Flexible Display Buffer Layer Thickness Variation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing process of flexible organic light emitting display devices is complex due to the need for precise etching and uniformity across bend areas, which is challenging with existing technologies.
Innovation Solution
A flexible display design and manufacturing method that uses a single mask for both primary and secondary etching of the bend area, simplifying the process and improving uniformity by structuring the flexible substrate with specific layers and etching techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple masks are used for primary and secondary etching of the bend area, then the etching precision can be maintained, but the manufacturing process complexity increases
Solution Approach 1:
The patent combines primary and secondary etching operations into a single etching process using one mask, merging two separate manufacturing steps into one unified operation. This reduces process complexity while maintaining etching uniformity through the integrated approach and single mask design.
Solution Approach 2:
The single mask design performs multiple functions by serving as both the primary etching mask and the secondary etching mask. This multi-functional mask eliminates the need for separate masks and alignment processes, simplifying the manufacturing workflow while achieving the required etching precision.
2Ease of manufacture
If the buffer layer thickness is uniform across the entire substrate, then the manufacturing process is simplified, but the flexibility and bendability of the display device deteriorates
Solution Approach 1:
The patent applies different buffer layer thicknesses to different regions of the substrate. The first buffer layer has a first thickness in the active area and a second, greater thickness in the bend allowance section. This local variation in thickness provides flexibility where needed while maintaining structural integrity in other areas.
Solution Approach 2:
The buffer layer is segmented into multiple sections with different thickness characteristics. The bend allowance section has increased thickness to accommodate bending stresses, while the active area maintains a standard thickness. This segmentation allows the device to meet both flexibility requirements and manufacturing simplicity goals.
3Ease of manufacture
If the connection line is positioned only on the second insulation layer in the pad area, then the manufacturing process is simplified, but the reliability in the bend allowance section deteriorates
Solution Approach 1:
The connection line structure varies by region: in the pad area it is positioned on the second insulation layer for simple manufacturing, while in the bend allowance section it is positioned on the buffer layer for enhanced reliability. This local differentiation optimizes both manufacturing ease and connection reliability in different functional zones.
Data Source
AI summary
A flexible display includes a flexible substrate that includes an active area, a pad area extending from the active area, and a bend allowance section extending from the pad area. A first buffer layer is disposed on the flexible substrate and includes at least three layers. A first insulation layer is disposed on the first buffer layer in the pad area, a gate line is disposed on the first insulation layer and extends from the active area to the pad area, a second insulation layer is disposed on the gate line in the pad area, a connection line is electrically connected to the gate line, and a second buffer layer covers the connection line. A top layer among the at least three layers of the first buffer layer is disposed in the active area and the pad area, a lower layer which is in contact with the top layer extends to the bend allowance section and a thickness of the lower layer bend allowance section is less than a thickness of the lower layer in the other areas. A portion of the connection line is disposed on the second insulation layer in the pad area, and another portion of the connection line is disposed on the lower layer in the bend allowance section.