Abstract: The present invention is for enlarging a freedom of layout including an air bridge pattern and enhancing the availability for various purposes. A mask layer including an air bridge pattern is formed on a (100) plane of a silicon substrate, isotropic etching is carried out until a point of intersection between tangents of a peripheral curved plane comes to under the air bridge pattern plane, and then an air bridge is formed by means of anisotropic etching.

Abstract: A flow sensor includes a first heating portion, provided at a first position in a flow of a fluid, which heats the fluid and outputs a voltage in response to a temperature of the first position. A second heating portion, provided at a second, downstream position in the flow of the fluid, heats the fluid and outputs a voltage in response to a temperature of the second position, the first position and the second position being spaced from each other in a direction parallel to the flow of the fluid. An intermediate heater, provided between the first heating portion and the second heating portion, heats the fluid at an intermediate position between the first position and the second position.

Abstract: A piezo-electricity generation device without an external power supply unit includes a rectifying means which rectifies an AC voltage generated by the vibration of at least one piezo-electric plate. An accumulating means accumulates an electric charge outputted through the rectifying means. A voltage setting means provides a prespecified voltage. A transmission means transmits substantially all of the electric charge accumulated in the accumulating means to a signal output means when the output voltage of the accumulating means exceeds the prespecified voltage set by the voltage setting means. A timing setting means may also or alternatively be provided for setting a prespecified timing such that the transmission means transmits substantially all of the electric charge stored in the accumulating means at the prespecified timing set by said timing setting means.

Abstract: A flow sensor eliminates turbulence of fluid flow due to a structure of the temperature detecting portion so that a temperature of the temperature detecting portions does not fluctuate due to the turbulence of the fluid. The flow sensor is formed on a substrate. Each of a first temperature detecting portion and a second temperature detecting portion has a heating function and a temperature detecting function, and are arranged along a direction of flow of the fluid. A supporting portion is formed on the substrate for supporting the first and second temperature detecting portions thereon. The supporting portion does not have a side surface facing substantially in the direction of flow of the fluid. A side surface of the supporting portion is protected by a guard portion formed along the side surface.

Abstract: A thermo-sensitive flow sensor includes a bridge circuit, an amplifying circuit and a sensor drive circuit. A bridge circuit adjusting amplifier is further provided and is connected to an output side of the sensor drive circuit for receiving an output therefrom. The output of the sensor drive circuit is adjusted via the bridge circuit adjusting amplifier and is fed back to the bridge circuit so that the balance adjustment of the bridge circuit is automatically performed based on the value fed back to the bridge circuit. An offset voltage adjusting amplifier may be provided instead of, or in addition to, the bridge circuit adjusting amplifier and is connected to the output side of the sensor drive circuit for receiving the output therefrom.

Abstract: Disclosed is a flow sensor for sensing heat transfer with a high-speed response, which is manufactured by applying IC micro-machining technology, and which attains an improved heat transfer efficiency by controlling the flow's direction between a heating portion and a sensing portion or by utilizing the intrinsic characteristics of the gas flow.A flow sensor having a substrate whereon a heating portion and a sensing portion are formed each in the form of a bridge supported at both ends or at one end in said order in the direction of the flowing gas to be measured, and which is placed, its surface with the elements down, at the upper inside wall of a pipe for gas to be measured. Its output signal is taken out through lead wires.

Abstract: Disclosed is a flow sensor for sensing heat transfer with a high-speed response, which is manufactured by applying IC micro-machining technology, and which attains an improved heat transfer efficiency by controlling the flow's direction between a heating portion and a sensing portion or by utilizing the intrinsic characteristics of the gas flow.A flow sensor having a substrate whereon a heating portion and a sensing portion are formed each in the form of a bridge supported at both ends or at one end in said order in the direction of the flowing gas to be measured, and which is placed, its surface with the elements down, at the upper inside wall of a pipe for gas to be measured. Its output signal is taken out through lead wires.

Abstract: A thermally-sensitive type flow meter measures a flow rate with a high accuracy by eliminating a noise generated in a source voltage. The flow meter includes a sensor chip comprising a substrate carrying sensing elements. First and second resistors are provided on first and second bridges formed over a depression formed on the substrate. The first bridge is positioned on an upstream side and the second bridge is positioned on a downstream side. The first and second resistors generate a heat by the same voltage source. First and second temperature measuring resistors are provided adjacent to the first and second resistors, respectively, to measure a temperature of the first and second resistors. Third and fourth temperature measuring resistors are provided for measuring the temperature of the fluid. A temperature control unit, including the first, second, third and fourth temperature measuring resistors, controls a temperature of each of the first and second resistors to be constant.

Abstract: The present invention is for enlarging a freedom of layout including an air bridge pattern and enhancing the availability for various purposes. A mask layer including an air bridge pattern is formed on a (100) plane of a silicon substrate, isotropic etching is carried out until a point of intersection between tangents of a peripheral curved plane comes to under the air bridge pattern plane, and then an air bridge is formed by means of anisotropic etching.

Abstract: A low-cost and quick-response type gas-density sensing element is free from positioning error of sensing ambient temperature and gas density and can accurately sense the gas flow even if the environmental conditions sharply change. An output voltage V.sub.1 proportional to an ambient temperature is obtained by heating a sensing element at low temperature and an output voltage V.sub.2 proportional to the ambient temperature and humidity is obtained by heating the sensing element at a high temperature. An output voltage which is proportional to the humidity is obtained by subtracting the voltage value V.sub.1 from the voltage value V.sub.2.

Abstract: The present invention is to provide a compact and high speed tunnel transistor having a high input impedance, yet consuming only a small quantity of power. In a tunnel transistor according to the present invention, a gate electrode is provided via an insulating thin film on a Schottky junction which is a junction between a semiconductor and a metallic layer, a p-n.sup.+ junction between semiconductors, or an n-p.sup.+ junction between semiconductors so that an accumulation layer having a high carrier density is formed bear the surface of a semiconductor by adjusting a gate voltage Vg and thus a tunnel junction is formed between this accumulation layer and a metallic layer or a semiconductor having a high carrier density (n.sup.+ or p.sup.+) by adjusting the gate voltage Vg.

Abstract: In the drive control apparatus for microsensor according to the present invention, power is constantly supplied to the microsensor. Also the peripheral humidity is detected, and control is switched between pulse drive control and constantly energized drive control according to the detected value. Also the pulse drive voltage is always supplied in an energized state.

Abstract: A flow sensor for sensing heat conduction with a high-speed response, and manufactured by applying IC micro-machining technology to have a reduced clearance between the heating portion and the sensing portion. The flow sensor has a substrate having a through hole or a cavity formed therein, whereon a heating portion and a sensing portion are formed each in the form of a layer bridged over the through hole or the cavity and supported at both ends or at one end. The heating portion and the sensing portion are laminated in two or three or more layers spaced from each other and arranged along the flow of gas to be measured. Each inner layer space is fine and accurate by precisely forming a very thin film that is removable.

Abstract: A flow sensor is disclosed, which has a thin film heater which is formed atop a cavity formed in the substrate, and the thin film heater is formed on its upstream and downstream sides with slits for separating it and temperature sensors from the substrate. The slits have such a small width that a laminar flow of gas can be maintained. In the case where the film heater has a positive resistance temperature coefficient, the thin film heater is disposed such that current flows in a direction of the gas stream, in case when the film heater has a negative temperature coefficient, the thin film heater is disposed such that current flows in a direction perpendicular to the gas stream.

Abstract: A flow sensor for sensing heat transfer with a high-speed response, which is manufactured by applying IC micro-machining technology, and which attains an improved heat transfer efficiency by controlling the flow's direction between a heating portion and a sensing portion or by utilizing the intrinsic characteristics of the gas flow. The flow sensor has a substrate whereon a heating portion and a sensing portion are formed each in the form of a bridge supported at both ends or at one end in the direction of the flowing gas to be measured, and which is placed, its surface with the elements down, at the upper inside wall of a pipe for gas to be measured. Its output signal is taken out through lead wires.

Abstract: The present invention comprises a first process to enclose a floating single crystal thin film with a enclosure material which is hardly affected by an isotropic etchant using a face with the lowest etch rate against an anisotropic etchant as a front surface of a single crystal substrate, a second process to cover a portion of or the entire surface of the single crystal substrate with a cover material which is hardly etched by the anisotropic etchant nor by the isotropic etchant, a third process to form an etched groove by etching and removing a portion of the single crystal substrate in the outer side or under a region enclosed by the enclosure material using the isotropic etchant, and a fourth process to deposit a floating single crystal thin film by etching and removing a portion of the single crystal thin film using the anisotropic etchant and making use of the etched groove.

Abstract: A gas detecting device includes a substrate, an insulating layer supported by the substrate, first and second pairs of detection leads formed on the insulating layer, a heater lead formed on the insulating layer, the first and second pairs of detection leads being heated by passing a heater driving current through the heater lead, a gas sensitive layer formed of a gas sensitive material and provided so as to partially make contact with the first and second pairs of detection leads, and a passivation layer formed so as to cover the first and second pairs of detection leads and the heater lead. A gas detection signal is output from the gas sensitive layer through one of the first and second pairs of detection leads. A gas detecting system including the above gas detecting device is also provided.

Abstract: A gas detecting device includes a substrate, an insulator layer formed on the substrate, a gas sensitive layer formed the insulator layer, a pair of detection leads formed on the insulator layer, the gas sensitive layer partially overlying the pair of detection leads, a signal derived from the gas sensitive layer being sent to an external circuit through the pair of detection leads, a heater member arranged on the insulator layer in the vicinity of the gas sensitive layer, and an insulation coating layer formed on the pair of detection leads and the heater member, and partially overlying the gas sensitive layer so that the gas sensitive layer is put between the insulator layer and the insulation coating layer, and a portion of an upper surface of the gas sensitive layer is exposed to gas.