Ultrasound Transducer Assembly Via Connection Inversion
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Solution Overview
Problem
Existing ultrasound transducer arrays with application-specific integrated circuits suffer from significant parasitic capacitance, leading to low transmit efficiency and poor signal-to-noise ratio due to the connection configuration between electrodes, which complicates manufacturing and reduces signal quality.
Innovation Solution
Inverting the electrical connections by connecting the first electrode of each transducer element to the integrated circuit via the second electrode, using the first electrode as the active electrode and the second electrode as the passive electrode, thereby reducing parasitic capacitance and improving transmit efficiency and signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the second electrodes are individually connected to the application specific integrated circuit, then individual driving signals can be applied to each transducer element, but large parasitic capacitance is formed between the bottom electrode and the top metal layer of the integrated circuit
Solution Approach 1:
The patent inverts the conventional connection configuration by connecting the first electrodes (top electrodes on flexible membrane) individually to the integrated circuit via vias, while connecting all second electrodes (bottom electrodes) together as a common reference. This inversion eliminates the parasitic capacitance problem because the individual connections now go to the top electrodes rather than through the bottom electrodes to the integrated circuit metal layers.
Solution Approach 2:
The patent changes the dimensional approach by routing individual connections vertically through vias from the integrated circuit up to the first electrodes on the flexible membrane, rather than horizontally through the metal layers. This vertical routing through the via dimension avoids the parasitic capacitance formed in the horizontal metal layer plane.
2Loss of energy
If additional floating electrodes are included between the first and second electrode within the cavity, then parasitic capacitance is reduced, but the transducer array structure becomes complicated and manufacturing effort increases
Solution Approach 1:
The patent extracts the parasitic capacitance problem by removing the problematic connection configuration entirely. Instead of adding floating electrodes within the cavity to mitigate parasitic capacitance, the invention extracts the individual connections and routes them through vias to the first electrodes, eliminating the need for additional floating electrodes and simplifying the structure.
3Volume of moving object
If the transducer array is fabricated directly on the top surface of the application specific integrated circuit, then the overall size is reduced, but large parasitic capacitance is formed affecting transmit efficiency and signal to noise ratio
Solution Approach 1:
The patent inverts the connection topology to resolve the contradiction. By connecting individual signals to the first electrodes through vias rather than to the second electrodes through metal layers, the design maintains the compact integrated structure while eliminating the parasitic capacitance that degrades signal 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 configuration enhances the overall transmit efficiency and signal-to-noise ratio, simplifies manufacturing, and reduces the size of the transducer assembly while improving the quality of ultrasound imaging data.
Implementation Method 1
a large parasitic capacitance is formed between the bottom electrode of the transducer elements and the top metal layer of the application specific integrated circuit This parasitic capacitance can be a significant fraction of the cMUT capacitance itself
Data Source
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AI summary
An ultrasound transducer assembly (50), in particular for ultrasound imaging systems (10), is disclosed, comprising a transducer array (52) including a plurality of transducer elements (54) for emitting and receiving ultrasound waves (56). Each of the transducer elements (54) includes a first electrode (66) connected to a flexible membrane (64) and a second electrode (70). The assembly further comprises an integrated circuit device (60) connected to the transducer array (52) for driving the transducer elements (54), wherein the first electrodes (66) are electrically connected to each other and coupled to the integrated circuit device (60) for providing an alternating drive voltage to each of the transducer elements (54), wherein the second electrodes (70) are connected to a voltage supply for providing a bias voltage to the transducer elements (54), and wherein the first electrodes (66) are each connected by means of a via (76) to the integrated circuit device (60) and the vias (76) are fed through the second electrodes (70).