USA As Represented by Secretary of the Navy

The United States of America As Represented by the Department of Health

Other

Government of the United States of America, As Represented by the Secretary of Commerce

Aime S DeReggi

Seymour Edelman

Gerald R Harris

Stanley A Fisher

George T Davis

Chwan-Kang Chiang

A tubular prosthesis formed by an assembly of electrode segments enclosing n elongated inner chamber, is inserted into the inner ear of a patient for piezoelectric generation of electrical impulses and localized injection thereof in response to externally generated sound waves. Such electrical impulses are applied from the prosthesis to nerve endings adjacent to cochlea contact locations on the electrode segments so as to improve hearing adversely affected by biological damage to the inner ear.

Passive piezoelectric prosthesis for the inner ear

Superconductor-polymer composite materials comprise a matrix formed of a rmoplastic polymer and a superconductor powder dispersed in the matrix. The superconductor powder preferably has a composition RBa.sub.2 Cu.sub.3 O.sub.7-x wherein R is a rare earth metal and x is less than or equal to 1. The thermoplastic polymer matrix comprises a vinylidene fluoride homopolymer or copolymer. The composite materials may be formed as shaped products, sheets or films.

Superconductor-polymer composites

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.

Transducer hydrophone with filled reservoir

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. The electrodes have superimposed deposited metallic leads which have a common electrical connection to a transmission line or to an amplifier. With four sheets, the two innermost sheets form a bilaminate subassembly similar to the 2-sheet embodiment. The outer sheets have metallized outer surfaces which are grounded. Between said outer sheets and the bilaminate subassembly, guard rings coaxial with the piezoelectric active areas are provided. The guard rings can be driven electrically in a manner to eliminate the effects of the capacitance of the electrical leads.

Acoustically transparent hydrophone probe

A sound producing diaphragm of low density, low heat capacity, a large coefficient of thermal expansion and a large Young's modulus is located adjacent the end of an optical fiber transmission line element which is adapted to propagate modulated light and transmit the light outwardly therefrom particularly from the end region thereof to the surface of the diaphragm. The diaphragm absorbs light transmitted from the end region of the fiber optical element which heats and cools in response to the light energy absorbed thereby to expand and contract and produce a sound field. As a transducer in a telephone receiver, the diaphragm is mounted in the earpiece with the end of the optical fiber transmission line located in close proximity thereto and having an enlarged end which includes an anti-reflective coating so that light propagated along the fiber is transmitted to the diaphragm and not reflected back down the fiber.

Opto-acoustic transducer for a telephone receiver

Apparatus and method for detecting pressure variations because of acoustic aves by modulating a preset tensile stress in a stretched thin sheet of a piezoelectric polymer. The modulation is provided by the changing stress caused by an impinging acoustic signal or the like. The piezoelectric polymer sheet under a preset tension acts effectively as a membrane resulting in a high output combined with a high resonance frequency and a wide operating frequency range.

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Boyds, MD, United States of America

Aime S DeReggi