Circuit Board Adhesive Overflow Detection via Metal Layer Hollows
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Solution Overview
Problem
Current display technologies face challenges in detecting adhesive overflow on flexible printed circuit boards (FPCs) efficiently, which affects the compactness and functionality of display modules, particularly in full-screen, long battery life, and 5G communication applications.
Innovation Solution
A circuit board design incorporating a substrate, metal layer, insulating layer, adhesive layer, and an adhesive overflow detection line, where the metal layer and insulating layer are used to visually detect adhesive overflow through hollow parts or color differences, preventing adhesive from spreading to peripheral areas and ensuring accurate detection without physical structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive layer is applied to cover the circuit board, then bonding strength is improved, but adhesive may overflow to golden finger area causing functional failure
Solution Approach 1:
The circuit board is divided into a device area and a peripheral area, with the adhesive layer selectively applied only to the device area. This segmentation prevents adhesive overflow into the peripheral area containing golden fingers, maintaining functionality while ensuring bonding strength where needed.
Solution Approach 2:
The adhesive layer is applied with different coverage characteristics in different areas: fully covering the device area for bonding, and completely avoiding the peripheral area to prevent overflow. This local quality differentiation resolves the contradiction between achieving sufficient bonding and preventing harmful overflow.
2Area of stationary object
If FPC size is reduced to improve compactness, then display module size is reduced, but detection of adhesive overflow becomes more difficult
Solution Approach 1:
The detection method transitions from spatial measurement to optical detection by introducing a detection line with different refractive index. This allows overflow detection without increasing physical dimensions, maintaining compactness while enabling reliable detection through optical property differences.
Solution Approach 2:
The detection line utilizes refractive index differences to create visible optical contrast when adhesive overflows. This optical property change enables easy visual or automated detection of overflow conditions without requiring additional space or complex measurement systems.
3Measurement precision
If detection method uses physical structures, then detection accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
Instead of using complex physical detection structures, the patent uses a simplified detection line pattern that replicates the boundary between device and peripheral areas. This optical copy approach achieves accurate detection without the complexity of mechanical or electronic sensing systems.
Solution Approach 2:
The detection mechanism replaces potential mechanical or electronic sensing systems with an optical-based method using refractive index differences. This substitution simplifies the detection system while maintaining or improving accuracy, reducing device complexity and manufacturing cost.
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 enhances detection accuracy and efficiency, saving costs while improving the quality and production yield of display devices by preventing adhesive overflow and maintaining the compactness required for modern display module designs.
Implementation Method 1
a detection line which is used for detecting whether an adhesive layer overflows; the detection line is formed in a peripheral area of the circuit board... a portion of the first insulating layer in the peripheral area has a color different from other portions of the first insulating layer
Data Source
AI summary
A circuit board and a display device are provided. The circuit board has a device area and a peripheral area surrounding the device area. The circuit board includes a substrate, a metal layer, a first insulating layer, an adhesive layer, and an adhesive overflow detection line. The metal layer, the first insulating layer, and the adhesive layer are disposed at a same side of the substrate. The metal layer and the first insulating layer cover at least a part of the peripheral area. The metal layer is disposed between the first insulating layer and the substrate. The adhesive layer is disposed at a side of the first insulating layer away from the substrate and in the peripheral area. The adhesive overflow detection line is located in the metal layer and the metal layer in the peripheral area is provided with hollow parts; and/or the adhesive overflow detection line is located in the first insulating layer and a portion of the first insulating layer in the peripheral area has a color different from other potions.