Capacitive Switch with Combined-Capacitance Measurement
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Solution Overview
Problem
Conventional capacitive switches face issues with erroneous operations due to environmental influences like temperature and moisture, and they have durability problems due to mechanical components, leading to inaccurate touch detection and reduced lifespan.
Innovation Solution
A capacitive switch device with a touch sensing unit and a touch control module that uses combined-capacitance measurement, where the sensing electrode and transmission electrode are activated in specific modes to detect human body touch more precisely, minimizing environmental impact and component wear by continuously updating a reference value based on capacitance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional mechanical switch is used, then the switch can be operated physically, but it causes erroneous operations and reduces life cycle due to abrasion of consumable components
Solution Approach 1:
The patent replaces the mechanical switch system with a capacitive touch sensing system. The mechanical components (springs, contacts, levers) are substituted with electrical components (sensing electrode, transmission electrode, control module) that detect touch through capacitance changes rather than physical contact, thereby eliminating wear and extending life cycle
2Reliability
If a conventional capacitive sensor using single-capacitance measurement is used, then the configuration is simple, but it is susceptible to environmental influences such as temperature, moisture, and magnetic fields causing erroneous operations
Solution Approach 1:
The patent combines self-capacitance measurement and mutual-capacitance measurement into a single capacitive touch sensing system. The sensing electrode and transmission electrode work together to provide both measurement modes, allowing the system to distinguish between environmental changes and actual touch events by comparing capacitance variations from both measurement types
Solution Approach 2:
The capacitive touch sensing system performs multiple functions: it detects touch events, distinguishes between environmental changes and actual touches, and provides reliable operation across different conditions. The same electrode structure serves both self-capacitance and mutual-capacitance measurement purposes, making the system multi-functional without requiring separate dedicated components for each function
3Measurement precision
If conventional baseline updating is used where the baseline does not reflect the value obtained at the sensor electrode, then the reference is stable, but it fails to accurately detect touch events when environmental conditions change
Solution Approach 1:
The patent implements a feedback mechanism where the baseline (reference value) is continuously updated based on the capacitance values obtained from the sensing electrode. The control module compares the current capacitance value with the baseline and updates the baseline when no touch is detected, allowing the reference to adapt to environmental changes while maintaining stability through controlled updates rather than continuous changes
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 capacitive switch device achieves precise touch detection by using combined-capacitance measurement, reducing erroneous operations and extending the device's lifespan by minimizing environmental impact and component wear, while also simplifying the configuration and reducing assembly time compared to mechanical switches.
Implementation Method 1
A capacitance value obtained at a sensor electrode varies and a reference value (i.e., baseline) moving along with the variation in the obtained capacitance value is set. When a difference between the capacitance value obtained at the sensor electrode and the reference value (i.e., baseline) exceeds a specific threshold value, it is determined that the human body is touched.
Implementation Method 2
A capacitive touch sensing method can be typically divided into a self-capacitance type and a mutual-capacitance type.
Data Source
AI summary
The present invention provides a capacitive switch device comprising: a touch sensing unit (100) including a sensing electrode (110) and a transmission electrode (120), which are disposed on a substrate (2); and a touch control module (200) disposed on a substrate (2), and configured to confirm a manipulator's contact manipulation state based on a sensing signal from the touch sensing unit (100) and output a touch output signal, wherein the transmission electrode (120) outputs a transmission signal in response to a transmission control signal from the touch control module (200), and the sensing electrode (110) detects a signal in response to a sensing control signal from the touch control module (200) for application to the touch control module (200), and wherein the touch control module (200) activates the sensing electrode (110) and the transmission electrode (120) according to a preset mode, and a method for controlling the same.