Abstract: A first shield case covers an amplifier on a second surface of a wiring board. A sensor on a first surface of the board includes a light emitter that illuminates, with light, an illumination target having a space in which a fluid flows, a light receiver that receives coherent light including light scattered by the target in the light from the light emitter and outputs an output signal corresponding to intensity of the coherent light, and a package accommodating the emitter and the receiver and including a first wire. The amplifier amplifies the output signal. The calculator calculates a value indicating a flow state of the fluid based on the output signal amplified by the amplifier. The first wire surrounds the emitter and the receiver in a plan or transparent plan view of the package. The first wire and the first shield case are electrically connected to a ground wire.

Abstract: A measurement device includes a light emitter, a light receiver, an identifier, and a calculator. The light emitter irradiates, with light, an irradiation target having a fluid flowing in an internal space of the irradiation target. The light receiver receives coherent light including light scattered by the irradiation target and outputs an output signal corresponding to an intensity of the coherent light. The identifier obtains a characteristic quantity indicating a characteristic of a signal waveform of the output signal, and identifies, based on the obtained characteristic quantity, an abnormal signal portion of the output signal. The calculator calculates, based on a signal portion of the output signal other than the abnormal signal portion, a flow state value indicating a flow state of the fluid.

Abstract: A measurement module for measuring a fluid on a flow path defined in an internal space of a flow path section includes a sensor and a reflector. The sensor includes a light emitter and a light receiver. The sensor and the reflector are placeable into a first state in which the sensor and the reflector face each other across the flow path. In the first state, the light receiver receives, in response to the light emitter irradiating the flow path section with light, light scattered by the flow path section, light transmitted through the flow path section and scattered by the fluid on the flow path, and light transmitted through the flow path section and the fluid on the flow path and reflected by the reflector.

Abstract: A flow rate-velocity sensor device includes a package including a light receiver and a light emitter, a transparent substrate including a light shield, and a flow rate-velocity calculator. The flow rate-velocity calculator includes a receiver, a correction unit, an arithmetic unit, and a transmitter. The receiver receives data on a first power spectrum. The correction unit corrects the data received by the receiver to calculate a second power spectrum. The arithmetic unit calculates at least one of a flow rate or a flow velocity from the second power spectrum calculated by the correction unit. The transmitter transmits, to an external unit, at least one of the flow rate or the flow velocity calculated by the arithmetic unit.

Abstract: A measurement device includes a light emitter, a light receiver, an extractor, and a processor. The light emitter illuminates an illumination target having an internal space through which a fluid flows. The light receiver receives coherent light including light scattered by the illumination target and outputs a signal corresponding to intensity of the coherent light. The extractor extracts a direct-current component from the signal output from the light receiver at a temporal change in strength of the signal. The processor calculates a calculation value for a flow state of the fluid by performing a process on the signal output from the light receiver. The process includes correction using a value of signal strength of the direct-current component and calculation of a frequency spectrum for the signal at the temporal change in the signal strength.

Abstract: A measurement device includes a light emitter, a light receiver, an amplifier, and a computation processor. The light emitter irradiates, with light, an irradiation target having an internal space through which a fluid flows. The light receiver receives coherent light including light scattered by the irradiation target and outputs a signal corresponding to intensity of the coherent light. The amplifier amplifies the signal output from the light receiver. The computation processor calculates a first frequency spectrum of signal strength for each frequency with respect to a temporal strength change in the signal amplified by the amplifier, and calculates a calculation value on a flow state of the fluid with a computation including division using a first value and a second value. The first value is a value of a frequency based on the first frequency spectrum. The second value is a value of strength based on the first frequency spectrum.

Abstract: A flow rate-velocity sensor device includes a package including a light receiver and a light emitter, a transparent substrate including a light shield, and a flow rate-velocity calculator. The flow rate-velocity calculator includes a receiver, a correction unit, an arithmetic unit, and a transmitter. The receiver receives data on a first power spectrum. The correction unit corrects the data received by the receiver to calculate a second power spectrum. The arithmetic unit calculates at least one of a flow rate or a flow velocity from the second power spectrum calculated by the correction unit. The transmitter transmits, to an external unit, at least one of the flow rate or the flow velocity calculated by the arithmetic unit.