Polymer Conductive Patterns for Flexible Display Bonding
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Solution Overview
Problem
Flexible display panels experience deformation and cracking during bonding with driving chips, leading to poor bonding impedance due to the deformation of the flexible substrate and potential oxidation or corrosion of metal pads exposed by cracked transparent conductive layers.
Innovation Solution
Incorporating polymer conductive patterns on the pads, which provide ductility to cushion stress during bonding, preventing cracking and damage to the conductive layers and maintaining the integrity of the bonding interface between the display panel and the driving chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible substrate is used in the display panel, then flexibility and portability are improved, but the substrate deforms during bonding causing cracks in the transparent conductive layer
Solution Approach 1:
The patent changes the material parameter of the conductive layer from traditional transparent conductive oxide (TCO) to polymer conductive material. This material substitution provides ductility to the conductive layer, allowing it to accommodate the deformation of the flexible substrate during bonding without cracking, thus resolving the contradiction between flexibility and bonding reliability
Solution Approach 2:
The patent employs a composite structure where polymer conductive material is combined with the flexible substrate and other display layers. The polymer conductive material serves as a ductile intermediate layer that can deform with the flexible substrate while maintaining electrical conductivity, preventing crack formation in the bonding region
2Device complexity
If the transparent conductive layer is cracked during bonding, then manufacturing complexity is reduced, but the metal pads are exposed leading to oxidation and corrosion
Solution Approach 1:
The patent applies beforehand cushioning by using polymer conductive material that inherently accommodates deformation during bonding. This material acts as a protective cushion that prevents crack formation in advance, thereby preventing exposure of metal pads to oxidation and corrosion before such damage can occur
Solution Approach 2:
By changing the material parameter from brittle TCO to ductile polymer conductive material, the patent fundamentally alters the mechanical behavior of the conductive layer. This parameter change ensures the material can withstand bonding deformation without cracking, thus preventing pad exposure and subsequent oxidation or corrosion
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
The use of polymer conductive patterns enhances bonding yield by preventing damage to the conductive layers and protecting the metal pads from oxidation or corrosion, thereby improving the electrical connection between the driving chip and the display panel.
Implementation Method 1
Since the polymer conductive material has favorable ductility, the conductive patterns located above the pads can be prevented from being cracked or damaged when the display panel and the driving chip are bonded
Data Source
AI summary
A display device includes a display panel and at least one driving chip. The display panel has a display region and a non-display region and includes a pixel array, a plurality of pads, a passivation layer, and a plurality of conductive patterns. The pixel array is located in the display region. The pads are located in the non-display region and electrically connected to the pixel array. The passivation layer is located on the pads and has a plurality of through holes. Each of the conductive patterns covers one of the pads and is electrically connected to the pad through at least one of the through holes. A material of the conductive patterns includes a polymer conductive material. The driving chip is located on the display panel and electrically connected to the pads of the display panel.