Electret Patents (Class 367/170)
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Patent number: 11196358Abstract: An automatic powering device includes a dielectric layer, a driving layer, a plurality of electrodes and a droplet. The dielectric layer includes a first surface and a second surface opposite to the first surface. The driving layer faces toward the dielectric layer thereby forming a channel between the driving layer and the dielectric layer. The driving layer includes a plurality of hydrophilic surfaces facing toward the first surface and a plurality of hydrophobic surfaces facing toward the first surface. Each of the hydrophilic surfaces is staggered from each of the hydrophobic surfaces. The electrodes are disposed at the second surfaces. The electrodes each are electrically connected to and spaced from each other. The droplet is flowable within the channel. The droplet is affected by the hydrophilic surfaces and the hydrophobic surfaces so as to flow in the channel.Type: GrantFiled: April 9, 2020Date of Patent: December 7, 2021Assignee: NATIONAL TSING HUA UNIVERSITYInventors: Zong-Hong Lin, Da-Jeng Yao, Hsuan-Yu Lin
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Patent number: 11178490Abstract: What is disclosed is a diaphragm for an acoustic AMT transducer. The diaphragm is folded such that the folds form pockets (11 . . . 15), and the pockets next to each other are alternatingly open on one and the other face of the diaphragm. The pockets (11 . . . 15) are dimensioned so that the transformation ratio of the diaphragm velocity to the velocity of the air driven by the pockets in use of the transducer varies steadily from pocket to pocket across the diaphragm. For example, the respective width, depth and/or length of the pockets increases or decreases steadily from pocket to pocket across a plurality of said pockets. The acoustic transducer comprising the diaphragm has a well-balanced frequency characteristic across a wide frequency range.Type: GrantFiled: May 1, 2020Date of Patent: November 16, 2021Assignee: HEDD Audio GmbHInventor: Klaus Heinz
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Patent number: 10160644Abstract: A manufacturing method of a MEMS sensor includes a step of, by irradiating a first hole formed in a second layer on a semiconductor substrate with a focused ion beam for a first predetermined time, forming a first sealing film, which seals the first hole, on the first hole, and a step of, by irradiating a second hole formed in the second layer with a focused ion beam for a second predetermined time, forming a second sealing film, which seals the second hole, on the second hole. At this time, each of the first predetermined time and the second predetermined time is a time in which thermal equilibrium of the second layer is maintainable, and the step of forming the first sealing film and the step of forming the second sealing film are performed repeatedly.Type: GrantFiled: March 12, 2018Date of Patent: December 25, 2018Assignee: Hitachi, Ltd.Inventors: Masaharu Kinoshita, Atsushi Isobe, Kazuo Ono, Noriyuki Sakuma, Tomonori Sekiguchi, Keiji Watanabe
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Patent number: 9664807Abstract: A seismic sensor cable system is provided. The seismic sensor cable system may include a cable, a first sensor configured to measure motion of the cable, wherein measurement of motion by the first sensor substantially excludes particle motion associated with seismic waves, and a second sensor configured to measure particle motion associated with the seismic waves.Type: GrantFiled: September 26, 2014Date of Patent: May 30, 2017Assignee: ION GEOPHYSICAL CORPORATIONInventors: Andre W. Olivier, Matthew Greco, Ronald Barry
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Patent number: 8787601Abstract: A condenser microphone includes a substrate having a cavity, first and second spacers defining an opening, a diaphragm having a rectangular shape positioned inside of the opening, and a plate having a rectangular shape positioned just above the diaphragm. Plate joint portions integrally interconnected with two sides of the plate are directly attached onto the second spacer. Supports, which are attached onto the second spacer across the opening and project inwardly of the opening, are connected to the prescribed portions of the diaphragm via third spacers relatively to the other two sides of the plate. The center portion of the diaphragm can be designed in a multilayered structure, and the peripheral portion can be bent outwardly. In addition, both ends of the diaphragm are fixed in position, while free ends of the diaphragm vibrate due to sound waves.Type: GrantFiled: February 21, 2007Date of Patent: July 22, 2014Assignee: Yamaha CorporationInventors: Toshihisa Suzuki, Yukitoshi Suzuki, Nariyasu Yaguchi, Kazushi Sakurauchi
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Patent number: 8256093Abstract: An acoustic mirror of alternately arranged layers of high and low acoustic impedances is manufactured in that a basic material having a first layer of the layer sequence is initially provided, on which a second layer of the layer sequence is created on the first layer such that the second layer of the layer sequence partially covers the first layer. Subsequently, a planarization layer is applied onto the layer sequence, and the planarization layer is removed in an area which in the common layer plane projects laterally beyond the second layer so as to result in a residual planarization layer. Finally, a termination layer is applied onto the layer sequence and the residual planarization layer.Type: GrantFiled: January 11, 2010Date of Patent: September 4, 2012Assignee: Avago Technologies Wireless IP (Singapore) Pte. Ltd.Inventor: Gernot Fattinger
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Patent number: 7971337Abstract: The production of a hearing aid device can be simplified by the use of a microphone module with a plurality of microphones. To attach and electrically contact the microphones, the invention provides a microphone carrier with three-dimensionally directed conductor traces in MID technology. In a complicated microphone arrangement with a plurality of microphones, a single microphone module can thereby be used on which all microphones of the hearing aid device are attached and electrically connected.Type: GrantFiled: July 2, 2007Date of Patent: July 5, 2011Assignee: Siemens Audiologische Technik GmbHInventors: Holger Kral, Joseph Sauer, Markus Trautner
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Patent number: 7926163Abstract: An oscillator device having an oscillating member, a resilient support and a supporting member is produced. The oscillating member is supported by the resilient support for oscillation about an oscillation axis. The oscillating member is formed with a movable element having protrusions for adjusting its mass, the protrusions extending from the movable element parallel to the oscillation axis and being formed in pairs disposed at positions symmetrical with respect to the oscillation axis. A sectional area of each protrusion along a plane perpendicular to the oscillation axis is constant in the oscillation axis direction. A laser beam is projected to a cutting position of protrusions, so as to partly remove the protrusion. The protrusions are cut based on adjusting the cutting position. The sum of the lengths removed from the protrusions by the cutting becomes equal to a predetermined length to thereby adjust an inertia moment of the oscillating member.Type: GrantFiled: June 9, 2009Date of Patent: April 19, 2011Assignee: Canon Kabushiki KaishaInventors: Takahisa Kato, Yukio Furukawa, Takahiro Akiyama
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Patent number: 7925033Abstract: The present invention provides a stable and excellent electro-acoustic transducer having simple constitution with which a vibration pole does not contact with stator poles by a repulsive force acting between the vibration pole and the stator poles and the vibration pole can be stably positioned in place between the two stator poles. A vibration pole is disposed between two stator poles, and surfaces of the vibration pole and the two stator poles facing to each other have electrostatically same polarity to generate an electrostatic repulsive force as a restorative force acting between the vibration pole and the stator poles, so that the vibration pole is positioned in place and electro-acoustic conversion is performed by the vibration displacement of the vibration pole with respect to the stator poles. Whereby, the vibration pole does not contact substantially with the stator poles and the vibration pole is stably positioned in place.Type: GrantFiled: November 24, 2006Date of Patent: April 12, 2011Inventor: Hiroshi Okazawa
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Patent number: 7905006Abstract: Provided is a faceplate for an In-The-Ear (ITE) hearing aid and a method of manufacturing a faceplate for an In-The-Ear (ITE) hearing aid in which the faceplate can be manufactured in a compact size, using a foldable flexible printed circuit board (PCB), while maintaining the quality, enabling mass-production, and reducing the manufacturing cost.Type: GrantFiled: September 25, 2006Date of Patent: March 15, 2011Inventor: You Jung Kwon
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Patent number: 7779696Abstract: A capacitive micromachined ultrasonic transducers (cMUT) system has two cMUTs connected to each other. The first cMUT is adapted for operation in a transmission mode, and the second cMUT is adapted for operation in the reception mode. The first cMUT and the second cMUT share a common signal line and are connected in a manner to allow the first cMUT and the second cMUT to have bias voltages that can be independently set. In one embodiment, one of the cMUTs is connected to a voltage controller to regulator the voltage applied there on. Various connection configurations, including connections in series and connections in parallel, are disclosed. The cMUT system configurations allow separate optimization for transmission and reception and better flexibility in operation.Type: GrantFiled: April 4, 2007Date of Patent: August 24, 2010Assignee: Kolo Technologies, Inc.Inventor: Yongli Huang
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Patent number: 7669310Abstract: An acoustic mirror of alternately arranged layers of high and low acoustic impedances is manufactured in that a basic material having a first layer of the layer sequence is initially provided, on which a second layer of the layer sequence is created on the first layer such that the second layer of the layer sequence partially covers the first layer. Subsequently, a planarization layer is applied onto the layer sequence, and the planarization layer is removed in an area which in the common layer plane projects laterally beyond the second layer so as to result in a residual planarization layer. Finally, a termination layer is applied onto the layer sequence and the residual planarization layer.Type: GrantFiled: October 18, 2006Date of Patent: March 2, 2010Assignee: Avago Technologies Wireless IP (Singapore) Pte. Ltd.Inventor: Gernot Fattinger
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Patent number: 7498699Abstract: An electret and composite formed therewith. The electret includes a polymer, copolymerizing from monomers including VdF as a first monomer and HFP, CTFE, TFE, or combinations thereof as a second monomer.Type: GrantFiled: March 1, 2004Date of Patent: March 3, 2009Assignee: Industrial Technology Research InstituteInventors: Dar-Ming Chiang, Wen-Liang Liu, Jen-Luan Chen, Lon-Cheng Cheng
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Patent number: 7436736Abstract: A hydrophone array includes hydrophones having an electret means and may have TFT FETs to generate current in response to received longitudinal wave signals. The arrangement may also be used to transmit longitudinal wave signals. Storage capacitors may be coupled to each TFT FET output to act as sample and hold means. Digital switches may allow the sample and hold circuit to both reset and measure the output of the hydrophone element. Data lines may be used to indicate the location of the received signal on the longitudinal wave detector sensor array.Type: GrantFiled: August 13, 2007Date of Patent: October 14, 2008Assignee: Ultra-Scan CorporationInventors: John K. Schneider, Jack C. Kitchens
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Patent number: 7412763Abstract: A method of making an acoustic assembly for use in a transducer includes forming a multi-layer assembly. The multi-layer assembly includes a first layer member and a second layer member. Each member includes a center portion, an edge portion and an aperture separating the center portion and the edge portion. The assembly has an assembly stiffness that is greater than the stiffness of either the first or second layer members. A hinge joins the assembled first and second center portions and the first and second edge portions such that the assembled first and second center portions is free to at least partially rotate relative to the assembled first and second edge portions about an axis. A flexible layer member is coupled to the assembly and provides airtight sealing of the passageway.Type: GrantFiled: March 28, 2006Date of Patent: August 19, 2008Assignee: Knowles Electronics, LLC.Inventors: Mekell Jiles, David Earl Schafer, Anthony D. Minervini, Hanny Sunarto, Thomas Edward Miller, Daniel Max Warren
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Patent number: 7204009Abstract: The present invention relates to a semiconductor electret condenser microphone capable of being reduced in size and including an acoustic sensor 100 and a case 200 for accommodating the acoustic sensor 100, the acoustic sensor 100 has a semiconductor chip 110 forming necessary electronic circuits 111A to 111C, and opening a through hole 112 away from the electronic circuits 111A to 111C, an electrode layer 120 formed on the surface of the semiconductor chip 110 away from the through hole 112, an electret member 130 laminated away from part of the electrode layer 120 and through hole 112, and a diaphragm 140 provided with a spacing 160 to the electret member 130, in which the electrode layer 120 exposed from the electret member 130 is connected to the electrode 111a of the electronic circuit 111A through the case 200 (FIG. 6).Type: GrantFiled: July 21, 2005Date of Patent: April 17, 2007Assignee: Hosiden Electronics Co., Ltd.Inventors: Takao Kawamura, Yoshiaki Ohbayashi, Mamoru Yasuda
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Patent number: 7080442Abstract: The present invention relates to a semiconductor electret condenser microphone capable of being reduced in size and including an acoustic sensor 100 and a case 200 for accommodating the acoustic sensor 100, the acoustic sensor 100 has a semiconductor chip 110 forming necessary electronic circuits 111A to 111C, and opening a through hole 112 away from the electronic circuits 111A to 111C, an electrode layer 120 formed on the surface of the semiconductor chip 110 away from the through hole 112, an electret member 130 laminated away from part of the electrode layer 120 and through hole 112, and a diaphragm 140 provided with a spacing 160 to the electret member 130, in which the electrode layer 120 exposed from the electret member 130 is connected to the electrode 111a of the electronic circuit 111A through the case 200 (FIG. 6).Type: GrantFiled: October 21, 2002Date of Patent: July 25, 2006Assignee: Hosiden Electronics Co., Ltd.Inventors: Takao Kawamura, Yoshiaki Ohbayashi, Mamoru Yasuda
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Patent number: 6937735Abstract: A microphone is constructed to be more tolerant to a wide range of relative humidity conditions without adversely affecting the performance of the microphone. The microphone includes a housing with a sound port for receiving sound and an electret assembly for converting the sound into an output signal. The electret assembly includes a diaphragm and a backplate. The backplate is made of at least two layers, usually polymeric layers. The first layer of material has a first hygroscopic coefficient and a second layer of material has a second hygroscopic coefficient. The first and second layers cause the backplate to bend in response to higher humidity conditions, thereby minimizing the adverse effects on microphone performance caused by characteristic changes in the diaphragm at the higher humidity conditions.Type: GrantFiled: August 1, 2002Date of Patent: August 30, 2005Assignee: SonionMicrotronic Néderland B.V.Inventors: Dion I. de Roo, Adrianus M. Lafort, Michel de Nooij, Raymond Mögelin
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Patent number: 6928720Abstract: A surface acoustic wave device includes a piezoelectric substrate and at least one interdigital electrode disposed on the piezoelectric substrate. The interdigital electrode is made of ?-tantalum.Type: GrantFiled: July 30, 2002Date of Patent: August 16, 2005Assignee: Murata Manufacturing Co., Ltd.Inventors: Masato Kobayashi, Masatoshi Nakagawa, Makoto Tose, Toshio Hagi, Toshimaro Yoneda
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Patent number: 6870939Abstract: This invention mainly provides a SMT-type structure of the minimized and low-power silicon-based electret condenser microphone. Primarily integrates with the electret, silicon-based, MEMS and microphone techniques to implement the minimized and low-power silicon-based electret condenser microphone. The Silicon-based bi-diaphragm of the composite diaphragm-chip was coated with the low-dielectric macromolecule material to allow the microphone acquires the sufficient electrical charges. Moreover, the impedance matching element of the microphone that MOSFET was implemented by the MEMS technology. Conclusively, this silicon-based electret condenser microphone gains several achievements as the smallest volume, a lower bias voltage, a SMT-type structure, a lower residue stress and a lower assembly cost.Type: GrantFiled: November 28, 2001Date of Patent: March 22, 2005Assignee: Industrial Technology Research InstituteInventors: Dar-Ming Chiang, Tsung-Lung Yang
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Patent number: 6806593Abstract: An electret formed by micro-machining technology on a support surface, including a self-powered electret sound transducer, preferably in the form of a microphone, formed by micro-machining technology. Each microphone is manufactured as a two-piece unit, comprising a microphone membrane unit and a microphone back plate, at least one of which includes an electret formed by micro-machining technology. When juxtaposed, the two units form a microphone that can produce a signal without the need for external biasing, thereby reducing system volume and complexity. The electret material used is a thin film of spin-on polytetrafluoroethylene (PTFE). An electron gun preferably is used for charge implantation. The electret has a saturated charged density in the range of about 2×10−5 C/m2 to about 8×10−4 C/m2. Thermal annealing is used to stabilize the implanted charge. An open circuit sensitivity of about 0.5 mV/Pa has been achieved for a hybrid microphone package.Type: GrantFiled: May 15, 2001Date of Patent: October 19, 2004Assignee: California Institute of TechnologyInventors: Yu-Chong Tai, Tseng-Yang Hsu, Wen H. Hsieh
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Patent number: 6792123Abstract: An electrostatically operating electroacoustic transducer, operating as a sound receiver and configured to be mounted in a microphone capsule, has an electrode and a diaphragm connected to one another at a spacing from one another by a spacer ring, wherein on the electrode at least one first electric resistor is arranged which is connected to a power supply during operation of the microphone. The resistor is heated to prevent condensation of water vapor, and this improves the resistance of the microphone against ambient humidity.Type: GrantFiled: February 8, 2002Date of Patent: September 14, 2004Assignee: AKG Acoustics GmbHInventor: Gino Pavlovic
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Patent number: 6694032Abstract: 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.Type: GrantFiled: December 27, 2001Date of Patent: February 17, 2004Assignee: BSE Co., Ltd.Inventors: Du-Yeong Yun, Sung-Ho Park
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Patent number: 6678383Abstract: 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.Type: GrantFiled: October 29, 2001Date of Patent: January 13, 2004Assignee: Star Micronics Co., Ltd.Inventors: Motoaki Ito, Yoshio Imahori
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Patent number: 6632178Abstract: 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.Type: GrantFiled: October 27, 2000Date of Patent: October 14, 2003Assignee: Koninklijke Philips Electronics N.V.Inventor: John Douglas Fraser
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Patent number: 6243474Abstract: A small, inexpensive, high quality electret formed by micro-machining technology on a support surface, and further including a small, inexpensive, high quality, self-powered electret sound transducer, preferably in the form of a microphone, formed by micro-machining technology. Each microphone is manufactured as a two-piece unit, comprising a microphone membrane unit and a microphone back plate, at least one of which includes an electret formed by micro-machining technology. When juxtaposed, the two units form a highly reliable, inexpensive microphone that can produce a signal without the need for external biasing, thereby reducing system volume and complexity. In the preferred embodiment, the electret material used is a thin film of spin-on polytetrafluoroethylene (PTFE). An electron gun preferably is used for charge implantation. The electret has a saturated charged density in the range of about 2×105 C/m2 to about 8×10−4 C/m2. Thermal annealing is used to stabilize the implanted charge.Type: GrantFiled: April 18, 1997Date of Patent: June 5, 2001Assignee: California Institute of TechnologyInventors: Yu-Chong Tai, Tseng-Yang Hsu, Wen H. Hsieh
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Patent number: 6201874Abstract: 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.Type: GrantFiled: December 7, 1998Date of Patent: March 13, 2001Assignee: American Technology CorporationInventors: James J. Croft, III, Elwood G. Norris
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Patent number: 6169810Abstract: An electroacoustic transducer of the electret type, having a backplate situated above a diaphragm, with the backplate being provided with spacers. The diaphragm is clamped on a frame-shaped carrier located at an underside of the diaphragm. The carrier is provided with supporting portions which are vertically aligned with the spacers. In one embodiment, supporting posts are formed on the supporting portions to allow the carrier to rest on a case bottom. The resulting electroacoustic transducer can be easily assembled with a reduced risk of damage.Type: GrantFiled: April 15, 1997Date of Patent: January 2, 2001Assignee: Microtronic Nederland, B.V.Inventors: A. Z. van Halteren, E. Wilmink, M. de Blok, O. Geschiere, J. M. van Doorn
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Patent number: 6111966Abstract: 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.Type: GrantFiled: April 10, 1998Date of Patent: August 29, 2000Inventors: Raimund Staat, Claus-Peter Hinke
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Patent number: 5982709Abstract: There is provided an acoustic transducer which includes a membrane of selected size and shape supported at its edges spaced from a first conductive electrode by an integral support structure with the second conductive electrode comprising a thin metal film on the membrane. The active membrane area is undisturbed by etch vias.Type: GrantFiled: March 31, 1998Date of Patent: November 9, 1999Assignee: The Board of Trustees of the Leland Stanford Junior UniversityInventors: Igal Ladabaum, Xuecheng Jin, Butrus T. Khuri-Yakub
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Patent number: 5757090Abstract: A folded dielectric film element is provided which converts energy. The film element includes at least one dielectric film that is bent into folds and provided with electrodes. The electrodes are arranged in the folds so that different electrodes are placed in successive folds. The strength of an electric field increases in one fold and decreases in a successive fold.Type: GrantFiled: March 11, 1996Date of Patent: May 26, 1998Inventor: Kari Kirjavainen
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Patent number: 5548658Abstract: An electret assembly for a microphone is disclosed. The microphone is adapted for use with a hearing aid. The electret assembly comprises a motor ring having first and second opposing peripheral surfaces and an aperture extending therebetween. The motor ring includes four generally co-planer ledges recessed below the first opposing surface and defining a rectangle. A charged plate is disposed on the ledges. The charged plate is substantially flush with the first opposing surface. A flexible diaphragm is secured to the second opposing surface and extending across the aperture. A bead of epoxy secures the charged plate to the motor ring.Type: GrantFiled: June 6, 1994Date of Patent: August 20, 1996Assignee: Knowles Electronics, Inc.Inventors: Eugene M. Ring, William J. Murphy
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Patent number: 5255246Abstract: 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.Type: GrantFiled: September 17, 1992Date of Patent: October 19, 1993Assignee: Siemens Nederland N.V.Inventor: Aart Z. van Halteren
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Patent number: 5046057Abstract: A marine seismic cable comprising a core, a body of flotation material positioned around the core, an acoustic energy transducer positioned proximate the core, and a body of acoustically transparent material positioned around the acoustic energy transducer.Type: GrantFiled: December 10, 1982Date of Patent: September 3, 1991Assignee: Shell Oil CompanyInventor: Albert J. Berni
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Patent number: 4910840Abstract: 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.Type: GrantFiled: July 26, 1989Date of Patent: March 27, 1990Assignee: Microtel, B.V.Inventors: Adrianus J. Sprenkels, Piet Bergveld
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Patent number: 4908805Abstract: 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.Type: GrantFiled: October 27, 1988Date of Patent: March 13, 1990Assignee: Microtel B.V.Inventors: Adrianus J. Sprenkels, Piet Bergveld
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Patent number: 4730283Abstract: 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.Type: GrantFiled: September 15, 1986Date of Patent: March 8, 1988Assignee: Industrial Research Products, Inc.Inventors: Elmer V. Carlson, Peter L. Madaffari
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Patent number: 4653036Abstract: A hydrophone device with one or more very small active spots located on a large continuous ferroelectric sheet, such as PVDF, overcomes many of the problems in prior art constructions associated with the high dielectric constant of various media in which the device is used. Additional improvements include increased signal to noise ratio and a sensitivity independent of the medium properties. The hydrophone device includes a piezoelectrically active sheet stretched and clamped on over the top of a hoop ring. A backing is attached to the back of the hoop ring. A low-dielectric material fills the space between the backing and the sheet. This material eliminates the capacitive loading effect which would otherwise be presented by the medium being probed.Type: GrantFiled: October 23, 1984Date of Patent: March 24, 1987Assignee: The United States of America as represented by the Department of Health and Human ServicesInventors: Gerald R. Harris, Aime S. DeReggi
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Patent number: 4517665Abstract: An acoustically transparent hydrophone probe consisting of a rigid hoop structure in which is secured an assembly of very thin piezoelectric polymer sheet material, such as polyvinylidene fluoride, with one or more very small central sensitive portions. In its simplest form it consists of a single sheet with a small central poled piezoelectric area and with very thin metallic electrodes deposited on the sheet on opposite sides of the piezoelectric area and having fine conductive leads extending from the electrodes and adapted to be connected to a suitable amplifier or transmission line. The sheet is of biaxially stretched material, and is held taut in the hoop structure. Other embodiments may employ multiple sheets. With two sheets, the outermost surfaces are metallized and are at common ground potential, and the inner surfaces have superimposed deposited metallic electrodes with poled piezoelectric areas adjacent thereto.Type: GrantFiled: November 17, 1983Date of Patent: May 14, 1985Assignee: The United States of America as represented by the Department of Health and Human ServicesInventors: Aime S. DeReggi, Gerald R. Harris
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Patent number: 4433400Abstract: An acoustically transparent hydrophone probe consisting of a rigid hoop structure in which is secured an assembly of very thin piezoelectric polymer sheet material, such as polyvinylidene fluoride, with one or more very small central sensitive portions. In its simplest form it consists of a single sheet with a small central poled piezoelectric area and with very thin metallic electrodes deposited on the sheet on opposite sides of the piezoelectric area and having fine conductive leads extending from the electrodes and adapted to be connected to a suitable amplifier or transmission line. The sheet is of biaxially stretched material, and is held taut in the hoop structure. Other embodiments may employ multiple sheets. With two sheets, the outermost surfaces are metallized and are at common ground potential, and the inner surfaces have superimposed deposited metallic electrodes with poled piezoelectric areas adjacent thereto.Type: GrantFiled: November 24, 1980Date of Patent: February 21, 1984Assignee: The United States of America as represented by the Department of Health and Human ServicesInventors: Aime' S. DeReggi, Gerald R. Harris
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Patent number: 4245329Abstract: Elongated receiver of continuous structure for seismic prospecting comprising at least one sensitive assembly having two electrically conducting electrodes on both sides of a deformable element subjected to a permanent electric polarization and an electrically insulating compressible element between the deformable element and one of the electrodes. When used for prospecting on the earth the receiver further comprises masses of heavy material secured to one face of the sensitive assembly.Type: GrantFiled: September 2, 1977Date of Patent: January 13, 1981Assignee: Institut Francais du PetroleInventor: Jean-Claude Dubois
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Patent number: RE33718Abstract: 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.Type: GrantFiled: February 16, 1990Date of Patent: October 15, 1991Assignee: Knowles Electronics, Inc.Inventors: Elmer V. Carlson, Peter L. Madaffari