Abstract: A pressure sensor includes a diaphragm of a thin plate shape, the diaphragm forming part of a wall surface of a pressure chamber into and out from which a measurement target fluid flows. Multiple recesses are formed in the diaphragm on a side in contact with the measurement target fluid, and an interval between adjacent two of the multiple recesses is 10 ?m or less.

Abstract: A pressure sensor includes a movable electrode formed in a movable region of a diaphragm, and a fixed electrode formed opposite to the movable electrode. A pressure receiving surface of the diaphragm is held in an inactive state. The inactive pressure receiving surface of the diaphragm is in a state in which molecules of gas to be measured are hard to absorb onto the pressure receiving surface. The pressure receiving surface of the diaphragm can be made inactive by predetermined surface treatment. A layer for making the pressure receiving surface of the diaphragm inactive is formed by the surface treatment, and the pressure receiving surface of the diaphragm is held inactive with the presence of the layer.

Abstract: A pressure sensor includes a diaphragm of a thin plate shape, the diaphragm forming part of a wall surface of a pressure chamber into and out from which a measurement target fluid flows. Multiple recesses are formed in the diaphragm on a side in contact with the measurement target fluid, and an interval between adjacent two of the multiple recesses is 10 ?m or less.

Abstract: An electrode pair that forms a pressure-sensitive capacitance Cx in the central portion of a diaphragm is called a first electrode pair (pressure-sensing electrode pair), and another electrode pair that forms a reference capacitance Cr in the circumferential portion of the diaphragm is called a second electrode pair (reference electrode pair). The ratio ?Cx/?Cr of a change ?Cx in the pressure-sensitive capacitance Cx, which is obtained from the pressure-sensing electrode pair at the time of evacuation, to a change ?Cr in the reference capacitance Cr, which is obtained from the reference electrode pair at the time of evacuation, is calculated as an index for malfunction detection ?. Then, the index for malfunction detection ? thus calculated is compared with the reference value ?ref, which represents the index observed during normal operation, and whether deformation due to a cause other than pressure has been generated in the diaphragm is determined.

Abstract: A pressure sensor includes a movable electrode formed in a movable region of a diaphragm, and a fixed electrode formed opposite to the movable electrode. A pressure receiving surface of the diaphragm is held in an inactive state. The inactive pressure receiving surface of the diaphragm is in a state in which molecules of gas to be measured are hard to absorb onto the pressure receiving surface. The pressure receiving surface of the diaphragm can be made inactive by predetermined surface treatment. A layer for making the pressure receiving surface of the diaphragm inactive is formed by the surface treatment, and the pressure receiving surface of the diaphragm is held inactive with the presence of the layer.

Abstract: A pressure introducing chamber is provided with a baffle plate which is positioned with one surface thereof facing in a direction orthogonal to a direction of travel of a measured medium introduced through a pressure introducing hole into the pressure introducing chamber. A first distance between a pressure receiving surface of a sensor diaphragm and an inner surface of the pressure introducing chamber facing the pressure receiving surface and a second distance between the pressure receiving surface of the sensor diaphragm and the other surface of the baffle plate facing the pressure receiving surface are both smaller than a mean free path of the measured medium in the entire region of the pressure receiving surface of the sensor diaphragm.

Abstract: A base plate has pressure introducing holes at positions facing a diaphragm support portion. A thickness portion (thick portion) of the diaphragm support portion and a sensor base joined to the diaphragm support portion thus serves as a heat dissipating or absorbing portion and hinders the transfer of thermal energy of a measured medium to a sensor diaphragm.

Abstract: A temperature difference calculation unit determines a temperature difference between a temperature measured by a first temperature measurement mechanism and a temperature measured by a second temperature measurement mechanism. The first temperature measurement mechanism is disposed on an outer wall surface of an inner container at a position corresponding to an element-arrangement-side space in the inner container. The second temperature measurement mechanism is disposed on an outer peripheral surface of a heater. The heater is disposed outside an outer container that accommodates the inner container and positioned on a wall surface of the outer container.

Abstract: A state determination unit compares an output value obtained by a measuring unit with a reference characteristic value that serves as a reference, counts the number of times an excessive pressure application state occurs in which the output value is determined to be equal to or larger than the reference characteristic value, and determines whether the number of times reaches an upper limit that is set. An alarm output unit outputs an alarm when the state determination unit determines that the number of times the output value is equal to or larger than the reference characteristic value reaches the set upper limit.

Abstract: An electrode pair that forms a pressure-sensitive capacitance Cx in the central portion of a diaphragm is called a first electrode pair (pressure-sensing electrode pair), and another electrode pair that forms a reference capacitance Cr in the circumferential portion of the diaphragm is called a second electrode pair (reference electrode pair). The ratio ?Cx/?Cr of a change ?Cx in the pressure-sensitive capacitance Cx, which is obtained from the pressure-sensing electrode pair at the time of evacuation, to a change ?Cr in the reference capacitance Cr, which is obtained from the reference electrode pair at the time of evacuation, is calculated as an index for malfunction detection ?. Then, the index for malfunction detection ? thus calculated is compared with the reference value ?ref, which represents the index observed during normal operation, and whether deformation due to a cause other than pressure has been generated in the diaphragm is determined.

Abstract: A pressure change measuring unit causes a temperature control unit to operate and vary the temperature of a sensor chip in a predetermined temperature range, and measures changes in pressure value output from the sensor chip whose temperature is being varied. A temperature characteristic calculating unit calculates a temperature characteristic of the sensor chip from changes in the temperature of the sensor chip caused by the operation of the temperature control unit and changes in pressure value measured by the pressure change measuring unit.

Abstract: A temperature difference calculation unit determines a temperature difference between a temperature measured by a first temperature measurement mechanism and a temperature measured by a second temperature measurement mechanism. The first temperature measurement mechanism is disposed on an outer wall surface of an inner container at a position corresponding to an element-arrangement-side space in the inner container. The second temperature measurement mechanism is disposed on an outer peripheral surface of a heater. The heater is disposed outside an outer container that accommodates the inner container and positioned on a wall surface of the outer container.

Abstract: A pressure introducing chamber is provided with a baffle plate which is positioned with one surface thereof facing in a direction orthogonal to a direction of travel of a measured medium introduced through a pressure introducing hole into the pressure introducing chamber. A first distance between a pressure receiving surface of a sensor diaphragm and an inner surface of the pressure introducing chamber facing the pressure receiving surface and a second distance between the pressure receiving surface of the sensor diaphragm and the other surface of the baffle plate facing the pressure receiving surface are both smaller than a mean free path of the measured medium in the entire region of the pressure receiving surface of the sensor diaphragm.

Abstract: A base plate has pressure introducing holes at positions facing a diaphragm support portion. A thickness portion (thick portion) of the diaphragm support portion and a sensor base joined to the diaphragm support portion thus serves as a heat dissipating or absorbing portion and hinders the transfer of thermal energy of a measured medium to a sensor diaphragm.

Abstract: A pressure change measuring unit causes a temperature control unit to operate and vary the temperature of a sensor chip in a predetermined temperature range, and measures changes in pressure value output from the sensor chip whose temperature is being varied. A temperature characteristic calculating unit calculates a temperature characteristic of the sensor chip from changes in the temperature of the sensor chip caused by the operation of the temperature control unit and changes in pressure value measured by the pressure change measuring unit.

Abstract: A state determination unit compares an output value obtained by a measuring unit with a reference characteristic value that serves as a reference, counts the number of times an excessive pressure application state occurs in which the output value is determined to be equal to or larger than the reference characteristic value, and determines whether the number of times reaches an upper limit that is set. An alarm output unit outputs an alarm when the state determination unit determines that the number of times the output value is equal to or larger than the reference characteristic value reaches the set upper limit.

Abstract: To enable early detection of abnormal states including accumulation on a pressure sensor, a characteristic measuring portion obtains a change in an output of a pressure sensor in a state in which the temperature of a sensor chip is changed by operation of a temperature controlling portion and thereby obtains a sensor characteristic indicating the change in the output. A state determination portion determines an abnormal state of a diaphragm by comparing the sensor characteristic obtained by the characteristic measuring portion with a reference characteristic, used as a reference, stored in a reference value storing portion.

Abstract: A humidity sensor according to the present examples include a sensor portion for detecting humidity in the ambient environment, and a power supply portion for applying an AC voltage to the sensor portion, wherein the sensor portion is structured so as to have an impedance that is higher than a sensor portion of a conventional humidity sensor. As a result, it is possible to reduce the amount of power consumed in the sensor portion when compared to that of a conventional humidity sensor. Doing so makes it possible to reduce the amount of electrical power consumed in the humidity sensor as a whole in the present invention, including the sensor portion, when compared to that of a conventional humidity sensor.

Abstract: A humidity sensor according to the present examples include a sensor portion for detecting humidity in the ambient environment, and a power supply portion for applying an AC voltage to the sensor portion, wherein the sensor portion is structured so as to have an impedance that is higher than a sensor portion of a conventional humidity sensor. As a result, it is possible to reduce the amount of power consumed in the sensor portion when compared to that of a conventional humidity sensor. Doing so makes it possible to reduce the amount of electrical power consumed in the humidity sensor as a whole in the present invention, including the sensor portion, when compared to that of a conventional humidity sensor.

Abstract: An electrostatic capacitive sensor able to detect a first electrostatic capacitance and a second electrostatic capacitance, comprising: a member wherein is formed a movable diaphragm that has electrical conductivity; a thin-film electrode that forms a first electrostatic capacitance with the diaphragm; a thin-film electrode that forms a second electrostatic capacitance with the diaphragm; an upper member that is provided so as to form a space between itself and the top face of the diaphragm; and a tower member that is provided so as to form a second space between itself and the bottom face of the diaphragm; wherein: a gas is filled into the space and another gas, which has a coefficient of thermal expansion different from that of the gas, is filled into the second space.