Display Capping Pattern for Uniform Touch-Line Patterning
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Solution Overview
Problem
The deposition of non-uniform layers in OLEDs during the patterning process for touch lines can lead to delamination due to leakage of organic material along inclined surfaces, causing defects such as cuts or scratches in the thin film encapsulation layer.
Innovation Solution
A display device design that includes a thickening pattern on inclined surfaces to prevent leakage of organic material, reducing the likelihood of delamination and abnormal patterning of touch signal lines by ensuring adequate photoresist thickness and using a cap to cover the inclined surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If layers are deposited along inclined surfaces during patterning process, then touch lines can be formed, but non-uniform layer thickness occurs leading to delamination
Solution Approach 1:
A capping pattern is formed on the inclined surface before the deposition of the encapsulation layer. This preliminary action creates a cap structure that provides a flat surface for subsequent layer deposition, preventing the inclined surface from causing non-uniform thickness and delamination issues.
Solution Approach 2:
The solution introduces an additional structural element (the capping pattern) in the vertical dimension. By adding this cap layer on top of the inclined surface, the deposition process occurs on a flat horizontal surface rather than following the inclined contour, thus achieving uniform layer thickness.
2Productivity
If photoresist thickness is insufficient on inclined surfaces, then patterning can proceed, but organic material leakage occurs causing delamination
Solution Approach 1:
The capping pattern is formed as a preliminary structure before encapsulation layer deposition. This cap provides adequate thickness coverage on inclined surfaces, preventing organic material leakage and maintaining layer adhesion without requiring excessive photoresist thickness that would slow down the patterning process.
Solution Approach 2:
The capping pattern acts as an intermediary structure between the inclined touch line structure and the encapsulation layer. It mediates the interaction by providing a flat surface that prevents direct contact between the encapsulation layer and the inclined surface, thereby preventing organic material leakage.
3Manufacturing precision
If mask is used to form encapsulation layer, then encapsulation can be achieved, but abnormal patterning such as cuts or scratches occurs on touch signal lines
Solution Approach 1:
The capping pattern is formed before the encapsulation layer deposition. This preliminary cap structure serves as a protective barrier that prevents the mask from directly contacting and damaging the touch signal lines during the encapsulation process, thereby eliminating mask-induced defects.
Solution Approach 2:
The capping pattern provides a cushioning protective layer beforehand. This cap absorbs or prevents any mechanical damage that might occur during mask handling and deposition processes, protecting the underlying touch signal lines from cuts or scratches.
Data Source
AI summary
A display device including a substrate having a display area and a peripheral area defined outside the display area, a circuit layer disposed on the substrate, a device layer disposed on the display area, an encapsulation layer covering the device layer, a touch sensing unit including at least one touch insulating layer disposed on the encapsulation layer, touch electrodes disposed on the encapsulation layer, and touch signal lines connected to the touch electrodes, a first section disposed in the peripheral area and including a first part having a first thickness, a second part having a second thickness less than the first thickness and overlapping the touch signal lines, and an intermediate part connecting the first part and the second part and being inclined, and a first thickening pattern overlapping at least the intermediate part.