Three-Port Piezoelectric Ultrasonic Transducer for Simultaneous Signal Transmission and Reception
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Solution Overview
Problem
Existing piezoelectric ultrasonic transducers face inefficiencies in simultaneous transmission and reception of ultrasonic signals due to the need for time separation between transmit and receive modes, leading to overlapping signal overlap and reduced signal strength, especially in applications like fingerprint sensing and imaging.
Innovation Solution
A three-port piezoelectric micromechanical ultrasonic transducer (PMUT) configuration with separate electrodes for transmission and reception, allowing independent timing and enabling simultaneous signal transmission and reception, along with a reference electrode for improved mechanical stress distribution and reduced parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If time separation between transmit and receive modes is used, then device complexity is reduced, but signal strength and efficiency deteriorate due to overlapping signals
Solution Approach 1:
The patent segments the electrode functions by providing separate transmit and receive electrodes, allowing simultaneous transmission and reception operations. This segmentation resolves the contradiction by enabling independent timing control of transmit and receive signals, eliminating signal overlap while maintaining operational efficiency.
Solution Approach 2:
The patent transitions from temporal separation (time-division) to spatial separation by introducing distinct electrode structures for transmit and receive functions. This dimensional change from time-based to space-based separation allows simultaneous operations without signal interference.
2Reliability
If separate transmit and receive electrodes are used, then signal strength and efficiency are improved, but device complexity increases
Solution Approach 1:
The patent implements multi-functionality by configuring the transducer array where elements can serve as either transmit or receive elements depending on operational mode. This universal design allows the system to achieve enhanced signal strength through dedicated electrodes while managing complexity through flexible role assignment.
Solution Approach 2:
The patent merges the transmit and receive functionality within a unified transducer array structure. By combining both functions in a single integrated system rather than separate devices, the patent achieves improved signal strength through dedicated electrodes while avoiding the complexity of completely separate transmit and receive systems.
3Productivity
If simultaneous transmission and reception is enabled, then productivity is improved, but signal overlap and crosstalk increase
Solution Approach 1:
The patent segments the electrode functions by providing separate transmit and receive electrodes, allowing simultaneous transmission and reception operations. This segmentation resolves the contradiction by enabling independent timing control of transmit and receive signals, eliminating signal overlap while maintaining operational efficiency.
4Object-generated harmful factors
If time separation between transmit and receive modes is used, then crosstalk is reduced, but loss of time increases
Solution Approach 1:
The patent segments the electrode functions by providing separate transmit and receive electrodes, allowing simultaneous transmission and reception operations. This segmentation resolves the contradiction by enabling independent timing control of transmit and receive signals, eliminating signal overlap while maintaining operational efficiency.
Solution Approach 2:
The patent employs periodic signaling patterns where transmit and receive operations are coordinated in time-diverse sequences. By using periodic action with properly timed intervals, the system achieves simultaneous operational capability while preventing signal overlap through rhythmic coordination of transmit and receive cycles.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the efficiency and resolution of ultrasonic signal processing, allowing for simultaneous transmission and reception, improved signal strength, and reduced crosstalk, enabling effective imaging and fingerprint detection.
Implementation Method 1
the piezoelectric layer stack may include a layer of piezoelectric material... the piezoelectric layer stack and mechanical layer may be caused to vibrate in response to a time-varying excitation voltage
Implementation Method 2
The piezoelectric layer stack may likewise receive reflected ultrasonic pressure waves from an object in the propagation medium, and convert the received ultrasonic pressure waves into electrical signals
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3
AI summary
A piezoelectric micromechanical ultrasonic transducer (PMUT) includes a diaphragm disposed over a cavity, the diaphragm including a piezoelectric layer stack including a piezoelectric layer, a first electrode electrically coupled with transceiver circuitry, and a second electrode electrically coupled with the transceiver circuitry. The first electrode may be disposed in a first portion of the diaphragm, and the second electrode may be disposed in a second, separate, portion of the diaphragm. Each of the first and the second electrode is disposed on or proximate to a first surface of the piezoelectric layer, the first surface being opposite from the cavity. The PMUT is configured to transmit first ultrasonic signals by way of the first electrode during a first time period and to receive second ultrasonic signals by way of the second electrode during a second time period, the first time period and the second time period being at least partially overlapping.