Shielded Capacitor Circuit for Ion Balance Measurement
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Solution Overview
Problem
Existing ionization balance devices face challenges in accurately measuring and controlling ion balance due to interference from external electromagnetic fields and high impedance, which limits their effectiveness in large areas and sensitive environments.
Innovation Solution
A circuit comprising a capacitor with one exposed and one shielded conductor, along with a resistor and switch, measures ion balance by accumulating and discharging charge to generate feedback signals, ensuring the control signal is independent of external electromagnetic fields and has low impedance, allowing for precise ion balance adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ion balance measurement circuits are used, then ion balance can be measured, but the measurement is interfered with by external electromagnetic fields and has high impedance
Solution Approach 1:
The patent introduces a shielded capacitor circuit as an intermediary measurement mechanism. The capacitor with shielded conductor acts as a mediator between the ion source and the measurement system, blocking external electromagnetic fields while allowing ion charge accumulation. This intermediary structure isolates the measurement from harmful external influences, resolving the contradiction between measurement capability and electromagnetic interference susceptibility.
Solution Approach 2:
The patent replaces conventional high-impedance voltage-based measurement systems with a low-impedance charge accumulation system. By using a capacitor to directly accumulate ion charges and measuring the resulting voltage through a low-impedance resistor, the system substitutes the traditional measurement mechanism, thereby eliminating susceptibility to external electromagnetic fields while maintaining measurement accuracy.
2Measurement precision
If conventional ion balance measurement circuits are used, then ion balance can be measured, but the circuit has high impedance which limits effectiveness in large areas
Solution Approach 1:
The patent replaces the conventional high-impedance measurement circuit with a low-impedance charge accumulation circuit. The capacitor-based measurement system with low-impedance resistor can handle larger ion currents from extended coverage areas without signal degradation, enabling the system to effectively measure ion balance over large areas while maintaining measurement precision.
3Measurement precision
If a capacitor with exposed conductor is used to measure ion output, then ion balance can be quantified, but the measurement is affected by external electromagnetic fields
Solution Approach 1:
The patent introduces a shielded conductor as an intermediary protective layer between the capacitor and the external environment. The shielded conductor blocks external electromagnetic fields from reaching the capacitor, allowing accurate ion output quantification without interference. This intermediary shield resolves the contradiction by preserving measurement accuracy while eliminating electromagnetic susceptibility.
4Reliability
If feedback control is implemented for ion balance, then ion balance can be controlled, but external electromagnetic fields interfere with the control signal
Solution Approach 1:
The patent replaces conventional voltage-based feedback control with a charge accumulation-based control system. By measuring accumulated charge on a low-impedance capacitor rather than voltage signals, the feedback control becomes immune to external electromagnetic field interference. This substitution maintains reliable ion balance control while eliminating the susceptibility to electromagnetic interference that plagues traditional voltage-based control systems.
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 solution effectively measures and controls ion balance with high accuracy, reducing interference from external fields and enabling reliable operation in large areas, such as clean rooms, by using a capacitor with a shielded conductor and a low-impedance resistor to generate feedback signals.
Implementation Method 1
The first conductor accumulates charge so as to quantify the output of the ionization balance device
Implementation Method 2
A switch may be used to discharge the first conductor at periodic intervals in order to measure the accumulated charged on the first conductor
Implementation Method 3
the second one of the conductors is shielded from the output of the ionization device
Data Source
AI summary
In one example, this disclosure describes a circuit and techniques that may be used to measure the ion balance in an ionization balance device (10). The described circuit comprises a capacitor (22) that includes two conductors (23, 24), wherein a first one (23) of the conductors is exposed to the output of the ionization device, and the second one (24) of the conductors is shielded from the output of the ionization device. The first conductor may accumulate charge so as to quantify the output of the ionization balance device. A switch (29) may be used to discharge the first conductor at periodic intervals in order to measure the accumulated charge on the first conductor, and signal processing may be performed on this discharge measurement in order to generate feedback that can be used to control and adjust the output of an ion source.