Capacitance Sensing via Charge Counting to Eliminate Noise
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Solution Overview
Problem
Existing touch sensing apparatuses using electrostatic capacitive sensing technology face challenges in accurately sensing touch inputs due to vulnerability to CS noise, RS noise, and radio noise, leading to errors in determining touch, and current methods to mitigate these issues increase costs and complexity.
Innovation Solution
A method and apparatus that sense electrostatic capacity changes by charging a reference capacitor, sharing and discharging charges with a capacitor to be measured, and counting the number of sharing and discharging times to determine capacity changes, eliminating the need for a sensing frequency and reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensing frequency method is used to sense touch in a touch pad, then the touch can be detected, but the sensing frequency becomes vulnerable to CS noise, RS noise, and radio noise causing errors in touch determination
Solution Approach 1:
The patent extracts and eliminates the sensing frequency component from the touch detection system. Instead of using a sensing frequency to detect touch, the system uses a capacitive sensing method that measures changes in capacitance without requiring a sensing frequency, thereby removing the source of noise vulnerability while maintaining touch detection capability
Solution Approach 2:
The patent introduces an intermediary measurement approach by using a test signal with a fixed frequency (different from sensing frequency) to indirectly measure capacitance changes. This intermediary signal allows the system to detect touch through capacitance variation without directly using the vulnerable sensing frequency, thus mediating between the touch input and the measurement system
2Reliability
If multiple frequencies are used in the sensing section to avoid noise, then noise interference is reduced, but the cost and structure of the touch sensing apparatus become complicated
Solution Approach 1:
The patent removes the complex multi-frequency sensing section from the system. Instead of using multiple frequencies to combat noise, the system employs a single fixed-frequency test signal combined with a capacitor-based measurement approach, significantly simplifying the sensing section structure while maintaining noise resistance through the fundamental capacitive sensing principle
Solution Approach 2:
The patent changes the measurement parameter from frequency-based detection to capacitance-based detection. By measuring changes in capacitance using a fixed-frequency test signal, the system achieves noise resistance without requiring multiple frequencies, thus changing the fundamental parameter used for sensing and simplifying the overall device structure
3Reliability
If sensing algorithms are improved to avoid noise, then touch detection accuracy increases, but the development time and complexity increase significantly
Solution Approach 1:
The patent extracts the noise vulnerability from the sensing algorithm by eliminating the sensing frequency component entirely. This fundamental change allows touch detection to be achieved through simple capacitance measurement without requiring complex noise-filtering algorithms, thereby reducing development time while maintaining accuracy
Solution Approach 2:
The patent substitutes complex algorithmic processing with a simpler physical measurement approach. Instead of using sophisticated sensing algorithms to filter noise, the system uses a fundamental capacitive sensing mechanism that inherently rejects noise, replacing software complexity with a simpler physical principle
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 approach allows for accurate sensing of touch and other environmental changes without using sensing frequencies, reducing noise interference and simplifying the apparatus structure, thereby improving reliability and cost-effectiveness.
Implementation Method 1
sharing a part of charges of the reference capacitor with the capacitor to be measured
Implementation Method 2
discharging at least a part of the charges shared with the capacitor to be measured
Data Source
AI summary
Disclosed are an electrostatic capacity change sensing method and apparatus, and a recording medium in which a program executing the method is recorded, a touch sensing method and apparatus, and a recording medium in which a program executing the method is recorded. The electrostatic capacity change sensing method and apparatus are capable of sensing the change in the electrostatic capacity without using the sensing frequency. The touch sensing method and apparatus are capable of sensing touch without using the sensing frequency.