Display PCB Cut-Line Structure for Easier Rework Removal
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Solution Overview
Problem
Existing display devices face challenges during rework processes due to the difficulty in separating the PCB from the cover panel without damaging the panel, leading to impaired workability, prolonged process time, and increased risk of operator injury.
Innovation Solution
A display device structure featuring a cut line region around the PCB attachment area on the cover panel, with an enlarged size and a partially cut dotted boundary, and an adhesive layer with reduced adhesiveness or openings in the cut line region, allowing easy detachment of the PCB without damaging the cover panel, and optionally incorporating rework handles for enhanced ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the PCB is firmly attached to the cover panel using adhesive, then the attachment strength is improved, but the ease of separation during rework deteriorates
Solution Approach 1:
The adhesive layer is segmented into different regions: a first adhesive region with strong adhesiveness for securing the PCB, and a second adhesive region with weak or no adhesiveness for enabling easy separation during rework. This segmentation allows the same adhesive layer to provide both strong attachment and easy detachment properties in different areas.
Solution Approach 2:
Different adhesive properties are applied to different locations of the adhesive layer. The first adhesive region (where the PCB is attached) has strong bonding characteristics, while the second adhesive region (around the cut line) has weak or eliminated adhesiveness. This local differentiation resolves the contradiction by providing strong attachment where needed and easy separation where required for rework.
2Reliability
If the PCB is firmly attached to the cover panel, then the reliability of connection is improved, but the risk of panel damage during removal increases
Solution Approach 1:
The adhesive layer is divided into a first adhesive region providing strong bonding for reliable connection and a second adhesive region with weak adhesiveness that allows clean separation during removal. This prevents damage to the cover panel while maintaining reliable PCB attachment during normal operation.
Solution Approach 2:
The adhesive layer is pre-configured with a weak adhesiveness region before the PCB is attached. This preliminary design ensures that during rework, the PCB can be removed without damaging the cover panel, as the weak adhesiveness region is already prepared to facilitate clean separation.
3Strength
If a large adhesive area is used to secure the PCB, then the attachment strength is improved, but the process time for removal increases
Solution Approach 1:
The adhesive layer is segmented into a first adhesive region with strong bonding for secure attachment and a second adhesive region with weak adhesiveness for rapid separation. This allows the PCB to be firmly attached during operation while enabling quick removal during rework without requiring extensive adhesive removal time.
4Reliability
If the adhesive layer is made uniformly strong, then the attachment reliability is improved, but the ease of manufacture for rework purposes deteriorates
Solution Approach 1:
The adhesive layer exhibits local quality differentiation: the first adhesive region has strong bonding properties for reliable PCB attachment, while the second adhesive region has weak or no adhesiveness to facilitate easy rework. This local quality variation is designed into the adhesive layer structure to simultaneously achieve reliable attachment and ease of rework manufacturing.
Data Source
AI summary
A display device includes a display panel, a base film, which is attached to the display panel and protects the display panel, a cover panel attached to the base film by an adhesive layer on a side of the base film opposite to a side of the base film to which the display panel is attached, and a printed circuit board (PCB) attached to the cover panel by PCB adhesive therebetween and electrically connected to the display panel via a flexible printed circuit board (FPCB), where a cut line region is formed around an area where the PCB is attached on the cover panel to have an area larger than the area of the PCB in a plan view.