Organic Light Emitting Display Pad Electrode Silver Defect Control
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Solution Overview
Problem
Existing organic light emitting display devices face challenges in achieving high display quality due to issues such as particle defects from silver reprecipitation during the manufacturing process, which can lead to dark spots and reduced light emission efficiency.
Innovation Solution
The organic light emitting display device incorporates a semi-transmissive metal layer with transparent conductive oxide layers and uses a third insulating layer made of organic material to cover the source and drain electrodes, preventing exposure to silver ions during etching and reducing particle defects. Additionally, a half-tone mask is employed to protect the pad layer during pixel electrode patterning, minimizing silver reprecipitation and dark spot formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional manufacturing process is used for organic light emitting display devices, then the manufacturing process is simpler, but particle defects occur due to silver reprecipitation during etching, leading to dark spots and reduced light emission efficiency
Solution Approach 1:
The pad layer is formed with a transparent conductive oxide material before the pixel electrode patterning process. This preliminary formation of the pad layer with appropriate material selection prevents silver reprecipitation during subsequent etching operations, thereby preventing particle defects and dark spots before they can occur
Solution Approach 2:
The transparent conductive oxide pad layer acts as an intermediary layer between the source/drain electrodes and the pixel electrode structure. This intermediary layer prevents direct exposure to silver ions during etching, thereby mediating the harmful interaction that causes silver reprecipitation and particle defects
2Productivity
If the number of masks is reduced in the manufacturing process, then productivity increases, but manufacturing precision may be compromised
Solution Approach 1:
The manufacturing process merges multiple functions into the pad layer formation step. The pad layer simultaneously serves as an electrode structure, a protective layer against silver reprecipitation, and a conductive element, thereby combining multiple requirements into a single process step that reduces total mask operations while maintaining precision
Data Source
AI summary
An organic light emitting display device including a thin film transistor including an active layer, a gate electrode, a source electrode, a drain electrode, a source electrode top layer on the source electrode and a drain electrode top layer on the drain electrode, a first insulating layer between the active layer and the gate electrode, and a second insulating layer between the gate electrode and the source and drain electrodes; a pad electrode including a first pad layer at the same level as the source electrode and a second pad layer on the first pad layer and at the same level as the source and drain electrode top layers; a third insulating layer covering end portions of the source, drain, and pad electrodes and including an organic insulating layer; and a pixel electrode in an opening formed in the third insulating layer and including a semi-transmissive metal layer.