Abstract: Technique of suppressing performance variations for each flow sensor is provided. In a flow sensor FS1 of the present invention, a part of a semiconductor chip CHP1 is configured to be covered with resin (MR) in a state in which a flow sensing unit (FDU) formed on a semiconductor chip CHP1 is exposed. Since an upper surface SUR(MR) of the resin (MR) is higher than an upper surface SUR(CHP) of the semiconductor chip (CHP1) by sealing the resin (MR) on a part of the upper surface SUR(CHP) of the semiconductor chip CHP1 in a direction parallel to an air flow direction, the air flow around the flow sensing unit (FDU) can be stabilized. Further, interface peeling between the semiconductor chip (CHP1) and the resin (MR) can be prevented by an increase of contact area between the semiconductor chip (CHP1) and the resin (MR).

Abstract: It is an object of the present invention to improve a measurement accuracy of a thermal flow meter. A circuit package 401 is such that a measurement surface 430 and a backside of measurement surface 431 of a rear surface thereof are located in a bypass passage, and the bypass passage is configured to allow a measurement target gas 30 to flow upon dividing the measurement target gas 30 into a flow path 386 at a side of the measurement surface 430 of the circuit package and a flow path 387 at a side of the backside of measurement surface 431 of a rear surface of the measurement surface 430, and an inflow-side end surface of the circuit package for dividing the measurement target gas 30 has different shapes at the side of the measurement surface and at the side of the backside of measurement surface.

Abstract: When an exposed part of a semiconductor chip is reduced in size, a tendency of development of a crack on the semiconductor chip is suppressed. A pressure of injection of a resin MR into a second space creates a gap on a contact part SEL where an elastic film LAF and a semiconductor chip CHP1 are in contact, and a resin MR2 different in constituent from the resin MR infiltrates into the gap. As a result, in an area of semiconductor chip CHP1 that is exposed from the resin MR, the resin MR2 is formed in an area other than a flow detecting unit FDU and an area around it. Hence, an area of semiconductor chip CHP1 that is exposed from the resins MR and MR2 can be reduced in size.

Abstract: In order to provide a thermal flow meter (300) for improving workability of a flow rate measurement device having a temperature measurement function for the measurement target gas (30) and measurement accuracy for measuring a temperature, the thermal flow meter is structured such that a flow rate measurement circuit package (400) having a protrusion (424) for measuring a gas temperature is formed through resin molding, an inlet port (343) opened to the upstream side of the measurement target gas (30) is formed, a protrusion (424) is arranged inside the inlet port, an inlet port (344) and an outlet port (345) are formed in the front and rear covers (303 and 304) along the protrusion (424), and the measurement target gas (30) received from the inlet port (343) flows along the protrusion (424). Since the measurement target gas (30) subjected to the measurement flows along the protrusion (424), it is possible to reduce influence of the heat from other heat resources and improve measurement accuracy.

Abstract: The present invention is to improve measurement accuracy of a thermal flow meter. In a thermal flow meter of the invention, a circuit package 400 includes a processing unit 604 in which a passage 605 and a circuit are disposed. An air flow sensing portion 602 is disposed in the passage 605. A fixing portion 372 is integrally formed with and fixed to the circuit package 400 and forms a bypass passage. The passage 605 of the circuit package 400 is arranged inside the bypass passage. In the bypass passage, a storage portion 384 having a concave portion 383 is formed to face the fixing portion 372. At least a part of the leading end 401 of the circuit package 400 is contained in the concave portion 383 of the storage portion 384.

Abstract: The present invention provides a thermal flow meter which can suppress a degradation of measurement accuracy caused by deformation of a diaphragm and a stained rear surface thereof even in a case where a gap is provided in order to form the diaphragm in an air flow sensing element. The present invention relates to a thermal flow meter 300 which includes a bypass passage through which a measurement target gas 30 received from a main passage 124 flows, and an air flow sensing element which measures a flow rate of the measurement target gas 30 by performing heat transfer with the measurement target gas 30 flowing through the bypass passage. The thermal flow meter 300 includes at least a circuit package 400 which contains the air flow sensing element 602. A gap 674 is formed in a rear surface of the air flow sensing element 602 to form a diaphragm 672 in an air flow sensing area 437 of the air flow sensing element 602, and the gap 674 becomes a sealed space reduced in pressure compared to an atmospheric pressure.

Abstract: Provided is a thermal flow meter that can be prevented from being eroded due to adhesion of water or like to a cut end portion of the lead exposed from the mold resin of the circuit package. A thermal flow meter 300 of the present invention is a thermal flow meter having a circuit package 400 formed by mounting a detection element 518 on leads 544 and 545 supported by a support frame 512, sealing with a mold resin, and cutting off the support frame 512, wherein cut end portions 544a and 545a of the leads 544 and 545 exposed from the mold resin of the circuit package 400 by cutting off the support frame 512 is covered by a covering portion 371.

Abstract: The invention provides a thermal flow meter which can precisely sense the measurement target gas even in the case that the resin housing and the cover are welded by the laser. The invention is a thermal flow meter (300) having a bypass passage for flowing measurement target gas (30) which is taken from a main passage (124), and an air flow sensing portion (602) for measuring a flow rate of the measurement target gas (30) by carrying out heat transfer in relation to the measurement target gas (30) which flows in the bypass passage. A concave trench (741) is formed in such a manner that a part of an interface (792) between an end face of a bypass passage forming wall (390) including a weld portion (792) and a rear face of a cover (303) is positioned in a wall surface of the concave trench (741).

Abstract: In order to provide a thermal-type flowmeter highly accurate, with high reliability, and simple in construction, while being available at a lower price, a thermal-type flowmeter as proposed includes a sub-path that takes in a fluid under measurement; a sensor element that measures a flow-rate of the fluid under measurement in the sub-path; a temperature detection element that detects a temperature of the fluid under measurement; a drive circuit that controls a heating temperature of the sensor element; and a protection circuit that protects the drive circuit from noise, a cavity being formed on a substrate of the sensor element, an exothermic resistor being provided on a thin-film part on the cavity through the intermediary of an electrically insulating film, and a flow rate being detected on the basis of temperature distribution in the thin-film part.

Abstract: Provided is a thermal flow meter to improve the measurement accuracy of a temperature detector provided in a thermal flow meter. The thermal flow meter includes a bypass passage through which a measurement target gas 30 flowing through a main passage flows, and a circuit package 400 which includes a measurement circuit for measuring a flow rate of the measurement target gas 30 flowing through the bypass passage and a temperature detecting portion 452 for detecting a temperature of the measurement target gas. The circuit package 400 includes a circuit package body which is molded by a resin to internally envelope the measurement circuit and a protrusion 424 molded by the resin. The temperature detecting portion 452 is provided in the leading end portion of the protrusion 424, and at least the leading end portion of the protrusion protrudes to the outside from a housing 302.

Abstract: An object of the present invention is to provide a thermal airflow sensor with high detection accuracy. In achieving the above object, this invention provides a thermal flow sensor including: a flow rate detection element that has a diaphragm formed by processing a semiconductor substrate, a heating resistor provided on the diaphragm, and resistance temperature detectors installed upstream and downstream of the heating resistor; and a support member that adhesively holds the flow rate detection element with a sheet adhesive interposed therebetween. The support member includes a communicating hole of which one end has an opening to a cavity provided on the back side of the diaphragm. The sheet adhesive has a ventilating hole formed in an opening area of the communicating hole in the support member.

Abstract: An object of the invention is to provide a thermal flow meter which can simplify the manufacturing process and has high measurement accuracy. In the thermal flow meter of the invention, a circuit package 400 includes a passage portion 605 in which an air flow sensing portion 602 is arranged and a processing unit 604 in which a circuit is arranged, and is fixed to a fixing portion 372 integrally formed with the circuit package 400, whereby the passage portion 605 of the circuit package 400 is held in a bypass passage, and at least a portion of an end 401 spaced apart from a fixing wall 372 of the passage portion 605 of the circuit package 400 is exposed in the bypass passage.

Abstract: A thermal flow meter capable of measuring flow rates of a gas flowing in a forward direction and a backward direction with a high degree of accuracy is provided. A thermal flow meter 300 according to the present invention includes a bypass passage configured to retrieve and flow a measurement target gas 30 received from a main passage 124 and a flow rate measurement circuit 601 configured to measure a flow rate by performing heat transfer with the measurement target gas flowing in the bypass passage.

Abstract: To improve measurement accuracy of a thermal flow meter. The present invention provides a thermal flow meter, in which a protrusion 356 having an orifice surface 503 and a recovery surface 505 is provided on a wall surface 501 of a bypass passage, an intersection line 506 between the orifice surface 503 and the wall surface 501 is arranged in an upstream side from an upstream side end 401 of a circuit package 400, an intersection line 507 between the recovery surface 505 and the wall surface 501 is arranged in a downstream side from a downstream side end 402 of the circuit package 400, and an apex 504 of the protrusion 356 is arranged in a downstream side from a heat transfer surface of an air flow sensing portion 602 and in an upstream side from the downstream side end 402 of the circuit package 400.

Abstract: The present invention provides a thermal flow meter 300 which reduces a stress applied from a fixing portion 3721, which is used to hold and fix a circuit package 400 with respect to a housing 302, to the circuit package 400 and has high reliability. In the thermal flow meter of the invention, the circuit package 400 embedded with a flow rate measurement circuit is formed through a first resin molding process, the fixing portion 3721 is formed along with the housing 302 through a second resin molding process, and the circuit package 400 is enveloped by the fixing portion 3721, whereby the circuit package 400 is held by and fixed to the housing 302. In order to reduce the influence of a stress, generated based on a temperature change of the fixing portion 3721, on the circuit package 400, the fixing portion 3721 is constituted of a thick portion 4714 and a thin portion 4710.

Abstract: A thermal flow meter which has a high reliability and has a gas temperature detecting portion is obtained.

Abstract: The present invention aims to provide a thermal flow meter capable of avoiding pollutants guided to an outer circumference side of the bypass passage by virtue of a centrifugal force or particle or liquid pollutants that are not centrifugally separated from reaching a heat transfer surface of an air flow sensing portion and obtaining high measurement accuracy. In the thermal flow meter of the present invention, the bypass passage has an upstream side curved path 390 formed in a curved shape along an unique plane at least in an upstream side from an air flow sensing portion 602 in a flow direction of the measurement target gas 30, and a branching wall 378 formed from a downstream side of the upstream side curved path 390 to a downstream side of the air flow sensing portion 602.

Abstract: To obtain a thermal flow meter capable of providing thermal insulation without degrading responsiveness of a temperature detection element.

Abstract: Provided is a thermal flow meter through which a measurement with high accuracy and has a discharge function. In a thermal flow meter 300 of the invention, a part of a measurement target gas 30 flowing through the main passage 124 flows into a bypass passage. A drainage passage 3528 is provided in the bypass passage to communicate a bypass passage 4232 on the inlet port (between the inlet port 350 and the measurement surface 430 serving as the air flow sensing portion) and a bypass passage 4234 on the outlet port (between the measurement surface 430 serving as the air flow sensing portion and the outlet port 352). The drainage passage 3528 includes a through hole 3512. The through hole 3512 includes an inlet port 3542 which penetrates a wall surface 4212 forming the bypass passage 4232 on the inlet port and is opened in the bypass passage 4232 on the inlet port, and an outlet port 3544 which is opened in a rear surface 4213 of the wall surface.

Abstract: Technology capable of suppressing performance variation for each flow sensor and enhancing the performance is provided. According to a flow sensor of an embodiment, a local cavity CAV is provided on an upper surface SUR (MR) of a resin MR to generate an eddying current in a counterclockwise direction, so that an advancing direction of gas (air) that collided to an exposed side surface of a semiconductor chip CHP1 can be changed to an eddying direction instead of a direction toward an upper side of the semiconductor chip CHP1 differing by 90 degrees. Therefore, according to the flow sensor of the embodiment, the flow of the gas (air) at an upper side of the flow sensing unit FDU can be stably made smooth without being disturbed, whereby a flow sensing accuracy in the flow sensing unit FDU can be enhanced.