OLED Pad Electrode Corrosion Resistance via Insulation Pattern
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Solution Overview
Problem
Existing organic light-emitting display devices face issues with resistance dispersion and corrosion in large-size panels, leading to degraded display quality and reliability, particularly due to the exposure of metal electrodes which increases contact resistance and reduces corrosion resistance.
Innovation Solution
The organic light-emitting display device incorporates an electrode pattern formed on the same layer as the pad top electrode, with an insulation pattern covering the electrode pattern's surface and a pad bottom electrode made of a material with better corrosion resistance, connected to a driver IC via conductive balls through openings in the pad top electrode, improving resistance dispersion and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal electrodes are exposed in large-size panels, then electrical connection is achieved, but contact resistance increases and corrosion resistance decreases
Solution Approach 1:
The patent transitions from a two-dimensional exposed electrode surface to a three-dimensional structure by forming openings (through-holes) in the pad top electrode that expose the pad bottom electrode. This vertical dimension allows conductive balls to make contact with the corrosion-resistant pad bottom electrode while the pad top electrode provides overall structural support and connection, thereby reducing contact resistance without compromising corrosion resistance.
Solution Approach 2:
The pad electrode structure employs a composite configuration combining pad top electrode and pad bottom electrode made of different materials with complementary properties. The pad top electrode provides structural integrity and general electrical connection, while the pad bottom electrode offers superior corrosion resistance and low contact resistance where direct contact with conductive balls occurs, achieving both requirements simultaneously.
2Ease of manufacture
If pad electrode structure is simplified, then manufacturing is easier, but resistance dispersion and corrosion issues worsen in large-size panels
Solution Approach 1:
The pad electrode is segmented into multiple functional components: pad top electrode, pad bottom electrode, openings, and electrode pattern. This segmentation allows each component to perform its specific function optimally - the pad top electrode provides structural support, the pad bottom electrode ensures low resistance contact, and the openings enable direct connection to conductive balls, thereby achieving reliable electrical connection without excessive manufacturing complexity.
Solution Approach 2:
The pad bottom electrode is nested within the pad top electrode structure, with openings formed through the pad top electrode to expose portions of the pad bottom electrode. This nested configuration allows the corrosion-resistant pad bottom electrode to be protected by the pad top electrode while still providing direct contact points for conductive balls, achieving both manufacturing feasibility and electrical performance.
3Duration of action of stationary object
If electrode corrosion is prevented, then device lifetime increases, but manufacturing complexity increases
Solution Approach 1:
The corrosion protection strategy applies local quality by providing different levels of protection to different parts of the electrode structure. The pad bottom electrode, which is most vulnerable to corrosion at contact points, is made of corrosion-resistant material and exposed through openings. The pad top electrode provides general protection, while the electrode pattern and insulation pattern provide localized protection in specific areas, achieving effective corrosion prevention without unnecessary overall complexity.
Data Source
AI summary
An OLED device includes a thin film transistor including an active layer, a gate bottom electrode, a gate top electrode, an insulating layer covering the gate electrode, and a source electrode and a drain electrode on the insulating layer contacting the active layer; an organic light-emitting device electrically connected to the thin film transistor and including a sequentially stacked pixel electrode, on the same layer as the gate bottom electrode, emissive layer, and, opposite electrode, a pad bottom electrode on the same layer as the gate bottom electrode and a pad top electrode pattern on the same layer as the gate top electrode, the pad top electrode pattern including openings exposing the pad bottom electrode, and an insulation pattern covering the upper surface of the pad top electrode pattern on the same layer as the insulating layer, on an upper surface of the pad bottom electrode.