Organic Light-Emitting Display Electrode Segmentation
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Solution Overview
Problem
The existing organic light-emitting display apparatus faces challenges in efficiently manufacturing large-sized panels due to high sheet resistance of the cathode and the inability to effectively use fine metal masks for patterning, which affects transmittance and resistance.
Innovation Solution
The apparatus includes a substrate with pixels having distinct regions for light emission and transmission, where the second electrode is formed with reduced thickness in the transmission region and the third electrode is thicker, both being in contact, and auxiliary layers are used to expose these regions without a separate patterning mask, simplifying the process and improving transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If transparent/translucent metal is used for the cathode, then the display area can be fully covered, but the sheet resistance becomes high and large-sized panels cannot be efficiently manufactured
Solution Approach 1:
The cathode is divided into multiple separate electrode patterns rather than using a single continuous transparent metal layer. This segmentation allows each electrode to be optimized for conductivity while maintaining overall coverage, resolving the contradiction between full area coverage and low sheet resistance.
Solution Approach 2:
Different regions of the cathode structure are given different properties - the electrode patterns have higher metal content for conductivity, while the inter-electrode regions maintain transparency. This local differentiation allows simultaneous optimization of both coverage area and electrical resistance characteristics.
2Reliability
If opaque metal is used for the cathode, then sheet resistance is reduced, but fine metal masks cannot be effectively used and transmission regions are blocked
Solution Approach 1:
The cathode is segmented into discrete electrode patterns with transparent spacing between them. This allows the use of opaque metal material for the electrodes themselves (achieving low resistance) while maintaining light transmission through the transparent regions, eliminating the need for fine metal masks.
Solution Approach 2:
The cathode structure exhibits spatially varying properties - opaque metal regions provide electrical conductivity where needed, while transparent regions allow light transmission. This local quality differentiation resolves the contradiction between using opaque metal for low resistance and maintaining light transmission for display functionality.
3Manufacturing precision
If a fine metal mask is used for conventional organic material patterning, then opening patterns can be formed, but the process becomes complex and cannot be effectively used for large-sized panels
Solution Approach 1:
The fine metal mask step is completely removed from the manufacturing process. Instead of using a mask to define patterns, the electrode patterns are directly formed through selective deposition or printing methods, extracting the problematic masking step while maintaining pattern formation capability.
Solution Approach 2:
The patterning process becomes self-defining through the inherent properties of the deposition method or the self-organizing behavior of the material, eliminating the need for external mask guidance. This self-service approach simplifies the process while maintaining manufacturing precision.
Data Source
AI summary
An organic light-emitting display apparatus includes: a substrate; pixels defined on the substrate, where each pixel includes a first region including a light-emitting region and a second region including a transmission region; a third region defined on the substrate disposed between the pixels; first electrodes disposed in the pixels on the substrate, respectively, where each first electrode is disposed in the first region of a corresponding pixel; an organic emission layer disposed to cover the first electrodes; a first auxiliary layer disposed on the organic emission layer in the second region and which exposes the first region; a second electrode disposed on the organic emission layer in the first region; a second auxiliary layer disposed in the first and second regions and which exposes the third region; and a third electrode disposed in the third region and in contact with the second electrode.