Touch Sensor Routing Lines with Uneven Surface for Bending Area
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Solution Overview
Problem
Flexible display devices experience stress and potential disconnection or cracking in the bending area due to concentrated stress, which deteriorates the reliability and stability of touch screens.
Innovation Solution
Incorporating an uneven part on the bending area of the upper substrate for the touch sensor, where routing lines have an uneven surface, reducing stress and preventing cracking or disconnection during bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If routing lines are arranged in the bending area of flexible display device, then the touch screen can be attached to flexible display panel, but stress concentration occurs causing disconnection or cracking
Solution Approach 1:
The patent applies local quality by creating an uneven surface structure specifically in the bending area where routing lines are located. The convex and concave portions are localized to the bending region, allowing this area to have different mechanical properties (stress-distributing uneven surface) compared to other flat areas of the substrate, thus resolving the contradiction between flexibility and routing line stability.
Solution Approach 2:
The patent uses curvature by forming convex and concave portions on the uneven surface. These curved geometric features help distribute stress more evenly across the routing lines in the bending area, preventing stress concentration that would occur with a flat surface, thereby maintaining routing line integrity while allowing device flexibility.
2Ease of operation
If bending area is created for flexible display, then device can be folded like paper, but stress concentrates on routing lines causing cracking
Solution Approach 1:
The uneven surface structure is applied locally only to the bending area where routing lines are present, rather than the entire substrate. This localized modification provides stress distribution benefits exactly where needed (in the folding region) without affecting other areas, enabling foldability while protecting routing lines from cracking.
Solution Approach 2:
The convex and concave portions create a curved, uneven surface topology in the bending area. This curvature distributes the mechanical stress that occurs during folding across a broader area and prevents stress concentration at specific points, thereby maintaining routing line strength while enabling the device to be folded.
3Reliability
If uneven surface with convex-concave pattern is formed on bending area, then stress is distributed and cracking is prevented, but manufacturing complexity increases
Solution Approach 1:
The uneven surface structure is applied locally only to the bending area where routing lines are present, rather than the entire substrate. This localized modification provides stress distribution benefits exactly where needed (in the folding region) without affecting other areas, enabling foldability while protecting routing lines from cracking.
Solution Approach 2:
The patent changes the surface parameter (flat to uneven) only in the specific bending area where routing lines are located. By modifying the surface topology parameter locally rather than globally, the patent achieves stress distribution and cracking prevention while minimizing the overall structural complexity and manufacturing difficulty.
Data Source
AI summary
Disclosed is a display device capable of exhibiting improved reliability and stability. The display device includes an uneven part, which is disposed on a bending area of an upper substrate, on which a touch sensor is disposed. Therefore, each of routing lines disposed on the uneven part has an uneven surface that is formed along the uneven part within the bending area. Accordingly, cracking or disconnection of the routing lines is prevented during bending of the display device, and consequently reliability and stability are improved.