Proximity Detection Circuit With Adjustable Shield Frequency
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Solution Overview
Problem
Existing detection devices experience interference due to frequency mismatch between the periodically oscillating potential of the shield electrode and external signals, leading to reduced detection accuracy.
Innovation Solution
A detection device with a power circuit generating a square wave, a filter coupled through an isolator, and a digital potentiometer that adjusts the frequency of the periodically oscillating potential to minimize interference, using a low-pass filter and amplifier to generate a sine wave for accurate proximity detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a periodically oscillating potential is provided to the shield electrode, then the detection device can reduce noise and improve detection accuracy, but the frequency of the oscillating potential may interfere with external periodically oscillating signals
Solution Approach 1:
The patent applies dynamics by making the frequency of the periodically oscillating potential adjustable rather than fixed. The frequency can be dynamically changed to avoid interfering with external signals while maintaining effective noise reduction. This is achieved through a frequency adjustment mechanism that allows the system to adapt the oscillation frequency to different operational conditions and avoid known interference frequencies.
Solution Approach 2:
The patent employs parameter changes by modifying the frequency parameter of the periodically oscillating potential applied to the shield electrode. By changing this parameter, the system can optimize noise reduction performance while avoiding interference with external signals at specific frequencies. The ability to adjust the frequency parameter allows the detection device to maintain high detection accuracy without suffering from signal interference.
2Device complexity
If the frequency of the periodically oscillating potential is fixed, then the circuit design is simpler, but the device cannot adapt to avoid interference with external signals at different frequencies
Solution Approach 1:
The patent transforms the static frequency into a dynamic parameter that can be adjusted. The frequency adjustment mechanism allows the system to adapt to different operational environments and avoid interference frequencies. This dynamic capability is implemented through additional circuit elements that enable frequency modulation while maintaining overall system manageability.
Solution Approach 2:
The patent enhances universality by designing the shield electrode circuit to perform multiple functions: noise reduction at the operating frequency and adaptability to avoid external interference. The frequency adjustment capability allows the same circuit to effectively operate across different frequency conditions, making the detection device more versatile and applicable in various electromagnetic environments.
3Ease of manufacture
If a square wave is generated by the power circuit, then the signal is easy to generate and process, but the square wave contains high-frequency components that may increase noise
Solution Approach 1:
The patent applies preliminary action by filtering the square wave signal before it is used to generate the periodically oscillating potential for the shield electrode. A low-pass filter is implemented to remove high-frequency components from the square wave, converting it into a smoother sinusoidal-like waveform. This preliminary filtering action prevents high-frequency noise from being introduced into the detection system while maintaining the ease of square wave generation.
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 device effectively reduces interference by dynamically adjusting the frequency of the square wave and oscillating potential, enhancing the accuracy of proximity detection and reducing noise, thereby improving the reliability of hover detection.
Implementation Method 1
The filter includes a low-pass filter circuit and a digital potentiometer
Implementation Method 2
a filter that is coupled to the power circuit through an isolator
Implementation Method 3
an amplifier configured to amplify a signal output from the filter
Implementation Method 4
The filter is provided capable of changing the frequency of the periodically oscillating potential in accordance with an electric resistance value of the digital potentiometer
Implementation Method 5
a detection circuit configured to detect proximity of an external object to the detector based on electric change at the first electrodes
Data Source
AI summary
A detection device includes: a detector including first electrodes and second electrodes disposed around a the first electrodes; a detection circuit configured to detect proximity of an external object to the detector; a power circuit configured to generate a square wave; and a filter that is coupled to the power circuit through an isolator and configured to receive the square wave transmitted through the isolator. The filter includes a low-pass filter circuit and a digital potentiometer. A periodically oscillating potential based on output from the filter is provided as a reference potential of the power circuit and provided to the second electrodes. A reference potential of the filter is a fixed potential. The power circuit can change the frequency of the generated square wave. The filter can change the frequency of the periodically oscillating potential in accordance with an electric resistance value of the digital potentiometer.