Touch Sensor Sensing Line Layout for Uniform Resistance
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Solution Overview
Problem
In touch sensors, differences in line lengths of sensing lines lead to variations in line resistance, which distort touch event signals and hinder accurate detection of touch events.
Innovation Solution
The touch sensor employs a multilayer structure for sensing lines with varying widths, connected via contact holes, to maintain uniform line resistance across the sensor, ensuring consistent touch recognition rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sensing lines have the same line width, then the manufacturing process is simple, but line resistance varies due to different line lengths
Solution Approach 1:
The patent applies local quality by making each sensing line have a different width according to its specific length. Longer sensing lines are made wider to compensate for their increased resistance, while shorter lines are made narrower. This localized adjustment of line width ensures that all sensing lines have substantially equal resistance values, resolving the contradiction between manufacturing simplicity and resistance uniformity.
Solution Approach 2:
The patent changes the physical parameter of line width to compensate for variations in line length. By adjusting the width parameter inversely proportional to the length of each sensing line, the overall resistance (R = ρL/A) is equalized across all lines. This parameter change approach allows the system to maintain uniform electrical characteristics despite geometric variations.
2Device complexity
If line resistance varies, then the structure remains simple with uniform line widths, but signal distortion occurs affecting touch detection accuracy
Solution Approach 1:
The patent implements local quality by assigning different widths to different sensing lines based on their individual lengths and positions. Each sensing line is optimized locally to have equal resistance, preventing signal distortion during touch event detection. This localized optimization improves measurement precision without requiring complex additional structures.
3Reliability
If all sensing lines have equal resistance, then touch recognition is uniform, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses parameter changes by systematically varying line width as a function of line length. This predetermined parameter adjustment compensates for the increased manufacturing precision requirements by built-in compensation, ensuring uniform touch recognition across the entire sensing area while maintaining feasible manufacturing tolerances.
Data Source
AI summary
A touch sensor includes a substrate, an insulating layer, a sensor, and sensing lines. The substrate includes: a sensing region, and a peripheral region at a periphery of the sensing region. The insulating layer is on the substrate. The insulating layer includes contact holes. The sensor is on the substrate and overlaps the sensing region. The sensing lines are on the substrate and overlap the peripheral region. The sensing lines are connected to the sensor. Each of the sensing lines is formed as a multilayer structure. The multilayer structure includes a first electrically conductive layer on the substrate, and a second electrically conductive layer connected to the first electrically conductive layer via a contact hole among the contact holes. Widths of the sensing lines are different from one another.