Microvolume Analysis System Using Surface Tension Drop Control
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Solution Overview
Problem
Existing spectrophotometers are unsuitable for analyzing small liquid volumes due to complexity, difficulty in cleaning, and high costs, as they often rely on bulk samples and numerous automated moving parts.
Innovation Solution
The development of a spectrophotometer that utilizes surface tension to maintain a reproducible drop shape for small volumes of liquid, employing a drop-supporting surface designed to dominate over gravitational forces, with integrated optical components and a mounting body that supports multiple dropheads for accurate measurement and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If automated moving parts are used to handle small liquid volumes, then measurement capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential measurement function from complex automated handling systems. By using a simple flat surface to support drops and allowing manual or minimal automation for drop placement, the system removes unnecessary moving parts while retaining the core capability to measure small liquid volumes optically.
Solution Approach 2:
The patent uses optical copying principles where light passes through or reflects from the drop to create an optical signal that replicates the physical properties of the liquid sample. This allows measurement without direct mechanical interaction with the sample, reducing the need for complex handling mechanisms.
2Extent of automation
If samples are supported in the middle of complex machinery, then automated handling is improved, but ease of cleaning deteriorates
Solution Approach 1:
The patent segments the measurement system into a separate, accessible drop support surface that can be independently cleaned or replaced. The flat surface is designed as a distinct component that can be accessed without disassembling the entire instrument, allowing easy cleaning between samples while the rest of the automated optical system remains intact.
Solution Approach 2:
The patent considers using disposable drop support surfaces or easily replaceable components. Instead of cleaning complex internal surfaces, the system can use inexpensive, single-use support elements that are discarded after one measurement, eliminating cleaning requirements entirely while maintaining automated measurement capabilities.
3Measurement precision
If surface tension dominates over gravitational forces, then drop shape reproducibility is improved, but measurement volume is constrained
Solution Approach 1:
The patent changes the surface energy parameters of the support surface to control drop shape. By adjusting surface properties (such as using hydrophobic or hydrophilic coatings), the system can maintain reproducible drop shapes across a range of volumes. This allows the use of surface tension dominance for precision while extending the usable volume range through surface property modification rather than being strictly limited to very small volumes.
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 accurate measurement of optical properties in small liquid volumes with improved reproducibility and versatility, reducing complexity and cost while allowing for automated analysis of multiple samples.
Implementation Method 1
The invention relies on the phenomenon of surface tension to ensure a reproducible drop shape for a given volume. By dimensioning the drop-supporting surface to ensure that surface tension dominates over gravitational forces, the shape of the drop - and hence its interaction with radiation - is reproducible for a constant composition.
Implementation Method 2
said source and/or said detector comprises an optical fiber terminating below said surface of said drophead for transmitting and/or receiving said electromagnetic radiation to and/or from said received drop of liquid through said transparent drophead
Implementation Method 3
detecting said radiation following an interaction with said liquid drop
Data Source
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AI summary
An analyser comprising a source of electromagnetic radiation, a detector for said radiation and a drophead comprising a surface which is adapted to receive a drop of liquid to be tested, the drophead being positioned in use relative to the source and detector to illuminate a drop received thereon and to cause an interaction in the path of the electromagnetic radiation between the source and detector, characterised in that said surface of said drophead is dimensioned to constrain the drop to adopt a shape which is dominated more by surface tension forces than by gravitational forces.