Light-Emitting Device Auxiliary Interconnect Voltage Control
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Solution Overview
Problem
Existing light-emitting devices with high resistance second electrodes face challenges in achieving both high aperture ratio and controlled voltage drop, as low resistance auxiliary interconnects block light and increasing their width or reducing their size compromises either aperture ratio or voltage control.
Innovation Solution
The design includes auxiliary interconnects formed of lower resistivity material, strategically placed between certain groups of light-emitting elements, extending in the direction of the first electrode, and not between every group, allowing for increased aperture ratio and reduced resistance without compromising voltage control, and simplifies the production process by eliminating the need for contact holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary interconnects are formed of low resistance material to control voltage drop, then voltage uniformity is improved, but aperture ratio is reduced due to light blocking
Solution Approach 1:
The patent applies partial action by forming auxiliary interconnects only in specific gaps between certain element groups rather than in all gaps. This selective placement provides sufficient voltage control in critical areas while minimizing light blocking, thus achieving voltage uniformity without excessively compromising aperture ratio
Solution Approach 2:
The patent implements local quality by making the second electrode and auxiliary interconnects light-transmissive in the light extraction region. This allows the interconnects to maintain their electrical function while being transparent to light, thereby controlling voltage drop without reducing aperture ratio
2Area of stationary object
If width of auxiliary interconnects is reduced to maintain high aperture ratio, then aperture ratio is improved, but resistance value increases and voltage drop control becomes insufficient
Solution Approach 1:
The patent uses composite material structure where the second electrode and auxiliary interconnects are formed of a light-transmissive conductive material that combines both light transparency and electrical conductivity. This composite approach allows maintaining both high aperture ratio and low resistance simultaneously
Solution Approach 2:
The patent applies partial action by selectively placing auxiliary interconnects only where needed for voltage control, rather than forming them in all gaps. This reduces the total blocking area while providing sufficient voltage uniformity in critical regions
3Reliability
If margin region is provided between auxiliary interconnects and light-emitting elements to prevent overlap, then manufacturing reliability is improved, but both aperture ratio and voltage drop control become more difficult
Solution Approach 1:
The patent implements local quality by making the margin region light-transmissive. This allows the margin region to serve its protective function while not blocking light, thereby maintaining high aperture ratio even with the presence of margin regions
Solution Approach 2:
The patent uses light-transmissive conductive materials for the second electrode and auxiliary interconnects that extend into margin regions. This composite approach allows interconnects to maintain electrical continuity while being transparent to light, reducing the impact of margin regions on aperture ratio
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 configuration enhances the aperture ratio and reduces the resistance of auxiliary interconnects, leading to improved light emission efficiency and longer device lifespan by optimizing electrical energy supply and minimizing voltage drop across the second electrode.
Implementation Method 1
The auxiliary interconnect is formed of a material having a resistivity lower than the resistivity of the second electrode and is electrically connected to the second electrode of each light-emitting element
Implementation Method 2
Each light-emitting element has a structure such that a light-emitting layer lies between a first electrode and a second electrode
Data Source
AI summary
A light-emitting device includes an element array portion and an auxiliary interconnect. The element array portion includes a plurality of element groups. Each element group includes a plurality of light-emitting elements arranged in a first direction. Each light-emitting element has a structure such that a light-emitting layer lies between a first electrode and a second electrode. The element groups are arranged in a second direction perpendicular to the first direction. The auxiliary interconnect is formed of a material having a resistivity lower than the resistivity of the second electrode and is electrically connected to the second electrode of each light-emitting element. The plurality of element groups include a first element group and a second element group adjacent to each other and a third element group adjacent to the opposite side of the second element group from the first element group. The auxiliary interconnect extends in the first direction in a gap between the first element group and the second element group but is not formed in a gap between the second element group and the third element group.