Time-Frequency SAW Composite Fabrication for Local Particle Patterning
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Solution Overview
Problem
Current methods for fabricating heterogeneous smart composite materials using surface acoustic waves (SAWs) lack regional position selectivity, limiting their application and complexity in dynamic control, especially when using lithium niobate wafers.
Innovation Solution
A device and method employing time-frequency regulated SAWs with slanted-finger interdigital transducers on a lithium niobate wafer, generating standing SAWs in a liquid tank filled with a photosensitive mixture, allowing for controlled distribution of functional particles through acoustic radiation forces and subsequent UV photocuring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SAW-assisted arrangement is used to fabricate heterogeneous smart composite material, then functional particles can be arranged in fluid without special requirements for shape and physical properties, but the functional particles are usually arranged in a single array with poor regional position selectivity
Solution Approach 1:
The patent divides the single interdigital transducer into multiple interdigital transducers (first, second, third, and fourth transducers) arranged in pairs. Each transducer pair can independently generate acoustic fields in specific regions, enabling segmented control of particle arrangement in different areas of the liquid container, thus achieving regional position selectivity while maintaining versatility with different functional media
Solution Approach 2:
The patent employs dynamic control of acoustic field parameters including frequency modulation and phase difference adjustment between transducer pairs. By dynamically changing the excitation frequencies and phase relationships, the system can selectively position particles in different regions and create various heterogeneous distribution patterns, resolving the contradiction between adaptability and manufacturing precision
2Manufacturing precision
If waveguide structure or acoustic boundary change is used to control particle arrangement region, then regional selectivity can be achieved, but the operation becomes complicated and hard for dynamic control
Solution Approach 1:
The patent replaces mechanical modifications (waveguide structures and acoustic boundary changes) with electronic control of multiple transducers. By using electronic frequency and phase modulation of the transducer excitation signals, the system achieves dynamic regional control of particle arrangement without any mechanical structure changes, thereby improving ease of operation and dynamic control capability while maintaining manufacturing precision
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
Enables precise, localized distribution of functional particles, enhancing the diversity and application of heterogeneous composite materials in biomedicine and wearable electronics by achieving regional selectivity and stability in particle arrangement.
Implementation Method 1
a pair of slanted-finger interdigital transducers are distributed on a lithium niobate wafer; the pair of slanted-finger interdigital transducers are respectively excited by sinusoidal signals to generate SAWs of different frequencies
Implementation Method 2
allowing for controlled distribution of functional particles through acoustic radiation forces
Implementation Method 3
an ultraviolet (UV) light source is fixed under the lithium niobate wafer; subsequent UV photocuring
Data Source
AI summary
A device and method for preparing a locally heterogeneous smart composite material based on time-frequency regulated SAWs are provided. The method includes: mixing functional particles, a photosensitive liquid and a photoinitiator evenly; inputting periodic time-frequency regulated sinusoidal signals defined by a frequency, a duration, an interval time and a time difference to a pair of slanted-finger interdigital transducers, such that the pair of slanted-finger interdigital transducers are excited to produce corresponding standing SAWs; coupling and allowing the standing SAWs to enter a liquid tank to form a local sound field in the photosensitive liquid; forming, by the functional particles in the photosensitive liquid, a stable array distribution under the action of an acoustic radiation force of the local sound field; and turning on an UV light source for curing, thereby completing the preparation.