Optical Liquid Level Detection in Disposable Tips
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid handling systems face challenges in accurately detecting liquid levels and tip states, particularly for high-viscosity fluids and in ambient conditions, due to limitations in pressure-based methods and the need for specialized tips.
Innovation Solution
A liquid handling system utilizing optical methods with a light source and detectors positioned to interact with the tip and liquid surface, employing time-of-flight and photometric principles to measure liquid levels and volumes independently of ambient conditions, capable of detecting clogging and suitable for both hand-held and automated systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure measurement methods are used for liquid level detection, then the system can detect liquid level changes, but the accuracy decreases for high viscosity fluids and is affected by ambient pressure and altitude
Solution Approach 1:
The patent replaces pressure-based mechanical measurement with optical measurement. Light is directed through the tip material and the liquid column, and the liquid level is detected by measuring light transmission or reflection properties. This optical system is not affected by ambient pressure changes or fluid viscosity, as it measures optical path properties rather than pressure differential.
Solution Approach 2:
The patent introduces light as an intermediary medium to detect liquid level. Instead of directly measuring pressure, the system uses light transmission through the tip and liquid column as an intermediate measurement that indirectly indicates liquid level while being immune to pressure and viscosity effects.
2Measurement precision
If specialized tips with optical structures are used for photometric detection, then liquid level can be detected optically, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent makes the conventional disposable tip serve an additional optical function. The tip material itself acts as an optical element through which light is transmitted. No separate optical structures are needed within the tip - the tip's inherent material properties are utilized for optical measurement, allowing conventional tips to be used.
Solution Approach 2:
The patent enables conventional disposable tips to serve dual functions: their original liquid handling function and an additional optical measurement function. The same tip structure is used for both dispensing liquid and transmitting light for level detection, eliminating the need for specialized optical tips.
3Device complexity
If conventional disposable tips are used without optical modifications, then the device complexity is low, but photometric detection of liquid level cannot be implemented
Solution Approach 1:
The patent replaces the need for mechanical/optical modifications to the tip with an external optical system. Light sources and detectors are positioned outside the tip, and light is directed through the tip material using external optical elements. This allows conventional tips to be used while achieving photometric detection capability.
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 system provides accurate and reliable liquid level detection and tip monitoring, independent of ambient pressure and fluid viscosity, enabling real-time measurement of liquid volumes and detecting clogging, suitable for a wide range of dispensing volumes and conventional disposable tips.
Implementation Method 1
The system comprises a time-of-flight component which is located inside a cylinder of the liquid handling system
Implementation Method 2
employing time-of-flight and photometric principles to measure liquid levels and volumes
Implementation Method 3
Light is passed through the tip material. Contact of the tip and a fluid is detected optically by detecting a change in the light reflected from an outer surface of the tip
Data Source
Figure 1
Figure 2
Figure 3
AI summary
According to an example aspect of the present invention, there is provided a liquid handling system for dispensing a liquid sample from a tip. The system comprises a light source configured to project a first beam of light via a first optical path that interacts with the tip or its contents, and further configured to direct a second beam of light via a second optical path that does not interact with the tip and its contents; a first detector configured to detect the first beam of light; a second detector configured to detect the second beam of light; an analysis unit configured to analyse a state of the tip on the basis of signals obtained from the first and second detectors; wherein the second detector is a normalization detector configured to measure intensity of the light source.