OLED Spacer Volume Gradient for Edge Filler Diffusion
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Solution Overview
Problem
In organic light emitting diode displays, filler diffusion defects occur at the edges of the display substrate, leading to empty spaces and reduced mechanical strength due to the difficulty in filling these areas, which compromises the durability of the device.
Innovation Solution
The implementation of spacers with a larger volume as they approach the edges of the display substrate, either in a cross shape, combination of cross and straight shape, or in a specific direction, to maintain an interval between the substrates and ensure complete filler coverage, thereby preventing filler diffusion defects and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform spacers are used across the display substrate, then the structure is simple and easy to manufacture, but filler diffusion defects occur at the edges leading to empty spaces and reduced mechanical strength
Solution Approach 1:
The patent applies local quality by varying the volume of spacers based on their position on the display substrate. Spacers at the edge regions have larger volumes compared to spacers in the central region. This local differentiation ensures that filler material can properly diffuse and fill the edge regions without creating empty spaces, while maintaining appropriate spacing throughout the entire substrate. The local quality principle resolves the contradiction by making the spacer structure more complex only where needed (at edges) rather than uniformly across the entire substrate.
2Reliability
If larger volume spacers are used at edges, then filler diffusion defects are prevented and mechanical strength is improved, but the device complexity increases
Solution Approach 1:
The patent implements local quality by differentiating spacer volumes based on spatial location. Edge spacers are designed with larger volumes to prevent filler diffusion defects and enhance mechanical strength at critical edge regions, while central spacers maintain smaller, standard volumes. This localized approach improves reliability only where needed without unnecessarily increasing overall device complexity.
Solution Approach 2:
The patent applies partial action by providing excessive spacer volume specifically at the edge regions where filler diffusion problems occur, rather than uniformly increasing spacer volume across the entire substrate. This targeted excessive action at critical locations prevents filler defects and improves edge mechanical strength without the need to increase spacer volume everywhere, thus avoiding unnecessary device complexity.
3Strength
If spacer volume is increased at edges, then mechanical strength and durability are enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by specifying that spacers at edge regions have larger volumes than spacers in the central region. This localized volume increase targets the specific areas where mechanical strength is most critical, enhancing edge durability without requiring high-precision control across the entire substrate. The manufacturing process can use standard precision for central spacers and adjusted precision parameters only for edge spacers.
Data Source
AI summary
An organic light emitting diode display includes a first substrate, the first substrate including at least one organic light emitting diode and a pixel defining layer having an opening portion defining a light emitting region of the organic light emitting diode, protruding portions increasingly protruding on the pixel defining layer as the protruding portions approach the edges of the first substrate, a second substrate disposed opposite to the first substrate, a sealing member bonding the first substrate to the second substrate, and filler in a space between the first substrate and the second substrate.