OLED Passivation Layer Morphology Control
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Solution Overview
Problem
Organic light emitting display (OLED) devices face issues with short circuits due to the morphologically uneven inorganic passivation layers, which also lead to decomposition of organic layers from moisture, affecting the device's lifespan.
Innovation Solution
The use of an organic passivation layer with a calcium (Ca) layer to prevent short circuits and moisture ingress, formed by applying a high molecular weight organic insulating material and additional moisture absorbent layers to ensure a planar surface for electrode formation and effective moisture removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an inorganic passivation layer is used, then the device structure is simplified, but the surface becomes morphologically uneven causing short circuits
Solution Approach 1:
The patent uses a composite structure combining organic passivation layer materials (such as polyimide, BCB, or PMMA) with specific molecular weight ranges (10,000-1,000,000) to achieve both structural simplicity and surface uniformity. The organic material forms a smooth surface that prevents short circuits while maintaining device simplicity.
Solution Approach 2:
The patent changes the material parameter from inorganic to organic passivation layer, and specifically controls the molecular weight parameter within 10,000-1,000,000 range. This parameter change transforms the surface morphology from uneven to smooth, resolving the contradiction between structural simplicity and manufacturing precision.
2Ease of manufacture
If an inorganic passivation layer is used, then the fabrication process is simplified, but moisture ingress causes organic layer decomposition
Solution Approach 1:
The patent changes the material type parameter from inorganic to organic passivation layer, which inherently provides better moisture barrier properties. This material parameter change maintains ease of fabrication while significantly improving reliability by preventing moisture ingress that causes organic layer decomposition.
Solution Approach 2:
The organic passivation layer creates a protective environment that excludes moisture (acts as an inert barrier) from reaching the organic emission layers. This protective environment prevents chemical degradation of the organic materials while maintaining fabrication simplicity.
3Ease of manufacture
If the passivation layer surface is uneven, then material deposition is simpler, but electrode formation is compromised
Solution Approach 1:
The patent changes the surface morphology parameter by selecting organic materials with specific molecular weights (10,000-1,000,000) that naturally form smooth surfaces during deposition. This single parameter change simultaneously ensures easy material deposition and precise electrode formation by providing a uniform substrate.
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 solution prevents short circuits and enhances the OLED device's lifespan by ensuring a smooth surface for electrode formation and effectively removing moisture, thereby improving the yield and longevity of the OLED device.
Implementation Method 1
forming a calcium (Ca) layer... effectively removing moisture
Implementation Method 2
The organic passivation layer... prevent decomposition of organic layers caused by moisture
Data Source
AI summary
An OLED device and a method for fabricating the same are disclosed, capable of improving yield and preventing decomposition of organic layers by moisture. An organic passivation layer having excellent morphology is applied to prevent a short circuit between an anode electrode and a cathode electrode. A Ca layer is applied to remove moisture from the inside of the device, thereby increasing the lifespan of the device. Accordingly, generation of dark sports by the short circuit caused by protrusions on a poor-morphology layer can be prevented. In addition, moisture absorbent layers are formed between the passivation layers and the partitions to remove outside moisture and the moisture outgassed from the inside, that is, partitions and organic layers, thereby elongating the lifespan of the OLED device.