Abstract: A wafer with through wafer interconnects. The wafer includes spaced through wafer vias which extend between the back side and front side of the wafer. A conductor within each of said vias connects to front and back side pads. Functions associated with said conductor and said pads provide a depletion region in the wafer between the pads and wafer or pads and conductor and the wafer.

Abstract: There is described a micromachined ultrasonic transducers (MUTS) and a method of fabrication. The membranes of the transducers are fusion bonded to cavities to form cells. The membranes are formed on a wafer of sacrificial material. This permits handling for fusions bonding. The sacrificial material is then removed to leave the membrane. Membranes of silicon, silicon nitride, etc. can be formed on the sacrificial material. Also described are cMUTs, pMUTs and mMUTs.

Abstract: A microfabricated acoustic transducer with suppressed substrate modes includes a diaphragm containing an upper electrode suspended above a substrate containing a lower electrode; the substrate may or may not contain electronic circuits. The substrate modes are suppressed by either thinning the substrate such that a longitudinal ringing mode occurs outside of the frequency band of interest or applying a judiciously designed damping material that absorbs acoustic energy from the substrate on the backside of the transducer substrate, or by both thinning the substrate and applying the damping material. The damping material has an acoustic impedance that matches the acoustic impedance of the substrate and is lossy.

Abstract: The present invention relates to an electret condenser microphone including the vibratory diaphragm which is comprised of an electret film into which an electric charge is charged; a conductive film formed on one side of the electret film and a polar ring disposed at a peripheral edge of the underside of the conductive film. Also, this microphone includes a vibratory diaphragm support member which is disposed on the vibratory diaphragm and has a concave groove and a concave portion. On the vibratory diaphragm support member is attached an integrated circuit serving to receive and amplify a transformed electrical signal from the vibratory diaphragm.

Abstract: A capacitor microphone includes a case having an end wall defining an opening for a sound hole, a capacitor portion comprising a diaphragm, a back plate and a spacer, the diaphragm opposing to the back plate via the spacer, the capacitor portion being accommodated in the case in such an manner as the diaphragm is placed on the side of the end wall, and a substrate accommodated in the case farther from the end wall than the capacitor portion, the substrate having an impedance conversion element mounted on a surface thereof facing the capacitor portion. A communicating opening is provided around the back plate in a position opposing to the impedance conversion element for communicating spaces on the front and back sides of the back plate. The communicating opening has a larger area than that of the top of the impedance conversion element to allow the spaces on both sides of the back plate to communicate with each other.

Abstract: A micro-machined ultrasonic transducer (MUT) substrate that reduces or eliminates the lateral propagation of acoustic energy includes holes, commonly referred to as vias, formed in the substrate and proximate to a MUT element. The vias in the MUT substrate reduce or eliminate the propagation of acoustic energy traveling laterally in the MUT substrate. The vias can be doped to provide an electrical connection between the MUT element and circuitry present on the surface of an integrated circuit substrate over which the MUT substrate is attached.

Abstract: A capacitive ultrasound transducer including a dielectric diaphragm with an electrode; a porous layer; and a spacer structure between the diaphragm and porous layer for defining a capacitive gap between them; the pores of the porous layer providing a compliant reservoir for the fluid in the gap.

Abstract: An ultrasonic transducer is formed by a plurality of cMUT cells, each comprising a charged diaphragm plate capacitively opposing an oppositely charged base plate. The cMUT cells can be fabricated by conventional semiconductor processes and hence integrated with ancillary transducer circuitry such as a bias charge regulator. The cMUT cells can also be fabricated by micro-stereolithography whereby the cells can be formed using a variety of polymers and other materials.

Abstract: An acoustic transducer is disclosed including: a fixed perforated member; a freely movable diaphragm spaced from the perforated member; a support ring in the perforated member maintaining the proper spacing between the diaphragm and the perforated member near the perimeter; means of suspension allowing the diaphragm to rest freely on the support ring and yet mechanically decouples the diaphragm from the perforated member; means of applying an electrical field in the space between the perforated member and the diaphragm; means of detecting the change of electrical capacitance between the perforated member and the diaphragm when the diaphragm moves in response to an incident acoustic sound pressure wave.

Abstract: A method and system for controlling bias voltage for use with an electrostatic transducer are provided. The bias voltage is dynamically varied or set as a function of imaging mode, depth gain compensation, elevational apodization, azimuthal apodization, timing with respect to the transmit waveform, center frequency of transmit and receive waves and desired modulation. Opposite polarity on sub-elements is also provided for removing signals from electromagnetic interference and crosstalk between elements.

Abstract: The present invention relates solid state silicon-based condenser microphone systems suitable for batch production. The combination of the different elements forming the microphone system is more flexible compared to any other system disclosed in the prior art. Electrical connections between the different elements of the microphone system are established economically and reliably via a silicon carrier using flip-chip technology. The invention uses an integrated electronic circuit chip, preferably an application specific integrated circuit (ASIC) which may be designed and manufactured separately and independent of the design and manufacture of the transducer element of the microphone. The complete sensor system can be electrically connected to an external substrate by surface mount technology with the contacts facing one side of the system that is not in conflict with the above-mentioned interface to the environment.

Abstract: The damping of membranes of ultrasound transducers in an arrangement occurs at the front side directly on the membranes by applying a polymer layer, whereby the working temperature dependent on the operating frequency of the ultrasound transducer lies within the glass transition range of the polymer layer.

Abstract: A wide frequency band micromachined microphone including a plurality of micromachined cells of the type including electrodes carried by a membrane supported above a common electrode with conductive lines interconnecting the electrodes is described. A method of operating a microphone array is also described.

Abstract: A vibration wave detector having a first diaphragm for receiving vibration waves, such as sound waves and so on, to be propagated in a medium, a resonant unit having a plurality of cantilever resonators each having such a length as to resonate at an individual predetermined frequency, a retaining rod for retaining the resonant unit, a second diaphragm positioned on the opposite side of the first diaphragm with respect to the retaining rod, and a vibration intensity detector for detecting the vibration intensity, for each predetermined frequency, of each of the resonators, by the vibration waves received by the first diaphragm and propagated to the resonant unit through the retaining rod.

Abstract: There is described a cMUT array with transducer elements which include a plurality of cells with membranes formed on one surface of a wafer. Voltages applied between said spaced electrodes drive said membranes. The voltages applied to said electrodes are applied from the opposite surface of the wafer through the wafer and through vias formed in the wafer.

Abstract: An acoustic transducer is disclosed including: a fixed perforated member; a freely movable diaphragm spaced from the perforated member; a support ring in the perforated member maintaining the proper spacing between the diaphragm and the perforated member near the perimeter; means of suspension allowing the diaphragm to rest freely on the support ring and yet mechanically decouples the diaphragm from the perforated member; means of applying an electrical field in the space between the perforated member and the diaphragm; means of detecting the change of electrical capacitance between the perforated member and the diaphragm when the diaphragm moves in response to an incident acoustic sound pressure wave.

Abstract: A wide frequency band micromachined microphone including a plurality of micromachined cells of the type including electrodes carried by a membrane supported above a common electrode with conductive lines interconnecting the electrodes is described. A method of operating a microphone array is also described.

Abstract: There is described a capacitive micromachined ultrasonic transducer array which is configured to minimize the excitation and propagation of plate waves traveling in the substrate and ultrasonic waves propagating at the interface between the array surface and the immersion fluid.

Abstract: An electrostatic transducer having respective first and second stators, each having an interior surface, which are displaced and juxtaposed, and including a flexible diaphragm leaving a conductive layer and being operable as an electrostatic emitter. The diaphragm includes an emitter portion which is interposed between the respective interior surfaces of the first and second stators and is configured as a nonplanar film characterized by a continuous array of peaks and valleys. The emitter portion of the diaphragm is positioned adjacent, but substantially unattached to the respective interior surfaces of the first and second stators. The peaks of the emitter portion of the diaphragm may contact the interior surfaces, or may be displaced therefrom. Also disclosed is a method for generating audio output from an electrostatic transducer utilizing a nonplanar emitter portion of a flexible, film diaphragm.

Abstract: The invention relates to a method for attaching a micromechanical microphone (1) to be used in connection with a mobile station to a substrate (2), in which a diaphragm (4) and back electrode (6) for the microphone (1) are placed within a distance of each other, wherein an air gap (7) is formed between the diaphragm (4) and the back electrode (6). An insulation ring (12) is placed between the microphone (1) and the substrate, wherein the back electrode (6), the substrate (2) and the insulation ring (12) define a back chamber (13). The microphone (1) is attached to the substrate (2) with fixing means (11a, 11b), wherein the volume (Vb) of the back chamber (13) is adjusted by adjusting the height of the fixing means (11a, 11b).

Abstract: The invention relates to a capacitor microphone having a housing, a first membrane, a backplate electrode associated with this membrane, and an opening through which sound can reach the membrane. It is therefore the task of the invention to provide an effective protection against sweat penetration into the microphone, thus overcoming prior art disadvantages and problems.

Abstract: A solid state silicon-based condenser microphone comprising a silicon transducer chip (1). The transducer chip includes a backplate (13) and a diaphragm (12) arranged substantially parallel to each other with a small air gap in between, thereby forming an electrical capacitor. The diaphragm (12) is movable relative to the backplate (13) in response to incident sound. An integrated electronic circuit chip (3) or ASIC is electrically coupled to the transducer chip (1). An intermediate layer (2) fixes the transducer chip (1) to the integrated electronic circuit chip (3) with the transducer chip (1) on a first side of the intermediate layer (2) and the integrated electronic circuit chip (3) on a second side of the intermediate layer (2) opposite the first side. The intermediate layer (2) has a sound inlet (4) on the same side as the ASIC giving access of sound to the diaphragm.

Abstract: An arrangement for determining the distance of objects has a number of electrostatic ultrasonic transducers which are formed from superposed layers. Fixed electrodes for the transducers and conductive tracks connected to them are formed in a first structured metal layer. The other layers are an insulation layer and a full-surface second metal layer on the insulation layer which provides counterelectrodes for the electrodes provided by the first metal layer.

Abstract: Electrostatic transducers (10, 100) for generating and/or sensing percussion waves have an internal rigid unitary element comprising an insulating sleeve (17, 117), an electrode backplate (21, 121) situated within the sleeve (17, 117), and a dielectric layer (22, 122) which secures the electrode backplate (21, 121) within the sleeve (17, 117). The dielectric layer (22, 122) is a generally continuous layer and has support fingers (24, 124) protruding outwardly away from the electrode backplate (21, 121) for supporting an electrode diaphragm (26, 126), preferably a durable metal foil. The electrode diaphragm (26, 126) may be hermetically sealed to a housing (111), which encloses the unitary element so that the transducers (10, 100) are better suited for harsh, extreme high/low temperature, and/or extreme high/low pressure environments. Furthermore, the interior region (32, 132) of the transducer (10, 100) can be evacuated via a throughway (31, 131) so that the transducer power can be increased.

Abstract: An electrostatic ultrasonic transducer formed on a semiconductor substrate by micro-machining wherein the transducer includes a silicon nitride membrane supported above the surface of the substrate by insulating supports; and the substrate and membrane define the electrodes of the transducer.

Abstract: Electrostatic transducers (10, 100) for generating and/or sensing percussion waves have an internal rigid unitary element comprising an insulating sleeve (17, 117), an electrode backplate (21, 121) situated within the sleeve (17, 117), and a dielectric layer (22, 122) which secures the electrode backplate (21, 121) within the sleeve (17, 117). The dielectric layer (22, 122) is a generally continuous layer and has support fingers (24, 124) protruding outwardly away from the electrode backplate (21, 121) for supporting an electrode diaphragm (26, 126), preferably a durable metal foil. The electrode diaphragm (26, 126) may be hermetically sealed to a housing (111), which encloses the unitary element so that the transducers (10, 100) are better suited for harsh, extreme high/low temperature, and/or extreme high/low pressure environments. Furthermore, the interior region (32, 132) of the transducer (10, 100) can be evacuated via a throughway (31, 131) so that the transducer power can be increased.

Abstract: An acoustic transducer includes a perforated member; a movable diaphragm spaced from the perforated member; spring means interconnecting the diaphragm and the perforated member for movably supporting the diaphragm relative to the perforated member; a pressure equalization slot for controlling the flow of fluid through the diaphragm, the slot equalizing the pressure on opposite sides of the diaphragm for defining the low frequency response; and means for applying an electric field across the perforated member and the diaphragm for producing an output signal representative of the variation in capacitance induced by the variation of the space between the perforated member and the diaphragm in response to an incident acoustic signal.

Abstract: A capacitance-type ultrasonic transducer is disclosed in which a thin insulating plastic film or membrane is coated on one side with a thin film conductor, such as gold, and the back or counter electrode is comprised of a gas permeable conductor material such as sintered bronze. Springs are utilized to apply pressure to maintain good electrical contact between the gold film side of the membrane and an annular conductor. Signals are applied to and taken off of the gas permeable conductor backplate. Due to the porous structure of the back electrode and the gas permeability thereof, variations in ambient presure on the membrane or film are equalized. Ranges of operating freqeuncy can be established by size of particles used to form the sintered electrode.

Abstract: An integrated liquid crystal acoustic transducer includes a substrate chip having a through hole; a movable plate electrode; means for resiliently mounting the movable plate electrode across the hole in the substrate chip; a perforated electrode spaced from the movable plate electrode and mounted across the hole in the substrate chip; and a liquid crystal medium, disposed between the electrodes, whose polarization vector orientation changes in response to electrical and acoustic input to reciprocally convert between electric and acoustic energy.

Abstract: An integrated resonant cavity acoustic transducer includes a substrate chip having a cavity; a movable plate electrode; means for resiliently mounting the movable plate electrode across the cavity in the substrate chip; and a perforated electrode spaced from the movable plate electrode and mounted across the cavity in the substrate chip; the cavity has a depth from the movable electrode to the back wall of the cavity of approximately one quarter wavelength of the acoustic energy for enabling constructive interference between the primary and reflected acoustic wave for maximizing the displacement of said movable electrode.

Abstract: A capacitive electro-mechanical transducer for responding to both push and pull, for example in a road vehicle drawbar, involves axially spaced flanges (3) on the one force-transmitting member lying on opposite sides of a transverse portion (1) of the other member. The force is transmitted resiliently between the flanges and the portion, and there are capacitor plates (11) between the flanges (3) and the portion (1), so that on relative displacement the capacitance of one set of plates increases and that of the other set decreases. The plates are symmetrically disposed, e.g. of annular form, and they, or the dielectric (13) between them, can be wavy.

Abstract: An electroacoustic transducer of the electret type, comprising a case (101) having an opening (102) via which the interior of the case communicates with the surroundings; a backplate (105) and a diaphragm (107) arranged opposite the backplate in the case, the surface of the backplate being provided at least partly with an electret material (106) and at least a part of the surface of the diaphragm being provided with an electrically conductive layer (110); and an annular element (109) for securing the circumference of the diaphragm to the inside wall of the case. According to the invention, the parasitic capacity between the backplate (105) and the annular element (109) is eliminated in that the backplate and the annular element are both electrically connected with the case and thereby have the same potential as the case. This also provides production-technical advantages.

Abstract: An condenser microphone element including a silicon core, a layer of silicon dioxide thereon, and a layer of tantalum pentoxide thereon.

Abstract: A capacitive transducer including a back plate and a tensioned dielectric diaphragm with a conductive layer is operated as a sonic energy emitter and receiver. The polarity of the dc bias applied to the transducer is periodically reversed to prevent charging and polarization of the dielectric diaphragm due to the applied electrostatic field. The bias voltage polarity is controlled in timed sequence with the application of a fluctuating voltage to generate sonic energy with optimum efficiency. Electrical signals resulting from received sonic energy are selectively inverted and provided with compensation for differences resulting from differences in bias polarities.

Abstract: An acoustic transducer includes a perforated capacitor plate; a movable capacitor plate spaced from the perforated plate; springs for movably supporting the movable capacitor plate relative to the perforated plate; and a support structure for supporting the perforated and movable plates, where the movable plate is interconnected to the support structure by the springs and where the plates, springs and support structure form a unified, monolithic structure. The movable plate, springs and support structure are made from a silicon wafer. The transducer also includes a dielectric fluid in the space between the plates; and equipment for applying an electric field across the plates for producing an output signal representative of the variation in capacitance induced by the variation in space between the plates in response to an acoustic signal.

Abstract: A seismometer system which provides readouts of the time integral (Cumulative Absolute Velocity or CAV) of the acceleration time history of an earthquake. CAV is found to be a measure of the structural damage potential of an earthquake. Three triaxial low frequency acceleration sensors are connected into a digital computer system. Each sensor has a capacitive pickoff, whose capacitances determines the length of an electrical pulse; the pulse gates high-frequency clock cycles into a counter. The counts are summed to give the time integral. A microprocessor provides for periodic re-zeroing and other calibration functions, and for the actuation of alarms, relays and electrical pulses for utility shutoff and the like at predetermined levels of CAV. The acceleration time history of the earthquake is stored in the memory for later retrieval if desired. The whole system is contained in a small inexpensive package.

Abstract: A diaphragm tensioning arrangement for a Sell-type ultrasonic transducer assembly is disclosed. The transducer includes a fixed backplate having a substantially planar electrically conductive front surface and a diaphragm having a front surface and back surface, the back surface of the diaphragm overlying the substantially planar surface of the backplate. The diaphragm includes an insulating layer adapted to contact the backplate and a conducting layer electrically isolated therefrom. The diaphragm tensioning arrangement includes means for applying a load to the front surface of the diaphragm in order to maintain diaphragm tension. A groove disposed in the backplate extension or base has at least one groove opening into its front surface. A tension element engages the front surface of the diaphragm pressing a portion thereof into the groove in order to maintain diaphragm tension.

Abstract: Capacitive sound transducer of a very small construction, in particular a microphone has at least two joint semiconductor chips, which embody a membrane unit and a fixed counter-electrode structure. The acoustic active portion of the membrane unit 1 with at least one counter-electrode structure 3, which is separated from the membrane unit by means of an air gap, forms a system which is comparable to a field effect transistor. The membrane unit which is formed of a semiconducting ground material encompasses an acoustically active membrane surface (2), one side 5 of which confronts the counter-electrode structure is electrically conductive.The counter-electrode structure 3 has a semiconductive base material out of which there is machined a channel length which has been limited by a source-drain arrangement, the geometric width measurrement of which is on the order of magnitude of a tenth of the lateral measurement of the active membrane surface.

Abstract: This invention provides an electroacoustic transducer and a method of making it. The transducer according to the invention comprises a substrate of a semiconductor material with a recessed portion. A membrane is stretched across the recessed portion, which membrane is set in vibration in response to an input signal comprising audio and/or ultrasonorous frequencies. A pair of electrodes is provided, which form a capacitor, and between which an electric field is present. The electrodes are so arranged relatively to the membrane that the capacitance of the capacitor can vary under the influence of vibrations of the membrane, so that acoustic signals are converted into electric signals. A layer of an electrically insulating material functions as a carrier for an electric charge to provide an auxiliary electric field between the electrodes.

Abstract: This invention provides an electroacoustic transducer and a method of making it. The transducer according to the invention comprises a substrate of a semiconductor material with a recessed portion. A membrane is stretched across the recessed portion, which membrane is set in vibration in response to an input signal comprising audio and/or ultrasonorous frequencies. A pair of electrodes is provided, which form a capacitor, and between which an electric field is present. The electrodes are so arranged relatively to the membrane that the capacitance of the capacitor can vary under the influence of vibrations of the membrane, so that acoustic signals are converted into electric signals. A layer of an electrically insulating material functions as a carrier for an electric charge to provide an auxiliary electric field between the electrodes.

Abstract: An improvement in a capacitance type electrostatic transducer for transmitting and/or receiving pressure energy, wherein the transducer includes a relatively inflexible backplate with at least one major surface thereof formed of electrically conductive material, a relatively flexible membrane including a layer of electrically conductive material stretched across and coextensive with the one major surface of the backplate, electrically insulating means for maintaining a capacitor forming spacing between the major surface and the stretched membrane and wherein the major surface has protrusions extending through the spacing for supporting the membrane. The improvement is providing the protrusions as a multitude of discrete pedestals distributed over the major surface and formed by etching away the major surface except in photographically selected areas defining the pedestals.

Abstract: A sensor for resolving the left-right ambiguity encountered in horizontal line hydrophone arrays consists of an orthogonal pair of dipole hydrophones, a monopole hydrophone, and a tilt sensor, the tilt sensor connecting the dipole hydrophones so as to provide a single dipole hydrophone which is always oriented horizontally. The tilt sensor consists of two variable capacitors made from hollow cylinders of high permittivity dielectric material, partially filled with a quantity of liquid mercury which forms the variable inner electrodes of the capacitors. The outer electrodes of the capacitors, on the outside of the cylinders, having a sinusoidally-shaped perimeter and being oriented at right angles to each other, are connected to the crossed dipoles in order to provide the required horizontal dipole hydrophone.

Abstract: An acoustic transducer with an improved electret assembly mounting for providing spacings between the fixed and movable electrodes, and having as one feature the lowering of the undesired capacitance therebetween.

Abstract: A broadband megahertz range electrostatic acoustic transducer for use in a liquid environment. A liquid-tight enclosure 11 which includes a metallic conducting membrane 18 as part of its outside surface has a means 19 inside the liquid-tight enclosure for applying a tension to the membrane and for mounting an electrode 23 such that the flat end of the electrode is approximately parallel to the membrane. The invention includes structure and a method for ensuring that the membrane 18 and the flat end of the electrode 23 are exactly parallel and a fixed predetermined distance from each other.

Abstract: An alarm system is provided for detecting a seismic tremor and for generating an audio and/or visual alarm signal which varies depending upon the magnitude of the seismic tremor. In the preferred form of the invention, the alarm system comprises a free running oscillator having a pair of terminals the capacitive value across which controls the frequency of the oscillator. A fixed oscillator plate is electrically connected to one terminal while a variable position oscillator plate is electrically connected to the other terminal and has an inertial mass secured to it. A spring positioned between the plates urges the variable position capacitor plate away from the fixed plate but still enables the variable position capacitor plate to move in response to a seismic tremor thus varying the capacitive value between the terminals and the frequency of the oscillator. The output from the oscillator is coupled through a phase locked loop circuit which tracks the oscillator output.

Abstract: An acoustic transducer with an improved electret assembly mounting for providing spacings between the fixed and movable electrodes, and having as one feature the lowering of the undesired capacitance therebetween.