Capacitance Sensor Noise Detection via Electrode Group Summation
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Solution Overview
Problem
Capacitance sensors face challenges in distinguishing between actual object approach signals and high-frequency external noise, leading to erroneous determinations due to the generation of DC noise, which cannot be reduced by averaging detection values.
Innovation Solution
A capacitance sensor with N electrode groups, where each group includes at least one electrode, calculates sum totals of detection values and uses a determination unit to assess noise influence based on sensitivity ratios across predetermined sections, allowing accurate differentiation between noise and actual object approaches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If averaging of detection values is performed to reduce noise, then AC noise is reduced, but DC noise cannot be reduced and erroneous determination occurs
Solution Approach 1:
The detection area is divided into multiple electrode groups, and the sum totals of detection values for each electrode group are compared. By segmenting the detection system into multiple independent groups, the patent enables identification of abnormal patterns caused by DC noise that would be masked in a single averaged measurement.
Solution Approach 2:
The determination unit continuously monitors the relationship between sum totals of different electrode groups and compares them against expected patterns. This feedback mechanism allows real-time detection of DC noise contamination and prevents erroneous determination of object approach.
2Reliability
If multiple electrode groups are used to detect noise, then determination accuracy is improved, but device complexity increases
Solution Approach 1:
The multiple electrode groups serve dual purposes: they function as standard capacitance detection elements for object detection and simultaneously act as noise detection elements through comparison of their sum totals. This multi-functionality reduces the need for separate noise detection hardware.
Solution Approach 2:
The noise detection function is merged with the existing capacitance detection function by utilizing the same electrode groups for both purposes. The sum total comparison mechanism is integrated into the existing detection architecture, avoiding additional complex hardware.
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 determines the presence of high-frequency external noise, ensuring accurate detection of object approaches by maintaining a consistent sensitivity ratio across sections, thus reducing errors caused by noise interference.
Implementation Method 1
capacitance of a capacitor formed between the object and the electrodes for individual electrodes
Implementation Method 2
capacitance sensor that detects an object, such as a finger or a pen, approaching a detection area as a change in electrostatic capacitance
Data Source
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Figure 3A
AI summary
A capacitance sensor includes N electrode groups arranged in a detection area, each of which includes at least one electrode, a capacitance detection unit configured to detect capacitance of capacitors formed between an object and the electrode for individual electrodes, a sum calculation unit configured to add detection values of the capacitance obtained for individual electrodes based on a result of the detection performed by the capacitance detection unit for individual electrode groups so as to calculate sum totals of the detection values for individual N electrode groups, and a determination unit configured to determine whether a detection result of the capacitance detection unit is affected by noise based on the N sum totals calculated for the N electrode groups.