Flexible Display Substrate Crack Detection Across Drive And Touch Layers
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Solution Overview
Problem
Existing flexible display apparatuses using OLEDs face issues with cracks that can lead to water vapor penetration, affecting wiring and circuit performance, and current crack detection methods in FMLOC technology result in short circuits due to over-etching of the Touch Dielectric Layer, impairing crack detection functionality.
Innovation Solution
A display substrate design with first and second crack detection lines, including lead segments and vias, that surround the display region, allowing for separate detection of cracks in the drive circuit and touch structure layers, and a specific via and boundary configuration to prevent short circuits during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Touch Dielectric Layer is etched during crack detection, then crack detection can be performed, but over-etching causes short circuits between detection lines
Solution Approach 1:
The crack detection line is segmented into multiple sections (first detection line in drive circuit layer, second detection line in touch structure layer) that are spatially separated by the via structure. This segmentation allows independent detection of cracks in different layers without electrical interference, resolving the short circuit issue while maintaining detection capability.
Solution Approach 2:
The via structure acts as an intermediary element that connects the first and second detection lines at specific locations. By positioning vias at controlled intervals and depths, the structure enables electrical connection where needed for detection while preventing continuous contact that would cause short circuits, thus mediating between detection requirements and electrical isolation needs.
2Device complexity
If a single crack detection line is used in existing FMLOC technology, then the structure is simple, but it cannot distinguish between cracks in drive circuit layer and touch structure layer
Solution Approach 1:
The unified crack detection function is segmented into two separate detection lines: one embedded in the drive circuit layer and another in the touch structure layer. This segmentation enables independent detection and precise identification of crack locations in each layer, improving measurement precision while the overall design remains integrated and manageable.
Solution Approach 2:
The detection system transitions from a single-plane detection approach to a multi-layered detection architecture. By distributing detection lines across different vertical layers (drive circuit layer and touch structure layer), the system gains dimensional separation that enables precise crack location identification without requiring complex single-plane routing.
3Adaptability or versatility
If crack detection lines are placed in the bending region, then flexible display can be monitored, but cracks from bending may cause water vapor penetration affecting circuit performance
Solution Approach 1:
The crack detection lines are pre-positioned in the bending region before the display undergoes operational stress. This preliminary placement allows the detection system to identify potential crack formation early in the bending process, enabling preventive measures to be taken before water vapor penetration can occur and damage the circuits.
Solution Approach 2:
The detection lines provide real-time feedback about the structural integrity of the flexible display during bending operations. By monitoring resistance changes or continuity in the detection lines, the system can detect cracks as they form in the bending region, providing feedback that alerts to potential water vapor penetration risks before they affect circuit performance.
Data Source
AI summary
Disclosed is a display substrate including a display region and a peripheral region, the peripheral region includes a bending region located on one side of the display region and further includes a first crack detection line including a first lead segment, a second lead segment, a third lead segment, and a fourth lead segment, the first and fourth lead segments are at least partially located in the bending region, the second and third lead segments at least partially surround the display region. The display substrate further includes a pixel definition layer having a first boundary on a side of a first via away from the display region and a touch insulation layer having a second boundary on the side of the first via away from the display region, and the second boundary is located on a side of the first boundary away from the display region.