Flexible TFT Substrate Hole Patterns for Crack Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flexible organic light emitting display devices suffer from cracks and the slip phenomenon when bent, leading to deterioration of the thin film transistor and reduced lifespan due to tension applied to the inorganic and organic insulation layers.
Innovation Solution
A flexible thin film transistor substrate and organic light emitting display device design featuring hole patterns in the inorganic and organic insulation layers to distribute bending stress and prevent crack propagation, maintaining transistor characteristics and extending device lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the flexible organic light emitting display device is repetitively bent or folded, then flexibility is achieved, but tension is applied to the inorganic insulation layer and the organic insulation layer causing cracks
Solution Approach 1:
The patent introduces hole patterns that segment the insulation layers (inorganic and organic) into isolated regions. These hole patterns are disposed at specific positions where cracks are likely to occur, dividing the continuous insulation layers into separate segments that can independently withstand bending stress without forming continuous crack paths.
Solution Approach 2:
The patent applies hole patterns selectively at specific locations within the insulation layers where stress concentration and crack initiation are most likely to occur during bending. This local modification provides targeted reinforcement without affecting the overall structure or requiring changes to the entire device.
2Adaptability or versatility
If cracks occur in the insulation layers, then flexibility is maintained, but cracks propagate to the organic light emission layer or the active layer causing performance deterioration
Solution Approach 1:
The hole patterns segment the insulation layers to create isolated regions that prevent crack propagation. When cracks occur, they are confined within individual segments between hole patterns and cannot coalesce into continuous paths that would reach the organic light emission layer or active layer, thus maintaining device reliability.
Solution Approach 2:
The hole patterns act as intermediary structures that interrupt the stress transmission path from the flexible substrate to the sensitive functional layers. By creating discontinuities in the insulation layers, the hole patterns prevent mechanical stress from propagating to the organic light emission layer and active layer.
3Ease of manufacture
If the inorganic insulation layer and organic insulation layer are continuously structured, then manufacturing is simplified, but bending stress concentrates causing crack generation and slip phenomenon
Solution Approach 1:
The patent introduces hole patterns that segment the continuously structured insulation layers into isolated regions. This segmentation is implemented using standard photolithography and etching processes, adding minimal manufacturing complexity while dramatically improving the structure's ability to withstand bending stress and prevent interface bonding failure.
Data Source
AI summary
Provided are a flexible thin film transistor substrate and a flexible organic light emitting display device. The flexible thin film transistor substrate includes: a flexible substrate including at least one thin film transistor (TFT) area and having flexibility, an active layer disposed in the TFT area on the flexible substrate, a gate insulation layer disposed on the active layer, a gate electrode overlapping with the active layer on the gate insulation layer, an insulating interlayer disposed on the gate electrode, and a source electrode and a drain electrode disposed on the insulating interlayer and connected with the active layer, respectively. The gate insulation layer or the insulating interlayer includes at least one hole pattern configured to reduce bending stress.