Top-Emission OLED Auxiliary Electrode Laser Transfer
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Solution Overview
Problem
Top-emission OLED devices face issues with uneven luminescence due to large sheet resistance and IR drop in the cathode, which are exacerbated by the need for auxiliary electrodes that are opaque and incompatible with the organic light-emitting layer, leading to poor contact and alignment challenges, especially in larger panels.
Innovation Solution
A method involving the formation of auxiliary electrodes on a resin layer, a gas generation layer, and an organic light-emitting layer, followed by laser irradiation to transfer the organic light-emitting layer to a receptor substrate, allowing for the formation of a cathode on the auxiliary electrodes, thereby improving contact and reducing pixel defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If auxiliary electrodes are added to reduce IR drop and improve brightness uniformity, then brightness uniformity is improved, but the auxiliary electrodes are opaque and cannot be placed over the EML, requiring complex cell assembly processes
Solution Approach 1:
The patent extracts the auxiliary electrode function from the traditional cell assembly process by forming auxiliary electrodes directly on the array substrate before EML deposition. This separates the electrical function (auxiliary electrode) from the optical function (EML), allowing the auxiliary electrode to perform its current-spreading function without blocking light in the final device structure.
Solution Approach 2:
The auxiliary electrodes are formed in advance on the array substrate before the EML is deposited. This preliminary formation allows the auxiliary electrodes to be integrated into the substrate structure, eliminating the need for post-assembly contact mechanisms and simplifying the overall device structure.
2Reliability
If auxiliary electrodes are formed on the array substrate, then contact with cathode is improved, but the contact between conductive layer on spacer and cathode is surface contact producing poor contact
Solution Approach 1:
The patent transitions from surface contact (2D) to point contact (0D) by having the auxiliary electrode extend vertically through the spacer to contact the cathode. This dimensional change from surface to point contact ensures reliable electrical connection while simplifying the manufacturing process by eliminating the need for precise surface alignment.
Solution Approach 2:
The auxiliary electrode acts as an intermediary element that bridges the array substrate and the cathode. By extending through the spacer, it provides a direct conductive path between these two components, ensuring reliable contact without requiring the spacer's conductive layer to make surface contact with the cathode.
3Manufacturing precision
If FMM evaporation is used to form auxiliary electrodes, then alignment can be achieved, but for large panels the mask becomes large and alignment problems occur due to gravity effect
Solution Approach 1:
The patent replaces the mechanical FMM system with a direct deposition process where auxiliary electrodes are formed on the array substrate without requiring large masks. This substitution eliminates gravity-induced mask alignment problems while maintaining precise alignment through the deposition process itself, enabling scalable production for large-panel displays.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process enhances the uniformity of brightness and reduces pixel defects by ensuring better contact between auxiliary electrodes and the cathode, improving the display quality and yield of top-emission OLED devices.
Implementation Method 1
scanning auxiliary electrode regions by laser, so that the gas generation layer is decomposed under laser irradiation to release gas
Implementation Method 2
the gas generation layer is decomposed under laser irradiation to release gas
Data Source
AI summary
A method for manufacturing an organic light-emitting diode (OLED) device includes: forming auxiliary electrodes (2) on a resin layer (1) of an OLED substrate; forming a gas generation layer (4) on the auxiliary electrodes (2); forming an organic light-emitting layer (6) on the gas generation layer (4); placing a receptor substrate (12) on the organic light-emitting layer (6) and scanning auxiliary electrode regions (22) by laser, so that the gas generation layer (4) is decomposed under laser irradiation to release gas, and hence the organic light-emitting layer (6) in the auxiliary electrode regions (22) is transferred to the receptor substrate (12); removing the receptor substrate (12); and forming a cathode (7) on the auxiliary electrodes. The manufacturing process can effectively reduce poor contact between the auxiliary electrodes and the cathode.