Organic EL Device Height Difference-Relieving Layer
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Solution Overview
Problem
The manufacturing process of organic EL devices faces issues with air bubbles forming at the boundary between different colored layers in the color filter, leading to deteriorated display quality, reduced adhesiveness, and substrate separation due to height differences.
Innovation Solution
A height difference-relieving layer is introduced between the color filter and the adhesive, which is formed using the same material as the bank and can be either concave or convex, to alleviate surface height differences and facilitate even adhesive spreading, thereby reducing air bubble incorporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If adhesive is spread over the entire surface of the color filter by dropping on the central portion, then the adhesive can be applied efficiently, but air bubbles are generated at the boundary between display region and non-display region due to height difference
Solution Approach 1:
A height difference-relieving layer is formed on the color filter surface before adhesive application. This preliminary action creates a substantially flat surface that prevents air bubble generation during subsequent adhesive spreading, while maintaining efficient central dropping application method
Solution Approach 2:
The height difference-relieving layer acts as an intermediary between the color filter (with height differences) and the adhesive. It mediates the height difference problem by providing a flat surface for adhesive application, preventing air bubble incorporation while maintaining efficient manufacturing
2Manufacturing precision
If the color filter has large height difference at the boundary between display region and non-display region, then the colored layers can be formed as required, but adhesiveness between color filter and adhesive worsens and counter substrate separates
Solution Approach 1:
The height difference-relieving layer is selectively formed only on specific regions of the color filter where height differences exist (display region or boundary areas). This local modification maintains the required colored layer structure while locally eliminating height difference problems that cause adhesion failure
Solution Approach 2:
The height difference-relieving layer is formed in advance on the color filter surface before adhesive application. This preliminary flattening action ensures uniform adhesive distribution and strong bonding between the color filter and counter substrate, preventing separation
Data Source
AI summary
An organic EL device includes an organic light-emitting layer provided above a first substrate; a protective layer provided above the organic light-emitting layer; a color filter provided on the protective layer; and a second substrate adhered to the color filter via an adhesive, in which a colored layer includes a first colored layer, a second colored layer, and a third colored layer, the color filter includes a first region in which the first colored layer, the second colored layer, and the third colored layer are respectively arranged as single colors and a second region in which the first colored layer, the second colored layer, and the third colored layer are arranged in a layered manner, and a height difference-relieving layer is provided between the color filter and the adhesive.