In-Cell Touch Electrode Edge Protrusions for RC Loading
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Solution Overview
Problem
In-cell touch display devices face challenges in reducing the difference in RC loading between the edges and interior portions of touch electrodes, leading to varying signal transmission characteristics that complicate processing.
Innovation Solution
The design includes a substrate with scan lines, data lines, thin film transistors, pixel electrodes, touch electrodes, and touch signal lines, where the touch electrodes have protruding portions at the edges to match overlapping areas with scan lines, and dummy signal lines are arranged to reduce capacitive loading differences, allowing for better signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If touch electrodes are separated and arranged like a checker board, then the touch display device can be integrated into the display panel to minimize volume, but the overlapping area of touch electrodes with conductive lines varies between edge and interior portions, causing different RC loadings
Solution Approach 1:
The patent applies local quality by making the touch electrodes have different shapes at different locations. Specifically, touch electrodes at edge positions are designed with extended portions that protrude toward adjacent touch electrodes, while interior touch electrodes maintain standard shapes. This local modification equalizes the overlapping area with conductive lines across all touch electrodes, ensuring uniform RC loading despite the integrated in-cell structure.
2Ease of manufacture
If touch electrodes have uniform shape and size, then manufacturing is simplified, but the overlapping area with conductive lines differs between edge and interior portions, causing varying RC loadings
Solution Approach 1:
The patent implements local quality by introducing position-dependent variations in touch electrode geometry. Edge touch electrodes include extended portions that protrude toward adjacent electrodes, while interior electrodes maintain uniform shapes. This localized modification compensates for the varying overlapping areas with conductive lines, equalizing RC loading across all positions while maintaining manufacturability through a systematic design rule.
3Reliability
If RC loading is equalized across all touch electrodes, then signal transmission consistency is improved, but the touch electrode structure becomes more complex with extended portions
Solution Approach 1:
The patent resolves this contradiction by applying local quality in a targeted and systematic manner. Only edge touch electrodes receive the extended portion modification, while interior electrodes remain simple and uniform. This selective approach equalizes RC loading across all touch electrodes, improving signal transmission consistency while minimizing the increase in structural complexity to only what is necessary at boundary positions.
Data Source
AI summary
A touch display device includes a substrate, a plurality of scan lines, a plurality of thin film transistors and a plurality of touch electrodes. The scan lines and the thin film transistors are disposed on the substrate, and each of the thin film transistors is electrically connected to a corresponding scan line of the scan lines. The scan lines include a first scan line. The touch electrodes are disposed on the substrate, the touch electrodes include a first touch electrode and a second touch electrode, the first touch electrode is adjacent to the second touch electrode, the first scan line is disposed between the first touch electrode and the second touch electrode, and the first scan line is partially covered by the first touch electrode.