Bell Telephone Laboratories

The University of Texas System

Johns Hopkins University

At&t Bell Laboratories

Ilene J Busch-Vishniac

James Edward West

Robert L Wallace, Jr

Vladimir Mancevski

Michael S Yu

Wanjun Wang

Dawnielle Farrar

Alvin B Buckman

Robert A Kubli

David A Berkley

W Stewart Lindenberger

Dahong Qian

Janardhan K Pavuluri

Dahong Oian

Piezoelectric compositions are provided wherein mechanical and piezoelectric properties can be separately modulated. Preferred compositions include resin blends that comprise: (a) a piezoelectrically active polymer and (b) a matrix polymer, methods of making, and use of such resin blends. Advantages of preferred resin blends of the invention can include high piezoelectricity, mechanical strength and flexibility, convenient fabrication process, and high sensitivity at high temperatures.

Piezoelectric compositions

Optical and computational components are combined to form a high precision, six degree-of-freedom, single-sided, noncontact position measurement system. Reflective optical targets are provided on a target object whose position is to be sensed. Light beams are directed toward the optical targets, producing reflected beams. Electrical signals are produced indicating the points of intersection of the reflected beams and the position-sensitive detectors. The position sensitive detectors may be lateral-effect photodiodes. The signals are transformed to provide measurements of translation along and rotation around three nonparallel axes which define the space in which the target object moves.

Noncontact position measurement system using optical sensors

Optical and computational components are combined to form high precision, six degree-of-freedom, single-sided, noncontact position measurement systems. Reflective optical targets are provided on a target object whose position is to be sensed. Light beams are directed toward the optical targets, producing reflected beams. Electrical signals are produced by movements of reflected beams across position-sensitive detectors, such as lateral-effect photodiodes. The signals are transformed to provide measurements of translation along and rotation around three nonparallel axes which define the space in which the target object moves.

Noncontact position measurement systems using optical sensors

A back electrode has a plurality of ridges on one surface. An electret foil is spaced from the ridged surface of the back electrode. In the absence of applied pressure, a gap remains between the foil and the surface of the back electrode between the ridges. Above one applied pressure, the foil collapses between the ridges. Below a second applied pressure, the foil returns to its original position.

Electret transducer for blood pressure measurement

Disclosed is an electroacoustic transducer, such as a microphone, which may be integrated into a semiconductor chip and a method of fabrication. The semiconductor is etched to produce a membrane having a sufficiently small thickness and an area so as to vibrate at audio frequencies. Electrodes are provided in relation to the membrane so that an electrical output signal can be derived from the audio frequencies, or vice versa, due to variable capacitance. Preferably, the sensitivity of the device is made to be an approximately linear function of sound pressure level to be compatible with amplification.

Integrated capacitive transducer

An electret transducer for producing a directional response, electret foil (92) and a backplate (94) with the actual air gap thickness therebetween varying in accordance with a predetermined relationship. The sensitivity of the electret transducer varies inversely as the actual air gap thickness. In one embodiment the actual air gap thickness is realized by a plurality of posts (90) having heights varying according to the aforesaid relationship. In another embodiment, the actual air gap thickness is realized by varying the thickness of the aforesaid backplate.

Electret transducer with variable actual air gap

An electret transducer comprises an electrostatically charged electret foil (10) superimposed directly over a selectively metalized rough surface (16) of a backplate (18). Selective metalization is realized by depositing a thin metal layer (20), the contour of which is defined by a predetermined relationship, over the rough surface (16). The sensitivity of the electret transducer at any point thereon is directly proportional to the width of the metal layer on the backplate. The response characteristic of the electret transducer comprises a main lobe and a plurality of sidelobes below a preselected threshold.

Electret transducer with a selectively metalized backplate

A directional electret transducer comprises an electret foil and a metalized backplate the effective air gap thickness therebetween varying according to a predetermined relationship. The sensitivity of the electret transducer is directly proportional to the effective air gap thickness. The effective air gap thickness is realized in three ways: first, a plurality of equal diameter holes are drilled to varying depths in the aforesaid backplate; second, a plurality of holes of varying diameters are drilled through the aforesaid backplate; third, a plurality of equal diameter holes are drilled through the aforesaid backplate, the density of the holes varying. In each of the aforesaid three ways, the variation is according to the predetermined relationship.

Electret transducer with variable effective air gap

An acoustic transducer for producing highly directional characteristics comprises a metalized backplate (130) facing the flat surface (134) of an electrostatically charged electret foil (132). The thickness of the electret foil varies along the length thereof according to a predetermined relationship. The sensitivity of the electret transducer varies directly with the thickness of the electret foil.

Electret transducer with variable electret foil thickness

An electret transducer for producting a highly directional response characteristic comprises a backplate (18) and, superimposed thereon, an electrostatically charged electret foil (10). The electrostatic charge varies according to a predetermined relationship. The sensitivity of the electret transducer, at any point thereon, is directly proportional to the electrostatic charge on the electret foil at that point.

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Highland Park, NJ, United States of America

Ilene J Busch-Vishniac