Planar Electrode Capacitive Sensor for Microfluidic Fluid State Detection
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Solution Overview
Problem
Current methods for detecting the state of fluids in microfluidic plates, such as optical sensors and capacitive sensors, are costly and inefficient, particularly in monitoring separation processes and detecting fluid states accurately.
Innovation Solution
A sensor system comprising a first and second planar electrode arranged parallel to each other to form an electric capacitor, generating an electric field within the fluid, which detects changes in capacitance to determine the state of the fluid, including presence, absence, mixture, fill level, and flow rate, using an alternating current power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are used to monitor separation process and detect fluid state, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex optical sensing systems with a simple capacitive sensor comprising two planar electrodes. This substitution maintains the ability to detect fluid state (presence, absence, mixture) while dramatically reducing device complexity, optical component requirements, and overall system cost.
Solution Approach 2:
The capacitive sensor uses inexpensive planar electrodes that can be integrated into disposable microfluidic cartridges. This approach eliminates the need for expensive, delicate optical components while maintaining detection functionality across multiple uses or disposable units.
2Measurement precision
If optical sensors are used to detect fluid state, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive optical sensing systems with inexpensive capacitive sensors made from planar electrodes. This substitution maintains detection accuracy for fluid state while dramatically reducing manufacturing costs by eliminating optical components, light sources, and associated alignment mechanisms.
Solution Approach 2:
The patent changes the detection parameter from optical properties (light absorption, refraction) to electrical capacitance. This parameter change enables the use of cheap planar electrodes instead of expensive optical components, reducing manufacturing cost while maintaining measurement precision for fluid state detection.
3Measurement precision
If conventional capacitive sensors with active layer are used, then analyte concentration detection is improved, but fluid state detection capability is lost
Solution Approach 1:
The patent removes the active layer from conventional capacitive sensors, extracting only the essential capacitive sensing functionality. This simplification eliminates the limitation of analyte-specific detection while maintaining the ability to detect general fluid state (presence, absence, mixture) through capacitance changes caused by any fluid.
Solution Approach 2:
The patent creates a universal capacitive sensor that can detect the state of any fluid without requiring specific active layers for different analytes. The planar electrode configuration responds to capacitance changes from any fluid presence, providing versatile detection capability across multiple fluid types and applications.
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 sensor system provides a cost-effective and precise method for detecting fluid states in microfluidic plates, enabling reliable monitoring of fluid presence, mixture, fill level, and flow rate, with minimal interference from plate thickness or position inaccuracies.
Implementation Method 1
the sensor detects a change in capacitance indicative of the state of the fluid
Implementation Method 2
the first planar electrode and the second planar electrode are configured to generate an electric field within the fluid
Data Source
AI summary
A sensor (100) for detecting a state of a fluid within a microfluidic plate (120) is disclosed. The sensor (100) comprises at least a first planar electrode (102) and a second planar electrode (104) arranged parallel to one another so as to form an electric capacitor (106). The first planar electrode (102) and the second planar electrode (104) are configured to generate an electric field (114) within the fluid, wherein the sensor (100) is configured to detect the state of the fluid by means of a capacitance of the electric capacitor (106). Further, a system (116) for controlling a preparation of a sample including a fluid is disclosed. Furthermore, a method for detecting a state of a fluid within a microfluidic plate (120) is disclosed.