cMUT Array Pitch Mismatch for Modular Tiling
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Solution Overview
Problem
Existing ultrasound transducer arrays face challenges in scalability and modular design due to limitations in ASIC design flexibility and the need for seamless tiling of transducer modules, which can result in image artifacts and high costs associated with ASIC redesign for varying transducer designs.
Innovation Solution
The solution involves a control circuit with an array of circuit portions and capacitive micromachined ultrasound transducer elements, where the pitch of the transducer elements is greater than the circuit portions in at least one direction, allowing for overlap and enabling modular design and seamless tiling while maintaining a regular array of transducer elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pitch of cMUT elements is made greater than the pitch of circuit portions, then modular design and seamless tiling are enabled, but the regularity of the array is compromised
Solution Approach 1:
The transducer array is divided into modular units, each comprising a subset of cMUT elements and their corresponding circuit portions. These modules can be independently designed, manufactured, and then tiled together to form larger arrays, enabling flexibility while maintaining regularity through standardized module interfaces
Solution Approach 2:
The patent implements a hierarchical structure where circuit portions are nested beneath the cMUT element array. The circuit portions occupy a smaller area than the cMUT elements, creating an overlapping region that allows modules to be tiled together while maintaining both design flexibility and array regularity
2Reliability
If ASIC redesign is performed for varying transducer designs, then optimal performance is achieved, but cost and time consumption increase significantly
Solution Approach 1:
The control circuit is designed with universal circuit portions that can interface with multiple different cMUT element configurations. The pitch-mismatched design allows the same control circuit to support varying transducer designs (different frequencies, apertures) without requiring ASIC redesign, achieving multi-functionality
Solution Approach 2:
The patent enables transducer design variations through parameter changes in the cMUT elements (such as element size, spacing, and material properties) while keeping the control circuit parameters fixed. The pitch mismatch provides the necessary design space to vary transducer parameters without affecting the control circuit
3Area of stationary object
If transducer arrays are tiled to exceed reticle area, then larger aperture is achieved, but gaps between modules cause image artifacts
Solution Approach 1:
The circuit portions are pre-positioned beneath the cMUT elements during the same fabrication process, ensuring precise alignment before tiling. The overlapping geometry of circuit portions relative to cMUT elements creates inherent alignment features that simplify the tiling process and reduce gaps between modules
Solution Approach 2:
The circuit portions serve as an intermediary layer that mediates between the cMUT element array and the substrate. This intermediate structure provides a stable platform for tiling, with the pitch mismatch creating overlap regions that act as buffers to minimize the impact of alignment tolerances on final image quality
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 approach allows for the creation of larger transducer arrays with improved image quality and reduced costs by enabling the reuse of ASIC designs for different transducer designs, simplifying the dicing process, and reducing the complexity of ASIC redesign.
Implementation Method 1
capacitive micromachined ultrasound transducer, cMUT, elements
Data Source
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AI summary
An ultrasound transducer has a control circuit with an array of circuit portions which together define a circuit area. cMUT elements are provided over the top of the control circuit. Vias provide a coupling between each cMUT element and a respective one of the circuit portions beneath. The vias are located at spaces between the cMUT elements and connect to the circuit portion beneath at a position relative to the shape of the circuit portion. The pitch of the array is greater than the pitch of the circuit portions in at least one direction of the array such that in said at least one direction, the cMUT elements extend beyond one or both sides of the circuit area. This makes tiling easier and enables a modular design.