Composite Wiring Structure for OLED Display Signal Integrity
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Solution Overview
Problem
In organic electro luminescence displays, the increased resistance of wiring due to longer lengths and finer dimensions leads to signal distortion and transmission delays, particularly in active matrix systems, which affects image quality, and the use of low resistance materials like aluminum is limited by thermal stress and hillock formation.
Innovation Solution
A display unit with divided wiring, where a crossing portion and a main portion are formed in layers with a conductive connection through an insulating film, using a first layer of low resistance metal and a second layer of higher melting point material, ensuring direct contact and reduced resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low resistance material such as aluminum is used for wiring, then wiring resistance is reduced, but thermal stress causes hillock formation and deterioration of insulation quality
Solution Approach 1:
The patent uses a composite wiring structure consisting of a first wiring layer (aluminum or aluminum alloy for low resistance) and a second wiring layer (refractory metal with high melting point for thermal stability). This composite structure combines the advantages of both materials: the aluminum layer provides low resistance while the refractory metal layer prevents hillock formation and protects against thermal stress during manufacturing processes.
2Area of stationary object
If wiring length is increased for larger display size, then display area is expanded, but wiring resistance increases causing signal distortion and transmission delay
Solution Approach 1:
The patent employs a composite wiring structure with an aluminum-based first wiring layer and a refractory metal second wiring layer. This composite structure reduces overall wiring resistance compared to using refractory metal alone, enabling larger display sizes while maintaining signal quality and reducing transmission delays.
Solution Approach 2:
The patent transitions from a single-layer wiring structure to a multi-layer wiring structure by stacking the first wiring layer and the second wiring layer vertically. This dimensional change allows the current to flow through both layers in parallel, effectively reducing resistance while accommodating larger display areas.
3Object-affected harmful factors
If refractory metal is used for wiring to resist thermal stress, then thermal stability is improved, but wiring resistance increases causing signal distortion
Solution Approach 1:
The patent creates a composite wiring system where the refractory metal second wiring layer provides thermal stability and resistance to hillock formation, while the aluminum-based first wiring layer provides low electrical resistance. The combination allows the wiring to withstand thermal stress during manufacturing while maintaining low resistance for signal integrity.
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 reduces wiring resistance, minimizing signal distortion and transmission delays, thereby improving image quality and simplifying the manufacturing process.
Implementation Method 1
at least one of them includes a first layer and a second layer stacked in order from the insulating substrate side. The second layer is in direct contact with the first layer
Data Source
AI summary
A display unit includes, on an insulating substrate, a plurality of wirings formed to extend in different directions, a thin-film transistor, and a display element. At least one of the plurality of wirings is a divided wiring having a crossing portion formed at an intersection with the other of the plurality of wirings, and a main portion which is formed in a layer same as the other of the plurality of wirings with an insulating film in between and which is electrically connected to the crossing portion via an conductive connection provided in the insulating film. At least one of the main portion and the crossing portion includes a first layer and a second layer stacked in order from the insulating substrate side, the second layer being in direct contact with the first layer and made of a material of a higher melting point than the first layer.