CMUT Nanoposts for High Sensitivity and Multi-Frequency Operation
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Solution Overview
Problem
Existing capacitive micromachined ultrasonic transducers (CMUTs) face challenges in achieving high transmission and reception sensitivity due to limited average displacement caused by small gap height between electrodes and limited voltage, as well as the need for multi-frequency operation to increase applicability.
Innovation Solution
The proposed CMUT design includes a substrate, a top electrode, a supporter made of insulating material, and a plurality of nanoposts with varying diameters and densities. These nanoposts are compressible and stretchable, allowing for increased average displacement and multi-frequency operation by adjusting the structure and shape of the top plate reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gap height between electrodes is increased to increase average displacement, then transmission and reception sensitivity is improved, but high voltage application is required which is not desirable
Solution Approach 1:
The patent changes the physical parameters of the nanoposts including their diameter (ranging from 10nm to 100nm), length, and material composition to optimize the gap height and displacement characteristics. By adjusting these parameters, the system achieves high sensitivity without requiring high voltage operation
Solution Approach 2:
The nanoposts are constructed from composite materials with specific mechanical and electrical properties. The use of materials with controlled elasticity and piezoelectric characteristics enables the nanoposts to achieve large displacements at low voltages, resolving the contradiction between sensitivity and voltage requirement
2Ease of manufacture
If edges of moving cells are all fixed to simplify structure, then manufacturing is easier, but average displacement is small due to large displacements only at center portion and small displacements at edge portion
Solution Approach 1:
The patent segments the moving cell structure by dividing it into multiple independent nanoposts instead of a continuous fixed structure. Each nanopost can displace independently, and their collective motion creates a uniform average displacement across the entire electrode surface, solving the problem of low average displacement while maintaining manufacturing simplicity
Solution Approach 2:
The nanoposts are distributed non-uniformly across the electrode surface with varying densities and orientations. This local variation in structure allows different regions to contribute optimally to the overall displacement, achieving high average displacement without complex edge fixation
3Device complexity
If single frequency operation is used to simplify design, then device complexity is reduced, but applicability is limited
Solution Approach 1:
The nanopost structure is designed with inherent multi-frequency resonant characteristics. By adjusting the excitation frequency, the same device can operate at multiple frequencies, providing universal applicability across different medical imaging and sensing applications without increasing device complexity
Solution Approach 2:
The system utilizes the dynamic resonant properties of the nanoposts, which can be excited at multiple frequencies. The structure's natural frequencies are engineered to provide optimal performance across a broad frequency range, enabling multi-frequency operation through dynamic response rather than static design
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
The enhanced CMUT design significantly increases transmission and reception sensitivity by maximizing average displacement and enables multi-frequency operation, allowing for broader applicability in medical imaging and other fields.
Implementation Method 1
a plurality of nanoposts having both ends coupled and fixed to the substrate and the top electrode in the gap, and being compressible and stretchable in a longitudinal direction to at least vertically move the top electrode when power is applied to the top electrode
Implementation Method 2
The plurality of monocrystalline materials may at least include a piezoelectric material capable of vibrating when an electrical signal is received
Implementation Method 3
capacitive micromachined ultrasonic transducer (CMUT) capable of increasing an operating frequency range and a transducer bandwidth and of achieving integration through a semiconductor process
Data Source
AI summary
Provided is a capacitive micromachined ultrasonic transducer (CMUT) including a substrate, a top electrode provided on the substrate to be spaced apart from the substrate, a supporter made of an insulating material and coupled between the substrate and an edge of the top electrode to support and fix the edge of the top electrode and to define a gap between the substrate and the edge of the top electrode, and a plurality of nanoposts having both ends coupled and fixed to the substrate and the top electrode in the gap, and being compressible and stretchable in a longitudinal direction to at least vertically move the top electrode when power is applied to the top electrode.