Conductive Ball Adhesive Film for Display Pad Bonding Reliability
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Solution Overview
Problem
Existing display devices face reliability issues due to inadequate adhesion between the circuit board and the display panel, particularly in the non-display regions where signal pads and driving pads are located, leading to potential electrical signal transmission failures.
Innovation Solution
An adhesive film with a base resin and conductive balls is used between the circuit board and the display panel, ensuring that the conductive balls maintain a consistent diameter difference of less than 25% and are strategically positioned to fill the gap between driving pads, enhancing adhesion strength and eliminating the need for additional gap-filling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive film is used between the circuit board and display panel, then adhesion strength is improved, but the reliability of electrical signal transmission deteriorates due to inadequate adhesion in non-display regions
Solution Approach 1:
The adhesive film is formulated as a composite material containing conductive balls dispersed in the adhesive matrix. This composite structure provides both mechanical adhesion strength and electrical conductivity, allowing the same material to simultaneously improve bonding and maintain signal transmission reliability in the non-display regions.
Solution Approach 2:
The adhesive film serves multiple functions: it provides mechanical bonding between the circuit board and display panel, fills gaps in the non-display regions, and conducts electrical signals. This multi-functionality eliminates the need for separate adhesive and under-fill materials, ensuring both structural integrity and electrical reliability.
2Reliability
If additional gap-filling processes are implemented, then adhesion in non-display regions is improved, but process time and manufacturing complexity increase
Solution Approach 1:
The gap-filling function and adhesive bonding function are merged into a single adhesive film application process. The conductive balls within the adhesive film naturally fill the gaps between the circuit board and display panel in the non-display regions, eliminating the need for separate under-fill or gap-filling processes and reducing overall manufacturing time.
Solution Approach 2:
The adhesive film is pre-formulated with conductive balls and applied in advance during the bonding process. This preliminary action ensures that gaps are filled and adhesion is established simultaneously before final assembly, preventing the need for subsequent corrective processes.
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 improves the reliability of the display device by ensuring strong adhesion between the circuit board and the display panel, reducing process time and costs, and maintaining electrical connectivity without additional under-fill processes.
Implementation Method 1
an adhesive film disposed between the circuit board and the display panel and overlapped with the first and second signal pads. The adhesive film includes a base resin and a plurality of conductive balls dispersed in the base resin
Data Source
AI summary
A display device includes a display panel including a first signal pad and a second signal pad, a circuit board overlapped with the first and second signal pads, and an adhesive film overlapped with the first and second signal pads and disposed between the circuit board and the display panel. The adhesive film includes a base resin and a plurality of conductive balls dispersed in the base resin. The circuit board includes a first driving pad and a second driving pad. The first and second driving pads protrude toward the adhesive film and are arranged in a first direction. The first and second driving pads overlap with the first and second signal pads, respectively. The display device may be configured to satisfy the inequality:T≥G+B×SW+S.