The Whitaker Corporation

Pennwalt Corporation

Atochem North America, Inc.

Other

Measurement Specialties, Incorporated

Hologic, Inc.

Temple University

Elf Atochem North America, Inc.

Kyung T Park

Minoru Toda

Peter F Radice

John C Henry

Jay A Stein

Kevin William Wilson

Albert Casciotti

Mitchell L Thompson

Kumar Ogale

William Blaine Powers

Edward Tom

Klaus Kubierschky

Joseph V Chatigny

Takaki Naito

R Fredrick Gastgeb

Hong Wang

Gregory Daniels

Ryuichi Oshima

Richard D Klafter

Glen MacGibbon

Mitchell L Thomspon

Dick Cabral

A system and method for ultrasonic touch switch combined with piezoelectric touch mode is described. The sensor structure may be embodied as a substrate with a piezoelectric element at the back surface of the substrate, with the front surface being a touch sensitive surface. Both operational modes are possible by use of the same sensor element with filtering of the signals so that different advantages of two modes are combined, while disadvantages of either mode are mitigated. The tolerance of substrate thickness of ultrasonic touch mode is improved by use of a wide range of frequency deviation of drive signal by filtering out the fundamental modulation frequency from the output signal and wherein only sharp pulses corresponding to abrupt impedance changes of the piezoelectric element are extracted. The amplitude of the sharp pulses decreases with touching the front surface of substrate. At the same time pressure force applied to the front surface causes the substrate to undergo bending displacement and causes piezoelectric element expansion strain to generate voltage. These two modes are combined and used to control switch of appliance or equipment.

Ultrasonic and strain dual mode sensor for contact switch

Ultrasonic bone testing apparatus including a pair of spaced piezoelectric copolymer transducers for transmitting and receiving ultrasonic energy through a bone-containing portion of a human or other animal disposed between the transducers, and circuitry for detecting an electrical signal generated by the receiving transducer in response to reception of ultrasonic energy. The transducers are disks of the copolymer supported by rigid rings spaced inwardly of their peripheries. A method of determining a characteristic of bone in a bone-containing portion of an animal includes positioning a pair of piezoelectric copolymer ultrasonic transducers respectively on opposite sides of, and ultrasonically coupling both transducers to, the animal portion, and transmitting ultrasonic energy through the animal portion including the bone to be tested from one transducer to the other. The animal portion may be a human heel.

Ultrasonic bone testing with copolymer transducers

The present invention provides a low-cost piezoelectric cable and wire harness using the same, which offer a high connection reliability without picking up interference signals in areas where the cable acts as a sensor. Coaxial piezoelectric cable 10 has a piezoelectric material layer 14 disposed between a core conductor 12 and an outer conductor 16. Piezoelectric material layer 14 is polarized and shows piezoelectric properties in a region 20 which extends along a window frame 2 of an automobile, but is not polarized, and therefore shows no piezoelectric properties, in a region 22 in which it is not desired that the cable act as a sensor. Accordingly, there is no pick-up of false signals in the region 22.

Piezoelectric cable and wire harness using the same

A touch sensitive switch is fabricated from a substrate having a touch region on a first surface and a piezoelectric element on a second surface of the substrate. The piezoelectric element is driven by a signal configured so that an ultrasonic wave generated by the element is transmitted into the substrate and is reflected back and forth into the substrate at both surfaces. A touch changes the reflectivity at the first surface, and influences the impedance of the transducer assembly which is comprised of the piezoelectric element and the substrate.

Reflective mode ultrasonic touch sensitive switch

A transducer assembly for a proximity sensor which comprises an elongated polymer piezoelectric film (16). The film is supported as an elongated series of arcuate segments which are curved in the same direction and have the same radius of curvature. Electrodes (18) on both sides of the piezoelectric film form opposed pairs, each pair being associated with a respective arcuate segment. The electrodes are utilized for applying a varying electric field across the thickness of the film to cause an ultrasonic acoustic wave to be radiated from the film.

Proximity sensor utilizing polymer piezoelectric film

An ultrasonic proximity sensor particularly suited for outdoor environments having a transducer including a polymer piezoelectric film bonded to a protective metal layer. The transducer is mounted in the sensor housing so that the protective metal layer is exposed to the environment through a window of the sensor housing. The transducer can be implemented as an asymmetric bimorph structure, having an electrode bonded to a surface of the polymer piezoelectric film opposite the protective metal layer and between support members. Deformation of the polymer piezoelectric film between the protective metal layer and the electrode occurs upon application of a voltage thereto, generating an ultrasonic wave. The transducer can also be used as a receiver, generating an output voltage from the electrode upon impingement of an ultrasonic wave upon the protective metal layer. The transducer can also be implemented as a curved length mode transducer including an arcuate shaped support member for supporting the polymer piezoelectric film to be curved between the support members. The radius of the curved length mode transducer is selected so that the transducer can be resonant at the resonance frequency of the curved length mode, therefore vibrating at high frequency to generate an ultrasonic wave.

Proximity sensor utilizing polymer piezoelectric film with protective

A short distance ultrasonic distance meter is disclosed with provisions to reduce the ill-effects of ringing when measurements are of obstacles closer than about ten inches. In one embodiment an opposite phase ultrasonic wave is introduced by a circuit (245) and in another embodiment a strain sensor (232) introduces negative feedback to effect cancellation of ringing (147). Finally, in a third embodiment, both the negative feedback and opposite phase methods are employed for optimal results.

Short distance ultrasonic distance meter

An ultrasonic distance meter cancels out the effects of temperature and humidity variations by including a measuring unit and a reference unit. In each of the units, a repetitive series of pulses is generated, each having a repetition rate directly related to the respective distance between an electroacoustic transmitter and an electroacoustic receiver. The pulse trains are provided to respective counters, and the ratio of the counter outputs is utilized to determine the distance being measured.

Ultrasonic distance meter

A piezoelectric detecting system for detecting the opening of an enclosure without the need of an external battery or electrical system is disclosed. Several different piezoelectric sensor configurations to effect the detecting system are disclosed.

Penetration detection system

A piezoelectric snap action switch for connecting at least two conductive elements via first and second upwardly convex snap action plates disposed in an overlapping manner with respect to each other and respectively connected to the respective conductors. A piezoelectric polymer film with electrodes on respective surfaces thereof is disposed between the snap action plates so that upon depression of the snap action plates the piezoelectric polymer film is caused to extend or contract along a surface thereof so as to conduct an electrical signal between the electrodes on its respective surfaces. The electrical signal is then conducted between the conductors via the electrodes by electrically coupling the electrodes to the snap action plates. The resulting structure is quite rigid so that the switch is virtually insensitive to vibration, and because of the plural snap action plates, metal lead attachment is greatly facilitated.

Piezoelectric snap action switch

An electroacoustic novelty, particularly to the brim on an article of headware, or to a flag, containing a piezoelectric polymer film, where means are electrically coupled with electrodes on the film for applying an audio-frequency signal voltage across the film to cause the film to vibrate and emit sound waves.

Electroacoustic novelties

A device is disclosed for detecting the presence and direction of air flow through a passageway having a first opening and a second opening for air to flow therethrough in either a first direction or a second direction. The device comprises a piezoelectric sensor located within the passageway. A flow director is provided within the passageway for directing air flow through the passageway for impingement upon the sensor. The sensor generates a first electrical signal when air flows through the passageway in the first direction and a second electrical signal when air flows through the passageway in the second direction. A discriminator is electrically connected to the sensor for receiving the first and second electrical signals and for discriminating between the two signals to identify the direction of air flow through the passageway.

Device for detecting air flow through a passageway

Electroacoustic novelties are disclosed having a piezoelectric polymer film which functions as a speaker or microphone. The novelties include flags, banners, posters or articles of headwear. The piezoelectric polymer film may be attached to a portion of the flexible substrate forming the novelty, or it may be used as an integral part of the novelty structure. An audio output or recording device is electrically coupled to the piezoelectric polymer film. Both the piezoelectric polymer film and the electrodes may be transparent so that the adjoining portion of the novelty is visible.

A structure for a piezo film impact detector eliminates or minimizes false outputs due to pyroelectric effects. The detector structure has particular application to outdoor and underground use.

Piezofilm impact detector with pyro effect elimination

A piezoelectric transducer array comprises a plurality of piezoelectric transducer means arranged in an array. A common electrode is provided among at least a plurality of the piezoelectric transducer means. A plurality of discrete signal electrodes is operatively associated with each transducer means. The number of signal electrodes for each transducer means is the same. The surface areas of the signal electrodes for each transducer means are adapted and arranged for generating a signal unique to each transducer means. Corresponding ones of the signal electrodes of each plurality of signal electrodes are connected together with a common conductor to form a single electrical terminal. The total number of resulting electrical terminals is the same as the number of signal electrodes for each transducer means.

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Berwyn, PA, United States of America

Kyung T Park