Display Pad Composite Layer for Oxidation Resistance
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Solution Overview
Problem
Display devices face challenges in preventing defects in the pad unit of the peripheral area while maintaining high-quality image performance in the display area, particularly due to issues with the electrical conductivity and durability of the pad layers.
Innovation Solution
The display device incorporates a substrate with a thin-film transistor, a display element, an interlayer insulating layer, a conductive layer, and a second conductive layer made of titanium (Ti) that covers the pad, enhancing electrical conductivity and corrosion resistance, and a connection electrode connecting the thin-film transistor to the pixel electrode, ensuring reliable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pad layer is arranged in the peripheral area to enable electrical connections, then electrical conductivity is improved, but the pad unit becomes susceptible to oxidation and corrosion, reducing reliability
Solution Approach 1:
The pad unit employs a composite structure consisting of a first pad layer (highly conductive metal such as copper or aluminum) and a second pad layer (oxidation-resistant metal such as titanium nitride or tungsten). This composite material approach allows the first pad layer to provide excellent electrical conductivity while the second pad layer protects against oxidation and corrosion, thereby resolving the contradiction between electrical conductivity and oxidation resistance.
Solution Approach 2:
Different regions of the pad unit are assigned different material properties: the first pad layer is optimized for electrical conductivity with low resistivity, while the second pad layer is optimized for chemical stability and oxidation resistance. This local differentiation of material qualities allows each layer to perform its specific function optimally, addressing both the conductivity and reliability requirements simultaneously.
2Reliability
If the pad layer uses highly conductive materials, then electrical conductivity is improved, but the resistance to oxidation and corrosion deteriorates
Solution Approach 1:
The patent utilizes a composite material system where the first pad layer comprises highly conductive metals (copper, aluminum, or silver) that provide excellent electrical conductivity, while the second pad layer comprises oxidation-resistant materials (titanium nitride, tungsten, or molybdenum) that protect the conductive layer from corrosion. This composite structure resolves the contradiction by combining materials with complementary properties.
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 prevents defects in the pad unit, maintains high-quality image performance, and improves the reliability of the display device by ensuring robust electrical connections and resistance to oxidation.
Implementation Method 1
a second conductive layer made of titanium (Ti) that covers the pad, enhancing electrical conductivity and corrosion resistance
Implementation Method 2
a second conductive layer made of titanium (Ti) that covers the pad, enhancing electrical conductivity and corrosion resistance
Data Source
AI summary
A display device includes a substrate including a display area and a peripheral area outside the display area, a thin-film transistor arranged in the display area, a display element arranged in the display area, an interlayer insulating layer covering the thin-film transistor, a conductive layer arranged above the interlayer insulating layer, a first insulating layer covering the conductive layer, a pad arranged in the peripheral area, and a second conductive layer covering a central portion of the pad. The pad is connected to a connection line through a contact hole, and the connection line is arranged on a same first layer as a gate electrode of the thin-film transistor. A side surface of the pad is covered by the first insulating layer or the second conductive layer.