Organic EL Display Pad Corrosion Protection
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Solution Overview
Problem
The top-emission type organic electro-luminescence display devices face challenges in light efficiency due to limited transmittance of electrode materials and are prone to corrosion of exposed pad portions, leading to reliability issues and defective pixels.
Innovation Solution
The solution involves forming thin film transistors (TFTs) and organic light-emitting diodes on separate substrates with corrosion-resistant conductive patterns for the pad portions, ensuring they are not exposed externally, and using a method that includes specific conductive materials like indium tin oxide (ITO) and indium zinc oxide (IZO) for the gate and data pads, along with a link line to connect the pads, preventing corrosion and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a top-emission type organic electro-luminescence display device is used to improve aperture ratio and ease of TFT design, then the aperture ratio is improved, but the transmittance of electrode materials is limited reducing light efficiency
Solution Approach 1:
The patent employs composite electrode structures combining transparent conductive materials (such as ITO, IZO) with reflective materials (such as Al, Ag, Mo) in multi-layer configurations. This composite approach allows the electrode to simultaneously provide electrical conductivity, optical transparency for light emission, and reflectivity for light extraction enhancement, thereby resolving the transmittance limitation in top-emission devices while maintaining high aperture ratios
2Ease of operation
If pad portions are exposed to the outside for signal reception, then ease of connection is improved, but corrosion by external oxygen and moisture occurs leading to reliability issues
Solution Approach 1:
The patent introduces an inert atmosphere barrier by forming encapsulation layers (such as N-type doped semiconductor layers or insulating layers) over the exposed pad portions. These layers create a protective environment that prevents direct contact between the metal pad and external oxygen/moisture, thereby eliminating corrosion while maintaining electrical connection functionality
Solution Approach 2:
The patent introduces intermediate protective layers (encapsulation layers, passivation layers) between the metal pad portion and the external environment. These intermediary layers serve as barriers that prevent harmful substances (oxygen, moisture) from reaching the pad, thereby protecting against corrosion while allowing electrical signals to pass through via contact holes or conductive pathways
3Power
If metal pad portions are used for signal reception, then electrical conductivity is improved, but corrosion increases contact resistance generating defective pixels
Solution Approach 1:
The patent employs composite pad structures combining metal layers (for low resistance) with protective encapsulation layers (for corrosion resistance). The metal layer provides excellent electrical conductivity while the overlying encapsulation layer prevents corrosion, thereby maintaining stable contact resistance and eliminating defective pixels caused by corrosion-induced resistance increases
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 improves light efficiency and reliability by preventing corrosion of the pad portions, reducing defective pixels, and enhancing the production yield by managing error rates effectively.
Implementation Method 1
uses a phenomenon that carriers such as electrons and holes create electron-hole pairs or carriers are excited to a higher energy state and then fall down to a ground state, which is a stable state, inside a semiconductor to generate light
Data Source
AI summary
Provided is an organic electro-luminescence display device. Because TFTs and organic light-emitting diode devices are formed on two different substrates, respectively, and the two substrates are attached to each other, so that productivity improves and manufacturing costs can be reduced. Also, because a pad portion exposed to the outside is formed using a conductive layer having corrosion resistance, corrosion of the pad portion is prevented, and thus an organic electro-luminescence display device having improved reliability can be provided.