Measurement Device Asymmetric Electrodes Stray Capacitance
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Solution Overview
Problem
Conventional measurement devices for detecting microparticles such as viruses, proteins, and DNA in a liquid phase face challenges in achieving high signal-to-noise ratios and fast response speeds due to increased stray capacitance from complex power source connections, leading to inaccurate measurements of nanoampere or picoampere currents.
Innovation Solution
A measurement device with electrodes made of different metals or alloys in their surface layers, where the ionization tendency of one electrode is less than the other, functions as a battery to facilitate current flow and particle transfer through a micrometer-sized pore, reducing stray capacitance and enhancing signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a complex power source connection is used to provide sufficient voltage for particle transfer, then the transfer control capability is improved, but the stray capacitance increases leading to reduced measurement precision
Solution Approach 1:
The patent combines the power source function with the electrode structure by making the electrode itself serve as the power source. The first electrode and second electrode are directly connected to the measurement target through the pore, eliminating separate complex power source connections and reducing stray capacitance while maintaining sufficient voltage for particle transfer.
Solution Approach 2:
The patent extracts and eliminates the complex power source connection system from the measurement device. By using the electrode potential difference directly as the power source, the design removes unnecessary intermediate connections that contribute to stray capacitance, simplifying the overall system architecture.
2Reliability
If the electrode surface area is increased to reduce contact resistance, then the electrical connection is improved, but the stray capacitance increases reducing response speed
Solution Approach 1:
The patent applies local quality by concentrating the electrical connection function at specific localized points (the pore region) rather than distributing it over large electrode surfaces. The electrode surfaces are kept minimal in area contacting the measurement target, with the pore serving as the focused connection point that provides sufficient electrical contact without excessive capacitance.
3Ease of manufacture
If conventional same-material electrodes are used, then the manufacturing is simplified, but the ionization tendency difference required for effective particle transfer is not achieved
Solution Approach 1:
The patent applies asymmetry by using electrodes made of different materials with distinct ionization tendencies. The first electrode and second electrode are deliberately designed with different material compositions to create the necessary potential difference for effective particle transfer, accepting the increased manufacturing complexity as a trade-off for improved transfer efficiency.
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 configuration allows for precise measurement of particle size by amplifying weak currents and reducing noise, improving the accuracy and speed of detecting microparticles with higher signal-to-noise ratios compared to conventional devices.
Implementation Method 1
the first and second electrodes contain different metals or alloys at least in surface layers thereof, and a relationship of Ia12 is made of the ionization tendency Ia of the metal or alloy contained at least in the surface layer of the first electrode 12 and the ionization tendency Ib of the metal or alloy contained at least in the surface layer of the second electrode 13
Implementation Method 2
the potential of the first electrolytic solution with target particles dispersed therein is set to be negative and the potential of the second electrolytic solution is set to be positive. In this state, a repulsive force works on the negatively-charged target particles in the first electrolytic solution of negative potential, and the particles are electrically transferred to the second electrolytic solution through the pore
Data Source
AI summary
According to one embodiment, a measurement device includes a first chamber, a second chamber, a partition provided between the first and second chambers, a through hole which is provided in the partition and with which the first chamber and the second chamber communicate each other, a first electrode provided in the first chamber, and a second electrode provided in the second chamber. The first electrode and the second electrode contain different metals or alloys at least in surface layers thereof, and a relationship of Ia<Ib is satisfied, where Ia is an ionization tendency of a metal or an alloy contained at least in the surface layer of the first electrode and Ib is an ionization tendency of a metal or an alloy contained at least in the surface layer of the second electrode.