The present invention relates to transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention also relates to devices including an electroactive polymer to convert between electrical and mechanical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

Electroactive polymer devices

A method and apparatus for estimating a respiratory rate of a patient. The method comprises the steps of recording respiratory sounds of the patient, deriving a plurality of respiratory rates from the recorded sounds using a plurality of respiratory rate estimating methods and applying a heuristic to the plurality of derived respiratory rates, the heuristic selecting one of the derived respiratory rates. The selected respiratory rate is the estimated respiratory rate. The apparatus comprises at least one sensor recording respiratory sounds of the patient, a plurality of respiratory rate processors, each of the processors comprising a respiratory rate calculating method, a heuristic means for selecting one of the calculated respiratory rates and a display means for displaying the selected respiratory as the estimated respiratory rate.

Non-invasive monitoring of respiratory rate, heart rate and apnea

The piezoelectric sound monitor comprises a piezoelectric membrane including an inner face, an outer face, and first and second peripheral portions. The piezoelectric sound monitor further comprises a piezoelectric membrane support structure including an outer face, two first mutually facing membrane-clamping walls, a first electrically conductive area, two second mutually facing membrane-clamping walls, and a second electrically conductive area. The inner face of the piezoelectric membrane is applied to the outer face of the support structure. The first peripheral portion of the piezoelectric membrane is clamped between the two first walls, and the first electrically conductive area is located on one of the two first walls for electrically contacting the inner face of the piezoelectric membrane. The second peripheral portion of the piezoelectric membrane is clamped between the two second walls, and the second electrically conductive area is located on one of the two second walls for electrically contacting the outer face of the piezoelectric membrane.

Piezoelectric biological sound monitor with printed circuit board

An acoustic sensor is configured to provide accurate and robust measurement of bodily sounds under a variety of conditions, such as in noisy environments or in situations in which stress, strain, or movement may be imparted onto a sensor with respect to a patient. Embodiments of the sensor provide a conformable electrical shielding, as well as improved acoustic and mechanical coupling between the sensor and the measurement site.

Acoustic sensor assembly

A physiological acoustic monitoring system receives physiological data from an acoustic sensor, down-samples the data to generate raw audio of breathing sounds and compresses the raw audio. The acoustic monitoring system has an acoustic sensor signal responsive to tracheal sounds in a person. An A/D converter is responsive to the sensor signal so as to generate breathing sound data. A decimation filter and mixer down-samples the breathing sound data to raw audio data. A coder/compressor generates compressed audio data from the raw audio data. A decoder/decompressor decodes and decompresses the compressed audio data into decompressed audio data. The decompressed audio data is utilized to generate respiration-related parameters in real-time. The compressed audio data is stored and retrieved so as to generate respiration-related parameters in non-real-time. The real-time and non-real-time parameters are compared to verify matching results across multiple monitors.

Physiological acoustic monitoring system

A microphone comprises a pair of electroacoustic transducing high polymer piezoelectric semi cylindrical shaped membranes having a single axis of elongation tangent to the curvature mounted in a housing facing each other. The membranes are electrically series connected to each other with a connection between the facing surfaces thereof and are of prescribed polarizations to generate an output which is substantially twice the voltage developed individually from each membrane when said membranes are caused to flex in opposite directions and substantially zero when said membranes are caused to flex in the same direction.

Microphone capable of cancelling mechanical generated noise

PURPOSE:To increase the detecting sensitivity of an objective speaker's voice even if the level and direction of noise are changed during the use of a device and to remove misdetection due to noise by forming a soundless section detecting part and a threshold calculating part and controlling a threshold in accordance with the level and direction of the noise. CONSTITUTION:A subtracted value C and added value D are obtained respectively from the difference and addition between main and submicrophone amplitude values. A soundless section detecting circuit 13 compares the added value D with a soundless section detecting threshold and outputs an ON decision signal or OFF decision signal E to a maximum noise subtracted value holding circuit 14 in case the value D the threshold. Only in the soundless section, the circuit 14 updates the held value, sets up its charging/discharging time constant to a prescribed value and holds a maximum noise subtracted value F at the maximum value of noise amplitude. A threshold calculating circuit 15 forms a threshold G slightly larger than the value F based on a prescribed calculation formula and applies the threshold G to a comparator 9. The circuit 9 compares the value C with the value G and outputs an ON signal H in case of C>G or an OFF signal H in case of C<G to a switching circuit 10. Only when the circuit 10 is ON, sound is outputted from the main microphone.

Sound pickup device

In order to realize beam forming with an identical radiation characteristic over a wide bandwidth, this paper describes a method of design for two-dimensional FIR fan filters with wedge-shaped transition regions. In order to provide excellent amplitude approximations in a wide range from low to high frequencies with different transition range widths, a method based on the two-dimensional Fourier series approximation is used. The approximate amplitude characteristic of the target fan filter for which the widths of the passband and the transition band are specified in proportion to the frequency from the origin is greatly degraded at low frequencies near the origin. To reduce this degradation, the target amplitude characteristic at low frequencies of the fan filter is replaced with a rectangular cross-sectional shape. The width of the rectangular amplitude characteristic is set such that the amplitude of the designed result takes the specified value on the center line. Design examples are given for an axially symmetric fan filter and a diagonally symmetric fan filter. Further, the characteristics of the beam formers using these filters are derived and the effectiveness of the method is demonstrated. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 85(7): 38–49, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1106

A design method of 2D FIR fan filters for wideband beam forming by means of 2D Fourier series approximation

PURPOSE:To control the feeling of distance freely by controlling the sensitivity of a sound collection equipment in response to the sound source distance of an incident sound. CONSTITUTION:Sound is incident from the sound source, a main microphone output signal 21 and a sub-microphone output signal 32 are generated in a main microphone 1 and a sub-microphone 2, the two signals are added by a signal adder 3, from which an addition signal 23 is obtained. An addition signal rectifier smoothing circuit 4 calculates the amplitude of the addition signal to obtain the amplitude 24 of the addition signal, and on the other hand, an output signal 21 of the main microphone is inputted to a main microphone rectifier smoothing circuit 5, from which the amplitude 25 of the main microphone is obtained, and a sub-microphone output signal 22 is inputted to a sub- microphone rectifier smoothing circuit 6, from which the amplitude 26 of the sub-microphone is obtained. The amplitudes 25, 26 are added by an amplitude adder 7 to obtain an added amplitude 27. A divider 8 divides the added amplitude 27 by an addition signal amplitude 24 to obtain the amplitude ratio 28. Then the system gain is controlled by a variable gain amplification circuit 9 in response to the ratio 28.

Sound collecting equipment

PURPOSE:To absorb a signal tone with articulation higher than some value by comparing the level of the signal tone with that of an ambient noise, and interrupting the sound absorption of a microphone forcibly when articulate sound absorption is not carried out because the signal tone is contained in the ambient noise. CONSTITUTION:A signal tone level v1 obtained by a sensor 1 is amplified by amplifiers 3 and 4; the output of the amplifier 3 is supplied to an electronic switch 12, and that of the amplifier 4 is inputted to a BPF6. The output of the BPF6 is processed through the DC conversion of an AC/DC converter 8 to input a DC voltage v1 to a comparator CMP10. An ambient noise level v2 obtained by a sensor 2 by sound absorption is level-adjusted by an element 13, amplified by an amplifier 5, and passed through a BPF7, a DC voltage V2 obtained by an AC/DC converter 9 which processes the output of the BPF7 is inputted to the CMP10. When V1>V2, the CMP10 controls a switch control circuit 11 to turn on the switch S12, and when V1<V2, the circuit 11 is controlled to turn off the S12, interrupting the sound absorption of a signal tone.

Hiroyuki Naono

Papers

Microphone capable of cancelling mechanical generated noise

Sound pickup device

A design method of 2D FIR fan filters for wideband beam forming by means of 2D Fourier series approximation

Sound collecting equipment

Sound absorbing device