Partial Guarding for Sensor Electrodes to Reduce Capacitive Coupling
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Solution Overview
Problem
In input devices with sensor electrodes proximate to display devices, capacitive coupling between sensor and display electrodes increases power requirements for capacitive sensing, leading to inefficiencies and interference.
Innovation Solution
A method where a first portion of sensor electrodes is driven with a sensing signal, a second portion with a guarding signal having common characteristics, and a third portion is either driven with a DC signal or electrically floated, to reduce capacitive coupling and mitigate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor electrodes are driven with sensing signals for capacitive sensing, then detection capability is improved, but power consumption increases due to capacitive coupling with display electrodes
Solution Approach 1:
The sensor electrode structure is segmented into multiple portions (first portion, second portion, third portion) with different electrical configurations. The first portion is driven with sensing signals for detection, while the second and third portions are configured to reduce capacitive coupling with display electrodes, thereby reducing overall power consumption while maintaining detection capability in the first portion
Solution Approach 2:
Different portions of the sensor electrodes are assigned different electrical characteristics and functions. The first portion has sensing capability with full drive strength, while the second and third portions have reduced or modified drive characteristics to minimize capacitive coupling effects, creating local quality variations that optimize both detection and power efficiency
2Device complexity
If sensor electrodes are positioned proximate to display electrodes for integrated design, then device integration is improved, but interference from display electrodes increases
Solution Approach 1:
The sensor electrode array is divided into distinct portions with different configurations. The second portion is specifically configured to reduce capacitive coupling with display electrodes, creating a segmented approach where different regions handle different functions (detection vs. interference reduction)
Solution Approach 2:
The second portion of sensor electrodes acts as an intermediary element between the first sensing portion and the display electrodes. By configuring this intermediate portion to reduce capacitive coupling, it mediates the interaction between the sensing system and display electrodes, reducing interference while maintaining integration
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 reduces the power required to operate sensor electrodes for capacitive sensing while minimizing interference from display electrodes, enhancing the detection of input objects and reducing power consumption.
Implementation Method 1
capacitive sensing
Implementation Method 2
changes in capacitance between the sensor electrodes and the display electrodes
Data Source
AI summary
A system and method for operating sensor electrodes comprises driving, during a first period, a first portion of the sensor electrodes with a sensing signal. A second portion of the sensor electrodes is driven with a guarding signal during the first period. The second portion is adjacent to the first portion. The guarding signal and the sensing signal have at least one characteristic in common that is selected from a group consisting of amplitude, phase, and frequency. A third portion of the sensor electrodes is electrically floated or driven with a direct current signal during the first period. The third portion is adjacent to the second portion but not adjacent to the first portion.