Display Panel PCB Bonding With Underfill and Lead Alignment
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Solution Overview
Problem
Current display devices face challenges in achieving strong adhesion between the display panel and the printed circuit board, which can lead to reliability issues and potential failures in the connection of signal lines.
Innovation Solution
The implementation of a display device design that includes specific lead align marks and signal lines on both the circuit and panel pads, allowing for ultrasonic bonding and the use of an anisotropic conductive film, along with an underfill resin to enhance the mechanical and electrical connection between the printed circuit board and the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic bonding process is used to bond leads to pads, then electrical connection is achieved, but adhesion strength between display panel and printed circuit board is insufficient
Solution Approach 1:
The patent introduces an underfill resin as an intermediary substance between the display panel and printed circuit board. This resin fills the gap between the PCB and panel, providing enhanced mechanical adhesion and structural support beyond what ultrasonic bonding alone can achieve, thereby resolving the adhesion strength insufficiency without significantly increasing process complexity
Solution Approach 2:
The patent employs a composite bonding approach combining ultrasonic bonding (mechanical/electrical connection) with underfill resin (chemical/adhesive connection). This composite method integrates two different bonding mechanisms to achieve both electrical connectivity and strong mechanical adhesion, effectively addressing the limitation of using ultrasonic bonding alone
2Reliability
If simple pad connection is used, then manufacturing is easy, but electrical connectivity and signal transmission reliability are compromised
Solution Approach 1:
The patent incorporates lead align marks with through-patterns during the PCB design and manufacturing stage. These pre-designed alignment features ensure accurate positioning of leads relative to pads during assembly, enabling reliable electrical connectivity while maintaining manufacturing efficiency through automated alignment processes
Solution Approach 2:
The underfill resin serves as a mediator that not only enhances adhesion but also provides mechanical support and stress distribution across the connection interface. This intermediary substance protects the electrical connections from mechanical stresses and environmental factors, improving long-term reliability without complicating the manufacturing process
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 solution improves the adhesion and electrical connectivity between the display panel and the printed circuit board, enhancing the overall reliability and stability of the display device by ensuring a robust mechanical bond and efficient signal transmission.
Implementation Method 1
a coupling member disposed between the first lead signal line and the first panel signal line, where the coupling member includes an anisotropic conductive film, and the first lead signal line and the first panel signal line may be electrically connected to each other by the anisotropic conductive film
Implementation Method 2
The bonding may be performed by an ultrasonic bonding process
Data Source
AI summary
A display device includes a base substrate in which a display area and a pad area disposed around the display area are defined, a plurality of panel pads disposed on the pad area of the base substrate, and a printed circuit board attached to the pad area of the base substrate. The printed circuit board includes a plurality of circuit pads, the plurality of circuit pads include a first lead align mark, and the first lead align mark includes a plurality of first patterns passing through the first lead align mark from a surface of the first lead align mark in a thickness direction.