip. The silicon accelerometer chip is of double cantilever beam structure. Each beam is provided with piezo resistance layers. The motion of the beams due to the action of acceleration is converted into electrical signals. The resonant frequency of the beams of the accelerometer chip is above the resonant frequency of the casing itself, so that the acceleration components above this resonant frequency are damped by the casing and therefore most acceleration components in the resonant frequency of the beam are damped. As a result, the beams of the accelerometer chip can be protected from the impacts due to the dropping of the accelerometer, or the like.

Abstract: A semiconductor mechanical sensor having a new structure in which a S/N ratio is improved. In the central portion of a silicon substrate 1, a recess portion 2 is formed which includes a beam structure. A weight is formed at the tip of the beam, and in the bottom surface of the weight in the bottom surface of the recess portion 2 facing the same, an electrode 5 is formed. An alternating current electric power is applied between the weight portion 4 and the electrode 5 so that static electricity is created and the weight is excited by the static eletricity. In an axial direction which is perpendicular to the direction of the excitation of the weight, an electrode 6 is disposed to face one surface of the weight and a wall surface of the substrate which faces the same. A change in a capacitance between the facing electrodes is electrically detected, and therefore, a change in a physical force acting in the same direction is detected.

Abstract: A semiconductor strain sensor having a stem with a lead hole in which a lead terminal is installed and electrically coupled to an external circuit. A sensor chip having piezo-resistors to a bride circuit is joined with a front surface of the stem. A shell is joined with the front surface of the stem by projection welding after the back surface of the stem is flattened to within a predetermined limit. A space formed by the shell and stem is filled with a damping liquid. The stem is integrally coupled to the sensor chip through an adhesive, and spacers are added to the adhesive to keep the thickness of the adhesive to a predetermined value. This arrangement can effectively prevent propagation of the welding strain of the stem from adversely affecting the sensor chip.

Abstract: When an acceleration sensor is used, it is attached to a measured object to detect an acceleration applied to the object. The acceleration sensor includes a package having at least one chamber. A sensor element is disposed in the chamber and has a portion which vibrates in response to the acceleration. Damping liquid is sealed within the package and has a quantity which allows the sensor element to be submerged in the damping liquid and which allows a predetermined quantity of gas to remain in the package. The gas absorbs a thermally-induced volume change of the damping liquid. In the absence of the acceleration, a gas bubble is prevented from separating from the gas. In addition, the gas bubble is prevented from staying in the chamber.