OLED Array Substrate Segmented Cathode Trace for Narrow Border Encapsulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Narrowed borders in OLED displays make it difficult to encapsulate cathode traces with inorganic package layers, leading to water vapor invasion and organic layer overflow, causing package failures.
Innovation Solution
The array substrate features a pixel definition layer with trapezoidal recesses and protrusions, where the cathode trace is placed on the surface of the protrusions and the bottom of the recesses, creating a gap, and an organic elevation layer is used to enhance water and oxygen barrier performance and prevent organic layer overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the lower border is narrowed to achieve full screen display, then the display area is increased, but the cathode trace becomes difficult to encapsulate with inorganic package layers
Solution Approach 1:
The pixel definition layer is divided into multiple recesses and protrusions, creating a segmented structure that allows the cathode trace to be discontinuously disposed. This segmentation enables the trace to be positioned away from the package region edge while maintaining full screen display, thus achieving both increased display area and reliable encapsulation.
Solution Approach 2:
The invention introduces vertical dimensionality by creating recesses and protrusions in the pixel definition layer. The cathode trace is disposed on the surface of protrusions and bottom surfaces of recesses, utilizing the third dimension (depth) to achieve proper spacing and encapsulation while maintaining a narrow lower border for full screen display.
2Length of stationary object
If the pixel region is closer to the package region to achieve narrow borders, then the border width is reduced, but water vapor invasion becomes more likely causing light-emitting material failure
Solution Approach 1:
The pixel definition layer is segmented into recesses and protrusions, creating a discontinuous cathode trace structure. This segmentation increases the path length for water vapor and oxygen to reach the light-emitting material, providing enhanced protection even when the pixel region is close to the package region.
Solution Approach 2:
The recesses and protrusions in the pixel definition layer act as intermediary structures between the cathode trace and the package region. These structures create physical barriers and increase the diffusion path for water vapor and oxygen, protecting the light-emitting material from harmful environmental factors.
3Length of stationary object
If the pixel region is closer to the retaining wall to achieve narrow borders, then the border width is reduced, but the organic package film overflows causing package failure
Solution Approach 1:
The pixel definition layer is segmented into recesses and protrusions, creating a discontinuous cathode trace structure. This segmentation provides physical barriers that prevent the organic package film from overflowing, maintaining package integrity even with narrow borders.
Solution Approach 2:
The recesses and protrusions are formed in advance in the pixel definition layer before package film deposition. This preliminary action creates pre-defined barriers that guide and constrain the organic package film, preventing overflow before it can occur during the packaging process.
Data Source
AI summary
In an embodiment, an array substrate includes a substrate having a display region and a package region surrounding the display region, wherein the display region comprises a side region adjacent to the package region; a pixel definition layer disposed on the display region of the substrate, wherein the pixel definition layer is formed with a plurality of recesses and a plurality of corresponding protrusions surrounding each recess, and each recess and each protrusion correspond to the side region; and a cathode trace disposed on a surface of each protrusion and a bottom surface of each recess, wherein a gap exists between the cathode trace on each protrusion and the cathode trace in each recess.