A circuit for generating and detecting ultrasonic sensing signals is provided. A piezoelectric device having a transmitting electrode and a receiving electrode is coupled to a biasing-and-sampling sub-circuit configured to set different bias voltages to the receiving electrode. The piezoelectric device is configured to transmit an ultrasonic signal upon applying an exciting pulse signal to the transmitting electrode and alternatively to generate a voltage signal at the receiving electrode upon receiving an echo signal based on the ultrasonic signal. A signal-collecting sub-circuit is coupled to the receiving electrode to determine a first sampling voltage based on the voltage signal at the receiving electrode in a first sampling period and a second sampling voltage based on the voltage signal at the receiving electrode in a second sampling period. An output sub-circuit is coupled to the signal-collecting sub-circuit for outputting the first sampling voltage and the second sampling voltage at a same time.

A circuit for generating and detecting ultrasonic sensing signals is provided. A piezoelectric device having a transmitting electrode and a receiving electrode is coupled to a biasing-and-sampling sub-circuit configured to set different bias voltages to the receiving electrode. The piezoelectric device is configured to transmit an ultrasonic signal upon applying an exciting pulse signal to the transmitting electrode and alternatively to generate a voltage signal at the receiving electrode upon receiving an echo signal based on the ultrasonic signal. A signal-collecting sub-circuit is coupled to the receiving electrode to determine a first sampling voltage based on the voltage signal at the receiving electrode in a first sampling period and a second sampling voltage based on the voltage signal at the receiving electrode in a second sampling period. An output sub-circuit is coupled to the signal-collecting sub-circuit for outputting the first sampling voltage and the second sampling voltage at a same time.

Disclosed are a piezoelectric speaker employing a piezoelectric device having a through-hole and a method for manufacturing the same. The piezoelectric speaker includes a piezoelectric device including a stacked body having through-holes and electrodes formed at the stacked body, an adhesive layer disposed on the lower surface of the piezoelectric device, and a diaphragm attached to the piezoelectric device by the adhesive layer. The through-holes are arranged to decrease in size as they move away from the center of the piezoelectric element. The through-holes have a symmetrical arrangement with respect to the center, and the inner surface of each through-hole has a curved edge. The structure and arrangement of these through-holes do not cause cracks during the sintering process.

Disclosed are a piezoelectric speaker employing a piezoelectric device having a through-hole and a method for manufacturing the same. The piezoelectric speaker includes a piezoelectric device including a stacked body having through-holes and electrodes formed at the stacked body, an adhesive layer disposed on the lower surface of the piezoelectric device, and a diaphragm attached to the piezoelectric device by the adhesive layer. The through-holes are arranged to decrease in size as they move away from the center of the piezoelectric element. The through-holes have a symmetrical arrangement with respect to the center, and the inner surface of each through-hole has a curved edge. The structure and arrangement of these through-holes do not cause cracks during the sintering process.

The present disclosure relates to a display apparatus, especially having a display panel generating sounds. A display apparatus according to the present disclosure includes: a display module; a back cover at a rear surface of the display module; a depression recessed into the back cover from a first surface of the back cover with a first width and a first depth; a penetration through from a second surface of the back cover to the depression with a second width smaller than the first width and a second depth corresponding to a difference between a thickness of the back cover and the first depth; and a first piezo vibration unit disposed at a stepped portion between the penetration and the depression.

The present disclosure relates to a display apparatus, especially having a display panel generating sounds. A display apparatus according to the present disclosure includes: a display module; a back cover at a rear surface of the display module; a depression recessed into the back cover from a first surface of the back cover with a first width and a first depth; a penetration through from a second surface of the back cover to the depression with a second width smaller than the first width and a second depth corresponding to a difference between a thickness of the back cover and the first depth; and a first piezo vibration unit disposed at a stepped portion between the penetration and the depression.

The present disclosure relates to a flexible vibration film and a display apparatus having the same. A flexible vibration film includes: a vibration layer; a first electrode layer disposed on a bottom surface of the vibration layer; and a second electrode layer disposed on a top surface of the vibration layer, wherein the vibration layer includes: a first vibration unit having a first vibration characteristics; a second vibration unit having a second vibration characteristics; and a flexible insulating part disposed between the first vibration unit and the second vibration unit, and wherein the first electrode layer includes: a first part corresponding to the first vibration unit; and a second part corresponding to the second vibration unit.

The present disclosure relates to a flexible vibration film and a display apparatus having the same. A flexible vibration film includes: a vibration layer; a first electrode layer disposed on a bottom surface of the vibration layer; and a second electrode layer disposed on a top surface of the vibration layer, wherein the vibration layer includes: a first vibration unit having a first vibration characteristics; a second vibration unit having a second vibration characteristics; and a flexible insulating part disposed between the first vibration unit and the second vibration unit, and wherein the first electrode layer includes: a first part corresponding to the first vibration unit; and a second part corresponding to the second vibration unit.

A piezoelectric vibration plate includes a base that includes a central portion and a circumferential portion and has conductivity. A piezoelectric portion is provided on the central portion that performs bending vibration in a manner to reciprocate between both sides in a thickness direction of the base when a voltage is applied to the piezoelectric portion. The base includes at least one penetration portion positioned between the central portion and the circumferential portion, and at least one coupling portion that couples the central portion to the circumferential portion. The at least one coupling portion is arranged on a farthest position from a center, at which maximum displacement is generated in the bending vibration, of the central portion.

A display apparatus includes a display panel configured to display an image, and a vibration device on a rear surface of the display panel to vibrate the display panel to generate a sound, the vibration device including a vibration array including a plurality of vibration modules.