OLED Bank Insulating Layer Vertical Edge Alignment
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Solution Overview
Problem
In organic light-emitting display devices, the deposition shadow during the manufacturing process causes the organic light-emitting layer and bank insulating layer to extend into non-display areas, leading to moisture ingress, reduced lifespan, and compromised rigidity due to increased lengths in these areas.
Innovation Solution
The organic light-emitting layer and bank insulating layer are confined to the display area by vertically aligning their side surfaces with the non-display area, using an organic ashing process to remove excess material from the non-display area, and incorporating a protective and capping layer to prevent moisture entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the deposition process uses a mask on the lower substrate, then the organic light-emitting layer and bank insulating layer can be formed, but deposition shadow occurs causing the layers to extend into non-display areas
Solution Approach 1:
The patent applies preliminary action by forming the bank insulating layer with extended sides before the deposition process, so that the mask can be positioned precisely on top of it. This pre-established structure serves as a reference for accurate mask alignment, preventing deposition shadow from causing organic material to extend into non-display areas.
Solution Approach 2:
The patent replaces the mechanical alignment system (relying solely on mask positioning on the substrate) with a reference-based system. The bank insulating layer's extended sides provide a physical reference that substitutes for complex mechanical alignment mechanisms, enabling more precise control of deposition boundaries.
2Productivity
If the organic light-emitting layer and bank insulating layer extend into non-display areas, then deposition is complete, but moisture can ingress through these extended layers reducing device lifespan
Solution Approach 1:
The patent uses preliminary action by pre-forming the bank insulating layer with sides that extend beyond the lower electrode edges. This extended structure serves as a preliminary barrier that prevents organic material from reaching the non-display area during deposition, thereby eliminating the moisture ingress pathway before it can form.
Solution Approach 2:
The extended sides of the bank insulating layer act as an intermediary barrier between the organic light-emitting layer and the non-display area. This intermediate structure prevents direct contact between the organic material and the non-display region, blocking the moisture ingress path while allowing complete deposition coverage in the display area.
3Productivity
If the organic light-emitting layer and bank insulating layer extend into non-display areas, then deposition is complete, but the bonding area with adhesive layer is reduced compromising device rigidity
Solution Approach 1:
The patent applies preliminary action by establishing the bank insulating layer with extended sides before deposition. This pre-formed structure defines the boundaries that prevent organic material extension, thereby preserving the full non-display area for adhesive bonding and maintaining device rigidity.
Solution Approach 2:
The extended bank insulating layer serves as an intermediary that separates the organic light-emitting structure from the non-display area. This mediation ensures that organic materials do not encroach on the bonding region, allowing the adhesive layer to maintain full contact with the lower substrate for optimal rigidity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration prevents moisture ingress, enhances the lifespan of the light-emitting structure, and maintains the rigidity of the display device by ensuring the organic layers do not act as paths for moisture and maintaining an adequate bonding area with the adhesive layer.
Implementation Method 1
a light-emitting structure located in a display area of a lower substrate. The light-emitting structure may include, for example, a lower electrode, an organic light-emitting layer, and an upper electrode
Implementation Method 2
The organic light-emitting layer and the bank insulating layer may be formed through a deposition process using a mask
Data Source
AI summary
An organic light-emitting display device according to an embodiment includes a light-emitting structure. The light-emitting structure includes a lower electrode, an organic light-emitting layer, and an upper electrode, which are stacked one above another in sequence. The organic light-emitting display device further includes a bank insulating layer covering the edge of the lower electrode. The organic light-emitting layer extends onto the bank insulating layer. The organic light-emitting layer includes a side surface being vertically aligned with a side surface of the bank insulating layer.