OLED Pixel Separation Layer Sidewall Curvature Design
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Solution Overview
Problem
OLED display devices face deterioration of light emission characteristics and risk of shorting due to moisture and oxygen ingress through the sidewalls of inorganic pixel separation layers, which can lead to broken organic light-emitting layers and electrode shorts.
Innovation Solution
An OLED display device with a pixel separation layer formed from an inorganic material, featuring a sidewall structure with a first curved section, a linear section, and a second curved section, where at least one tangential plane of these sections forms an included angle of less than 85° with the substrate, preventing moisture and oxygen penetration and maintaining uniform thickness of the organic light-emitting layer and common electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pixel separation layer is made of an inorganic material with vertically erected sidewalls (at approximately 90 degrees), then the moisture and oxygen content in the pixel separation layer is reduced, but the organic light-emitting layer and common electrode become significantly thinner or broken at the sidewall portions, allowing moisture and oxygen to enter and causing deterioration of light emission characteristics
Solution Approach 1:
The pixel separation layer sidewall is designed with curved sections instead of vertical straight lines. The sidewall includes a first curved section at the top, a linear section in the middle, and a second curved section at the bottom, where the curved sections form angles less than 85° with the substrate. This curvature prevents the organic light-emitting layer and common electrode from becoming thin or broken, while still using inorganic material to block moisture and oxygen.
Solution Approach 2:
The angle of the sidewall is changed from approximately 90° (vertical) to less than 85° relative to the substrate. This parameter change in the sidewall geometry allows the organic light-emitting layer and common electrode to maintain uniform thickness while still achieving effective moisture and oxygen barrier properties through the inorganic material composition.
2Object-affected harmful factors
If the pixel separation layer is made of an organic material, then the interface between the pixel separation layer and organic light-emitting layer allows moisture and oxygen to spread into the organic light-emitting layer, causing deterioration of light emission characteristics
Solution Approach 1:
The pixel separation layer is constructed from inorganic materials that form a composite structure with the organic light-emitting layer. This composite approach allows the inorganic pixel separation layer to provide moisture and oxygen barrier properties while the curved sidewall geometry ensures uniform thickness of the organic light-emitting layer, preventing deterioration of light emission characteristics.
3Reliability
If the organic light-emitting layer is broken at the sidewall site, then the distance between the common electrode and pixel electrode becomes extremely close, leading to shorting between the two electrodes and damaging the organic light-emitting layer
Solution Approach 1:
The curved sidewall sections with angles less than 85° prevent the organic light-emitting layer from breaking by distributing stress uniformly across the structure. This curvature design maintains adequate distance between the common electrode and pixel electrode, preventing shorting while preserving the structural integrity of the organic light-emitting layer.
Data Source
AI summary
The present invention provides an OLED display device, which includes: a substrate (1), a plurality of pixel zones arranged in an array on the substrate (1), each of the pixel zones comprising a pixel electrode (2), an organic light-emitting layer (3), and a common electrode (4) that are sequentially stacked on the substrate (1), and a pixel separation layer (5) including a plurality of openings, the openings being each delimited and circumferentially surrounded by a pixel separation layer sidewall (51), each of the openings corresponding to one of the pixel zones. The pixel separation layer (5) is formed of an inorganic material. The pixel separation layer sidewall (51) includes, arranged from top to bottom, a first curved section (511), a linear section (512), and a second curved section (513), so as to overcome a deterioration issue of the organic light-emitting layer (3) caused by the pixel separation layer sidewall (51), prevent the organic light-emitting layer (3) and the common electrode (4) from breaking at a site corresponding to the pixel separation layer sidewall (51), prevent shorting between the common electrode (4) and the pixel electrode (2), which are the cathode and anode of the OLED display device, and improve displaying performance.