Raytheon Company

David T Wilson

Roger H Tancrell

William W Stoner

Harrison H Barrett

Joseph Callerame

Neil T Dionesotes

Paul F Roman

A composite sensor includes at least one layer comprising a piezoelectric material such as a molecularly poled polymer material or a ceramic material having disposed therebetween a material which enhances the piezoelectric properties of the piezoelectric material. One pair of edges of said composite sensor are constrained from expanding in response to a force applied to the sensor.

Low cost composite transducer

A transducer having an energy conversion medium for converting changes in applied mechanical energy into corresponding changes in thermal energy and a pyroelectric material in thermal energy transfer relationship with the energy conversion medium for producing an electrical output substantially in response to the converted thermal energy. Such transducer is particularly useful as a hydrophone in detecting low frequency sound waves emitted by, or reflected from, underwater objects.

Transducer

A sheet of polymer material is secured between a pair of clamp members. The sheet is directed through a localized heated region to provide a localized heated portion of said sheet. A first one of said clamp members is pulled away from a second fixed clamp member to stretch said sheet providing a pair of neckdown region portions and a reduced thickness portion or stretched portion of the sheet. One of the neckdown regions propagates along unstretched portions of the sheet as the clamp member moves away from the fixed clamp member. The propagating neckdown region is kept within the localized heated region by moving the localized heated region and an electric field is applied to the propagating neckdown region portion to polarize the sheet.

Method of stretching and polarizing polymer materials

A sheet of polymer material is secured between a pair of clamping members. The sheet is directed through a localized heated region to provide a localized heated portion of said sheet. A first one of said clamping members is pulled away from the second clamping members to stretch said sheet and create from the localized heated portion of said sheet a neck-down region. The neck-down region separates providing a pair of neck-down region portions and a reduced thickness portion or stretched portion of the sheet between said neck-down region portions. One of said neck-down regions propagates along unstretched portions of the sheet as the movable clamping member moves away from the fixed clamping member while the other neck-down region remains adjacent the fixed member. This propagating neck-down region portion of the sheet is kept within the localized heated region by moving the localized heated region at a rate related to the rate which unstretched material of the sheet is fed into the neck-down region portion. While the neck-down region portion is maintained within the localized heated region, an electric field is applied to the neck-down region portion to polarize the film.

Sheets of stretched and polarized polymer materials and method of

A method for forming sheets of polarized PVDF into non-planar shaped bodies is described. The technique includes the steps of shaping the polymer material by disposing a sheet of the polymer material about a non-planar surface and subjecting the sheet of polymer material and said non-planar surface to an elevated temperature for a predetermined period of time until said non-planar shape is permanently imparted to the sheet of molecularly polarized polyvinylidenefluoride material.

Method of forming a molecularly polarized polmeric sheet into a

A probe detects sonic energy in liquids and in materials containing liquids such as the flesh of living beings, the probe being particularly adapted for medical ultrasonics. The probe is constructed of materials having acoustic impedances substantially equal to that of water to maximize the transfer of sonic energy in a living being to an electric signal within the probe for accurate detection of high frequency pulses having a duration less than a microsecond. A piezoelectric polymer serves as the transducer and is mounted at the end of the probe housing between a thin metallic window which serves as one electrode, and a metallized rubber rod which serves as the second electrode and sonically insulates the transducer from the housing. An acoustically absorbent ring affixed to the perimeter of the face of the probe, and a flaring of the back end of the probe, reduce the diffraction and reflection of acoustic waves for improved accuracy in the measurement of submicrosecond pulses.

Polymeric piezoelectric microprobe with damper

An imaging system utilizing a scintillation camera for photographing subjects emitting gamma and X-radiation. Masks are sequentially positioned between the subject and the camera to produce a sequence of shadowgrams upon the face of the camera. Output signals of the camera are summed together to give an array of sum signals, the array of sum signals being Fourier transformed followed by a matched filtering by multiplication of the frequency terms by an array of factors utilized in generating the masks. Phase factors are applied to the camera output signals, either before the Fourier transformation or during the matched filtering, the phase factors identifying the masks utilized in producing the respective shadowgrams. An inverse Fourier transformation then results in an image of the subject.

Multiple masking imaging system

A radiographic camera of the form employing a scintillator for producing optical photons in response to incident gamma and X-radiation, a collimator positioned between a subject emitting such radiation and the scintillator for guiding the radiation to the scintillator, and a detector of optical photons for signaling the positions of points of impingement of quanta of the incident radiation upon the scintillator to produce an image of the subject, the improvement being a Fresnel focussing means located alongside the scintillator for directing the optical photons to the detector. The Fresnel focussing means takes the form of a segmented mirror at the front surface of the scintillator and a Fresnel lens at the back surface of the scintillator.

Focussed radiographic camera

A nuclear imaging system in which a substantially on-axis Fresnel zone plate positioned between a source of nuclear radiation in living tissue and a spatial detector is moved in a predetermined time sequence in synchronism with motion of a bar pattern formed at the spatial detector output to improve suppression of unwanted spatial frequency components and to facilitate production of an image of the nuclear source.

Growing community of inventors

Billerica, MA, United States of America

David T Wilson