Touch Sensor Sensing Lines with Varying Metal Widths
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Solution Overview
Problem
As display devices with touch sensors trend towards reducing the non-display area, the reduced space increases the likelihood of short circuits between sensing lines due to closer proximity, which existing touch sensor designs fail to adequately address.
Innovation Solution
The touch sensor design incorporates alternating first and second sensing lines with varying metal layer widths and distances, ensuring a sufficient gap between the lines to prevent short circuits while maintaining line resistance, featuring a substrate with a sensing area and peripheral area, where the sensing lines are connected to sensing electrodes through insulating layers and contact holes, allowing for adjustable metal layer widths and distances to maintain line integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the non-display area is reduced to meet miniaturization trends, then the device size is reduced, but the risk of short circuits between sensing lines increases
Solution Approach 1:
The patent applies local quality by making the sensing lines have different widths at different locations. Specifically, the sensing lines have a first width in the sensing area and a second width in the peripheral area, with the second width being greater than the first width. This local variation in width provides better spacing and insulation in the peripheral area where short circuits are more likely to occur, while maintaining compact dimensions in the sensing area.
Solution Approach 2:
The patent employs asymmetry by creating non-uniform sensing line structures through alternating wide and narrow sensing lines. The first sensing lines have different widths compared to the second sensing lines, forming an asymmetric pattern that optimizes both space utilization and short circuit prevention. This asymmetric design allows the device to achieve miniaturization while maintaining reliability through strategic spacing variations.
2Area of stationary object
If the sensing lines are made closer together to reduce device size, then the device footprint is reduced, but the line resistance control becomes more difficult
Solution Approach 1:
The patent applies local quality by varying the width of sensing lines based on their location and function. The sensing lines have different widths in different areas, allowing optimization of electrical properties in specific regions. This local variation enables precise control of line resistance even when lines are closely spaced, as the width can be adjusted to compensate for proximity effects.
Solution Approach 2:
The patent employs parameter changes by systematically varying the width parameter of sensing lines. The sensing lines alternate between first widths and second widths, creating a pattern that optimizes both spacing and electrical resistance. This parameter variation allows the design to achieve compact footprint while maintaining manufacturable line resistance characteristics through controlled geometric adjustments.
Data Source
AI summary
A touch sensor includes a substrate, sensing electrodes (SEs), and sensing lines (SLs). The substrate includes a sensing area (SA) and a peripheral area outside the SA. The SEs overlap the SA. The SLs overlap the peripheral area, are respectively connected to the SEs, and include first SLs (FSLs) alternatingly arranged with second SLs (SSLs). Each of the SLs includes: a first metal layer (FML) on the substrate; a first insulating layer (FIL) on the FML and including a first contact hole (FCH) exposing the FML; and a second metal layer (SML) on the FIL and connected to the FML through the FCH. A width of the FML of each of the FSLs is different from a width of the FML of each of the SSLs. A width of the SML of each of the FSLs is different from a width of the SML of each of the SSLs.