OLED Substrate Protrusions Reduce Cathode Contact Resistance
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Solution Overview
Problem
In OLED displays manufactured using the nozzle printing method, organic materials often accumulate in non-display regions, particularly in cathode contact areas, leading to increased contact resistance due to the difficulty in removing these materials during the manufacturing process.
Innovation Solution
The OLED display incorporates a substrate with a non-display region featuring protrusions and recessions of varying unit opening areas, strategically designed to minimize the accumulation of organic materials. These patterns are formed in the outgassing and cathode contacting regions to facilitate easier removal of organic raw materials, thereby reducing contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous ejection operation is performed to uniformly apply organic raw material onto display region, then manufacturing efficiency is improved, but organic material accumulates in non-display regions leading to increased contact resistance
Solution Approach 1:
The patent applies local quality by creating protrusions with different heights in different regions of the non-display area. First protrusions are formed in regions corresponding to sub-pixels, while second protrusions are formed in regions corresponding to spaces between sub-pixels. This local differentiation allows selective accumulation of organic material in appropriate areas while preventing accumulation in cathode contact regions, thereby resolving the contradiction between manufacturing efficiency and contact resistance.
Solution Approach 2:
The non-display region is segmented into multiple protrusions with different heights and positions. By dividing the non-display region into first protrusions (corresponding to sub-pixels) and second protrusions (corresponding to spaces between sub-pixels), the patent creates distinct zones for organic material accumulation. This segmentation allows the continuous ejection process to deposit material uniformly across the display region while directing excess material to designated protrusion areas, preventing contact resistance increase.
2Reliability
If additional processing operation is performed to remove organic material from cathode contact region, then contact resistance is reduced, but manufacturing complexity and time increase
Solution Approach 1:
The patent implements preliminary action by forming protrusions and recessions in the non-display region before applying organic raw material. These pre-formed structural features guide the organic material to accumulate on protrusions during the deposition process, automatically preventing material from reaching cathode contact regions. This preliminary structural preparation eliminates the need for subsequent organic material removal operations, reducing both manufacturing complexity and processing time while maintaining low contact resistance.
Solution Approach 2:
The protrusion structure performs self-service by automatically directing and containing organic material during deposition. The height difference between first and second protrusions creates a self-guiding effect where organic material naturally accumulates on the protrusions rather than spreading to cathode contact regions. This self-organizing behavior eliminates the need for external intervention or additional processing steps to remove excess material, simplifying the overall manufacturing process.
Data Source
AI summary
An organic light-emitting diode (OLED) display includes a substrate and a plurality of sub-pixels formed on the substrate, wherein the substrate includes a display region having formed therein sub-pixels to which colored organic materials are applied, and a non-display region formed at edges of the display region. The non-display region includes an outgassing portion and a cathode contacting portion, and protrusions and recessions having different numbers and unit opening areas are formed in at least one of the outgassing portion and the cathode contacting region. Thus, organic raw materials applied during manufacturing process may be prevented from remaining. Therefore, an increase in contact resistance due to organic raw materials remaining in a cathode contact region may be reduced.