Self-Capacitance Touch Display Panel with Uniform Common Electrode
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Solution Overview
Problem
Conventional self-capacitance touch display panels experience image flicker and non-uniform display due to varying resistances in block-shaped electrodes, leading to different voltages across liquid crystal molecules in display units.
Innovation Solution
A touch display panel design featuring a common electrode layer as a single piece with a separate touch electrode layer comprising metal grid electrodes, where touch electrode wires are electrically connected to touch electrodes, ensuring uniform voltage across display units and reducing resistance for improved sensitivity and light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the common electrode is divided into multiple block-shaped electrodes driven in time-division manner, then the display panel thickness is reduced and production efficiency is improved, but different resistances of block-shaped electrodes cause different voltages across liquid crystal molecules, resulting in image flicker and non-uniform display
Solution Approach 1:
The touch electrode layer is segmented into multiple independent touch electrodes that can be driven in time-division manner, while the common electrode layer remains as a single continuous electrode. This segmentation allows the touch function to be divided into manageable blocks without compromising the uniformity of the common voltage potential across the entire display panel.
Solution Approach 2:
The patent extracts the touch electrode function from the common electrode by creating a separate touch electrode layer. This allows the common electrode to serve purely as a reference potential without the resistance variations that would occur if it were divided into blocks, thereby eliminating image flicker while maintaining the thin-profile benefit of time-division driving.
2Ease of manufacture
If block-shaped electrodes are used in the common electrode layer, then production cost is lowered, but voltage differences across liquid crystal molecules result in image flicker
Solution Approach 1:
The patent resolves the contradiction by moving the touch electrode functionality to a different dimensional layer - the touch electrode layer above the common electrode layer. This allows the common electrode to remain as a single continuous structure (avoiding resistance variations and flicker) while the touch electrodes in the upper layer can be segmented into blocks for cost-effective manufacturing and time-division driving.
3Reliability
If touch electrodes are made with metal grid structure, then resistance is reduced and touch sensitivity is improved, but light transmittance may be affected
Solution Approach 1:
The metal grid electrodes are strategically positioned and designed with optimized grid patterns where the conductor density is adjusted locally. The grid structure provides sufficient conductivity for touch sensitivity while maintaining adequate light transmission areas, achieving a balance between electrical performance and optical properties in different regions of the electrode.
Data Source
AI summary
A touch display panel and a display apparatus are provided. The touch display panel includes: a first substrate, a second substrate, a common electrode layer, a touch electrode layer and a touch electrode wire layer. The common electrode layer is an entire piece of electrode; thus, respective display units may be ensured to have the same common voltage during a display driving, thereby solving the conventional problem of image flicker and non-uniform display of the display panel due to different common voltages in the respective display units caused by different resistances of the block-shaped electrodes in the common electrode layer. Moreover, the touch electrodes in the touch electrode layer are metal grid electrodes. Hence, the resistances of the touch electrodes are reduced and a touch sensitivity of the touch display panel is improved, while a high light transmittance of the touch display panel is ensured.