Organic Functional Device Shunt Structure for Current Uniformity
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Solution Overview
Problem
Organic functional devices, such as OLEDs, suffer from non-uniform current distribution due to high surface resistance in transparent electrode layers, leading to non-uniform light output and voltage variations across the device, which existing shunting structures cannot fully address without damaging the sensitive organic functional layer.
Innovation Solution
The implementation of a substrate shunt structure before the organic functional layer is formed, allowing for the deposition of second electrode shunting structures that connect with the substrate shunt, creating a continuous conductive grid to ensure uniform current distribution without damaging the organic layer, using techniques like shadow masking to limit structure complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If highly conductive shunting structures are provided to improve current distribution uniformity, then current distribution uniformity is improved, but the electrode layer becomes opaque and cannot be deposited on large coherent portions
Solution Approach 1:
The shunting structure is divided into multiple discrete segments (first shunting structures and second shunting structures) rather than a continuous pattern. This segmentation allows the conductive material to be deposited in isolated regions through shadow masking, maintaining transparency in the electrode layer while providing sufficient shunting paths to improve current distribution uniformity across the device area.
2Device complexity
If complex patterns are formed using photolithography and high deposition temperatures, then shunting structure complexity is improved, but the organic functional layer is damaged
Solution Approach 1:
The first shunting structures are formed on the substrate before the organic functional layer is deposited. This preliminary action allows the use of more aggressive deposition techniques and higher temperatures during the first shunting structure formation, without risking damage to the organic layer, which is not yet present. The organic functional layer is then deposited, followed by formation of additional shunting structures using gentler methods that are compatible with the sensitive organic material.
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 enhances current distribution uniformity in organic functional devices, achieving nearly optimal performance comparable to unrestricted deposition methods while protecting the sensitive organic layer, and allows for individually controllable voltage across each organic functional layer in stacked devices.
Implementation Method 1
A possible method for applying shunting structures without damaging the organic functional layer is to use a shadow mask and evaporate a highly conductive substance, such as a metal or carbon through openings in the mask.
Data Source
AI summary
An organic functional device (1; 40; 50) comprising a substrate (2) having a first electrode layer (3) and at least a first substrate shunt structure (6), at least a first organic functional layer (7) provided on top of the first electrode layer (3), a second, transparent electrode layer (8) arranged on top of the first organic functional layer (7). The organic functional device further comprises a plurality of mutually spaced apart second electrode shunting structures (9a-d) which are each in electrical contact with the second electrode layer (8) and with the first substrate shunt structure (6).