Capacitive Touch Device Noise Shielding via Electric Field Wall
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Solution Overview
Problem
Conventional capacitive touch devices experience cross-interference between sensor regions due to magnetic field coupling, which existing shielding solutions, such as large area grounding, fail to completely alleviate, leading to persistent noise issues.
Innovation Solution
A noise-shielded capacitive touch device design featuring extension portions on sensing lines and a smaller area shielding layer that forms an electric field wall between sensor regions, preventing magnetic field line formation and thus isolating the regions effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large area shielding layer is used to block magnetic field lines, then cross-interference between sensor regions is reduced, but device size and complexity increase
Solution Approach 1:
The shielding layer is segmented into multiple discrete shielding structures positioned at specific locations between sensor regions, rather than using a continuous large area shielding layer. This segmentation maintains interference blocking effectiveness while reducing overall shielding material usage and device complexity.
Solution Approach 2:
Shielding structures are strategically placed only at critical locations where magnetic field coupling occurs between adjacent sensor regions, rather than providing uniform shielding across the entire device. This localized approach addresses cross-interference problems at specific hotspots without requiring extensive shielding coverage.
2Object-affected harmful factors
If a large area shielding layer is used to block magnetic field lines, then cross-interference between sensor regions is reduced, but device area increases
Solution Approach 1:
The shielding layer is segmented into multiple discrete shielding structures positioned at specific locations between sensor regions, rather than using a continuous large area shielding layer. This segmentation maintains interference blocking effectiveness while reducing overall shielding material usage and device complexity.
Solution Approach 2:
Shielding structures are strategically placed only at critical locations where magnetic field coupling occurs between adjacent sensor regions, rather than providing uniform shielding across the entire device. This localized approach addresses cross-interference problems at specific hotspots without requiring extensive shielding coverage.
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
The solution effectively isolates adjacent sensor regions with a minimal shielding layer, reducing cross-interference and maintaining touch sensing functionality while minimizing device size and complexity.
Implementation Method 1
the extension portions and the shielding layer form an electric field wall to isolate the first sensor region and the second sensor region
Implementation Method 2
a magnetic field line is formed at the sensing node N99. However, because the distance between the first sensor region 11 and the second sensor region 12 is short, a magnetic field line can also be formed between the driving line DA9 of the first sensor region 11 and the sensing line SA9 of the second sensor region 12
Implementation Method 3
the charges of the driving lines DA1 ̃DA9 are capacitively coupled to the corresponding sensing lines SA1 ̃SA9 at each of the intersections (i.e., the sensing nodes N11, N12, N13. . . , N98, N99) to generate corresponding voltages sensible by the sensing lines SA1 ̃SA9
Data Source
AI summary
The present invention discloses a noise-shielded capacitive touch device, which includes a first sensor region, a second sensor region and a shielding layer. Each of the first sensor region and the second sensor region includes plural sensing lines and driving lines. The sensing lines are in parallel with each other and extend along a first direction. Each sensing line has an extension portion at its end near the other sensor region. The driving lines are in parallel with each other and extend along a second direction, wherein the second direction intersects the first direction. The extension portions and the shielding layer form an electric field wall to avoid cross interferences between the two sensor regions.