Chamfered Aperture Partition for OLED Brightness Uniformity
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Solution Overview
Problem
Conventional organic light emitting displays (OLEDs) face issues with non-uniform brightness due to incomplete filling of organic material in apertures with sharp corners, leading to thickness inconsistencies and potential short circuits.
Innovation Solution
The use of a partition member with a quadrangular aperture shape having chamfered corners and an emitting control layer made of materials like silicon oxide or polysilicon, which extends to cover the edges of the aperture, ensuring uniform dispersion and formation of the organic light emitting layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rectangular aperture with right angles is used, then the manufacturing process is simple, but the organic material cannot fill the sharp corners completely, leading to non-uniform thickness and brightness
Solution Approach 1:
The patent applies asymmetry by modifying the aperture corners from sharp right angles to chamfered corners (oblique angles). This asymmetric modification at the corner regions allows organic material to flow and fill the aperture completely, eliminating the filling problem while maintaining a simple quadrangular overall shape that is easy to manufacture.
Solution Approach 2:
The patent applies curvature by replacing the sharp angular corners with chamfered surfaces that create a more gradual transition. This curved/angled surface modification enables the liquid organic material to wet and fill the corner regions effectively, achieving uniform thickness without compromising manufacturing simplicity.
2Productivity
If the aperture corners are not completely filled with organic material, then the manufacturing process is simpler, but the display luminance lacks uniformity and short circuits may occur
Solution Approach 1:
By chamfering the aperture corners, the patent creates an asymmetric geometry that promotes complete organic material filling. This design ensures uniform thickness and prevents short circuits while maintaining manufacturing efficiency, as the chamfered corners are easily formed during the aperture fabrication process.
3Area of stationary object
If the aperture has sharp corners, then the opening ratio can be maximized, but the organic material surface tension prevents complete filling, causing thickness non-uniformity
Solution Approach 1:
The patent maintains a large aperture opening area by using a quadrangular shape with chamfered corners. The chamfering modifies only the corner regions while preserving the overall aperture size, thus maximizing the opening ratio while enabling complete organic material filling and uniform thickness.
Solution Approach 2:
By replacing sharp corners with chamfered surfaces, the patent creates a geometry that facilitates organic material wetting and filling. This modification maintains the aperture area while eliminating the surface tension-related filling problems at the corners.
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 brightness uniformity and prevents short circuits by ensuring complete filling of the aperture, resulting in improved display quality and increased opening ratios.
Implementation Method 1
Organic material has a liquid phase which has the property of keeping surface tension energy as low as possible. Therefore, when organic material is dispensed onto the anode through the aperture, the organic material forms into a spherical shape to keep the surface tension energy low.
Implementation Method 2
The emitting control layer includes a material, such as silicon oxide, silicon nitride, amorphous silicon, or polysilicon, having an affinity to organic material for forming a light emitting layer.
Data Source
AI summary
A display device including a substrate, a first electrode formed over the substrate, and a partition member having a first aperture is provided. The display device further includes an emitting control layer covering a portion of the first aperture, thereby providing a second aperture to expose a portion of the first electrode, wherein the second aperture has a quadrangular shape with chamfered corners which help disperse organic material uniformly. Advantageously, the emitting control layer is formed of a material having an affinity to an organic material forming an organic light emitting layer within the second aperture, thereby helping to disperse the organic material uniformly and improve brightness uniformity.