Capacitive Vehicle Input Detection Using Multi-Electrode Signal Integration
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Solution Overview
Problem
Capacitive input apparatuses in vehicles face erroneous detection due to external noise, such as vibrations, which complicates distinguishing between actual operation changes and noise-induced changes in capacitance.
Innovation Solution
The input apparatus includes a plurality of electrodes spaced apart, with a signal processing unit generating input signals based on capacitance changes and a determination unit that considers threshold values and integral values over a predetermined period to accurately determine the proximity of an operation object, reducing erroneous detections by accounting for changes in adjacent electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse generation circuits are provided in each detection unit to reduce erroneous detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the pulse generation function from individual detection units into a single shared pulse generation circuit that serves all detection units. This consolidation reduces the overall number of circuits while maintaining the ability to perform differential capacitance measurement across multiple electrodes, thereby reducing device complexity without sacrificing measurement precision.
Solution Approach 2:
The shared pulse generation circuit is designed to serve multiple detection units simultaneously, making it a universal component that performs the same function for all electrodes. This multi-functional approach eliminates the need for duplicate pulse generation circuits in each detection unit, reducing overall system complexity while maintaining detection accuracy through differential measurement.
2Reliability
If multiple electrodes are monitored with individual pulse generation circuits to reduce noise interference, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple individual pulse generation circuits into a single shared circuit that can drive all detection units. This merging approach maintains reliable detection across multiple electrodes by enabling differential measurement comparison, while simultaneously reducing the overall circuit configuration complexity by eliminating redundant pulse generation components.
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 effectively reduces erroneous detections by integrating signals from multiple electrodes, allowing for precise detection of operation objects while minimizing noise interference, thus enhancing the reliability of input operations in noisy environments.
Implementation Method 1
an input operation is performed by detecting a change in capacitance that occurs when an operation object such as a finger of an operator, a touch pen, or the like is brought in the proximity of the input apparatus
Data Source
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AI summary
An input apparatus (10) includes a plurality of electrodes (1a, 1b, 1c) spaced apart from each other, a signal processing unit (11) configured to output an input signal depending on a change in a capacitance of each electrode (1a, 1b, 1c), and a determination unit (12) configured to determine whether an operation object comes in a proximity of at least one of electrodes (1a, 1b, 1c) based on input signals output from the signal processing unit (11). The determination unit (12) makes a determination such that in a case where one of the input signals is greater than or equal to a first threshold value and an integral value of another of the plurality of input signals in a predetermined integration period is greater than or equal to a second threshold value, it is determined that an operation object has come in a proximity of an electrode (1a, 1b, 1c) corresponding to the one of the input signals.