Adaptive Charge Neutralization With Feedback Ion Balance Control
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Solution Overview
Problem
Conventional charge neutralizers lack feedback mechanisms to accurately determine whether the predetermined balance of positive and negative ions is appropriate for the charge present at the target during operation.
Innovation Solution
The apparatus for adaptive charge neutralization modulates a high voltage, high frequency AC signal using a DC offset signal to control the generation of positive and negative ions, and adjusts the duty cycles of the DC offset signal based on balance voltage feedback to achieve an accurate ion balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional charge neutralizers use a predetermined balance of positive and negative ions, then the device structure is simple, but the measurement precision of ion balance is insufficient
Solution Approach 1:
The patent implements a feedback mechanism where a sensor detects the charge level on the substrate and sends signals to the controller, which then adjusts the ion emission balance accordingly. This closed-loop feedback system enables real-time monitoring and adjustment of ion balance, resolving the contradiction between measurement precision and device complexity by introducing intelligence to the system.
Solution Approach 2:
The patent replaces manual adjustment mechanisms with automated electronic control systems. The controller uses electronic signals to adjust the ion emission parameters based on sensor feedback, substituting mechanical adjustment with electronic automation. This reduces the need for complex manual mechanisms while improving measurement precision through automated control.
2Adaptability or versatility
If conventional charge neutralizers emit fixed ion balance, then the operation is simple, but the adaptability to different charge conditions is poor
Solution Approach 1:
The patent transforms the static, fixed ion emission system into a dynamic one where the ion balance automatically adjusts based on real-time charge conditions. The controller dynamically modifies the emission parameters in response to sensor feedback, enabling the system to adapt to varying charge conditions while maintaining simple operation through automation.
Solution Approach 2:
The system performs self-adjustment by automatically detecting charge conditions and modifying its own ion emission parameters without external intervention. The controller and sensor work together to enable the system to self-regulate, improving adaptability while keeping the operation simple for the user.
3Reliability
If high voltage is used to generate corona discharge, then ion generation is effective, but the swing voltage causes instability in voltage-sensitive applications
Solution Approach 1:
The patent changes the voltage parameter characteristics by using pulse-width modulation (PWM) to control the duty cycle of the high voltage supply. Instead of maintaining a constant high voltage that causes large swings, the system uses variable duty cycles to deliver controlled amounts of high voltage only when needed for ion generation, thereby maintaining ion generation effectiveness while reducing harmful voltage swings that affect sensitive 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
This approach results in more accurate balance voltages and significantly reduced swing voltages, improving the effectiveness of charge neutralization, especially in voltage-sensitive and charge-sensitive applications like semiconductor manufacturing.
Implementation Method 1
In the ionization cell, at least one electrode is an ion emitter and another one may be a reference electrode. To generate gas ions, the amplitude of the applied voltage must be high enough to produce a corona discharge between at least two electrodes arranged as an ionization cell.
Implementation Method 2
control circuitry configured to: provide a polarity signal to the power supply to generate a DC offset signal, wherein a combination of the high frequency AC signal and the DC offset signal causes the power supply to output a positive ion generation pulse or a negative ion generation pulse
Data Source
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AI summary
An example apparatus for charge neutralization includes: a first emitter nozzle; a power supply configured to supply a high frequency alternating current (AC) signal to the first emitter nozzle; control circuitry configured to: provide a polarity signal to the power supply to generate a DC offset signal, wherein a combination of the high frequency AC signal and the DC offset signal causes the power supply to output a positive ion generation pulse or a negative ion generation pulse; control the polarity signal to cause the power supply to provide a period of positive ion generation and a period of negative ion generation; determine a balance voltage at an output of the first emitter nozzle; and control the polarity signal to adjust a relative durations of the period of positive ion generation and the period of negative ion generation based on the balance voltage.