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 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 sensor substrate includes an insulating substrate including a plurality of inorganic particles formed of an insulator in contact with each other and glass, and a wiring conductor disposed on the insulating substrate. The plurality of inorganic particles and the glass are in contact with the wiring conductor, and the glass is disposed at a position between the plurality of inorganic particles and the wiring conductor, and a contact portion between the plurality of inorganic particles and the wiring conductor is larger than a contact portion between the glass and the wiring conductor in a longitudinal sectional view.

Abstract: A sensor substrate includes an insulating substrate including a plurality of inorganic particles formed of an insulator in contact with each other and glass, and a wiring conductor disposed on the insulating substrate. The plurality of inorganic particles and the glass are in contact with the wiring conductor, and the glass is disposed at a position between the plurality of inorganic particles and the wiring conductor, and a contact portion between the plurality of inorganic particles and the wiring conductor is larger than a contact portion between the glass and the wiring conductor in a longitudinal sectional view.