Display Device Light Absorption Layer for Precision Organic Layer Removal
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Solution Overview
Problem
The existing methods for manufacturing display devices with organic electroluminescent elements face challenges in precisely removing the organic layer from auxiliary wiring, leading to misalignment and increased production costs, which reduces yield and productivity.
Innovation Solution
A method involving a light absorption layer with a higher absorption coefficient than the lower electrode is used in the auxiliary wiring, allowing for selective removal of the organic layer through laser irradiation without misalignment, as the laser light is absorbed and converted to heat in this layer, rather than the lower electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser irradiation is used to remove the organic layer on auxiliary wiring, then the organic layer can be selectively removed, but misalignment between the laser irradiation and auxiliary wiring occurs reducing yield
Solution Approach 1:
The auxiliary wiring is designed with a light absorption layer having a higher light absorption coefficient than the lower electrode. This creates local quality differentiation where only the auxiliary wiring absorbs laser light and converts it to heat for organic layer removal, while the lower electrode does not. This resolves the misalignment issue by making the auxiliary wiring itself the target of laser absorption rather than relying on precise alignment with external structures.
2Manufacturing precision
If masks are used for laser irradiation alignment, then the organic layer can be selectively removed, but production cost increases
Solution Approach 1:
The auxiliary wiring's light absorption layer serves a dual function: it provides electrical connectivity and acts as the selective target for laser irradiation. The auxiliary wiring itself 'services' the alignment function that would otherwise require external masks, eliminating the need for additional alignment components and reducing production cost.
3Manufacturing precision
If laser alignment operations are performed, then the organic layer can be selectively removed, but operation time increases reducing productivity
Solution Approach 1:
The light absorption layer is pre-formed as part of the auxiliary wiring structure before the organic layer deposition. This preliminary action embeds the alignment reference directly into the wiring structure, eliminating the need for subsequent alignment operations and reducing operation time to improve productivity.
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 approach enables high-precision removal of the organic layer on the auxiliary wiring, improving yield and productivity by preventing voltage drops in the upper electrode and reducing production costs by eliminating the need for expensive masks and complex alignment processes.
Implementation Method 1
a light absorption layer formed from an electrically conductive material having a light absorption coefficient higher than that of the lower electrode
Implementation Method 2
the organic layer portion on the auxiliary wiring is selectively ablated
Implementation Method 3
An organic electroluminescent element taking advantage of electroluminescence (EL) of an organic material
Data Source
AI summary
A display device and a method for manufacturing the display device are provided. The display device includes an organic layer on an auxiliary wiring is removed with high precision by one operation and, thereby, the yield and the productivity are improved. A lower electrode is formed by patterning in each pixel on a substrate. An auxiliary wiring including a light absorption layer is formed between individual pixels. An organic layer is formed on the substrate while covering the lower electrodes. Laser irradiation is conducted from the organic layer side, the laser light is converted to heat in the light absorption layer exposed at a portion under the organic layer, and the organic layer portion above the light absorption layer is removed selectively. An upper electrode is formed on the organic layer and is connected to the light absorption layer portion of the auxiliary wiring.