CMUT Dielectric Gradient Reduces Pull-in Voltage
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Solution Overview
Problem
Capacitive Micro-machined Ultrasonic Transducers (CMUT) require high pull-in operating voltages to enhance sensitivity and acoustic intensity, but achieving these voltages is challenging, leading to reliability and safety issues, especially when used in medical applications where high voltages can be hazardous.
Innovation Solution
The acoustic transduction unit incorporates a dielectric pattern at the bottom and top of the vibrating cavity with gradually increasing thickness, reducing the pull-in operating voltage while increasing capacitance and sensitivity, by ensuring the vibrating diaphragm can reach effective travel without compromising structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high pull-in operating voltage is applied to enhance sensitivity and acoustic intensity, then detection sensitivity and acoustic intensity are improved, but reliability and safety deteriorate due to hazardous high voltages
Solution Approach 1:
The patent changes the physical parameters of the vibrating cavity by introducing dielectric patterns with gradually increasing thickness from center to edge. This geometric parameter modification alters the electric field distribution and capacitance characteristics, enabling the system to achieve high sensitivity and acoustic intensity at reduced operating voltages, thus resolving the contradiction between performance and safety
Solution Approach 2:
The dielectric patterns are applied locally at specific positions within the vibrating cavity rather than uniformly throughout. The gradual thickness variation creates localized electric field enhancement at the center while maintaining safety margins at the edges, allowing high sensitivity in the detection region without compromising overall reliability
2Power
If high pull-in operating voltage is applied to enhance acoustic intensity, then intensity of transmitted ultrasonic waves is improved, but reliability and safety deteriorate
Solution Approach 1:
By modifying the geometric parameters of the vibrating cavity through dielectric patterns with gradient thickness, the patent optimizes the capacitance and electric field distribution. This enables high acoustic intensity output at lower operating voltages, resolving the contradiction between power output and safety
3Reliability
If dielectric pattern with gradually increasing thickness is introduced, then pull-in operating voltage is reduced and capacitance is increased, but device complexity increases
Solution Approach 1:
The dielectric patterns are implemented as localized structures within the vibrating cavity rather than requiring complete structural redesign. The gradual thickness variation is achieved through controlled deposition or etching processes that add functional complexity only where needed, minimizing overall device complexity while achieving the voltage reduction goal
Solution Approach 2:
The dielectric patterns act as intermediary elements between the electrodes and the vibrating diaphragm. These intermediate structures modify the electric field distribution and capacitance characteristics without requiring fundamental changes to the basic CMUT structure, thus reducing operating voltage while limiting complexity increase
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 design reduces the required pull-in operating voltage, enhances the intensity of transmitted ultrasonic waves, and improves detection sensitivity, while maintaining safety by minimizing the risk associated with high voltages.
Implementation Method 1
reducing the pull-in operating voltage while increasing capacitance and sensitivity
Implementation Method 2
Capacitive Micro-machined Ultrasonic Transducer (CMUT)
Implementation Method 3
the vibrating diaphragm pattern is on a side of the support pattern distal to the first electrode, and is configured to vibrate in the vibrating cavity
Data Source
AI summary
An acoustic transduction unit is provided including: a first electrode on a base substrate, a support pattern on a side of the first electrode distal to the base substrate, a vibrating diaphragm pattern surrounded by the support pattern, the first electrode and the vibrating diaphragm pattern and on a side of the support pattern distal to the first electrode; and a second electrode on a side of the vibrating diaphragm pattern distal to the first electrode and opposite to the first electrode; and a first dielectric pattern at the bottom of the vibrating cavity; wherein a thickness of the first dielectric pattern gradually increases from a first vertex to an edge of the first dielectric pattern; and/or, a second dielectric pattern at the top of the vibrating cavity; wherein a thickness of the second dielectric pattern gradually increases from a second vertex to an edge of the second dielectric pattern.