Display Electrode Connection Structure for Crack-Resistant LED Bonding
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Solution Overview
Problem
Display devices face challenges in maintaining stable connections between light-emitting elements and electrodes, leading to increased resistance and decreased luminous efficiency due to cracks in connection electrodes, which also prolong the etching process and affect fine pattern manufacturing.
Innovation Solution
Incorporating pattern portions made of organic materials between the light-emitting elements and electrodes, with specific angles and shapes to reduce gradient changes in connection electrodes, and using inorganic and organic protection portions to enhance stability and reduce the thickness of connection electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separately formed light-emitting element is disposed on the electrode, then the light-emitting element can be electrically connected to the electrode, but the connection stability deteriorates due to cracks in the connection electrode
Solution Approach 1:
An organic pattern portion is introduced as an intermediary layer between the connection electrode and the light-emitting element. This pattern portion has a specific inclined surface that gradually transitions the thickness of the connection electrode, preventing abrupt changes that cause cracking. The intermediary layer absorbs stress and maintains connection stability without compromising electrical connectivity.
Solution Approach 2:
The thickness of the connection electrode is gradually changed through the inclined surface of the organic pattern portion. Instead of maintaining uniform thickness, the electrode thickness transitions from thicker to thinner regions, creating a gradient structure that reduces stress concentration and prevents crack formation during the connection process.
2Reliability
If the connection electrode thickness is increased to prevent cracks, then connection stability improves, but the etching process time increases and fine pattern manufacturing becomes difficult
Solution Approach 1:
The connection electrode thickness is changed from uniform to gradient distribution through the organic pattern portion. This allows the electrode to have sufficient thickness in critical areas for stability while being thinner in other areas, enabling faster etching and finer pattern manufacturing without compromising overall connection reliability.
Solution Approach 2:
The connection electrode is segmented into different thickness regions by the organic pattern portion, creating a gradient structure. This segmentation allows different parts of the electrode to serve different functions: thicker regions provide stability while thinner regions enable efficient etching and fine patterning.
3Productivity
If the connection electrode is made thinner to reduce etching time, then manufacturing efficiency improves, but connection stability deteriorates due to increased cracking
Solution Approach 1:
The connection electrode thickness is optimized through gradient changes enabled by the organic pattern portion. The electrode can be made thinner overall to improve manufacturing efficiency and reduce etching time, while the gradual thickness transition prevents cracking that would otherwise occur in uniformly thin electrodes, thereby maintaining connection stability.
4Ease of manufacture
If a uniform thickness connection electrode is used, then manufacturing is simpler, but cracks occur due to abrupt gradient changes
Solution Approach 1:
The organic pattern portion serves as a mediator that enables the creation of a gradient thickness structure in the connection electrode. While this adds a manufacturing step, it prevents cracking and improves reliability, making the overall process more efficient by reducing defects and rework.
Solution Approach 2:
The connection electrode thickness parameter is changed from uniform to gradient distribution. This parameter change introduces a gradual transition zone that prevents abrupt stress changes, eliminating cracks while maintaining manufacturing feasibility through the organic pattern portion.
Data Source
AI summary
A display device includes a first electrode, a second electrode, a light-emitting element, a first pattern portion which is disposed adjacent to a first area in which the first electrode and the light-emitting element overlap each other in a plan view, a second pattern portion which is disposed adjacent to a second area in which the second electrode and the light-emitting element overlap each other in a plan view, a first connection electrode which covers the light-emitting element and the first pattern portion and is electrically connected to the light-emitting element and the first electrode, and a second connection electrode which covers the light-emitting element and the second pattern portion and is electrically connected to the light-emitting element and the second electrode.