Capacitance Sensor Electrode Failure Detection Using Multi-Function Switches
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Solution Overview
Problem
Existing capacitance sensors face challenges in accurately detecting the proximity of a detection object due to issues with short-circuited or open states of detection electrodes, leading to increased manufacturing costs and complex failure diagnosis procedures.
Innovation Solution
A capacitance sensor configuration that uses a capacitor with a preset potential and multiple switches to determine electrode failures based on potential differences, allowing for failure detection without additional components, thereby reducing costs and simplifying the diagnosis process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional switches and capacitors are added to determine electrode failures, then failure detection accuracy is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent makes existing switches (first through fifth switches) perform dual functions: they control detection electrode connections during normal operation and simultaneously serve as failure determination switches. By configuring these switches to connect determination electrodes to different potentials (ground or power supply) based on operation mode, the system achieves failure detection without adding dedicated switches, thus resolving the contradiction between reliability and device complexity
Solution Approach 2:
The system uses its own existing components (switches and capacitor) to perform failure determination. The first detection electrode and capacitor form a determination circuit that self-diagnoses failures by monitoring potential differences when switches are configured in specific states, eliminating the need for external diagnostic equipment or additional dedicated failure detection components
2Ease of repair
If additional components are added for failure diagnosis, then diagnostic capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent configures existing switches to serve dual purposes: controlling detection electrode connections during normal sensing operation and enabling failure determination by connecting determination electrodes to different potentials. This multi-functionality approach allows the system to achieve comprehensive failure diagnosis capability without adding dedicated diagnostic components, thereby improving ease of repair while keeping manufacturing costs low
Solution Approach 2:
The patent merges the normal operation control functions with failure determination functions into a single integrated system. The same switches and capacitor used for detecting object proximity are also used for determining electrode failures, combining multiple functions into existing components rather than adding separate diagnostic subsystems
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
Enables accurate failure determination and proximity detection of detection objects without the need for new components, reducing manufacturing costs and improving convenience in failure diagnosis.
Implementation Method 1
a capacitor whose one terminal is applied with a preset first potential
Implementation Method 2
a first switch provided over the one terminal and the other terminal of the capacitor; a second switch whose one terminal is connected to the other terminal of the capacitor
Data Source
AI summary
A capacitance sensor detects proximity of a detection object based on changes in capacitances between the detection object and a first detection electrode and between the detection object and a second detection electrode. The capacitance sensor includes: a capacitor applied with a first potential; a first switch provided over terminals of the capacitor; a second switch connected to the capacitor; a third switch connected to the second switch and the first detection electrode, and applied with a second potential; a fourth switch connected to the capacitor; a fifth switch connectable to the second detection electrode and connected to the fourth switch, and applied with the second potential; and a determination unit determining a failure of the first detection electrode based on a potential difference between a potential of the terminal of the capacitor and a reference potential.