CMUT Ultrasonic Sensor Segmented Electrode Voltage Control
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Solution Overview
Problem
Existing ultrasonic sensors with capacitive micromachined ultrasonic transducers (CMUTs) face challenges in generating sufficient membrane vibration for both transmission and receive modes due to the simultaneous application of DC and AC voltages, leading to image distortion and reduced measurement accuracy.
Innovation Solution
The ultrasonic sensor employs a plurality of first and second CMUTs arranged in a cross configuration, with separate electrodes for receiving reference voltages, DC voltages, and AC voltages. This configuration allows for independent control of DC and AC voltages through transistors, enabling precise timing and reduced image distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If both DC voltage and AC voltage are applied to the same electrode on the membrane, then the membrane vibration is generated, but the DC and AC voltages cannot be controlled separately leading to insufficient membrane vibration amplitude
Solution Approach 1:
The patent divides the electrode structure into multiple independent electrodes: a first electrode for receiving DC voltage, a second electrode for receiving AC voltage, and a third electrode for receiving reference voltage. This segmentation allows independent control of DC and AC voltages, enabling separate optimization of membrane vibration amplitude and signal detection without mutual interference.
2Measurement precision
If DC voltage is applied to the electrode on the membrane in receive mode, then the membrane generates sufficient vibration, but the switching time causes serious distortion of the CMUT image
Solution Approach 1:
The patent separates the DC voltage application electrode from the AC voltage output electrode. In receive mode, the first electrode receives DC voltage to maintain membrane vibration, while the second electrode outputs the AC voltage signal. This separation eliminates switching time delays between DC voltage application and AC voltage output, preventing image distortion.
Solution Approach 2:
The DC voltage is applied to the first electrode in advance to establish the membrane's vibration capability before the AC voltage signal is output through the second electrode. This preliminary action ensures the membrane is ready for immediate response, eliminating switching delays.
3Ease of operation
If only AC voltage is applied to the electrode on the membrane, then the electrode outputs AC voltage, but the membrane vibration is not large enough
Solution Approach 1:
The patent divides the voltage application function into two separate electrodes: the first electrode for DC voltage application to establish membrane vibration, and the second electrode for AC voltage application to generate sufficient vibration amplitude. This segmentation allows both voltages to be applied simultaneously but independently, achieving both operational simplicity and sufficient vibration amplitude.
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 solution allows for accurate generation and reception of ultrasonic waves, improving signal-to-noise ratio and maintaining imaging quality by enabling precise control over voltage applications, thus addressing the limitations of existing CMUT technologies.
Implementation Method 1
A capacitive micromachined ultrasonic transducer (CMUT) is a type of ultrasonic transducer that uses the principle of capacitance to generate and detect ultrasound waves
Implementation Method 2
The DC voltage causes the membrane to deflect towards the ground electrode
Implementation Method 3
The distance between the membrane and the ground electrode changes due to the ultrasound waves, which causes a corresponding change in the capacitance between the membrane and the ground electrode
Data Source
AI summary
An ultrasonic sensor includes M rows of first capacitance micromachined ultrasonic transducers (CMUTs) and N columns of second CMUTs, where M and N are both greater than 1. Each first CMUT has a plurality of first electrodes, a second electrode, and a third electrode for receiving a reference voltage, a first direct current voltage, and a first alternating current voltage, respectively. A first cavity is formed between each first electrode and the second electrode. Each second CMUT has a plurality of fourth electrodes, a fifth electrode, and a sixth electrode for receiving the reference voltage, receiving a second direct current voltage, and generating a second alternating current voltage, respectively. A second cavity is formed between each fourth electrode and the fifth electrode.