Differential Capacitive Touch Sensing for Display Noise Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing capacitive sensors in portable devices are prone to damage from overuse and suffer from noise interference, leading to inaccurate input detection, especially when used in environments with changing noise levels like displays.
Innovation Solution
A capacitive sensor design featuring detecting plates and reference plates electrically coupled to separate wires, where signal differences between the wires are used to detect touches or approaches, allowing for simultaneous multiple touch detection with noise resistance, and optionally covered with an insulating layer for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitive sensors are used instead of mechanical keys, then durability is improved, but noise resistance deteriorates
Solution Approach 1:
The sensor is divided into multiple detecting plates arranged in a matrix, each independently capable of detecting touches. This segmentation allows the system to process signals from multiple zones simultaneously while maintaining durability and improving noise resistance through comparative analysis.
Solution Approach 2:
Reference plates are introduced as intermediary elements that provide a baseline signal for comparison. By comparing the signal from each detecting plate against its corresponding reference plate, the system can distinguish between noise and actual touch inputs, thereby improving noise resistance while maintaining the durability benefits of capacitive sensing.
2Reliability
If traditional capacitive sensors are used, then durability is improved, but measurement precision deteriorates due to noise
Solution Approach 1:
Reference plates serve as intermediary elements providing a baseline signal that represents the noise environment. By comparing detecting plate signals against reference plate signals, the system can filter out noise and accurately determine whether a touch has occurred, thereby improving measurement precision while maintaining durability.
Solution Approach 2:
The patent replaces traditional single-plate capacitive sensing with a differential measurement system using detecting and reference plates. This substitution transforms the measurement approach from absolute capacitance change detection to differential comparison, eliminating mechanical wear while improving detection accuracy through noise cancellation.
3Ease of operation
If mechanical keys are used, then ease of operation is maintained, but reliability deteriorates due to damage from overuse
Solution Approach 1:
The patent replaces mechanical key structures with capacitive sensing plates that detect touches through electrical field changes rather than physical contact. This substitution eliminates mechanical wear and damage from overuse while maintaining ease of operation, as users can still interact with the interface through natural touching motions.
Solution Approach 2:
The capacitive sensing plates are implemented as thin, flexible conductive layers that can be integrated into the device surface. This allows the interface to maintain a smooth, touch-friendly surface while providing durable, wear-resistant sensing capability that responds to user input without mechanical degradation.
4Adaptability or versatility
If capacitive sensors are placed in front of displays, then functionality is improved, but noise resistance deteriorates due to display-generated noise
Solution Approach 1:
Reference plates positioned near detecting plates serve as intermediaries that capture display-generated noise. By comparing the signal from each detecting plate against its corresponding reference plate, the system can subtract the display noise component and accurately detect user touches, thereby maintaining functionality in front of displays while improving noise resistance.
Solution Approach 2:
The patent implements local reference plates positioned adjacent to each detecting plate, creating localized noise cancellation zones. This local quality approach ensures that each detecting-reference plate pair can independently compensate for display noise in its specific region, maintaining high functionality and accuracy across the entire sensor array despite display-generated interference.
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 enables reliable detection of single or multiple touches with high noise resistance, reducing the risk of damage and improving accuracy in noisy environments, such as those with displays.
Implementation Method 1
When an electrical signal is provided to the first wire and each second wire, one or more detecting plates touched or approached can be detected simultaneously based on the signal difference between each second wire and the first wire
Data Source
AI summary
The present invention provides a capacitive controller for detecting at least one detecting plate and at least one reference plate surrounding each detecting plate. All of the reference plates are electrically coupled to the same first wire, and each reference plate is electrically coupled to a second wire. When an electrical signal is provided to the first wire and each second wire, one or more detecting plates touched or approached can be detected simultaneously based on the signal difference between each second wire and the first wire.