The present disclosure relates to the field of measuring three-dimensional shapes of 3D structures, in particular wind turbine structures like wind turbine blades, using optical fibre strain sensors, namely Fibre Bragg Gratings, FBGs. It is disclosed a device and corresponding method for measuring a three-dimensional shape of a structure by being slidably coupled to the structure such that the deformation of the structure, except lengthening or shortening, causes a corresponding deformation of the device, the device comprising: a pliant beam; three or more optical fibres arranged lengthwise in parallel within said beam and having a transversal distance between said fibres in at least two different transversal directions; wherein said optical fibres comprise a plurality of sensor regions distributed along said optical fibres, wherein each said sensor region comprises a Fibre Bragg Grating in each of the optical fibres.

A variable diaphragm is provided. The variable diaphragm includes: first and second substrates opposite to each other; a light detector on a side of the first substrate distal to the second substrate, and configured to detect an intensity of incident light and generate a first signal; an electrowetting microfluid medium layer between the first and second substrates, and including transparent and opaque fluid mediums immiscible with each other, wherein an aperture of the variable diaphragm is formed by the transparent fluid medium, and one of the transparent and opaque fluid mediums is conductive; and a driving electrode between the first and second substrates, and configured to receive a driving voltage corresponding to the first signal and for driving the electrowetting microfluid medium layer, so as to change an area of an orthographic projection of the opaque fluid medium fluid medium on the second substrate, thereby changing a diameter of the aperture.

Pressure sensors having ring-tensioned membranes are disclosed. A tensioning ring is bonded to a membrane in a manner that results in the tensioning ring applying a tensile force to the membrane, flattening the membrane and reducing or eliminating defects that may have occurred during production. The membrane is bonded to the sensor housing at a point outside the tensioning ring, preventing the process of bonding the membrane to the housing from introducing defects into the tensioned portion of the membrane. A dielectric may be introduced into the gap between the membrane and the counter electrode in a capacitive pressure sensor, resulting in an improved dynamic range.

A pressure sensing apparatus comprises an elongate first sensor device in a beam configuration supported at at least one longitudinal end by a rigid support structure and having a deflectable portion. A chamber is disposed adjacent a first, internally-facing, face of the first sensor device. An envelope hermetically seals the first sensor device and the chamber from an ambient environment external to the pressure sensing apparatus. The envelope comprises a flexible membrane disposed over and coupled to a second, externally-facing, face of the first sensor device and extending along at least one or two sides of the first sensor device and the chamber. The sensor device may be a surface acoustic wave device coupled to an RF antenna.

Pressure sensors having ring-tensioned membranes are disclosed. A tensioning ring is bonded to a membrane in a manner that results in the tensioning ring applying a tensile force to the membrane, flattening the membrane and reducing or eliminating defects that may have occurred during production. The membrane is bonded to the sensor housing at a point outside the tensioning ring, preventing the process of bonding the membrane to the housing from introducing defects into the tensioned portion of the membrane. A dielectric may be introduced into the gap between the membrane and the counter electrode in a capacitive pressure sensor, resulting in an improved dynamic range.

Various exemplary embodiments relate to a device to measure carbon dioxide (CO.sub.2) levels, including a first oscillator group comprising a first sensor to measure air pressure, where the first sensor comprises a first sealed membrane, and where the first sealed membrane overlays a sealed first cavity; a second oscillator group including a second sensor to measure the resonance frequency of a second unsealed oscillating membrane, and where the second unsealed membrane overlays a second cavity in contact with the air outside of the second sensor; and a mixer accepting as input a first frequency measurement output from the first oscillator group and a second frequency measurement output from the second oscillator group, outputting the difference of the first frequency measurement and the second frequency measurement, and computing a carbon dioxide measurement based on the difference.

A system and method mitigate the effects of these external vibrations on a capacitance diaphragm gauge by sensing the motion of the diaphragm at the first natural frequency of the diaphragm of the CDG. The presence of the natural frequency signals superimposed on the pressure signal is determined by sensing variations in the output of a sensor at or near the known natural frequency of the diaphragm and filtering that known low frequency from the output. The filtered signal is used in a feedback circuit to impose electrostatic forces on the diaphragm. The imposed electrostatic forces oppose the motion created by the external vibration to suppress the effects of the vibration on the pressure measured by the CDG.

An integrated optical transducer for detecting dynamic pressure changes comprises a micro-electro-mechanical system, MEMS, die having a MEMS diaphragm with a first side exposed to the dynamic pressure changes and a second side, and an application-specific integrated circuit, ASIC, die having an optical interferometer assembly. The interferometer assembly comprises a beam splitting element for receiving a source beam from a light source and for splitting the source beam into a probe beam in a first beam path and a reference beam in a second beam path, a beam combining element for combining the probe beam with the reference beam to a superposition beam, and a detector configured to generate an electronic interference signal depending on the superposition beam. The MEMS die is arranged with respect to the ASIC die such that a gap is formed between the second side of the diaphragm and the ASIC die, with the gap defining a cavity and having a gap height. The first beam path of the probe beam comprises coupling into the cavity, reflection off of a deflection point or a deflection surface (16) of the diaphragm and coupling out of the cavity.

A blood pressure detection device manufactured by a semiconductor process includes a substrate, a microelectromechanical element, a gas-pressure-sensing element, a driving-chip element, an encapsulation layer and a valve layer. The substrate includes inlet apertures. The microelectromechanical element and the gas-pressure-sensing element are stacked and integrally formed on the substrate. The encapsulation layer is encapsulated and positioned on the substrate. A flowing-channel space is formed above the microelectromechanical element and the gas-pressure-sensing element. The encapsulation layer includes an outlet aperture in communication with an airbag. The driving-chip element controls the microelectromechanical element, the gas-pressure-sensing element and valve units to transport gas. The gas is introduced into the flowing-channel space through the inlet apertures and transported into the airbag through the outlet aperture, to inflate the airbag for blood pressure measurement, and a detection datum of blood pressure outputted by the gas-pressure-sensing element is transmitted to the microprocessor to calculate.

A quartz pressure sensor that resonates in the thickness-shear mode can include a center resonator structure and first and second caps joined to the center resonator structure by bond joints. Each bond joint is comprised of a sealing glass having thickness less than 0.0012 inches (˜30 μm) and a melting point less than 573° C. The quartz pressure sensor can additionally include an inner diameter edge feature formed between the interior sidewall in the joint sidewall of the caps that reduces stresses at the bond joints and/or a high stress point in the cap bore.