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: A thermal-type flowmeter includes a chip package. The chip package is formed through encapsulation with a resin of a sensor element, a drive circuit, a metal lead frame adapted to have mounted thereon the sensor element and the drive circuit, and a temperature detecting element. The chip package has an exposed structure in which a surface of the sensor element having the diaphragm is exposed. The temperature detecting element is mounted on the lead frame via an electrically conductive member.

Abstract: In order to provide a flow measuring device high in thermal responsiveness, the flow measuring device includes a temperature detecting element 2 for temperature detection, and a conductive metal lead frame 3 that supports and fixes the temperature detecting element. Of the metal lead frame, a part of the metal lead frame mounted with the temperature detecting element has a portion which is thinner than the thickness of the other metal lead frame or narrower than the width of the other metal lead frame.

Abstract: In order to provide a thermal flow meter capable of preventing adherence of contaminants to an air flow sensing portion, the thermal flow meter (300) of the invention includes a bypass passage for flowing a measurement target gas (30) received from a main passage (124) and an air flow sensing portion (602) for measuring a flow rate of the measurement target gas (30) by performing heat transfer with the measurement target gas (30) flowing through the bypass passage through a heat transfer surface (437). The air flow sensing portion (602) is provided to be exposed to an exposed surface (402) arranged along a flow direction of the measurement target gas (30) inside the bypass passage is embedded, the mount support surface (402) has a stage (407) formed to surround a periphery of the air flow sensing portion (602), and an inner portion surrounded by the stage protrudes more than an outer portion of the stage.

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: 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: An object of the present invention is to provide a thermal-type air flow meter with a high measurement accuracy by reducing influence of a thermal stress generated in a resistor in an LSI while securing a high positioning accuracy flow rate detection unit.

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: 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 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: 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: Provided is a thermal flow meter to improve the measurement accuracy of a temperature detector provided in a thermal flow meter 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: The present invention has been made to improve measurement accuracy of a thermal flow meter. In the thermal flow meter according to the invention, a circuit package (400) that measures a flow rate is molded in a first resin molding process. In a second resin molding process, a housing (302) having an inlet trench (351), a bypass passage trench on frontside (332), an outlet trench (353), and the like are formed through resin molding, and an outer circumferential surface of the circuit package (400) produced in the first resin molding process is enveloped by a resin in the second resin molding process to fix the circuit package (400) to the housing (302).

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: It is an object of the present invention to improve a measurement accuracy of a thermal flowmeter. 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: In order to provide a thermal flow meter for improving workability of a flow rate measurement device having a temperature measurement function for the measurement target gas and measurement accuracy for measuring a temperature, the thermal flow meter is structured such that a flow rate measurement circuit package having a protrusion for measuring a gas temperature is formed through resin molding. An inlet port opened to the upstream side of the measurement target gas is formed, a protrusion is arranged inside the inlet port, an inlet port and an outlet port are formed in the front and rear covers along the protrusion, and the measurement target gas received from the inlet port flows along the protrusion. Since the measurement target gas subjected to the measurement flows along the protrusion, it is possible to reduce influence of the heat from other heat resources and improve measurement accuracy.

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: In order to provide a method of manufacturing a thermal type flowmeter that is capable of reducing deformation of a semiconductor chip, which is caused by molding, a method of manufacturing a thermal type flowmeter is provided that includes a circuit package of a resin-molded semiconductor chip. The method includes resin-molding the semiconductor chip in a state in which a mold is pressed against a heat transfer surface that is provided on a surface of the semiconductor chip and a pressed surface that is set on the surface of the semiconductor chip at a position separate from the heat transfer surface.

Abstract: The present invention has been made to improve measurement accuracy of a thermal flow meter. In the thermal flowmeter according to the invention, a circuit package (400) that measures a flow rate is molded in a first resin molding process. In a second resin molding process, a housing (302) having an inlet trench (351), a bypass passage trench on frontside (332), an outlet trench (353), and the like are formed through resin molding, and an outer circumferential surface of the circuit package (400) produced in the first resin molding process is enveloped by a resin in the second resin molding process to fix the circuit package (400) to the housing (302).

Abstract: A thermal flow meter has improved measurement accuracy due to the shape of a circuit package. The circuit package has a measurement surface and a backside of a measurement surface of a rear surface thereof is located in a bypass passage, the bypass passage being configured to allow a measurement target gas to flow therein dividing the measurement target gas into a flow path at a side of the measurement surface and a flow path at a side of the backside of measurement surface of a rear surface thereof. An inflow-side end surface of the circuit package has different shapes at the side of the measurement surface and at the side of the backside of the measurement surface.