A method of operating electro-acoustical transducers such as PMUTs involves applying to the transducer an excitation signal over an excitation interval, acquiring at the transducer a ring-down signal indicative of the ring-down behavior of the transducer after the end of the excitation interval, and calculating, as a function of said ring-down signal, a resonance frequency of the electro-acoustical transducer. A bias voltage of the electro-acoustical transducer can be controlled as a function of the resonance frequency. An acoustical signal received can be transduced into an electrical reception signal and a damping parameter of the electro-acoustical transducer can be calculated as a function of the ring-down signal so that a cross-correlation reference signal can be synthesized as a function of the resonance frequency and the damping ratio of the electro-acoustical transducer. Such a cross-correlation reference signal can be used for cross-correlation with the electrical reception signal to improve the reception quality.

An ultrasonic imaging system has a bias-switchable, ultrasonic transducer array and a bipolar voltage source. The array has a dielectric layer having a top surface and a bottom surface; top and bottom electrode strips in electrical contact with the top and bottom surface of the dielectric layer, the bottom electrode strips being oriented at a non-zero angle relative to the top electrode strips. There is an acoustic matching layer or multiplicity of matching layers on the front-side of the array and a leakage-current mitigation layer. The bipolar voltage source is connected to each of the top and bottom electrode strips to induce a polarization in the dielectric layer, the bipolar voltage source being capable of switching between a high voltage state and a low voltage state. A controller controls the bipolar voltage source, and pulsing to and receiving signals from the top and bottom electrode strips.

Disclosed are a flexible vibration cushion and a method of controlling the same. The flexible vibration cushion may include a cover member, a first soft filler material filled in the cover member; and a vibration generation device including components made of a soft material and disposed in the soft filler. The vibration generation device is configured to generate vibration as an electrostatic force is repeatedly generated and released. The vibration generation device may be applied in a vehicle part, e.g., headrest, thereby minimizing the foreign body sensation acting on the user’s skin while delivering soft and various senses of vibrations to the user.

A method of operating electro-acoustical transducers such as PMUTs involves applying to the transducer an excitation signal over an excitation interval, acquiring at the transducer a ring-down signal indicative of the ring-down behavior of the transducer after the end of the excitation interval, and calculating, as a function of said ring-down signal, a resonance frequency of the electro-acoustical transducer. A bias voltage of the electro-acoustical transducer can be controlled as a function of the resonance frequency. An acoustical signal received can be transduced into an electrical reception signal and a damping parameter of the electro-acoustical transducer can be calculated as a function of the ring-down signal so that a cross-correlation reference signal can be synthesized as a function of the resonance frequency and the damping ratio of the electro-acoustical transducer. Such a cross-correlation reference signal can be used for cross-correlation with the electrical reception signal to improve the reception quality.

A dielectric elastomer vibration system includes a dielectric elastomer vibrator with a dielectric elastomer layer and a pair of electrode layers, and a power supply device producing a potential difference across the electrode layers. The vibrator exhibits various modes or regions of relationship between potential difference and deformation induced by the potential difference: a high-response region in which a relatively large deformation is induced; a low-response region of lower-potential difference in which a relatively small deformation is induced; and a low-response region of higher-potential difference in which a relatively small deformation is induced or in which a break point of the dielectric elastomer layer is included. The power supply device produces the potential difference by applying across the electrode layers a vibration signal voltage, which is generated by combining an AC voltage with a bias DC voltage corresponding to a potential difference falling in the high-response region.

A method of operating electro-acoustical transducers such as PMUTs involves applying to the transducer an excitation signal over an excitation interval, acquiring at the transducer a ring-down signal indicative of the ring-down behavior of the transducer after the end of the excitation interval, and calculating, as a function of said ring-down signal, a resonance frequency of the electro-acoustical transducer. A bias voltage of the electro-acoustical transducer can be controlled as a function of the resonance frequency. An acoustical signal received can be transduced into an electrical reception signal and a damping parameter of the electro-acoustical transducer can be calculated as a function of the ring-down signal so that a cross-correlation reference signal can be synthesized as a function of the resonance frequency and the damping ratio of the electro-acoustical transducer. Such a cross-correlation reference signal can be used for cross-correlation with the electrical reception signal to improve the reception quality.

A method of operating electro-acoustical transducers such as PMUTs involves applying to the transducer an excitation signal over an excitation interval, acquiring at the transducer a ring-down signal indicative of the ring-down behavior of the transducer after the end of the excitation interval, and calculating, as a function of said ring-down signal, a resonance frequency of the electro-acoustical transducer. A bias voltage of the electro-acoustical transducer can be controlled as a function of the resonance frequency. An acoustical signal received can be transduced into an electrical reception signal and a damping parameter of the electro-acoustical transducer can be calculated as a function of the ring-down signal so that a cross-correlation reference signal can be synthesized as a function of the resonance frequency and the damping ratio of the electro-acoustical transducer. Such a cross-correlation reference signal can be used for cross-correlation with the electrical reception signal to improve the reception quality.

A dielectric elastomer vibration system includes a dielectric elastomer vibrator with a dielectric elastomer layer and a pair of electrode layers, and a power supply device producing a potential difference across the electrode layers. The vibrator exhibits various modes or regions of relationship between potential difference and deformation induced by the potential difference: a high-response region in which a relatively large deformation is induced; a low-response region of lower-potential difference in which a relatively small deformation is induced; and a low-response region of higher-potential difference in which a relatively small deformation is induced or in which a break point of the dielectric elastomer layer is included. The power supply device produces the potential difference by applying across the electrode layers a vibration signal voltage, which is generated by combining an AC voltage with a bias DC voltage corresponding to a potential difference falling in the high-response region.

An ultrasound array system has an array of transducer elements made from bias-sensitive material, each transducer element comprising at least a first sub-element and a second sub-element. A series of column electrodes is patterned in columns on a first surface of the array of transducer elements. A series of row electrodes is patterned in rows on a second surface of the array. The rows are at an angle relative to the columns, wherein, for each transducer element, the first sub-element and the second sub-element are connected to different row electrodes. A controller is connected to selectively apply voltage signals to the series of column electrodes and the series of row electrodes. The controller is programmed to apply a first voltage signal to the first sub-element and a second voltage signal to the second sub-element that is distinct from the first voltage signal.

An ultrasound array system has an array of transducer elements made from bias-sensitive material, each transducer element comprising at least a first sub-element and a second sub-element. A series of column electrodes is patterned in columns on a first surface of the array of transducer elements. A series of row electrodes is patterned in rows on a second surface of the array. The rows are at an angle relative to the columns, wherein, for each transducer element, the first sub-element and the second sub-element are connected to different row electrodes. A controller is connected to selectively apply voltage signals to the series of column electrodes and the series of row electrodes. The controller is programmed to apply a first voltage signal to the first sub-element and a second voltage signal to the second sub-element that is distinct from the first voltage signal.