The State University of New York

The Research Foundation for the State University

Soundskrit Inc.

Ronald N Miles

Weili Cui

Jian Zhou

F Levent Degertekin

Sahil Kumar Gupta

Stephane Leahy

Ronald Hoy

Iman Moazzen

Colum Gibbons

Shahrzad Towfighian

Mark Pallay

Daniel Robert

Meysam Daeichin

Sanjay Sundermurthy

A dynamic capacitive sensor configuration is disclosed which imposes minimal force and resistance to motion on the moving electrode. Moving electrodes avoid adverse effects of large bias voltages such as pull-in instability, despite arbitrary levels of compliance. This configuration facilitates incorporation of highly compliant and thin electrode materials that present the least possible resistance to motion. This type of material is particularly useful for sensing sound. A large bias voltage can be applied without influencing its motion, e.g., 400 V. The electrical sensitivity to sound is high, e.g., approximately 0.5 volts/pascal, two orders of magnitude greater than typical acoustic sensors.

Multielectrode capacitive sensor without pull-in risk

A microelectromechanical actuator, comprising: a substrate, having a surface; a conductive beam suspended parallel to the substrate, displaceable along an axis normal to the surface of the substrate; a center electrode on the substrate under the beam; a pair of side electrodes on the substrate configured, when charged, to exert an electrostatic force normal to the surface of the substrate on the beam that repulses the beam from the substrate, and exerts a balanced electrostatic force on the beam in a plane of the surface of the substrate, the center conductive electrode being configured to shield the beam from electrostatic forces induced by the side electrodes from beneath the beam, and the center electrode being configured to have a voltage different from a voltage on the beam, to thereby induce an attractive electrostatic force on the beam.

Electrodynamically levitated actuator

Microphones, microphone systems, and methods for capturing and processing sound are described. The microphones and microphone systems may adaptively change the direction from which sound is captured. The microphones and microphone systems avoid the need to provide arrays of microphones, while providing adaptive beamforming without a time delay between each channel of information, and multi-directional sound capture. A dependency between the frequency response and system size is also avoided.

Directional microphone and system and method for capturing and processing sound

A microphone, comprising at least two electrodes, spaced apart, configured to have a magnetic field within a space between the at least two electrodes; a conductive fiber, suspended between the at least two electrodes; in an air or fluid space subject to waves; wherein the conductive fiber has a radius and length such that a movement of at least a central portion of the conductive fiber approximates an oscillating movement of air or fluid surrounding the conductive fiber along an axis normal to the conductive fiber. An electrical signal is produced between two of the at least two electrodes, due to a movement of the conductive fiber within a magnetic field, due to viscous drag of the moving air or fluid surrounding the conductive fiber. The microphone may have a noise floor of less than 69 dBA using an amplifier having an input noise of 10 nV/&#x221a;Hz.

Fiber microphone

A method of forming a micromechanical structure comprising, forming a sacrificial layer on a surface and walls of a trench in a substrate; depositing a structural layer over the sacrificial layer, extending into the trench, selectively etching the structural layer to define a pattern having a boundary, at least a portion of the structural layer overlying a respective portion of the trench being removed and at least a portion of the structural layer extending into the trench being preserved at the boundary; and removing at least a portion of the sacrificial layer from underneath the structural layer, prior to removal of at least a portion of the sacrificial layer extending into the trench at the structural boundary. A micromechanical structure formed by the method is also provided.

Hinged MEMS diaphragm, and method of manufacture thereof

A micromechanical structure, comprising a substrate having a through hole; a residual portion of a sacrificial oxide layer peripheral to the hole; and a polysilicon layer overlying the hole, patterned to have a planar portion; a supporting portion connecting the planar portion to polysilicon on the residual portion; polysilicon stiffeners formed extending beneath the planar portion overlying the hole; and polysilicon ribs surrounding the supporting portion, attached near a periphery of the planar portion. The polysilicon ribs extend to a depth beyond the stiffeners, and extend laterally beyond an edge of the planar portion. The polysilicon ribs are released from the substrate during manufacturing after the planar region, and reduce stress on the supporting portion.

Hinged MEMS diaphragm

Hinged MEMS diaphragm and method of manufacture therof

A rigid, flat plate diaphragm for an acoustic device is illustrated. The internal supporting structure of the diaphragm provides a combination of torsional and translational stiffeners, which resemble a number of crossbars. These stiffeners brace and support the diaphragm motion, thus causing its response to not be adversely affected by fabrication stresses and causing it to be very similar in dynamic response to an ideal flat plate operating in a frequency range that extends well beyond the audible.

Robust diaphragm for an acoustic device

A miniature microphone, comprising a diaphragm, supported for displacement in response to acoustic waves, from which a plurality of projections extend; a plurality of projections extending from a surface; a body, supporting the surface to maintain the plurality of projections from the diaphragm and the plurality of projections from the surface in close proximity; and an electromagnetic sensor adapted to sense an electromagnetic interaction between the plurality of projections from the diaphragm and the plurality of projections from the surface and produce an electrical signal in response thereto. The interaction may be detected substantially without inducing a force which tends to substantially displace the diaphragm, since the electrostatic force is substantially parallel to the diaphragm surface.

Comb sense microphone

A microphone having an optical component for converting the sound-induced motion of the diaphragm into an electronic signal using a diffraction grating. The microphone with inter-digitated fingers is fabricated on a silicon substrate using a combination of surface and bulk micromachining techniques. A 1 mm&#xd7;2 mm microphone diaphragm, made of polysilicon, has stiffeners and hinge supports to ensure that it responds like a rigid body on flexible hinges. The diaphragm is designed to respond to pressure gradients, giving it a first order directional response to incident sound. This mechanical structure is integrated with a compact optoelectronic readout system that displays results based on optical interferometry.

Optical sensing in a directional MEMS microphone

A miniature microphone comprising a diaphragm compliantly suspended over an enclosed air volume having a vent port is provided, wherein an effective stiffness of the diaphragm with respect to displacement by acoustic vibrations is controlled principally by the enclosed air volume and the port. The microphone may be formed using silicon microfabrication techniques and has sensitivity to sound pressure substantially unrelated to the size of the diaphragm over a broad range of realistic sizes. The diaphragm is rotatively suspend for movement through an arc in response to acoustic vibrations, for example by beams or tabs, and has a surrounding perimeter slit separating the diaphragm from its support structure. The air volume behind the diaphragm provides a restoring spring force for the diaphragm. The microphone's sensitivity is related to the air volume, perimeter slit, and stiffness of the diaphragm and its mechanical supports, and not the area of the diaphragm.

Miniature non-directional microphone

A method of forming a miniature, surface micromachined, differential microphone, comprising depositing a sacrificial layer on a surface of a silicon wafer; depositing a diaphragm material on a surface of the sacrificial layer; etching the diaphragm material layer to isolate a diaphragm; and removing a portion of the sacrificial layer beneath the defined diaphragm. A diaphragm formed in the diaphragm material layer is supported by a hinge and otherwise isolated from a remaining portion of the diaphragm material layer by a slit adjacent a perimeter of the diaphragm. An enclosed back volume beneath the diaphragm has a depth defined by a thickness of the sacrificial layer, and communicates with an external region via the slit. A transducer may be provided for producing an electrical signal responsive to a displacement of the diaphragm.

Surface micromachined differential microphone

A differential microphone having a perimeter slit formed around the microphone diaphragm that replaces the backside hole previously required in conventional silicon, micromachined microphones. The differential microphone is formed using silicon fabrication techniques applied only to a single, front face of a silicon wafer. The backside holes of prior art microphones typically require that a secondary machining operation be performed on the rear surface of the silicon wafer during fabrication. This secondary operation adds complexity and cost to the micromachined microphones so fabricated. Comb fingers forming a portion of a capacitive arrangement may be fabricated as part of the differential microphone diaphragm.

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Newark Valley, NY, United States of America

Ronald N Miles