Passive Wireless Microfluidic Droplet Detection via Double-Resonance Circuit
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Solution Overview
Problem
Current droplet detection methods, such as acoustic, optical, inductance, and capacitance detection, face limitations like noise susceptibility, environmental interference, and the need for external power sources, making them inefficient for rapid and accurate measurement of droplet speed, flow rate, size, and quantity, especially for multi-level droplets.
Innovation Solution
A passive wireless device with a microfluidic chip substrate, featuring a detection channel, droplet generation structures, and a double-resonance circuit formed by inductor and capacitor channels, allowing non-contact detection of droplet parameters through resonant frequency changes without external power, reducing device size and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic detection method is used, then droplet parameters can be detected, but the detection is susceptible to noise and vibration
Solution Approach 1:
The patent replaces acoustic detection (mechanical wave-based) with electromagnetic resonance detection. The droplet's electromagnetic properties (permittivity and conductivity) are measured through resonance frequency changes in an oscillating circuit, eliminating susceptibility to mechanical noise and vibration while maintaining measurement capability.
Solution Approach 2:
The patent measures droplet parameters by detecting changes in electromagnetic parameters (resonance frequency, permittivity, conductivity) rather than mechanical parameters. This parameter transformation allows accurate detection without being affected by mechanical disturbances.
2Measurement precision
If optical detection method is used, then droplet parameters can be detected, but the detection is susceptible to environmental factors such as temperature and oil permeability
Solution Approach 1:
The patent replaces optical detection with electromagnetic resonance detection. By measuring the droplet's electrical properties (permittivity and conductivity) through their effect on resonance frequency, the system avoids susceptibility to optical environmental factors like temperature variations and oil permeability.
Solution Approach 2:
The patent transforms the detection approach from optical parameters to electromagnetic parameters. The droplet's electrical characteristics modify the resonance circuit's frequency, providing a detection mechanism insensitive to optical environmental interference.
3Measurement precision
If inductance detection method or capacitance detection method is used, then droplet parameters can be detected, but external power source and connection leads are required which limit application
Solution Approach 1:
The patent implements a passive detection system where the droplet itself serves as the sensing element. The droplet's electrical properties directly modulate the resonance frequency of the oscillating circuit without requiring external power sources or connection leads, enabling wireless and contactless detection applications.
Solution Approach 2:
The patent creates a detection system that can operate in diverse applications (medical, industrial, research) without requiring infrastructure for external power or connections. The self-contained resonance circuit with droplet-as-sensor design provides universal applicability across different environments and scenarios.
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, single-step detection of multi-level droplet parameters with reduced device size and extended lifespan, minimizing errors and expanding application possibilities by eliminating external interference and power source dependencies.
Implementation Method 1
the primary inductor channel and the secondary inductor channel are alternately arranged in each layer; the primary capacitor channel is connected to the primary inductor channel, the secondary capacitor channel is connected to the secondary inductor channel, and the primary inductor channel is connected to the secondary inductor channel; a liquid conductive material is injected into the primary capacitor channel, the primary inductor channel, the secondary capacitor channel, and the secondary inductor channel, to form a double-resonance circuit
Implementation Method 2
when a first droplet group passes through the first part, the permittivity of the primary capacitor channel changes and consequently a capacitance value of the primary capacitor channel changes, resulting in a change in a first resonant frequency of the double-resonance circuit
Data Source
AI summary
Disclosed is a passive wireless device for microfluidic detection of multi-level droplets. A primary inductor channel and a secondary inductor channel each comprise two layers of inductance coils, and the inductance coils of the primary inductor channel and the secondary inductor channel are alternately arranged in each layer. A double-resonance circuit is formed after a liquid conductive material is injected. A first part of a detection channel is disposed between a primary capacitor channel, and a second part of a detection channel is disposed between a secondary capacitor channel. A reading device is used to read a resonant frequency of the double-resonance circuit, and perform detection according to the resonant frequency to obtain information of a corresponding first droplet group and/or second droplet group.