Compensation Electrode Overlap for Touch Impedance Equalization
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Solution Overview
Problem
The existing self-capacitance touch design in display panels experiences significant impedance differences between touch signal lines at the near and far ends, leading to poor touch performance, including flicker phenomena, due to resistance and capacitance loading (RC loading) issues.
Innovation Solution
The introduction of a compensation electrode layer with varying overlapping areas with touch electrodes, where the overlapping area is larger near the driving circuit and smaller further away, helps to equalize impedance across touch electrode blocks, connected via touch signal lines, thereby compensating for impedance differences and improving touch performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common electrode layer is divided into hundreds of blocks and each block is connected to the touch signal line separately, then the touch function can be realized, but the impedance difference between near-end and far-end touch signal lines becomes large, causing touch signal power to decrease from near end to far end
Solution Approach 1:
The patent applies local quality by making different parts of the touch electrode block have different properties. Specifically, the touch electrode block includes a touch electrode and a compensation electrode with different overlapping areas with the common electrode layer. The compensation electrode has a first overlapping area with the touch electrode in a first region and a second overlapping area in a second region, where the first overlapping area is different from the second overlapping area. This creates local variations in capacitance to compensate for the impedance differences caused by signal line length variations.
2Adaptability or versatility
If the touch signal line is made longer to reach far-end blocks, then all blocks can be connected, but the impedance and loading of the touch signal line increases, causing larger loading at the far end
Solution Approach 1:
The patent applies parameter changes by modifying the capacitance parameters of different regions of the touch electrode block. The compensation electrode is designed with varying overlapping areas with the common electrode layer, creating region-specific capacitance values. This changes the electrical parameters (capacitance) to compensate for the effects of varying signal line lengths, thereby equalizing the overall impedance across all touch blocks regardless of their position.
3Device complexity
If the overlapping area between touch electrode and compensation electrode is uniform across all blocks, then the structure is simple, but the impedance difference between near-end and far-end blocks cannot be compensated
Solution Approach 1:
The patent implements local quality by creating non-uniform overlapping areas between the compensation electrode and the common electrode layer across different regions. The compensation electrode has a first overlapping area in a first region and a second overlapping area in a second region, where these areas are deliberately made different to compensate for position-dependent impedance variations. This local differentiation improves touch performance reliability without requiring complex external compensation circuits.
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 solution effectively reduces impedance differences between touch electrode blocks, enhancing touch performance by maintaining a consistent touch signal power distribution across the display panel, thereby reducing flicker and improving overall display quality.
Implementation Method 1
each of the touch electrode blocks includes a touch electrode and a compensation electrode which are disposed to be insulated from each other, and the touch signal line and the compensation electrode are disposed on a same layer; wherein the orthographic projections of the touch electrode and the compensation electrode projected on the array substrate have an overlapping area
Data Source
AI summary
The disclosure provides a display device and a display panel. The display panel includes an array substrate, a driving circuit, a touch electrode layer. Each of the touch electrode blocks includes a touch electrode and a compensation electrode which are disposed to be insulated from each other. The touch signal line and the compensation electrode are disposed on a same layer. The orthographic projections of the touch electrode and the compensation electrode projected on the array substrate have an overlapping area, and the overlapping area on the touch electrode block close to the driving circuit is larger than the overlapping area on the touch electrode block away from the driving circuit.