Abstract: A mirror for a piezoelectric resonator consisting of alternately arranged layers of high and low acoustic impedance is manufactured by at first producing a first layer on which a second layer is produced, so that the second layer partially covers the first layer. Then, a planarization layer is applied on the first layer and on the second layer. Subsequently, a portion of the second layer is exposed by structuring the planarization layer, wherein the portion is associated with an active region of the piezoelectric resonator. Finally, the resulting structure is planarized by removing the portions of the planarization layer remaining outside the portion.

Abstract: A method for operating a piezoelectric element is disclosed. A first voltage is applied to a piezoelectric element and produces a first deflection of the piezoelectric element with a travel. An electrical discharge of the piezoelectric element after the application of the first voltage results in a first contraction of the piezoelectric element by a first compression. After the first contraction, a second voltage is applied to the piezoelectric element, whose polarity is opposite that of the first voltage and causes a further contraction of the piezoelectric element by a second compression. Repeated application of the first voltage after the electrical discharge of the applied second voltage results in a deflection of the piezoelectric element with the same travel.

Abstract: Enhanced mechanical designs are provided for weak-link rotary mechanisms for implementing angular rotations with a defined angular travel range and positioning resolution, for example, with ten-degree-level travel range and ten-nanoradian-level positioning resolution. A weak-link rotary structure has a predetermined pattern for implementing angular rotations with repeatable and reliable angular travel range and positioning resolution including a plurality of connecting links radially extending from a central portion with a predefined angular separation between the connecting links; each said connecting link having at least one pair of weak-link connections; alternate connecting links being coupled to a respective terminal, each said respective terminal being mounted to a connecting carriage; remaining other connecting links being coupled to a respective mounting portion of a mating part of the weak-link rotary structure.

Abstract: A driving device includes a motor, a first rotating portion, a second rotating portion, a piezoelectric assembly, and a controlling unit. The motor includes a rotating shaft. The first rotating portion is fixed to the rotating shaft. The second rotating portion is engaged with the first rotating portion. The piezoelectric assembly is sandwiched between the first rotating portion and the second rotating portion. The controlling unit is electrically connected to the motor and the piezoelectric assembly. The controlling unit is configured for storing a predetermined voltage, and determining whether an electric voltage output by the piezoelectric assembly is greater than or equal to the predetermined voltage and inactivating the motor if the electric voltage output by the piezoelectric assembly is greater than or equal to the predetermined voltage. A protection method for the driving device is also provided.

Abstract: A method for manufacturing a ferroelectric member element structure having a ferroelectric member film, and lower and upper electrodes between which the ferroelectric member film is sandwiched, includes the steps of: forming a buffer layer having pattern-shaped oriented growth on a monocrystal substrate; performing oriented growth of the lower electrode layer on the buffer layer; performing oriented growth of the ferroelectric member film to cover the buffer layer and the lower electrode layer; and removing a portion of the ferroelectric member film other than the portion having the oriented growth achieved along the pattern of the buffer layer, by means of an etching treatment.

Abstract: The present invention describes a system for accurately measuring the concentration of a substance within a filter housing. A concentration sensor and a communications device are coupled so as to measure and transmit the concentration of a particular substance within the filter housing while in use. This system allows the operator to certify the integrity of the filters within the filter housing at the customer site without additional equipment. In one embodiment, a tracer gas, such as helium or hydrogen, is added to a carrier and injected into the system. The concentration of tracer gas at a specific operating transmembrane pressure is indicative of bubble pointing specific pores in the filter. This test will give a more sensitive indication of the bubble point and the presence of defects than a standard diffusion test. In a second embodiment, two gasses, in a known ratio, are introduced into the filter housing.

Abstract: A piezoelectric multilayer component includes a stack of piezoceramic layers and electrode layers arranged one above another. At least one piezoceramic layer is printed with a layer structured according to a predefined pattern in a piezoelectrically inactive zone of the stack. The structured layer has at least one connecting element by which piezoceramic layers that are adjacent in the stacking direction are mechanically connected to one another with a first strength. The structured layer has interspaces filled at least in part with piezoceramic material of the adjacent piezoceramic layers. The adjacent piezoceramic layers in the interspaces are mechanically connected to one another with a second strength, which is less than the first strength.

Abstract: Patterns detection to input data containing a plurality of transactions, each transaction having at least one item, is carried out in the following way. Filter conditions for interesting patterns are received, and a first wet of filter conditions applicable in connection with generation of candidate patterns is determined.

Abstract: A foreign substance removing apparatus that can provide the desired vibration amplitude to a light transmitting member, without using a large driving voltage. The foreign substance removing apparatus removes foreign substances adhered to a surface of an optical member disposed in a light ray incident path and includes a piezoelectric element fixed to a first plane of the optical member, a circular disk fixed to a second plane, opposite from the first plane, of the optical member so as to face the piezoelectric element, and a driving unit for applying an AC voltage to the piezoelectric element to cause the optical member to elastically vibrate in a direction perpendicular to the planes thereof, thereby removing the foreign substances adhered to the surface of the optical member.

Abstract: Systems and methods for lithography include actuating an electroactive polymer member to position mask and/or substrate.

Abstract: A piezoelectric measuring element comprises at least one bar with transverse effect which can be used with two conductor technology. Poles comprising the metallizations, electrodes and lines in the measuring element are embodied with one or more piezoelectric bars with transverse effect such that the electric capacitances thereof with respect to the housing are identical. There can be a completely symmetrical design of the poles. A capacitor from one pole to the housing can correspond to the difference in capacitance of both poles to the environment.

Abstract: The present invention relates to an electromechanical transducer, in particular an electromechanical sensor, actuator and/or generator, which exhibits a polymer element that is obtainable from a reaction mixture comprising a polyisocyanate or a polyisocyanate prepolymer or a mixture thereof and a compound with at least two isocyanate-reactive amino groups. Moreover, the present invention relates to a process for producing an electromechanical transducer of such a type and also to the use of a polymer element of such a type as an electromechanical element. Furthermore, the present invention relates to an electronic and/or electrical apparatus that includes an electromechanical transducer according to the invention, and also to the use of an electromechanical transducer according to the invention in an electronic and/or electrical apparatus.

Abstract: An electro-mechanical transducer is disclosed, which provides a wideband response by activating successive multiple resonant frequencies in a way which provides additive output between the resonant frequencies with reduced cancellation below the first resonance and means for controlling the response by reducing the voltage drive. A multiply resonant wideband high output transducer is disclosed.

Abstract: A multiple degrees of freedom motion system comprising an arrangement of rigid stages, flexure constraint modules, actuators, and sensors. These components of the motion system are arranged and connected in a systematic fashion to provide a high degree of decoupling between the motion axes, suitable placement of ground-mounted actuators to actuate each motion axis, and suitable placement of sensors to allow end-point measurement along each motion axis. This arrangement of rigid stages, flexure constraint modules, actuators and sensors enables large motion range and high motion quality in the motion system, while using standard and commonly available components.

Abstract: An artificial neuromuscular unit (ANMU) network comprising: a plurality of ANMUs, wherein each ANMU comprises an electroactive polymer (EAP) actuator layer and a uniquely addressable EAP logic layer coupled to the actuator layer; a plurality of inert, non-ion-conducting and non-charge-conducting interfaces mechanically coupled between the ANMUs such that the actuator layer of each ANMU is insulated from the actuator layers and logic layers of the other ANMUs; an EAP common conductor layer coupled to the logic layer of each ANMU such that the logic layer of each ANMU is interposed between the common conductor layer and the corresponding actuator layer; and wherein the logic layer of each ANMU is configured to control the transfer of energy to and from the common conductor layer and the corresponding actuator layer.

Abstract: The disclosure pertains to a device and a method for compensating for heat expansion effects in solid materials, as well as a method for manufacturing the device.

Abstract: An apparatus for producing a holding or transmission frame (12, 20) for an electrostrictive actuator, in particular, a stacked piezoactuator (5) includes the following steps: a) a winding spindle (52), corresponding to the shape of the inner periphery of the frame (12, 20), is wound with several layers of a unidirectional prepreg for forming a laminate body; b) the laminate body is hardened; c) the hardened laminate body in the frame is cut by sections parallel to the direction of winding. An electrostrictive drive (100) includes an electrostrictive actuator (5) in which the length varies during actuation, and a transmission frame (12) that surrounds the actuator, is connected to the actuator for initiating the variation in length of the actuator and for amplifying the actuator, the transmission frame (12) being made of a prepreg that is wound in the laminate body and hardened.

Abstract: An optical apparatus includes a vibrated member and a piezoelectric element. The piezoelectric element vibrates the vibrated member at a predetermined vibration mode to remove a foreign substance adhered to a surface of the vibrated member. A drive electrode, a first vibration detection electrode and a second vibration detection electrode are provided on a first face of the piezoelectric element, and a ground electrode is provided on a second face of the piezoelectric element. The first vibration detection electrode and the second vibration detection electrode have an axis-symmetrical shape, and are arranged on the first face of piezoelectric element so as to be symmetrical with respect to an axis along which a predetermined vibration node occurs when the vibrated member vibrates at the predetermined vibration mode.

Abstract: Apparatus (5,50) for generating torsional-mode ultrasonic vibrations comprises a stack of axially-polarised piezo-electric ceramic rings (10) having a torsional converter (1,51,53) mounted coaxially to either one face of the stack or to two opposite faces thereof. Each torsional converter (1,51,53) has a cross-sectional inhomogeneity comprising a plurality of helically-extending grooves (2,55) extending substantially from end to end of the converter. The grooves (2,55) each have a length, measured axially along the converter (1,51,53), of approximately half the wavelength of ultrasonic vibrations therein. When the stack is energised, the stack and the converter (1) or converters (51,53) resonate together in a purely torsional-mode vibration. The apparatus (5,50) is compact and axisymmetric, and is straightforward to incorporate into a simple tool handpiece. The ultrasonic vibrations may be transmitted along a conventional elongate waveguide (3) of a tool to a distal operative tip (35).

Abstract: A piezoelectric generator that includes a piezoelectric element having first and second surfaces on which a first electrode and a second electrode are disposed. A vibrating plate is bonded to the piezoelectric element such that the first surface is adjacent thereto. The vibrating plate includes a first bend disposed at a first side of a vibrating-plate main section to which the piezoelectric element is bonded and a second bend disposed at a second side thereof. A support member supports the vibrating plate at a location outside the first and second bends. A vibration body including the vibrating-plate main section and the piezoelectric element is supported at both ends.

Abstract: A movable table unit provided here has a simple structure but can increase the precision of detecting the displacement of a movable table, and comprises a quadrangle frame-shaped stationary base a movable table disposed inside the stationary base, spring members interposed between the movable table and the stationary base, and a piezoelectric element fixed to either the stationary base or the movable table and capable of expanding/contracting in the axis direction to exert either an expansion or contraction force on the other, to allow the movable table to move relative to the stationary base. A strain gauge is mounted in a strain occurrence site where strain occurs as the movable table moves, so that the amount of travel of the movable table is detected on the basis of the value detected by the strain gauge.

Abstract: A casing for encapsulation of an electrical component, for example a piezoelectric actuator, comprising an outer layer of a semipermeable material and an inner layer comprising a chemically active, hydrophilic substance that chemically combines with water to form a compound.

Abstract: A piezoelectric speaker includes a cabinet, piezoelectric vibrators horizontally mounted inside the cabinet at different elevations each having two eyed lugs respectively coupled to respective posts in the cabinet, a shock absorber coupled to the piezoelectric material of the piezoelectric vibrators, two conducting terminals accommodated inside the cabinet and clamped on the piezoelectric vibrators, and two clamps fastened to the conducting terminals to secure a respective signal line.

Abstract: Microelectromechanical systems with structures having piezoelectric actuators are described. The structures each have a body that supports piezoelectric islands. The piezoelectric islands have a first surface and a second opposite surface. The piezoelectric islands can be formed, in part, by forming cuts into a thick layer of piezoelectric material, attaching the cut piezoelectric layer to a body having etched features and grinding the piezoelectric layer to a thickness that is less than the depths of the cuts. Conductive material can be formed on the piezoelectric layer to form electrodes.

Abstract: An electronic device 10 includes a layered piezoelectric element 20 and a driven member 30. The driven member 30 is bonded to the top surface 20a of the layered piezoelectric element 20 by means of an epoxy resin adhesive S. The piezoelectric element 20 includes a side electrode 24 on one side surface of the element, which is one of the outer surfaces of the element 20. The piezoelectric element 20 includes, in the vicinity of the upper end portion of the side surface, a dam portion 28 formed of a material for preventing epoxy bleed out of the adhesive S. Therefore, even when the epoxy bleed out of the adhesive S occurs, a bled-out portion of the components of the adhesive S does not reach the side electrode 24. Thus, when the side electrode is connected to an external circuit by, for example, soldering, reduction in the connection strength or similar problems can be avoided.

Abstract: Embodiments of a missile, an airframe and a structure comprising piezoelectric fibers and a method for active structural response control are generally described herein. In some embodiments, a housing structure includes a composite material containing a plurality of piezoelectric fibers adapted to generate an electrical signal in response to a deformation in the structure and to deform the structure to provide low frequency stiffness and strength performance while attenuating high frequency vibrations.

Abstract: There are some cases where cracks occur at a plurality of areas on an external electrode when a displacement quantity of a laminated piezoelectric element is large. In such cases, there is a possibility of a voltage not being applied to a portion of the laminated structure due to the cracks caused by a long time drive to cause a reduction in the displacement quantity. A low rigidity layer is arranged on the laminated structure to form a plurality of portions divided by the low rigidity layer in a laminating direction. Each portion is provided with power feeding members on the anode side and the cathode side. Thus, a voltage can be stably supplied to each internal electrode.

Abstract: A micro-electromechanical systems (MEMS) ultrasonic transducer device includes a substrate defining an opening and an active transducer having multiple of active layers stacked over the opening of the substrate. The active transducer is completely encapsulated by multiple passivation layers.

Abstract: Striped sheets each having a structure in which two types of first layers and second layers are stacked in the X direction are prepared. More specifically, first raw material sheets having the same composition as the first layers and second raw material sheets having the same composition as the second layers are regularly alternately stacked in the X direction to prepare a uniaxial stack. The uniaxial stack is then cut along the X direction to prepare the striped sheets. A large number of striped sheets and a large number of homogeneous sheets are then collected to form a sheet group. The striped sheets and the homogeneous sheets are alternately stacked in the Y direction different from the X direction to prepare a biaxial stack having two stacking axes in the X direction and the Y direction. The biaxial stack is fired to produce a ceramic structure.

Abstract: A compact auto focus lens module includes a piezoelectric actuator, an elastic element, at least two guiding fixtures, and a lens barrel with an optical lens set therein. By elastic force of the elastic element, a friction is generated between the lens barrel and the piezoelectric actuator. While being applied with a voltage, the lens barrel driven by the movement of the piezoelectric actuator moves along the optical axis under the guidance of the guiding fixtures. Due to fewer elements, compact volume, and light weight, the design is applied to a miniature auto focus lens modules so as to achieve effects of fast movement, stable focusing and reduced tilting.

Abstract: An injection system for injecting fuel has: a housing for containing the fuel, with a first and second aperture, a piezo actuator having a first and second face plate aperture, a controllable piezo stack arranged between the face and base plate, a sealed casing laterally surrounding at least the piezo stack and arranged between the face and base plate and a transmission means arranged in an actuator interior space having a fluid, a first contact device guided through the first aperture and face plate aperture, a second contact device guided through the second aperture and face plate aperture, a first sealing device surrounding the contact device near the apertures and providing a seal between the housing interior and exterior space and a second sealing device surrounding the contact devices near the face plate apertures and providing a seal between the housing interior space and the actuator interior space.

Abstract: The present invention relates to a micro-electro-mechanical systems (MEMS) vibrating structure supported by a MEMS anchor system, and includes a single-crystal piezoelectric thin-film layer having domain inversions, which determine certain vibrational characteristics of the MEMS vibrating structure. The MEMS vibrating structure may have dominant lateral vibrations or dominant thickness vibrations. The single-crystal piezoelectric thin-film layer may include Lithium Tantalate or Lithium Niobate, and may provide MEMS vibrating structures with precise sizes and shapes, which may provide high accuracy and enable fabrication of multiple resonators having different resonant frequencies on a single substrate.

Abstract: A piezoelectric vibrator is used in an electronic device having a screen. The piezoelectric vibrator includes a diaphragm, at least one piezoelectric layer attached to the diaphragm, and a vibrating element extending from the diaphragm for being coupled to a surface of the screen.

Abstract: A piezoelectric multilayer component includes a stack of piezoceramic layers, which are arranged one on top of the other, and electrode layers. The stack has a first area and a second area. The second area contains a disturbance material, which is used to make the second area less mechanically robust than the first area.

Abstract: A method for generating power in a wellbore includes moving an actuator; inducing an oscillating stress on a piezoelectric component with the actuator; and generating a voltage with the piezoelectric component in response to the induced stress on the piezoelectric component.

Abstract: A piezoelectric multi-layer component is described herein. The component includes a plurality of ceramic layers, and one or more electrode layer. The one or more electrode layer has a material structure that is different than the plurality of ceramic layers and is configured to at least partially block a propagation in a longitudinal direction of pressure waves acting on the piezoelectric multi-layer component.

Abstract: The invention provides a (Li, Na, K)(Nb, Ta)O3 type piezoelectric/electrostrictive ceramic composition capable of being sintered at a low temperature and providing good electric field-induced strain at the time of high electric field application at a temperature for practical use. The piezoelectric/electrostrictive ceramic composition has an ABO3 type composition formula wherein lithium, sodium, and potassium are contained as first elements; niobium and tantalum are contained as second elements; oxygen (O) is contained as a third element; A/B ratio is higher than 1; and the ratio of the number of Ta atoms to the total number of atoms of the second elements is 10 mol % or more and 50 mol % or less, and comprises a perovskite type oxide wherein the first elements are A site composing elements and the second elements are B site composing elements.

Abstract: A driving apparatus (100) is provided with: a base portion (110); a stage portion (130) on which a driven object (12) is mounted and which can be displaced; an elastic portion (120) which connects the base portion and the stage portion and which has elasticity to displace the stage portion in one direction; a first applying device (141, 142, 143, 22) for applying an excitation force for displacing the stage portion such that the stage portion is resonated in the one direction (Y axis) at a resonance frequency determined by the stage portion and the elastic portion; and a second applying device (161, 162, 22) for applying a driving force for displacing, in a stepwise manner or in a continuous manner, the stage portion or the driven object mounted on the stage in other direction (X axis).

Abstract: An actuator includes: a substrate; a fixed electrode provided on a major surface of the substrate; a first dielectric film provided on the fixed electrode, and made of crystalline material; a movable beam opposed to the major surface, and held above the substrate with a gap thereto; a movable electrode; and a second dielectric film. The movable electrode is provided on a surface of the movable beam facing the fixed electrode, and has an alternate voltage applied between the fixed electrode and the movable electrode. The second dielectric film is provided on a surface of the movable beam facing the fixed electrode, and is made of crystalline material.

Abstract: A piezoelectric-driven diaphragm pump is comprised of a driving unit (1) having a driving diaphragm (12) and a first housing (11), a replaceable driven unit (2) having a driven film (241) and a second housing (21), and a fixing unit (3) for fixing the driven unit (2) to the driving unit (1). A vibration transmitting face (14) of the driving diaphragm (12) from which displacement of the driving diaphragm (12) is transmitted to the driven film (241) and a vibration transmitted face (241a) of the driven film (241) to which the displacement of the driving diaphragm is transmitted are not parallel to a reference plane (11b) of the first housing (11) which faces the second housing (21), and the vibration transmitting face (14b) of the driving diaphragm (12) contacts with entire of the vibration transmitted face (241a) of the driven film (241). Thereby, the displacement of the driving diaphragm (12) is efficiently transmitted to the driven film (241), so that a capacity of a pump room (25) can be varied largely.

Abstract: A linear drive ultrasonic motor includes at least an ultrasonic vibrator having a piezoelectric element, a driven member which is driven by a frictional force between the driven member and the ultrasonic vibrator, a pressing member which presses the ultrasonic vibrator such that a frictional force is generated between the ultrasonic vibrator and the driven member, a guiding mechanism which movably supports the driven member, and a case member which accommodates the ultrasonic vibrator, the pressing member, and the guiding means. The case member includes a first opening portion for making the driven member pass through, and a second opening portion which opens in a direction different from a direction in which the first opening portion opens and a direction of pressing by the pressing member.

Abstract: The present invention relates to a piezoelectric linear motor that can make relatively low abrasion and accurate linear movement since stationary AC voltages are applied to two piezoelectric elements with a phase difference. The present invention provides a piezoelectric linear motor, comprising: a piezoelectric substrate having a first piezoelectric element and a second piezoelectric element, wherein AC voltages are applied to the first and second piezoelectric elements with a phase difference; a metallic elastic body having first and second elastic bodies coupled to the piezoelectric elements and a central protrusion protruded at the central portion connecting the first and second elastic bodies, wherein the central protrusion oscillates elliptically during an application of the voltage; and a mover brought into contact with the central protrusion of the metallic elastic body for a linear movement, and wherein the movement of the mover is orthogonal to the central protrusion.

Abstract: A motor which includes two drive elements, especially piezoelectric bending actuators, having effective directions that are perpendicular to each other. These actuators act upon a drive ring to thereby rotate a shaft. Two tension-compression bars, which are parallel to an effective direction, are connected to the drive ring, have respective joints at their ends and are connected to the ends of a diagonal bar, relative to which the ring can be displaced in the other effective direction. The diagonal bar itself can be displaced relative to fixing elements to an effective direction via a diagonal suspension. The drive is compact, having actuators that are non-radially hinged to the ring.

Abstract: The invention relates to a fine positioning system using an inertial motor based on a mechanical amplifier that comprises a first amplified inertial sub-assembly including a mechanical amplifier, a piezoactive member and a countermass. A second relative drive sub-assembly includes a clamp and a clamped member attached to the first amplified inertial sub-assembly. Asymmetric excitation cycles of the first inertial sub-assembly generate impact forces and movements amplified in a driving direction (z), thus resulting in sliding and adhesion successions of the clamped member in the clamp in order to generate a relative translation movements of the points A and B relative to the point D. The mechanical amplifier increases the step size and reduces the supply inrush currents. Fine and dynamic positioning of the point B relative to the point D can be achieved with augmented strokes using the amplifier.

Abstract: The invention relates to a piezoelectric actuation structure including at least one strain gauge and at least one actuator produced from a stack on the surface of a substrate of at least one layer of piezoelectric material arranged between a bottom electrode layer and a top electrode layer, at least a portion of the stack forming the actuator being arranged above a cavity produced in the substrate, characterized in that the strain gauge is a piezoresistive gauge located in the top electrode layer and/or the bottom electrode layer, the layer or layers including electrode discontinuities making it possible to produce said piezoresistive gauge. The invention also relates to a method for producing such a structure.

Abstract: A multi-layer piezoelectric element of high durability wherein the internal electrodes and the external electrodes do not break even when operated continuously over a long period of time under high electric field and high pressure is provided. The first multi-layer piezoelectric element according to the present invention comprises a stack formed by stacking piezoelectric layers and internal electrodes alternately one on another and external electrodes formed on a first side face and on a second side face of the stack, wherein one of the adjacent internal electrodes is connected to the external electrode formed on the first side face and the other internal electrode is connected to the external electrode formed on the second side face, and the external electrodes include an electrically conductive material and glass and is formed from a porous electrically conductive material that has a three-dimensional mesh structure.

Abstract: The present invention provides an actuator exhibiting improved performance. The actuator is formed of an electrically conductive thin film formed from an ionic liquid and carbon nanotubes having an aspect ratio of not less than 104; or an electrically conductive thin film formed from an ionic liquid and carbon nanotubes having a length of not less than 50 ?m.

Abstract: A thermoacoustic array energy converter consists of heat driven thermoacoustic prime movers in parallel coupled by means of an acoustic cavity to a piezoelectric electrical generator whose output is rectified and fed to an energy storage element. The prime movers convert heat to sound in a resonator. The sound form a phase-locked array is converted to electricity by means of the piezoelectric element. The generated electric energy is converted to DC by means of a rectifier set and it is then stored in a battery or supercapacitor. The generated electric energy can also be converted to power line frequency.

Abstract: An actuation system for at least two mobile elements with dynamically compensated and opposite relative motions, without disturbance of the elements fixed in the same rigid structure as it, and resistant to exterior loadings, in the case of a translational motion of the mobile elements, includes, in a rigid structure, at least one linear actuator linked to a motion transmission device with four rigid arms, articulated at their ends and forming a lozenge, of which each of two first opposite vertices is linked to a corresponding mobile element, and whose other two opposite vertices have a single translational degree of freedom.

Abstract: The invention relates to micro-fabricated devices having a suspended membrane or plate structure and micro-fabrication techniques for making such devices. A substrate defines a cavity passing through the substrate, and the cavity defines a first opening. An intermediate portion is disposed over the substrate and defines a second opening. The second opening is larger in size than the first opening, and the dimensions of the second opening are controlled according to a parameter associated with performance of the device. A membrane is positioned adjacent the second opening.