Touch Sensor Electrode Structure for On-Cell Ripple Noise Rejection
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Solution Overview
Problem
Existing touch sensors face reduced sensitivity due to noise interference from display panels, particularly in on-cell type display devices where electrodes are directly formed on the substrate, leading to parasitic capacitance and ripple in sensing signals.
Innovation Solution
The touch sensor design incorporates additional third electrodes that extend in the same direction as first electrodes, separated by insulating layers, and connected to signal receivers through specific wiring lines, allowing for noise cancellation and improved signal-to-noise ratio by buffering and outputting noise signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrodes are directly formed on the substrate in on-cell type display devices, then device integration is improved, but noise interference and parasitic capacitance increase
Solution Approach 1:
The patent introduces a third electrode as an intermediary element between the first electrode and the substrate. This third electrode is separated from the first electrode by an insulating layer, acting as a mediator that buffers the harmful electrical noise and parasitic capacitance while maintaining the integrated on-cell structure. The third electrode receives noise signals that are then processed by signal receivers to cancel out the interference.
2Measurement precision
If additional third electrodes are added for noise cancellation, then sensitivity is improved, but device complexity increases
Solution Approach 1:
The third electrode serves multiple functions simultaneously: it acts as a noise signal source for the signal receivers, provides additional sensing capability, and maintains electrical isolation from the first electrode through the insulating layer. This multi-functionality allows the additional electrode structure to improve sensitivity without proportionally increasing overall device complexity.
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 configuration enhances the sensitivity of touch sensors by reducing noise interference and improving the signal-to-noise ratio, resulting in a touch sensor with high sensitivity for display devices.
Implementation Method 1
each of the signal receivers includes first and second input terminals connected to a pair of first and third electrodes corresponding to each other, respectively, and outputs a signal corresponding to a voltage difference between the first and second input terminals
Implementation Method 2
a plurality of third electrodes including electrode portions disposed in the first electrodes, respectively, being separated from the first electrodes
Data Source
AI summary
A touch sensor including a substrate including an active area and a non-active area, a plurality of first electrodes extending in first direction on the active area, a plurality of second electrodes extending in a second direction crossing the first direction on the active area, a plurality of third electrodes including electrode portions disposed in the first electrodes, respectively, being separated from the first electrodes, and extending in the first direction on the active area, and a sensing circuit including a plurality of signal receivers receiving sensing signals from the first electrodes, respectively, in which each of the signal receivers includes first and second input terminals connected to a pair of first and third electrodes corresponding to each other, respectively, and outputs a signal corresponding to a voltage difference between the first and second input terminals.