An ultrasonic signal detecting circuit, an ultrasonic signal detecting method, and a display panel. The ultrasonic signal detecting circuit includes a control sub-circuit and a sensing sub-circuit. The sensing sub-circuit detects an ultrasonic echo signal, and generates a piezoelectric signal, which includes a first sub signal and a second sub-signal, according to the ultrasonic echo signal, the voltage value of one of the first and second sub-signals are higher than the value of a reference voltage signal, and that of the other one of the first and second sub-signals are lower than the reference voltage signal. The control sub-circuit is electrically connected to the sensing sub-circuit. Under control of the first sub-signal, a first power supply end and an output end of the control sub-circuit are turned on; and under control of the second sub-signal, the first power supply end and the output end of the control sub-circuit are turned on.

A wafer scale ultrasonic sensor assembly includes a wafer substrate, an ultrasonic element, first and second protective layers, conductive wires, a transmitting material, an ASIC, a conductive bump, and a soldering portion. The wafer substrate includes a via. The ultrasonic element is exposed to the via. The conductive wires are on the first protective layer and connected to the ultrasonic element. The second protective layer covers the conductive wires, and the second protective layer has an opening corresponding to the ultrasonic element. The transmitting material contacts the ultrasonic element. The ASIC is connected to the wafer substrate, so that the via forms a space between the ASIC and the ultrasonic element. The conductive pillar is in a via defined through the ASIC, the wafer substrate, and the first protective layer, and the conducive pillar is respectively connected to the conductive wires and the soldering portion.

A display device, a method for producing a display device, and a gesture recognition method are disclosed. The display device includes a display module including a base and an array substrate, a resin layer, a first electrode layer, a pixel definition layer, a light-emitting unit layer, a second electrode layer disposed opposite to the first electrode layer, and an encapsulation layer. The light-emitting unit layer is between the first electrode layer and the second electrode layer and includes a plurality of light-emitting units respectively in a plurality of openings of the pixel definition layer, and an ultrasonic sensor including the second electrode layer, a piezoelectric material layer between the first electrode layer and the pixel definition layer, and a third electrode layer between the pixel definition layer and the resin layer. The piezoelectric material layer includes a plurality of piezoelectric material units separated by the plurality of light-emitting units.

An acoustophoretic system is controlled and driven to attain a desired level of performance. An RF controller and a driver provide a frequency and power to an acoustic transducer, which can be implemented as a piezoelectric element, which presents a reactive load or a complex load. A controller implements a control technique for efficient transducer operation. The control technique can locate a frequency for operation that is at a reactance minimum or maximum for the system to produce a modal pattern and to provide efficient operation of the transducer. A method of detecting a minimum or maximum reactance in a acoustophoretic system used to trap, separate, deflect, cluster, fractionate or otherwise process particles or secondary fluids or tertiary fluids in a primary fluid and utilizing the frequency of the detected reactance to operate the acoustophoretic system.

A vibration actuator and a method for driving the vibration actuator can improve the user's tactile sensation. A plurality of tactile devices are attachable at different positions on a surface of a touch panel to vibrate the touch panel. A driver drives, in response to a touch detection signal representing a touch position from the touch panel, the plurality of tactile devices each using a driving signal having a predetermined driving frequency. Of the plurality of tactile devices, a tactile device closest to the touch position is operable as a master device, and a tactile device other than the master device is operable as a slave device. The master device and the slave device are driven using the driving signal having the driving frequency being a resonant frequency of the master device.

A system for removing debris from a vision-based sensor of an agricultural machine includes an agricultural machine and a vision-based sensor supported on the agricultural machine. The vision-based sensor is configured to generate vision data. The system further includes a vibration source configured to be a separate component frons the vision-based sensor. The vibration source is supported on the agricultural machine. Moreover, the vibration source is configured to oscillate the vision-based sensor to remove debris from the vision-based sensor.

Disclosed are various techniques operating a linear resonant actuator (LRA). In some aspects, a method for operating an LRA includes generating an LRA control signal having a period, the period having an active portion and a high-Z portion according to a duty cycle; detecting, during the high-Z portion of the period, a back electromotive force (BEMF) threshold voltage crossing time and zero voltage crossing time; calculating a period; calculating a BEMF measurement window; calculating a target duty cycle based on the period, the BEMF measurement window, and a margin time; and adjusting the duty cycle of the LRA control signal towards the target duty cycle.

Aspects of the technology described herein relate to sensing a fingerprint of a subject via an ultrasound fingerprint sensor. Certain aspects relate to transmitting and receiving ultrasound data at multiple different frequencies to provide sensing data from different depths within the skin of the subject. Since different ultrasound frequencies are expected to penetrate a subject's skin to different degrees, sensing a finger at multiple ultrasound frequencies may provide information on different physical aspects of the finger. For instance, sound ultrasound frequencies may sense a surface of the skin, whereas other ultrasound frequencies may penetrate through one or more of the epidermal, dermal or subcutaneous layers. The ultrasound fingerprint apparatus may have utility in various applications, including but not limited to mobile electronic devices, such as mobile phones or tablet computers, a laptop computer or biometric access equipment.

Disclosed are various techniques operating a linear resonant actuator (LRA). In some aspects, a method for operating an LRA includes generating an LRA control signal having a period, the period having an active portion and a high-Z portion according to a duty cycle; detecting, during the high-Z portion of the period, a back electromotive force (BEMF) threshold voltage crossing time and zero voltage crossing time; calculating a period; calculating a BEMF measurement window; calculating a target duty cycle based on the period, the BEMF measurement window, and a margin time; and adjusting the duty cycle of the LRA control signal towards the target duty cycle.

An ultrasonic-based system includes a transmitter and receiver, an ultrasonic transducer including ≥1 piezoelectric element having a matching layer thereon connected to the transmitter. A controller is coupled to the transmitter. The transmitter is for driving the piezoelectric element with a pulsed electrical signal, where the piezoelectric element transmits a transmit ultrasonic signal. A current/voltage measurement circuit is coupled to sense a current or voltage in the transmitter. The controller is for implementing an algorithm for an ultrasonic transducer monitoring method including comparing an amplitude of the pulsed signal to a predetermined limit. When the pulsed signal is determined to be outside the limit, an impedance of the piezoelectric element is determined to be abnormal. When the pulsed signal is within the limit, the amplitude of the received signal is compared to a lower limit, which when below results in determining a cleaning operation for the ultrasonic transducer is needed.