Abstract: A device comprises a processor coupled with an ultrasonic transducer coupled which is configured to emit an ultrasonic pulse and receive returned signals received after a ringdown period of the transducer and corresponding to the emitted ultrasonic pulse. The processor is configured to evaluate the returned signals to find a candidate echo, from an object located in a ringdown blind spot area, in a time window between one and two times the ringdown period; locate multiple echoes from the object of higher order than the candidate echo; validate the candidate echo as at least a secondary echo associated of the object; and determine, based on analysis of the returned signals, an estimated distance from the transducer to the object in the ringdown blind spot area, wherein the ringdown blind spot area is located between the transducer and a closest distance at which objects can be sensed by the transducer.

Abstract: A piezoelectric micromachined ultrasound transducer (PMUT) is disclosed. The device consists of a flexible membrane that is connected to a rigid substrate via flexures. The flexures are defined by slots etched through the perimeter of the membrane. These features release the stress present on the structural layers of the membrane, making it less sensitive to residual stress. The flexures are designed to act as torsion springs so that the membrane's vibration mode shape is highly curved in the piezoelectric actuation area, thereby increasing the electromechanical coupling.

Abstract: A device comprises a processor coupled with an ultrasonic transducer which is configured to emit an ultrasonic pulse and receive corresponding returned signals associated with a distance range of interest in a field of view of the ultrasonic transducer. The processor is configured to: remove a low frequency component from the returned signals to achieve modified returned signals; calculate, from the modified returned signals, a variation in amplitude; determine a quantification of the variation in amplitude for a first subset of the modified returned signals associated with a first subrange of the distance range of interest; employ the quantification to correct for changes in the first subset to achieve first normalized sensor data for the first subrange, where the first normalized sensor data is sensitive to occurrence of change over time in the first subrange; and detect a moving object in the first subrange using the first normalized sensor data.

Abstract: A device comprises a processor coupled with an ultrasonic transducer coupled which is configured to emit an ultrasonic pulse and receive returned signals received after a ringdown period of the transducer and corresponding to the emitted ultrasonic pulse. The processor is configured to evaluate the returned signals to find a candidate echo, from an object located in a ringdown blind spot area, in a time window between one and two times the ringdown period; locate multiple echoes from the object of higher order than the candidate echo; validate the candidate echo as at least a secondary echo associated of the object; and determine, based on analysis of the returned signals, an estimated distance from the transducer to the object in the ringdown blind spot area, wherein the ringdown blind spot area is located between the transducer and a closest distance at which objects can be sensed by the transducer.

Abstract: A robotic cleaning appliance includes a housing, surface treatment item, surface type detection sensor, and processor. The sensor emits sonic signals toward a surface being traversed and receives corresponding returned signals from the surface. The returned signals are used for surface type detection and include directly reflected primary returned signals and multi-path reflected secondary returned signals which return at a later time than the primary returned signals. The processor selects a window of time after transmission of a sonic signal such that the returned signals in the window comprise at least a portion of the secondary returned signals, wherein the window is related to round trip time-of-flight of the returned signals; processes the returned signals falling in the window to achieve a reflectivity metric; compares the reflectivity metric to a stored value; and based on the comparison, determines which surface type of a plurality of surface types has been detected.

Abstract: An apparatus comprises an ultrasonic transducer having a first and second electrode and switches which configured to selectively connect the first and second electrodes to a transmit voltage source or to a receive amplifier. The switches are configured to selectively connect a first input of the amplifier to the first electrode of the transducer and to selectively connect a second input of the amplifier to the second electrode of the transducer. The switches are also configured to selectively connect the voltage source to the first and second electrodes of the transducer. The transducer may include a piezoelectric layer attached to and sandwiched between the first electrode and the second electrode, and a flexible membrane attached to the first electrode. The piezoelectric layer may be patterned to form an annular ring at the outer diameter of the flexible membrane.

Abstract: An ultrasonic input includes two or more ultrasonic transceiver units having transducers separated from each other by a predetermined spacing and a processor coupled to the transceiver units. In some implementations one unit transmits while two receive and in other implementations one unit transmits and receives while the other just receives. The transmitter sends an ultrasonic pulse and first and second receivers receive echoes of the ultrasonic pulse from an object. The processor and/or transceiver units use first and second receive signals to determine first and second time-of-flight (ToF) measurements corresponding to times between transmitting an ultrasonic pulse and receiving an echo of the ultrasonic pulse.

Abstract: A piezoelectric micromachined ultrasound transducer (PMUT) is disclosed. The device consists of a flexible membrane that is connected to a rigid substrate via flexures. The flexures are defined by slots etched through the perimeter of the membrane. These features release the stress present on the structural layers of the membrane, making it less sensitive to residual stress. The flexures are designed to act as torsion springs so that the membrane's vibration mode shape is highly curved in the piezoelectric actuation area, thereby increasing the electromechanical coupling.

Abstract: A package design for a micromachined ultrasound transducer (MUT) utilizing curved geometry to control the presence and frequency of acoustic resonant modes is described. The approach consists of reducing in number and curving the reflecting surfaces present in the package cavity to adjust the acoustic resonant frequencies to locations outside the band of interest. The design includes a cavity characterized by a curved geometry and a MUT mounted to a side of a substrate facing the cavity with a sound emitting portion of the MUT facing an opening in the substrate. The substrate is disposed over an opening of the cavity with the substrate oriented such that the MUT located within the cavity.

Abstract: An ultrasonic transmitter system includes a digital controller, bandpass pulse-width modulator (BP-PWM) unit, a digital to analog converter (DAC), and an ultrasound transducer. The controller generates pulse width and phase reference signals. The BP-PWM configured receives these signals generates a pulse width modulation (PWM) output characterized by a pulse width and a phase based on the pulse width and phase reference signals. The DAC) receives the PWM output from the BP-PWM unit and generates an output characterized by the pulse width and phase. The ultrasonic transducer receives the output from the DAC and generates an output sound pressure in response to the output from the DAC. An amplitude of the RMS sound pressure depends on the pulse width of the output from the DAC.

Abstract: An ultrasound transducer may be driven by a driver circuit having one or more charge pumps and a multi-level inverter. The one or more charge pumps are configured to drive the ultrasound transducer only during output transitions of the inverter.

Abstract: A miniature rangefinder includes a housing, a micromachined ultrasonic transducer, and signal processing circuitry. The housing includes a substrate and a lid. The housing has one or more apertures and the micromachined ultrasonic transducer is mounted over an aperture. The micromachined ultrasonic transducer may function as both a transmitter and a receiver. An integrated circuit is configured to drive the transducer to transmit an acoustic signal, detect a return signal, and determine a time of flight between emitting the acoustic signal and detecting the return signal.

Abstract: A miniature rangefinder includes a housing, a micromachined ultrasonic transducer, and signal processing circuitry. The housing includes a substrate and a lid. The housing has one or more apertures and the micromachined ultrasonic transducer is mounted over an aperture. The micromachined ultrasonic transducer may function as both a transmitter and a receiver. An integrated circuit is configured to drive the transducer to transmit an acoustic signal, detect a return signal, and determine a time of flight between emitting the acoustic signal and detecting the return signal.

Abstract: A piezoelectric micromachined ultrasound transducer (PMUT) is disclosed. The PMUT consists of a flexural membrane that is piezoelectrically actuated. These membranes are formed on a first substrate that is bonded to a second substrate. The two substrates are separated by an air gap to allow the PMUT to vibrate. Several methods for joining the two substrates are described.