Abstract: Systems and methods of audio processing and control for improved audibility and performance in a parametric loudspeaker system. The parametric loudspeaker system includes a parametric loudspeaker providing a capacitive load, an output stage having a plurality of switches interconnected in a bridge configuration and connected to the capacitive load of the parametric loudspeaker, and a controller operative to generate a series of pulse width modulation (PWM) pulses, and to generate a plurality of control signals synchronized with the series of PWM pulses for switchingly controlling the plurality of switches in the bridge configuration, thereby driving the capacitive load of the parametric loudspeaker.

Abstract: An ultrasonic transducer including a membrane film and a perforated baseplate. The baseplate can have a conductive surface with a plurality of perforations formed through the baseplate. The membrane film can have a conductive surface and be positioned under tension proximate to the perforations formed through the baseplate. The tension of the membrane film can be controlled to provide a restoring force to counteract the moving mass of the membrane film, and the moving mass of air in the perforations of the baseplate. By selecting the diameter(s) of the perforations of the baseplate, the thickness of the baseplate, the thickness of the membrane film, the tension of the membrane film, and/or the bending stiffness of the membrane film, a wide bandpass frequency response of the ultrasonic transducer centered at an ultrasonic frequency of interest can be obtained and tailored to a desired application.

Abstract: A personal communications device that employs directional or parametric speakers to provide an enhanced user experience, delivering audio directly to a user of the device rather than broadcasting the audio in all directions. In this way, increased privacy for the user of the personal communications device can be achieved.

Abstract: Ultrasonic transducers that are capable of generating increased levels of ultrasound, as well as receiving ultrasonic waves with increased sensitivity. The ultrasonic transducers include a back cover, a protective front cover, a backplate, and a vibrator film layer disposed between the backplate and the protective front cover. The backplate includes a plurality of grooves formed on a surface thereof facing the vibrator film layer. Each groove includes upper edges having cross-sectional contours that gradually tend toward the deepest part of the groove to allow a larger area of the backplate to be closer to the vibrator film layer, thereby increasing the resulting electric field, and, consequently, increasing the output power and sensitivity of the ultrasonic transducer.

Abstract: Ultrasonic transducers that include membrane films and perforated baseplates. An ultrasonic transducer includes a baseplate having a conductive surface with a plurality of apertures, openings, or perforations formed thereon or therethrough, and a membrane film having a conductive surface. The membrane film is positioned adjacent to the apertures, openings, or perforations formed on or through the baseplate. By applying a voltage between the conductive surface of the membrane film and the conductive surface of the baseplate, an electrical force of attraction can be created between the membrane film and the baseplate. Varying this applied voltage can cause the membrane film to undergo vibrational motion. The dimensions corresponding to the size and/or shape of the apertures, openings, or perforations formed on or through the baseplate can be varied so that different regions of the baseplate produce different frequency responses, allowing the net bandwidth of the ultrasonic transducer to be increased.

Abstract: An ultrasonic transducer including a membrane film and a perforated baseplate. The baseplate can have a conductive surface with a plurality of perforations formed through the baseplate. The membrane film can have a conductive surface and be positioned under tension proximate to the perforations formed through the baseplate. The tension of the membrane film can be controlled to provide a restoring force to counteract the moving mass of the membrane film, and the moving mass of air in the perforations of the baseplate. By selecting the diameter(s) of the perforations of the baseplate, the thickness of the baseplate, the thickness of the membrane film, the tension of the membrane film, and/or the bending stiffness of the membrane film, a wide bandpass frequency response of the ultrasonic transducer centered at an ultrasonic frequency of interest can be obtained and tailored to a desired application.

Abstract: Amplifier architecture that allows low-cost class-D audio amplifiers to be compatible with ultrasonic signals, as well as loads presented by thin-film ultrasonic transducers. The amplifier architecture replaces the traditional capacitor used as an output filter in the class-D amplifier with the natural capacitance of the ultrasonic transducer load, and employs relative impedance magnitudes to create an under-damped low-pass filter that boosts voltage in the ultrasonic frequency band of interest. The amplifier architecture includes a secondary feedback loop to ensure that correct output voltage levels are provided.

Abstract: Systems and methods of audio processing and control for improved audibility and performance in a parametric loudspeaker system. The parametric loudspeaker system includes a parametric loudspeaker providing a capacitive load, an output stage having a plurality of switches interconnected in a bridge configuration and connected to the capacitive load of the parametric loudspeaker, and a controller operative to generate a series of pulse width modulation (PWM) pulses, and to generate a plurality of control signals synchronized with the series of PWM pulses for switchingly controlling the plurality of switches in the bridge configuration, thereby driving the capacitive load of the parametric loudspeaker.

Abstract: An ultrasonic transducer including a membrane film and a perforated baseplate. The baseplate can have a conductive surface with a plurality of perforations formed through the baseplate. The membrane film can have a conductive surface and be positioned under tension proximate to the perforations formed through the baseplate. The tension of the membrane film can be controlled to provide a restoring force to counteract the moving mass of the membrane film, and the moving mass of air in the perforations of the baseplate. By selecting the diameter(s) of the perforations of the baseplate, the thickness of the baseplate, the thickness of the membrane film, the tension of the membrane film, and/or the bending stiffness of the membrane film, a wide bandpass frequency response of the ultrasonic transducer centered at an ultrasonic frequency of interest can be obtained and tailored to a desired application.

Abstract: Systems and methods of audio processing and control for improved audibility and performance in a parametric loudspeaker system. The parametric loudspeaker system includes a parametric loudspeaker providing a capacitive load, an output stage having a plurality of switches interconnected in a bridge configuration and connected to the capacitive load of the parametric loudspeaker, and a controller operative to generate a series of pulse width modulation (PWM) pulses, and to generate a plurality of control signals synchronized with the series of PWM pulses for switchingly controlling the plurality of switches in the bridge configuration, thereby driving the capacitive load of the parametric loudspeaker.

Abstract: A personal communications device that employs directional or parametric speakers to provide an enhanced user experience, delivering audio directly to a user of the device rather than broadcasting the audio in all directions. In this way, increased privacy for the user of the personal communications device can be achieved.

Abstract: Ultrasonic transducers that are capable of generating increased levels of ultrasound, as well as receiving ultrasonic waves with increased sensitivity. The ultrasonic transducers include a back cover, a protective front cover, a backplate, and a vibrator film layer disposed between the backplate and the protective front cover. The backplate includes a plurality of grooves formed on a surface thereof facing the vibrator film layer. Each groove includes upper edges having cross-sectional contours that gradually tend toward the deepest part of the groove to allow a larger area of the backplate to be closer to the vibrator film layer, thereby increasing the resulting electric field, and, consequently, increasing the output power and sensitivity of the ultrasonic transducer.

Abstract: A personal communications device that employs directional or parametric speakers to provide an enhanced user experience, delivering audio directly to a human user of the device rather than broadcasting the audio in all directions. As a result, increased privacy for the user of the personal communications device can be achieved.

Abstract: Ultrasonic transducers that include membrane films and perforated baseplates. An ultrasonic transducer includes a baseplate having a conductive surface with a plurality of apertures, openings, or perforations formed thereon or therethrough, and a membrane film having a conductive surface. The membrane film is positioned adjacent to the apertures, openings, or perforations formed on or through the baseplate. By applying a voltage between the conductive surface of the membrane film and the conductive surface of the baseplate, an electrical force of attraction can be created between the membrane film and the baseplate. Varying this applied voltage can cause the membrane film to undergo vibrational motion. The dimensions corresponding to the size and/or shape of the apertures, openings, or perforations formed on or through the baseplate can be varied so that different regions of the baseplate produce different frequency responses, allowing the net bandwidth of the ultrasonic transducer to be increased.

Abstract: Ultrasonic transducers that are capable of generating increased levels of ultrasound, as well as receiving ultrasonic waves with increased sensitivity. The ultrasonic transducers include a back cover, a protective front cover, a backplate, and a vibrator film layer disposed between the backplate and the protective front cover. The backplate includes a plurality of grooves formed on a surface thereof facing the vibrator film layer. Each groove includes upper edges having cross-sectional contours that gradually tend toward the deepest part of the groove to allow a larger area of the backplate to be closer to the vibrator film layer, thereby increasing the resulting electric field, and, consequently, increasing the output power and sensitivity of the ultrasonic transducer.

Abstract: Ultrasonic transducers that include membrane films and perforated baseplates. An ultrasonic transducer includes a baseplate having a conductive surface with a plurality of apertures, openings, or perforations formed thereon or therethrough, and a membrane film having a conductive surface. The membrane film is positioned adjacent to the apertures, openings, or perforations formed on or through the baseplate. By applying a voltage between the conductive surface of the membrane film and the conductive surface of the baseplate, an electrical force of attraction can be created between the membrane film and the baseplate. Varying this applied voltage can cause the membrane film to undergo vibrational motion. The dimensions corresponding to the size and/or shape of the apertures, openings, or perforations formed on or through the baseplate can be varied so that different regions of the baseplate produce different frequency responses, allowing the net bandwidth of the ultrasonic transducer to be increased.

Abstract: Amplifier architecture that allows low-cost class-D audio amplifiers to be compatible with ultrasonic signals, as well as loads presented by thin-film ultrasonic transducers. The amplifier architecture replaces the traditional capacitor used as an output filter in the class-D amplifier with the natural capacitance of the ultrasonic transducer load, and employs relative impedance magnitudes to create an under-damped low-pass filter that boosts voltage in the ultrasonic frequency band of interest. The amplifier architecture includes a secondary feedback loop to ensure that correct output voltage levels are provided.

Abstract: Amplifier architecture that allows low-cost class-D audio amplifiers to be compatible with ultrasonic signals, as well as loads presented by thin-film ultrasonic transducers. The amplifier architecture replaces the traditional capacitor used as an output filter in the class-D amplifier with the natural capacitance of the ultrasonic transducer load, and employs relative impedance magnitudes to create an under-damped low-pass filter that boosts voltage in the ultrasonic frequency band of interest. The amplifier architecture includes a secondary feedback loop to ensure that correct output voltage levels are provided.

Abstract: Ultrasonic transducers that include backplates with a plurality of linear physical features formed on surfaces thereof and vibrator films tensioned in a specified manner for improved transducer performance. An ultrasonic transducer includes a backplate, a vibrator film, and a compliant member. The backplate includes the plurality of linear physical features formed parallel to one another on the backplate surface. The vibrator film has a metallized side and a non-metallized side, and is positioned proximate to the backplate such that its non-metallized side faces the linear physical features on the backplate surface. The compliant member applies a spring force to the vibrator film for urging the vibrator film against the backplate surface, while maintaining a constant, consistent, and uniform tension in the vibrator film in substantially one direction, preferably perpendicular to the linear physical features along the backplate surface.

Abstract: A personal communications device that employs directional or parametric speakers to provide an enhanced user experience, delivering audio directly to a human user of the device rather than broadcasting the audio in all directions. As a result, increased privacy for the user of the personal communications device can be achieved.