Abstract: A diagnostic function of a humidity sensor is exposed to the outside and the humidity sensor is likely to deteriorate. An aspect of the present invention includes: a capacitance-voltage conversion circuit which includes a plurality of reference capacitors having different pieces of capacitance and a switch which switches the reference capacitors and outputs a voltage according to the capacitance of a humidity sensor; and a diagnosis unit which compares an output voltage of the capacitance-voltage conversion circuit with a reference voltage obtained from a reference characteristic of the humidity sensor and diagnoses the humidity sensor based on a comparison result. Also, the diagnosis unit changes the output voltage by changing the capacitance of the capacitance-voltage conversion circuit using the switch in a state in which the output voltage of the capacitance-voltage conversion circuit is within a certain range and compares the changed output voltage with the reference voltage.

Abstract: A flow-volume detecting apparatus including a flow-volume detecting unit which measures a flow volume of a measured fluid, a flow-volume state determining unit which determines a flow-volume state of the measured fluid based on an output from the flow-volume detecting unit. The flow-volume detecting apparatus further including a plurality of filters which process a flow-volume signal, and a filter selecting unit which selects a filter that processes the flow-volume signal, wherein the filter selecting unit selects the filter that processes the flow-volume signal according to the flow-volume state determined by the flow-volume state determining unit.

Abstract: Provided is a physical quantity measurement device capable of reducing a frequency analysis error of a gas flow rate as compared with the related art. A physical quantity measurement device 20 includes a flow rate sensor 205 and a signal processing unit 260. The signal processing unit 260 has a buffer 261, an offset adjustment unit 262, a gain calculation unit 263, a correction calculation unit 264, and a frequency analysis unit 265. The buffer 261 stores a flow rate data based on an output signal of the flow rate sensor 205 for a predetermined period. The offset adjustment unit 262 adjusts the zero point of the flow rate waveform. The gain calculation unit 263 calculates a correction gain of the flow rate waveform whose zero point has been adjusted. The correction calculation unit 264 performs the correction by multiplying the flow rate waveform whose zero point has been adjusted by the correction gain.

Abstract: A compact physical quantity detecting device is provided since it is possible to lower the mounting height of a chip package by accommodating the chip package in a notched board. In the physical quantity detecting device of the present invention, a part in a thickness direction of a support body on which a flow rate detection unit and a processing unit are mounted is accommodated in a notch provided in a printed board.

Abstract: A decrease in the accuracy after switching of the heating state can be reduced. The physical quantity detecting device includes: a flow rate detecting unit configured to include a heating element to measure a flow rate of a fluid to be measured; a heating element control unit configured to switch a control state of the heating element to any one of a heating state and a heating suppression state; and a signal processing unit configured to process a measured value of the flow rate detecting unit. When the heating element control unit switches the control state, the signal processing unit processes an estimated value determined based on a measured value of the flow rate detecting unit before the switching for a predetermined period immediately after the switching.

Abstract: Provided is a physical quantity measurement device capable of reducing a frequency analysis error of a gas flow rate as compared with the related art. A physical quantity measurement device 20 includes a flow rate sensor 205 and a signal processing unit 260. The signal processing unit 260 has a buffer 261, an offset adjustment unit 262, a gain calculation unit 263, a correction calculation unit 264, and a frequency analysis unit 265. The buffer 261 stores a flow rate data based on an output signal of the flow rate sensor 205 for a predetermined period. The offset adjustment unit 262 adjusts the zero point of the flow rate waveform. The gain calculation unit 263 calculates a correction gain of the flow rate waveform whose zero point has been adjusted. The correction calculation unit 264 performs the correction by multiplying the flow rate waveform whose zero point has been adjusted by the correction gain.

Abstract: Provided is a thermal-type flowmeter which can prevent a reduction of flow rate accuracy and reliability, and an increase of cost of the thermal-type flowmeter compared to the related art, and can add a function of an electrostatic scattering mechanism. The thermal-type flowmeter of the present invention includes a sub-passage into which part of a measurement target gas flowing in a main passage is taken, a flow rate detection element of a flow measurement unit which is disposed in the sub-passage, a circuit package which supports the flow rate detection element, and a substrate to which the circuit package is fixed. The flow rate detection element includes a detection surface to detect a flow rate of the measurement target gas. The detection surface is disposed to face the circuit substrate.

Abstract: A physical quantity detecting device includes a circuit board having a first support portion with a physical quantity detecting element, a second support portion with a temperature detecting element, and a housing molded by injection molding, the housing supporting the circuit board. The physical quantity detecting element is configured to detect a physical quantity of fluid and the temperature detecting element is configured to detect a temperature of the fluid. The second support portion protrudes from an edge of the circuit and has a third support portion supporting the second support portion in connection with the housing. The third support portion is located on a same side as the leading end portion, with respect to a base end portion, and located on a same side as the base end portion, with respect to an implementation portion on which the temperature detecting element is implemented.

Abstract: An object of the present invention is to provide a gas sensor device capable of detecting a temporal change with high accuracy and maintaining measurement accuracy over a long period under a temperature environment susceptible to a complicated and wide range of change. The gas sensor device includes: heat insulating films 8a and 8b formed on a substrate 2; a first heater 3 provided on the heat insulating films 8a and 8b and configured to measure physical quantity of gas; and a reference resistor 4 formed in a resistive layer same as the first heater and formed on the heat insulating films 8a and 8b. The gas sensor device further includes a second heater 5 that simultaneously heats the first heater 3 and the reference resistor 4.

Abstract: It is possible to reduce a degradation in accuracy after switching of a heating state or after change of the flow rate.

Abstract: To obtain a physical quantity detection apparatus that can reduce the outer shape of a housing in size. A physical quantity detection apparatus 300 detects a plurality of physical quantities of gas 30 to be measured flowing in a main passage 124. The physical quantity detection apparatus 300 has a housing 302 disposed in the main passage 124, a circuit substrate 400 insert molded in the housing 302, and a plurality of detection sensors 452, 453, 454, 455, and 456 each mounted on each of one face and the other face of the circuit substrate 400.

Abstract: A sensor device includes a detection resistor having a resistance value changing according to a physical quantity and a reference resistor compared with the detection resistor, the reference resistor is configured by electrically connecting a first resistance circuit and a second resistance circuit. The first resistance circuit includes a first and a second resistive element having positive and negative resistance temperature coefficients, respectively, which are electrically connected. The second resistance circuit includes a third and a fourth resistive elements having a positive and a negative resistance temperature coefficient, respectively, which are electrically connected. The first resistance circuit is configured to generate a first deviation to either the positive or negative side with respect to a temperature change, and the second resistance circuit is configured to generate a second deviation to the side opposite to the positive or negative side where the first deviation is generated.

Abstract: Provided is a thermal-type flowmeter which can prevent a reduction of flow rate accuracy and reliability, and an increase of cost of the thermal-type flowmeter compared to the related art, and can add a function of an electrostatic scattering mechanism. The thermal-type flowmeter of the present invention includes a sub-passage into which part of a measurement target gas flowing in a main passage is taken, a flow rate detection element of a flow measurement unit which is disposed in the sub-passage, a circuit package which supports the flow rate detection element, and a substrate to which the circuit package is fixed. The flow rate detection element includes a detection surface to detect a flow rate of the measurement target gas. The detection surface is disposed to face the circuit substrate.

Abstract: A compact physical quantity detecting device is provided since it is possible to lower the mounting height of a chip package by accommodating the chip package in a notched board. In the physical quantity detecting device of the present invention, a part in a thickness direction of a support body on which a flow rate detection unit and a processing unit are mounted is accommodated in a notch provided in a printed board.

Abstract: The purpose of the present invention is to reduce a load of preventing dew condensation, and to provide a highly reliable humidity detection device. In order to achieve the purpose, this humidity detection device is provided with: a humidity sensor having a humidity detection unit and a temperature detection unit; a heating resistor that heats the humidity sensor; and a heating control unit that controls a heating temperature of the heating resistor. The humidity detection device is characterized in having a target temperature storage unit that stores target temperatures of the heating resistor, said target temperatures having been determined corresponding to temperatures and humidities.

Abstract: The purpose is to improve the measurement accuracy of a thermal air flow meter. The device has: an auxiliary passage for entraining a portion of a fluid being measured; a sensor chip arranged in the auxiliary passage, for measuring the flow rate of the fluid being measured; an electronic component having an internal resistor, for converting the fluid flow rate detected by the sensor chip to an electrical signal; and a substrate on which the sensor chip and the electronic component are mounted. The substrate is covered by a filler material, on the surface of which the electronic component is mounted.

Abstract: An object of the present invention is to provide a compact air flow rate measuring device with improved stain resistance. A physical quantity detecting device of the present invention includes: a semiconductor element having a flow rate detection unit 205; a circuit board 207 supporting the semiconductor element; and a conductive cover 202 fixing the circuit board 207, and the semiconductor element is fixed to the circuit board 207 such that the flow rate detection unit 205 faces the cover 202.

Abstract: An air flow rate measurement device capable of suppressing disturbance of a flow of measured gas and reducing a characteristic influence due to water droplets flowing with intake air is realized. An edge 800 of the upstream side where air flows in a circuit board 400 on which a flow rate detection portion 602 is mounted is provided with a segmentation portion 801 to be a semicircular notch structure to segment the edge 800. Water droplets flowing with measured gas 30 can be captured by the segmentation portion 801 to inhibit the water droplets from arriving at the flow rate detection portion 602.

Abstract: A physical quantity detection device includes: a housing; a circuit board; a resin material which covers the circuit board; a cover which forms a circuit chamber in which the circuit board is disposed and a flow path through which a gas to be measured passes together with the housing; and a conductor which is disposed to be exposed to the flow path, in which the conductor and the circuit board are electrically connected to each other.

Abstract: A decrease in the accuracy after switching of the heating state can be reduced. The physical quantity detecting device includes: a flow rate detecting unit configured to include a heating element to measure a flow rate of a fluid to be measured; a heating element control unit configured to switch a control state of the heating element to any one of a heating state and a heating suppression state; and a signal processing unit configured to process a measured value of the flow rate detecting unit. When the heating element control unit switches the control state, the signal processing unit processes an estimated value determined based on a measured value of the flow rate detecting unit before the switching for a predetermined period immediately after the switching.