Display Electrode Structure With Rounded Corners to Prevent Sidewalls
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Solution Overview
Problem
Display devices face issues with unwanted sidewalls forming on light-emitting elements during the formation of connecting electrodes, leading to defects and potential short circuits due to the rearrangement phenomenon during the etching process.
Innovation Solution
A display device design featuring pixel electrodes, light-emitting elements, and connecting electrodes with a nonvolatile material, where the connecting electrodes have a greater width and rounded corners, and a stepped insulating layer structure to prevent sidewall formation, along with a method of fabricating the device using hard mask patterns and etching processes to form light-emitting and connecting electrodes with rounded corners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If connecting electrodes are formed by etching a nonvolatile connecting electrode layer during light-emitting element formation, then connecting electrodes can be successfully created, but sidewalls are formed on light-emitting elements due to rearrangement phenomenon
Solution Approach 1:
The patent applies preliminary action by forming a protective coating layer on the light-emitting element surface before the etching process. This coating layer prevents the rearrangement phenomenon from affecting the light-emitting element shape during subsequent etching of the connecting electrode layer, thus solving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent introduces a protective coating layer as an intermediary between the etching process and the light-emitting element surface. This intermediary layer allows the etching to proceed for connecting electrode formation while preventing unwanted material rearrangement on the light-emitting elements, resolving the technical contradiction.
2Reliability
If connecting electrodes have greater width than light-emitting elements, then electrical connection is improved, but corner sharpness increases leading to potential short circuits
Solution Approach 1:
The patent applies spheroidality by rounding the corners of both the light-emitting elements and the connecting electrodes. This curvature design eliminates sharp corners that could cause short circuits while maintaining the wider connecting electrode structure for reliable electrical connection, thus resolving the contradiction between connection reliability and short circuit prevention.
Data Source
AI summary
A display device includes a plurality of pixel electrodes on a substrate, light-emitting elements on the plurality of pixel electrodes and extending in a thickness direction of the substrate and connecting electrodes between the plurality of pixel electrodes and the light-emitting elements, wherein a width of the connecting electrodes is greater than a width of the light-emitting elements, and upper corners of each of the light-emitting elements and upper corners of each of the connecting electrodes are rounded.