OLED Pad Conductive Layer Protrusions Reduce Contact Resistance
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Solution Overview
Problem
Conventional organic light-emitting display devices face challenges with thick conductive layers, as they are difficult to etch and require strong acids, leading to increased contact and surface resistance, which degrades device reliability and poses handling hazards.
Innovation Solution
The implementation of a conductive layer with protrusions and recesses on its surface, or on underlying layers, to increase contact area and reduce resistance, allowing for a thinner conductive layer without the need for strong acids, and a semiconductor layer with corresponding patterns to enhance connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive layer thickness is increased to reduce contact resistance, then electrical conductivity improves, but etching difficulty increases and strong acids are required which pose handling hazards
Solution Approach 1:
The patent transitions from varying conductive layer thickness (one-dimensional solution) to creating protrusions and recesses on the conductive layer surface (three-dimensional solution). This dimensional change allows achieving lower contact resistance through increased surface area and better contact geometry without increasing the overall layer thickness, thereby avoiding the need for strong acids and associated handling hazards.
Solution Approach 2:
The patent applies local quality by creating protrusions at specific locations on the conductive layer that contact the drive IC chip bumps. These localized protrusions concentrate the conductive material where contact is needed, achieving low contact resistance at the contact points without requiring the entire conductive layer to be thick, thus avoiding the need for strong acids.
2Reliability
If the conductive layer thickness is increased to reduce surface resistance, then electrical conductivity improves, but manufacturing complexity increases due to etching difficulties
Solution Approach 1:
Instead of increasing conductive layer thickness to reduce surface resistance, the patent creates a three-dimensional surface structure with protrusions and recesses. This dimensional approach reduces surface resistance by increasing the effective contact area and improving current distribution without making the etching process more difficult.
Solution Approach 2:
The patent changes the geometric parameters of the conductive layer by introducing protrusions with specific dimensions (e.g., 1-10 μm height) rather than changing the overall layer thickness. This parameter change achieves the desired electrical properties while keeping the conductive layer thin and easy to manufacture.
3Object-affected harmful factors
If the conductive layer is made thinner to improve etching safety, then handling safety improves, but contact resistance increases due to film dispersion
Solution Approach 1:
The patent resolves this contradiction by moving from a thin flat conductive layer to a thin layer with three-dimensional protrusions. The protrusions increase the contact area and improve current pathways locally, achieving low contact resistance despite the overall thinness of the layer, thus maintaining both safety and electrical performance.
Solution Approach 2:
The patent applies local quality by concentrating conductive material in protrusions at the contact regions. This localized concentration of conductive material ensures low contact resistance at critical points while keeping the overall layer thin for safety, eliminating the need for strong acids.
4Reliability
If protrusions and recesses are formed on the conductive layer to increase contact area, then contact resistance reduces, but device complexity increases
Solution Approach 1:
The patent segments the conductive layer into multiple protrusion elements rather than using a continuous flat layer. This segmentation increases the contact area with the drive IC chip bumps, achieving lower contact resistance. The segmented structure is simple to implement using standard photolithography and etching processes.
Solution Approach 2:
The patent changes geometric parameters (protrusion height, width, spacing) to optimize contact resistance while maintaining manufacturing simplicity. By carefully selecting these parameters within reasonable ranges, the patent achieves low contact resistance without significantly increasing device complexity.
Data Source
AI summary
Provided is an organic light-emitting display device. The organic light-emitting display device includes: a substrate; a buffer layer formed on the substrate; a gate insulating layer formed on the buffer layer; a conductive layer formed on the gate insulating layer; and a pixel defined layer exposing a portion of the conductive layer to form a pad portion connected to bumps of a drive integrated circuit (IC) chip, wherein protrusions and recesses are formed on a surface of the conductive layer.