Sensor Electrode Guarding for Display Panel Interference Reduction
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Solution Overview
Problem
In input devices, sensor electrodes can interfere with display electrodes, causing display artifacts due to capacitive coupling, which existing technologies have not effectively mitigated.
Innovation Solution
The solution involves spatially separating sensor electrodes driven for capacitive sensing from gate lines selected for display updating by driving a third portion of sensor electrodes with a reference signal, while driving a second portion with a guarding signal that shares characteristics with the sensing signal, thereby reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sensor electrodes are driven for capacitive sensing during display updating, then input sensing functionality is enabled, but display artifacts occur due to interference between sensor and display electrodes
Solution Approach 1:
The sensor electrode array is divided into multiple portions (first portion, second portion, third portion) that are driven with different signals (sensing signal, guarding signal, reference signal) during different time periods. This segmentation allows simultaneous input sensing and display updating by isolating interference-prone operations to specific portions and time slots, thereby enabling input sensing functionality while minimizing display artifacts.
Solution Approach 2:
The patent implements periodic sensing frames with distinct time periods (first period, second period, third period) where different portions of sensor electrodes are activated sequentially. During the first period, the first portion performs sensing while the second and third portions are held at guarding and reference potentials respectively. This periodic activation pattern enables continuous input sensing functionality while the temporal separation reduces capacitive coupling interference that causes display artifacts.
2Object-affected harmful factors
If sensor electrodes are spatially separated from display electrodes, then interference is reduced, but device area increases
Solution Approach 1:
Instead of spatially separating sensor and display electrodes in the planar domain, the patent separates their operational timelines into different time periods within the same physical space. The sensor electrodes are driven with sensing, guarding, and reference signals during different periods of the sensing frame, effectively moving the separation from spatial dimension to temporal dimension. This allows overlapping sensor and display electrodes in the same area without increased device footprint, while still reducing interference through temporal isolation.
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 effectively minimizes interference between sensor and display electrodes, reducing display artifacts and improving the accuracy of input sensing without compromising display updating.
Implementation Method 1
The sensor circuitry is configured to operate sensor electrodes for input sensing during a first sensing frame
Implementation Method 2
The guarding signal and the sensing signal have at least one characteristic in common selected from the group consisting of amplitude, phase and frequency
Data Source
AI summary
A processing system for an input device comprises sensor circuitry. The sensor circuitry is configured to operate sensor electrodes for input sensing during a first sensing frame. During a first period of the first sensing frame the sensor circuitry is configured to drive a first portion of the sensor electrodes with a sensing signal, drive a second portion of the sensor electrodes with a guarding signal, and drive a third portion of the sensor electrodes with a reference signal. The guarding signal and the sensing signal have at least one characteristic in common selected from the group consisting of amplitude, phase and frequency. The third portion of the sensor electrodes overlaps a first gate line of a display panel selected for updating during the first period.