Hitachi, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Hitachi Car Engineering Co., Ltd.

Other

Hitachi, Ltd. and Hitachi Car Engineering Co., Ltd.

Norio Ichikawa

Sadayasu Ueno

Junichi Horie

Masahiro Matsumoto

Satoshi Shimada

Keiji Hanzawa

Akihiko Saito

Atsushi Miyazaki

Yasuo Onose

Kanemasa Sato

Seiji Kuryu

Masayuki Miki

Seiko Suzuki

Masayoshi Suzuki

Yukiko Sugisawa

Kazuo Sato

Takao Sasayama

Takeshi Harada

Masatoshi Kanamaru

Akira Koide

Seikou Suzuki

Akio Yasukawa

Shigeki Tsuchitani

Takayuki Itsuji

Yoshiro Ibaraki

Hiromichi Ebine

Kazuhiro Tsuruoka

Keizi Hanzawa

Yuuji Ogasawara

Seijiro Takeda

Atsuo Watanabe

Masahide Hayashi

Hiroshi Moriya

Hidehito Obayashi

Tomoyuki Tanaka

Terumi Nakazawa

Katsuyoshi Terakado

Masanori Kubota

Yasuhiro Asano

Benjamin Kloeck

Yukiko Kawai

Akihiko Saitou

Takauki Ituzi

A sensor with built-in circuits can be improved in the stability of the operation or characteristics. A circuit region and a sensor region are covered by a passivation film. The sensor region is partially covered by the passivation film. The sensor region and circuit region are protected by the passivation film, and an effect of the passivation film on the mechanical displacement of a diaphragm portion can be alleviated so that the sensor with built-in circuits may be improved in the stability of the operation or characteristics.

Sensor with built-in circuits and pressure detector using the same

By sealing a diaphragm with less processes and lower cost and reducing deformation due to remaining stress, a stable and highly reliable pressure sensor construction is proposed. The pressure sensor is low in measurement error and small in floating capacitance and leakage current and good in characteristic. As a means to attain the above object, a polycrystalline silicon diaphragm is sealed with a silicon oxide film deposited through a LPCVD method and then completely covered. The diaphragm is placed on a surface of a semiconductor substrate with a nearly constant gap of 0.15 to 1.3 &#x3bc;m, and has difference-in-grade constructions of a deformation reducing means due to remaining stress.

Capacitive type pressure sensor

A high-accuracy high-stability capacitor type pressure sensor which eliminates a parasitic capacitance between a reference capacitor and a semiconductor substrate. A capacitor type pressure sensor comprising, on a semiconductor substrate , an active capacitor whose capacitance varies as the surrounding pressure varies, a reference capacitor whose capacitance will not vary substantially as the surrounding pressure varies, and a circuit which is electrically connected to both said active and reference capacitors and detects the difference or ratio thereof, and uses the potential of a semiconductor substrate, wherein an electrode of said reference capacitor is formed on the semiconductor substrate with a dielectric therebetween.

Capacitive pressure sensor

Dynamic quantitative displacement is converted stably and straight into voltage (D.C. output) by using a high speed detection driving frequency without restricting a response of an operational amplifier. When a dynamic quantity detection electrostatic capacitance changes according to a dynamic quantity, electric charges stored in this element and in a reference electrostatic capacitance become unbalanced to produce a difference value, and an output of an operational amplifier changes according to the difference in electric charge quantity. However, the output becomes finally stable when the electric charges in the dynamic quantity detection electrostatic capacitance and in the reference electrostatic capacitance become equal. The output is proportional to a reciprocal of the dynamic quantity detection electrostatic capacitance and it is a D.C. voltage. Further, output without depending on integration feedback capacitance (feedback condenser) CF can be obtained.

Electrostatic capacitance type dynamical quantity sensor

In a capacitance type pressure sensor, a diaphragm is formed of a fragile material using an impurity-diffused monocrystal silicon and constitutes a stable pressure-responsive structure which does not undergo a plastic deformation. Between the diaphragm and a movable electrode is formed an oxide film to diminish stray capacitance between the movable electrode and a substrate and also between the movable electrode and a impurity-diffused layer. The oxide film and the movable electrode are each divided into plural regions so that the divided regions of the movable electrode are formed on the divided regions of the oxide film, thereby diminishing stress strain induced by a difference in therm expansion coefficient among the diaphragm, oxide film and movable electrode. The upper surface of a fixed electrode is covered with a structure for the fixed electrode which structure is formed by an insulating polycrystal silicon film not doped with impurity whereby the rigidity of the electrode is enhanced and it is possible to diminish a leak current.

Capacitance type pressure sensor with capacitive elements actuated by a diaphragm

A semiconductor pressure sensor utilizing electrostatic capacitance has a plurality of pressure sensing electrostatic capacitances and a reference electrostatic capacitance formed on one side of a silicon chip. As a movable electrode, the pressure sensing electrostatic capacitances each have a diaphragm, which may have a displacement portion composed of a central area thereof, and a peripheral portion which is more deformable than the central portion.

Semiconductor pressure sensor including reference capacitor on the same

A capacitance acceleration sensor and method of making same are disclosed. A capacitance acceleration sensor includes a movable electrode etched from a silicon plate which is clamped between two solid dielectric plate members of glass, silicon oxides, or oxygen oxides. Static electrodes are secured to surfaces of the dielectric members facing opposite the movable electrode, thereby providing easy manufacturing assessibility for leadout wires from these electrodes. In certain embodiments, the movable electrode is formed integrally with a monocrystalline silicon plate member which also contains an integrated circuit for generating an output acceleration signal in response to movement of the movable electrode when the assembly experiences acceleration forces.

Method of making a capacitance type acceleration sensor

A capacitance acceleration sensor includes a movable electrode etched from a silicon plate which is clamped between two solid dielectric plate members of glass, silicon oxides, or oxygen oxides. Static electrodes are secured to surfaces of the dielectric members facing opposite the movable electrode, thereby providing easy manufacturing assessibility for leadout wires from these electrodes. In certain embodiments, the movable electrode is formed integrally with a monocrystalline silicon plate member which also contains an integrated circuit for generating an output acceleration signal in response to movement of the movable electrode when the assembly experiences acceleration forces.

Capacitance type acceleration sensor

A semiconductor acceleration sensor is formed by a cantilever having a conductive movable electrode of predetermined mass at one end, at least one pair of fixed conductive electrodes which are stationary with respect to the movable electrode located on opposing sides of the movable electrode, and gaps provided between the movable electrode and the fixed electrodes. To prevent the movable electrode becoming fused to the contacted fixed electrode, in a first aspect of this invention, an insulating layer is provided between the movable electrode and fixed electrodes, the layer being either on the movable electrode or on the fixed electrodes and in a second aspect the movable electrode or, preferably, the fixed electrodes, are formed of a high melting point material. In such a second aspect, to improve adhesion between the high melting point material and a substrate to which the fixed electrodes are mounted, a lower melting point material is firstly coated on the substrates. A sensor detector unit processing circuit has the output characteristic of the circuit digitally adjusted by suitable switching of a plurality of resistors, and the sensor chip and the detector unit integrated circuit may be located on a common base and mounted in a hermetically sealed chamber to prevent adverse environmental effects affecting operation of the sensor and detector unit assembly. A gas having a dew point of -40.degree. C. or lower is, advantageously, charged into the hermetically sealed chamber.

Semiconductor acceleration sensor and vehicle control system using the

A method of manufacturing structures such as a pressure gauge, an accelerometer and the like with a single crystal material such as silicon uses etching techniques where the shape of a part subjected to stress concentration has a curvature, another part is formed in a plane body and a polyhedron is constituted by combining both. To attain the above constitution, a wafer of single crystal material is formed with a stepped surface having a value corresponding to at least the depth of the curvature in a first anisotropic etching process using a prescribed etching mask, and in a second anisotropic etching process, an etching mask is used by removing at least a part of the etching mask used in the first anisotropic etching process.

Structure and method of manufacturing the same

A capacitive type semiconductor accelerometer has an intermediate silicon plate of n type conductivity including a movable electrode constituting a pendulum mass formed within the intermediate silicon plate and supported thereby via a beam so as to permit movement in a direction perpendicular to its plane. A first conductive island is formed within the intermediate plate and is immovably supported thereby via a first insulating leg so as to be isolated therefrom, and an upper glass plate is anodic bonded to the intermediate silicon plate. A first stationary electrode is formed on the upper glass plate at the position facing one face of the movable electrode with a predetermined gap. A lower glass plate is anodic bonded to the intermediate silicon plate and a second stationary electrode is formed on the lower glass plate at the position facing the other face of the movable electrode with a predetermined gap. First, second and third pads are disposed in common on the lower glass plate at the outside of the intermediate silicon plate, the first pad being electrically connected to the first stationary electrode via a first thin film lead formed on the lower glass plate and the first conductive island, the second pad being electrically connected to the movable electrode via a second thin film lead formed on the lower glass plate and the intermediate silicon plate and the third pad being electrically connected to the second stationary electrode via a third thin film lead formed on the lower glass plate.

Capacitive type semiconductor accelerometer

The invention relates to a gas sensor for measuring an air-fuel ratio of an air-fuel mixture of an internal combustion engine and to a method of manufacturing the gas sensor. The sensor of the invention comprises: a solid state electrolyte layer made of an oxygen ion conductive metal oxide; a first electrode of a porous thin film having the catalyst function which was coated on one surface of the solid state electrolyte layer; a second electrode of a porous thin film having the catalyst function which was coated on the other surface of the solid state electrolyte layer; an electrode shielding layer made of a sintered material of ultra fine particulates whose average grain diameter is 1 .mu.m or less which covers the surface other than the region of a predetermined area of the second electrode; and a gas diffusion layer made of a porous electric insulative metal oxide which covers the region of the predetermined area of at least the second electrode.

Gas sensor for measuring air-fuel ratio and method of manufacturing the

An air-fuel ratio control apparatus for an internal combustion engine includes a solid electrolyte having a first electrode disposed on one surface thereof to contact with the atmosphere and a second electrode disposed on the other surface thereof to contact with the exhaust gas from the engine through a diffusing resistor, and means for applying a voltage across the first and second electrodes to detect an oxygen pump current flowing in the solid electrolyte whereby a correction factor relating to a change in the diffusion coefficient of the diffusing resistor is computed so that the oxygen pump current detected by the detecting means is corrected in accordance with the correction factor and the air-fuel ratio of the exhaust gas is determined in accordance with the corrected oxygen pump current, thereby controlling the quantity of fuel supplied to the engine in accordance with the determined air-fuel ratio.

Air-fuel ratio control apparatus for internal combustion engines

An air/fuel ratio (A/F) sensor for detecting the A/F over a wide range covering a lean region and a rich region which are partitioned by the stoichiometric A/F comprises a solid electrolyte made of an oxygen ion conductive metal oxide, first and second electrodes sandwiching the solid electrolyte and being operable by a predetermined voltage applied thereacross to ionize oxygen near the solid electrolyte and diffuse oxygen ions into the solid electrolyte, and a gas diffusion layer in the form of a porous sintered layer covering the second electrode and made of electrically insulative metal oxide fine particles having a mean particulate size of 1 .mu.m or less so that oxygen or molecules of other gas components in the exhaust gas can move through pores of the gas diffusion layer.

Sensor for measurement of air/fuel ratio and method of manufacturing

In an apparatus of the type in which the air-fuel ratio of an engine is detected by an air-fuel ratio sensor and the air-fuel ratio is feedback-controlled in accordance with the detection result to operate the engine at a desired air-fuel ratio, a change of the output characteristic of the air-fuel ratio sensor is always corrected for. The apparatus includes means for detecting the air-fuel ratio of the engine from its exhaust gas composition, means for determining whether the engine is in a given constant operating condition, means for determining a desired air-fuel ratio for the constant operating condition, means for supplying the quantity of fuel corresponding to the desired air-fuel ratio to each cylinder of the engine, means for causing some of all the cylinders of the engine not greater in number than N-1 (N represents the total number of cylinders) to misfire when the engine comes into the constant operating condition, and means for correcting the output characteristic of the air-fuel ratio detecting means in accordance with the amount of change of the output of the air-fuel ratio detecting means before and after the misfiring.

Air-fuel ratio control apparatus for multicylinder engine

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Mito, Japan

Norio Ichikawa