In-Cell Touch Electrode Floating Parts for Parasitic Capacitance
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Solution Overview
Problem
In-cell touch panels face reduced touch sensitivity and malfunction due to increased parasitic capacitance between electrodes and a user's finger, caused by decreased thickness, leading to unintended touch signals and retransmission.
Innovation Solution
The formation of floating parts in the first and second touch electrodes, dividing the first touch electrode into sub-electrodes, and increasing the number of intersection areas between the electrodes to minimize parasitic capacitance and maintain mutual capacitance, while using the same material for floating and detection parts to prevent visibility reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the touch panel is decreased, then the visibility and flexibility of the display device are improved, but the parasitic capacitance between the touch electrodes and the user's finger increases, causing retransmission and touch sensitivity degradation
Solution Approach 1:
The first touch electrode is divided into multiple first sub-electrodes, and the second touch electrode is divided into multiple second sub-electrodes. This segmentation increases the number of intersection areas between electrodes, thereby compensating for the reduced mutual capacitance caused by the thinner panel structure while maintaining touch sensitivity.
Solution Approach 2:
Floating parts are formed at specific locations (intersection areas) of the touch electrodes rather than uniformly across the entire electrode structure. This localized approach minimizes parasitic capacitance at critical points where retransmission occurs, while preserving the overall touch detection functionality.
2Length of moving object
If the thickness of the cover film is decreased to reduce overall panel thickness, then the display device becomes thinner, but the gap between the touch electrodes and the user's finger decreases, leading to increased parasitic capacitance and unintended touch signals
Solution Approach 1:
Floating parts are extracted from the continuous touch electrode structure at intersection areas. These floating parts are electrically isolated from the main electrode conductors, effectively removing the source of parasitic capacitance at critical intersection points where retransmission would otherwise occur.
Solution Approach 2:
The floating parts are strategically positioned at intersection areas of the touch electrodes, applying the local quality principle to address parasitic capacitance specifically at locations where multiple electrodes cross, rather than uniformly across the entire electrode structure.
3Object-generated harmful factors
If floating parts are formed in the touch electrodes to minimize parasitic capacitance, then retransmission is reduced, but the mutual capacitance decreases, requiring compensation through increased number of intersection areas
Solution Approach 1:
By segmenting the touch electrodes into multiple sub-electrodes, the number of intersection areas is increased. This segmentation compensates for the reduced mutual capacitance caused by floating parts, as each additional intersection area contributes to the overall capacitive coupling between the first and second touch electrodes.
Solution Approach 2:
Multiple intersection areas are effectively combined to achieve the required total mutual capacitance. While individual intersection areas may have reduced capacitance due to floating parts, the cumulative effect of multiple intersections maintains or enhances the overall touch detection capability.
4Quantity of substance
If the first and second touch electrodes are divided into sub-electrodes to increase intersection areas, then mutual capacitance is maintained, but the device complexity increases
Solution Approach 1:
The touch electrodes are segmented into sub-electrodes that can be implemented using standard thin-film fabrication processes. The segmentation pattern follows regular geometric arrangements that simplify manufacturing while achieving the required number of intersection areas for adequate mutual capacitance.
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 parasitic capacitance, minimizes retransmission, and maintains touch sensitivity even at reduced thickness, allowing for thinner and more flexible touch panels without compromising visibility.
Implementation Method 1
a parasitic capacitance between the first and second touch electrodes and the user's finger may be increased
Implementation Method 2
the touch panel can detect a touch input by detecting a change in a mutual capacitance between the first and second touch electrodes
Data Source
AI summary
Provided is a touch panel-integrated organic light emitting display device. The touch panel-integrated organic light emitting display device includes an upper substrate, a lower substrate and a touch panel positioned between the upper substrate and the lower substrate. The touch panel includes an array of first touch electrodes connected in a first direction under the upper substrate, an array of second touch electrodes, in a same plane as the first touch electrodes, connected in a second direction perpendicular to the first direction under the upper substrate, a plurality of connection electrodes connecting the second touch electrodes in the second direction, and at least one of the first and second touch electrodes includes a touch detection part and a floating part electrically isolated from the touch detection part.