On-Cell Touch Electrode Layout for Uniform Display Overcoating
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Solution Overview
Problem
In display devices with on-cell type touch sensors, the mesh-like or net-like sensor electrodes surrounding the sub-pixels face challenges in uniform coverage due to the stepped patterns, leading to incomplete coverage by the organic resin overcoat layer, which affects the reliability and appearance of the display.
Innovation Solution
The display device incorporates a linear sensor electrode with cut-off portions at the boundaries of sub-pixels, allowing for improved coverage by the overcoat layer and enhancing the uniformity and reliability of the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mesh-shaped sensor electrodes are used to reduce resistance, then electrical conductivity is improved, but the overcoat layer cannot be uniformly applied due to steps formed by the electrode pattern
Solution Approach 1:
The sensor electrode is divided into multiple segments along its length, with cut-off portions at sub-pixel boundaries. This segmentation allows the overcoat layer to be applied uniformly across each segment while maintaining the conductive function of the electrode material.
Solution Approach 2:
The electrode structure is modified locally at sub-pixel boundaries by introducing cut-off portions. This local modification eliminates the step formation problem at critical locations while preserving the mesh-shaped electrode's overall conductive properties in the display regions.
2Reliability
If mesh-shaped sensor electrodes surround the outline of sub-pixels, then resistance is reduced, but non-uniform coverage of the overcoat layer affects appearance
Solution Approach 1:
The continuous mesh electrode is segmented at sub-pixel boundaries, creating discrete electrode portions within each sub-pixel region. This segmentation eliminates the visual disruption caused by the overcoat layer's non-uniform application while maintaining electrical connectivity through the segmented structure.
Solution Approach 2:
The electrode configuration is optimized locally within each sub-pixel region, ensuring that the overcoat layer applies uniformly over the electrode structure in visible areas, thereby improving appearance consistency while maintaining the electrode's resistance-reducing function.
3Reliability
If continuous sensor electrodes are used to ensure electrical connectivity, then conductivity is maintained, but the overcoat layer application becomes non-uniform due to step formation
Solution Approach 1:
The electrode is segmented into discrete portions at sub-pixel boundaries while maintaining electrical connectivity through the segmented structure. This segmentation removes the step formation that causes non-uniform overcoat application, allowing the overcoat to be applied smoothly across the entire surface.
Solution Approach 2:
The cut-off portions act as intermediaries between adjacent sub-pixel electrode regions, allowing the overcoat layer to transition smoothly across sub-pixel boundaries while the electrode portions maintain electrical connectivity within each sub-pixel region.
Data Source
AI summary
A display device includes at least one pixel including a plurality of sub-pixels, and a linear sensor electrode extending along a boundary of the plurality of sub-pixels and surrounding a periphery of the at least one pixel. The sensor electrode has at least one cut-off portion at the boundary of the plurality of sub-pixels. The sensor electrode can include a first sensor electrode extending along the boundary of a plurality of sub-pixels and a second sensor electrode that surrounds the periphery of at least one pixel continuous from the first sensor electrode, and the cut-off portion can be located at the boundary of the first sensor electrode with the second sensor electrode.