OLED Overcoat Layer Thickness Optimization for Light Transmittance
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Solution Overview
Problem
Conventional OLED devices with a color filter on array (COA) structure face issues with non-uniform surfaces and irregular electric fields due to the thickness of the overcoat and silicon nitride layers, leading to reduced light transmittance and brightness, especially when trying to maintain white balance over time.
Innovation Solution
The formation of an overcoat layer and an insulating layer at optimized thicknesses, specifically between 1.1 μm to 2.1 μm, improves light transmittance by patterning and removing portions of the silicon nitride layer in the light emitting region, ensuring a uniform electric field and enhancing the OLED device's brightness and color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick overcoat layer and silicon nitride layer are formed to maintain white balance and prevent non-uniform surface, then the electric field uniformity is improved, but the light transmittance and brightness deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness of the overcoat layer (100-300 nm) and silicon nitride layer (50-150 nm) to optimize the balance between white balance stability and light transmittance. By adjusting these dimensional parameters, the invention achieves both uniform electric field distribution and high brightness without compromising either requirement.
2Stability of the object's composition
If the overcoat layer thickness is increased to prevent non-uniform surface, then the electric field uniformity is improved, but the light transmittance decreases
Solution Approach 1:
The patent resolves this contradiction by optimizing the overcoat layer thickness parameter to a specific range (100-300 nm). This precise parameter control ensures that the surface remains uniform enough to maintain electric field stability while remaining thin enough to allow high light transmittance, thus achieving both surface uniformity and brightness requirements simultaneously.
3Reliability
If conventional layer thicknesses are used to ensure structural integrity, then the device reliability is maintained, but the brightness and color gamut are reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of multiple layers including the overcoat layer (100-300 nm) and silicon nitride layer (50-150 nm). These optimized parameters maintain structural integrity and device reliability while significantly improving light transmittance, thereby enhancing both brightness and color gamut without sacrificing device stability.
Data Source
AI summary
An organic light emitting display device and a method for manufacturing the same are disclosed. The method for manufacturing the organic light emitting display device includes forming a switching element and a silicon nitride layer over a substrate, patterning and removing a portion of the silicon nitride layer formed on a light emitting region through which light is transmitted, forming an overcoat layer formed on the silicon nitride layer, wherein a portion of the overcoat layer corresponding to the light emitting region has a thickness of about 1.1 μm to about 2.1 μm, forming a first electrode electrically connected to the switching element over the light emitting region, and sequentially forming an organic light emitting layer and a second electrode on the first electrode.