Non-Contact Potential Measuring Device Natural Frequency Tuning
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Solution Overview
Problem
Conventional non-contact potential measuring devices for charged objects suffer from low measurement sensitivity due to mismatched natural frequencies of vibrating pieces, limiting the amplitude of the chopper electrode and thus the sensitivity of the measurement.
Innovation Solution
A potential measuring device with a first and second shutter, each having a shutter part with an opening, a leaf spring part, and a magnet, where a yoke with a coil applies an alternating magnetic field to cause the shutter parts to reciprocate, and a natural frequency adjusting mechanism, such as an adjusting back yoke and support means, is used to adjust the magnetic force and distance between the magnet and the yoke, ensuring matched natural frequencies between the shutter systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the electromagnetic coil is attached in close vicinity to one of the pair of vibrating pieces, then the structure is simplified, but the natural frequencies of the vibrating pieces do not match and measurement sensitivity deteriorates
Solution Approach 1:
The patent introduces a natural frequency adjusting mechanism that changes the physical parameters of the shutter system by adjusting the magnetic force between the magnet and the adjusting back yoke. This allows the natural frequency of the shutter to be tuned to match the driving frequency, thereby improving measurement sensitivity while maintaining the simplified structure of having the coil attached near one vibrating piece.
2Measurement precision
If the natural frequencies of the vibrating pieces are matched, then measurement sensitivity is improved, but the device complexity increases due to the natural frequency adjusting mechanism
Solution Approach 1:
The patent implements a dynamic adjustment mechanism where the magnetic force between the magnet and the adjusting back yoke can be varied to change the natural frequency of the shutter. This dynamic capability allows the system to adapt and optimize its performance by matching natural frequencies without requiring a completely complex redesign of the overall device structure.
3Measurement precision
If the amplitude of the chopper electrode is increased, then measurement sensitivity is improved, but the natural frequency matching becomes more difficult to maintain
Solution Approach 1:
The patent incorporates a feedback mechanism where the natural frequency of the shutter is adjusted based on the driving frequency of the electromagnetic coil. By using the adjusting back yoke to modify the magnetic force, the system can maintain optimal frequency matching even when operating at higher amplitudes, thus preserving measurement sensitivity without making frequency matching difficult.
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 enhances the measurement sensitivity by allowing larger amplitudes and improved resonance matching, leading to increased sensitivity in detecting the surface potential of charged objects.
Implementation Method 1
a yoke on which a coil is disposed, the coil applying an alternating magnetic field to the magnet of each of the first shutter and the second shutter to cause the shutter part to reciprocate via the leaf spring part
Implementation Method 2
an adjusting back yoke disposed on an opposite side of a side of the leaf spring part that opposes the yoke and adjusting a magnetic force between the adjusting back yoke and the magnet
Data Source
AI summary
There is provided a potential measuring device of non-contact type which can improve measurement sensitivity. A potential measuring device which measures a charged object in a non-contact manner with a sensor includes: a first shutter and a second shutter each having a shutter part provided with an opening and a leaf spring part; a magnet attached to the leaf spring part of each of the first shutter and the second shutter; a yoke on which a coil is disposed, the coil applying an alternating magnetic field to the magnet of each of the first shutter and the second shutter to cause the shutter part to reciprocate via the leaf spring part; and a natural frequency adjusting means for adjusting a natural frequency of at least one of a first shutter system including the first shutter and the magnet and a second shutter system including the second shutter and the magnet.