Segmented Biasing for CMUT Manufacturing Variations
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Solution Overview
Problem
Existing ultrasound devices with capacitive micromachined ultrasonic transducers (CMUTs) face challenges in uniformly biasing membranes due to manufacturing variations, leading to non-uniform operating characteristics across the device, which affects their sensitivity and performance in both transmit and receive modes.
Innovation Solution
Implementing a segmented biasing scheme where distinct biasing segments are created for groups of CMUTs, allowing each group to receive different bias signals, and using voltage sources and detection circuits to determine and adjust the bias values for optimal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single common bias signal is applied to all CMUTs, then the device structure is simple, but manufacturing variations cause non-uniform operating characteristics across different CMUT groups
Solution Approach 1:
The patent divides the common bias electrode into multiple segmented bias electrodes, where each segment corresponds to a specific group of CMUTs. This segmentation allows independent bias voltage application to different CMUT groups, compensating for manufacturing variations while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent implements local quality by allowing different bias voltages to be applied to different spatial regions (groups) of CMUTs. Each bias electrode segment provides locally optimized biasing tailored to the specific manufacturing characteristics of its corresponding CMUT group, improving overall device uniformity.
2Reliability
If distinct bias signals are applied to different CMUT groups, then sensitivity and performance consistency are improved, but the device complexity increases
Solution Approach 1:
The biasing system is segmented into multiple independent bias electrode groups, each controllable by separate voltage sources. This segmentation enables performance optimization for different CMUT groups while keeping each segment relatively simple in design.
Solution Approach 2:
The segmented bias electrode structure serves multiple functions: it provides independent bias control for different CMUT groups, compensates for manufacturing variations, and maintains a structure that is still compatible with standard CMUT fabrication processes.
3Device complexity
If fixed bias voltages are used for all CMUTs, then the control system is simple, but dynamic adjustment for optimal operation is not achieved
Solution Approach 1:
The patent transitions from fixed bias voltages to dynamically adjustable bias voltages for each CMUT group. The detection circuits monitor operating characteristics and enable real-time adjustment of bias signals, allowing the system to adapt to changing conditions and optimize performance during operation.
Solution Approach 2:
The patent incorporates detection circuits that monitor the operating characteristics of CMUT groups and provide feedback for adjusting the bias voltages. This feedback mechanism enables dynamic optimization of bias signals based on actual device performance, improving adaptability while managing control complexity.
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 enables improved operation of CMUTs by tailoring bias signals to specific groups, enhancing sensitivity and performance consistency across the device, despite manufacturing variations, and allowing for dynamic adjustment of bias voltages during operation.
Implementation Method 1
electrically biasing their membranes by applying a direct current (DC) voltage to a membrane of the CMUTs
Data Source
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AI summary
Electrical biasing of ultrasonic transducers of an ultrasound device is described. The ultrasonic transducers may be capacitive micromachined ultrasonic transducers (CMUTs). The ultrasonic transducers may be grouped together, with the different groups receiving different bias voltages. The bias voltages for the various groups of ultrasonic transducers may be selected to account for differences between the groups.