Bubble Nucleation via Focused Ion Beam Pits
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Solution Overview
Problem
Generating bubbles of a selected small size within a small diameter tube is difficult due to challenges in precise deposition of nucleation sites, such as gallium or gallium alloys, which are often limited to the tube tip and prone to imperfections.
Innovation Solution
A delivery tube with a smooth internal surface, free of defects, is augmented with precisely formed nucleation sites using focused ion beam (FIB) to create pits or crevices, allowing for controlled bubble nucleation and size regulation through laminar flow, ensuring bubbles are sheared to a small diameter before exiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deposition of gallium or gallium alloy is used to create nucleation sites, then bubble nucleation can be controlled, but the deposition is difficult and imprecise in small diameter tubes
Solution Approach 1:
The patent replaces the mechanical deposition process (dipping or painting liquid gallium) with a focused ion beam (FIB) system that uses ion bombardment to sputter and deposit gallium atoms precisely at targeted locations on the tube interior surface, achieving sub-micron placement accuracy
Solution Approach 2:
The FIB system deposits gallium material only at specific localized regions on the tube interior surface where nucleation sites are needed, rather than coating the entire surface, enabling precise control of nucleation location and quality
2Manufacturing precision
If agitation methods are used to generate bubbles, then bubbles can be produced, but the bubble size cannot be precisely controlled and remains in a broad range
Solution Approach 1:
The patent controls bubble size by precisely controlling the nucleation site geometry (pits or crevices) and the saturation pressure of the carrier liquid, rather than relying on agitation intensity. By changing these parameters, bubble diameter can be controlled within 10-100 micrometers
Solution Approach 2:
The nucleation sites (pits or crevices) are pre-formed on the tube interior surface before bubble generation begins. This preliminary structuring of the surface ensures that bubbles nucleate at predetermined locations with controlled initial size, eliminating the need for agitation-based size control
3Reliability
If a smooth tube surface is used, then the tube is free of defects, but nucleation sites cannot be formed without additional processing
Solution Approach 1:
The patent uses focused ion beam (FIB) technology to create nucleation sites on the smooth tube interior surface through ion bombardment and sputtering, replacing the need for mechanical surface roughening or defect introduction while maintaining the inherent smoothness and sterility of the tube
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 method efficiently delivers a large number of bubbles with diameters at or less than one micron, enhancing echogenic contrast and facilitating precise medical procedures by maintaining bubble size consistency and sterility.
Implementation Method 1
The FIB is used to form pits or crevices on the inner surface of the tube on the size of about 0.01 nanometers (nm) to about five microns
Implementation Method 2
The bubbles may be generated or nucleated on a surface from gas dissolved in a fluid
Implementation Method 3
The high flow rate of the fluid may ensure or generate small bubbles as they are sheared soon after bubble nucleation and formation begins
Data Source
AI summary
Generation of bubbles is disclosed to occur within a flow of an aqueous fluid. The bubbles may be formed within a tube of a selected diameter and the bubbles are controlled to exit the tube at a selected diameter. Generally, bubbles are formed to include a diameter of less than 1 millimeter, including less than about 20 microns.