Omnidirectional Spiral SAW Generation for Sessile-Drop Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surface acoustic wave (SAW) technologies for fluid manipulation and particle separation face challenges such as anisotropic substrates, difficulty in accurately placing sessile drops, and significant energy losses due to offset positions, complicating their use in clinical settings and reducing efficiency and repeatability.
Innovation Solution
An omnidirectional spiral surface acoustic wave (OSSAW) device with a rotationally symmetric design and spiral formation that generates SAWs from all directions, using a piezoelectric material with a 152 degree Y-rotated cut of lithium niobate (LN) to propagate waves in multiple directions, minimizing in-plane anisotropy and maximizing electromechanical coupling, and includes an extraction system for efficient particle separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If straight interdigital transducers with offset position are used for fluid manipulation, then fluid spinning and particle separation can be achieved, but significant energy losses occur and anisotropic substrates complicate the system
Solution Approach 1:
The patent applies asymmetry by using an offset position of the straight IDT relative to the sessile drop center, creating asymmetric SAW actuation properties that enable fluid spinning and particle separation. This asymmetric configuration is deliberately designed to generate the required fluid dynamics for separation applications.
Solution Approach 2:
The patent transitions from straight IDT to a curved/spiral IDT configuration that matches the curvature of the sessile drop. This curved transducer design enables omnidirectional SAW generation around the drop perimeter, improving energy transfer efficiency and eliminating the need for offset positioning, thereby reducing energy losses while maintaining separation functionality.
2Productivity
If offset position is used for particle separation, then separation functionality is achieved, but difficulty in accurately placing sessile drops and significant energy losses occur
Solution Approach 1:
The patent segments the transducer into multiple finger elements arranged in a spiral/curved configuration around the drop. This segmentation allows each finger to contribute to omnidirectional SAW generation, eliminating the need for a single offset position and enabling accurate drop placement without compromising separation functionality.
Solution Approach 2:
The curved/spiral transducer design follows the curvature of the sessile drop, enabling uniform SAW generation from all directions around the drop. This eliminates the offset positioning requirement and makes the system less sensitive to drop placement accuracy while maintaining effective particle separation.
3Productivity
If straight IDT with offset position is used, then particle concentration and separation are achieved, but device complexity increases due to anisotropic substrates
Solution Approach 1:
The curved/spiral IDT design provides multi-functionality by enabling both fluid spinning and particle separation through omnidirectional SAW generation from a single transducer configuration. This eliminates the need for complex offset positioning and anisotropic substrate requirements, simplifying the overall device while maintaining separation performance.
Solution Approach 2:
The curved transducer design naturally adapts to the sessile drop geometry, providing universal applicability for different drop sizes and viscosities. This geometric adaptation simplifies the device configuration by eliminating the need for precise offset positioning and complex substrate orientation, reducing device complexity while maintaining separation effectiveness.
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 OSSAW device enables efficient fluid spinning and particle separation in a sessile droplet without micro or nanoscale enclosures, facilitating rapid cell separation and extraction for point-of-care diagnostics, with improved energy transfer and reduced anisotropy, enhancing the efficiency and accuracy of particle separation.
Implementation Method 1
a piezoelectric material configured to convert electric energy into the plurality of acoustic waves
Implementation Method 2
The plurality of acoustic waves may induce acoustic streaming along the piezoelectric material in multiple directions to isolate a fluid component within a fluid located on the acoustic wave device
Data Source
AI summary
Articles of manufacture, including an apparatus for omnidirectional spiral surface acoustic wave generation, are provided. An acoustic wave device that generates a plurality of acoustic wave includes a piezoelectric material to convert electric energy into the plurality of acoustic waves. The acoustic wave device also includes a transducer. The transducer includes a plurality of fingers arranged in a spiral formation. The plurality of acoustic waves induce acoustic streaming along the piezoelectric material in multiple directions to isolate a fluid component within a fluid located on the acoustic wave device.