OLED Pixel Define Layer Groove Design for Contact Reliability
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Solution Overview
Problem
The formation of detached spaces between the organic emissive layer and the electrodes in OLED display apparatuses leads to reduced light emitting efficiency and image quality, particularly at the edges of the opening where the contact quality deteriorates due to height differences and bending of the intermediate layer.
Innovation Solution
A method involving the formation of a groove on the insulating layer between adjacent TFTs, which allows the pixel define layer to fill the groove, reducing the step between the first electrode and the pixel define layer, thereby improving contact quality and preventing detachment of the intermediate layer from the first electrode, and using a thermal transfer method to form the intermediate layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pixel define layer is formed directly on the first electrode without a groove, then the manufacturing process is simpler, but detached spaces occur between the organic emissive layer and the first electrode leading to poor contact quality
Solution Approach 1:
A groove is formed in the insulating layer before depositing the pixel define layer. This preliminary structural preparation allows the pixel define layer to properly conform to the underlying topology, ensuring complete coverage and direct contact with the first electrode surface, thereby preventing detached spaces and improving contact quality.
2Reliability
If the intermediate layer is formed by conventional deposition methods, then the process is straightforward, but the organic emissive layer does not make proper contact with the first electrode at edge regions
Solution Approach 1:
The groove is formed in advance in the insulating layer to create a preparatory structure that guides the intermediate layer formation. This allows the organic emissive layer to properly contact the first electrode at edge regions during subsequent deposition, ensuring complete coverage without detachment.
3Reliability
If there is a large step between the first electrode and pixel define layer, then the pixel define layer can be easily formed, but the intermediate layer bends and detaches from the first electrode
Solution Approach 1:
The groove is formed beforehand to create a gradual transition structure. This preliminary action allows the pixel define layer to be deposited with better thickness uniformity while preventing excessive steps that would cause intermediate layer bending and detachment, thus maintaining both adhesion and manufacturing precision.
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 approach enhances the luminescent properties by ensuring proper contact between the intermediate layer and the first electrode, reducing non-emissive regions and maintaining the uniform thickness and insulating properties of the pixel define layer, thus improving overall image quality.
Implementation Method 1
The intermediate layer may be formed using a thermal transfer method.
Data Source
AI summary
An organic light emitting diode (OLED) display apparatus, including a substrate, at least one thin film transistor (TFT) on the substrate, an insulating layer covering the at least one TFT and having a via hole and a groove, a first electrode on the insulating layer and electrically connected to the at least one TFT through the via hole, a pixel define layer on the first electrode and the groove, the pixel define layer having an opening that exposes the first electrode; an intermediate layer electrically connected to the first electrode through the opening, the intermediate layer including an organic emissive layer, and a second electrode on the intermediate layer. The organic emissive layer may be easily formed in the opening because a step between the organic emissive layer and the pixel define layer may be reduced as a portion of pixel define layer fills the groove.