Capacitive Touch Screen Electrode Gap Design for Sensitivity Consistency
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Solution Overview
Problem
Capacitive touch screens face challenges in maintaining consistent touch performance across regions due to the introduction of the ink-based black matrix (BM) region, which affects electrode characteristics and etching rates, leading to sensitivity differences and processing difficulties.
Innovation Solution
A capacitive touch screen design with a touch electrode layer extending over a decorative layer, featuring wider gaps between touch patterns in the ink region compared to the visible area, and a corresponding mask device with shielding patterns, allowing for adjusted etching rates and reduced impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the electrode pattern region extends to the ink BM region to meet edge touch performance requirements, then the touch coverage is improved, but the touch sensitivity consistency deteriorates due to different capacitance characteristics between BM and VA regions
Solution Approach 1:
The patent applies different gap widths between touch patterns in different regions: a first gap width in the visible area (VA) region and a second gap width in the ink black matrix (BM) region. This local differentiation allows the electrode structure to adapt to different dielectric environments, maintaining consistent touch sensitivity across regions while extending coverage to the edge area.
2Area of stationary object
If the electrode patterns are manufactured on both BM and VA regions, then the touch coverage is improved, but the manufacturing precision deteriorates due to different etching rates in different regions
Solution Approach 1:
The patent specifies different gap widths for etching in different regions: a first gap width for VA regions and a second gap width for BM regions. This local differentiation compensates for the different etching rates caused by different dielectric substances, allowing precise control of electrode dimensions across the entire substrate including edge areas.
Data Source
AI summary
A capacitive touch screen includes a substrate (01), a touch electrode layer (02), and a decorative layer (03). The substrate (01) has a first surface, the first surface includes a first region (011) and a second region (012), and the second region (012) is positioned on one side of the first region (011), the decorative layer (03) is formed on the second region (012). The touch electrode layer (02) is formed on the first region (011) of the first surface, and the touch electrode layer (02) extends above the decorative layer (03) on the second region (012), the touch electrode layer (02) includes a plurality of touch patterns, two adjacent touch patterns on the first region (011) are provided with a first gap (04) therebetween, two adjacent touch patterns on the second region (012) are provided with a second gap (05) therebetween, and a width of the second gap (05) is greater than a width of the first gap (04).