Ultrasonic Vibration Sub-element with Separate DC and AC Electrodes
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Solution Overview
Problem
Current capacitive micromachined ultrasound transducers (CMUTs) require a bias tee circuit to drive the membrane, leading to a large system volume due to the need for separate integration of alternating current (AC) and direct current (DC) into electrodes.
Innovation Solution
The ultrasonic vibration sub-element design includes a substrate, ground layer, insulation layers, and separate electrode layers for receiving DC and AC signals. This configuration allows the ultrasonic vibration sub-element to be driven without a bias tee, reducing the system volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bias tee circuit is used to drive the CMUT membrane, then the membrane can be properly driven with integrated AC and DC, but the system volume becomes huge
Solution Approach 1:
The patent divides the driving function into two separate electrode layers: a first electrode layer for receiving DC voltage and a second electrode layer for receiving AC signals. This segmentation eliminates the need for a bias tee circuit, reducing system volume while maintaining the ability to properly drive the membrane
Solution Approach 2:
The patent merges the DC and AC driving functions into a single integrated structure with multiple electrode layers, where both functions are implemented within the transducer assembly itself rather than requiring separate external bias tee circuitry
2Ease of operation
If separate electrode integration for AC and DC is implemented, then proper membrane driving is achieved, but device complexity increases
Solution Approach 1:
The electrode structure is segmented into distinct first and second electrode layers with different insulation layers, where each layer handles a specific function (DC or AC). This clear segmentation simplifies the control logic while achieving proper membrane driving
Solution Approach 2:
The patent transitions from a planar electrode structure to a multi-layer stacked architecture, adding the vertical dimension with multiple electrode and insulation layers. This dimensional change allows independent AC and DC pathways without increasing lateral 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
The solution reduces the system volume by eliminating the need for a bias tee and lowering the DC voltage value, while also enabling a wider application range, such as in handheld ultrasound probes, with reduced manufacturing time and cost.
Implementation Method 1
the first electrode layer receives the direct current voltage and is configured to at least drive the second insulation layer to shrink toward the cavity
Implementation Method 2
the second electrode layer receives the alternating current signal and is configured to at least drive the third insulation layer to vibrate
Data Source
AI summary
An ultrasonic vibration sub-element including a substrate, a ground layer, a first insulation layer, a second insulation layer, a first electrode layer, a third insulation layer, and a second electrode layer is provided. The first electrode layer is configured to receive a direct current voltage. The second electrode layer is configured to receive an alternating current signal. Before the ultrasonic vibration sub-element is driven, there is a cavity between the first insulation layer and the second insulation layer. When the ultrasonic vibration sub-element is driven, the first electrode layer receives the direct current voltage and is configured to at least drive the second insulation layer to shrink toward the cavity. The second electrode layer receives the alternating current signal and is configured to at least drive the third insulation layer to vibrate. An ultrasound probe is also provided.